Holset Turbo's

[crack]

for all you guys wanting to run a holset on your rb (or other engine) i can draw a flange adapter in cad so you can go to any laser cutter and get one made. someone just needs to give me the dimensions of the holset flange. i already have the t3, t4 etc drawn already.

[daniel23a]

Thanks Crack, the HX35 flange is already T3 divided, but a spacer will be needed if using stock manfold. can anyone tell me if it will fit in a stock low mount position on an R33 GTS25t?

[works 510]

I had a look "CEFF1E"s car which had a stock exh manifold with from memory had a 20mm spacer.

This was in a rb30det R32.

Apart from the ext wastegate, such a sleeper engine bay!

[crack]

Thanks Crack, the HX35 flange is already T3 divided, but a spacer will be needed if using stock manfold. can anyone tell me if it will fit in a stock low mount position on an R33 GTS25t?

thats cool. you then need two t3 divided flanges. i have that as a dxf file.

do all holsets have a v-band outlet? if not if someone has one out of the car, give me the dimensions and i'll draw it up for you

[daniel23a]

thanks works, yeah i have read his thread, my concern is the different size of engine bays and block heights, i have been told by others that i will need to cut into the subframe or engine mounts which i don't really want to do. was hoping there was someone who has tried to fit one already. anyone?

[WizardBlack]

I have an R33 RB25 on the engine stand right now. It's almost ready to go into my 280Z. To answer your question, I have a 7-blade HX35 and it does not clear as a direct bolt-on. For the oil feed, the factory line fits, but the stock RB oil feed banjo bolt on the stock turbo is 12mm x 1.25 while the Holset requires a 12mm x 1.50. The oil drain line fits up as per factory. For the eliminated coolant lines, a 14mm x 1.50 oil drain bolt will plug the banjo hole off on the block.

I have seen people find an appropriate banjo bolt from another application and made it work. I have also heard people take a standard bolt and drill it to banjo specifications. Note that the stock banjo bolt acts as a restrictor. I don't think the Holset really needs a restrictor to avoid issues, however.

The only issue is that the turbo fouls the exhaust manifold at the compressor cover. If you clock the compressor output straight towards the block (in other words, a useless clock position) it will clear since the radial diameter changes, etc. With the compressor outlet pointed down, it will not clear. I suspect you merely need another T3 flange to be used as a spacer when you mount the turbo to get it to clear, but I have not tried this yet. Note that, as others stated, the turbo and the stock exhaust manifold are both twin scroll. I have not found a twin scroll "u-weld" flange to space it out. Likewise, you will need longer studs for the exhaust manifold.

Note that the exhaust manifold studs are dual thread. They are 10mm x 1.25 on the turbo side and 10mm x ??? on the manifold side. It's a coarser thread spec, but I have not measured it yet. The holes in the exhaust manifold for the studs are obviously blind, so you could just get some high grade threaded rod and cut them to length, etc.

Please note that I have NOT tested fitment with the factory engine mounts, as I am doing a swap into another chassis and did not use the original mounts. I have them however, so I can test it out if anyone is interested.

As a side note, another nice thing about Holsets is that the compressor wheel is balanced individually (on the '35' sizes, and some others) and the turbine wheel and shaft assembly is balanced individually. This means you can rebuild it without indexing or having it rebalanced. Just pull it apart, stick the new bearings in, and slap it back together.

Edited May 22, 2010 by WizardBlack

[daniel23a]

Would be much appreciated if you could fit up the old mounts Wizard, i am wanting to keep it low mount and this will determine whether i can go for an hx35, if it requires modification i'll probably go for something different. cheers!

[daniel23a]

Any luck? I am waiting with eager anticipation

[DanShirts]

A few months ago I said I would post a dyno chart of my HE351 RB20. I'm a little late, but here it is:

327 RWHP and 255 FT/LB

My spark timer is broken, so the RPM scale is a little screwed up. It should end on 7000 RPM.

This is on a mustang dyno at about 580 meters above sea level.

RB20 stock internals

Holset HE351 from a Dodge RAM - NOT the variable vein model

4" Downpipe / 3" exhaust

4" Intake

440cc 7MGTE Injectors

ECU Remap

GTR Fuel Pump

Everything else is stock

This is the first car I have ever tuned (without help from a professional tuner). I'm pretty happy with the results, but I know it could have done better.

