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MG MGB GT V8 Factory Originals Technical - Grand Nat'l Turbo V6?
|I have no idea if it would fit, or if the heat would just pose an insoluble problem in a B's tight engine bay: but has anyone ever tried a 3.8 Turbo V6 from a Buick Grand National (I was gonna say ~1991 or something like that)? This is apparently a 60-degree motor and is supposed to simply tear up the road (though I understand having the turbos suddenly spool up in the middle of a turn can prove interesting!). Most of the naturally aspirated V6s I'm familiar with just don't provide the torque I would think would be the most fun, but this turbo setup is apparently all that and a bag of chips ... love to hear your comments.|
I can't comment on the drivability or performance of the Buick V6, but I can comment on it's size and configuration.
It is a 90 degree V6, and has the same dimensions as the BOP/Rover V8, minus 1 cylinder. This V6 was derived from the aluminum V8 to be made using much of the same tooling as the V8.
The Buick V6 IS A 90 DEGREE BLOCK. 'Means if you look at the angle between the banks of pistons you will find that they are 90 degrees. Stop dreaming and start reading. Just because it is a v6 does not mean it is a 60 degree block. Plenty of rough running 90 degree v6's out there. I have one in my van... 4.3 FI v6. You can use a 90 degree v6 if you want to do the surgery on the engine compartment. You can fit a Cummings Deisel or a Dodge Viper v10 if you really want to.... I would tend to think most people who are thinking about swapping in a more powerful engine into their "B" are also keeping in mind that they want to keep most of the handling qualities of their car. Reminds me of a fellow who I knew years ago, decided he would inprove his MKI frog eye Sprite and installed a 283 V8 into it. Sort of ended up as a v8 shopping cart. What's the point? Power for the sake of power? Short man syndrome? Give me some of that stuff you are smoking... Alan
|Hey Alan, chill, boss. Just a thought! I'm plenty tall, thanks (too tall for a B really) ... really just kicking some ideas around ... that's what this BBS is about, no? I realize it's early there in Seattle and you may not have had your coffee yet! Would indeed like to keep handling qualities - my initial reckoning was that the weight would not be far off. Sounds like a non-starter though. A Rover is probably a much better answer.|
"You can use a 90 degree v6 if you want to do the surgery on the engine compartment."
What surgery? The Buick V6 is just a short BOP/Rover, so less surgery is required to stuff it in than the V8. The Turbo may require more work, but not the V6 alone.
Looks like you could stand to do a bit more reading yourself.
Alan also wrote:
" I would tend to think most people who are thinking about swapping in a more powerful engine into their "B" are also keeping in mind that they want to keep most of the handling qualities of their car."
Probably, but neither you, Barry, nor myself are "most people." We are all individuals, with individual tastes. Some of us want a road car, some of us want a show car, and some of us want a drag racer. Some of us just want a novelty. Some of us really want a challenge, while some of us want to go with the tried and true. Some of us want it all.
Just as an example of the odd things that some of us want, how about a Bugeye sprite with a 478 Chrysler Hemi?
Not my cup of tea, but damned if I don't admire the man and his car.
I still say go with a Ford 302! The Buick 3.8 V6 weighs just a bit less than a Ford 302, and about the same as the B engine. If you can find aluminum heads for it, you could reduce the weight by about 35 - 40 pounds. In the past, aluminum heads were available, but I haven't seen them advertised lately. At one time, that engine was the hot ticket; they were even ran in the Indy 500 with great success. At that time, there was a large selection of go-fast parts for it, and they should still be around at various swap meets.
Had my coffee feeeling great now... As I said, if you decide to use a 3.8 90 DEGREE v6, you still have to do the surgery if you want the gearshift to be at the same place as say a Rover 3.5 Aluminum. You could place the engine forward and not have surgery, but then the gear shift would be forward in the car the same amount Yeah,aluminum heads are still available and they fit on the 4.1 v6 as well, a larger displacement of the 3.8 engine found in the Buick and some Cadillac models. Been doing some reading..... Alan
|That Sprite is simply amazing! I wonder where one's feet go, though?????!? Still, it looks like he's left the seats in the stock locations. Anyone seen it in person? What an incredible little car! I wish he had a snap of the footwells.|
What interferes with the body on the V6 Buick that doesn't interfere on its sister V8 when they are placed equally far back?
Most of the naturally aspirated V6s I'm familiar with just don't provide the torque I would think would be the most fun, but this turbo setup is apparently all that and a bag of chips ... love to hear your comments.
