Are we missing something? Exhaust Manifold Thread II

[Barry911]

Is it me, or do we seem to be missing a certain cast-iron exhaust manifold thread. Apologies if I'm overlooking it.

 

Was it just too much goodwill, bonhomie and mutual back-slapping?

 

In which case, I'd like to repeat Trevor's question, that I'm pretty sure never did get answered:

 

With a stage two head, and a moderate cam, will the factory two outlet cast iron manifold be up to the job, or to put it another way, at what point does it become necessary to invest in a tubular manifold of some description?

 

Also, if going that route, what type of manifold, and what type of exhaust system?

 

Many thanks, and perhaps things can stay in the realms of the grown-ups this time ....

[RobinTR6]

You're correct, it was here this pm, now removed, and didn't get my answer either. Ho, hum , let's see what happens here.

[Alec Pringle]

Hi Barry,

 

moderators have a difficult job to do, and that job isn't made easier by the observations of some contributors.

 

Just occasionally a topic 'disappears' temporarily whilst it receives a touch of the blue pencil, or perhaps even requires perusal by a trained legal eyeball.

 

Generally speaking the topic is back in place soon enough, and we resume normal service.

 

It's a rare occurrence, to be fair, but very occasionally appropriate if someone is being intemperate and/or OTT.

 

Presumably something out of order has been posted today - or so I'd guess ?

 

Cheers

 

Alec

[Guest ntc]

The moderating team are doing there work,and good on them this is not facebook or twitter let it go.

Edited January 8, 2015 by ntc

[Barry911]

Ooh yes!

 

Well, genuine apologies to the mods if the thread was about to reappear: feel free to delete this one if appropriate.

 

Nevertheless, the original question was, and is valid, sensible and appropriate, and one way or another deserves answering fully in a sensible and rounded manner.

 

A good humoured and respectful exploration of the subject would make for an excellent reference piece in the future, as surely many people wanting to moderately tune their 6's must have pondered this.

[Barry911]

Sorry Neil, you beat me to it, I was replying to Alec.

[Guest ntc]

Ooh yes!

 

Well, genuine apologies to the mods if the thread was about to reappear: feel free to delete this one if appropriate.

 

Nevertheless, the original question was, and is valid, sensible and appropriate, and one way or another deserves answering fully in a sensible and rounded manner.

 

A good humoured and respectful exploration of the subject would make for an excellent reference piece in the future, as surely many people wanting to moderately tune their 6's must have pondered this.

Barry

A search on here will find the answers you require without the insults.

[GT6M]

Well when it comes back, heres my questionee,

 

Gareth, I just cannot seem to tek in how a Weber carb, wid its restrictions in the carb

ie,chokes, fuel pipe, venturi bit, which gives alott less air flow than a PI mani

can give moer power than a PI mani set up

 

PI only has a throttle plate restriction, carbs like webers have after throttle restrictions

 

i think ave cc area aboot 85 for PI and about 47 for webers, ruff calcs i know

but please say how less air intake, can mek moer power

 

I know that frae about 70% throttle, that there aint alott moer fuel needed {well mine anyway }

no matter what the revs, as engine just cant injest moer air

 

this is about par with most road,ish engines Ive seen dynoed when helping oot at my marra,s RR garage

 

could you elabourate on how a weber can flow moer air please.

 

M

Edited January 8, 2015 by GT6M

[Alec Pringle]

The Oxford dictionary offers an appropriate mantra for all amateur engine tuners - definition of faith.

 

" Strong belief in the doctrines of a religion, based on spiritual conviction rather than proof: "

 

Cheers

 

Alec

[Peter Cobbold]

Give faith a boost - fit a blower.

[snowric]

Which Kastner did also - so for once you seem to agree with him !

 

http://www.kaskastner.com/triumphworld_apr2004.pdf

 

That is an amazing extension which car did you put it in, I couldn't imagine those huge trumpets fitting my TR?

[GT6M]

Good reply Gareth, thanks

just thought all the restrictions in the carb would have made it worse.

live an learn.

 

M

[Peter Cobbold]

For anyone involved in visualising pressures resulting from air flows in machinery (at the walls) this pressure-sensitive fluorescent paint looks useful:

 

http://www.jameswgregory.com/psp.html

 

Its not obvious what pressures are detectable, but it reacts very fast.

 

Peter

[Barry911]

Good reply Gareth, thanks.

 

M

Ditto: very interesting, thank you.

[roy53]

To GTT

 

 

large increase in torque at 4500rpm with only a slight penality of the top end (7900-8500rpm)

 

 

 

Sorry to move of topic but as you mention these high revs,those of us that have engines that go beyond 7000 rpm are finding great trouble with the fan belt staying on and therefor losing the water pump.

Do you have any views on this being as you claim these high revs ? would be of great help.This is 6 cyl engines.

 

ROY

[Tom Fremont]

_{Re: the Webers - the standard inlet port diameter is 1.25" or 31.75mm. If using 32m chokes or larger where is the restriction? Throttle discs are either 40,42, or 45 mm so it ain't there. Indeed the valve looks like the culprit, which is borne out by all the measures taken to put it on a diet and lift it further out of the way, for longer time intervals .}

 

_{I've seen some TR6 engine recipes with 45 DCOEs and 36mm chokes ( I think they were 2.7l displacement though ).}

[Guest ntc]

There you go Roy time for him to come over here and see what a weber powered car can do.

