turbo swap ca18-300zx turbo

Ok guys, i'm in the proses of replacing my engine bearings and though wile the motor is out i might as well give the turbo a once over seeing as i did get a bit of morning smoke when it was cold. after trying to find turbo seal to no avail i decided to drop in the 300zx turbo i had lying around after we put ball bearing turbos in the z.

i doubt anyone will find interest in this thread but maybe it helps some trying to do a similar project.

The only difference between the two turbos is the exhaust housing, the z turbo has i slightly smaller exhaust but still the same intake, i'm hoping it'll cut down the lag a bit.
I'm pretty sure at worst i'll need to fabricate is a new down pipe but hopefully i can mod the existing one.

Any case let me get back to work, post some pics tonight.

it might also drop off on power a little earlier than the stock turbo too, if the exhaust housing is smaller!

veecee wrote:

it might also drop off on power a little earlier than the stock turbo too, if the exhaust housing is smaller!

it will

300zx turbo's has a substansial smaller exhaust housing and turbine than ca18det.. not good.. you want bigger..not smaller

When you think VG, think about one turbo powering a 1500 engine, then double it. but if you're still goin that way= NO LAG 😀

I'm not to worried about the power drop of, i'm pretty sure it'll have less lag besides, it's done. i put it's brother on a 2l 8v golf and it doesn't really run out of juice.

Rather than horsepower i'm tuning for response and seeing as the intake is the same i doubt the power drop at higher rpm will be more the what is caused by the additional restriction on the exhaust. the other side of the coin is that with the smaller exhaust air will pass over the turbo with much higher force, spooling the turbo at lower RPM hence increasing the response.

in attempt to minimize the restriction i did however flow the manifold and down pipe(doubt it'll do much but hey, i had the di-grinder handy).

Any case, here's the pics.

I'm not to worried about the power drop of, i'm pretty sure it'll have less lag besides, it's done. i put it's brother on a 2l 8v golf and it doesn't really run out of juice.

Rather than horsepower i'm tuning for response and seeing as the intake is the same i doubt the power drop at higher rpm will be more the what is caused by the additional restriction on the exhaust. the other side of the coin is that with the smaller exhaust air will pass over the turbo with much higher force, spooling the turbo at lower RPM hence increasing the response.

in attempt to minimize the restriction i did however flow the manifold and down pipe(doubt it'll do much but hey, i had the di-grinder handy).

Any case, here's the pics.

there's the size difference you guys were talking about.

the intakes are identical, in fact i ended up swapping them

intake is swapped

job done, now i just got to do the bearings, drop the motor back in and test drive!!

i would be interested in hearing your driving impressions,let us know.. 8)

300sx wrote:

i would be interested in hearing your driving impressions,let us know.. 8)

Yea we can do a run with my SX and we can check the differences.
My SX is stock

Yea we can do a run with my SX and we can check the differences.
My SX is stock

Sounds like a plan... But what's your idea of stock?

Q-mech wrote:

Yea we can do a run with my SX and we can check the differences.
My SX is stock

Sounds like a plan... But what's your idea of stock?

I got a cone filter which slows my Sx down and a leaky BOV or so I suspect and heavy 18's.

The first impression driving the car i wasn't too impressed. then i fixed the boost pipe that popped off and holly shit was i impressed!
in second gear at 2000 rpm you floor it and the ass almost immediately overtakes you. i can shift at 3500rpm and be driving in boost all the way(and i have no dump valve).

Normal driving means i don't need to depress the accelerator more than quarter taps to pull off and i'm almost alway driving in boost.

There is no noticeable drop in high end power but i do tend to shift earlier now as i don't need to rev it as high too keep it in boost for the next shift.

My overall impression on the swap is 10/10 if you want response.
If you want power gains you'll be better of contending with the lag on a larger turbo.

My overall impression on the swap is 10/10 if you want response.
If you want power gains you'll be better of contending with the lag on a larger turbo.

thats about spot on, as to what can be expected. just as a side note, remember that the smaller turbine and integral wastegate combination might have trouble controling max boost, also the max speed of the rotating assembly might be exceeded, resulting in failure or shortened life because of overspeeding.. guess you are just gonna have to wait and see.. 😉

props for trying it out 8)

300sx wrote:

My overall impression on the swap is 10/10 if you want response.
If you want power gains you'll be better of contending with the lag on a larger turbo.

thats about spot on, as to what can be expected. just as a side note, remember that the smaller turbine and integral wastegate combination might have trouble controling max boost, also the max speed of the rotating assembly might be exceeded, resulting in failure or shortened life because of overspeeding.. guess you are just gonna have to wait and see.. 😉

props for trying it out 8)

Well i'm boosting 1.1bar and i'm not really seeing any noticeable erregularities at high boost. it boost earlier and the pressure builds more gradually which makes it feel more docile. as for the life of the turbo, that remains to be seen, i do however have two GTR turbos as spares one of which is going on the MG i'm building.

I guess only time will tell, but for now i'm having a ball!! 😂