A crate motor 3.4L 60 degree V6 provides 200 foot pounds of torque with all emmissions items attched and a two barrel carburettor running the system. If you start modifying these from there, as with any motor, you will get more. The 215 BOP/R is putting out that much torque as well. In a light car such as an MG B that weighs in at 2000 to 2500 Lbs, depending on what the car has installed in it for driveline, interior and body kits, vs cars such as the V6 Camaro that weigh in at 3200 Lbs on the light side- The BOP/R, a 60 degree motor or a modified 302 can feel like a modified BBC 454 CI V8 in an old muscle car.
Keep in mind that the average MG B conversion (Please correct me if I am wrong) weighs in at around 2300 Lbs. The light production Camaros 1980-present come in at 3200 to 3600 Lbs. The Lightest Camaro Vs the average MG B has a 900 Lbs difference!
Whats that equation? For every 10 Lbs you remove from a car its like gaining 1 BHP for the quarter mile times...?
10/900= 90 BHP
So to remove 900 Lbs from a Camaro (or any other car) would be the same as adding 90 BHP to that car. I have -not- done the math on this, but what would that do for 0-60 times and qurter mile times, not to mention slolom times and G force?
Barry, how much power and torque do you think is enough for your particular application?
|BMC Brian McCullough|
|I definitely recall seeing a MGB with a grand national engine/turbo in one of the hot rod magizines. Most likely Car Craft or Hot Rod. It was a full feature article of 2 or 3 pages. No idea how to research which mag and which issue.|
My point was: no matter which engine you use - the v6 or the v8 (both 90 degrees) you will still have to cut the firewall for clearance and "relieve" the tunnel for the trans. If both engines are the same width and the trans is in the same place, then you will still have to cut the firewall unless you have a rubber bumper car. Admittedly, the v6 will be shorter by one cylinder on each side but the bellhousing to block junction will be in the same place (just in front of the heater) if the trans is in the same location in either situation. Just because the v6 is shorter does not mean it will fit hassle free. It is still the same width and cylinders 3&6 will interfere with the firewall unless "surgery" is done. However it does bring up a good question that is; will a set of modified Buick v8 headers fit and not have to be routed through the fenderwells but follow the same path as the Rover v8 headers? If so, a 4.1 with aluminum heads and FI could be a runner. Smokey Yunnick has some good Buick v6 stuff that was developed for Nascar racing. Alan
|Many people won't use the 4.1 because of the siamesed cylinders and overheating issues when they are built up, but the siamesed SBC's seen to be acceptable, not sure why.|
|Brian, very good analysis. Every once in a while you hear some talk about torque in these pages. This may be because they haven't experienced any thing else in an MGB. I know and you know that you can throw big torque out the window and still get better performance out of a stock 3.4 V6 than you can a stock 215 Buick. As you know the Buick has nearly the same torque and a 8 more inches plus 2 more cylinders. The weight difference of the Buick over the 3.4 engine alone robs away performance and on bigger, heavier engines makes handling a nightmare if you don't go the expense of engineering the chassis. Some guys prefer to live on the edge like the Bugeye mentioned above. That's a straight line go cart for sure but it's cool.I wasn't aware that so much cutting,welding, BFH engineering was involved to get a Buick/Rover/90°V6 in the MGB.I have been reading the archives and recent material on the subject. It gives me the chills, what a nightmare.|
For the life of me I can't understand why anyone(not you) has to lean on the word torque when making reference to HP and/or performance.I can put it in perspective this way:
Sure, a person can get an elephant to pull a dog sled(torque)and reach his destination but if you put a sled dog pulling a dog sled you'll get the sled there a ellava lot faster. Adios
|"Whats that equation? For every 10 Lbs you remove from a car its like gaining 1 BHP for the quarter mile times...?"|
That's a pretty good rule of thumb, but it's only a rule of thumb, and it is applicable in only a narrow range of applications. Consider the following examples: A 1000 pound forklift with a 10HP motor, a 2500 pound MGB with a 250HP motor, and a 2500 pound dragster with a 2500HP motor. The power to weight ratios (pounds per horsepower)are, respectively, 100:1, 10:1, and 1:1. For the forklift, you would have to remove 100 pounds to get the equivalent of 1 extra HP, 10 for the MGB, but only 1 for the dragster.
There is no such thing as "horsepower." Horsepower is a bogus term invented a couple of centuries ago to impress the common man with the awesome power of the newfangled steam engine. Horsepower cannot be measured. It is CALCULATED from the measured torque. The ONLY thing an engine produces, besides smoke, heat, and noise, is torque. The only difference between one engine and another is how much torque and at what rpm. Screw horsepower - torque is what we live for.
|I have reading this listing with great interest! I have to admit to being a layman when it comes to these terms, but I have learned quit a bit from these kind of BBS's and there seems to be a few things that stick out to me.|
1.I have looked at the graphs and it appears that torque is the factor that will be most felt when driving either hard or normal.
