Turbo advice for a 3.0L turbo

[matty74]

I have a Garrett T04 ar .50 oil cooled turbo, that came of a 89 930 is this too big for a 3.0L turbo?

if so what mods can I do to it to make it suitable?

[matty74]

bump

can anyone tell me if this is too big or what would be most suitable for a 3.0L?

[the_preacher197]

Sorry, I hadn;t replied as usually people far more knowledgable than myself would be making suggestions.

Still, if I post something that's wrong that might provoke some more reponses for you!

The question of "too big" is not really relevant to the fact you have a 3.0 as it is more dependant on you're horsepower goals and other mods made to the vehicle.

If you're still running at 0.8 bar on CIS without an intercooler and looking for less than 400 fwhp than yes, I think a smaller turbo would be more suitable.

There are many variations on the T04 so I can;t really comment on the compressor side and total power potential. At best I can tell they have a 74mm hotside. This compares with a 68mm hotside for a GT35R (rated at 400-600 bhp) or 77mm for a GT40R (up to 700/800bhp).

That should give you an idea of where your turbo fits in dependant upon your horsepower goals ( can't provide much more help than that without the compressor specifications).

If you've got a fairly standard 3.0 I think a GT30R would be a better size (60mm turbine, 300-500 fwhp).

As for improving the spool if you want to stay with your current turbo, the way to do this is swap out the compressor housing for one with a smaller a/r. However, the smallest standard housing I can see is 0.48 which if your current housing is 0.5 isn't going to make much of a difference.

Therefore mods to improve the responsiveness will need to be mods made to the car such as headers or EFI etc.

It's a bit hard to answer the question without an idea as to how your car is currently setup and what you're trying to achieve.

[matty74]

thanks the_preacher197,

How can I tell what the hot side size is?

at the moment stock 930 3.0L this is what I was planning on doing for thr re-build

CIS
running B&B headers
964 or SC cams
keeping CR 6.5:1
1.0 Bar boost
Meth injection (NO IC) its a 73 wide body want to keep the old school look

Turbo compressor side is .50 a/r so if .48 is the smallest the no point changing it's current configuration

I was hoping for about 300 - 350 range

[the_preacher197]

I've got a 3.0 as well.

My build is as follows:

964 cams
7.5:1 95mm JE pistons
K27-7200 Turbo (0.8 bar)
Kokeln Intercooler
Headers
EFI

Results:



As you can see I don't hit full boost until 4000 rpm but I'm currently only using the Autronic to control fuelling and still running ignition curves off the distributor so there is definitely room for improvement but this should give you some idea as to what to expect.

[lite75]

A bump in compression really helps preboost if your using a large hot side.

[clutch-monkey]

382rwhp? bloody hell i'd love that figure..
trying to figure out what mine *should* be making as per the other thread

[the_preacher197]

Originally Posted by clutch-monkey

382rwhp? bloody hell i'd love that figure..
trying to figure out mine *should* be making as per the other thread

So would I!

Unfortunately the above graph was a flywheel estimate.

320HP at the wheels:

[KFoster]

Go to Forced Inductions

Look at turbo selection 101. It gives you some pointers on turbo sizing and why you should use compressor maps. Pretty good site. They are local to me and rebuilt my twin turbos for my Mustang. Proper sizing means a lot.

[RarlyL8]

Why is it boosting so late? With headers and EFI a 7200 should be at 0.8 bar by 2600RPM.

[the_preacher197]

Originally Posted by RarlyL8

Why is it boosting so late? With headers and EFI a 7200 should be at 0.8 bar by 2600RPM.

Not too sure and it's something that's been buggin me for a while. Could be a number of things:

1. It's a 3 litre not a 3.3
2. Cams are more agressive than stock
3. Still running standard distributor curve so no allowance for boost levels on timing.
4. Headers may not be as efficient as other options.
5. From the service records it appears the turbo is the best part of 20 years old so may be past its best.

More than likely it's a combination of all 5.

Do you have any graphs showing the response of a 7200? I always hear about how they reach 1.0 Bar by 2600 rpm but can't recall seeing any dyno charts, especially for a 3.0.

I'm hoping to find some time/money later in the year to address the problem. New house & baby over the last year has dropped the 930 down the priority list.

In the meantime, here's my 3.0 against a lightly modded 3.3 (just 1.0 Bar spring from memory):



Farily happy with the top end on mine but it would be nice to fill in the below 4000 rpm part of the graph a bit.

[Adandos]

There are many T04's ranging from 358hp @ 26psi to 650hp @ 35psi

So depending on which turbo you have in your possession, it's either good or too large for what you're using ...

You should check out our turbo calculator sizing guide and our comprehensive horsepower calculator

We have over 110 turbos in our database and by knowing more details about your engine (besides its displacement, like it's VE and specific output) we'd be able to give you a more for sure answer.