How much boost can 9.5 Compression Ratio Pistons?

The 1UZFE EGR Delete Kit is available for sale here.
Thanks Steve,

91 octane is what we get. So dyno numbers from under should factor it out. 500 rwhp from a 98 octane is different from 500 rwhp from a 92 octane. Thanks Justen for clearifying.
 
how is that? RWHP is RWHP regaurdless of the octane used. Octane is only a rating number as to how fast the fuel will burn per given volume. The higher the number, the slower the burn.

The hole point of the tuning with different fuels is to adjust the timing based on other input factors like heat to where the peak BMEP (Brake Means Effective Pressure) or easier stated is Peak Cylinder Pressure is at roughly 45deg. ATDC. This is because this is where the piston and rod have the most mechanical leverage over the crank. To far before the 45 deg. point and more likely to detonate and also puts added loads on rod bearings plus a lose of power due to less mechanical leverage and to far past the 45deg. point and EGT's skyrocket and lose of power due to again less mechanical leverage.
 
What David was probably trying to say is that pulling 500 RWHP out of a motor running on the 92 octane oxygenated swill that passes for premium in the USSA, is a lot different than pulling it out of a car running on "real" premium.

There's just no "headroom" left for mistakes when running on our stuff.

John
 
If thats what dave is trying to say then ok yeah I follow now and yes the lower the octane is, thel margine from error. No if's, and's or but's about the.
 
I think David meant "500 rwhp from a 98 octane is different from a 500 rwhp from a 92 octane" is because he meant the potential of power when the same engine is used with different octane. Of course, a tuning will increase more power with higher octane, but the engine still gains a few addtional hp with higher octane without tuning.
 
not true about gaining power with added octane if the tuning is correct to begin with. If everything is correct, you will actually loose power by going up in octane cause you slow down the burn rate and there for the pressure rise is slower and happens latter in the cycle. You will also loose fuel economy if higher octane is used and not needed.
 
Interesting ....loose power and economy with higher octane..i acturally feel more power when Im on 95 ron than 92 (here in Australia) and have better economy on 95ron,gonna try 98 see if that is better still..
 
isnt there something that the car is close to detonation now adays with the knock sensors allowing it to operate just short of detonation and constantly pullilng timing?

So the computer routinely retards timing to eliminate detonation. If you run higher octane I belive the computer is no longer on the edge of detonation so it may advance some timing. This might account for the increased power.


But what do I know?
 
I an example of a 100% stock car, the system is tuned based on a particular fuel and is recomended by the manufacture. Yes the knock system is used to prevent detonation, but is there for safety in the event that either you accidently put lower grade fuel in then what is called for or if you get bad gas. Like a case here in my area recently where a new dumb ass fuel tanker guy dumped several thousand gallons of 87 octane in to the 93 octane tank at a local gas station and no one realized until a couple of days later.

A cars computer has a timing map with a maximum amount of advance based on engine conditions and will never advance more then that. This map is also done for one intended fuel. If the conditions call for lets say 30deg. of advance then thats what it does unless detonation accures then if it has a knock system then will pull timing, but will never advance more then the conditions call for based on the timing map look-up table.

I have done this and you can also, take a car that calls for 87 octane from the manufacture and run it on a dyno a few times with 87 and get an average hp and tq number then fill it up with 93 and do the same, you will see a lose of hp and tq. Also if you did the same thing but driving around and monitoring fuel usage, you will see a drop in MPG with the 93 octane. This is all why when doing any type of quote unquote tune-up work to a modern computer controled car, setting base timing is very important and the only way that you can run higher octane fuel then originally called for and gain power is to advance the base timing. If you advance the base timing then all total timing will be advanced by that same amount. i.e. if originally case for a base timing of 10*BTDC and you advance it to 12*BTDC, then every point on the map will be 2*'s higher this is because the map table is added amount to the base timing. The problem with most modern cars is that you can not change the base timing as it is locked from the factory
 


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