My manifold is cracked……Cast or Stainless replacement?

[dodge1979]

What are the dyno testing results of the manifold? How many agressive runs on the dyno has it made? The inclusion of gaskets and studs shouldnt really be a selling point on this item surely?

[sailorbob]

The selling points are that it's made of a good grade of stainless steel (many are lesser grades, use mild steel flanges etc), manufactured by a firm with a good reputation who are willing to offer a warranty, been used on a car that gets some hard use (track days) and had no nasty sharp bends or joining transitions.

Edited October 30, 2012 by sailorbob

[dodge1979]

Well thats all part of designing a manifold to do a.job well, but are there any dyno results showing how it.improves the flow characteristics of.the engine, its possible power and torque differences to standard, how it affects the turbos.spooling, and not just top end figures...how.throughout the rev range it.affects the dynamics.of.the engine whether they be good or bad? Thats the information that needs to be shown so people who want to change manifolds, like myself not for having a faulty cast one but because I want a more efficient system, can compare between whats available. Whilst I wouldnt doubt it could make improvements, the quality, extent and. Practical use of such improvements needs to be clarified with reliable comparison data...

[sailorbob]

I've never seen a back to back comparison of manifolds for the Esprit. Kind of makes it hard to say whether one manifold is better (or worse) than another.

[dodge1979]

True, but if someone is selling a desing then surely they have done dyno runs and development, using the same engine, to show pre manifold, ie on the original setup, and then runs using their design..as it is developed up to the final unit. Which would show the complete data...the point I was asking is have they this data to show? It doesnt matter at the moment about comparing it to other manifolds, until data is available for another unit...which im sure shortly it will. So, does this company have this data to share does anyone know?

[sailorbob]

As I said previously, I've never seen a back to back comparison for Esprit manifolds. I cannot comment on whether this particular manifold has that done but I suspect not (hopefully Mark can confirm either way). In this regard, it's probably no different to any other fabricated manifold.

BTW, I wasn't talking about comparing this manifold to other fabricated manifolds, I referring to the OE cast manifold which is what most (if not all) people would be replacing.

[dodge1979]

Ah sorry derek misread there...thought you meant against other replacements..even so that would make interesting viewing as on previous threads its been found manufacturers claims to be somewhat hopefull and unfounded in certain things...but I digress. Well as a manifold manufacturer it would only be logical to have done such a basic comparison on their product vs standard otherwise any claims could be unsubstantiated...in my opinion of course. Yes if mark can shed any light?

On another note, the revised version mentioned earlier in the thread... Is that the 'sectional' version I think ive read about..cant rekember where now...that is assemble on the car in a few sections with clamps joining them up? If I remember right this was to get over tye clearance and assembly in situ issues with the first design..if so this would allow more room for failure nd leaks surely? Also mentioned somewhere above is the use. Of composite gaskets and something about silicon sealer? Without reading back I cant remember quite the reference..but if so surely this is a 'solution' to poor mating faces or flange design/finish...questions not aimed at you derek just generally at the masses!

[sailorbob]

I doubt whether any fabricated manifold manufacturer has done any dyno testing as there's such a small market for these bespoke items. It would be down to a rather keen owner to find this out.

The Alunox manifold isn't sectional but if it were, and the joints were done properly, it would bother me. An accurately formed double slip joint will leak very little exhaust gas when cold and quickly become gas tight shortly after start up. The biggest issue I see with the Esprit manifold is the great weight of the turbo and cat hanging off to the rear of the engine and acting as a big lever.

[dodge1979]

I must be thinking of a different manifold then regarding the.joints...but I would find it.odd if no data is available..but we shall wait.to see what can be found I guess..

[mdw]

I must be thinking of a different manifold then regarding the.joints...but I would find it.odd if no data is available..but we shall wait.to see what can be found I guess..

Thats Sjs with a joint on each pipe

[andydclements]

Also Mike Taylor's NA systems have slip joints and springs on each pipe.