2. Unless you operate your vehicle at its very limits then you will not seee thos last 20 or so HP values. so a person like me (not a racer, but an occasional stop light bandit) will operate in max torque areas not max HP.
Someone once wrote here that "HP is for magazines and Torque is what makes cars go." the more I read the more that statement seems to hold true.
just my 2 cents
"Sure, a person can get an elephant to pull a dog sled(torque)and reach his destination but if you put a sled dog pulling a dog sled you'll get the sled there a ellava lot faster."
Your elephant/sled dog analogy is interesting, let's take it a bit further. The elephant in your example is running at about one rpm, geared one-to-one to the sled; the sled dog is running about 100 rpm, also geared one-to-one to the sled. Let's slap a 1000 pound payload on that sled and see what happens. The poor little doggy won't have enough torque to operate at 100 rpm and pull the sled. He'll stall out at zero rpm. He'll have to be geared down to pull the sled at one rpm while he runs at 100, if he even has enough torque to do it. Gear the elephant up to where his one rpm equates to 100 rpm at the sled, and he'll fling that sled over the ice very nicely. Torque is King, long live torque!
|Dann, that's just plain nonsensical. I don't understand at all your remark|
> Every once in a while you hear some talk about
> torque in these pages. This may be because they
> haven't experienced any thing else in an MGB.
What???? An MGB 4-banger has about 60 ft-lbs of torque. That's absolutely miniscule.
> I know and you know that you can throw big torque
> out the window and still get better performance out > of a stock 3.4 V6 than you can a stock 215 Buick.
That'd be news to many. Maybe you're talking about a DOHC motor that can be run at zillions of rpms, and get performance that way. But if you're talkin' pushrods, hoss, I just can't see it in 10^6 years! Wow. Come back to our planet.
|dan,,, i was checking the figures, is that a male or female elephant?, siberian husky or malamute?, safety faster ( torquier ) jim|
|A 70s issue of Hot Rod had a twin turbo 90 degree Buick in a MGB. I remember it being called Bock's Beauty or something like that. It was very highly modified. As with most magazine cars it was very professonally done $$$$.|
|Dann W. and Dan M.,|
You both bring up very interesting and good points.
There is a 3.4L SFI motor in an MG B and we know it has over 200 BHP and 200 Lbs torque. It propells itself very well down the road. That car is a very heavy MG as it has many extras on it. My 1982 S10 with the SAME motor but fewer aftermarket goodies produces an estimated 170 BHP and 200 Lbs torque. The S10 with me in the seat, a passenger, a full tank of gas, my tandem axle car trailer and a 3000 pound vehicle on that trailer (all weighing in at 7200 Lbs) goes down the freeway just fine at 80 MPH with pedal left to spare.
That MGB that I was discribing has the Exact same gearbox and rear end ratios as my custom S10 and weighs aproximately 400 Lbs less.... I would Bet that the MG will out run me every time just on the weight issue.
Bhp has a bit to do with how much the motor developes at higher revolution speeds, but is not as acurate as just reading a torque curve chart. One issue to consider is where the motor of choice developes power.. I personally never want a motor that has its torque peek at 1500 RPM unless its a diesel in a large rig.. That early torque -usually- signifies no RPM range (or limited range) and is not good for sport in an MG B.
I believe Dann is correct...
But as you probably have figured out by now, I am bias as most people here are to thier own designs. :-)
A 3.4L V6 is 204 CI
A 3.5L V8 is 215 CI
11Cubic inch difference by old school measurements.
Again, a totally stock 3.4L crate motor that is built by GM for use with a catalitic converter, a 2 BBL carb, all emmissions equipment installed and passes the emmissions test is rated at 160 BHP and 200 Lbs torque. Manifolds, not headers and so on...... Now go to a 2bbl equipped motor from the 215 buick and tell me those figures, keeping in mind that emmissions standards were not around at that time. The V6 provides a higher revving limit (more power up top) and therefore allows better use of a lower (higher numerical) rear end.
When we start talking about building these motors and adding 4bbl, bigger cams, FI, or any thing else, we must also compare apples to apples. Thats all I am attempting to do here.
The 302? Well, they have both motors beat in Torque period. However, it looks like those of you who are building the 302 V8 really have to invest a substantial amount onto your B to get the weight down and time rebuilding the inner sheet metal, non the less they msut be fast when done.
