pros/cons of going turbo KA or SR20?

[jdmfreak]

That S14 is sooooo nice.

[240Knightrider]

yeah it is. I like it cause my mom liked it and is more willing to let me get the SR, which Im getting real soon. HAHA

[ugadawg9524]

out of curiosity, would it be worth swapping to an RB25DET or RB26DETT? i dont know the prices on those engines. what would i have to do to stick a straight six in the engine bay? and my next question is, would it be possible to put an S15 sr20 into a S13 240sx body?

[240Knightrider]

yeah its possible to put the s15 into the s13 body its got the same block I think but am not sure. For a low budget you will have to spend a lot for the RB to get it done right, the first time.

[jdmfreak]

Yea the RBs will probably cost you the most, but all that power is definately worth it IMO.

[Turb0wned]

i dont understand how you people can say that a turbo ka is so much cheaper than a sr. most ka are gonna have 100k+ on them (atleast the 89-96, even the 97-98) why would u go turbo on an engine with that many miles on them? the engine is gonna have to be rebuilt=$$$ then the turbo kit=$$$ you can always by the parts separate and make your own piping but that will still cost for a decent 230-330hp anywhere from 1500-2500 then plus the rebuilt... i got my sr red top just engine and transmission with 50k on it for 1000k needed ecu and engine harness still doesnt come out to more than a turbo ka...

[Turb0wned]

i agree with [s3] fully...

[Nathan]

i dont understand how you people can say that a turbo ka is so much cheaper than a sr. most ka are gonna have 100k+ on them (atleast the 89-96, even the 97-98) why would u go turbo on an engine with that many miles on them? the engine is gonna have to be rebuilt=$$$ then the turbo kit=$$$ you can always by the parts separate and make your own piping but that will still cost for a decent 230-330hp anywhere from 1500-2500 then plus the rebuilt... i got my sr red top just engine and transmission with 50k on it for 1000k needed ecu and engine harness still doesnt come out to more than a turbo ka...

Yeah, but you now have a junkyard motor with unknown mileage If the KA guy rebuilds, then he has a motor that he KNOWS is in good condition and stronger than even your heaven sent SR. Now, why did this thread come back to life? Its been beaten to death at this point.

[marshun]

i guess if you want to be a d!ck about it. they'll come out even. but idealistically you should have done the necessary maintenance on your cars. (water pump, timing chain yadda yadda). and you know how much miles you got on your car.

with an sr20 you dont know how much miles are actually on the motor, you dont know if they motor was serviced regularly. and its a good practice to replace all the necessary maintenance stuff before swapping.

then it all comes back to preference. do you want to just swap the whole damn motor? or would you like to just add turbo?

the main reason im aiming to turbo my KA is because my motor was rebuild about 30k ago. motors in japan dont usually have TONS of miles on them because of their regulations there. so with that in mind, swapping the motor might be better since you might not be able to afford having the car DOWN for a while. who knows what your reasons are. but you should take those kinds of things into considerations before swapping.

im starting to phase out so i dont want to keep goin

[LSB_11]

what about the tech. on the sr, and what about the potential of the sr. i mean you can get the same numbers with .4l less displacement. has anyone ever ran a turboka against an sr with the same hp. we need to set this **** up, see what works better. then we can all have a pissing contest if there is a tie.

[Nathan]

The SR is no more technologically advanced than the KA (at least not the S13 SR's that most people go with). Besides, I've never seen a fair comparison between an SR and a KA with similar mods. My guess is that the KA would simply have more torque down lower and the SR would make the same or a shade more power up high. Area under the curve would be the best thing to measure betweena similarly built SR and KA running similar turbo's, management etc. I prefer the KA for every day driving, its ridiculously easy and cheap to get parts for, and the low down torque is very nice as well. I'm making 150ft. lbs. of torque at 2500 rpms...that makes daily driving quite comfortable and easy One thing that should be mentioned...building up a high power turbo KA is NOT easy...its definitely not any easier than a motor swap, and might just be harder. Its oh so rewarding though!

[gc8936]

:thinker KA-T I have raced my friend with a Sr with the same boost 12psi and I beat him, because of the toruqe I have and his engine is running great. The advantage he has is the Sr can pass me up at 125Mph Cause of the transmission.

[LSB_11]

im not talking same amount of boost, im talking same hp numbers more or less, but then again, how much did each car cost, not to be a d!ck, just curious.

[masticatingcow]

LSB_11,

If you just want similar HP numbers, and assuming that both engines were properly cared for, properly built and whatnot, and assuming that by ""running a turbo KA against an SR" you mean a 1/4 mile drag (which, BTW, about 90% of car owners imagine when they think "performance contest") then you can bet that th KA will win. It's additional .4L provides extra torque, which would give it the edge in a launch.

This discussion has gone on WAAAAAYYY too long. There is no definitive answer. People who ask, "which is better?" need to figure out what they want and pick the engine that suits them best, understanding that the decision really should be a matter of personal preference, NOT popular concensus.