[dodge1979]

Yes, but obviously the n/a system isnt subject to quite the issues of the turbo system....ive also seen mikes (lotusbits) dyno testing data last year. He again uses Northampton Motorsports to develop his rally car/product on, a well established and proven company.

[MarkKassim]

Hi Derek. I’ve been looking at your comments, I will try and answer them as best I can.

The 1^st point is this manifold isn’t just a like for like replacement for the original cast one in terms of the material it’s made of and the equal tuned lengths of the pipes.

It’s made of stainless 321 which are used in high end race car applications such as the Indy cars with their enclosed engine compartments and thermal clam-shell enclosures around their turbocharger headers. They must thermally wrap their exhaust pipes just so the radiant heat off the tubes won't cause fires or melt any critical systems. In this case headers made out of mild steel OR 304 STAINLESS STEEL would completely fail and break apart due to the severe heat retention, let alone scale and send death particles into the turbocharger, ruining the turbine blades. 321 stainless steel has excellent high temperature fatigue resistance in this enclosed application and does a dam good job of living in this hostile environment better than any other material except the ultra-high nickel content steels ( such an Inconel ), which are hard to find, very difficult to work with and extremely expensive.

Within the 300 series of stainless steels, there are four types that are suitable, available and cost effective for the racer. These are 304, 316L, 321, and 347

321 and 347 are known as stabilised grades of stainless. These are alloyed with either titanium (321) or columbium (347), both of which have a much stronger affinity for carbon than does chromium at elevated temperatures.

304 is the most inexpensive and available stainless in the 300 series. It is suitable for normally-aspirated header applications, and has been successfully used by many racing teams. It does not have the high temperature fatigue resistance that 321 does, but is considerably less costly and much more available.

304 IS NOT USED IN TURBO MANIFOLDS APPLICATION BECAUSE IT WILL FAIL UNDER AGGRESSIVE USE. THIS TAKES ABOUT 1 TO 2 YEARS TO HAPPEN IN NORMAL USE,BUT IN RACE CONDITIONS ALUNOX HAVE EVEN SEEN THEM FALL APART WITH IN A FEW HOURS.

THIS IS WHAT WILL HAPPEN IF A TURBO SYSTEM IS MADE IN VERY FINE 304 ,CRAKES WILL START TO APPEAR ON WELDED JOINTS THESE CRAKES WILL THEN SPLINTER AND BRAKE OFF CAUSING TURBO FAILURE

Going back to the design of the manifold, cylinders 1 and 4 collect together and 2 and 3 ,but this time running equal lengths in a 4 into 2 into 1 configuration, meaning the gases will arrive at the turbo in a more synchronised manner. You will also notice the header design optimised for gas flow

This can be heard in the exhaust note. The stainless steel also provides better gas flow in the manifold unlike the rough service of the cast one, which also degrades and flack's into the exhaust.

The point about the testing , well it hasn’t been tested on a dyno ,like you say for such small numbers this would be expensive, but I’m willing to put it on one if the opportunity arises. If I was asked to give an estimation from the driving experience I would say a 15 – 20 BHP increase, trying not to confuse power the better throttle response.

It has made a very noticeable difference in the overall driveability of the car, in terms of better high end performance i.e. revving harder for longer and also it seems to reduce turbo lag giving better throttle response probably most noticeable at low revs. You seem to able to change gear earlier and still pick speed giving a more rewarding driving experience even without driving it hard.

I have done a number of Track days with the manifold, taking the car out about every 0.5 hour and driving for about 20 – 25 minutes at a time. Pushing it as hard as I can, I’m talking 7/ 8000 rpm in each gear braking as hard as I can and as late as I can for each corner.

This has put the manifold through may heat/cool cycles and applied as may forces as possible, which to be honest you’re not going to do on the road. I been running it over a year now and it has been back to Alunox for inspection just to give a health check and there are no signs of cracks , sagging or any other imperfections.

