the SOHC turbo quest

[sil80drifter]

Hey, I am in the (slow but sure) process of turboing an SOHC block (KA24E to KA24ET), and I was wondering if you guys could give me some tips along the way. So far I have a block with 70k miles on it, which is an almost complete engine, just missing the timing cover and some small things. I am planning on having a maximum of 300 HP/300ftlb at the crank (no more than 10psi, no matter what HP/tq that brings), so I'm not doing any major internal work (except for maybe shot peening the rods, because it's cheap :) ). I want to take it apart, clean it, get new (stock) piston rings, clean the head as much as I can myself (inside and out), then hot tank and magnaflux the block to check for cracks and such, and then put everything back together with new timing chain guides/tensioner and cover. I also have a 5spd tranny with around 70k miles on it, so I'll be using it when I can get my hands on a cheap shell (with preferably no rust). I have a friend who will weld me a manifold, and maybe help me with the IC plumbing. I am sort of a on a budget, but inspite what people say when they get mad at "budget performane" I am not really tryign to get unimaginable rsults for no money. Just moderately good performance, while learning something about the engine. Do you have any tips or advice for someone who is planning to turbo the SOHC? My main questions are, what kind of injectors will I be needing (I think around 440cc is ok for 10psi or less of boost, right?) and how will the be compatible with my stock fuel rail? Will I need a custom fuel rail? Which engine menagement system is adviseable? I want piggyback, because standalone is out of my reach. I will probably have a muffler shop make my exhaust piping for me, because it's chaper than buying something like an N1 exhaust, but what diameter should I go with, 2.5" or 3"? And finally, should I get an oil cooler/radiator, because I assume that the turbo will heat it up more than usual, so I thought maybe I'll need one.
Thanks in advance,

sil80

I have used the search function btw, but none of this info has been sufficiently explained in relevance to the SOHC block.

[sil80drifter]

BUMP

does anyone want to suggest anything?

sil80

[AKADriver]

440s will be fine, you could probably even go a little smaller and still keep a safety margin. 370s, stock from a CA18DET will be a direct replacement with the stock fuel rail.

Definitely go with a 3" exhaust.

The problem with piggyback engine management with a turbo is that... IMO if you get decent stuff you're already spending as much as an entry level programmable system like the SDS. But I'm none too familiar with the various fuel system tricks you can use to jam more fuel in under boost.

I wouldn't worry about the radiator so much if you're only planning on 10psi or less. Oil cooler might be a good idea for longevity but it's not necessary... I'd only go for it if you can get one out of a junked car.

[gman240]

It is good to see other people working on the performance of the SOHC engine that is found in the earlier 89-90 240 sx's. I have an '89 with A KA24E and I am looking carefully at my options as to what I want to do with it and what kind of output I am tryin to obtain. Right Now I really want to go the NA route but If I find it will be equal cost or cheaper to Turbo it in order to push the 200+hp at the Wheels I want to see I will definately do it as such. I wish you the best of luck in what your doing as I to am doing my searching for things, and planning the details of my ride. I definately think the 240SX is one of the most fun cars out there...It is good to see other people working on the performance of the SOHC engine that is found in the earlier 89-90 240 sx's. I have an '89 with A KA24E and I am looking carefully at my options as to what I want to do with it and what kind of output I am tryin to obtain. Right Now I really want to go the NA route but If I find it will be equal cost or cheaper to Turbo it in order to push the 200+hp at the Wheels I want to see I will definately do it as such. I wish you the best of luck in what your doing as I to am doing my searching for things, and planning the details of my ride. I definately think the 240SX is one of the most fun cars out there...

[MyFirst240SX]

i was to lazy to read all that but if you want a good bottom end for cheap go to Realnissan.com they have lots of SOHC stuff

[MyFirst240SX]

thats bull**** james you don't know what the **** you are talking about, best Platform to start with as DOHC? sheer ignorance! the sohc has cheaper turbo manifolds, yes i have reseached them, i havn'te researched into fuel manigment systems but for 10 psi that doesn't matter. have you researched the apects of duractions of two cams as opposed to one cam forn teh KA24E to the KA24DE on turbo platforms, NO you havn't so don't talk JAmes.
ok heres my point the SOHC has several good company's backing it such as realnissan.com, and it has a decent' stock manifold from the Z18DET that the DET wouldn't have.
the sohc has Lower compression and has been discussed on fresh alloy as a comabative advisary to the KA24DET on a turbo scale.

disclamor i have dranken lots of Wild Turky 101
but my opinion is this, don't diss what you don't know unless your stupid
James what exactly makes the DOHC better than SOHC just becuase of its two cams of its many More years of servace for the 240SX?
do you think wsithcing engine's would be cheaper? well your wrong if you think so for a turbo platform. i will give you this tho i would Much rather have S15 engine from a 240 than mine SOHC because they seem to be made better but with real nissan having forged is only 800 away name your price for DOHC short block with FOrged pistons, etc?

