iain atkins

Hello

I have a MY97 Uk turbo with de-cat, induction kit, ported exhaust manifold and intercooler pipework and intercooler splitter.

I have noticed a couple of times a burning oil smell from the exhaust and have had it diagnosed as worn turbo seals. I bought the car at 52,000 miles and although i have warmed up and cooled down i have no idea if the previous owner did this (is was a company car for the first year of it's life ).

I had the short block changed when i bought the car (piston slap) and had no. 4 piston replaced recently because of slap. The car is now run on Motul 300v 15w50.

I want to run the standard ECU but have a stronger turbo fitted which will run cooler but not be any laggier. I was thinking of a VF30 or VF24

Fueling is on the rich side at the moment.

Any ideas pls

Cheers



Iain

PS. sorry for the long post

[Edited by iain atkins - 3/21/2002 10:04:29 AM]

WREXY

I'm not the best person knowledge wise to be replying here, however I can tell you that the VF30 will be laggy, it's, shall we say size, is in between the VF22 and the VF23.

The least laggy turbo's are the VF24, VF28, and VF29. These three turbos are the same thing basically, but differ in that the VF 28 and VF29 have a different location for the pressure hose on the wastegate actuator.

One of these three will give you the least lag. I think these three turbos spool up slightly quicker than the TD04.

Cheers,

Wrexy.

SecretAgentMan

IMHO a 24 or a 23 would be perfect, problem is that even the smaller 24 flows a fair bit more (had to put in quite a bit more of fuel to get the needed AFR), I would monitor AFR very closely if running it on a stock ECU - but as U say, it runs pig rich stock on top, but with some breathing mods a few cars have been known to run lean in the middle.

Maybe an ECUTEK remap as well?



/J

Adam M

TD04 spools much quicker than a vf24 type turbo.

wrexy, I like the way you put its size between the vf 22 and vf23, which are identical in size in every way, btu I know what you mean!

I would go with the turbo I just sold. It was a funny hybrid with a p18 exhaust housing, and an enlarged waste gate button to flow more air up the top.

It made 344bhp at 1.25 bar on a friends car (UK) but with l;ink, and hks fmic. Yet still produces a bar by 3000 rpm.

Let me know if you want to source one, I may still know of one for sale.

WREXY

Adam,

Glad you understood what I meant. I suppose better wording would have been, it is a compromise between the VF22 and VF23.

Cheers,

Wrexy.

Stelios

Adam M u have mail

JamesS

Hi there,

Just put a VF30 on a 00MY UK car. Got the usual other extra`s..........

I was running the TD04 at 1.2bar using the Apexi AVC-R, boost at 6500rpm around 1.1 - 1.0 bar. Getting 1.2 Bar at about 2400 - 2600 in 5th gear from a constant 2200rpm cruise.

Fitted the VF30 last weekend......I`m running 1.0Bar at the mo, till I go to PS tomorrow......

Anyway running 1.0bar on the VF30 I`ve lost about 500 - 700rpm in terms of boost threshold. Part throttle performance is virtually identicle. I hit 1 bar by about 2900 - 3100 and this remains rock solid until 7000.

The midrange grunt feels about the same as the TD04, at 5000rpm the performance difference is surprising, at 6000 it kicks and flies to the redline. The TD04 was harsh and starting to tail off at 5000 - 5500....

So the VF30 at a lower boost setting (1.0 Vs 1.2 bar) is as quick in the midrange and significantly, that was SIGNIFICANTLY, faster above 5000rpm......

I do miss the huge, virtually instant hit from the TD04, at 2400, but it`s over relatively quickly, the VF30 gives more of an Evo / STi feel (go figure as its the new Sti turbo!!) without sacrificing too much low end......
Mapping to 1.35bar tomorrow...muuuummmmmmmm.

RobJenks

If you are proposing to go for a VF then a FMIC should also be considered if the new turbo is to be properly optimised.
I have a VF22 / Hyperflow FMIC and it is quite an awesome combination - especially running 1.4 boost!

BugEyed

James

Mmmmmm - sounds fantastic. Jealousy will get me nowhere, but a quick question if I may - what size injectors and fuel pressure are you running?

Ian

The VF22 is massive - too large unless you are running some serious mods.

