compression reduction, B234F + Turbo

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HenrikGM
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Re: compression reduction, B234F + Turbo

Inlägg av HenrikGM »

A small update.

The car has been dynoed on a rolling road to 561bhp/6073rpm, and 685Nm/5403rpm @295kpa manifold pressure. Ordinary Shell Vpower.

Fastest 201:
1,77sek 60feet
7,91sek 201m

Fastest 402 last year.
1/4 in 12,32sek @ 196km/t

It puzzles me that the engine falls "flat" on its face around 6500rpm loosing almost 100bhp at 6800rpm.

I am keeping the boost constant around 295kpa with the boost controller, so its not a drop in measured boost.

Is this simply the range of the stock cams on a turbocharged B234? Very little heat in the exhaust, so this seems not to be the bottleneck. The boostcontroller does not call for more turbopressure, even at 7000rpm so the compressor seems to be ok. Charge air temp is steady around 36degrees.

I am a bit suspicious on the hydraulic lifters but they are hard to check for. Im running KL racing valvesprings 34kg. The engine maintains around 5bars of oilpressure at 2500rpm and above.

Any good suggestions to get a B234 turbo to rev further up?
mauser240
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Re: compression reduction, B234F + Turbo

Inlägg av mauser240 »

Boosting 2,95 bar on pump gas?

EDIT: Maybe it's MAP?
//MartinL
HenrikGM
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Re: compression reduction, B234F + Turbo

Inlägg av HenrikGM »

295kpa absolute of course.
HenrikGM
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Re: compression reduction, B234F + Turbo

Inlägg av HenrikGM »

Let me just restart this tread regarding the cam question.

I am still a bit puzzled that the 16v isent more willing to rev on stock cams, and am looking for advise.

Normally, a japanese 16v engine, or other 4valved engines i have worked with in the past, tend to like revs even better with turbo, however for some reason i dont see the same on the b234 even with improved flow and better manifolds, allthough is pours out torque as if it wanted to be a diesel.

Currently im on stock cams, hydraulic lifters, kl racing 34kg springs, non adjustable cam gears.

The garrett turbo(from the scania bus, 8,8liter) is a 60mm compressor wheel. That might be near its end at ~560bhp.

So, two possibilities to get more rpm, depending on what is limiting the engine, too small turbo, or too small cam.

Any suggestions?
Looking at an S366 as a potential upgrade, but have no good cam candidate.
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Johan Lindberg
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Re: compression reduction, B234F + Turbo

Inlägg av Johan Lindberg »

Tänkte bara flika in en kompis har en 16v med stroker vev på 2.7l den har han topp effekten på 6000 varv. Den har helt standard topp
turbopleb
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Re: compression reduction, B234F + Turbo

Inlägg av turbopleb »

Henrik, have you tried KLRacing's stage 2 16v cam? It's still able to do hydraulic lifters. I'm planning on running this cam in my engine soon. Should be very good for your power levels. Not sure who is the actual manufacturer for the cams, can't find the site anymore.
HenrikGM
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Re: compression reduction, B234F + Turbo

Inlägg av HenrikGM »

Havenot tried the kl stage2 cam. it would be intersting to hear from some that has.

Some endurance on the valve train is desirable, so i would rather not have a cam intended for drag only, but going for mechanical lifters would be acceptable just as long as the cam doesent wear away the bores in a hurry when cruising around in it.
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