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MG MGB Technical - Have I discovered something? Exhaust Pipe Wrap!

Several things going on here. Like any normal healthy 65-year-old MG boy, I wanted my '73 B/GT to go faster, so a week or two ago I installed pertronix and MSD ignition. The MSD made a notable, if not stunning, difference and I concluded that it was $180 well-spent.

Also, like any normal healthy 65-year-old MG boy, I wanted my '73 B/GT to be more comfortable so I installed A/C last spring.

Now the A/C has worked quite well, but I've been making continual improvements in insulation to make it work better. So, about a week or two after installing the MSD, I wrapped the exhaust pipes from the manifold on down to the first muffler. Certainly, I wrapped those downpipes initially only to reduce heat. Significant reduction in engine noise was an unexpected but welcome benefit. Recently, I've been scratching my head recently trying to figure out why the MSD seemed to have gotten a lot better recently. Then it dawned on me, the header wrap on the exhaust pipe!!!

I have a somewhat objective, although "sub-scientific", power criterion - a long hill on my way to work which I approach from a dead stop at the bottom. A well-tuned stock '72-74 MGB simply will not accelerate beyond about 62 mph on this hill. I built a bit of a souped up '76 B a few years ago that would get to 70 by the top. Before MSD, my current GT would do about 60 at the top. No more. With MSD I could coax 65 or 66 out of it. But about a week ago I noticed I can now pull 72-74 mph out of it by the top. I did it again this morning. Nothing else has changed at all - could it be the wrap on the exhaust pipe?

If it is, this is one VERY easy way to significantly improve the performance of a stock MGB. I can't figure out why everybody doesn't do this. So, beyond spreading the good news, I'm writing so that those who know more than I can tell us what the downside of this is. Certainly it's not gas mileage. This car gets an easy and consistant 30-32 mpg on the highway and it certainly hasn't gone down any. Is somebody about to tell me I'll overheat and burn out an exhaust valve or four? Will the heat blow out my mufflers? (If so, that's a fair trade off!!)

What am I missing here? Why isn't everybody doing this?
Your mileage may vary... yada yada yada...

FWIW
Allen




Allen Bachelder

There was a discussion on the mga twin cam BBS not too long ago and one issue that came up from a number of listers was the trapping of moisture and the resulting rotting of the pipes. A bit more expensive for an exhaust header on a Twin Cam than our B's so perhaps its not as big an issue on a B. That's all I know 'bout that. Cheers,

Paul
Paul Hanley

Allen- There's a lot of Board VooDoo-Doo regarding exhaust wrappings and attendant warpage since Peter Burgess'comments. I think your story is fascinating. Hell, son, you've gotten a nearly 20% improvement in top end speed under load! That is stunning stuff!!. Can you re-detail the improvement after wrapping? What type of wrap? Did you jet hot coat anything? Is your running temp on the gauge the same? Vac advance or no? What port? Advance curve on the dizzy? Used unit at $180?- the new ones are closer to $300 aren't they? Congrats on the great story. Vic
vem myers

Allen, do you know what the advance curve is on your distributor? No vac advance, right?

Have you checked to see what your cylinder pressures are? I would suspect over 200psi. It would be interesting to know!

I had my header wrapped for a couple years. It didn't rust or rot the header at all, and its not warped. I only removed it after a valve cover gasket blowout had saturated it with oil.
Jeff Schlemmer

Awesome... Im going to do the same exact thing, moisture being trapped in the pipes ? Wouldnt the temp be hotter in the pipes and a result of a lack of moisture, and with Stainless steel pipes would it be a problem ?
James

Hi Allen,

I reckon you could do a couple things.

a. unwrap the damn pipe and see if your speed goes back down.

b. check your speedo for sudden calibration wackiness.

c.recognize that you're a genius, receive the accolades of your peers and let it go at that.

Art Dodge

I'll have to get back to you guys after I check for a couple of answers to Vic's questions. This is a stock 18V engine, only I added 18802 pistons and a "BL-1" grind cam on last rebuild. It was nice, but quite underwhelming until MSD and - mind you - NOT a wrapped header - but a stock manifold. I only wrapped the exhaust pipes from the manifold to the front muffler. I am running the stock 25D with vacuum advance ported to the intake manifold. Did HIFs ever come with vacuum ports on the carb itself?

