GT28 for CA18

S13 T25 vs S15 GT28R

Arno, your new turbo should work well here, albeit a bit later in the rev range.

I suspect the pre tension on your waste gate actuator is not set correctly. Do you have pre tension on the waste gate flapper valve ?

If you do then the turbine side is rather large . Having said this , once the turbo starts feeding on itself it should really wack into boost up to the waste gate setting.

I would not blame the turbo at this stage, look for the problem elsewhere..

I still go with wategate pre tension..

I used to run a TB2804 which is the turbo from a GTiR T28 with 0.86 exhaust.

Mods were dicktator exhaust and filter full boost was at 4000rpm nothing before but held all the way to the redline

BigKriss wrote:

Arno, your new turbo should work well here, albeit a bit later in the rev range.

I suspect the pre tension on your waste gate actuator is not set correctly. Do you have pre tension on the waste gate flapper valve ?

If you do then the turbine side is rather large . Having said this , once the turbo starts feeding on itself it should really wack into boost up to the waste gate setting.

I would not blame the turbo at this stage, look for the problem elsewhere..

I still go with wategate pre tension..

Hi BigKriss, I left the actuator as it was from the factory, I have to stretch it about 4mm before it goes over the waste valve shaft. should I put more tention and try again.

rat wrote:

I used to run a TB2804 which is the turbo from a GTiR T28 with 0.86 exhaust.

Mods were dicktator exhaust and filter full boost was at 4000rpm nothing before but held all the way to the redline

That is even bigger than mine, was it on a CA18?

Like Barry, I still believe your problem lies at the wastegate

Daniel wrote:

Like Barry, I still believe your problem lies at the wastegate

just spoke to the guy that is gonna dyno it for me - he said 4mm is a lot of tension on the wastegate. i checked for leaks now and there is nothing. let me remove the vacuum pipe on the actuator - i will update you shortly.

I removed the vacuum pipe from the actuator - still same result.

I am also of the opinion something is wrong with the wastegate, the exhaust housing is larger and would mean slightly later spool but not what you are experiencing.

2 things I can think of.. 1:I suspect either the wastegate "flap" is not sealing the wastegate hole properly because of angle or the hole is off centre meanaing the wastegate "flap" is bypassed easier.

2: the journal bearings are bighting the shaft for some reason....start the car and let it idle, then look into the compressor intake and see whether the wheel spins....if it doesn't, let someone rev a bit and see if it starts spinning....that could mean that something is bent ot wrong not allowing free spooling....

Draco wrote:

I am also of the opinion something is wrong with the wastegate, the exhaust housing is larger and would mean slightly later spool but not what you are experiencing.

2 things I can think of.. 1:I suspect either the wastegate "flap" is not sealing the wastegate hole properly because of angle or the hole is off centre meanaing the wastegate "flap" is bypassed easier.

2: the journal bearings are bighting the shaft for some reason....start the car and let it idle, then look into the compressor intake and see whether the wheel spins....if it doesn't, let someone rev a bit and see if it starts spinning....that could mean that something is bent ot wrong not allowing free spooling....

I removed the air filter now, the wheel spins at idle....even spins after i have switched off the ignition. I also left the oil return off after I mounted the turbo to be sure oil gets to the shaft. all in order - i'm starting to think there is something wrong with this turbo....

arno wrote:

Draco wrote:

I am also of the opinion something is wrong with the wastegate, the exhaust housing is larger and would mean slightly later spool but not what you are experiencing.

2 things I can think of.. 1:I suspect either the wastegate "flap" is not sealing the wastegate hole properly because of angle or the hole is off centre meanaing the wastegate "flap" is bypassed easier.

2: the journal bearings are bighting the shaft for some reason....start the car and let it idle, then look into the compressor intake and see whether the wheel spins....if it doesn't, let someone rev a bit and see if it starts spinning....that could mean that something is bent ot wrong not allowing free spooling....

I removed the air filter now, the wheel spins at idle....even spins after i have switched off the ignition. I also left the oil return off after I mounted the turbo to be sure oil gets to the shaft. all in order - i'm starting to think there is something wrong with this turbo....

Then there can only be fault with the wastegate.....and the only way to check is to take off the turbo again...u say you are sure there are no boost leaks?

Draco wrote:

arno wrote:

Draco wrote:

I am also of the opinion something is wrong with the wastegate, the exhaust housing is larger and would mean slightly later spool but not what you are experiencing.

2 things I can think of.. 1:I suspect either the wastegate "flap" is not sealing the wastegate hole properly because of angle or the hole is off centre meanaing the wastegate "flap" is bypassed easier.

