Hi all thinking of a turbo change for my car in the future and was wondering how the gt30 performs? The car currently runs a t38 which is good but im wondering how a gt30 would compare as ive heard good things. Cheers

 

Thinking of going this way, too. Heard about the good response.
The output depends on how big the housing is, but with a .82 one you will see just over 500 Hp I guess.

Cheers

 

Im thinking the right spec one would most likely spool quicker and hold the power longer aswell as making a bit more power but be great to hear some opinions from people using/have used them.

 

Make of engine/spec of turbo and engine would help you on your question.

Mark

 

Yes should of wrote that really! Its a cosworth yb, long studded 200 block, ported head, bd14 inlet cam, std exhaust cam, a.s inlet, t38 turbo- unsure of the spec but its peaking at 34psi, air injectors, mapped by nms on level 8 ecu i think. It goes very well but its fairly laggy, no boost till 4k rpm which is ok but im sure it could be better with a more modern turbo aswell as possible a cam change if the bd 14 is unsuitable for whichever turbo i went for. Cheers

 

No boost at all till 4000rpm on standard exhaust cam sounds a bit lazy to me.

I would think changing to a Gt30 and getting it mapped right you could bring that down circa 800-1000rpm.

I have positive boost at about 2500rpm and full boost by 3800ish and that's with BD16in and BD14ex.

 

What turbo are you using mate? When i say no boost till 4k rpm i mean that it comes in hard at around 4

 

Gt3076 .82 cams as stated on a really nice NMS ported head running siemens 83lb blacks, 4x4ex mani and 2wd in mani.

 

34psi on a t38?

 

The gt30 should be better with the correct spec than a t38 for spool up but the fit a gt30 and all the bits needed to get it to fit you may aswell spend a bit more and go twin scroll Borg Warner turbo, as this is the way forward, which is what iv done.

 

id say it hard for most cosworth drivers to put the money into one of the new b/w turbos,
ends up a lot of cash by the time you ve a twin scroll manifold , remap etc,
no doubt they seem to be unreal ,
just hard to justifie on a car that does maybe 500/1000 mile a year !
or maybe that's just me lol

 

It doesn't work out much more than fitting a gt30, if u buy a new gt30 with all the correct parts to fit it to a yb it works out around £2k if going external wastegate, for a little more, £2200, u can get a twin scroll tubular manifold, Borg Warner sx200 external wastegate, this is what it's just cost me. The engine will have to be re mapped if either a gt or Borg Warner is fitted.

 

Is it the GT turbos that suffer from the oil pressure problem and need a reducer or do I need my head testing?

 

No boost until 4k!!! Damn.

I had over 2 bar at 4k on my gt30 setup.

 

with the correct bore size feed line used and a yb making what about 60 psi oil pressure roughly it shouldn't really be an issue imo.

all you need to ensure is that at working temperature the turbo feed sees no more than about 45 psi, I think a lot of the issues come when to big a bore of feed line is used feeding to much volume of oil per second to the turbo which then increases pressure above 45 psi and the seals can leak.

 

Dan- its sposed to be 34 yes, i havent dared to take my eyes off the road to look at the boost gauge yet!
So is a gt30 likely to come on hard about 3-3.5k then? Does the power hold on well higher up the revs? Would i need a fancy manifold and external wastegate setup or standard manifold and internal gate ok?

 

Steve,

click on the link in my sig. Its a massive thread from a few years back when myself and Mark Shead from MAD built my GT30 spec. Will give you all the answers mate

 

How good a gt turbo is on a yb largely depends on who spec'ed and maps your engine lol. I'd say mine was very responsive and very very fast as a road car with my 3076 with a .82 wastegate. But I've just resently been informed by the guy who I sold my turbo too that his tuner tells him it's not spec'ed right for a yb and is a nissan turbo and will not make any boost below 4500rpm! So I'd chat to who will map it for you

 

Best thing Steve go see Harvey let him see what you've got then he can give you a few ideas to which way you wanna go,won't be cheap tho lol as you know you'll end up with a diff and beam while you are there

 

Cheers cossierich, read your whole thread and some great info, thanks. Sounds like you had some real bad luck with it.
Dan its booked in with harvey next monday to have a checkover and make sure fueling is safe and nothing else silly is about to go wrong, and also discuss different spec for the future. I know it will get fairly expensive and not really in a hurry to do anything tbh, will just do bits as i feel like it and can afford to

 

steve i can show you some comparrison graphs when you pop down of different turbos and spec if it helps

(hope that dosnt break rules mods??)

 

Spec'ed for a nissan and yep it is funny lol as it went fooking well on my car!

 

Yes that would be great jim, cheers

 

I really like my GT3076 worked well on my last motor, to some it may be old hat now with more modern equipment available but it's a decent fast road unit - mines the .82 back end and internal gate

 

I had a gt30/71 with a .82 housing coupled with a few other bits made a proper fast road car as tech moves on you getter better options but the GT's are still good turbos imo

Luciano

 

I ran a gt3071 on a 0.63 hosting on a 2.1zetec, it was cammed with mild porting. Spooled up to 2 bar by 3400rpm would see boost building just over 2krpm. Decent turbo, gtx would be my choice next though, for a bit more cash then an efr would be the ultimate choice though.

 

Gtx are no good ime. The gt standard series are better.

 

Why would they downgrade a Turbo Jimbo you may have not made it work i can believe but the gtx spooled exactly the same as a gt but made more Power at the Topend. I know cos all i did was change from a gt to a gtx so know what you say is not a true statement.

 

my 3800cc v6 runs 2 billet custom wheeled gt30 cores so the curve should still be similar to a yb as ive only got 1900cc driving each turbo, and power/torque figure can be cut in half effectively

on a low 1.6 bar of boost on pump fuel alone, full boost around 3500 rpm




im 99% sure my vr38 isn't twin scroll either, its on stock ported manifolds which I think are just like log manifolds


they are super responsive, in a different league to an old t series turbo I have no doubt.

im sure on a correctly specced yb head and turbine housing you would be in strong boost by 3000 rpm, full boost before 4000 rpm.


the biggest thing I noticed with any roller bearing turbo like the gt40 I had on an rb26 was it made a little boost down low only 3 or 4 psi but it all helps keep the motor alive, my old saph had a t4 and it was awesome but it literally had no boost at all below 3k rpm it was proper lethargic at best


the other option is can you get a custom roller bearing core and billet wheels for your t38 to drag it into the 21st century and keep all the fitment aspect the same ?

 

Your Gtx 42 was good and the 35 works but the gtx 30 versions both types are not as good as the normal version.

Mark

 

Rod Ive seen a fair number of people transitioning to gtx now and all coming back with a hike in power however, all at the expense of a couple hundred rpm in threshold. Any ideas why?
I just put it down to/excepted that the geometry needed for the billet wheel to flow more required more energy to be put in from the same turbine as used on the non gtx?
Which then got me to thinking unless you restricted the a certain frame turbo and/or absolutely need the extra flow the gt would be a better choice?

 

Rod, ask Mark his opinion on custom turbos or mismatched turbos.
The gtx series was just a billet wheel put onto the same turbo so they have increased the flow rate comp wheel side with nothing to compensate on the rear, or atleast this is my understanding of the two gt30s and gt35 varients and ime they dont work. (Hence the mismatched turbo comment i know mark dosn't like )
I will only give people information i have seen with my own eyes, if they dont wish to ask me to delve deeper on my testing (as it may suit them) and go ahead and try one anyway then fair enough.


Also if you look at my reply more closely, you will find it was to a previous comment mentioning the gt30 version.

P.S. My statement was correct as it was found in my experience, thanks.