Ok, my C5 just crapped out today, piston ring...was running a greddy 18g 8psi. I know...not supposed to be boosting the C5, but I couldn't resist. Ran pretty good...that is, until today.
Anyway, I just wanted to get some suggestions on what I should do. Should I replace with some GSR pistons, or go ahead and get some lower CR pistons....if so, what CR do you suggest. OR should I just get new ITR pistons ? This will be hondata-ed.

 

9:1 forged pistons will be fine. CP works, and so will a lot of other brands..

 

Yeah, I was kinda thinking about something like that. However, if I will only be running about 8-10 psi of boost, wouldn't a slightly higher CR piston be okay? I know that it will be safer, but will I lose HP running 9.0:1? Just wondering. Kinda new to FI. Having 10.6:1 boosted was the **** . Any more suggestions? Thanks!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 12345 &raquo;</TD></TR><TR><TD CLASS="quote">Yeah, I was kinda thinking about something like that. However, if I will only be running about 8-10 psi of boost, wouldn't a slightly higher CR piston be okay? I know that it will be safer, but will I lose HP running 9.0:1? Just wondering. Kinda new to FI. Having 10.6:1 boosted was the **** . Any more suggestions? Thanks!</TD></TR></TABLE>

Why would you only run 8-10 Psig boost on a forged build?

 

I have a greddy 18g, pretty sure that 8-10 psi is all it will go...without having to modify it to run an external wastegate....which I would then have to get another manifold for. Could be wrong though... Anyway, piston ring went today, so I am planning to replace pistons, just not sure what I should put in. Probably not going to see too much more than the 8-10 psi. Anyway, thanks for feedback Speed Ind. !

 

bump

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 12345 &raquo;</TD></TR><TR><TD CLASS="quote">I have a greddy 18g, pretty sure that 8-10 psi is all it will go...without having to modify it to run an external wastegate....which I would then have to get another manifold for. Could be wrong though... Anyway, piston ring went today, so I am planning to replace pistons, just not sure what I should put in. Probably not going to see too much more than the 8-10 psi. Anyway, thanks for feedback Speed Ind. !</TD></TR></TABLE>

Since your re-building it with forged internals, any electronic boost controller will almost double your 8-10psi. What is your EMS? And please don't say FMU with today's tech, with AEM, hondata, crome, etc..... You probably could easy run 12-18psi with reliablity, please get is professionally tuned, tuning is KEY!!!!!

 

I didn't realize that I would be able to get that much boost with a EBC. I was using the greddy blue box, but will have hondata s300 w/ GM boost controller after rebuild. So I should get the lower CR pistions? 9.0:1? Higher? THanks for the info. Appreciate it.

 

9:1 with the piston manufacturer of your choice.That will give you some room to grow.The higher comp ratio will give you a little more torque off boost,but not much.

 

I would get lower compressions.

Im going to be trying to build my engine within the next year or so, and I'm going with 9.0:1 compression CP pistons, and Eagle rods. as well as other various things. I have the 18g greddy kit as well, but ill be upgrading to a gt28rs or something a little bigger.

 

Thanks for all the input so far. So, I will be looking into getting some 9:1 pistons. Will I also have to buy rods, or will I be ok using the stock ones? Just wondering, this is pretty much a dialy driver so, will 9.8:1 be more streetable than the 9:1, or is it not really noticable?
Also, anyone got some input regarding high compression setups?
Thanks again.



Modified by 12345 at 2:32 AM 6/12/2007

 

bump

 

It's not bad to boost a c5... it's bad to boost it untuned though.

Typically higher compression will give you less of a safeguard for tuning. I've tuned several 11.0:1 turbo set-ups and they do quite well and will make more power and faster than a lower compression motor does. As far as streetable goes for compression, you won't be able to tell any difference honestly when properly tuned. In my opinion though since you have the motor taken apart go with CP 9.0:1 or 10:1's with the Hondata s300 system. Throw in some eagle rods while you are at it.

 

thanks for all the info!