Porsche Enthusiasts Club Forum

Wes, thanks for the added info. As for the manifold my guy can build any kind of manifold you want. In fact I was only talking to him about yours and johns supercharged car on Saturday whilst looking at his turbo and supercharged Napier Railton replica he's in mid build from scratch. The pipework on that thing is a work of art. He makes manifolds for offshore powerboats and has worked on all kinds of historic and classic race cars. In fact he can make or modify just about anything made from metals or alloys. I did say I wanted to take a picture of his car and send it to you guys. I'll try next time I'm there and email it.

Also added another piece of future engine security today with a Phormula KS-4 knock detector. Christmas is certainly coming early for my car this year!

I was mildly surprised by the Zircotec Primary coating quotes today. No brainier in getting the j pipe and front section done even though its not as high performing as the other coatings it is far better than nothing. Also protects from corrosion and makes the parts look as good as new again. Shame the wastegate will be letting the side down but that's on my list for the distant future.

Your guy sounds interesting indeed! It's so much easier to get someone to make one but spendy. If and when I get my car back up and running I'm going to look at repositioning the turbo, probably right up at the front.

Having said that though, if the cast manifold behaves itself and the car runs strong, then why mess with it?

There's a good exhaust place near me. I do fancy a full 3-4" system (who needs silencers?). A friend of mine has an insanely modified Audi S4 Biturbo. They made a full twin system for that and it sounds awesome (V6 does help). That car is so quick you can't change gear quick enough. 8 pot calipers on the front of it!!

Nice one with the Phormula KS-4, they look really good. You can output to a standalone ECU from it for knock control. It may turn out to be the best thing you've invested in.

Bugger! Both the #4 and #6 housings are badly cracked plus new shafts are required. Shafts were no surprise but having now to source a new #6 housing in usable condition isn't going to be easy I guess. A new housing I suspect will be spendy!!

Damn, blast and *!~#!!!

New K26 turbine housings with 3 bolt flanges for 924 turbo are NLA. This is going to be an issue with all S1 and S2 versions of cars as regardless of driving style as these will eventually crack through and are non weldable, if you do they will fail again.

If no used options are available then we will all need to find a modern alternative to the K26 3 bolt housing/manifold to keep our cars on the road.

So anyone with an S1 K26 #6 3 bolt flange turbine housing which has no cracks?? The cracks are not necessarily visible without proper crack testing.

My cracked 6 housing pic below. Replacement needed asap, anyone got a spare S1 turbo turbine housing or complete turbo on the shelf?



On the plus side I have some more freshly Zircotec'd ceramic coated exhaust parts

Front pipe which I modified last year to remove the mid silencer and install a stainless replacement section. AFR bung installed at the same time


S2 J pipe


Also picked up a Phormula KS-4 knock detector to help keep this engine in check. Engine is still mid build. Car is still in the paint shop having a fresh coat of paint in the engine bay and some blemishes repainted on the roof. Lots of parts have refurbed, repainted or replaced with new. Itching to get all my bits back together soon!!

Santa arrived early in my house today. It should have gone under the tree ready for the 25th, but I couldn't help myself!!

So here we have is a K26 2660 6.10 which is 924 Carrera GT spec. All fresh as a daisy with Zircotec Performance Metallic Black ceramic coating to match the previously done manifold and will work well with the Primary Black ceramic coated exhaust front pipe and J pipe.





I really want my car and rebuilt engine back right now!!

Oh wow pass me the Kleenex!! That looks fantastic - good ole Santa! I've seen those ceramic coatings in different colours advertised, it's a very nice finish. I guess it will last very well too?

B.E.A.Utiful!!! That is a good looking turbo.

I dip in and out of this thread but I love catching up with it

Below is a pic of a S2 turbo taken last Summer in Switzerland I have just found ont'interweb. I'd like to know more about it. Spec, power, wheres all the vacuum hoses ended up, what happened to the vacuum limiter and AAV valve, how's the IC set up etc. etc.

Interesting that its moved the intake/TB to the end of the plenum as I am in the middle of doing

Can't answer any of your questions - but looks nice! Plus I've heard the old use of stockings/tights for a temporary repair to a broken fan belt but looks like they've covered the air filter with similar!

Thread resurrection time

Just read the Nicksonmotorsport Carrera GT thread and Jon said:-

"Engine wise, the CGT, CGTS and the standard 924 turbo can be fragile if modified, but with some better pistons and tuning 400 BHP can be seen without too much complication, I am sure 600 BHP could also be seen with a decent budget."

