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MG MGF Technical - EBD Exhaust Manifold (+15BHP !?)
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|You are not going to find 15bhp from an exhaust manifold! I have an Elise fitted with the EBD 4-2-1 manifold. This was chosen to provide better mid range and a bit of top end as compared to a 4-1 would provide. It's worth around 1-2 bhp top end but much more importantly around 5-7 lb/ft of torque gained low down. It works very well with Piper BP270's +|
I have some graphs showing power with exhaust, kn57, cat pipe, 270's with and without an ebd if anyone is interested. (Hope they back up what I say!)
>Whilst on the ramps recently, I also noticed that the >existing one is a rather poor Rover effort. :(
It is a nasty piece of work isn't it?!
|Richard, the EBD manifold doesn't offer a 15bhp increase, rather a 15% increase in Torque. Although this still needs to be proven on an 'F, its something that a few people on the BBS are looking to set up in the near future (myself as one of them). |
We would need a VVC as well as a 1.8i to do comparasion testing to see what the improvement is between the two models, we are still trying to sort out the details, but I'll let you know.
The other thing with EBD manifolds is that currently they are flexipipe-less, which may be ok on an Elise, but the F needs that flexipipe. The standard way would be to replace the cat with a flexipipe cat bypass, but this isn't always ideal. We're trying to get the manufacturer to make a version with the flexipipe fitted into the downpipe, as per the normal rover version, but we are unsure effect what this would have potiental gains - hense the desire to put a test together.
Could you drop me an email (addy above) and I'll fill you in with the details of what we have so far..
|I wonder what the effect of a flexipipe is on the gas-flow characteristics? I would have thought its "not good" as aren't they "ridged" (not having looked at it recently...)|
Would it not be better to get a manifold that actually ends up in the "right place" so it doesn't need any flexibility - the exhaust doesn't need to move about in use (and any movement that's needed should be providable by the rubber mountings). If its a case of being able to move it around to fit it in the right place, that's nothing that couldn't be sorted out with a "sprung joint", which is full-flow (and long life!)
Awaiting sage-like input from one of the engine-guru's (like Roger!) here....
|Neil, the flexipipe is there for a good reason, the engine does move around when in use and the movement if not absorbed, it would lead to failure. I think Rob Bell spoke to Tech-Speed about it and in their experience of the cup cars, which are flexipipe-less, they would eat through downpipes and manifolds. Remember that the engine in an 'F is not rigidily mounted to the car, rather it uses "soft" rubber mounts, so it does "move around" a fair bit. (I think the Elise is a bit more rigid and that's why they can get away with out one. (AFAIK)|
I'm no engine guru, or guru about anything mechanic when it comes to cars, the above is just as I remember it. Rob should be able to confirm / deny this as he has looked into this aspect of it in more depth than I.
|Steve C + Rob,|
Any nesw on getting this EBD manifold? I guess I would need a different design to you as mine is a mk2, am I correct in saying that?
|Ash, not sure, we need to check with someone first, I'm sure the exhuast system is the same on Mk1 and Mk2 until the cat, where it changes. So with that in mind, the pipe should fit both models.|
I need to sort a few things out before I can go ahead with the pipe, but it will be within the next few weeks.
|Neil, Steve has partly answered the question already- the chaps at Techspeed were very anxious about deleting the flexipipe as the Cup cars 'ate' flexipipes for breakfast, lunch and supper. This is why Mel happens to have so many spares handy!|
But I agree there may be some downsides to the performance of the manifold where the secondary pipes would need to be shortened in order to fit the flexipipe before the catalyst flange. This is why I'd like to get some RR tests done to compare the flexipipe manifold design with the companies own tried and tested design.
Might be fun to look at other manifolds from the likes of PTP and Mountune at the same time, but changing manifolds is SIGNIFICANTLY more tricky than exhausts. So I think that each manifold would need to be fitted to each individual car- and compare it with the standard item on each. Which is a long way of saying that we need to put in some considerable thought into how we design the RR tests to get the maximum amount of information!
Anyone out there with a VVC who may be interested in fitting an EBC manifold? So far we have folks primarily interested in fitting them to 1.8is...
You can always count on my interest !!
VVC looking for next mod
|I think Mel ended up being "sent" flexipipes as part of the cup-car "deal" - the reason he has (had?) some left is that Priest's car that he looked after DIDN'T "eat" them. I think they changed the exhaust spec a number of times while the Cup was running and he got sent a complete system each time and only used the bottom end.|
I would still be surprised if you couldn't provide the appropriate amount of movement for the exhaust with rubber mountings - or maybe by restricting the movement the engine can make at the top (I don't remember seeing a mounting at the top of the engine at all, though I could be completely wrong here - the Maxi I once owned [OK, OK, I know, it was a very long time ago...] certainly had a tie bar at the top that stopped the transverse engine from twisting too much.)