[sil80drifter]

Btw, the trannys are the same. The bellhousings may be different, but the gear ratios inside them are identical. As are the differential gears, unless you are talking about an LSD s13 vs. a non-LSD S13. Still the ratios are close enough to be considered identical even in that case. If he passes you "at 125" there must be another reason for it. Like top end.

sil80

[xxtrizz]

Just thought I would throw two constructive comments in here or more :P

The KA is probably gonna make more HP on the low end making it most likely killer on the strip. The torque is gonna launch that car a littler better than the SR.

But as we all know the SR revs higher. So its gonna make more power at higher rpms because its pumping out 1.5 - 2k more rotations pre minute of the same energy. basically its getting around 1/4 or less power increase because of the higher RPM. Thats how hondas work it :P

Honestly its just what you want to do with your engine I got quoted a killer rebuild for 2500 on a KA and it was forged all around and had some head work done. Hopefully Ill be able to get it done here soon. 2500 = SR from heavythrottle same price my friends

So to each his own, the question is what do you want to do????

[240SXer]

Btw, the trannys are the same. The bellhousings may be different, but the gear ratios inside them are identical. As are the differential gears, unless you are talking about an LSD s13 vs. a non-LSD S13. Still the ratios are close enough to be considered identical even in that case. If he passes you "at 125" there must be another reason for it. Like top end.

sil80

Yes, the gears are the same. But the SR revs a lot higher, thus it has a higher top speed. My KA redlined at about 6400, my SR is 7500. Same gears. SR can do 40mph in 1st gear, the KA can only do 35 or so. (yes, I feel 900rpm is a lot higher)

However, the top speed on a KA isnt 125, it's much higher. Like 145, the top on the SR is like 170. These are redlining 5th gear. I might be a little off, but you see the point.

I'm not hating on either motor btw

[TravisD]

Why doesn't anyone ever quote the redline for the DOHC KA in these discussions? It's 6900rpm. I can see it right now. My tach is sitting on a shelf above my monitor. There's not an *ahem* 1100rpm *ahem* difference necessarily.

[240SXer]

I was quoting the DOHC KA. It's 6400. I've still got the same tach The redline on my 1991 is 6900. So even at the lowest, 600rpm extra in 5th gear is a lot more mph. Hardly a deal breaker. Not that big of a deal, if you want more top-end get Z32 TT rear end.

[Silviapower]

Correct me if im wrong about this?

Isn't KA doesn't have power on the high RPM 5000 to 6500? lets say both motors has 300 HP, how is it possible for a KA to bet an SR that has power all the way to 7600RPM?

Next question is , Let say the race track has a long straight away and both motor will be at the top end of the RPM now what motor u think will last i bet KA will blow and SR will keep going?

All of this is with a stock internals

[Bigrolla]

like i was always told "There is no replacement for displacement."

[LSB_11]

its a four cylinder, your talking about .4L. i know that still more, buta 1.8gsr can put more NA hp down i do beleive. i feel more comfortable with a factory engineered engine being turbocharged then someone making parts to be as strong as possible, these in my eyes are two different things.

[jdmfreak]

Well if both are tuned right then the KA shouldnt blow. In a race of 300 hp vs. 300 hp, The sr will have the straights since it has a higher redline than the KA. If the speed limter on both engines were left on then it'll be a closer race, but if the limiter is off Im quite sure both engines can reach 140 mph easily given a long enough straight. What if the KA-T had ECU and cams done to it to give it a lil more top end? Theres a lotta factors dealing with the two engines and in the end its down to which one has the best tuning. Low-end torque vs. high reving, Id prefer the low-end torque. Its all in the eye of the beholder.

[Bigrolla]

this is a never ending batte. Eithier can be just as good as the next. It all comes down to ur own preference.

[Silviapower]

yup but still i don't see any KA winning a race....hehehe:D . NO history at all cuz they are not up to the task:D

[GlacierFreeze]

Correct me if im wrong about this?

Isn't KA doesn't have power on the high RPM 5000 to 6500? lets say both motors has 300 HP, how is it possible for a KA to bet an SR that has power all the way to 7600RPM?

The SR doesn't make good power up to 7600 rpms, it dies off too after ~6.5k without cams and/or greddy intake manifold.

Quote »Next question is , Let say the race track has a long straight away and both motor will be at the top end of the RPM now what motor u think will last i bet KA will blow and SR will keep going?[/quote]

Yeah if you're an idiot and try to rev the KA as high as the SR can. Seriously though, what's that have to do with reliability? Considering you don't over rev.

[jdmfreak]

Well how bout you venture into the KA-T section and tell that to them. The KA can rev as high as the SR with the right tuning. They might not have as much power up there as the SR, but it sure as hell is up to the task.

[jdmfreak]

Oh I forgot to say that revving up that high isnt too wise. Id say 7200 RPM is plenty.

[GlacierFreeze]

I never said it couldn't rev over 7k safely. But most somewhat highly modified SRs run to 8k with rocker stoppers. Doubt any KA people want to try it that high. And no, I'm not bashing the KA.

Maybe it came out wrong but I was just replying to what Silviapower said. He was sounding like the KA would blow if you wound it out on the freeway or something.

[jdmfreak]

Oh no. I was talking to Silviapower. Sorry for the confusion.