[Alec Pringle]

Can we quantify the bottom line of any of this discussion in terms of race results ?

 

Cheers

 

Alec

[Alec Pringle]

I have this general conviction that I, along with the other contributors, am on the planet Earth . . . . that may of course be an illusion, a matter of faith rather than of scientific proof.

 

This current discussion was primarily concerned with TR6 exhaust manifolds, the questions raised by the original poster. The discussion is in the TR6 Technical Forum, a section of The TR Register Forum.

 

That suggests to me that the majority of readers might well be more concerned with 60s and 70s cars manufactured by Triumph than they are in the engines of proper single seaters let alone Ford Escorts - rightly or wrongly, the average TR enthusiast and owner does tend to take seriously "some old 60s car, where you can't open or shut the doors when you put one side on a trolley jack".

 

On that basis, I choose not to bore readers with too many accounts of the past years I spent managing proper single seater, sports or saloon car racing teams. All ancient history now, and the not inconsiderable number of exhaust systems commissioned from Mike Randall, and the various formula engines commissioned from John Reid, are of peripheral relevance at best, to the mild and minor tweaking of roadgoing TRs. Good chaps both, I concur, but sadly no longer with us.

 

There is an old saying to the effect that " when the flag drops, the bullship stops ", and nothing defines a successful competition engine like competition results. As Holbay found to their cost in their latter years.

 

However obsolete our cars might be, bearing in mind that the last efforts of the TR range in period were the best part of 35 years ago, we have nevertheless an honourable TRadition of TR sports cars and the TR Register being involved in classic and historic racing, rallying, hillclimbing and sprinting for more than 40 years, and spanning five decades. An involvement that, of course, is ongoing today and doubtless will be for many more years - just another aspect of preserving the marque TR, which is after all what this club is about . . . . .

 

Therefore I suggest that the competition results achieved by the various innovative tuning developments outlined would be of considerable interest to many readers.

 

So to more politely repeat my previous request " Can we please quantify the bottom line of any of this discussion in terms of competition results ? "

 

Cheers

 

Alec

Edited January 10, 2015 by Alec Pringle

[RogerH]

...that sounds like a fair request considering the original posters requirements.

 

Hi Gareth,

you have certainly displayed some very high level stuff and many of the posters are seriously interested in this.

 

Is there a bottom line from you for this thread.

 

Roger

[Peter Cobbold]

...that sounds like a fair request considering the original posters requirements.

 

Hi Gareth,

you have certainly displayed some very high level stuff and many of the posters are seriously interested in this.

 

Is there a bottom line from you for this thread.

 

Roger

Yes please Gareth. Can you repeat the losses you measured in the original exhaust silencer. And are there any data on the frictional losses meaured on a motored 2.5L engine ? Peter

[mike3739]

At this rate based on current posts, questions asked but none seem to be answered 2016

 

Cheers

 

Mike

[Peter Cobbold]

Gareth,

Many thanks, real measurements are valuable information. I kept twin pipes - bigger x-section area than single - but combined them alonside the diff iwth a 'Y' to feed a short single 3" bore straight-through silencer. Which ensures I cant go near a track day. So I plan to take a gentle 3"-bore bend from the Y into a cross box silencer.

 

 

Re. your sound engineering. I am currently wresting with 'Hartmann whistles', especially this paper where he can image 12kHz acoustic waves:

http://www.jameswgregory.com/papers/AIAA-2003-3713.pdf

Its quite new tech, must be useful somewhere in ic engines. My interest is using Hartmann tubes to atomise water to a fog. For octane !

 

Peter

Edited January 10, 2015 by Peter Cobbold

[Peter Cobbold]

At this rate based on current posts, questions asked but none seem to be answered 2016

 

Cheers

 

Mike

Maybe the radio silence is because its a far from simple question. Are there any before/after dyno measurements where nothing else in the exhaust/silencer or engine was changed apart from substituting the cast manifold? The forum is not short of earlier posts, but I haven't seem any numbers that answer the question.

 

Peter

 

 

even the 'Basics' are tricky:

http://www.epi-eng.com/piston_engine_technology/exhaust_system_technology.htm

[Peter Cobbold]

OT:-

Good luck with the anti-WT campaign.

We have a 20+ mega wind farm with the tallest masts/blades possible, only a mile or so from our village, and the noises drive me crazy.

.... all the more stupid because the country is completely self sufficient in oil shale and hydro!

 

I also checked the spectra from them. (mostly blade turbulence generated), what a mess!

 

It's not about NIMBY, it's about not being asked/consulted, then dumping a random industrial noise source where there wasn't one before.

If they did what was claimed - cut CO2 I would be less vocal against them. W/ts in Germany ( and probably Uk too, but they keep the info secret) operate at about 25% load factor but because of CO2 from back-up plant that has to be kept running when the wind blows they only displace carbon by about 7% of their rated power.

We get noise from just one 1.6MW machine mostly hidden form us by a hillside 900m away. When the wind blows from the wt to use we hear it, even indoors. Fortunately the wind is ot in that direction very much.

 

We lost the fight to erect 30 in the forest- permisison to build has been granted. But I has a small success - the owners can be taken to court for noise nuisance claims . Without my efforts dwellers in the forest would have had no protection from noise at all. And several are within 700m of two or three 2.5-5MW machines, and downwind most of the time. Ugh.

 

Peter