lets say i could get some 9.75's made, what would i need to run for octane? i know that guys with 10.5 have to run 91, so no premature detonation, but if i run only .25 over stock, will i have to go higher? because i have read, and read, and read, that 87-91 is a waste on our stock engines due to our inability to burn the extra carbon chains without a modified ingnition system. and if i have to run higher octane , would it be worth it to modify the ingition so i wont have to worry about future engine build up problems? or should i just go 10.5 and shelll out? and i was thinking 9.75:1 with some new connecting rods as well, so its all durable and worthy of the $$$. this sound good?

 

just shell out the extra money for 91. you may be paying 20 cents a gallon more for the same octane from last week, but going from 87-91 OCT is a $2.50 difference no matter when.

 

You might as well just buy the 10:1 from buschur racing.

WADAD

 

9.75 will be hardly noticeable. Buschur's 10:1, RPW's 10.5:1 or if you can find a set of RRM 10.5:1 would be a better option.

Pistons should be low on your list of mods after everything else for the engine.

 

9.75:1 would be pointless. You'll gain like what, 2 hp? If that?

As pointed out, go big time. Get RPW's 10.5:1 (or RRM, if any sets are still floating around) pistons. If you're paying for a piston install, install some pistons that will make a difference...

 

i know that, i was just sitting around and thinking about it. but how high of a compression ratio can i go before i run into problems? im not familiar with how high i can push it. i could ask my dad, he has 11.5:1's in a 76 trailoring special silverado, but thats a truck, not an econ car. thanks for the advice, which company makes the best pistons IYO?

 

On a lancer you can go as high as 11.5:1 but you will have to run race gas unless you will play with the timing and then you can make it run whatever you want, almost.
10.5:1, the one I have will make you run 93, Boeturbolancer ran 91 and it was fine.
RPW's carry both of the compression ratios but their pistons are made out of different material not very good in resisting detonations but better than stock. I don't know a lot about rpw's pistons but Buscheur's 10:1 will probably be the best. No major upgrades needed and just some better gas, forged and you will be able to run some boost too.

 

So what Greg is sayin is "I've never spent any time researching RPW, but I went with RRM. Therefore RPW must be inferior"

The RPW pistons are at least as detonation resistant as the stockers as I believe they have sourced stock pistons from other vehicles that match our cylinders. If you're getting detonations while NA you need higher octane gas and a better tune. A proper NA tune will be safe for the weakest of pistons and yield good results. Stronger pistons are not going to save you if you screw up an NA tune (nor will they if you screw up an FI tune- but they're better at dealing with the heat from FI, so THAT'S the reason to switch to forged).

Don't go higher comp if you're gonna boost. Period.

10.5:1 is a good place to be. 11.5:1 requires fuel management and timing controls. If you're wanting to play it safe, this is not the route to go right now in your learning curve.

 

What Greg is saying Alchemist is get off my case. I'm not a guru and I'm giving this guy the only info I have.
I didn't have any particular knowledge about high compression pistons but after researching the web and spending hours talking with Boeturbolancer I decided to do it and guess what it's working! Did you spent any time researching RPW's pistons?
I didn't and it probably has something to do with the fact that RPW is not advertising themselves as well as RRM. Note that their price list/product list came out couple of months ago and I didn't know anything about them selling high compression pistons. As much info as I got from their website and web it seems like their product is good. Road race doesn't make any more high compression pistons, Buscher does, and RPW does too. So which one is better? Why won't you tell me Alchemist?

 

Thx for repeating what I have said.

 

ahh, i see. naw, not gonna dick with 11.5's, and ill never be able to afford to boost, but i was thinking on doing some internals one day, thanks for the help!

 

i think alchem was talking about this:
i believe there was a misunderstanding between hypereutectic pistons and forged pistons. hypereutectic pistons are technically weaker, but RPW can get forged pistons from wiseco, ross, cp, JE, etc. which are basically what we run stateside anyways. that would just mean that their forged pistons are just as good. also looking at the limits of boosting on hypereutectic pistons, if you're not gonna go all out from the beginning are you really gonna be boosting more than the 16psi they're rated at? i don't particularly think most people are going to go above 9 at this point in time.

 

From RPW's web site:
"These are 70% as strong as forged pistons and capable of handling boost levels of approx 16 - 18 psi with no problems at all ...".

What Boeturbolancer mentioned in one of the threads on this forum was that the material used to make those pistons is not durable when it comes to detonations.
Sorry for any misunderstandings.

 

But this dude isn't talking about FI.... he hasn't said turbo even once.

As for whose pistons are best- I'll be going RPW 10.5:1 I would go 11.5:1 but I don't want that much of a headache.

I'm not an expert on RPW. But I have researched the bulk of their NA catalog. I know that hypereuctectic pistons are more than enough for NA. Notice that when the discussion of hyper vs. forged comes up, the next thing that is said is "forged handle boost better". So there's really no need to discuss forged if we're talking NA.

I'm not interested in a fight. I came off too harsh above mostly in response to what I've seen as more blind RRM favoritism. Maybe I'm wrong, if so I apologize.

 

sorry. i was using boost limit as sort of an indicator for how much stress the pistons could take and kinda went off on my own tangent. hypereutectic pistons are good enough for the majority of lancer owners IMO whichever path they take.