Yes, it electronic control. Im not worried about detonation. Im concerned about mechanical overload of the piston, either braking the ring lands off it or flexing the pin and distorting the piston. These stresses are highest at peak torque. It has been surviving at 150ftlb, so i just wanted to maintain that torque(average cyl pressure) higher into the rev range. If i ran 22 Psi everywhere, the cyl pressure could be too high for the pistons.

If i havent sold it, and the next engine is ready, I might run the boost higher till it fails to see how much more headway there is. The risk is I could destroy the turbo in the process.

Very sound consideration better safe than sorry!
Is that 150lbs (ate?) if so its quite a bit of torque 25lbs over most stock 2ltr engines on average but if it is at 150lbs ate maybe with the e85 a bit extra is possible and tempting. In comparison 75mm vitara pistons which seem weaker than the A series pistons can handle 24lbs for years on 91 pump fuel.

Around 45-50kws @ the 3800-4000 rpm mark should make a nice safe difference?

The 150FtLb figure is derived from torque at the axel, divided by the diff ratio. so its like the engine torque, but not including the driveline losses.

What engine has been running 24Psi for years with vitara pistons?

The Honda D16 engined civics & integras run 75mm vitara pistons as its a cheap decomp and a tried formula.

I wouldnt like to run any engine at 24Psi on 91 unleaded. Are you sure this info is right? How are the pistons weaker than the A12 ones?

http://turbod16.com/
The US Honda guys get lower quality fuel & the Honda d16 is legendary with vitara pistons, pretty much anyone running boost goes for Vitara pistons rather than forgies.
The common hp w/ pump 91 was around 300-380hp when I last checked on 24psi for safety but now over 450hp atw with over 25psi. I cant find the threads of the d16 dailys running 24psi but a few where running for 4 yrs+ w/ vitara slugs, here`s one thats going close to the hp mentioned but there are heaps & obviously w/ better fuel quality.
http://hondaswap.com/forced-induction/vitara-d16-73748/
eg. Vitara slugs record in drag racing 635whp/421tq @ 38psi
http://www.clubcivic.com/board/showthread.php?t=190923
The quality of vitara pistons used are chinese made not japanese cast ones which should be better also vitara pistons are 28.5 or so comp height not over 30mm like A series. Also another thing to consider is the 4 valve notches weaken the vitara pistons unlike the A series with often dont have any like on the E15ET pistons with are also used on low comp A14 and A15 engines where fuel quality is low. Lastly rings on the Vitara are very thin & almost halve A series. Eg. g16b 1.2mm, 1.5mm, 2.5mm versus A15 2mm,2mm,3.5mm (cant remember but A series are much thicker) have to check acl catalogue for accuracy.

In Australia, Listed octane ratings are RON. In the US, the ratings are RON+MON/2. The MON figure is a much better indicator of detonation resistance.
Therefore, The 91 rating in the US has a much higher resistance to detonation than the 91 rated fuel in Australia.

With the Vitara pistons, im interested in knowing the pin size, the ring land width, the crown thickness, and if they have slots or holes for oil drain back behind the oil control rings. These are the things that will give an indication of strength (and material of course).
I understand some of this info is hard to obtain without having a sample, but do you have any more detailed info?

This might give me a bit more confidence to raise the boost again.

I get a bit worried when you post things like, "24Psi on 91 unleaded for years on pistons that seem weaker than A12 ones" without knowing or posting all the facts. In the link you posted, they say the Vitara pistons drop the comp ratio a heap. This combined with higher octane fuel obviously helps them live.

Im aware of the diference in octane rating systems and such. I just wouldnt want anyone to think they could run 24Psi+ on an A12 with 91 RON unleaded.

Quote:

That is one of the most obscure statements I have read on this forum.

So what? the Vitara aftermarket pistons can take a decent walloping and they are dirty cheap. Apart from those two statements there isn't much more to it.

Oh deary me, the two of you have just completely wrecked this thread. Seriously guys, the two of you need a time out, and I hope a moderator/admin person will clean this up!!!

I think that the moderator has thank goodness.
Simon, I have been at home over the last few days looking over this thread ( and watching the youtube vids ) and I have to say that its truly inspirational.
Some ( 20 odd ) years ago I had a turboed A14 in a 1200 4 door and even now, years later the performance of that car is still a strong memory.
Back then I used a steam pipe "J" off the exhaust manifold on which sat a T2. Interestingly enough an inlet manifold not too dissimilar to what you are using. It had an early Link fuel only computer with the distributor locked up at 28degrees. All very primitive but the point being that even a setup like that went like stink ( 13.7 @ 107mph through a quarter mile) and to be honest I am not surprised that even with 200 odd less capacity you are making the sort of power that you are.
One question that does come to mind though is that I did have a problem with "tracking" between 2 and 3 cylinders when using a standard head gasket- are you using somethng clever or just a standard type one?
Dave