exhaust manifold

[dblenk]

Come on Guys this isn't the place to drag up old grievances.

 

I think the debate has raised a few issues:

 

Which of the currently available exhaust manifolds is the best?

There probably isn't a single answer as this does depend on other factors such like modifications to the head, CR, camshaft, filtration and the exhaust it's mated to.

However if one was so much better than the others why don't we all know about it by now? Surely shed loads would have sold in the 40 years since the 6 cylinder TRs were launched.

 

Why are tuning parts so expensive? How the manufacturers of items like exhaust manifolds justify the price they charge? The manufacturing surely can't be such as to justify a £1000 price tag? Is there that much more assembly work involved with one manifold compared to another. A bit more welding, a bit more complicated cutting & bending perhaps but how much are these assembly workers paid?

The design work certainly has a price tag but how many "man hours" go into it? What is the time frame to recoup the design costs?

Perhaps greed comes into it and the short short term mentality that afflicts Britain - sell a few at a high price rather than a lot at realistic price? Knocking up exhaust manifolds for TRs is not the same as designing the ultimate for an F1 car and the people doing so surely can't delude themselves into thinking they are in th David Beckham league in terms of income.

 

20 years ago when I first got my TR there were so many more companies in the TR game than now and you just wonder how many of those would have still been trading if they adopted the philosphy of "this is my job for the long term". More grease monkey than city trader!

 

Does anyone truly accept that the true cost of half a dozen manifolds could equate to the cost of a new car?

Just because an old tea cup sells for a furtune at an auction it doesn't mean that a new one, with a more refinements will fetch more than a few pence even if the designer has put a week, a month or even a year's design effort into it!

It does seem that mark ups in the classic car world are substantially more than in most trades.

 

exactly andy

i thought i knew what i wanted but as the mods for under a £1k have not been published on teh forum, i am going to fit an induction kit to get the air to my dellortos, then fit the 6-3-1 manifold from pheonix, then sort a cam and head stuff if required, fitting one at a time, i will be able to monitor the improvements, i dont want a racer just more fun , i recon these mods should cost under the £1K ?

regards

david

[Andy Moltu]

It comes as "shocking" that somebody claims intellectual property?

Wow really?!!??

 

Did you attempt to patent your design? & if so did you make any claim agaist those that copied your design? 25 years on the patent is expired I presume.

 

Paying £50 an hour for a fabricator welder does seem a lot (£90k a year less overheads) Perhaps not in F1 circles where perfection immediately is required but for a production run seems a lot. Whilst your design may be better than say a Phoenix one does it really cost 4 times as much to make?

 

That's a reasonable question and not intended in any way as a personal insult. 25 years on is a bit too long to be factoring in your design costs.

 

Incidently I've had a passing interest in TR racing for 20 years and have looked under many a bonnet and seen all sorts of manifolds.

[Andy Moltu]

In the UK with all the stuff and overheads, and running around, making flanges, and having problems of one sort or another that gives a very skilled guy a BARE 2500-3000£ a month to live on.

That's still £30-36k a year which is probably more than many.

 

Presumably that's why so much industry is moving out of Europe & to South Africa, Eastern Europe, China, India & so on.

 

Playing Devils Advocate here are you certain that some of these manifolds are truly copies of your design rather than attempts to better the design (be it from a performance point of view or an ease of manufacturing) - after all there are only a limited number of permutations for a six branch manifold.

The exhaust ports are fixed by the head design and the mating with the exhaust is largely dictated by where the exhaust has to run.

The permutations are limited to 6:3:1 or 6:2:1 if you discount the 6:1 as being a practical nightmare to produce from tube.

Taking the 6:3:1 which inlets go to which 3 again would be dictated by the firing order. How and where the primary pipes run is greatly constrained by the chassis, engine and steering column on a RHD drive car. (The pipes have to go either between the engine & column or loop round the outside & there probably isn't room for all six to do this so I assume this can be varied from design to design. The lengths of the primaries are probably also constrained by the space available which assuming the curvature need to be as gentle as possible to avoid restricting flow and the practicalities of bending the pipes and bringing them together in such a way as to enable welding & exhaust clamping.