You mentioned Slip Joints , Alunox make most of their systems with these and are currently producing a variation of this manifold with Slip Joints which will be good for over 400 BHP up 700BHP . Pictures to follow soon.

I have PNMs uprated brakes front 310mm / Rears 300mm 4 pots, which also held up well. I did rebuild the engine completely about 6 years ago, but I do have to say I’m amazed how the rest of car has been holding up.

The manifold seems to have enhanced all my other modifications such as the red race code 6 chip ,CAT Bypass and green cotton air filter.

Going back to the price and group buy. Like you said this is a very high end piece of kit made by a company who supply F1 racing teams and whose reputation depends on durability and design to give the edge on the track. And so are willing to give a warranty on the manifold. The price includes all studs / Nuts and gaskets.

The group buy for 10 is £850

If we can get a group buy of 30 the price would come down to £715 with free UK postage and for international customers about £50 . USA postage is between £50 and £70

[dodge1979]

So then its not a.tested and tuned item with proper data to show.exactly what effect it has on the engine dynamics...whilst I wouldnt doubt the manufacturers experience with other applications...i would have a few questions though, especially if I was parting with the best part or a grand...which is.what those interested in doing are looking at.

How do the gasses arive at the turbo in a more.synchronized manner? How is this known to happen and in what manner is it happening...

In what way has the header been optimized.for.gas flow? How.again can this be shown? Because the exhaust sounds like it is, im afraid, well..

In terms of potential.power increases, these can only be shown with dyno testings before and after fitment. Torque would be more 'feelable' by driving..

The driving differences you describe, are what were all looking for...so I wouldnt doubt that improvements are made..obviously the point is how and to what level etc...

The slipper joint manifold I mentioned would certainly not be my first choice for a turbo application like the esprit With its unique demands....

Id very much like to know also how on earth this manifold is good for 400 to 700bhp...based upon what data? What tests? Or is it a case or 'oh its built to that'... Which ive heard somewhere before on another unsubstantiated product... To develope something for the Esprit turbo, based upon say a 700bhp cosworth engine design, and say yeah it works on that itll be good for this...would be laughable (not that im saying thats the case, just an example).... So without proper develpment data, its a figure plucked out of the air I guess.

The only reason im being picky, is because like others, if im parting with a chunk of hard earned cash I want to make sure its on the best product available...proven. No matter where it comes from. Thats all..

[sailorbob]

Mark, many thanks for the extra information.

Darren, a double slip joint is exactly the kind of feature you need to deal with expansion issues. BTW, I haven't seen any of the information you're looking for on any of the fabricated manifolds.

Edited October 31, 2012 by sailorbob

[dodge1979]

IDepends on the design I guess..and no your right, other ones havent.except for daves unit. Which, in honesty is the only other one worth looking at. That has been massively developed on the dyno with real results, which hqve been shown in depth on the forum here in the 412 thread...and thats why im keen to see the data for this one too as it appears to have a good review by mark..but the hard data is the decider.

Now whichever I go for, iwill put on the dyno at Northampton. Ive used this established dyno to show the realistic results of the commonly performed upgrades most of us do to the Esprit inanother thread, and as such ill be able to provide before and after results...but obviously that wont be just yet..so when this happens, im sure itl.provide more interesting debate..

[sailorbob]

There is some information on Dave's manifold but the trouble is that this has all been done in conjunction with lots of other engine modifications Whilst it's come together as excellent example of what can be achieved with the engine this, IMHO, cannot be taken as a guide to the performance of a single part of that build. I think we are on the same page when it comes to wanting to know what gains there may be had but there isn't the back to back data on the OE manifold vs a fabricated manifold to substantiate what these may be.

