need input ASAP

Post by **racerSXtreme240** » Mon Mar 08, 2004 10:19 am

i am currently building a KA race engine for my 240 project, i was originally gonna build a powerhouse NA but money and time have put a damper on that, so its now going turbo... but when i had decided to delve into my NA project i invested in a set of HC forged pistons which will not be used in my proect car for obvious reasons, but i am rebuilding my daily driver 240 as we speak and it occured to me that with my cams and those pistons i could possibly see a decent increase in power, i have read all the piston threads on here but none of them touched on my main concern, which is: If i install these pistons will there be any ECU problems to worry about?.. i seen a post on one of the other threads that a couple of guys were running 11.5-1 with JWT ECU, which i didnt plan to get, so i need to know if i can run 11.5-1 or 11.7-1 compression with a stock ecu and without probs... im not worried about any kind of mechanical failure, the engine is a fresh rebuild with performance gaskets, and the block only has about 50k on it, ive already got I/H/catless E, ported polished and port matched heads an intake, so it is going to be a fairly clean flowing engine, i also still have the butterflies in my intake due to my 248-248 cams, it was the only way i could come up with to save a little of my bottom end, and i must say that i cant tell an extreme difference between them on low end power... anyway, sorry for the novel of a post, i tend to over elaborate on questions, any help would be appreciated... thanks

Post by **TrunkMonkey** » Mon Mar 08, 2004 10:19 am

what octane gas do you plan to run?

-demerius

Post by **racerSXtreme240** » Mon Mar 08, 2004 10:19 am

93 at the least, thats premium here... but i usually run a cheap octane booster anyway...should be fine, right?

Post by **TrunkMonkey** » Mon Mar 08, 2004 10:19 am

maybe if you retard your timing too. i've never seen anyone run that high a compression ratio with the stock ecu, even with 93 octane.

-demetrius

Post by **racerSXtreme240** » Mon Mar 08, 2004 10:19 am

well, im dropping them in as we speak...so i guess i will ust have to tune accordingly... how much retard would u recommend?..dropping it to maybe 18? or lower?... thanks for the help demetrius, today is the first time i have posted on these forums but ive been coming here for some time and was hoping you would be the one to reply on this problem, from what i had read u seemed to be the most familiar...

Post by **TrunkMonkey** » Mon Mar 08, 2004 10:19 am

what's the exact compression ratio that you have?

-demetrius

Post by **IvoryJ30t** » Mon Mar 08, 2004 10:19 am

first off, octane boosters are pretty much worthless. you get a gain of about .3 octane.

on a daily driven car, without forced induction, I would have went with a set of hypereutectic pistons instead of forged. could have saved a little cash since you dont need the strength to withstand high boost. also, the cold start [piston slap] clearance isnt as large with a hypereutectic piston.

does anyone even make hypereutectic pistons for a KA?

Post by **racerSXtreme240** » Mon Mar 08, 2004 10:19 am

Quote »what's the exact compression ratio that you have?[/quote]

sadly im not positive, these pistons for for the ka24e, and were stock compression, but im not sure what yr they were for. so i guess 11.1-1 or 11.5-1 right?... is there anyway i can visually tell the difference?..

Quote »first off, octane boosters are pretty much worthless. you get a gain of about .3 octane.[/quote]

your correct, with most u get very little result, but if your willing to shell out an extra $6-8 for every fill up you can raise your octane by a few points. which isnt fenominal, but effective if needed.

Quote »on a daily driven car, without forced induction, I would have went with a set of hypereutectic pistons instead of forged. could have saved a little cash since you dont need the strength to withstand high boost. also, the cold start [piston slap] clearance isnt as large with a hypereutectic piston. [/quote]

well, had i payed full price for the pistons i would agree, but i got them for very little cash from a friend that had decided to go SR and not build his KA, it ended up costing me around $150 plus helping him with his swap.. and im not sure if anyone makes hypereutectic pistons for the KA or not.

Post by **TrunkMonkey** » Mon Mar 08, 2004 10:19 am

racerSXtreme240 wrote:sadly im not positive, these pistons for for the ka24e, and were stock compression, but im not sure what yr they were for. so i guess 11.1-1 or 11.5-1 right?... is there anyway i can visually tell the difference?..

the E pistons you want to run should have a dish and will give you 11.1:1 compression. this is only if you haven't had an overbore or the head shaved. if you have, then the compression ratio will be higher.

-demetrius

Post by **deviousKA** » Mon Mar 08, 2004 10:19 am

One thing to add. The 89+ ka24e pistons have such a small dish volume, they appear to be flat tops. The dish is appox. 2cc, or about .020" lower than the edge of piston.

Post by **racerSXtreme240** » Mon Mar 08, 2004 10:19 am

ok cool, i was gonna ask how deep the dish was... mine are 89+ then, the dish is very very minimal, and they are near flat top... thanks for the help guys, i have the engine ready and dropped i am currently hooking everything up so i will let ya know how it turns out after a little tuning and testing... i apologize for bringing the piston question up again i noticed all the noobs are askin bout it again, but i really needed to know the ECU question and couldnt find anything on it... thanks again, ill keep ya posted

need input ASAP

need input ASAP

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