 

The upshot is that if you put 20 exhaust designers to this task it wouldn't be wildly suprising if a number of them were broadly similar looking. Some may well perform better than others. Clearly there's no excuse for making a blatant copy or using a photo of yours yet selling another in reality. However one person making a 6:3:1 design can't preclude others from following this format.

 

Is this your design?

 

Moving onto the 6:2:1 manifolds there are more possibilities as to which pipes go where however, the classic "Bunch of bananas" manifold has been found on many of the successful TR Race cars

as well as the more basic which would seem to be a tubular version of the cast original so to speak

[Red 6]

Alec, beautifully sumarised.

 

I would like to add a few points to the debate.

 

Talk on exhaust manifolds for our cars always makes me chuckle. Everyone has an opinion often based on how well they get on with their manifold supplier (usually Phoenix) or what their mate who "does a lot of TR's" has told them.

 

If you have been around for a bit you will be wise to the "knowlegeable experts" who baffle their audience with b******!

 

Our 6 cylinder engines are of an old design, they were put into cars which met the consumers needs of the time and which were made using the available technology to enable the cheapest finished unit cost.

 

I hate to say it our cars are as a pigs ear to a "formula 1 car" and no amount of "design expertise and experience" however gained will turn them into silk purses, there will be no water into wine experiences from any contributor on this thread.

 

We all know that to make our cars quicker, better flow in and out of the cylinderhead and frankly any of the aftermarket manifolds will do this whoever designed it.

 

I have experienced the pen ultimate £12k engine, yes it had titanium in it, and "steel" (more laughs) and when i rebuilt it it worked better than when i got it, but that dosnt make me an engine Guru.

 

So to my point, i am sick and tired of listening to and reading opinions from "experts" who know how to do everything better than everyone else. If these people are experts then why are they wasting their time on a 50 year old engine design on which everything is known and done but 40 years earlier!

 

Get a life!, or better still get the book tuning 4 stroke engines for performance by A Graham Bell. There you will find all the source material used by our experts but from the pen of a professor, so he does know what he is talking about!

[Red 6]

Has he gone yet?

[Andy Moltu]

My other hat is recording engineer...which has a huge relevance to acoustics and exhaust design.

I've had the fortune to work with some pretty famous people, and at the end you have to take a clear decision how to do things.

 

I can say I have the luck to be able to come up with the "THE BOTTOM LINE IS" thingy, and be able to take a clear decision..

This may have to be defended sometimes, by nothing more than the "feeling in the nose", or that rarifying thing called "common sense", until you yourself get a grasp on why it is, what you did works....

 

However in terms of approach....

If I didn't keep my options open, and lots of imagination, I would never get anything at all there either.....

 

I tend to work over the years with a lot of uncompromising and creative individuals too, and it invariably ends up with there being ONLY ONE RIGHT WAY to get the results.

Working with uncompromising people rubs off, and you too, become less willing to be diplomatic and tactful....it's normal.

 

I've seen SO MUCH of this kind of thing in engineering, and I'm unlikely to change my approach tomorrow..like it or not.

Fame and ability like subjectivity & objectivity are two different things and all too easily confused in our fame obsessed society.

 

I can say I have the luck to be able to come up with the "THE BOTTOM LINE IS" thingy, and be able to take a clear decision..

I tend to work over the years with a lot of uncompromising and creative individuals too, and it invariably ends up with there being ONLY ONE RIGHT WAY to get the results.

 

History and evolution are littered with examples of those who were certain that there way was the right & only way until they reach a dead end or someone does it better.

Edited July 31, 2007 by andymoltu

[JRCWeedon]

Has he gone yet?

Let us hope so

Regards

John

[JohnC]

It's really quite amusing reading responses to posts which may be there but which I can't see 'cos I'm playing with the "Ignore" option in my forum Control Panel

Cheers,

John

[tr250team]

hy,

thanks for your interest...

for GT (garett thomas) he made the same shambles in the "amicale spitfire " forum and he finished to be expel of the forum (if i catch him i will make him a head with "big valves")

i think i will buy a 6-3-1 manifiold with a single line race exhaust...

