I have a JE 11.5 to 1 piston which produces a psi reading of 215. According to OMR that is equal to around a 12 to 1 piston. Would I see much benefit going to a 13 to 1 or higher compression piston? I've already called CP and they told me they didn't make or have any pistons for the DS any more only the DS450. Where would I even find a new piston with higher than 11.5 to 1?

If it matters I'm running the TM45 w/pump, web 109's, full Graydon pipe w/disc end, HPR ported intake, and a RWR CDI.

 

call RWR they can still get them for the DS up to at least a 14:1

 

I called RW and they told me they had 11.5, 12.5, and 14 to 1 pistons in stock. I told him what the compression test was and what I had installed on my motor. He said that the 12.5 wouldn't be worth it for me and that I would probably wouldn't see a huge gain with the 14. Instead of trying to sell me a piston he basically told me to stick with what I already have. He said the 14 would be an improvement, but the cost of fuel vs. where I'm at performance wise wouldn't be worth it. Maybe I'll look into porting or a big bore.

 

What fuel are you running now?

 

I can tell you that I went from a 11.5-1 CP piston, to a 14-1 Piston from Eric. And the change was night and day. faster revs, lighter feel, and way way quicker. You could not give me free fuel for life in my quad and get me to change back!!!

 

I'm running 50/50 with avgas. He told me I would have to run methanol to use the 14 and that it wouldn't really be worth it for me. I like the thought of a high compression motor instead of a big bore, but I don't want to run meth or alcohol. What kind of fuel/octane can be used with the 14? I'm game for the upgrade, it just didn't sound to good after talking to him. But I'm very easy to presuade!

 

I would say that you would have to run 110 octane fuel if you were to go with the 14:1, and that gas is very pricey. I would say get your head ported and polished and you would notice much more power gains than doing the piston. You already have the carb/ ported intake, the cams, and exhaust. I think a port and polish would help all of those mods shine big time.

 

You are correct, that the head port would work well with those other items. However, he is losing some low to mid with those 109 cams. Who in the world told you that about the Piston??? I run 110 Octane at Sea Level on it, and it is perfect. That other info is crap

 

<div class="FTQUOTE"><begin quote>Originally posted by: DragonDJ11

You are correct, that the head port would work well with those other items. However, he is losing some low to mid with those 109 cams. Who in the world told you that about the Piston??? I run 110 Octane at Sea Level on it, and it is perfect. That other info is crap</end quote></div>

Dragon is right Fo Sho! Of course you can run regular high octane gas. You don't need Methonal or Alky to run High Compression.

 

Whoever answered the phone is who told me that. I didn't really notice the name given? Anyways after reading ya'lls post I've shot an email to The Bom asking about the pistons. If its not a big deal to do it I'll jump the compression up to at least 13 to 1, maybe more.