GS-Racing Holset turbos

[urq20v]

Has anyone tried a Holset from these people?The price looks good at £450.00 each.I am looking for a HX-40 and these seem to have been optimised for our type of use.

http://www.g-s-racing.com/

[Billman]

If they are genuine holset, then its very good! Watch out for the turbine housing as the 12 maybe too small for our engines (depends on goal etc)

[A80Avant]

is that divided?

[Billman]

yes, everything above 9 at holset is divided except the hx30 housings AFAIK

[urq20v]

Are there any problems running a divided exhaust housing on a non divided manifold such as a Wagner tubular.

[urq20v]

I have just read a contentious thread regarding the GS-Racing turbos on the Driftworks forum and it appears that these are Holset "style" turbos.They are made from parts sourced from around the world (Japan among others) and built in the UK.

http://www.driftworks.com/forum/tech...hx35-help.html

[quattro84]

These are complete fakes! Although the quality doesn't look that bad i wouldn't use them.
I had contact with these guys and they couldn't give any info about their products, even wheel sizes was too hard to find out.

[quattro84]

Are there any problems running a divided exhaust housing on a non divided manifold such as a Wagner tubular.

Nope, no problem. It just affects efficiency because more energy gets lost to warm up the extra material in the turbine housing. It's negligible

[urq20v]

These are complete fakes! Although the quality doesn't look that bad i wouldn't use them.
I had contact with these guys and they couldn't give any info about their products, even wheel sizes was too hard to find out.

Interesting.I emailed them last night asking for info on a turbo capable of 450kw suitable for the Audi 20v I5 and received an answer in less than 10 minutes.
This is the reply I received.

"for that power it would have to be the 7 blade hx40 with the 14cm rear housing,with the following wheel sizes for compressor and exhaust wheels"

inducer 58.92
exducer83.2

inducer 73.78
exducer 64.

There was no AR specified.

How this compares to actual Holset applications for the I5,I dont know.

[A80Avant]

that is the turbo i tried, but genuine holset Super HX40 with the 0.70AR from the US. Turbo was fine but A LOT of lag. I dont know what the 14cm hotside equates to, but if i were to ever try an HX40 i would go for the 0.53AR at most for the I5, unless im building a drag car in which case i wouldnt mind.

That setup i had, gave me full boost on 3d gear @ 4600-4700rpm.

Maybe on the 0.53AR it would have been better.

[Billman]

when do you hit full boost now with the GT30R?

@urq20v
the holset 7 blade hx40 has 60/84 compressor.

[A80Avant]

full boost on 3 gear i have on 4100rpm (2.1bar)
on holset i only had 1.7bar at 4600-4700rpm. Also with that hotside, lag was apparent on all gears wearas on the GT it comes in much sooner on other gears. Also the GT is the 0.82AR as well and has better EGTs than the holset(something which i couldnt understand really, but i get better EGTs on the GT with 2bar to the redline than holset with 1.7. (same AFR)

[A80Avant]

with that said, i think a smaller turbine housing could be better for spooling, but im not sure about EGTs

[urq20v]

full boost on 3 gear i have on 4100rpm (2.1bar)
on holset i only had 1.7bar at 4600-4700rpm. Also with that hotside, lag was apparent on all gears wearas on the GT it comes in much sooner on other gears. Also the GT is the 0.82AR as well and has better EGTs than the holset(something which i couldnt understand really, but i get better EGTs on the GT with 2bar to the redline than holset with 1.7. (same AFR)

Just out of interest,what ECU are you using.Were the Holset and Garrett each mapped on a dyno for optimum performance?There are quite a few Holset users who claim equal or near equal spool to the Garretts despite the Garretts having ball bearing centres.

[A80Avant]

That was the reason i went to holset in the first place. There is a comparison of a garret 3076 vs holset on the mitsubishi forums and that was with the 0.53AR (on the holset) and i dont remember the garrett whether it had the 0.82 or the 0.63ar.

Mapping was done by me, and i use VEMS. The setup was excactly the same, and on the holset i even had a larger downpipe than the garrett. They were not mapped on a dyno, but on the road, and i used the perfomance box for a few runs.

By datalogging alone, i could see the vast difference in spool and lag between the 2 turbos. In holset's defence, i did not take it to 2.1bar as i do now with the garrett, but if i want to be strict in comparison between the 2, the garrett may give you the 1.7bar which i used on the holset at about 4000rpm on 3d gear, when the holset will give it at 4600-4700. That is on the SAME car with same timing and fuel. Now i tried many different things to get that turbo to lag less, such as stiffer spring on the wastegate faster throttle responce, and it didnt work because the fundamental mistake was the large hotside. If i had used the 0.53AR, i would have probably matched the garrett, or the difference may have been negligable, AND because the holset can easily go above 2bar of boost, it would probably be able to make much more hp.

The holset is quite bigger than the 3076 and can be matched with the GT35 really. But if you want it to drive it daily, you either need the 0.53AR or one of the holset turbine housings that is small.I have never tried the holset turbine housings, so i cannot say which one would work best.

The other option is to machine a hotside to fit the turbo and match your liking, but that is something i wasnt willing to try. I went to a tried solution, and with what i had in hand, i think for a daily driver on a 2.2 the 3076/0.82AR is the larger turbo you can fit IMO.After that it becomes too laggy for my taste.