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nismodude 08-25-2005, 05:57 PM sorry im a noob and i already tried searching. can you tell me what piston upgrades there are availabe? i know there are 8.5:1 and then theres 9:1 and theres 10.5:1 but the sr20det is 86mm and the pistons are 86.5mm and 87mm. they they bigger cause you have to bore the block or what? what piston is suitable for 91 octane but still be able to run high boost? or even just a decent boost like 8-10 psi? NX$paniard 08-25-2005, 07:05 PM an upgrade in piston would pertain more to what type of material it is made of and how it is made. Forged vs Cast , etc The numbers you are listing are simply compression ratios. They are not considered upgrades but more suited to whatever setup you are running. **NORMALLY** the higher comp ratio you run the less boost and advance you can get away w/ , but you do get better response. The lower comp ratios are used for buttloads of nitrous or high boost applications...response time is greater but usually compensated by crazy hp/tq. there are several good manufacturers who make great pistons for the SR20 in any size from stock 86mm to overbored 92mm. Usually a common upgrade on an sr block is to go to 87mm w/ stock sleeves. Anything bigger than that, you should use sleeves. Best thing to do is use a Forged piston. Lighter and stronger and resist detonation due to their construction properties. Most oem pistons such as stock SR20 and Z32 pistons hold boost fairly well, all things considered. Unless you plan on building a really high HP engine or do some serious racing. Stock pistons should be ok. But if you decide to go forged you can contact or research the following: JWT Arias JE Wiseco Ross CP Im sure theres more but those are in my opinion the best and most common.... Mrs Wicked R 08-25-2005, 07:11 PM Erich uses GTi-R rods and pistons in my car... I did this because Shaggy said so via 500whp dyno sheets... :tongue: Cheers- Sarah NX$paniard 08-25-2005, 08:02 PM GTiR has what... 8.8:1 CR? And yes, GTiR rods are considerably stronger than regular DE/DET rods ;) Mrs Wicked R 08-25-2005, 08:10 PM GTi-r motors have 8.3 due to the head... using the rods and pistions make a DE(T) block an 8.5CR... Cheers- Sarah OnyxEros 08-25-2005, 08:15 PM the gtir rods only fit the gtir crank I assume you have that as well nismodude 08-25-2005, 08:41 PM **NORMALLY** the higher comp ratio you run the less boost and advance you can get away w/ , but you do get better response. The lower comp ratios are used for buttloads of nitrous or high boost applications...response time is greater but usually compensated by crazy hp/tq. so what youre saying is the lower the compression, more boost can be used but then octane is going to have to be higher to give the horsepower? NX$paniard 08-25-2005, 08:57 PM you shouldnt run crap octane on something w/ high boost anyway.. 91 or higher...preferably higher.... Wicked R 08-25-2005, 09:14 PM Yes I do have the GTi-R crank... I'm not an idiot... Cheers- Erich nismodude 08-25-2005, 09:25 PM i plan on using 91 since its going to be my daily driver but i also want a high horse power daily driver. if i go for the 8.5:1 cr whats the highest amount of boost i can achieve on 91 octane? NX$paniard 08-25-2005, 09:49 PM 20 psi should be safe.....if you do it right... you can always mix in some 100 or 110 unleaded w/ 91 just to be on the safe side nismodude 08-26-2005, 04:38 PM that would put me to at least 320 hp if i run 20 psi right? Wicked R 08-26-2005, 04:47 PM that would put me to at least 320 hp if i run 20 psi right? Hell no mang... 20psi should put you in high 300's to low 400's... :eek2: Plan on replacing axles and B13/B14 trannies though... :rolleyes: Cheers- Erich | ||