RWD Pete

Im now running around 450 bhp on my 38 but i need more power, i have considered a t4 but surely it will be less responsive. Im happy enough with the spool up time on my 38 but i want to break the 500 bhp barrier.

So whats the pro's and cons of gt30 and which one would be best

ta

Lo@der

iTrader: (8)

I was told by a few people when I was looking at a t38 that there isn't much difference in lag between t34 and t4. Nms told me there was no point in having a turbo with t4 lag that doesn't flow t4 amounts of air.
I'm not havin a pop at your 38, just saying a t4 might be ok fore you.

Turbo Zetec

iTrader: (1)

gt3076r is the usual choice

RWD Pete

so a t4 is basically the same response a my 38 with morewind?

rapidcossie

roller t4 is as responsive as any GT30 but a good bit more powerful

Lo@der

iTrader: (8)

Yes thats what I was told. Get CR turbos to do you a rollerbearing T4, i think they quoted 1k., the lag should be reduced by 400-500 rpm. I think Mike R runs one on his escort.

RWD Pete

Roller t4 is prob what i need, is it a direct swap for my tt t38 and is it internally gated

Lo@der

iTrader: (8)

yep.

RWD Pete

Right i'll call them in the morning along with TT and aet

cheers

Chip

iTrader: (3)

Really?

I guess garrett spent 10 years in development and decided to release something worse than what they had to start with then, seems a strange move for an inteligent bunch of lads

3i_gaz

i've been in a big power saph on a roller bearing T4, and AJC's GT30 monte, and can honestly say they feel like 2 TOTALLY different cars.

obviously they are ones a saph and ones an escos before some smart arse says it lol

the T4 even roller bearing was still very laggy i thought where as the GT30 on andys escos, the power comes in so smooth and is less kick you up the arse. but fook me its still as quick as a T4 car.

must be more driveable too i would think.

NEIL A

iTrader: (6)

I have just switched from a UT T38 to a CR T4, was only running low boost as i was just finnishing running in but it was making posative pressure at the same point and felt smoother on boost.

Kelv

iTrader: (4)

Gaz, Andy's is the smaller housed GT30, still makes nice power figures and pulls like a train but has the benefit of spooling up with the characteristics of a T34.

so a little hard to compare against a T4.

JonnyBravo

The only car I've been in with a roller bearing T4 was Mike R's and I wouldn't call it laggy, that had awesome power from low down all the way through the rev range. That is obviously a very well specced engine but also very impressive.

Any turbo will be shit if its fitted to a wrongly specced engine, T38/T4's don't work particulary well on standardish engines which I think is why people start to slate them.

One reason I didn't choose to go for a Gt30 was in rwd I can only see me struggling like crazy to get grip, When a GT Turbo starts making boost it makes the rest very quickly in comparsion to a T38/T4 for example, this is only going to cause massive traction issues which I think any 400+hp rwd car is going to have anyway so I'd rather not make it any worse. (That MY opinion on it anyway)

Dunccoss

i was told that the turbo on mikes car didnt make boost any sooner than a normal t4 ? and it was the fact that he has a few more cc's that makes the difference ? i could be wrong but it did come from a very very good source and that 9is why i am going gt30 with a 63

Ryan

james, as you've said, its all done to the engine more than the turbo.

as you found out with my t34 setup even running low boost and no spike.

the is no replacement for displacement hence mikes is very responsive, but also helps with the silly inlet and matched engine by harvey.

personally i dont think there are many turbo's that are laggy, obviously jumping from a t3 to a t4 you'll see a massive difference, but i tihnk alot of it is down to driving style, and this has to be adapted to suit the large turbo's. so gear's have to be held for longer and sometime a change down is needed rather than just going for WOT.

i've been in plenty of non roller bearing t4's and there is a massive difference purely down to driving stlye which affects the way the turbo is kept in its threshold.

