I was just thinking today, if I raised the compression on a 91 octane reflash, would I have to run race fuel? Or would 91 still be ok? And would I still get a benefit from the higher compression? hmmm, questions to ask Rob.

 

This is something I have been wondering about. I am wanting to go NA with my car, and getting higher compressions is a step in that direction.

 

I'll be talking to Rob within the next few days (almost have enough $ to reflash), so I'll let you know what he says.

 

Billy is doing this. (Link286XT)

I'll end up doing both pistons and rods, but not before I can get them for a normalized price.

Frankly, I'm sick of this ****:

 

If you're running an NA setup, and this is NOT your track car (read: running pump gas) then IMO it really isn't worth it for you to change to "high compression" pistons. You'll be running at best 11:0 give or take a little and the gain you'll be seeing is simply not worth the time and effort involved. Now, if you are considering going the nitrous route, then I would see why you want to strengthen your bottom end but still you would want to stay away from having a high compression setup.

If this IS your track car (which I doubt cuz' otherwise you probably wouldn't be asking these questions to start with) then you can run much higher than 11:0 as you'll be feeding her race gas all the time. I've seen comp ratio as high as 16:0 with my friend's setup. Then again static compression ratio alone doesn't give you the whole picture, ignition timing, cam phasing, etc etc play a major role as well.

And finally, if this is for a forced induction setup then you DEFINITELY don't want a high CR setup. You'd yield much better result with lower CR and higher boost.

 

how much are pistons and rods going for these days?
do you think it's ok to leave the stock crank?

 

they dont need to be replaced if your going to a run a turbo at about 5-7 PSI max as a daily driver. If your into pure performance then your going to want low compression pistons and intercooler to prevent detonation and run higer boost (10 psi). anything after that your going to need new valve springs, etc..

 

Thank you, that sounds like you know what you're talking about. I'll probably just stick with the NA reflash on stock pistons.