This got me thinking, what would it take for 600hp? So I fed some quick numbers into the Borg Warner Matchbot utility for sizing their EFR range of turbos. Although it may not have the nth degree of accuracy, it's still a good tool.
This is what I came up with on their twin scroll 8374 EFR turbo - this would obviously be mated to a proper split-pulse manifold to make use of the twin scroll turbine housing:-
http://www.turbodriven.com//performanceturbos/matchbot/index.html#version=1.2&displacement=2.03&CID=123.8706&altitude=500&baro=14.502&aat=70&turboconfig=1&compressor=83s75&pt1_rpm=3000&pt1_ve=85&pt1_boost=4&pt1_ie=90&pt1_filres=0.4&pt1_ipd=0.2&pt1_mbp=0.5&pt1_ce=60&pt1_te=90&pt1_egt=1600&pt1_ter=1.16&pt1_pw=19.48&pt1_bsfc=0.42&pt1_afr=12&pt1_wts=162&pt1_wd=62&pt1_wd2=74&pt1_wrsin=69033&pt2_rpm=4000&pt2_ve=90&pt2_boost=9&pt2_ie=90&pt2_filres=0.4&pt2_ipd=0.5&pt2_mbp=0.8&pt2_ce=64&pt2_te=83&pt2_egt=1700&pt2_ter=1.32&pt2_pw=13.08&pt2_bsfc=0.5&pt2_afr=12&pt2_wts=314&pt2_wd=62&pt2_wd2=74&pt2_wrsin=73635&pt3_rpm=5000&pt3_ve=100&pt3_boost=27&pt3_ie=80&pt3_filres=0.5&pt3_ipd=1&pt3_mbp=1&pt3_ce=69&pt3_te=72&pt3_egt=1700&pt3_ter=2.07&pt3_pw=13.13&pt3_bsfc=0.55&pt3_afr=11.5&pt3_wts=450&pt3_wd=62&pt3_wd2=74&pt3_wrsin=78238&pt4_rpm=6000&pt4_ve=100&pt4_boost=38&pt4_ie=80&pt4_filres=0.5&pt4_ipd=1&pt4_mbp=1.2&pt4_ce=73&pt4_te=71&pt4_egt=1750&pt4_ter=2.69&pt4_pw=22.49&pt4_bsfc=0.55&pt4_afr=11.5&pt4_wts=450&pt4_wd=62&pt4_wd2=74&pt4_wrsin=84681&pt5_rpm=7000&pt5_ve=95&pt5_boost=38&pt5_ie=80&pt5_filres=0.5&pt5_ipd=1&pt5_mbp=1.4&pt5_ce=73&pt5_te=70&pt5_egt=1750&pt5_ter=2.84&pt5_pw=24.97&pt5_bsfc=0.55&pt5_afr=11.5&pt5_wts=475&pt5_wd=62&pt5_wd2=74&pt5_wrsin=92044&pt6_rpm=8000&pt6_ve=95&pt6_boost=38&pt6_ie=80&pt6_filres=0.5&pt6_ipd=1&pt6_mbp=1.6&pt6_ce=72&pt6_te=70&pt6_egt=1750&pt6_ter=3.06&pt6_pw=28.36&pt6_bsfc=0.55&pt6_afr=11.5&pt6_wts=505&pt6_wd=62&pt6_wd2=74&pt6_wrsin=92044&

So, 613.5hp @8000rpm with 38psi max boost.

I've seen Evos and such running 40psi+ but what does it take to avoid detonation at those boost levels apart from super-efficient compressor and inter cooling when you only have 98/99RON fuel (if you're lucky)?

What's the max static CR you could run at such levels of boost and would additional water/alcohol injection be needed?

Honda ran 2.5bar boost pressure on their 9.4:1CR F1 engine but that had pent-roof chambers and 102RON with Toluene - here is a nice link to their technical PDF for the same engine:-

http://www.k20a.org/upload/HondaRA168EEngine.pdf

We have better turbos and better management possibilities now, so I wonder what is achievable with the 'van' engine

The MatchBot is a cool tool indeed

By "a decent budget" I would be talking about a steel lightweight crank, dry sump, forged con rods, forged pistons, non CIS injection and some serious electronics to keep detonation in check. Not only this, but the car would be running a different configuration on the turbo location, exhaust routing etc.

With the Matchbot, using your same figures,

bring the AFR down to 10 to 1, as at that kind of boost level you will require this kind of mixture to cool the valves, partially to cool the intake charge and also to give the best power from each stroke,

the ambient air temperature to UK average summer temperature of 60 degrees F (so as long as it is not a hotter than average summer day, it could be used at full boost.) and up the RPM to 9000 rpm, which is a non too crazy rpm if your lucky for a wet sump engine, but for a 924T or CGT you would ideally want a dry sump above 7000 rpm to stop the pump cavitation and foaming.

At that point, you should be seeing 611 BHP at 9000 rpm with just 24 psi of boost.

In the real world though , I would expect to have to run a higher boost level to achieve 600 bhp on a 924 engine, probably about 30 psi

We have run 944 turbo's at 24 psi of boost, even with the 944 turbo's delicate unsupported bore, which is the main thing with the 924 turbo, which could see it surviving very high boost pressures is that it has a cast iron block and "bores that can't walk" which may seem like an odd claim, but can hold 944 turbos back with standard bore configurations.

30 psi or higher is not a problem for iron block engines

To sustain 9000 rpm, we would be looking at an all steel crank £2500, h-section or I-beam forged con rods £1000, a good custom dry sump setup £2500 and a full engine build with forged pistons with several key modifications. Not to mention EFI, knock detection and knock elimination hardware.

Water injection, fuel cooling and other modifications could be used if the BHP fell short of 600, or could be used to take the power beyond 600 bhp.

I would be tempted to think of twin stage turbo's, which could be used to bring on the boost much earlier, because a turbo with that much capacity would usually not come on boost until quite late, but a twin stage system should be able to allow boost to come on even lower than standard spool up. Quite an expensive option though.

But all of this is an expensive option, tripling the output of an engine always is. I would expect a budget of £15k to £20k on the engine and support hardware.

So here's the first time I've thrown the intake manifold, TB and intake duct together. Still work in progress in plumbing it all in and loosing superfluous items. I also put the TB back together wrongly!

Carrera GTS 310bhp engine rebuild and on track

http://www.youtube.com/watch?feature=pl ... TVYcsejP5c

Looking good Steve,

I like the re-using of the pre throttle body pipe, I take it will be coupling straight onto the FMIC? how much of a rubber/silicone section will you use to couple them together?