My MSD ignition is an MSD 6A model 6200 which I bought from Summit Racing, new, for $179.95. The Exhaust Wrap is made by DEI (Design Engineering, Inc.) of Cleveland Ohio, and marketed through Advance Auto.

Vic, I don't know what Peter Burgess said about wrapping, but I wonder if it would apply to wrapped exhaust pipes running from an unwrapped stock manifold.

This is a total shock. I did the wrapping only to insulate from the heat and make my A/C work better. It makes a huge difference in sound levels also.

So far, it seems like a win-win-win situation!

Allen
Allen

Art,

I'm not so curious as to want to undo and redo the whole thing. That takes care of #1.

My speedo/tach relationship remains unchanged. So I doubt that it's the speedo. What's the likelihood of both of them independently going whacky by the same amount at the same time? That takes care of #2.

If this was the result of any design on my part, I might be tempted to claim genius, but the best thing I can do is claim that I was there when it happened. No accolades sought or deserved. There goes #3.

That leaves me waiting for James to try it and see if he has a similar experience.

I know that different sets of springs and weights were available for the 25D4, but I don't know what's on this one, nor do I have any particular reason to believe that they are original. I do know that the combination was manifestly unimpressive before MSD and exhaust wrap. I'm still not going to keep up with a 2-litre, a supercharged car, or an MGC in reasonable tune, let alone a V8. It's just become a lot more fun.

And I don't even have the Burgess head yet. That's next...

Allen
Allen

It's pretty simple really. The exhaust wrap is insulating the exhaust and therefore less heat is getting into the inlet manifold. The cooler the inlet air is, the more power, which is the reason turbo cars use intercoolers.
dave

Dave- Care to expand your simple thesis. Vic
vem myers

Dave,

A website for the wrap mentioned:"Wrapping headers maintains hotter exhaust gases that exit the system faster through decreased density. Increased exhaust scavenging is produced, along with lower intake temperatures." Check it out at:

http://www.jscspeed.com/index.html?/universal/thermotec.htm

I just wasn't prepared for the amount of difference this makes.

Allen
Allen

I still have the Cat on my exhaust, what do yo think about wraping that? Not buying a new exhaust system till summer comes around again, and yes it is a very simple thesis about cooler air going to the carbs, you guys want to get the cold air box discussions going again ? This is just a curiosity I have always had, what if you always had your ac running in your car but connected the ducts to the intake of your car ?
James

Allen,

Your experience is very interesting. Having your personal test hill that you use often is good.

There may be a couple of additional factors here.

The benefit of the MSD could be two fold. Firstly when setting it up you will have corrected the ignition timing which will have moved from its previous set due to wear of the points etc. Secondly, the power of spark declines as the revs increase due to the coil having a shorter recovery time. Most electronic ignitions put more power into the coil so a more powerful spark comes out. So at any revs you should have a stronger spark than before. This tends to be most significant at higher revs.

You fitted the exhaust wrap to improve insulation. While heat was your concern it will have also reduced the sound. Most of us drive by ear especially when it comes to gear changing. So I suggest that, while the wrap may be increasing power at a given engine speed, it is probably causing you to use more revs in each gear. This will enhance the acceleration significantly.

David
David Witham

Header wrap was praised when it first came out for use on 'street' cars, however, it has been found to not be friendly to header pipes. The constant heat cycles crack the pipes as the pipes get very very hot and fatigues the metal. The better way to do it is to have the pipes coated by JetHot or any other company that does the same thing. The coating keeps heat inside the pipes but not so much that it cracks them.

Header wrap on race cars is fine because they don't experience the number of heat cycles a street car does.
Mike MaGee

FWIW I found the exhaust wrap did indeed help keep the inlet side of things cool and encourage the engine to produce more power, and it reduced heat soak when stood in traffic.

It did also cause the tubular manifold to crack at the weld joins between the pipes.....I can only surmise a combination of moisure and extra retained heat, especially as you get a bigger overlap of the wrap at the point the tubes all join together. After the second scrap header in 2 yrs I looked for an alternative, and had the pipe ceramic coated. 2 yrs on and the 3rd header is still just fine.

Remember too that the wrap makes a great wick if you have an oil leak....
Chris Cooper

Chris,

Where was your manifold coated?
Alexander M

I've had wrap on my V8 manifolds (headers to you) for years, primarily to reduce under-bonnet temps.

The cooler(denser) the air entering the engine, the more power you get, I did see some figures which suggested that the gain was very small, but I have no means of comparing as both my cars have lagged exhaust manifolds.