Fun discussion, but I am WAY off the subject now! :-)
|BMC Brian McCullough|
|I agree with Dan M., torque is what rules. Horsepower is only based off of torque. I remember several years ago Hot Rod wrote an article about the relationship between torque and horsepower. I did a quick search and found this site and thought that it might be useful to some:|
(on another note horsepower and torque must always be equal at 5252 rpm)
|If you install a Buick V6 so the bell housing end of the motor is in the same place as a 215 Buick V8 then all the work at the back would be the same and the work at the front would be easier by the distance of the front pair of cylinders. Thats been stated, but heres something to think about The center point of the carburetor (if so equipped) will be back farther where there is more room than on the V8. That may be a half an inch, but that could allow a better air filter.|
|Jim, Due to the seriousness of the experiment, I think they were both neutered so there wouldn't be an attraction:-) |
Brian hang in there buddy we know we got the right stuff:-)
Dan M wrote "Gear the elephant up to where his one rpm equates to 100 rpm at the sled, and he'll fling that sled over the ice very nicely."
A very interesting and very humorous thread. That is exactly my point, how much payload are we talking about. How much torque do you need from an engine to propel a MGB in what we would consider a performance category. I'm talking about mid 14's on a tight budget.
An engine producing 400 ft. lbs.of torque @ 2500 rpm with a synthetic 400 HP certainly would not be a desirable engine to use in a swap. Typically this would be a diesel engine. Bigger torque always means bigger, heavier engines as a rule. An engine producing these figures would probably weigh 500 lbs. No amount of gearing could help the performance situation because you would run out of RPM in a hurry. The sled dog will long gone.
The horsepower to weight formula is always the deciding factor in any contest that I have ever witnessed. I have never seen any one advertise products by mere torque values. How do you explain the rice rockets performance? They have low torque figures, but they also have very high RPM and horsepower. You need some torque to get the vehicle moving from a stationary position after that kinetic energy is a factor and friction losses will overcome torque and HP on the upper end. After most of the horsepower and torque is all used up in a vehicle as it approaches top end the engine will only needto produce a few HP to hold a vehicle at near top speed anyway.
Torque to be simply understood is a name given to the science of rating the power output of an engine or electric motor and wasn't recognized as much until the advent of the steam engine as Dan mentioned. The steam engine locomotive was very powerful indeed and it carried goods and passengers all over this nation but the very light Stanley Steamer automobile could achieve over a 100 mph over a very long stretch of road and took a long time. It had lots of torque but wasn't no screamer off the line.
When I am talking performance I want to talk about a very light engine with high HP and installed in a very light car to make it go and handle well at a price that won't cause the need for a second mortgage on your house. Thanks, Dann
|Bill Withum. It's been proven over and over that the stock push rod 3.4 MGB that I am referring to will absolutely blow the doors of a stock 215 Buick MGB any way, any time.All this is happening at 7200 RPM also. While I'm on this planet, I'll take any bet and double the money if I lose a sanctified drag race. These are modern engines friend, not dinosaurs. I'm sorry you can't accept that but you offered a challenge when you made your statement |
Bill Withum, Charlotte, NC USA "That'd be news to many. Maybe you're talking about a DOHC motor that can be run at zillions of rpms, and get performance that way. But if you're talkin' pushrods, hoss, I just can't see it in 10^6 years! Wow. Come back to our planet.
Remember money talks............etc. Thanks, Dann
|I didn't know that priests blessed drag races. Maybe sanctioned would be a better word?;)|
|The rice rockets certainly do spit in the face of the "there's no replacement for displacement" school of thought. Honda S2000's barely have enough torque to pull the car when you put a set of golf clubs in the *cough* trunk. The S2000 is rated at 240 hp @ 8300 rpm's, with peak torque of 153 ft lbs @ 7500 rpm. Interestingly enough, redline is 9,000 rpm's -- All of this out of a 1997 cc engine. New conversion motor? Anyone? ;) |
Is someone willing to explain to me how a 1.9L 4 cylinder with a relatively small amount of torque does 14.3 second quarter miles at 100 mph -- the same essential goal as Dann Wade was searching for with the 3.4L V6? I'm not trying to sound stupid here, but it seems to be two very different methods of skinning the same cat, both with good results...
|Dann, you wouldn't wanna make that little wager with a low buck MG with a hairdried, fuel injected pinto 4 in it, would you? There are a few dinosaurs that have a little bite to them, and I need motivation to hurry up and finish this thing off. ;-)|
|Back to the topic, 3500 lb. GN's do the quarter in the tens, so I suspect that a similarly powered B wouldn't do much worse, but you would be building a car strictly for the strip if you were to expect the same results. Getting rid of the heat in everyday traffic would be a major problem.|
|George B. Very good. I stand corrected. I use a Dragon Point and Speak A.I. program to type with. That one got by me. Sanctioned is correct. I also noticed if I say Jesus Christ the program spits out thesis crisis. I'll pay closer attention. I also taught the program to swear in case I needed to describe a problem with an MGB :-)|
G.P. Copes: You are comparing apples to oranges Mr. Copes. I was speaking of STOCK. Of course anyone knows a stock Pinto engine couldn't possibly be compared. If you will allow me the same mods I will triple the stakes. What are your 1/4 mile times? I would suspect they would be in the middle 14's. If you are talking about the overhead cam later model Pinto I can see it running in the 13's. A custom turbo shop just opened down the street.........hmmmmmmmm,very tempting!
