What turbo and wastegate have I got??? Rebuildable?

[timbosaurus]

OK, so I recently picked up a cheap old turbo and wastegate on a very rough 18R manifold. The turbo most certainly needs a rebuild (it's useless as-is), and in keeping witrh the theme of budget I would like to try my hand at replacing the bearings and seals myself.

The axial/thrust play is minimal, but the radial play is disasterous!!! The compressor wheel can (and has) touched the housing.

I'm wondering if anyone can help me out ID'ing the turbo, and any info on cheap places to buy rebuild kits would be really appreciated I'll take some pics and measure some of the sizes tonight, but for now I only have words

Inlet

The front of the compressor housing has no obvious markings on it. There is a small raised rectangle cast into it, with "0282" stamped on it, but this looks more like a batch number than a model number. On the back face of the comp housing "AIRESEARCH" is cast on it. Smallish size... maybe T25ish?

Exhaust

The exhaust housing is quite sizeable. It has no internal gate and IIRC the A/R is stamped 0.64 or 0.63 (will confirm tonight). The stud pattern is a 4 bolt rectangle, I will measure it tonight as well. Largeish size, maybe T3?

Wastegate

The gate looks beefy and has a blue build plate indicating it is a 38mm gate manufactured by "NormalAir Garrett". I'm guessing a regular 38mm garrett job, but looks big and old... kinda like an old truck one

When I bought all this the guy said it was a T28 from an early scorpion or something, but I took no notice at the time as he sounded like he was just making shit up. He may or may not be correct, but I suspect the later.

I just thought I would post up now in case anyone recognises such a beast... I know it's unlikely without photos though, so they will come soon.

Cheers,
Timbo

[BeRad]

i had the same gate, and it did a perfect job, dont get rid of that one, put it down low or give it a lick of paint.

[timbosaurus]

Thanks Mate!

I just remembered that it had also something written on it like "5psi actuation" (cant remember exacty though).

This sounded pretty low, so i'm just curious how controllable it would be using a valve to bleed off 10psi? Or if 15psi is the aim, is it better just to get a stronger spring?

Cheers,
Timbo

[The Real Roadrunner]

it should be a 9psi spring in it.
the turbo sounds like an old sigma one. it should have a splitpulse rear t4 pattern on it and be a vband clamp rear.
the shaft will probably need a grind and new undersize bearings fitted (not a diy job) the a proper high speed balance.
front cover shoult be either .5-.6ar with a 54mm minor 71mm major front wheel.
if you upgrade the rear wheel to a sierra one these things can pump 250+rwkw but i would suggest simply backcutting the factory one so it doesnt choke everything up if you go over 14psi.
cheers
linden

[timbosaurus]

Wow, thanks Linden!

The gate definately has something about 5psi written on the plate, and it's not necessarily from the same car as the turbo. What makes you say 9psi? is that a standard garrett pressure, or is that the spring that the sigma's had?

Yup, the front and rear both run v-band clamps, and the carby that was on it was a "zenith" SU. I've just had a search around at some piccies of Sigma's and I think you might be spot-on. Carby and turbo look the same

Bugger about the regrind... was hoping that the shaft didn't need grinding, but I think you are right I'll pull it apart and do some measurements to get an idea anyways.

So you think if I get the turbo rebuilt with standard wheels it should suit a stock 18R till it starts blowing ring landings

[BeRad]

I dont remember any spring rate being on my gate, but it ran a rock solid 10psi with no controller, pluged into the ebc and it held perfectly whatever i would set it to.

[timbosaurus]

Thanks guys!

OK, consensus is that it's an old Garrett turbo and Zenith SU carby from a GH sigma. Not sure whether the wastegate is from there as well.



details pulled from a sigmalovers website says...

"The engine was the 2.0 litre Astron with a Garrett Air Research T3 turbocharger and Zenith CD carburettor. Compression was reduced to 7.8:1 with boost running at 10lb. This increased power from 64.4kW @ 5200rpm to 116.0kW @ 5200rpm."

Should be a fun project to put it on an old 8.0:1 comp 18R

I've no idea what the wastegate is from, I wouldn't imagine that it is sigma gear, but it could be.

I've added photos for those interested

Turbo


comp housing


Exhaust housing


overall size


Wastgate - BeRad, is this the same as yours?


label - this would imply the gate is set to 5psi right?



Once again, thanks for all your help guys

Timbo

[Norbie]

Are you sure you want to waste time and money on an old piece of junk like that? Even once rebuilt it won't be very good. Turbos from VG20's and RB20's can be picked up cheap as chips in good working order and they're way better than that old thing!

[timbosaurus]

Nah, i'm not sure.

The situation is that it's sitting on a functional (but ugly) manifold, and is complete with turbo, carby and gate.

I've never had a retro suck through carbie setup, and feel like mucking around with it to see how bad they really are

If I could find a usable turbo that'll bolt straight onto the manifold and carby, and be cheaper than rebuilding this one, then i'd be happy to go with that.

Don't worry, I wouldn't be doing it as a performance excercise... I still have a late model turbo halfcut for that. I guess I just enjoy the challenge of getting things running. If I can pass it onto someone who desires such retro coolness after its working well, then it's even better

I know exactly where your coming from though Norbie.

[fixeruperer]

yeh that wastegate is from sigma setup.
suck threw isnt that bad it just doesnt always start on few first turns of key, the fuel mixed with the air thru the turbo can get pretty dam cold too so thats a plus.
one of my mates tryed playin with his sigma setup it overboosted, valve bounced nocked 2 collets off and droped a valve boy was that messy half the valve went thru piston the other half found a new home inside the combustion chamber.

[The Real Roadrunner]

Are you sure you want to waste time and money on an old piece of junk like that? Even once rebuilt it won't be very good. Turbos from VG20's and RB20's can be picked up cheap as chips in good working order and they're way better than that old thing!

you may want to retract that stament as that same piece of junk is what was on my 3sgte and it put out a solid 240rwkw @18psi all day everday.
we took it up to 22psi and it made 267rwkw but was causing valve float so we backed it off.
the only diff between mine and this was the rear wheel was changed to a stage3 sierra wheel.
BTW the car smoked 5th gear @140kph+ so the power was deffinately there.
cheers
linden

[The Real Roadrunner]

same gate as mine but mine had a 9psi spring in it so they must have changed at some point and yes the sigma's came with them factory.
cheers
linden

[timbosaurus]

Thanks Mate! awesome info!!!

Just found some more sigma info, and yes, it agrees. This is standard gate.

However, standard size was 32mm... so I think I just read the size incorrectly (very incovenient scratch on the label) and I have seen/read all sorts of different pressures (6,8,9,10psi) so either ppl are not very observant, or they made several different versions.

That 3SGTE sounds crazy! I'd be absolutely stoked with half that power