You never know, I MIGHT be swayable into making my VVC available for a header test - depends how much its likely to cost, and whether you'd want a (probably by then) 50k mile sample - its even still got a "standard" exhaust fitted! I remember how much difference fitting a "better designed" header used to make to m/c engines...
|Neil, I think that you're right that that is the reason why Mel still has so many serviceable spares. Nonetheless, Roy provided me a stern warning which I take on board (especially as I was concerned about the whole issue of engine torque reaction and the longevity of the manifold and flanges).|
To provide a little more bakground info, when I first started enquiring about these manifolds about a year ago I took advice from as many people as possible. Roger Parker for instance was reasonably confident that we'd be okay without a flexipipe based on experience with his extremely powerful Maestro T16 conversions. The chaps at EBD were essentially unsure. Elise owner experiences with the EBD manifold have broadly been very positive, with only the very earliest manifolds (which were made in a slightly different way to the current version) suffering from fractured welds. And this Elise experience includes some very powerful racing Elises in which one might reasonably expect to suffer engine torque-reaction.
So overall, the picture is slightly confused- and until someone tries the manifold on an MGF and can report on their experiences over a considerable period of time, I reckon most people will err on the side of caution and do nothing.
Hence the enquires into having manufactured a special manifold that includes a flexipipe. This carries a disadvantage in that it is an untested design, albeit one based on the current successful system. Hence the desire to get it 'benchmarked' against the non-flexipipe manifold.
The manifolds from EBD are works of art, and cost about the same as the stainless steel 'performance exhausts'- about 400 quid all in. Given that the performance advantages are about the same as (and in many circumstances better than) one of these exhaust systems, then IMO it is money well invested.
It'd be great to have both you and Dave on board for the tests- and I can keep you all posted as Steve and I work out the details. Maybe as a bulk purchase of 5 or 6 units we can get a discount? We'll see eh Steve? ;o)
Well done Rob & Steve.
Keep me posted--email address above if you've lost it.
|Yep, guys if you could also email me when you have some news, thanks|
I’ve just logged back on and I can see that this topic is on quite a few other people’s minds too. A few years back, well quite a few... :) I had one of these put onto an Astra 2.0 16V GTE and could feel quite a difference in torque, at the time I heard that the length of the 4-2-1 sections made a difference to the overall performance increases however I'm not quite sure whether longer or shorter was better or whether there was an optimum length.
A 15% increase in torque is got to be worthwhile. I have a MK1 VVC about 40K Miles and would definitely be interested in the group buy/test thing.:) Therefore please keep me informed at firstname.lastname@example.org
|Okay guys we'll keep you posted :o)|
Be patient, we've got a lot of details to sort out. Would you all be interested in buying your own manifold? attempts to get 'demonstration' manifolds have come to nowt in the past as they are only built to order :o( But we'll try to negotiate the best price we possibly can...
|A demo version would be nice :) although I'm sure they'd consider a group purchase discount - I'd be willing to pay.|
|Carefully tuned-length 4-2-1 does give significant mid-range advantages over a 4-1, this is a generalisation which can be applied to any 4-cylinder engine.|
I've done back-to-back tests with my admittedly rather highly-tuned K-series with a 4-1 exhaust (a good one with long primaries, not the nasty standard Rover one) and a 4-2-1 (which wasn't optimally lengthed IMO) and the 4-2-1 made a big difference in the mid-range. The plots are at:
The magenta line is the 4-1, the blue line is the 4-2-1. The latter is almost 20lbft up at 4250rpm. This was with no remapping or cam timing tweaks, so there might be even more to come.
Don't necessarily expect such big gains on a stock engine.
|Cheers Richie :o)|
|Guys, please excuse my ignorance, but I am interested in this. I was wondering (based on talk of the Flexi-pipe) if this is the sort of thing you're all talking about.|
yes, that is the flexipipe- incorporated in this picture with the down pipe. The EBD manifold replaces both the exhaust manifold AND the down pipe.
Mike- great graphs. Elaborates the difference between 4-2-1s and 4-1s nicely. Our stock engines will see significantly less power, but IMO the improvement in 'driveability' will be extremely worth while.
