T04Z Or Gt42 Roller Turbo For Street

[ab_futura]

I have a choice of either one. How do these two turbo's compare? What are there power ratings and what are the diferences in spool time on a manual ba xr6 turbo? I'm going to be happy with between 400 and 450rwkw but I want the car to be as responsive as possible and make boost sooner rather than later. I don't really care about dyno comps or drag racing, but it has to be fun on the street and the tack for events like powercruise. I'm thinking the T04z but would like to get some opinions. Cheers.

[bcl]

GT42 is much laggier, but a lot more top end. Power output depends on spec of turbo and wheels, but say >500. Not much happens under 4000rpm.

If you only want 400 to 450 then T04z would be better.

If you go the GT42 I'd definitely recommend the 4.10 diff for better drivability.

Brian

[01txr]

Go To4z

With good set up you will turn quality tyres in 3rd with under 20psi as well return under 9l per 100k Eco and I know with mine it's making boost from as low as 1100rpm at 60-70kph.

Also they don't like stock BA rods.

I run a mates BF F6 that runs modifed GT45 on private driveway, mine just boosts and puts 1-2 car lengths on him before his spools up and it's all over as cant close the gap quick enough, I was only running soft 12psi tune no idea on actual power as tuned myself not dyno'd. Budget build by myself.

He was running 600rwhp pump fuel tune by very respectable shop, lots of dollars.

Even though he was making more power it wasn't suited as a street friendly setup.

If he slipped the clutch to get it spooling quicker he had huge wheel spin issues.

What your wanting I think you'll love the to4z.

It's great performer and I have heard a few auto's running 9's with them.

Make sure you have decent tyres, clutch and fuel setup, watch out on BA rods and cv's and don't bother with 4spd auto or 5spd manual it will destroy them.

[icer]

or instead of spending 5k on a t04z setup, you can modify the gt35/40 with t04z wheel/internals etc + external gate like you would the gt42. you can use same standard t3 manifold too. Set you back like 1500$ and good for +450~ rwkw.

[RIP_HSV]

I just sold a 3540 with .70 front cover and T04 internals was capable of making 424 rwkw's in my auto so would possibly make 450ish with a manual, good set up for street cost me $2400 including custom intake and fitting etc and like *Beep* said fits up to stock manifold, currently upgrading to a 4094 set up with 6boost low mount, custom dump pipe and air intake to suit.... also good for the street but expensive in comparison.

[01txr]

Me personally would not waste money on the factory turbo as when I removed

Mine when I upgraded to the To4z, I found numerous cracks in the factory exhaust housing.

It's a known problem with them In the BA-BF series.

They crack around the wastegate valve hole and worst from the bolt holes for the cartridge which cause the housing to cartridge bolts to loosen off.

As well not to mention the limiting size with the gate making boost control not so controlled.

I still have my exhaust housing and can take photos to show how bad they can crack.

I bought my TO4z on recommendations from numerous shops of them being the best suited street turbo for a manual T.

If you where to do up a factory turbo with new wheels I would at least get a decent exhaust housing with external gate flange welded on like what ETM offered sometime back.

Also use the FG housing if you want to stay with the internal gate as by memory they had a larger gate standard and the housing material was a upgrade to fix the cracking problems.

Yes the TO4z setup will cost more then just molding the factory turbo but you end up with a better manifold, improved boost control with ext gate, higher quality turbo.

By time you modify the factory turbo its not that cheaper, you can sell of all the factory turbo setup to offset the costs for the TO4z or if wanting numbers up high a GT42 or larger as Bcl stated.

[bcl]

Another perspective is that it’s not just a matter of putting a bigger turbo on.

Once you go over 500rwkw your costs will increase substantially to do it properly and with increased reliability.

You may need to budget for bigger air filter, bigger injectors, 2 fuel pumps instead of 1 (or much bigger single), bigger intercooler piping, better exhaust if back pressure become an issue, maybe stronger internals, better brakes, suspension upgrade …..

My BF F6 has a modified factory turbo with t04z internals, and it’s very quick for the street, and I’m quite happy with that when used with a modified quick shifting ZF. A very good compromise without going over the top.

You talk about fun. There are 2 sides to fun for me.

1. a smaller responsive turbo and quick spooling turbo for good drivability

2. the fun associated with massive torque, and that’s usually 4th gear acceleration in a big powered manual

Both are very different.

Many times in the past I’ve gone back from larger turbos to smaller turbos, because overall I think a more responsive turbo is more fun and more usable.

Always a matter of opinion.

Brian

[qik1]

Lag can be attributed to more than turbo size. If you do a half arsed job of it the results can be sub par. It's all about efficency & the systems that support it, if you have the appropriate size intake, piping, I/c, intake plenum & of cause exhaust manifold it can reduce the effects of having a large turbo. With a gt4202 & std stall on a zf6spd im making boost by app 1500-1700rpm and can leave the line at about 8psi (havent tried for anymore).

Of coarse its not quite as good as a stock turbo but is noway frustrating & with my smallest street tune which is the best part of 600hp I have to really try to get it torch the tyres. This does of coarse come down to the way its tuned in which I can't take any credit. I would consider it to be a very streetable setup & very quick, I'd dare say theres not alot out there for me to worry about if I was into the whole street racing thing.

On the other hand I did spend alot of money & spent alot of time to have it this way & havent been in another car with the same turbo so I can really only speak from my own experience. Im sure with either setup you'll find what ya looking for. As Brian said once you do start pushing those bigger numbers which the 42 is more than capable of theres alot more to consider than just bolting a turbo on.

Good luck bud.

Edited 28/01/11 12:23 AM by qik1

[Turbo6FG]

So for a car that's nice & responsive for the street & will run easy 10s at the strip a to4z would be the best option out there?

[RIP_HSV]

or a 3540 with .7 cover and T04 internals if you dont want to spend big $$$ on manifold dump pipe and intake mod's to suit