I was talking to a guy this weekend about going all motor (he has a all motor GSR) and he was telling me that I have to replace the rods if I do raise the compression, but at the same time, he told me that if I used CTR pistons I wouldn't have to. Is that true? What would my compression be if I used JDM ITR pistons versus the CTR pistons? He told me to use a Mugen head gasket, but I heard I would run into clearence problems with Spec B's. Is that true? I am trying to get everything right because I plan on starting on this set up really soon.

Thanks! Corey

 

I am thinking about a similar set up - I think (in a GSR) JDM ITR pistons would raise compression to about 11.3:1 - CTR pistons would raise compression to about 12.4:1 (I could be wrong though) - not sure about this but the mugen headgasket would raise compression by .4 with Toda B's & CTR pistons I think clearance is possible (depending on cam timing) but with the mugen headgasket you could run into some issues. I am looking into JDM ITR pistons & and a spoon/mugen headgasket + Sunoco 94 octance gas all the time I also would appreciate others thoughts & experiences - thanks Greg - oops... I just saw you have an ITR take .2 of the compression totals above - sorry


[Modified by 2000-4DRGSR, 8:38 AM 11/21/2001]

 

You dont have to replace the rods, but while your in there its not a bad idea to switch them out for some stronger rods, either probe industries or eagle rods would be a good choice for short money. Or you could just have your stock rods shot peened and balanced, But after you spend the money to do it you'd might as well buy aftermarket rods.
As far as pistons there are Many choices, for the money though JDM ITR or CTR pistons would be a good choice, JDM ITR will give you a 11.1:1 compression CTR will give you a 12.2:1 IMO I would go with the CTR or the JDM ITR and thinner headgasket (Spoon or Mugens) Either gasket raise compression up .3-.4 points So you would have 11.4:1 or so. With the CTR and Spec B you wont have clearance problems, even with the thin headgasket, With C's on the other hand you may run into some clearance problems if you use the thin headgasket, But with any all motor setup the engine should be clayed to check for clearance issues.

PS Stop litening to this guy, he seems to be passing along rumors

 

So, I can get CTR pistons and use pump gas on 12:2:1 right? With that high of compression and thinner head gasket would make it too high for pump gas wouldn't it? The highest I can get is 93 octane here. I can get race gas, but this is a daily driven car. So right now this is probably the set up I will going for then.

CTR pistons, Toda Spec B's, and a thinner head gasket. Spoon or Mugen?

Will I need bigger injectors as well? How big?