SOHC vs. DOHC "modability"

[wrigh003]

OK, I know there are a ton of people who know the answer to this here- and I already searched and couldn't find what I want to know, so I'm ready for the flames if they come. That said:

What's the difference in how the 1991-on DOHC engines respond to modification as opposed to the 89/90 SOHC engines? I know the DOHC will ultimately be a better all-around engine, but is there a point at which the SOHC and DOHC engines sort of "break even" as far as power output is concerned? In other words, what's the ballpark HP output of a DOHC engine with basic bolt-on mods, vs the same mods on a SOHC engine?

I'm asking because I'm looking at buying a 240 soon, and am wondering whether I need to keep looking until I find a DOHC example,or if the earlier engines are in the same ballpark of potential.

Thanks for any info-

[andrave]

you said you searched but I doubt you put much effort into it since this has been covered a million times. If you are going NA, the sohc may have an advantage since it has lots of aftermarket parts for. but thats only if you are building the engine. leaving most of it stock they are gonna end up in about the same place. Same for turbo.

[misnomer]

I've frequently read that the SOHC for NA tuneability, aside from having generally more aftermarket, also has an easier head to open up for freer airflow, something limited in the DOHC.

Basically, either engine is quite capable. I don't think anybody has explored the absolute limits of either KA

[Nismopu]

Talk to Rebello's Racing. I think they have explored bothends of the spectrum.

[wrigh003]

Originally posted by andrave
If you are going NA, the sohc may have an advantage since it has lots of aftermarket parts for. but thats only if you are building the engine. leaving most of it stock they are gonna end up in about the same place. Same for turbo.

I'll probably start NA, then when I get everything else I want sorted out on the car (suspension, tightening up the 10yearoldcar rattles and squeaks, etc....) either swap engines or add a turbo to what I've already done.

That said, can someone enlighten me as to the benefits of the DOHC engine in a turbocharged application, versus the downfall of the SOHC engine in such an application? Or is it as simple as the DOHC head flowing more air, thus making more power, blah de blah.

To make it as simple as possible, given a choice of a KA24E and a KA24DE for roughly the same price- which one would you choose to build, and why? I myself am leaning toward the DE, just because it has a bit more power stock, and would come in a newer car.

And if my n00bitude irritates you so bad, you don't have to respond, you know.

[docrice]

Well it seems like a simple enough question, but if you were optioned one or the other for a similar price, i'd go with the DOHC. Sure, the SOHC is a capable and upgradable motor, but there is a reason that DOHC motors (in all cars, not just nissans) have gained popularity....THEY"RE BETTER! its obvious from a mechanical standpoint and, since most companies have dropped the SOHC motors from their lineup for better DOHC motors, its obviously the trend for the future. While trends may seem unimportant, they control one of the very important (at least in my mind) aspects of building a motor: parts availability and, more importantly, cost. Since the DOHC is a better, more updated, and more common motor, parts for it should be more widely available and/or cheaper.

I could go on, but if you haven;t made up your mind by now then you might as well do some more research.

And please, SEARCH on the site a couple times before asking, save everyone the hassle of reposting and flaming you. nothing personal, just keeping the peace...

[wrigh003]

Thanks- I'll look around some more. Just wanted to see what some people thought.

I'll search bettAr next time, I swear. :D

[s0ldats]

sohc has a cool ITB setup that comes in a kit (iirc?)

[RedlineRacer]

If you think you are gonna swap to the SR, then just buy a DOHC. Cause you will have to find some power steering lines and put those in when you swap if you buy a SOHC. You wont have to if you buy a DOHC.

[Ghettokracker71]

I love my KA24DE:D according to Travis Berulle from FI-R.com (Forced Induction Racing) has seen over 550HP from the DOHC 2.4 KA engine, hes seen over 350 on stock cams(91 cams of course,but stock nonetheless) I asked him about building me a Ka,for me I'm staying with my trusty KA24DE,she does like to wheez and cough for air and such when you hit around 5000RPMS but,thats easily enough taken care of

[curbhuggerrps13]

yea if u are goin sr dont i meant dont get a 89nor 90 because im doin a sr swap for my older bro and i had to go to the junkyard and pull out a whole ka24de up to get that piece of shit out..its just like a line that loops around and is a pain in the ass to deal with..but i finally got it out and now the swap is gonna happen once our flywheel comes in...but i doubt ur gonna do n e work yet cuz u dont even have the car and u need to build ur body up like someone else anowledge earlier...go for twin cam cuz u will be happoer in the end except that there pretty pricey ...my 93 cost me almost 5 from a dealership because they are hard to find at that time ...but now they are all over...not with hicas though...