It sounds like a very sweet set up. Lotsa fun there too. Enjoy!
Justin, I would be foolish to diagree with you and the Honda certainly does change the rules.
|Well, we have strayed a long way from the original topic, but I don't think we've exhausted the interest in the subject as it now stands, that is, Dann and Brian's V6 vs BOP/Rover/ vs Ford 302 vs ???, and torque vs horsepower.|
OK, let me say this about that:
Torque vs horsepower:
First of all, I stand by my statement that there is no such thing as horsepower. Horsepower is a bogus term that has meaning only because if you understand what it is, you can extrapolate torque from it, as horsepower is nothing more than torque times rpm divided by a constant. When you feel a push in your backside from mashing the go-fast pedal, what you are feeling is torque, pure and simple. What distinguishes one engine from another is the amount of torque, and the rpm band where that torque is produced.
For some applications, an engine that produces gobs of torque at a low rpm is better than one that produces gobs of torque at a high rpm. For other applications, the inverse is true. For most of us, for most of our driving, we need/want an engine that produces a fairly flat torque curve in the 1500 - 6000 rpm band, more-or-less. Luckily, most engines that we might want to use produces torque in that rpm band. For street use, most of us would be happier with an engine that produced 200lbft of torque from 2000 - 5000 rpm, with a sharp drop-off over 5500, than we would with an engine that produced 300lbft of torque from 6000 to 10,000, but didn't produce over 100lbft below 5500 rpm. If you do the math to calculate the mythical horsepower for these engines, and listed the peak HP figures, the latter engine would give a MUCH higher number than the former. Nonetheless, I don't really believe any of us would really want to drive the higher HP version on the street. On the track, absolutely, but not on the street. The Ford GT40 engine for example, delivers over 300lbft of torque from 2000 to 6000 rpm, and very few of us have any need to exceed 6000 rpm on the street. Not with 300lbft below that range, and then only if we are in an actual race situation.
Our hypothetical little doggy might be able to handle an empty sled, but in a real world situation, with a passenger and a couple of weeks worth of supplies on board, he would just sit there on the ice and look silly. He’ll be waiting for his buddies to show up to help out – that why dog sleds are pulled by large teams of dogs – one dog just doesn’t have the torque needed to pull the sled.
Dann wrote: "Torque to be simply understood is a name given to the science of rating the power output of an engine or electric motor and wasn't recognized as much until the advent of the steam engine as Dan mentioned."
Dann, I don’t believe you really meant to say that; I think you meant to say “horsepower” instead of torque. Torque is a fundamental property of physics, and has been known and understood since ancient times. The output of an engine IS torque – it’s the only parameter of engine performance that can be measured directly. Horsepower is the term devised to help relate the performance of the early steam engines to something the average person could understand. Way back when, when steam engine were basically doing the same jobs that were being doing by horses, ie, pulling carts, this made sense. A 10 HP steam engine could pull the same weight wagon as 10 horses, (at a walking pace as well – speed came later) so there was a 1 to 1 correlation. This is no longer true. The work done by 250 horses has no relevance whatever to the work done by a 250 HP engine. Unfortunately, we are now stuck with that outmoded rating term. Personally, I’d like to see the term “horsepower” eliminated from usage.
V6 vs V8:
I don't believe anybody is trying to say that the 3.4L V6 is not an excellent choice for an MGB, (as a matter of fact, I’m very seriously considering giving you V6 guys a call about a V6 for my TR6 – the stock one that needs a new engine, and the one I’ll be selling when it’s done, not the 302 Ford conversion) but I do believe its benefits are being exaggerated. Perhaps a point-by-point comparison of the three most popular options might be worthwhile.
1. Weight (complete engines/transmissions, ready to run): Bop/Rover: 440, Ford 302: 520, MGB: 495, 3.4L V6:???? Lighter is better, of course, but within practical limits, none of these engines presents an overwhelming weight advantage/disadvantage. The Ford only adds 25 pounds, the BOP/Rover drops 55 pounds. From a straight line performance standpoint, the Ford produces enough power to way more than offset the added weight. From a handling standpoint, the handling will not be noticeably hurt by 25 pounds in any but the most competitive events. Reducing the weight by 100 pounds or so should make a noticeable improvement.