The ideal has to be some sort of test to establish any benefits. Perhaps we can encourage EBD to develop a prototype for testing by providing them with a list of 'confirmed' orders dependant on the outcome. I'd be happy to commit to that. Do you think they'd go for this?
|That certainly sounds like a good idea to me Dave- and is a direction that could explore further when we get to chat in more depth about what we plan for the tests with EBD. |
I *suspect* that we'll have to purchase one of each system at the end of the day based on my understanding of how the company works (it is very small, but clearly has considerable expertise- like many of the UK engineering companies).
It is very much a case of 'wait and see what we can negotiate'- but I will keep all of you informed of developments.
OK. Looks like there are enough people interested to find some sort of approach that shares the costs and establishes the way forward.
Leave it with you.
count me in for one.....
|Aye Matt I'm getting one too so you still won't beat me up Marlow hill :)|
I will if I un-dangle my k&n pipes!
I've found a cheap rolling road in Iver
if you want to compare VVC's
How cheap is cheap! I'd be interested to get my VVC on a rolling road. It has the ITG filter + Phoenix sports exhaust. Ivor is judt down the road for me too.
|Would 3 VVC's at Iver be a croud (if its not too expensive)?|
|Richie - Neil|
It was about 30gbp I think - I'll check again and let you know - email me at the above address and I'll give
you the details....
let me share my Elises experience with you and answer some questions about the EBD exhaust manifold and rolling road tests with EBD and standard manifold:
first , My Elise has 158 Bhp on the Emerald rolling road, and 138 Lbft .
head and valves flowed, cams, K&N, and Jansspeed exhaust.
I was looking for more torque and mounted an EBD manifold with flex. piece to replace the standard MG/Lotus one and went back to the Rolling Road 1 week later.
Result: NON ! no higher torque and no more Bhp.
Reason is, as Rob Bell says, that to make room for the flex piece, EBD shortened the secondairy pipes. (and the length of the pipes is essential for power and torque gain)
after a long battle/discussion with an very unwilling EBD, they finally replaced the flex. manifold with an early (rigid) design, of which it is proven on other Elises to give 10 - 15% more mid range torque.(I have not yet mounted and tested that)
problem is that the engine mounts allow the engine to move/tilt slightly (more after 5 years when weakened), while the exhaust is mounted reasonably solid to the chasis, thus giving stress to the system. that 's why EBD has developed a catpipe with flex piece.
Don't know if that solves the problem of cracks after 10-15000 ml
so in short:
-original -rigid-EBD manifold give 10-15% more mid range torque (depending on state of tune).
- Flexi EBD is no good for power and torque (they stopped producing it)
- to solve the cracking prob, try the flexi cat.rep.pipe.
|Bob van Melzen|
|Thanks Bob for your info. The problem is on the new cars, you cannot remove the cat due to a sensor in the cat, so the flexi bypass isn't an option :(|
And if the power gains vanish when the flexipipe is added, kinda negates the whole thing really, doesn't it. :( - Well, not for mk1 cars, they can remove the cat :)
there could be a solution to the problem if the manufacturer instead of a flexipipe made a "racing flexible joint ". Above my abillitys to describe correctly in english but works like a movable tube seated into a slight conical mating tube - all held together by several strong springs. Another thing would be to make the exthaust hinges supported from the sump/engine so the whole lot moves.. A bit like the old 356 Porsches and VW´s.But I guess the total weight of the system has to be lighter then...
best regards , Carl.
|Hi Matt / Neil,|
This sounds like a great idea and for 35GBP - could we do it at the weekend? Let me know when suits you guys? Rather than hijacking the thread you can mail me at email@example.com...
Cheers RichieR :)
|Bob, you may have just saved us some work there. Sorry to hear that the flexi pipe equipped manifold did not prove to be much cop. :o(|
It does sound as though we should concentrate on the standard rigid design as it is the best... What does everyone else think? It may be prudent to try it out anyway if only to confirm Bob's results with his modified head? Maybe that was a 'Friday afternoon manifold'?
I'll drop Graham an e-mail to sound him out about it. Bob, do you mind me mentioning your experiences directly?
|>"racing flexible joint ".|
Is that like you get in the exhausts of Opel's? They don't have flexipipes... (ordinary ones, not racing ones!)
|What do they have Neil?|
|Actually, I don't think it makes much difference wht sort of flexi-pipe is used if it compromises the length of the secondary pipes.|
The alternatives as I see it are:
1. Fit the flexipipe as a replacement to the catalyst. No use for me, as I have to keep the standard cat.
2. Modify the exhaust system to incorporate the flexi-joint (what ever it may be) instead.
The latter option is the most expensive- but is it also the best? It could incorporate the 'racing joint' that you mention Carl...
|Something very similar to what Carl said! |
The downpipe has a flange one it to receive bolts, and you fit quite a thick (cm or so) doughnut shaped ring (gaskit) round the end of the pipe in front of the flange.