It was running 18 psi (1.25 bar). I pushed it up to 22 psi and blew the rings out of the 1st cylinder. I have since put a new motor in, cams, and changed back to an RB25 turbo. I will rebuild and run the holset again. But I don't have the money for a rebuild right now.

[Adriano]

Im assuming you are using the stock wastegate, and not an external. IMO this could well have contributed to te failure of cylinder #1, as the manifold pressures of cylinders 1,2 & 3 would be far higher than 4,5 & 6 as the wastegate only feeds off those cylinders, which would mean that the tune would be conservative on the back 3 cylinders.

[DanShirts]

Im assuming you are using the stock wastegate, and not an external. IMO this could well have contributed to te failure of cylinder #1, as the manifold pressures of cylinders 1,2 & 3 would be far higher than 4,5 & 6 as the wastegate only feeds off those cylinders, which would mean that the tune would be conservative on the back 3 cylinders.

Stock WG actuator, using internal Holset WG. My wastegate line was pulled right off the turbo (see pic).

How does the stock internal WG feed off 1-3? My stock rb20 and rb25 turbos have a feed line right off the turbo, just like the Holset. I always thought that on a straight 6, 5&6 would have higher pressure.

I just thought I pushed too much boost and my timing map was a bit aggressive.

[globe471]

hey yall i just got my holset hx35 turbo for my rb25 putting it on my top mont mani

[zebra]

Stock WG actuator, using internal Holset WG. My wastegate line was pulled right off the turbo (see pic).

How does the stock internal WG feed off 1-3? My stock rb20 and rb25 turbos have a feed line right off the turbo, just like the Holset. I always thought that on a straight 6, 5&6 would have higher pressure.

I just thought I pushed too much boost and my timing map was a bit aggressive.

mad old thread revival.

he is talking about the actual flapper on the turbo, only bleeds exhaust off 1 side of the split pulse housing.

[CrimsonLey]

Interesting information on Variable Geometry Turbos. I was thinking about doing this to my RB26 but it looks like the technology isn't THERE yet.

[Andy B]

Bigalow, I have a modified Holset He351vg turbo that I have been developing with a specialist in Canada. This is a HX40

With a unique pneumatic VG control system fitted. This same turbo on a bog stock supra Tt lump made full boost at 2800rpm!! It's destined for my RB26 soon !!!

[CrimsonLey]

Bigalow, I have a modified Holset He351vg turbo that I have been developing with a specialist in Canada. This is a HX40

With a unique pneumatic VG control system fitted. This same turbo on a bog stock supra Tt lump made full boost at 2800rpm!! It's destined for my RB26 soon !!!

You Godzilla32 in GTROC? I was reading the thread yesterday... Please excuse my thread jack but it seems like petro isn't good with VGT per the pressure in the manifold and I doesn't seems very reliable.

[Andy B]

Bigalow, Yeah thats me. The Supra guys have been using these Holset VG turbos for a long time now with no issues....I used to work at Holset in the UK and I was involved in the development of this HE351VE. The materials used to manufacture these things are the same if not better than those used in petrol turbos. Sure EGT's are higher in petrol applications but as all of the materials in the Holset Turbos are exactly the same as petrol turbos this is a lame ass excuse used by haters!!!! lol!!

[CrimsonLey]

Bigalow, Yeah thats me. The Supra guys have been using these Holset VG turbos for a long time now with no issues....I used to work at Holset in the UK and I was involved in the development of this HE351VE. The materials used to manufacture these things are the same if not better than those used in petrol turbos. Sure EGT's are higher in petrol applications but as all of the materials in the Holset Turbos are exactly the same as petrol turbos this is a lame ass excuse used by haters!!!! lol!!

I don't trust UK products.

Joking but the Supra is a different application than the RB. I was thinking about buying a GTX turbo (by Garrette) so I'll probably stick to that as opposed to being a VGT pioneer.

[Adriano]

Bigalow, Yeah thats me. The Supra guys have been using these Holset VG turbos for a long time now with no issues....I used to work at Holset in the UK and I was involved in the development of this HE351VE. The materials used to manufacture these things are the same if not better than those used in petrol turbos. Sure EGT's are higher in petrol applications but as all of the materials in the Holset Turbos are exactly the same as petrol turbos this is a lame ass excuse used by haters!!!! lol!!

You say teh materials used are the same as the petrol, but what are petrol vgt vanes made of?