2. Power: It’s hard to compare power, because the power ratings of each engine line varies greatly, but here are some typical numbers. Ford 302 GT40 crate engine: 375 HP, Over 300lbft torque from just off idle to redline, peak at 360lbft. Stock Mustang 302: 200 – 250 HP, torque figures not available to me at this time. Original 215 V8 as installed in the MGBV8: 137HP, 193lbft torque. 3.4L V6: (numbers supplied by Dann and Brian) 200HP, 200lbft. 3.5L BOP/Rover V8 as used in the new Morgans: 188HP, torque figures not listed. The 4.5L version, as used in new Land Rovers: 217HP, 300lbft.
Using a stock 215 from an early BOP provides the least power, but even then, the torque figures come very close to the 3.4L V6. Later aluminum block V8s, ranging in displacement from 3.5 all the way to 5L in as used in Land Rovers, TVRs, etc, provide a dramatic improvement in power, but the Ford is way in front in this department.
3. Ease of installation: By far, the easiest is the BOP/R V8 into a late model MGB, a simple drop-in installation. The 3.4V6 should go in without any surgery required, but there is still work to be done to mount the engine and to modify the transmission crossmember. Other minor changes will need to be made as well, but overall, not a difficult swap, I believe.
The BOP/R swap into an earlier MGB requires some sheet metal surgery, but it isn’t all that difficult to do. The modifications have been made so many times, and so much information is available on how to do it, that it really should be considered minor. Welding and repainting under the hood will be required. Motor mounts, steering mods, and transmission crossmember mods will also be required.
The Ford 302 will require the same modifications as the BOP/R, but the motor mounts will be a bit more difficult, as they will have to be made up on the job. Mounts for the BOP/R can be purchased. Additionally, the front crossmember will have to be notched for oil pan clearance. Notching the crossmember is a simple task, and can be done in an easy afternoon’s work by anyone with a cutting torch and a welder. Hiring the work done, if you don’t have these tools, will not be very expensive, certainly less than $100.
4. Cost: Cost is like a room full of hot air – hot air will expand or contract to fill the room, no matter what the size of the room; cost will expand or contract to consume your entire budget, whatever your budget may be.
Ford 302: A brand new GT40 crate engine can be bought at full retail for $3200, less if you shop around. Add another $800 or so to that for the accessories, and you have about $4000 in a ready to run engine, with 360 lbft torque! A good used, low mileage engine can be bought “retail” from a junkyard for around $1200. If you’re clever, you can get them for a lot less. That’s a complete engine, ready to run. You’ll probably want to get a bigger radiator, so add another $200 - $300 for that. The other parts/pieces you’ll need will pretty much be the same for any engine you choose.
BOP/Rover: Used engines can be had for anywhere from $350 up to $2000, or more, depending on year and condition. That’s for a complete ready to run engine, but you will probably want to change a few things if you are using an early engine, so a few hundred more may be needed before you’re through. A rebuilt engine will cost you somewhere in the neighborhood of $4000 - $6000, as far as I know.
Gen II FWD 3.4L V6: Killer BV6 will sell you a used engine for $1000. I have no idea what you might get one for from a junkyard yourself, but presumably less if you know the right people. A conversion kit to convert to RWD is $350 from Killer BV6, a water pump adapter plate, to convert to a remote electric water pump, is $150, and the electric pump is another $225, so we’re looking at a total of $1750. I have taken these numbers from the KillerBV6 website, and it’s possible that I have mis-interpreted them, so check with Dann before accepting these figures as fact. A motor mount kit is available for $295. I have no idea what this kit consists of, and how much of it could be made at home by the average back yard builder, so I don’t know how this factors into the cost comparisons. Other than that, the remaining items should be comparable for this engine to the others.
All in all, it should be no trouble to convert to either of the three engines for under $5000 if you do the work yourself. If you hire it out, the costs will vary greatly depending on who you get to do the work, but you should be able to get it done for under $10,000 total, regardless of which engine you choose. I doubt that a professional installer would charge much less for the V6 than for a V8, at least not until they become as familiar with it as they are with the others. On a cost basis, then, the three engines are too close to call.
5. Intangibles: When all is said and done, it will probably be the intangibles that make the difference. Some of us are inclined towards originality, and will choose the BOP/Rover to mimic early factory efforts. Some of us lean towards maximum power, which will lead to the Ford. Other are more concerned about the amount of work involved, and will choose the BOP/Rover for late models, or the V6 for early models. Some may be excited by technology, and may go with the V6 and computer controlled fuel injection. Some may be a bit old fashioned, and want to stick to carburetors. For me, it has to be a V8 – regardless of make. No valid reason for that, it’s just my unyielding, uncompromising, choice – no other options even considered. If I’m going to have a V8, it may as well be a powerful V8, so that leads me to the Ford. Others will take a different path.