I have never experienced any cracking problems ( stainless manifolds in both cases), the V8 is lagged all the way to the end of the 'Y' pipe ( I have RV8 manifolds). The footwell is considerably cooler than when I had the standard BV8 set-up, but there is a lot of heat coming out from underneath the car when I stop .


Mike
Michael barnfather

Mine were coated by http://www.zircotec.com/
who are near Oxford.

rgds
Chris Cooper

Any idea how much Chris, if you don't mind me asking? The DCOE on my car tends to cook in the summer so this sounds interesting.
Steve Postins

In UK also
http://www.camcoat.u-net.com/

Paul
Paul

I had 2 MGC 3 into 2 tubular headers done....cost about £200 I think, over 2 yrs ago......
rgds
Chris Cooper

I already have jet hot coating on my peco header & don't want to wrap it, necessarily. But I've always had (way down) on my to do list a large diameter flex hose from behind the grille to feed the carbs and even fab up a cold air box. I am now even more inspired.

The quieter in-cabin exhaust/higher shift point/higher on the power band mental trick speculation is intriguing.
(Daily prize contender for uber compound sentence).
Art Dodge

Yes, quite an artful dodge I'd say, eh? Besides JetHot Coat in the states, who has the better bang for buck in ceramic header coat? Vic
vem myers

Vern,
My Dad, Bob N., had a sense of humor.
Art Dodge

A- You'd think your pappy's last name would've been Weaver! Anyone with bang for buck ceramic coaters? V
vem myers

David,

Your arguement about shifting by ear, and now hearing less, I've unconsciously moved my shift points up is interesting and quite plausible.

But when I'm trying to get the most out of an engine, I do keep my eye on the tach and I don't seem to notice any difference in my driving habits. Also, under these circumstances I tend to shift when I feel I've milked the last out of the power band in any one particular gear. Quite coincidentally, this morning another vehicle blocked the passing lane on my way up the hill this morning; I gave up trying to set my personal land speed record, just dropped into fourth at about 3000 rpm and let it roll as it would. The offending car moved out of the way, and by the top of the hill I was still going 68 mph - faster than the car would go on the MSD before the wrap.

So, I'm inclined to dismiss that argument.

Allen
Allen

I'm know I'm reaching maybe more than a little here, Allen, but stranger things have happened.

Plate Tectonics. Your hill has become flat.

OK enough foolishness. In my highly undereducated but extensively shade tree experienced view, the underhood temperature has gone down enough so that the charge is more dense with oxygen. It makes you wonder what the mixture has been throughout the entire exercise.

Also, we are heading into autumn. From my flying days, there was a marked difference not only in flight characteristics in a light plane in the fall/winter but also in throttle and prop response. In the thinner, hotter summer air the plane was lazier all around. Winter it was almost frisky. This is everything from a 2 place Ercoupe to a 300 horse Stinson Reliant. You may be benefitting somewhat from denser, cooler ambient air.

Again, I am frantic now to make an airbox and ram tube. There must be at least 75 horses lurking out there just above the front bumper.

Art Dodge

Allen,

Appox calcs suggest 1bhp for add 1mph gain 15bhp
1bhp extra for 3c drop in temp

Autumn weather plus cooler intake will add bhp.
The wrap will help gas flow out and may help with reflected pulses which are at speed of sound.

The downside is that the heat is now trapped by the wrap and manifolds could be near molten.

Whatever the reason it works so enjoy.

Paul





Paul

Paul and Art,

Well, I have spare manifolds... The theories about cooler autumn air just might apply around here. Perhaps that, compounded by temperature drop caused by the wrap, is creating a noticeable difference whereas either one by itself would be below the threshold of noticeability. (If that is a word!)

Once again, folks, I do not have a header - just a (molten?) manifold. The wrap is just on the exhaust pipe. James asked about wrapping a cat. I tried that but she fussed so much and kept biting me - so I gave up.

Perhaps someone else will try this and comment on my experience. For awhile I was wondering if the MSD just took a few hundred miles to program itself. I confess I have no idea what's inside that red box. I do know it delivers about 100 volts to the coil and I know it delivers multiple sparks below 3000 rpm. Although MSD recommends experimenting with spark plug gap (up to .050), I have not tried any bigger than .035. At any rate, it's going very well these days so I'm taking Paul's advice and simply enjoying it.