[dodge1979]

Indeed we are! I cant remember where abouts in the thread, or.indeed it might have been in a private conversation, a discussion regarding the flow dynamics and pulse tuning of the manifold during its development. Its in this area that the true gains were designed, calculated, constructed and tested aggressively, which in turn allowed the development and benefits of other modifications to work. But dont also forget, dave .is.running a standard engine..as you and I are...its.been meticulously built exacting per factory specifications, but is.still the same engine using the same components as all of.ours..the other modifications were to see how far that engine could go....and the key unit to any mods is.getting air in and as importantly getting the gases out....but getting them out in such a way that they are then used to good.effect as they travel..ie, pulse tuning to allow each cycle to exit without disruption to the next exiting gas cycle...controlling the speeds at which gases are drawn out of.the combustion chamber to gain further effects and benefits.. This sort.of thing. Combined and developed in tune with the engines 'cam overlap' to prevent exhaust gases being drawn back into the.combustion chamber, contaminating the fresh charge...and potentially blowing back into the inlet track in minute amounts...any disruption in flow through the manifold will result in turbo spooling issues and whilst the average driver may not see this, it is apprant on a dyno, or, the gains by designing correctly are apparent... Where the headers meet, for example is a classic area of disruption too..if two branches of gases collide without having been tuned amd controlled they will have negative effects..but the oposite is possible with correct design and application.. This is just one area of the development of that manifold which goes beyond other ones available, with data available to show its use and potentials...whereas there, so far, isnt anything that can support the claims of the allunox unit...

Edited November 1, 2012 by dodge1979

[MarkKassim]

When I say good for over 400 BHP up 700BHP, I do mean that the slip joint design can with stand that sort of power , not that it will make your Esprit produce it. Sorry for any confusion.

[dodge1979]

Oh I know the.esprit wont produce those figures without serious development on all areas, and even then it wouldnt be anywhere up to 700bhp....but a slipper joint design might be capable of high power in a n/a,but the manifold wont in this application! But that digresses though..but on another note, if a slipper joint is clamped up correct and gas tight, surelt it will act as a solid unit when assembled...and what I think is the important factor in a manifold for the esprit, is.that a.design may work on.other.turbo applications but its the extreme heat unique on our units that cause.the issues.

[sailorbob]

A double slip joint isn't bolted together otherwise there would be no ability for the separate parts to 'slip' and allow for expansion and contraction. You may see springs used on some manifold / exhaust systems.

[gixxer]

Nothing like a slip joint and it's air leaks, in conjunction with an O2 sensor.

[dodge1979]

Sorry clamped wasnt the right wording...i was in a rush to get off the loo (we all do our thinking there!) but still, when fully assembled and held together as one complete unit by whichever means, is what should have been there...anyhow, as the joints are moving, contracting, eexpanding etc there is a.risk of leakage. There has to be, no matter how minute..otherwise they wouldnt 'move' as designed..which is why I would be against that in a turbo setup with such extreme heat as per ours..any fluctuation will affect tuning and performance, you may not.notice this driving but (back to the dyno I know, sorry) it would be.visable on a dyno mapping.also, what are the long term effects on this type of joint in a turbo,high temperature aggressive environment..the slippers, the springs, their mounting points and tension etc...if anything that flexes,moves or expands/contracts is susceptible to failure in one manner or another, then is the risk not higher with multiple uses of these items on one application...if one tiny fault occurs, does this put the strain on the other items, pushing them beyond their individual function and as a whole, the unit is then not performing as it should...the same can be said of a.welded or cast manifold...but as that is.designed as one unit, not several assemblies, its chances are much less.. IF its design and build is correct.

Edited November 2, 2012 by dodge1979

[AlanDavies]

Hi Derek ,I've spoke with the guy from Alunox and he offering the warrantee,so I'm with you. Count me in At £850. Mark put me down.

Thanks Alan.

[MarkKassim]

Going back to the slip joint design , its the same layout as mine but with the slip joint in the collector allowing for greater movement ,this is extra protection for cars with very high power outputs. When fitting you can now attatch a branch at a time allowing better access to bolts , then fit the down pipes last . A few have been sold , would be good to get feed back on here.

Alan ,thanks I will put you down , but we will need more interest to get that price. Mark

Edited November 27, 2012 by MarkKassim