Question About KA24ET vs. KA24DET

[s13conv]

I'm wondering what the advantages/disadvantages of putting a turbo setup on an 89 KA24E would be (as compared to a KA24DE).

One advantage that I see so far is I could use my old DSM Denso 450cc injectors.

Thanks!

[240marcuSX]

the stock compression ratio is better for turbo. but they both do just as good w/ turbo, compare the SOHCs on realnissan.com to some of the DOHCs on here and youll see the numbers are very similiar. im in the middle of putting a turbo on my sohc.

[s13conv]

Do the trannies hold the power?

[andrave]

trannies are pretty much the same... I'd guess it would just depend on the shape yours was in and your driving style

[Trppen37]

are they both iron blocks?? or is it just the ka24e have the iron block...and the ka24de has an aluminum block?

[Kadath128]

I'm pretty positive they both have iron blocks.

[s13conv]

I think so too.

[huguetpj]

All KA24 are iron blocks. Even the new Frontier one's... I think

[240marcuSX]

theyre both iron blocks, and the trannies are pretty much the same when it comes to strength, they both can hold as much power as you can give them realistically, just get a nice clutch and you should be good to go, transmission wise.

[Trppen37]

so what do you think has more advantage??

SOHClower compressionless moving parts

DOHC10 more hp/10 tq?oil squirters

if you wanna add to the argument then go ahread =D

[andrave]

well in your case, 89 motor=ka24E=already in your car.So thats an advantage for it. Really, they seem to make the same amount of power under boost. For me, my ka24E isn't in good shape and a friend gave me a DE to rebuild, so I'm gonna rebuild his motor for some boost then drop it in. One of the disadvantages for the E is the lack of manifolds for it, there are only a couple around. but parts pretty much cost the same between the engines except for top end stuff, which is half the cost for the E since it only takes one cam.

[240marcuSX]

DE:Higher Compressionoil squirters2 cams15 more stock hp

E: lower compression1 cam

theyre both equally capable.

[Trppen37]

DE:Higher Compressionoil squirters2 cams15 more stock hp

E: lower compression1 cam

theyre both equally capable.

an additional cam gives more advantage?? also lower compression is better for turbo correct???

[240marcuSX]

the additional cam in the DE gives 15 more hp, and less torque gain than that. low compression is better for turbo. any other questions you have, you could probably find the answers to in the FAQ that WD was nice enough to write up.

[C-Kwik]

an additional cam gives more advantage?? also lower compression is better for turbo correct???

The additional cam allows the KA to have one more exhaust valve per cylinder. This allows more airflow. The more air you can move, the more power you can make. The DOHC also places the spark plug in the center top of the combustion chamber.

As far as lower compression it depends. Lower compressions can stave off detonation at higher boost pressures, but you lose off boost response and have a less efficient combustion. If you are boosting at a level where the fuel you use is not detonating, I would leave compression alone. Unless you plan on some high boost, especially on street gas, I wouldn't be so quick to lower the compression. Given two motors that are boosting the same amount on the same fuel and neither are detonating, the higher compression motor will make more power. Don't assume you NEED lower compression just because you are adding a turbo.

That being said, I'd still opt for boosting a DOHC KA rather than the SOHC just for the better breathing capabilities.

[Trppen37]

The additional cam allows the KA to have one more exhaust valve per cylinder. This allows more airflow. The more air you can move, the more power you can make. The DOHC also places the spark plug in the center top of the combustion chamber.

As far as lower compression it depends. Lower compressions can stave off detonation at higher boost pressures, but you lose off boost response and have a less efficient combustion. If you are boosting at a level where the fuel you use is not detonating, I would leave compression alone. Unless you plan on some high boost, especially on street gas, I wouldn't be so quick to lower the compression. Given two motors that are boosting the same amount on the same fuel and neither are detonating, the higher compression motor will make more power. Don't assume you NEED lower compression just because you are adding a turbo.

That being said, I'd still opt for boosting a DOHC KA rather than the SOHC just for the better breathing capabilities.

AHHHH this was the answer I was looking for....thanks

[andrave]

um, that doesn't take into account the size of the valve, man.

[stilesg57]

I think the only reason that the DOHC isn't the obvious choice is because of the higher comp. pistons. The DOHC breathes better, has piston cooling oil squirters (these get really important in autox or other situations where the engine is run under heavy load/boost for a prolonged amount of time), has more manifolds available for it, and doesn't have the timing chain weakness of the SOHC.

IOW, if the DOHC had the same compression (read: swap to some lower comp. pistons) as the SOHC I think it would be clear that the DOHC was the preferable engine to turbocharge.

Realistically though, if your goals are only modest to medium (you're not digging into the internals right off the bat), it really isn't worth the pain of swapping the DOHC into a '89-'90 240. But if I was gonna build a serious motor, it would definately be a DOHC.

just my 2c

[WDRacing]

If your staying with stock internals, then there's no need to swap...thats the size of it. At low boost the difference won't be noticeable. But if your building for big numbers, I would go for the DOHC, a variable ton of cam combo's. Of course I guess you could custom grind a single.

You can make really good numbers with either engine. Aftermarket support plays a role as well though. The DOHC has a better following. If I had a SOHC I wouldn't convert. But if I was buying a car new, I would get one with the DOHC.

WD

[andrave]

sohc has great aftermarket support.