Cheers,
Allen
Allen

Allen,
Is this hill near one of those "Ley Lines"?
You know, where bowling balls roll uphill during weird moon cycles? ( saw it on Discovery channel )
I'm dying to try this along with NY James, yet I tend to run a little hot as is down here, you gents at least have more temperant ( read "humid and cold" )
weather.
Jim.
J A Kelly

Hey Jim,

You may have explained this whole thing. Tomorrow I'll stuff a "he-frog" into the carburetor and see what that does. I feel like I'm moving into the 5th dimension. If my future notes sound increasingly incomprehensible, you'll know that me and my MG have entered the "Twilight Zone". I'll be back in the year 3506. Stay tuned. It will seem like tomorrow to the rest of you "Earthlings".

Allen
Allen

I'm with Paul on this. My rolling road technician pointed out that every 4 degree celsius drop in the intake temperatur would increase power by 1%. Therefor wrap might be advantegeous(sp?)in cooling this air.

Regarding warping I believe P. Burgess comments might only be true for the steel tube headers and not the cast original and its corresponding exhaust pipes.

I don't even use a heat shield under my HS6's and I probably loose a good deal of power that way. I'm currently in the process of making a heat shield and a cold air intake for the car.

Currently with HS6, sticking dizzy and Peco HDR exhaust I managed 74 RWHP and 66 FWHP ontha rolling road - so plenty of potential to go better :D
N.C. Nielsen

Are there any Europeans interested in a 'group buy': if we can come up with a couple of people who want to have their manifolds coated, the price will probably drop.

Just an idea of course...
Alexander M

Paul.
The only time I ever got exhaust manifolds seriosly hot was when I grossly mis-timed a Frogeye sprite in my youth, the tubular manifolds got to cherry before I worked out what I'd done !

I have heard stories of cast manifolds cracking, but I would not have thought that a little wrap would make that much diffence to gas temperature, and nobody has actually confirmed it, these forums are often more full of theory and opinion rather than facts.


Mike
Michael barnfather

Wasn't exhaust manifold wrapping identified as a cause of detonation in a recent thread? I can't remember why its a bad thing though, unless it just keeps head temperatures up.
Stan Best

I tend to go overboard like putting dielectric grease on any electrical connection I could ever find in my car, so what do you think about wrapping the intake manifold, should get the air temp a little colder, and a cheap easy way to get colder air is to set up a very simple cold air box by running some flex pipe to the carbs. Maybe you can do some more experimenting, run the car with the air filters off with a jerry riged cold air box, just use some duct tape to make a decent seal around the carb intakes and run the pipe to the front of the car, as a quick easy experiment, also try ram pipes. That definetly would decrease air temp a few more degrees and we can see if this theory is correct, you should be able to squeeze a few more hp out of her.
James

Alexander,
I would be interested in coating of the manifolds of my CGT, but wonder if the coaters are going to be impressed.
A few weeks ago I had the opportunity to the CGT on the Zandvoort circuit with, among others, a Speedwell Sprite and a Porsche 911.. very amusing to see the Sprite go faster then the 911. The Sprite had a coated exhaust manifold and Megajolt ignition, guess what I want..
Rufus
Rufus Pool

Mike

Although the pipe can withstand the temperatures of exhaust gases, when the pipe is not allowed to cool and dissipate those extreme temperatures by using wrap, you have developed a heat absorption system which will will continue to gain in temperature beyond the normal exhaust gas temperatures.

From previous discusions I do not think this is so much of an issue with SS because less heat is being dissipated in the first place to be trapped by wrap. Hotter manifolds may tend to feed heat back into head and potentially also cause warping as found by PB.

In theory SS has a carbon content and this can cause the stainless to become susceptible to corrosion at high temperatures. When chromium-nickel steel is heated to a temperature range of 800° to 1590°F, the carbon in the steel combines with chromium to form chromium carbides. This transformation is called carbide precipitation and reduces the corrosion resistance of the steel. The chromium is reduced in this heat-affected area and makes the steel subject to what is known as intergranular corrosion. Some stainless steels are known as low carbon grades to minimize this carbide precipitation or are special alloys that reduce carbide precipitation by combining and stabilizing the chromium at elevated temperatures ie the problems can be avoided by using correct materials and in F1 Super SS is used Inconel. Chris's weld joins may have been a weak point in system and perhaps also double wrapped.

