Advice please: VG30 vs Hi Flow

[4door_Sleeper]

Looking for advice from those WITH EXPERIENCE - no rumours please

My std RB25 turbo looks like its shot. I will find out for sure next week, but it is very slow to come onto boost and we suspect its either broken the tips off of the impeller or the wast gate cap is leaking.

My dilemma is that I wasn’t expecting to replace the turbo just yet so funds are tight.

Mods on the car include split dump. 3 inch exhaust, Power FC, Shift kit on my Auto Trans, Front mount, Pod filter, Fuel pump and rising rate regulator

I would prefer not to stick on a second hand Std turbo, so my choices seem to be a high Flow ($1900 from GCG), a second hand HKS2530 or 2535 (but I can't find any for sale right at the moment) or I have been offered a VG30 (cheapest option)

Is the VG30 any good on the RB25, and what are the issues?

- I have been told I will need to modify the water and oil lines (no real problems I believe if I can grab a friends flaring tool and some copper line)

- I have been told the 90degree snout off of my std turbo will need to be bolted onto the VG30, but that it will bolt right on)

- I have been told that the dump pipe will bolt straight on.

Is the VG30 much laggier than std?

What potential will it offer?

Can boost exceed 14psi, or will it push more air at the same pressure than a Std.

At the moment? I have 180rwkw, am I expecting too much if I hope to get 220 with a VG30.

[4door_Sleeper]

anyone ???

[Guilt-Toy]

There are a few different types of VG30 turbos.

Which one is it ?

I believe they come out in a smaller version (Twin turbo Z32 version)

Big version (Vg30 single turbo) which is the turbo you want to buy

Big version with steel rear wheel (You have to be very lucky to score one of these)

If you get the first turbo i mentioned it will probably be smaller then the rb25 and only offer you less gains in power and effieciency.

If you get the second one then it will be a little better. These turbos are BB so lag is not an issue. (However you will be limited to the 14psi limit)

If you get the third turbo then your one lucker motha.... Grab it run 16psi and it will go much better then a RB25 turbo. You will get a little more lag but will probly not even notice it with this turbo. Dont hold your breath trying to find one of these because you just cant

Send me a PM and let me know what you go for once you work it all out..

L8r

[Guilt-Toy]

You might be able to bend the water and oil lines into place also. Cant remember exactly. Shouldnt be tooo much of an issue on a RB25.

[4door_Sleeper]

thanks Guilty

I am looking at a big VG30 today. If it has a steel rear wheel I'll grab it.

Do you know if all of these came as ball bearing type, or were some bushes?

[GunMetalR33]

Another thing to note is that the GCG quote of $1900 for the hi-flow is just that, a quote. I have heard people on this site claiming that they got it done for figures around $1300...

You might want to give em a call and see what they say.

[Abo Bob]

1550

[Kaido_RR]

im interested in the VG30 info also,

as my turbo is unknown (not factor r33 turbo) and it belived to be a BB vg30 turbo possable but the factor oil line, fits directly onto my trubo

[4door_Sleeper]

The VG30 I saw today was a BB unit, and when I put it up against a stock 33 GTSt turbo the fittings (oil and water) all looked the same.

Looks like this is the budget upgrade for a 33

[Kaido_RR]

thanks for that info 4door,

is there is hope for my trubo,

does anyone know how to tell the differenets between the 3types?

All i know is that it is BB, and all the oil,water lines r direct bolt using factory lines

[knore]

Yeh GCG website prices are majorly inflated,

The average is around $1600.. a little higher if you get a new actuator which is a good idea. You get new gaskets included with the highflow as far as im aware.

for that price, there is nothing that beats it;

You get a BRAND NEW turbo, with steel wheels capable of handling upto 25psi and has made 250-260rwkw on a number of RB25s at a little over 1bar...

And it goes on the same way it came off

Simple as that

[4door_Sleeper]

I spoke to GCG and they wanted $1900 for a hi flow with ball bearings, and $1300 for a bush bearing. At the end of the day I would still have fairly stock turbo that could flow a little bit more.

The VG30 costs less than $400 and also looks like its a straight bolt on option, and if I do decide to hi flow a turbo the VG30 has a bit more scope again than the std turbo.

[ONALL4]

I was told that the VG30 and the RB25 turbo's have the same compressor A/R but the VG30 has a larger A/R exhaust housing, if this is true why not just stick with your own turbo which you know the condition of and bolt the VG30 exhaust housing on.

