1sikek9

I'm running a B18c Bored Block to 84.5mm Open Deck with a Precision GT-35R with the High Output housing.... I have yet to deside on on a low compression Piston dont know How low I should Go. If Either a 9:1 or maybe 8:1 ...... I want to Hit around 600whp...... Need Help Deciding which Compression Ratio I should go after......?

1sikek9

No Luck on Piston Compression

96 GSR-T

9:1 is what the majority of us run for street/strip cars

JDogg

what kind of gas do you plan on using?

brian...

11:1 on e85, would be a lot easier to get there. Only have to run about 20lbs or so.

96 GSR-T

Ethanol isnt Methanol, I would rather run 10:1 and run 1-2 more lb of boost then run 11:1. When I tear down my engine I will be going back to 10:1, I only feed my car corn and racegas so I thinks its worth it.

What variant of the 35R is going to make 600wheel at 20psi?

JDogg

if you want it to last the lower the compression the better. 8-9 to 1 for pump gas... i include e85 in that simply because you never know the exact octane you are going to get. e85 is good for a good ammount of power just by itself there is no need to push it with more compression

96 GSR-T

I can pretty much guarantee you Ethanol or any variant of the blend is going to be 100 octane or above. Like I said I will be going back to 10:1 and I plan on 30+psi, I am not worried at all, it all in the hands of the tuner. I want the most responsive setup I can get, 10:1 is going to help me with that.

1sikek9

I would Love to Run some C-12 racing fuel in it...... Also trying to boost as High as 30+psi.....Just Undecided with either a 9:1 ariars Pistons or If I can find 8:1 .... CP or WISECO Piston...... With a 100 shot of N.O.S

96 GSR-T

If they are shelf Wiseco's some people have experienced piston failure in the 650whp region, this is the reason why I am tearing down my motor, I run shelf Wiseco's and it has me kind of worried.

JDogg

the only problem with shelf pistons at high power is the wrist pins... that goes for any mfr.

IMHO there is so much power to be had w/a custom piston especially when you are talking over 600hp, that I would never build a 600+ hp motor with any shelf piston.. spend the 150-200bux and get a custom unit.

for a typical 600hp build I'd use shelf wiseco's w/upgraded pins. that will handle whatever you want for the most part. If i think it will be going more than 650 its gona be custom.

96 GSR-T

The shelf Wiseco has a different design than other pistons like JE and CP, I created a thread about it a few months ago, it is a lighter design piston and good for budget builds. Both Jeff Evans and Tony1 have had these fail prematurely in the 600hp region, I dont remember exactly why but I think the failures were in the wrist pin area and not due to the wrist pin by itself. I never intended to take my setup to where it is now, so I ran with the cheaper Wiseco.

What is wrong with a shelf CP for 600hp or even 750hp? I dont see what needs to be custom other than HD wrist pins which is just an option. What would you recommend to be custom when ordering such a piston? I have gone back and forth for a while now with CP's custom piston rep, and if there are some good idea's in piston design I would like to implement them into my new pistons, as it is now I have to order a custom set due to some tight clearances.

JDogg

when the wrist pin flexes, so does the piston, causing a failure in the pin area....

there is nothing "wrong" with any shelf design, however, there are changes that can be made to the piston that will dramatically increase longevity, power and efficiency. The benefit at lower power levels dosnt really justify the cost for a lower power setup, but with big power 5% is a lot.

any shelf piston w/good pins, race gas and a proper tune will hold damn near whatever power you want it to.

JDogg

nothing "NEEDS" to be custom, but you have no problem spending 1500bux on turbo, whats 750 for pistons that will make that turbo work better.

noone is going to give away their custom piston designs.

96 GSR-T

Oh trust me I had a problem with spending $1500 on a turbo twice actually my first one cooked in 1500 miles.

I didnt ask for someones piston design, just some idea's on what would make a piston better than a shelf unit.

JDogg

different dish design, different ring pack, skirt type, gas ports, ring position, etc, etc........