JonnyBravo

I still can't believe how responsive your engine is compared to my mates ! properly weird that is, I'm guessing his engine is one of the 6.8:1 era of engines lol

I don't actually see there being any issues with just having a properly specced rs500 engine, nobody will catch you if you can drive it, I've been out with a proper driver in a proper 500+hp T4'd car and there is no way you need anymore power than that unless your into drag racing or top speed, best experience of my life being shown what a properly powerful car can really do

Ryan

as you've said, i went out in martin j's old rs500 with 500 touring spec engine, and its probably the quickest RWD car i've been in.

still managed to do a 12.0 with the old touring setup.

but most people go more power to impress people down the pub or on here

gibbo frst

iTrader: (2)

is it a big difference between an rs500 t4 ant the turbo technics t38.. people say it has a t4 sized front housing and from what i can see both have .63 exhaust housings..?
most of the tuners i rang to discuss mapping the tt t38 didnot rate this unit and prefered the other versions...?

NEIL A

iTrader: (6)

One of the quickest cosworths i have ever seen was a old school touring car T4 type engine, stupidly fast on the road and quickers than most of the new GT turbo'd cars on the strip. As Jonny Bravo says its all down to adapting the driving style to make the most of it.

JonnyBravo

lets not go there

JonnyBravo

I thought they had .82 housings didn't they ?

There is nothing wrong with a TT T38, I didn't pay rrp on mine which made it a very cheap new turbo, fitted to a sensibly specced engine it will deliver what I want, infact I can guarantee it will deliver more than I'll need as I'm not Lewis Hamilton.

gibbo frst

iTrader: (2)

im more than happy with my tt t38 and the service from turbo technics is excellent in my experience .. think i saw a t4 for sale and it said it had .63 exhaust housing i just thought they were all the same ... always wondered what the difference was...

JonnyBravo

I'm not 100% sure what exhaust housing they had, I just remember hearing .82 mentioned at some point in a conversation about them.

foreigneRS

.63 is just a ratio.

JonnyBravo

this is true I'll leave you to explain the rest Nick

rapidcossie

Test, dont guess.........

thats what we have done with my car and the results speak for themselves, my car is WAY more responsive than any similar power car AVA has seen on their rollers.

Keep an eye out for another revsion of the T4 on my car very shortly.

RWD Pete

Not wating ore power for anyone else but me i love it. My turbo isawesome and the ony reason i anna change is for more power but i dont want moreaghence going for a roler bearing setup.Seems to be aot ofdifferent vies on both t4 and gt30

RWD Pete

Does this mean your selling the one you have

cossie4i+

iTrader: (15)

You pissed Pete ???

Thats as bad as Dojjs spelling

Steve.

Gordon1

GT3076R for me

3i_gaz

ahh right, i dont know the spec of the turbo to be honest mate.

it was a total differnt sort of fast compared to my mates T4'd saphy

rapidcossie

The exact one I have wont be for sale but turbos exactly the same are available of the shelf

montecos400

Ive just gone from a t34.63 to a CR turbo's roller t38.

Lag has been reduced massively and no more big hit of boost at 3.5 - 4k.

The t38 is really progressive and smooth all the way to 7.5k.

NEIL A

iTrader: (6)

I got mine within the week from CR, there not cheap but hopefully it will do the buisness.

R5FORD

iTrader: (1)

not everyone has money and time to invest in testing turbos like ava have done with you Euan. and theres no point going by your spec turbo when there engine spec may be completly diffrent.

rapidcossie

You dont need to go and spend time and money as we have done it with the backing of CR turbos, they now sell the turbos AVA specced for my car.

The research has been backed up with actual test data posted on here for everyone to see and a few high speed runs to prove the power that car has.

IMO it will suits any other normalish cossie as my engine is low comp with old touring car style mods, very similar to alot of others on here.

R5FORD

iTrader: (1)

ahhh ok i get you mate..

wasnt a dig at you or anything

rapidcossie

Isnt it already doing the buisness judging by early results?

rapidcossie

I didnt take it as a dig mate

The T4 I have is arguably stronger, more powerful and give these results with less backpressure than the equivelant GT style turbo.