As title really.

They all of similar size, but GTs far more modern, and produce a bit more power for their size it seems (more efficient), but have bigger a/r exhaust housings too.

Legend has it that they spool up much faster too, even though the ex housing a/r's are bigger.

But has anyone gone from a T3 or similar pissy lil turbo to a GT25/28 and seen if there any noticable difference, esp in responce, what rpm the boost threshhold beghins

 

I'd be very interested to know. Christian's car has a GT on it, used to have a 0.48 t3 - keep meaning to ask about that. The power output thing is pretty much unproven though, and as of yet - i don't beleive the hype...

Rick

 

What got me thinking is over the last few days ive been driving a brand new Mk5 Golf GTI 2litre Turbo around a lot, and frankly, its fucking awesome.

I love the handling, but the engine is feckin superb.

Even at 2000rpm your at full boost the nanosecond you boot it, and you fookin flying.
A remap gets you 250bhp too, so the turbo is far from its limits.

Cant see that coming from a T3 capable of similar power somehow...

 

No, i know what u mean. It's a 2 litre turbo, so should behave like a cossie lump. What turbo does it actually use?

 

Actually - have you driven a small turbo escos? As they have NO lag either.

 

Well ive driven a Focus RS and this Golf way better than that, but never driven a small Turbo EscCos.

No idea what turbo it uses.

Thinking about it, Small Turbo EscCos turbos are good for approx same power as a 2wd cossie T3 isnt it? But far less laggy isnt it?

 

it is far less laggy yea, the t28 is a more modern turbo i guess.

The FRS turbo will push out over 300brake, so will be bit bigger methinks.

 

Indeed, so id say the GT25R/28R would be a step up again?

People have fits about how the 28RS is totally lag free on a 2litre and thats proven to give well over 300, so god knows what 25/28s are like...

 

Well, im thinking a GT isn't THAT much of an improvement over the t28.

I'd love to try a GT28, think it would be mint for my steel cvh. How much can u get em for?

 

my std t3 seems fine. hits full boost by 2500, but would like to try a mk5 golf GTI.

 

thinking that rick, but any real idea? i havent!

GT28Rs go for about 900dollars new in the USA, whats that, 500quid?

 

i bought my GT28R for about Ł400 but got hit for Ł100 on tax.

Apex Performance sell them fro about Ł550 in this country, good price.

on my 1.8 i am seeing boost from low down < 2000rpm probably (not really looked). i hit full boost by 3,500rpm (give or take a few hundred). i'm running 18psi and should be at about 300bhp.

one thing though, the GT28R doesn't seem to want to hold to the 7,200rpm redline and there are a few people with different specs who run one on a CA18DET, all of us seem to have 16psi by the redline. (some people have big FMIC's, electronic boost control, etc - the one common factor is Mongoose exhausts, maybe they are restricting us all.)

i think the GT28RS is probably a better option than the R (the smaller RS - 350bhp one)

 

would be interesting to see this also...

by any chance could one of u recommend a turbo suitable for 350hp (give or take a little....might add nos) on a 2.1 16v zetec engine? everyone seems to be using T34's...but unsure of the power of these engines

bassboy

 

Is it really that slow in building boost? I mean it starts low at 2000rpm but then what?

I get 18 psi at 3000rpm and full 24-25psi at 3250rpm with a T34.

Btw, Saab and Volvo had these lagfree engines were you get close to full torque from 1800rpm for years.

 

Andreas, if my T34 picks up as well as yours does on my zetec turbo i will be well happy

 

my car is quite linear as it comes on boost. its not like some cars where it's nothing, nothing then full boost and it pushes you back. mine builds slowly and steadily, it gathers steam at about 10psi and the remaining 8psi builds up a bit quicker.

you must remember mine is only 1800cc. i also test the boost in 2nd gear. if i was in 4th and 5th i can see 18psi by about 3k.

i think the fact that my engine has a jap 8 port head that switches from 8v to 16v when it comes on boost makes spooling characteristics different.

 

please explain ???

 

also please explain
why test boost when its not loaded

 

On my 200 with a S14 T28 I get full boost about 3k dependant on gear used which is anything upto 1.4 bar however it only spikes this briefly.
I love the T28 tbh as it makes the car so drivable and like Escy mine is also a 1.8 CA18DET, only thing is it feels like its runs out of puff about 6500rpm in the higher gears.

 

i've gone from t34 0.63 exhaust to gt25/40r 0.64 and there's big difference in spool up time, this is on 2.1 zvh.
My t34 started spooling up at 3200rpm where as the gt series came on boost at 2500rpm, also i ran 24psi on the t34 on greens and i still had loads of fuel left in my map but with the gt turbo injectors maxed out at 19psi power differential i gained 40bhp over the t34 but gt turbo runs with tubular manifold. t34 small compared to the gt25/40r

 

the theory is you get nice driveability and better torque when its 8v with better top end power when it switchs to 16v.

the inlet manifold and head has 8 ports rather than 4. 4 of these are blocked with the injectors in the other 4. as boost increase's they open up. they are connected to the vaccum/boost pipes.