Paul




Paul

What am i doing wrong??
My mild steel header on my 64 MGB is coated with wrap from the head bolts down to the y-pipe. I did this sometime in the early 80ties and have driven the car at least 100.000 miles since then. Still no cracks and no rust on the manifold. What´s wrong????
Joern-M.

Vic:
As to your question about "bang for the buck ceramic coaters", see the site below. I bought their water based coatings and did my own headers, combustion chambers and pistons (ceramic tops and dry film lube skirts).

http://www.techlinecoatings.com/

Phil
Phil O

Joern,
DO NOT unwrap the wrapper! Your header has vaporized!
It's like the Invisible Man if you unwrap it there'll be nothing!

AAARRRRRGGGHHH!!!!!
Art Dodge

now if you wrapped your intake manifold with something like asbesdos, it would act as a heat shield and not a heat insulator? or does the open air let the heat dissipate faster from the intake manifold, stupid question but just curious (I swear im so much smarter than this !!!) I have the stock 79 int-ext which obviously is horrible, im just curious about what you can do to disipate heat from the head to keep the air cooler when you get it to the head from the intake, obviously cross flow head is it(Or just junk it and buy the V8 etc etc) but id rather pay off my studen loans first ! What can I do
james

answered my own question a second later at the techline coatings site, pretty cool !
James

Quoted from the same site... For all of us too lazy to click the link



There are a variety of reasons for coating an exhaust manifold header. #1 Corrosion protection. The manifold will live longer as well as look nicer. Whether it is for performance or show, coating an exhaust manifold is valuable to you. #2 The coating is a thermal barrier, thus keeping heat within the manifold or header. There are a number of benefits for this. First, by keeping heat within the manifold, you're going to acc elerate the exhaust gas velocity which reduces back pressure and reduces fuel contamination due to reversion. This is a performance benefit. Second, you'll reduce the surface temperature of the manifold. This means if a person comes in contact with it, they are less likely to be burned and leave skin behind. If there is a component close to it, it will not see as much heat as it would with an uncoated manifold. In addition, not as much heat will be radiated under the hood or into the engine compartment. This reduces the underhood temperature which, again, reduces the temperature of surrounding parts, such as, alternators and starters. It also reduces the amount of heat that can be drawn in through the carburator, which is a secondary performance benefit. There are a variety of coatings that can be used on exhaust manifolds or headers.
james

Couple of points to consider

Speed of sound changes and therefore effect on pulse tuning?

heat is expansion of a gas - what happens on cooling and flow restrictions.

Also corrosion- convential water rust?

Another question - heat has to go somewhere - coatings move heat to someshere else?

Paul
Paul

This brings to mind loovers. There's a reason they put those vents on the fenders of the old buicks and the newer Mercedes. Its why they put them on the hoods of hotrods. Let the heat out.

I remember the kit that would offset hinges on the hoods of VW bugs to let heat out. What cars (I know I've seen them) have the huge hood opening just behind the radiator? The heat from the radiator blows up and over the hood instead of onto the motor. I think it is Ferrari or something.

I've seen a local with a ford 302 in his Jag XKE and a vented(louvered) hood. Its been his daily driver for years.
Maybe a couple slots back by the hinges would make a difference on a B or a vent on the fender just infront of the driver's door to let heat escape.


kids1

Kids,

You mean the left hand door, don't you? :-)

The Porsche 911 GT2's and some more indeed have vents behind the rad...
Alexander M

TR2's and the 3's had small slots back by the bonnet hinges and the Triumph GT6 MKII's had louvers on the top and side skirts of the bonnet maybe Triumph DID know something after all
Jeremiah Randolph

Kidsl,

I've folded back the centre part of the lip at the rear of the bonnet, and cut out part of the channel on the scuttle, this gives quite a long slot for the hot air to escape, I've got an RV8 bonnet, but I think this would work with the MGB one as well.

I've also got louvres a la E type on each side of the RV8 'hump'with small computer fans wired in with the radiator fan, which suck hot air out of the engine bay, aluminium V8 engines get quite hot when stuck in traffic, and I can see heat haze from both the louvres and rear of the bonnet .


Mike
M Barnfather

The louvres issue is a little counter intuitive.

Louvres and air vents close to the windshield are in a very high pressure area at speed and will actually force air into the engine compartment.

Openings to pressurize a carb should be towards the rear and facing to the rear.

Openings to vent the engine compartment should be in the forward part of the hood where there is a low pressure effect at speed.