[dblenk]

hy,

thanks for your interest...

for GT (garett thomas) he made the same shambles in the "amicale spitfire " forum and he finished to be expel of the forum (if i catch him i will make him a head with "big valves")

i think i will buy a 6-3-1 manifiold with a single line race exhaust...

 

Pleased you got sorted , i got confused aswell

i have had a chat with pheonix about their bits and they do a std looking silencer but with modified internals and a big bore going in so it looks std but big bore with the manifold

 

regards

 

david

[rpurchon]

gt ee i have a question for gtee i have just fitted phoenix 631 manifold, i can see the primary pipes on no1 and 6 are longer than the others.& the bends are fabricated. i couldnt or wouldnt be able to pay more for a manifold, i am on a budget.[i could buy a usable car for that price]

how poorer a design is the phoenix to your original in your opinion. 10% less 25%less.??

richard

[rpurchon]

I just got sent a dyno report today.

 

Evidence of flat spots quite strong between 3400-4000rpm, and it hits a brick wall at 5800.

Power does not build well until about 3000, staying pretty flat and lacklustre below 2500.

It's better than the original one, and any of the 6-2-1 thingies invented by SAH etc etc.

You get what you pay for.

 

Is that concise and to the point?

 

how about tuning for torque.140 bhp at 5000+rev is no good in my opinion

i would rather have bottom end grunt. 3500 revs =85 mph.i wont be going racing.

and i dont pretend im driving a racing car.or cant you have one without the other.

richard

[rpurchon]

no worries, you will get a solid enough 165-170 on that car at 5000-5500 with no modifications whatsoever to a CP engine.

 

Torque at 3000 is at least 20% higher than before.

 

Only the metering unit needs to be changed.

 

There are other people here who have done it and are happy.

 

i have SUs with cr cam plus a few other bits. richard

[rpurchon]

In which case you could fit the original cast iron manifold with practically no change in power and maybe more torque low down.

 

The 6-3 design benefits most from using hotter cams. That's why it was made.

 

i had a rusting 6-2 mild steel one. oh well at least it wont rust away.

when my car turns into a pile of red dust, i can sell it on ebay?

richard

[stephen cooper]

.

Edited April 2, 2011 by stephen cooper

[marvmul]

Get rid of the 6-2. A CP engine + GT's 6-3-1 and MU + his tip on the inlet tract = TORQUE

GT's 6-3-1 : rpurchon will have to have it made by someone else? I wonder where anything of GT's parts can be ordered or bought?

Besides, no exhaust system is perfect on it's own or can simply be bold on. Even GT can't tell what dimensions of his 30+bhp exhaust system will fit rpurchons engine.

Edited August 4, 2007 by marvmul

[Guest ron]

Just because you live in Belgium, the historic capital of textiles, does it entitle you to make "blanket" criticisms about everything I do?

 

I just don't think you know what you are talking about quite frankly......

 

GTee

Marvmul has been on this forum a long while and has contributed a lot of knowledgeable and useful info to a lot of people, whereas you have added nothing but a load of BS, most of which has been gleened either from Google or from the book 'How to Bluff your way on a Classic Car Forum' do us all a favour and go forth and multiply.

Regards,

Ron

[rpurchon]

Just because you live in Belgium, the historic capital of textiles, does it entitle you to make "blanket" criticisms about everything I do?

 

I just don't think you know what you are talking about quite frankly......

 

 

 

i was thinking more on the lines of cam shafts.i have my early cc camshaft 10/50 which did pull from 1000 revs .

cc torque figures arent much below a cp car. unless theyre a load of triumph pie in the sky.

new engine and cr camshaft 18/58 doesnt pull as well bottom end 2000 revs. i cant really say it goes much better top end.

it dont rev it past 5000. dont get me wrong it will go,its quicker than a friends mr2 up to 90mph.above that its pointless anyway.

iv yet to meet another tr6 at the lights to compare it with. it does 30 mpg so i dont want to swap the SUs

so any thoughts on cam shafts, setting a few deg early?

richard

[stephen cooper]

Hi rpurchon, You'd definately benefit from a cam swap! Speaking from experience here as my GT6 engine has the 10/50 cam fitted - great from tickover as you say but not for much else,- big difference compared to the CP engine fitted with PI.