The VF30 is used on the New Age STi, and is also available in VF34 variety with a roller bearing core. However, it is a big capacity compressor and you are unlikely to use its capacity.

The VF23 could be a good option, but has a large exhaust housing and you will suffer poor spool up.

The VF24 has the same compressor side as the VF23, but a smaller exhaust housing and hence will spool up better than the VF23 but worse than the TD04.

I don't understand the differences between the VF24 and the VF28 and VF29!

As an alternative you could consider a hybrid (as suggested by AdamM), but the quality is down to the people that do the work for you. However, if you get your current core reconditioned this is likely to work out as the most cost effective route!

Duncan
(Waiting for his VF34 to arrive - still)

Edited to add a link to the MRT site and their views on turbos.

[Edited by BugEyed - 3/21/2002 2:55:03 PM]

WREXY

This link is where I got my info from on the differences of the VF24, 28 and 29.

Wrexy.


[Edited by WREXY - 3/21/2002 3:10:00 PM]

catflap

is it worth a massive turbo if its only realy flys at 6000rpm +

sorry i may be missing somehting hree but arnt you changing gear asap, and dosent this make for a very dfficult car to drvie fast throught the gears (track or twisty road)

Would it make the car more of a streight line monster? vs a nible quck car around bends

Its all very interesting

iain atkins

Thank you all for your comments.

I am really just interested in what to replace my turbo with when it gets worse. If you could get a VF24, VF28 or TD04L for the same price, which would you go for and why?

Cheers then



Iain

BugEyed

Iain

I would go for a VF24 or VF28 over the TD04. The TD04 is straining throughout the range above 4,500 rpm on standard boost and probably lower rpm on raised boost. Whilst it will hold the standard boost to c 5,500 it is doing so inefficiently and is causing the intake temperatures to increase. If you are running a top mount intercooler - particularly the "relatively" small one on the "classic shape" UK cars (P1 excepted) - you will get less mass of air actually into the cylinders, and hence less power. The effects of this would be reduced by a front mount intercooler.

Fitting either of the VF24 or VF28 will give you more power for a given boost level, particularly above 5,500 rpm. However, you will suffer from spool up occurring at a higher rpm - pretty much the opposite effect that fitting a de-cat downpipe achieves.

I'd still consider the option of the TD hybrid mentioned by AdamM earlier as another option.

Duncan

PS. WTF is the difference between the VF24 and VF28? I can't see any significant changes from the specs.

Edited to add - Iain, when you say you don't want it to be laggier, do you mean lag (eg the time taken when flooring the throttle at 1/2 throttle to getting maximum power) or the spool up point (eg the point where full boost is available). In theory the VFs will be slightly laggier as their roller bearing assemblies are heavier, but I couldn't detect it when driving one. The spool up point will be worse as previously described, but you very quickly get used to it. If you have driven the new STi and a WRX you'll have felt the difference between the VF30 and a TD04. You get used to it remarkably quickly, and just keep the revs up slightly more to avoid the problem. Perhaps somebody like Dave T-S might like to comment on that?

[Edited by BugEyed - 3/22/2002 11:01:51 AM]

BugEyed

Catflap

The bigger turbo will give more power from 4,500 upwards even on standard boost. But, the main reason to do it is to give the potential to further raise the boost without suffering diminishing returns (see John Banks experiences). Also, Iain seems to feel that his turbo requires replacing / rebuilding anyway, so the cost of upgrading is much less than replacing a "good" piece.

Duncan

iain atkins

Duncan,

Hit the nail square on the head m8

I figure that rather than get my old one reconditioned or replaced by another TD04 i may as well upgrade to a rollerbearing.

Just got to decide now

Thanks for everyone's advice so far.

Cheers



Iain

Adam M

bugeyed,

I am sorry but the VF22 is not massive. I can show you a piccie of a turbo next to a vf22 which shows you how small it really is!massive

from the outside it is practically identical to a vf23. I was also under the impresiont hat it the compressor wheel is exactly the same size as the vf23, the only difference being the blade design of the compressor.

R19KET has just informed me that the vf22 actually has a slightly larger inlet.

All VF series (pre 30) have the same core which has an integral impeller wheel which cannot be changed.

The only differences therefore between all these turbos as standard is the compressor wheels, and the exhaust housings they put over them P19 or P20.