The best thing about this whole discussion is that no matter what approach you take, it will be the right one – there is no wrong approach. As long as you’re happy with it, that is.
Whew! A lot more than I meant to say - my apologies for being so long-winded
You didn't mention the 3.8 V6 as per the original query. As used in the GN's, it developes far more power than any size Rover engine, also more than 302 stang engines.
The aluminum SBC should be factored in as well. Nobody seems to mention that no crossmember mods would have to be made with this engine and it should be compatible in price to the higher powered Ford engines.
|Whew, I think I'll let this one rest. The point I was trying to make is now so far out I can't even determine it myself.|
Dan M. Your article is certainly worth reading.
George B. As for a comment for the original thread I can add something to that. At some point there has to be a compromise in every engine swap. The installation of an Allison airplane engine rated @ 1000 HP engine in a light weight car might sound radical to some but others would do it because of their need for it. This was done years ago when the cheap way to get HP into a car was to keep adding a lot of cylinders. I don't remember the purpose of doing the swap. It seems like some get hooked on extreme machines. From what I read here most would settle for about 250 HP or less which is reasonable but others a lot more which may be a fantasy turned into reality and not the norm but then again what is normal? The Hemi Bugeye is a good example of over kill in my way of thinking but must be applauded because it is so awesome. I tend to stick with all around usability, not because I don't like spine smashing power but usually it is less expensive.
Now as far as putting a Grand National engine in an MGB. Is it practical? No. Is it feasible? Maybe. Would it be fun to drive? Yes, way beyond comprehension. The engine was 90 degree configuration and was not produced after 1987 because they dropped the GN/GNX after that year. After Pontiac redeveloped the heads they used it in a Turbo version T/A. I own a 1989 Pontiac Trans Am Turbo 20th Anniversary. It had more rated HP then the GNX as it came from the factory. Nobody paid much attention to the car as there was only 1400 some produced. It was rated at 250 HP which wasn't correct. Mine registered 331 HP with more than 400 ft. lbs. of torque on the Dyno. When driving the car the power started coming on at 1600 rpm and the power comes up real fast. When it reached around 2500 the tires were trying to break loose and the power was phenomenal up to 6500 rpm.
This car weighs over 3400 lbs and turned a 13.6 1/4 mile time. Not so fast these days but the absolute King over all popular Detroit iron production cars at the time.
My Point? Putting this kind of power system in an MGB might be dangerous because of the surge of power incurred shortly after the turbo winds up. It would probably make the car skitter easily. Yes, these problems could be corrected but then you would end up with more of a dragster then a sports car. There would be great compromises when try to find a place for the intercooler. Anyway I addressed the original query about the swap. It's cold as heck here in Dayton so I think I'll run and have a hot tea with a shot of rum. Thanks for listening, Dann
|All this talk of power, torque, car wieght, HP. NO one of these is the most important, nor least important. They ALL work together to make the car perform or not.|
Our cars are LIGHT, but I see heavier cars with the same power outrun me in thr 1/4. Why?? Well set-up is one thing, but it comes down to wight on the tires to hold them from spinning!
Torque - moves mass, is most important in 1st and 2nd gearing coming off the line.
Also exiting coerners, but you can downshift into corner and spin a motor up to get into HP range to offset that.
HP - Down track and end of straight away acceleration, this pushes the car after the torque gets the vehicle up and running.
Gearing - Is KET to getting off the line and then keeping speed increasing before redline. to low, she will pull off line but fall on her face down the straight. To high and she iwll not get rolling well.
TRACTION - probably THE limiting factor in a MGB. the lightwieght is actually a hinderance for drag racing, they simply don't have the mass to make the tices hold the road. Even with wide tires there is a limit between weight on the tires and contact patch etc..
Suspension - There is only so much that has been done and can be done with a MGB suspension. Roadracing and Rallying are the cars stronger points. They corner decently and handle rough roads well with in proper tune. Drag racing is much harder fo them due to extreeme forces on a old design and limited options for counteracting it all.
It is ALL a balancing act folks. for a fun daily driver type that would see LOTS of commuting miles I would probably do a V6 with auto tranny out of a camaro or Firechicken (YES I said Auto, We have the worst traffic in country, I sit in freeway parking lots allot) Better mileage than a V8 but still plenty quick and lots of performance parts.. For a really fun car to drive aorund whenever, I would stay with my 302/T5 combo.