2: the journal bearings are bighting the shaft for some reason....start the car and let it idle, then look into the compressor intake and see whether the wheel spins....if it doesn't, let someone rev a bit and see if it starts spinning....that could mean that something is bent ot wrong not allowing free spooling....

I removed the air filter now, the wheel spins at idle....even spins after i have switched off the ignition. I also left the oil return off after I mounted the turbo to be sure oil gets to the shaft. all in order - i'm starting to think there is something wrong with this turbo....

Then there can only be fault with the wastegate.....and the only way to check is to take off the turbo again...u say you are sure there are no boost leaks?

sure there are no leaks, if I close my air intake the motor dies and the negative presure sticks. what if there is a design or manufacturing fault on the tubine wheel / compressor wheel....or are these turbos tested before packing?

Anything is possible...did you guys disassemble the turbo before you installed it....

Draco wrote:

Anything is possible...did you guys disassemble the turbo before you installed it....

nope, only rotated the bearing housing to match water and oil pipes.

Well let me start stripping again - I'm convinced that my exhaust housing/turbine is too big after checking everything. The guy from mr turbo says he had customers putting bigger turbo's on their CA18.....I'm not buying it.... can't believe it after what i'm experiencing. Thanks for all the advise guys.

I appreciate.

remove the feed to the actuator and jam the wastegate closed. Then take it for a drive, be careful though cause if it boosts like it should the only thing controlling it is your foot.

Daniel wrote:

remove the feed to the actuator and jam the wastegate closed. Then take it for a drive, be careful though cause if it boosts like it should the only thing controlling it is your foot.

I did the same thing when I tested my turbo since I thought mine was too small. I kept the throttle only lightly open until 5000rpm and then jammed the throttle fully open and the boost only got to like 0.4bar. The turbo was hence too small since at lower RPM I could get 0.8 and 1.0 bar.

I have also fitted one of these turbos you have on my SR now and it is a bit laggy. I spool from 3200 to 3500 and get full boost around 4000rpm. to help this I am going to be wrapping my exhaust mani, fitting a turbo blanket and gonna play with cam setups a bit.

I would imagine the turbo is big for the CA and you will probably need to do some work to help spool. I would also lock the wastegate closed with a suitable bracket and check where it spools from and what boost you can get. 😉

Oh and if it is really too big you goto get a TB28. just make sure you get one with the 47mm/48mm T3 wheel. Should be more than ample for the CA. BTW I have a TB28 which needs a recon which I am selling for R1500.
Should work lekker on CA.

phoenix s14 wrote:

Oh and if it is really too big you goto get a TB28. just make sure you get one with the 47mm/48mm T3 wheel. Should be more than ample for the CA. BTW I have a TB28 which needs a recon which I am selling for R1500.
Should work lekker on CA.

Hi Phoenix, I took the turbo to the guy that dyno's for me - he had one look at it and said it was too big! on my CA it will only start coming out of vacuum at around 4500rpm and started picking up boost at 5000 and 0.5bar at 7000rpm......ridiculous... felt like standard car without a turbo. I took it back to mr turbo and had to pay in another 1K for the tb28 because I drove the car once with the GT28... now I have to change my exhaust flange and shit - will yours fit the CA or is it like the one i purchased? also doesn't have water cooling. I think the SR produces more exhaust gasses to drive the turbine .

Hopefully I'll be using Phoenix's Slogan soon!!!

LOL! had to change my bolt pattern for the downpipe when I fitted the TB28 but changed it back again for the GT28... so it is different

Hi Arno. listen carefully , you might be upset but here goes !

stop buying " grey scrap " / copies / cheap chinese jobs from shops who sell these " fake Garret turbo`s "

IT WILL ALMOST ALWAYS COST YOU MORE MONEY & PAIN. I run an Original Garret GT2871R BALL BEARING TURBO on my CA18DET , purchased from Turbo Direct in Meyerton ( speak to Chris ) They are the official agents for Garret Turbos. The current rand/usd rate is good , so expect to pay approx. R 8 000 - 00 excl. vat .

Although i run a special equal length top mount manifold & lots of other special parts & HALTECH Management ( NOT Dictator !!!!!!!!!! ) , my GT2871R COMES ON SONG AT APPROX 3800 Rpm & boosts 1 . 3 bar tuned for pump gas 95 ul & making 440 Bhp @ the motor.

Once you have the correct hardware & software , tune with the best / people who know the game / reputable tuners ! ( i used Steve @ No Sweat Racing IN Meyerton )

GOOD LUCk & Regards ,
CHRISTO

VEREENIGING.