[BOOSTD]

The bb VG30 is a direct bolt-on, It has the same 42mm turbine wheel with a .8A/R. The comp wheel is slighly smaller than the Rb25 turbo but A/R is the small. The Big VG30 Has the same comp wheel as the ball bearing but the turbine is 4mm bugger and steel. These will make around 5-10kw more than the RB25 with slighly more lag. The non-bb has 500-800rpm more lag but can run 20 psi. 20psi however is not very useable with Aussie fuel and the un-modded high comp RB25 engine. You will hard pressed to get a good VG30 now as they are getting long in the tooth. The best by far but quite rare is a VG30bb with a thicker shaft which can push past 15psi without reliability issues. You can identify them by the larger nut on the compressor wheel.

If yours has thrown a blade why don't you install a new comp wheel, it will cost a stack less than a replacement turbo. Could even go slighly bigger at the same time....talk to bill at ATS. He helped with my $350 260rwkw VG30 hybrid.

[tridentt150v]

GCG $1169.40 for hiflow on a '98 Gts-t std turbo with new bearings, it was already bb std.

Can't skite about the power yet, gotta install a pfc and adj. ex. pulley and get a dyno tune.

[knore]

I spoke to GCG and they wanted $1900 for a hi flow with ball bearings, and $1300 for a bush bearing. At the end of the day I would still have fairly stock turbo that could flow a little bit more.  

The VG30 costs less than $400 and also looks like its a straight bolt on option, and if I do decide to hi flow a turbo the VG30 has a bit more scope again than the std turbo.

It flows more than a 'little bit more', the highest ive seen is 260rwkw on 1.2bar

And thats only 1.2, put in 1.5 with the support systems it might push it to 270-80.

Not to mention the lag is almost non existant, it follows the standard turbo till it runs out then pushes another 50-80kw on top of that.

thats alot more compared to the standard turbo and pretty much the same as the VG30

GCG $1169.40 for hiflow on a '98 Gts-t std turbo with new bearings, it was already bb std.

Can't skite about the power yet, gotta install a pfc and adj. ex. pulley and get a dyno tune.

Yet another one thats not even close to the stated prices

Thats ridiculously cheap, be sure to post how it goes. Did they say why it was cheap? Cos its a later model?

[zoom]

GCG $1169.40 for hiflow on a '98 Gts-t std turbo with new bearings, it was already bb std.

Can't skite about the power yet, gotta install a pfc and adj. ex. pulley and get a dyno tune.

Is it bush bearing or bb high flow?

i was qouted $1950 to high flow with new bal bearings. GCG said that they can do for about $1200, but it's a bush bearing instead! :flamed:

[BOOSTD]

Maybe $1169.40 if the bearings are ok to re-use...

[Cubes]

I've had a the VG30DET BB turbo from a Leopard that makes around 190kw at the fly on 6-7psi. It was ball bearing and had a ceramic exhaust wheel as all the new turbo's do.

The older much older versions are initially non-ball bearing, the even older versions again are both non-ball bearing and have a steel exhaust wheel.

On the RB20DET it was a laggy POS with stuff all mid range power but more over around 6000rpm (which was useless).

It also made the exhaust much louder with a really pain in the arse drone.

I would think on the RB25 you could shift the power band down around 500-600rpm.

On the RB20DET it was making 11psi by 3900rpm (stock turbo did this by 3100rpm).

I had boost set to around 13-14psi where it was being made by around 4100-4200rpm.

So on the rb25 I would expect it to spool to around 11psi or so by 3400rpm. Which from my understanding it quite a bit laggier than the stocker, the rb25 I drove made 11psi by 3000rpm.

Everyone has their own idea of when a turbo makes boost.

I use the method of taking off normally in first then change in to second and plant the foot.

Remember also the VG30DET turbo has a smaller compressor than the rb25 turbo.

It may be possible to use the compressor from your rb25 turbo and use the vg30 exhaust wheel & housing... not sure.

As already mentioned speak to Bill at ATS on Marion Road.

I would look at the vg30det turbo as a last ditch option.

Stick with the smaller exhaust a/r.

Peak power isn't everything especially in an Auto.

[BOOSTD]

It may be possible to use the compressor from your rb25 turbo and use the vg30 exhaust wheel & housing... not sure.

As already mentioned speak to Bill at ATS on Marion Road.

 

I would look at the vg30det turbo as a last ditch option.

Stick with the smaller exhaust a/r.

The VG30bb and Rb25 turbines are the same. The VG30bb housing does bolt on to the RB25 turbo for a 5-10% power increase.