Barry
Barry Parkinson

Alexander, You are correct. I meant left side. In the US frame of mind so long.
kids1

Yes, Barry outer bonnet pressure is high. But the louvre profile creates a depression in its outlet area, and the inside bonnet air pressure is not that lower as the outside: remember on this BBS the slightly overheating MGA story whose driver incidentally removed the gear dipstick rubber plug, the dial temp. decreased
as the inside hot air stream inveded the car. And back to Triumph, yes the back bonnet ridge is slot opened to give way to hot air.
Back to the jet hot coating, It 's contributing to improve hot gases outflow and is decreasing the lower bonnet temperature so far it improves performance by not disturbing the fuel/air ratio.
Renou

Barry.

I've heard that theory propounded before, the purpose of my louvres is to exhaust the heat at standstill, engine temp drops to normal within minutes of getting on the move again.

Mike
M Barnfather

NC- I've found no heat shield is required when the HS6's are mounted to the cross flow manifold/head ( he he he). I wonder if wrapping that 2.5 inch Han's Header (which came silver ceramic hot coated), would be worthwhile..... Vic
vem myers

Keep in mind that if you manage to pump hot out of the engine bay through the back of the bonnet, it's going to go IN you fresh-air vent! Hope you don't have an exhaust leak! ;-)
Rob Edwards

Rob,

Believe you me, if you have a leak on a V8 exhaust manifold, you hear it immediately on start up !


Mike
M Barnfather

Before you all rush out with the tin snips just remember that in many parts of the world you wont get a road worthy cert. if your seal along the rear of the bonnet (hood)is not intact. Allan was carefull to say that he wrapted the down pipes and not the manfold. One advantage (the only one)about being a senior citizan is that i/v seen it all bafore. Dont use it on a manfold as it will warp it. Wont notice it until you take it off for some reason then try to put it back.It will be like a banana. It is interesting what Allen has to say about his performance increase, I too would like to see it removed to see the difference but its a bit much to ask. We used wrap on hotrods back in the 60s to keep the prying fingers of passes by safe. I never heard of it increasing performance but we sure had warpage. The cast manfolds were the worst. I myself tend to think Allens gain was a result of replacing a sick ign with a top class one. All the best Denis
DENIS H

Increased exhaust scavenging was mentioned above which relates to negative pressure waves, the strength and reflection is based on manifold system 4-2-1 or 4-1 etc but the speed is speed of sound which increases with higher exhaust gas temperatures and therefore has an effect on scavenging.
Paul

Hello,
I just received the PECO header and exhaust kit from the Proper MG for my 67' GT. Tomorrow I am delivering the header to a local Jet Hot coatings company.
I will post the results after installation.
Steve
Steve Brooks

Steve, do you currently have an uncoated PECO system on the vehicle to compare it to? I love the performance and sound of my PECO system but I am comparing it to the old manifold and damaged exhaust.
kids1

It's fun to see that this thread has generated a life of its own, and I've learned a lot in the process. I had been tempted to take the carbs and intake off to see what I could do in the way of wrapping the manifold, but I have definitely been talked OUT of that!

For the most part, I agree with Denis. My gain was, no doubt, largely due to the ignition update. However, it appears that the wrapping complimented it rather alarmingly. I'm not claiming a huge boost in power here, but there was a measurable change (my test-hill) when, after I had installed the MSD, I wrapped the exhaust pipe. Since I did this only for insulation purposes, the boost in performance was a delightful bonus.

' Hope we all continue to enjoy and learn from this thread. Thanks, all!!!

Allen
Allen Bachelder

Kids1,

Currently, just a stock manifold and Monza system which has blown out the wadding and is way too loud, especialy on the highway.
The Jet Hot people were great and showed me some examples of the coating in the showroom. The silver is awesome, so that is what I'm getting.
Quoted price $165.00 plus tax and I'll have ut by Monday.

Regards,

Steve
Steve Brooks

I think that any of us who have had B's for years know that the cars go more quickley on cool air days. Would somebody design a cold air box and then post it?
JLG Galbreath

" So, about a week or two after installing the MSD, I wrapped the exhaust pipes from the manifold on down to the first muffler" Allen- Perhaps you have another 15-20% gain ready to unfold if you jet hot coat that ( what?) stock cast exhaust manifold! Steve- We'd be interested- I'm sure- in your seat of pants evaluation re your hot coated GT! Vic
vem myers

JLG.

