need fuel upgrade with sohc pistons?

[TheOne]

will i need more fuel if i get the 8.6:1 comp ratio(dish sohc pistons, not flat tops) into a 93 ka24de, as in will i need something to tune it with or things along the lines of that? , this is with other things stock(cept for intake/exhaust, stock header)

[neverlift]

just run premium gas,you should be ok using the dished ones.... ka runs rich stock so you have some room before you hit uber lean but dont push it,take it to a dyno and have a run or two done with wideband o2 to check and make sure your afr's are good.

A tune would do wonders for your setup tho http://www.hybridka.com ftmfw when it comes to diy ecu tunning!!!!!!!!!!!!!

[DjPantsSpecR]

thats what im going to be doing here as soon as my bearings come in. the sohc pistons are in, and im going to be running it on the stock system initially.

i know when we've talked about this before Vinnie had suggested that one should have some 282cc's made out of the 270s from RC engineering for this job.

Bolt on KAs are fairly lean before about 5300rpms. Then its right to about 12.5 to 1. So its before 5300 im worried about, especially with how much leaner everything gets with the intake manifold. Plus we know there is power to be found with jsut fuel tuning.

However, since high compression isnt actually adding more air, its jsut compressing it for more potential, you can get away with out adding more fuel. Granted, at this level of build you already need fuel, so you cant really get away with it.

So its mainly octane you're worried about here. However, ive noticed some high compression Hondas have been running lower octanes to take advantage of the greater power potential of the much faster flame front at higher RPMs. I'm fairly certain you probably wouldnt get away with running any less than 91 without the knock sensor throwing a fit in these cars though

i'm curious to hear anything anyone has to say about their SOHC pistoned DE build

[halnfl]

I put sohc pistons in a buddies 89 de swap with boltons and we installed a nismo fpr and cranked it up to 40 psi at idle and it was running good afr's on my lm1. It's been together for about a year and a half with no problems. He said he ran 87 once and it pinged a little during our 110 degree days in august.

[TheOne]

i been thinkin about findin a cheap safc2 and 370cc injectors to tune with, but currently money is an issue so only the sohc pistons will go in.(engine currently has a spun bearing, why am gettin pistons/rods from sohc, seemed....cheaper and a tad more hp)

hopefully it'll be good without the need for a tune, but i'll get the afr's checked just incase.

[neverlift]

If you need to be budget minded get a megan fpr and do the wiring mod to your stock pump!turn your 270cc's into 275~285ish try not to go past 60 psi tho,you dont want to lean out your last injector(in sequence) I was reading a "study" about how increased rail pressure beyond certain points is more negative then positive. But I'm on the fence(how the hell would a rrfpr work then?). Something long the lines of the rail not holding enough fuel for the pressure blah blah...

I here running less boost more time is the way to make great power,so it would make sense that a great timing map would gain equal power to just adding fuel to the stock setup... just my 02cents tho

also I think the dohc rods are better, someone chime in please..

[halnfl]

to much fuel pressure can make an injector go static. Basically the pental can't close against the seat with excessive pressure.