Max Boost Sohc vs. Dohc KA

[nissanfanatic]

7psi of boost makes more of a compression ratio change than any pistons you can buy.

[S13 240SX]

the ka24e is much better and stronger and will hold more boost on stock than the DOHC would.. I know because the DOHC ka's suck.. sorry to say it i'm a KA24 man but the DOHC's suck.. I know cuz I had one, and then I got a sohc ka.

[BlackFlag_s13]

And your reasoning for that statement is?...

If you're building an engine with forged internals then you don't really need to ask this question. I would go for whichever is the easiest to acces, in your case a SOHC. Plus if you ever want to upgrade you cams you only have to buy one instead of two

[Iamjohnhayes]

also i dont know how true this actually is but a lot of people have told me that thet sohc head flows better than the dohc. i have heard it from about 4 or 5 different forums / people

[K240]

One thing the DE has over the E is that the DE has piston oil squirters, the E does not. Im not an expert by any means, but wouldnt that help lower temperatures in the block?

[Iamjohnhayes]

well even if they don't the squirters do give better lubrication which is always good

[nismofly]

E is a low end torque monster, i plan on eventually running the GT3071R that Rick mentioned on mine, but im getting a t3/t04e to start

theres a recent thread showing an -et dyno graph, not sure if you saw it but its worth a look, ill see if i can get it to link

[S14tat]

yeah whats up with that? no body is answering that question. does the 12 valve really flow better on the intake stroke then the 16 valve? i guess its possible but wouldn't one exhuast not be enough to evaculate all the boost in the engine?

[nissanfanatic]

One large port flows more efficienty at a single RPM while two smaller ports flow better at a broad RPM range. But sized correctly, either can work very well...

[S13 240SX]

well even if they don't the squirters do give better lubrication which is always good

screw that it doesn't matter.... just use Lucus oil or royal purple oil for the sohc and its all the lubriaction you get and ask for. I use lucus oil all the time on my sohc.

[nissanfanatic]

It doesn't matter....hahahhahahahaha

[Iamjohnhayes]

yeah whats up with that? no body is answering that question. does the 12 valve really flow better on the intake stroke then the 16 valve? i guess its possible but wouldn't one exhuast not be enough to evaculate all the boost in the engine?

its actually 1 intake and two exhaust valves on the sohc

[S14tat]

for real? wow thats alittle backwards. but okay.

[Iamjohnhayes]

i thought so at first too but it does make sense.

[nissanfanatic]

Scavenging effect is what they were shooting for.

[S14tat]

then isn't that more of a emissions reason then pure performance? i guess it can go both ways, the engine needs to work less hard on the exhuast stroke, and gettin rid of more burnt fuel at the cost of less air coming in for the intake stroke.

[Iamjohnhayes]

im sorry i was wrong the pic i was looking at wasof the back of the sohc (yes i am a retard) their are two inktake and one exhaust valve. i realized it after noticing that the spark plug on the ka-e is located on the exhaust side of the head my bad.

[12valveturbo]

the fact that they have different comp. and one runs 15 degrees and the other runs twenty degrees of timing is a factor in the 15hp I wouldnt say one can make more power than the other I think they are both great engines. piston oilers are cool and so is two cams but then so is simplicity. I would just use whatever I could build RIGHT the cheapest.

[veilside180sx]

Oil piston squirters are an easy addition to any single overhead cam. We never took pics of the last one we added them to.

Heck that was 2 years ago.

So if you are building the block I wouldn't let that deter you at all from doing the SOHC.

[S14tat]

haha its okay, we all make mistakes like that once in a while. so now it makes more sense.

[nissanfanatic]

Quote »the ka24e is much better and stronger and will hold more boost on stock than the DOHC would.. I know because the DOHC ka's suck.. sorry to say it i'm a KA24 man but the DOHC's suck.. I know cuz I had one, and then I got a sohc ka.[/quote]Just a follow up for this arrogance/ignorance, I'm pusing 14psi which is prolly right at or a little over 350whp.

[K240]

-Cory those are very nice numbers for 12 psi. Just wondering if your RFL BOV is open or recirculated? Isnt it only available in Vented? Do you have any problems with it? Also, how much did you pay for your Enthalpy tune? How long did it take to recieve it?

Thanks, I'm in the market =]

[nissanfanatic]

Quote »-Cory those are very nice numbers for 12 psi.[/quote]Thanks.

Quote »Just wondering if your RFL BOV is open or recirculated? Isnt it only available in Vented?[/quote]Yes. TurboXS does sell other valves that can be recirculated.

Quote »Do you have any problems with it?[/quote]Nope. Works way better than my Greddy Type S IMO..

Quote »Also, how much did you pay for your Enthalpy tune? How long did it take to recieve it?[/quote]Paid $500 plus I bought an ECU. Took me exactly one week to recieve it after shipping it out via USPS.

[K240]

Thanks for the help. I do have a few more questions-

1. Do you have any stalling problems with the open RFL bov?

2. How conservative is the Enthalpy tune?

3. Ive heard that it is more aggressive than JWT, like less timing is pulled, and it runs less rich, making more power, but it would be less safe for daily driving. What im getting at is, do you think I should go with the JWT for daily driving, or not worry about it and go with the Enthalpy?

4. Is it really that big of a difference? Ive heard of JWT's tunes that run pretty rich, like @ 10:1 AFR...

Sorry for all the questions, im just trying to get first hand experience.

Thanks again for the help. =]