11.6:1 pistons

Post by **JAESPEED** » Sat Apr 19, 2003 7:23 am

anyone using these?how do they perform?any reccomendations?

Post by **Open4Cycle** » Sat Apr 19, 2003 7:23 am

I don't have them in my KA24DE yet but I do have a KA24E running at 11:1. There is a good performance boost here but your looking at more than swapping the pistons. You will have to richen the full mixture. At the moment I'm running stock fuel curve and pressure settings and I have to back way off the ignition timing to keep from pinging on 93 octane. I recommend deburing all sharp edges inside the combustion chamber to decrease the chance of having hot spots that preignite the mixture.

Post by **SSS** » Sat Apr 19, 2003 7:23 am

Open4Cycle: Have you been in the position to run it on 98 octane or higher? I may be considering such a compression ratio as here in oz our maximum pump gas octane is 98, which i run all the time.

Post by **JAESPEED** » Sat Apr 19, 2003 7:23 am

AH HELL, I CAN BARELLY GET 93 WHERE IM AT.

Post by **SSS** » Sat Apr 19, 2003 7:23 am

Fair enough. I think to be safe, i'd run only 10.6 CR pistons unless you're going to a standalone ecu.

Post by **JJ240** » Sat Apr 19, 2003 7:23 am

you dont need standalone. You need more fuel and everything that is necessary with more fuel. Higher lift cams, header, exhaust. An SAFC would work for adding fuel instead of standalone.

Post by **SSS** » Sat Apr 19, 2003 7:23 am

I guess. Would anyone consider running a Greddy E-manage on an all motor setup?

Post by **I am Technoman** » Sat Apr 19, 2003 7:23 am

A greddy E manage is a great idea! You can tune youre air/fuel curve for what you have done to the motor and you can also use a Z32 MAF to get in more air.

Post by **JAESPEED** » Sat Apr 19, 2003 7:23 am

DOES ANYONE KNOW HOW TO WIRE A Z32 MAF TO A KA??????

Post by **JJ240** » Sat Apr 19, 2003 7:23 am

I believe you have to have a piggyback system or a retuned ECU to read the different signal from the z32 maf

Post by **Open4Cycle** » Sat Apr 19, 2003 7:23 am

SSS I have used some Octane booster they sell here at autoparts store that should have boosted to around that but it didn't seem to make any difference. I'm upgrading some valve train parts and as soon as I do I will mix up a good 14 gallons of fuel (home brew) and let you know.

Post by **raging panda** » Sat Apr 19, 2003 7:23 am

Aren't the 90 pistons a lowering compression in the DE? I heard that the 89s are 11.1 in the DE and the 90s were 10.6 in the DE. Can anyone confirm this?

Post by **JJ240** » Sat Apr 19, 2003 7:23 am

No i dont believe that is accurate. early 89 pistons will give 11.6:1 in the DE, and later 89 and 90 will give 11.1:1 in the DE

Post by **Rownan** » Sat Apr 19, 2003 7:23 am

JJ240 wrote:No i dont believe that is accurate. early 89 pistons will give 11.6:1 in the DE, and later 89 and 90 will give 11.1:1 in the DE

Correct.

I am running 11.6:1 pistons milled down to 11:1 compression in a KA24DE, ECU is tuned by JWT, timing is forced at 20. I am also fine tuning with an S-AFC. Car runs flawlessly on 93 octane, but NOTHING LESS!

No level of timing will allow you to run 11.6:1 on pump gas. It will not happen, which is why I had to back down my pistons a few steps..

Timhttp://www.projectaspec.com

Post by **raging panda** » Sat Apr 19, 2003 7:23 am

So running 90 pistons will give me the same 11.1 as your milled pistons right Rownan?

And Rownan, I read your mods list on your link. What kind of horsepower are you running with all those mods?

Post by **SSS** » Sat Apr 19, 2003 7:23 am

Is starting the car difficult with 11.1:1 comp ratio?

Post by **Rownan** » Sat Apr 19, 2003 7:23 am

Actually my pistons are closer to 11:1 than the 90 pistons are.

I can't be sure of actual horsepower numbers, previously it was running 180 to the wheels but I've done more work to it since and haven't had the chance to have it dynoed. Nor have I had the chance to properly tune the S-AFC. I'm confident though that it is pushing over 190 now and after more reliable tuning is done I hope to break 200rwhp without a problem.

BTW the car starts up perfectly. Ask me again though after I drop some even more aggressive cams in it.

Post by **SSS** » Sat Apr 19, 2003 7:23 am

How aggressive? in excess of 280 deg duration int/exh?

Post by **Juiceit** » Sat Apr 19, 2003 7:23 am

11.6:1 is stock????? i thought 9.1:1 was stock and if so where did u get the pistons i want them

Post by **Touchdown038** » Sat Apr 19, 2003 7:23 am

11.6:1 is not stock for a KA24E... what he was saying is that if you took the pistons from an 89-90 KA24E and dropped them into the KA24DE, ie the motors in the 91-98 240s, you'd have 11.1:1. I'm not sure what he means by early 89 models though.

PS. Stock compression is 9:1 (correct me if I'm wrong)

Post by **Juiceit** » Sat Apr 19, 2003 7:23 am

ok but now where do i get the 11.1:1 pistons i want them Quote »240SX soon to be a 383sx [/quote]

Post by **Movingviolation240** » Sat Apr 19, 2003 7:23 am

the '89 had 9.5-1 stock and the '90 had 9.0-1 but those pistons in a DE will give you 11+ comp numbers.

Paul

Post by **Juiceit** » Sat Apr 19, 2003 7:23 am

ok i understand this but where do i go to get theses higher compresion pistons? i have all of the extra things i need to go faster like header with full exhaust system and upgraded fuel system like pump and regulator. a worked intake manifold. i want the high compresion pistons where do i get them? Quote »240sx Soon to be a 383sx[/quote]

Post by **Stock-S13** » Sat Apr 19, 2003 7:23 am

i could have sworn i read somehwhere maybe JNM said the pre 11-88 240's came with 9:6 compression ratio and all other 89's came with 9:1 compression given that that pre 11-88 had flat top pistons.. i could be wrong but that was my impression on that matter, which worked out pretty horrible for me seein as how i checked mine out and it said 11-88, off by a damn month. oh well it's ok i guess...but i could be wrong someone like to clarify that at all?JNM?

Edgar

Post by **TrunkMonkey** » Sat Apr 19, 2003 7:23 am

early SOHC's (before engine serial #012039) had 9.1:1 compression. everything after that (late 89-90) had 8.6:1.

do a search and you'll find all the specs. i've even posted the nissan service bulletin some time ago that explained the drop in compression.

-demetrius

Post by **Rownan** » Sat Apr 19, 2003 7:23 am

Juiceit wrote:ok i understand this but where do i go to get theses higher compresion pistons? i have all of the extra things i need to go faster like header with full exhaust system and upgraded fuel system like pump and regulator. a worked intake manifold. i want the high compresion pistons where do i get them?

You can get them through Nissan. Nissan motorsports USA actually sells oversized SOHC pistons.

11.6:1 pistons

11.6:1 pistons

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