 

You'll need a hotter cam to get the best from a 6-3-1. If your keeping the SUs I'd go for TR5/early 6 spec cam, 6-3-1 with the SUs on the s type manifold and K&Ns or trumpets and richer needles of course, dizzy will need attention and you'll probably also need to bring the CR up if its a US engine?

 

Marvmul, you can buy GT's parts. I believe some goodies are coming out quite soon.

 

Cheers Steve

[rpurchon]

Hi rpurchon, You'd definately benefit from a cam swap! Speaking from experience here as my GT6 engine has the 10/50 cam fitted - great from tickover as you say but not for much else,- big difference compared to the CP engine fitted with PI.

 

You'll need a hotter cam to get the best from a 6-3-1. If your keeping the SUs I'd go for TR5/early 6 spec cam, 6-3-1 with the SUs on the s type manifold and K&Ns or trumpets and richer needles of course, dizzy will need attention and you'll probably also need to bring the CR up if its a US engine?

 

Marvmul, you can buy GT's parts. I believe some goodies are coming out quite soon.

 

Cheers Steve

 

yes i have done all those.big k n air filter on front 4" pipe to a big airbox. late 2.5 s head, electric fan ditched the cast iron blob that the fan sits on .light flywheel. needle thrusts in the gbox. might try cp cam.i dont want to go pi,

if it was that good all 5&6 would be running on them, theyre must have been enogh 2.5 scrapped to convert every one.

but then again ive never driven one.

i think i am at the limits of what i can get.

richard

[rpurchon]

In life you can't have everything.

You can't have a top model blonde sex bomb as a wife and expect her to be faithful or not divorce you when she find a better man/more money/bigger house/larger garden.... (add in this space as you like)....

 

You can't have the accuracy of an atomic clock from an old Omega wind-up...

 

If you REALLY want Torque from 1500rpm and power to 5000+, then you have to get a car with a 4 valve DOHC engine, and a long stroke all steel bottom end of at least 4.0L, with a proper modern design of head and decent valve area.....

I can think of a few, but the one that springs closest to mind from Coventry was the AJ16 which finished production about 10 years ago, and that resembled the Jaguar XJ6 4.2L museum engine quite a bit which preceded it..

 

That is to say if you INSIST on choking DOWN the engine and detuning it (like a Citrouen CX), then you can't get it to rev too...

 

So the only substitute is doubling its size and making it INLINE not V

 

well ive never driven one with pi or webers so i dont know. so i guess its dump the SUs or be content with what i have got. richard

[rpurchon]

I don't think anyone who has ever owned a 2.5S would agree about "pulling like a train".

I've owned quite a few, (and I still have a rare estate one btw)

They are DREADFUL lacklustre units typical of the last (evil) days in Coventry producing bad cars that rot like mad...

 

I don't think you will find a single person knowing about those old saloons that would reccomend you to fit what is basically a boring old US spec engine to that car, complete with it's massive overweight flywheel, struggling to make 100bhp, when you could easily fit an early Pi saloon engine and run it on carbs.....

 

You can find a good s/h early 2.5Pi engine for probably about 100£ if you look hard.

With that Spitfire M11 cam they used...they go really well particularly on SUs, and will benefit from using either the original TR6 cast manifold OR the 6-3-1 design......in which case you may be able to wind it up to about 140bhp, -

but you will have to fit an anti run-on valve, for when you switch it off.

 

 

this might be of interst to others scroll down for camshfts. youve even got a mention g thomas.

[john.r.davies]

this might be of interst to others scroll down for camshfts. youve even got a mention g thomas.

 

Or even: http://www.kvaleberg.com/t_tune.html where you can see the original page without losing the pics and graphs.

John