I have to disagree with you on the weight issue. Funny cars of a few years back were certainly no heavier the an MGB and were almost as fast as the gasoline powered dragsters. Good, sticky tires, adequate power and a suspension that allows weight transfer should be the key to quick runs. If more weight made cars faster everybody would be building their cars as heavy as possible rather than trying weight saving measures.
|But George, how are you going to modify the MGB to act like a funny car that was built from the ground up to run drags? Just not practical. Adding ballast though seems to be something that has been used successfully at times, so maybe Larry's point is valid. A little lead in the rear bumper just might make it quicker in the 1/4, depending on the car, and maybe without hurting it too much otherwise. My opinion though, is if you wanted a drag racer wouldn't a Chevelle or something like that make a better starting point?|
I guess I did need to clarrify that. it is WHERE the weight is that is also a key and that comes back to the design and suspension set-up. Engines are mid-rear mounted. Driver is sitting almost between the rear wheels. Funnycars are built so that 80%+ of their weight rotates to the back tires upon launch, hence the need for stout wheel bars with steel roller wheels. Not ot mention the tires they use are so wide you would be very lucky to get them under a MGB without having then almost touching on the inside.
There is a wieght issue a featherlight car will not hook that well unless every once of that weight somehow ends up on the rear wheels. That is one reason the rail top fuel guys are SOOO long now. and the chassis actually flex quite a bit.. then the nos tries to rotatup on on one of them all the chassis wieght is loaded ontp the rear wheels, and jjust enough remains on the fronts to maintain a semblance of control. Whatch one run you will see the chassis take a bow shape at launch.. They actually add downforce in the form of a wing ont he nose to help keep the front end down, this was done as a saftey issue with all the blow-overs that were happeneing in the old days.. Then you have that rear wing further forcing the rear end into the ground. It's all about design. I am sure Jim's car will be a beast on the 1/4.
|I only mentioned the funny cars to make a point on weight not being necessary, not that I expected Larry to change his MG into a funny car. There are plenty of cars around with worse weight distribution than the MGB and weighing within a couple of hundred pounds of the MG that post good times. I still believe that suspension work to promote weight transfer would yield the best results. Larry has said that his car handles miserably, so adding lead to the back bumper would give the inetia moment of a barbell, not something you want in a car driven in coastal Washington|
|Suspension IS a key, I completely agree with that. I can attribute a large amount of my issues to poorly maintained original equipemnt on my car. I should have gone through it more cvompletely when I got it a couple years ago. Bad front Shock, exhausted springs and leafs, shot bushings and no front swaybar... Can you say PIG? It is about how she handles. But not for long!|
|Well, let's assume for a bit that we *were* trying to make Larry's car a real 1/4 mile performer. First thing we'd do would be to open the valving on one side of the front shocks so that the front end would lift on accelleration and stay up for a good while to transfer weight back. Then we'd add traction bars and set them up to plant the rear tires.(Of course these mods would cause the car to almost hop like a frog on heavy acceleration) We wouldn't worry about the sway bars, and we'd concentrate on the basics like fitting the car with drag slicks. Before long Larry's car would begin launching really well and his 60' times would drop like a rock due to the light weight of the car. It would be no funny car, but it'd be fun. At least it would on the strip. However, maybe Larry doesn't want that, I wouldn't. I used to have buddies who drove their strip cars on the street for their daily transportation, and I never once had any sort of urge to turn my MG into something like that.|
|HEH exactly Jim.|
I have a dream in my mind to make a MGB drag car. It would have to be a GT due to NHRA and personal safety rules.
Extremely tubed rear, ford 8.8 or 9", C4 tranny (no weight to ned stress for a C6) 302 block stroked to 347. Alum heads, high rise or tunner ram intake with big holley DP. Boxed in complete chassis with full 6+ point cage. stripped interior. remove stock gas tank, 5gal fuel cell. 10.5"+ drag slicks. 4link rear suspen, no swaybars. Front end modified to utilize a box shaped brace. like tower strut supposrts on a mustang to stop front end twist. homemade upper A arm to replace Armstrongs and install drag shocks. Maybe turbo the car, but probably just put it on the bottle. Maybe a roots blower STREET LEGAL would be a must, and to keep it looking like a MGB GT. 2 seats though very thin and striped type, 5pt harness for both, not a long driving car, probably a basic cheap AM/FM radio with a pair of speaker, mostly for hearing the radio broadcast at track and knowing when to get in staging lines. I would probably trailer it to track to, as when you play hard you do break and tow bills are not cheap from the track to my house. ASK ME HOW I KNOW!
This thread was discussed between 13/11/2002 and 19/11/2002
This thread is from the archive. The Live MG MGB GT V8 Factory Originals Technical BBS is active now.