DOHC pistons in a SOHC ?

[Dustin240]

Have any of you put DOHC pistons in a SOHC? If so please tell how it went.

[deviousKA]

7.5:1 compression ratio

[Chezedik]

Wow, that's less than a 1G DSM Turbo! You could probably pull wicked boost, but what's the point? You won't find a turbo properly sized to make it worth it. The problem will be that for you to reap the rewards of such a low static compression, you will need a pretty small turbo. With this you will need to increase the boost of the turbo to make up for lack of flow. You could use a larger turbo at the 8.5-9:1 and run a little less boost and make significantly more power. Although, it was a nice thought, it really would be a waste of time and money.

[S13 240SX]

wow i'm gonna do that.. dohc pistons in sohc... 7.5.1 C/R.. i'm gonna do that and then installed a holset hx35w turbo.. that might be a good setup.

[wild_maxx]

ya.... if you want terrible low end and off boost drivability... and take forever to spool.... do you have a fully built motor to support that turbo cause they are huge. Then you will need a fuel system to support the turbo..then you will need a managment system to control that... then tons of upgrades to the car itself to handle the power..... have fun.

[S13 240SX]

well i dont know... : /

[BlackHat]

What about higher compression kade pistons in a sohc? That may not be a bad idea just because it's hard finding kae pistons. (Performance ones anyway) Is there some kind of simplified formula to figure out the actual CR?

[Chezedik]

Ealier there was a chart that Devious had up, but now it's just a red x, maybe ask him.

[deviousKA]

Higher compression dohc pistons in a sohc?

Yeah, thats what you need. Not quite sure if you are aware the most common high compression piston for the ka24de, is a ka24e piston.

There was a chart up there, looks like it died.

[wild_maxx]

i just bought a set of (DE) 10.7:1 comp. Arias pistons for my kae motor. I am thinking it will drop the compression around 9:1 ish.. idk for sure.

In my last built up kaE motor i ran (DE) 9:1 comp . SuperTech pistons in my motor.... trust me.. the low end sucked balls!

[deviousKA]

Whats that piston top look like Shawn? Similar to ka24e piston with just a bit more dish?

If it truly provides a 10.7:1 compression ratio in the ka24de (5cc dish), that would be a recommended piston for the ka24e turbo.

Ka24e ratio would be approximately 8.2-8.4:1 depending on bore.

[wild_maxx]

yeah it has a bit of a dish in there but the center of the pistons are higher the and the outsides to raise the comp. they also have valve relief cuts for all 4 valves. the bore is .020" over (89.5mm)

i wasnt aware the comp. would lower that much... but thats actually better.. won't have any problems with detonation.

[deviousKA]

Ok, then all of the dish volume is in the reliefs, should work nicely.

[BlackHat]

Someone might have to slap me if I'm thinking too far off the sanity path, but wouldn't 7.5:1cr be great if someone wanted to try twin charging a kae? put a roots type SC then some massive TC on? Seems like the SC would help both low end and TC spool up....

I was debating trying a SC + TC... but not sure if $$ is even reasonable... Could probably rebuild and fab a VG30DET into a 240 for the price of a KA SC+ TC...

[Greg240]

1g dsm have 7.3 compresion ratio and its not all that bad. 2g dsm have 8.5 compresion ratio and evo's are at 8.8 just so you know.

[95_240sx]

Shawn: They are 10.6, I found the job card.

Rick

[wild_maxx]

ok cool. They will work fine for my application. One question tho... From what i have heard... the star on the bottom of the pistons need to face the front of the engine correct? on the right side of this pic

[BlackHat]

Where are you getting your high cr kade pistons maxx? I can't seem to find them...

[wild_maxx]

there ya go d00d. The pistons i got were for the DE with a10.6:1 comp. ratio. Rick gave me a damn good price that i couldnt pass up. They will work fine for my application. If you order a set just get the ones for the E in whatever comp. you want them.

http://www.ariaspistons.com/nissan.html