[DamnedButDetermined]

James,
I am very impressed by the way you handled that, but i would be very interested as to why you think the SOHC is a lesser engine than the DOHC.

Sil80...
I was going to do the same thing as you, but have decided to just make my SOHC a NA screamer. What is your budget? Even though you are using a cheaper (price only) engine, you will still end up spending about 2.5K-3K dollars on this setup. As far as piggy back computers are concerned, I would go with a trusted brand like ApexI...I know almost nothing about this sort of stuff, but they seem to be an extremely well made product.

good luck,
DbD

[gman240]

I definately suggest looking on Freshalloy. You will find a wealth of infomation on there as reguarded to the Turbo setup of a SOHC. In fact I remeber reading one persons post on there who used the Z18 setuup for his manifold and could give the KA24DET and also SR20DET People a run for there money. Also For those looking to go NA setup The SOHC is the better route. THe Nissan NASPort engines were KA24E's and put out between 200-300 rwhp.... So please do not put down one engine based on your bias'..

[whateverjames]

ignore james. he thinks you have to be rich to make a SOHC fast :confused: please. and the whole lesser platform deal. he's just here to start **** obviously.

so who has ordered or know someone who had ordered from realnissan.com?

[sil80drifter]

guys, thanks a lot for responding, even though it seems a battle of DOHC vs. SOHC broke out while u were at it.
My budget it probably around 2k, or a little less, WITH the shell of the car being gotten hopefully for around 400-800 bucks.
The plan is to turbo the SOHC this summer (as cheap as possible without major skimps), whilst learning about the car/engine, etc and then next year trying to go for a high HP DOHC turbo setup, armed with more knowledge and experience in the turboing process, which is what I will be saving up for, starting the end of this summer and through the summer of next year. So this summer, I'm not really trying to build a ultrareliable withstand all boost, leave me bankrupt motor. Just a fun project. Next summer I'll do all I can to beat the pants off of that guy on unstable-hybrids.com, who to me seems like the bigest ass (I am a common visitor of the nissaninfiniticlub.net forums, and he was a real ass there). Anyway, thanks for your replies. I'll post updates on how things are going...

sil80

[gschroeder78]

Originally posted by James
Now, care to give some un-biased technical info that pertains to the...oh, I don't know....THE TOPIC!!!
Again, why can't you guys save the immaturity for recess?

Correct me if I'm wrong but you have yet to give any "un-biased technical info that pertains to the...oh, I don't know....THE TOPIC"

So please unlighten us all. I'm actually interested in hearing the real flaws of the SOHC.

Garrett

[240racer]

I only have one really concrete reason why the DOHC is better then the SOHC, the others are speculation and in general true. The real reason is: The DOHC head has no lifters, rocker arms or any other unnecessary valvetrain. This is good!!! The cams pretty much just push on the valves. If you want extra valvetrain get a small block, because they make much more power cheaper.

The other reasons like, 4 valves are better then 3 and two cams are better then two are up for grabs. However, the 4v head has more valve area and probably flows better (haven't tested it)

As far as manifolds go, there are more available for the DOHC, sorry.

Also, 10 psi can probably work with the stock pistons (especially if you have the low compression motor) but you have to be very carefull to not detonate or they will melt.

[gschroeder78]

Thank you 240racer. That was actual information that shows why DOHC may be better than SOHC. Alot of that stuff I didn't realize. Thats all I wanted to hear James. You couldn't even give that information when I asked you for it so don't be too quick to say people on this board don't know anything.

[gman240]

I think it is good to have an opinion on which engine you want to use. Plus it is also good to be able to share the technical infomation on building a set-up. But just dont let it turn into a flame-war. Each engine has its ups and downs. And it just needs to be remebered that almost anything is possible when you put the time and research into a project. As I see it the different and varied options make the community better. Be it those who Go NA, those who want to turbo the SOHC, Those that do the turbo KA24DE, swap to an SR, or even go the distance to put an RB series engine into their car. When You look at the 240sx in General I see that as just being a good starting base. It serves to be the canvas if you would and it is given that each artist will create something differen with that canvas. My thing is keep going and lets just continue to see how many different variations we can come up with. Awesome to see the work that goes into some of these nissans like when in one magazine I saw a 500+ hp 240Z using an L series engine and a rotory powered 510 pushing 300+hp as well. So keep it coming and GOOD LUCK!!

[MyFirst240SX]

How about those datsun 510's with KA24ET's running 9's and 10's :) and hey James sorry about being a dick earlier.
You can do real cheap turbo kits of SOHC.
whats the cheapest turbo manifold for the DOHC? the cheapest ive seen for SOHC is 250 with no external wastegate hole.
sean