Apparently the VF30 is completely different.

When a turbo is hybridised eg by TD, they change the compressor wheel and modify the housing to accept it. They also can flow p18 and modify its wastegate button to enable it to flow more gas and hence more power up the top, without the expense of spool up.

In this respect, I would consider one of the TD hybrids, which can give you as much flow as a vf 22 but with the spool up of a vf23 or less. They benefit from a much more modern blade design taken from other makes of turbo (eg garrett) and as such can be vast improvements over the now very old designs of the standard wheels.

BugEyed

Adam M

OK, the VF22 isn't a patch sizewise on the big Garretts - unusual for me to be OTT.

However, it does have a larger compressor housing and wheel than the VF23, and is a touch on the large side for a relatively standard UK car.

Iain

The roller bearing is not necessarily better than a plain bearing. It will respond slower (due to increased rotating mass) and is less resistant to shock (scuppering your plans for anti-lag).

Duncan

[Edited by BugEyed - 3/22/2002 1:12:56 PM]

Adam M

duncan, agreed.

I do think the vf22 is way too big for a relatively standard uk car, in the same way that the TD04 is too small if you wnat to put on a fmic.

I was always under the impression that the roller/ball baring turbos actually spool up faster. I would have thought the inertia of the ball barings was negligible comapred to the inertia of the core. If this were the case then why is the GT series garretts spool up faster than the older T series.

Further to this why would anyone buy the vf34 when the vf30 is harder weainr (antilag resistant) and spools quicker too?

Have I missed a major point?

scoobysnacks

Adam (My names Adam as well btw...)
Just wondering about the VF22. you say it's too big for a relativley standard UK car, but does that mean in the same way it's too big for a Jap car as well like my MY98 WRX which I beleive has this turbo as standard? Does the Japanese ECU or intercooler or whatever help with spool up time in some way compared to if it was in a UK car? It does seem to be fully spooled up by 4000 rpm, which is ok, but if I want an earlier spool up, apart from the usual downpipe and ECU mods could the turbo itself be modified eg the blade design or would this be vey expensive?

Adam M

Adam,

the differences in the engines come down to the valve train, and the ecu.

The Uk car redlines at 7000 rpm so immediately the bigger turbo has a smaller band with which to deliver its power, the TD04 is therefore immediately better suited to this car as it spools up much quicker, and although it does run out of steam, the gearing is such that it need not rev as high.

Your if I am not mistaken redlines at 7500, or possibly slightly more, so you have more headroom for the vf22 to stretch its legs.

Inercooler wise there is no difference. Your car does have larger injectors so can provide more fuel, which frankly a vf22 needs.

The other big difference is the ecu. The wrx you have is supposed to be fuelling for a vf22, you cannot simply bolt a vf22 onto a uk car happliy as it will over fuel at the bottom and under fuel at the top.

If you change ecu for a programmable one, and the injectors so that they are the same, then there is no reason why a uk car should perform any differently from your wrx, except the 3.9 final drive ratio as opposed to the 4.44 on your car, but that is splitting hairs.

JamesS

Running my VF30 at 1.3 Bar on a UK car.

It is almost as good as the TD04 in terms of lag and boost threshold. The instant 2500 - 2700 hit has reduced, but by 3000 - 3100 the VF30 is better than TD04 and from here till 7000 would leave a TD04 car for dead.........can`t comment on the VF23 / 28 etc etc but my impression is that the boost comes in at 3600 - 3800rpm??

SecretAgentMan

...with some restrictor work my VF24 starts to spool up around 2500, I've seen 1 bar-ish around 3000 rpm (I haven't had time to datalog yet), and 1.3 is reached around 3500.

/J

WREXY

JamesS,

Are you running an aftermarket ECU?

Cheers,

Wrexy.

BugEyed

Adam (M)

I'm not sure why people say that the roller bearing turbos spool up slower. As you say there shouldn't be much difference in the rotating inertia, and there should be lower mechanical losses.

Duncan

Perhaps I shouldn't have repeated reported knowledge without a factual backup. Certainly I've opted for the VF34.

JamesS

running a Unichip + EBC, full exhaust including upipe, flowed headers....

WREXY

Cheers JamesS.

Wrexy.