The next pipe back has the end flared into a cup that fits round the doughnut ring. Again there's a flange, and the two flanges are held together with limited travel bolts that go through springs, thus keeping the joint under constant but limited compression.
(English is supposed to be my first language and I'm having trouble describing it !!!)
If I've totally confused you, let me know and I'll lean under a Vauhall at home and take a picture of what I'm trying to describe!
If it helps, that sort of 'compression' flexy joint is standard of my Peugeot 306 too.
It allows some give if the engine moves, but keeps its optimum form most of the time.
I'm sure the guys from EBD will know what the scoop is and whether that's a viable option.
|Might be useful that Neil- plus as many dimentions as possible. |
What ever flexipipe is used, it seems that it may need to be used after the cat as opposed to before it... :o/
|FAO: Steve C,|
>I'm sure the exhuast system is the same on Mk1 and Mk2 until the cat, where >it changes.
Looking at the WSM the whole system is different from exhaust manifold to rear exhaust section. A layout of both systems is present in the new FAQ....
|Thanks Paul the diagrams are good,|
Close study of each of the exhausts pre and post 2001 reveal that the exhaust manifold at the 4-2 section has indeed changed very slightly in exit from the cylinders. However the 2-1 section looks identical apart from the upstream HO2S mounting boss on post 2001 cars.
A really noticeable point is that the 2-1 section is incredibly short, surly a few inches extra length would release some torque... or better still 2 pipes all the way to the back box!
I don't mind you mentioning my name, just step back if you do so, he might explode.( he showed not caring anything about after sales service, so I had to "push" him a bit......)
I think that a solution is possible, though expensive. You can put 2 flex pieces in the 2 secundary pipes and keep them the same lenght.
But that's just thinking about it.
In Holland is a place where they produce flex. pieces in all sizes and shapes, so there should be a place like that in the UK as well I suppose.
I would suggest to put the solid exhaust on, and if it tears, then put 2 flex. pieces in.
a press-on flexi piece as described might work too, but it should be placed before the cat/catpipe, because the first bracket to the chassis is at the end of the downpipe, so from there is the "solid" mounting to the chassis.
|Bob van Melzen|
|I'm convinced that the length of the secondaries is critical - too short and you lose the effect. A fellow competitor with a similar engine spec. to mine has done back-to-back tests with a 4-1 and a 4-2-1 with short (~6") secondaries and saw very little effect. The 4-2-1 in the plots I posted has 12" secondaries.|
|Mike, this is very interesting as the standard secondary pipes look very very short and make up only about 1/3 of the total length of that section (D/Pipe) strangely enough they stop at the flex point. Which is perhaps the stress point rather than the ideal location for the 2-1 split.|
Perhaps we could design secondary (D/Pipes) that were much longer as the rest of the system looks OKish, did you find 12” as an optimum?
|12" was the length they came on the system that I'd borrowed to test. The optimum will depend on many factors, especially which cam profiles are used.|
|For flexibilty in the system look at ball joints that ave simple spring tensioning. Commomn on dozens of models, have more articulation that the type Neil describes and available in many sizes up to at least 75mm from exhaust specialists such as Jetex.|
I have some recent experience with the Janspeed/PTP Rover 200 that is badged as an MG. This engine has a fairly hairy tune inc cams of a spec I can't remember and the other mods include an EFI alternative engine managment system control.
With the standard manifold (same on all production 16V K series for some years now) and a standard downpipe, which has longer secondary pipes than the F, the effects was a sweet revving engine with a good power spread.
A very special 4-2-1 system was made up with very long primaries, of about 24" and about 18" secondaries. The effect was stunning and destroyed the mid range driveability! The upset was so severe a remap was needed and rather than try and work with the existing system the owner went to see Dave Walker and has an Emerald system fitted.
What a difference this has made. The car really now has a softer idle and a huge imcrease in torque in the mid range. Without needing to measure this, it is so apparent and is on top of a wheel and tyre change that has lenghtened the gearing slightly.
The luxury of this car is that being a FWD layout there is the room for the pipe lengths. There is no way this is available on the F or Elise. Top end power is not apparently any different. Rolling road results do confirm these feelings with a big icreease in the mid range and a lowering of the peak torque point - effectively widening the usefull power band.
This thread was discussed between 09/10/2001 and 13/10/2001
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