I fitted a cold air box on my V8 conversion, it's ducted from a vent in the spoiler, through the triangle formed by the chassis rail and inner wing (next to the radiator) into a box which has a PiperCross filter in it. It might be more difficult for twin carbs, but would meathat your'e not sucking in heated engine bay air.


Mike
M Barnfather

Hey kids, I'm looking into it. I've found websites for Techline and Jet Hot Coat. Which one is better? I'm also looking into:

1. K & N filters

2. Combining K&Ns with a cold air box of my own design, drawing air in directly from the front. I'll have to learn about conical designs and the benefit in terms of ram effect. (I'm a trumpet player; you'd think I'd already know of such things.)

3. Installing a Peter Burgess "Econotune" head. That will be my one major expense - but still small potatoes in the realm of performance enhancing goodies.

Oh yes, that's hardly a tip of the iceberg in the business of tricking out a "performance engine". But it's about as far as I want to go. So far, my expenditures have been VERY reasonable and I'm very happy with the results - both expected and unexpected. Yeah, I know, the guys with the $3000 Moss superchargers will still blow my doors off, but as long as I feel something happen when I put my foot in it, I'm happy.

Right now, I've just "discovered" third gear. Going up my test hill, as well as others, my third gear takes hold around 3400 rpm and then it just seems to go and go. I'm not sure I've found the top end of the third gear power band, but it really feels strong (compared to a stock '73) up to something well past 4500. It seems to be coming on right about the time it used to give out.

Bear in mind, guys, that while I've been around, and into, these cars for a lot of years, I'm pretty naive when it comes to seriously making them go faster. Perhaps a lot of you would be pretty unimpressed with this car that's now thrilling the daylights out of me. I guess that's the beauty of having relatively low standards: one is easily pleased!

But perhaps now I'm incurably afflicted and I'll just keep on doing "just one more thing"...

Cheers, all,
Allen
Allen Bachelder

Allen,

As a trumpet player this may be amusing!

http://www.mgcars.org.uk/peterburgess/flugelhorn.html

Good info on Minimania site Calvers corner although on A similar issues.

Paul
Paul

Hello All,

The Jet Hot guys called me today and the header is done a day early!
I will not be able to install it until next weekend though, as the local MG Club is having their car show Sunday and Saturday is tied up.

Regards,
Steve
Steve Brooks

Paul,

Yeah! Now my MG and I will be able to play duets together. Of course the MG will be sucking on the thing. But some musicians I've worked with might argue that I do the same thing! 8^)

Steve,

I just got an e-mail from Jet Hot. The prices seem very reasonable. I have some spare manifolds here - if I have the right one, I'll send it.

Allen
Allen Bachelder

I can't see wrapping the exhaust pipes will make a great deal of difference to the underbonnet temperatures of a car moving at speed, it will certainly help in heavy slow traffic, but if a car is travelling at say 60 mph the cool air is entering the front grill at 60 mph [assuming calm weather for simplicity] it's going to remove the heat very quickly as it exits down the gearbox tunnel at 60 mph??
Ron
R. Algie

Ron,

The problem with my V8 is that there is no room for the heat to exit the engine bay unless the car is moving quite quickly, there is no room around the gearbox, and the alloy engine and plenum chamber soon build up a lot of heat when it's sttod still....temps drop to normal after about 2 minutes at motorway speeds, but the heat build-up can be felt in the footwell (even in a roadster) for some time after....not much fun in summer.


My system's lagged right past the 'Y' pipe to under the passenger seat almost.

Bear in mind the V8 engine puts out twice the power of the 1800, so bound to be loads more heat produced as a result.


Mike

M Barnfather

intresting webpage pete, I guess its like designing a perfect pour spout, its imposibble, didnt know about the resonance of intake tubes and standing waves would affect it. Acoustical engineering for air filters ! You guys ever hear of an acoustic refrigerator, do a google search, it refrigerates using a speaker !
James

I have had two experiences with the header wrap. One on a 74 B that eventually did crack apart the exhaust manifold after 10 years where they intersect and another on my 1300 Sprite. The Sprite being different in that it has a header and a 45DCOE. I found on long continuous speed drives that I had icing in the intake manifold, so I unwrapped the header some just enough to allow some heating of the intake manifold and the problem disappeared.
mwhitt

Anyone got news on power increase re:jethot? Vic
vem myers

Well, I guess the gusto in this thread is plum run out! V
vem myers

This thread was discussed between 19/10/2005 and 12/11/2005

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