bobhatton wrote:Dangerous wrote:Strange.
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.fensport use 8:5:1cr in thier celica
( I asked em today) if bobs theory is right that it does cause to much heat.
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Could this contribute to block failure
?
( I'm on my 3rd
) 2 bar boost on a t04z max lasted 2000miles then went pop!!! Engine builder seems to think that it will make less power with lower compression.
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If you, Gav, or anyone wants some more info please pm me your email address and I will sent it to you.
The only way to run a higher boost without lowering the CR is using race fuel or by backing off timing.
When Toyota changed from the Rev 2 to Rev 3 and increased the boost what did they do, back of the timing? No they spent lots of money and had new pistons made with a lower CR, because its the right way to do it.
Bob
i totaly no what your saying bob and i agree with what your saying but i cant get my head around the fact chris and andy and a few others are runnin 2.5bar with no problems, i have spoke to tb,rogue,fens and so many others they all use the 8:5:1 c/r instead of 8:0:1 c/r i dont get it?
i fowarded the thread to tb
Reply
"yes that is true that retarding the ignition means the exhaust gets hotter, valves etc.
You also loose power but not that the power you want to run mate or compression ratio.
If we were having this descussion at 800bhp then yes i'd agree but were not so hes taking what hes saying as a technical limit not experienced.
"
"I mean for an exampled something Xxxx was playing with was High compression engines.
i believe he tried 2.4bar of boost on a gt4094r turbo
(huge) very high redline and made over 800bhp at compression ratios nearing 10.0:1 and all that happened was the block cracked because of stupidly high cylinder pressures.
So the failure was block strength in this case over fueling limitatons etc which is his argument.
"
"look at dave redeyes gt3076r running 1.3bar on some custom pistons that aren't allowed to expand or they xxxx up and hes making 450bhp with plenty more to come.
pump fuel and lots more ignition advance avalible etc.
Think this goes to prove my point.
"
"not trying to knock the guy, i'm sure hes very nice and knowledgable but proofs in the pudding, i've had people waving bits of papers at me before and seen them make the most stupid of mistakes, and his comments so far show a lack of experience with 3sgte tuning, but a good technical info"
"Like i said, what he is saying isnt wrong, its all just a little premature if you'd have said 600-650BHP in your question, then yes, id agree with him 100%
"
i just dont understand how there can be two diffrent points of view on this i have always thort to run more boost you have to lower the c/r, as bob said the rev2 was 8:8 and the rev3 was 8:5 man i am confussed
](./images/smilies/eusa_wall.gif "Brick wall")
but good news!