Holset Hx35w Installation In Standard Low Mount Position

[CEF11E]

I have just started the process of replacing my turbo in my R32 with a HW35W holset turbo. there has beenquite a bit of stuff on them floating around lately and I needed something that would produce near 300rwkw on my RB30det.

The standard turbo has been removed and the first tash was to see if it would actually fit in the standard lowmount position without major modification.

As suspected the compressor housing fouls on the exhaust manifold. it fouls on one of the standoffs that are cast in the manifold for the heat sheild to screw into. it also fouls on one of the runners and a spacer will be needed to make it fit. Apart from that it clears the engine mounts and everything else easily and looks right at home in the engine bay. I will have to make up the following bits

1. Dump/front pipe, The exhaust flange of the holset is a 5 bolt that LOOKS like an XR6T but is slightly different and wont fit. this means I have to make a flange from a steel plate. not really a big deal.

2. new turbo intake pipe, the mouth of the holset is 4" so a silicon reducer and some 3" pipe will do the job nicely.

3. compressor outlet pipe will have to be modified. it needs an elbow welded to it. once again not really a big deal.

4. I have to find the right oil fitting bit it will screw right onto my existing braided line.

There will have to be a spacer between the manifold and the turbo and I estimte it will have to be around 20mm thick. I guess I will have to make that. but should not really be a drama..

The 1 thing need a bit advice with is the studs in the manifold. the 4 that connect to the turbo. they will have to be removed and replaced with ones 20mm longer. as these are not a standard part I have no idea where to look for them.

Also How do you remove the existing ones? do they screw out? and if so do they unscrew anti clockwise?

I will keep this thread updated with pics and info as the job is done.

Cheers!

[Dale FZ1]

The 1 thing need a bit advice with is the studs in the manifold. the 4 that connect to the turbo. they will have to be removed and replaced with ones 20mm longer. as these are not a standard part I have no idea where to look for them.

Also How do you remove the existing ones? do they screw out? and if so do they unscrew anti clockwise?

Great work Nic - have a go. Should have some prospect of a driveable match to the 30DET, depending on impeller and housing specs. They seem so variable depending on original fitment. Make sure you post some pics up, and this thread should probably be moved into the 3 litre section eventually.

If your housing is split pulse, then the spacer plate should be cut to accomodate that. You might be surprised what's available from the US, as there is a reasonable number of these things being installed on BMWs. Worth a quick search before asking someone to do a one-off, considering the labour costs associated, and also you're likely to get something laser cut and a very accurate match to the ports on manifold and turbine.

For studs look to any half decent exhaust shop, truck parts supplies (maybe, but usually not many metric parts available), or an engine reconditioning workshop.

Studs will just screw out, they run a conventional right hand thread. Use either a double lock nut, or vice grips clamped on nice and tight. Recommend spraying some WD40, Inox or Lanoline on the studs and leave it penetrate a day or two before having a go, and don't be that surprised if you have one break.

[CEF11E]

Cheers Dale will do..

the turbo is the higher flowing hx35 compressor and the 12cm housing. I am not really after huge power bu it still should make 300rwkw.

thanks for the tips on the studs, I will hunt around for them, I am lucky enough to have access to a full workshop so I should be able to make all the bits I need.

On a side note,

I can't believe I never noticed this before but the factory RB20 manifold is like a split pulse design with 3 cylinders feeding each port. and the turbo I am fitting has a split pulse housing. I was going to knife edge the exhaust housing but now it looks like a split t3 spacer will do the trick!

[zachscalais]

ive just done exactly the same turbo swap, we opted to make an adapter flange to instead of forkin out around the $100mark for one off egay, all i can say i ur lucky you dont have to make a T4/T3 split pulse flange haha not fun! anyway i think you will be very happy with the tubo once its running, i am. if you need pictures off anything let us no.

oh and also i was lucky enough to get an exhaust flange that a fella in the uk had laser cut for only $25, so have a hunt around and you mite be able to find somthing like that?

[CEF11E]

Hi zach,

yep if you could take some photos for me that would be great! I am interested in looking your dump pipe and the intake pipe to the turbo. did you use a 3" steel pipe and a 3 to 4 silicon reducer?

Have you had it dynoed yet? I remember you said it replaced a gt40 or something? if you have not had it dynoed, what sort of power do you estimate it is making and at what boost level?

cheers mate!

[Cjmartz2k]

Can't wait to see results on this...........................AND PICS!!!

[CEF11E]

I have all the bits I need on order now and should have the install completed by the end of next weekend,

Looking at the standard RB20/25 manifold, it is a SPLIT PULSE design.... am i the first to notice this? and why did i not notice this before? 3 runners go to each side and interestingly, each runner has close to the same internal volume. There is an expansion slot/cut in the middle of the split in the manifold. I am going to weld this up. I am then going to make a T3 split pulse spacer that is 20mm thick. otherwise the compressor will foul on the exhaust manifold.

The other modifications needed to make it fit on the manifold are to remove the manifold heatshield and cut one of the manifold standoffs that the heat shield bolts onto. then the heatshield has to be cut to clear the compressor housing.

20mm spacer is about the minimum and maximum at the same time. this leaves the turbo about 8mm clearance to the manifold and about 55mm clearance between the turbo and the strut tower. so there is plenty of clearance but by no means is this a small turbo,

everywhere else looks to be fine, it clears the cross member (this is on an RB30det mind you so I have an extra 28mm clearance as my block is 28mm taller than an RB20.

The oil supply for my HX35 has a fitting I removed and then the standard nissan banjo will fit but you will need a new banjo bolt. the new bold needs to be 12mm with a thread pitch of 1.5. i bought the bolt from pirtek for about $9

the oil drain is the same as your stock turbo.

the compressor inlet is 4" so a silicon reducer will be used and i will be making up a new intake from the airbox to the turbo.

the compressor outlet is a vband flange and it will be ground down and a silicon hose will be clamped to the housing. but an elbow will be needed as the stock nissan turbo has this fitted from factory.

the dump pipe is being made from scratch and this will be the biggest item to make as I have to make the flange from scratch. I have bought 8mm steel plate and 3" mandrel bends. This will be my first attempt at serious welding and will have to be done on a gassless MIG so it will not be pretty but will be strong and have good penetration.

Thats about it, the only other thing that has to be done is block off the water supply lines, one on the drivers side of the engine that goes around the rear of the block and one that bolts to the passengers side of the block.

I will also have to upgrade my injectors and afm before it can be tuned and I will be capping power at 270rwkw to keep the stock RB30 bottom end alive. I MAY lean on it a bit harder on the dyno just to see what it is capable of but the DSM guys have already done this and have proven 500rwhp is doable from these turbos. this is on a 4G63 so even on a 2 litre these make insane HP.

The best thing about the install is the car will still look stock to the untrained eye and will make 300odd rwkw I know you dont believe me it will look stock but i will take some photos when I am done to show you what I mean

Cheers!

[Lithium]

You're definitely not the first to notice the fact the sets of 3 cylinders are separated in the factory log manifold, I've pondered it and decided that I'd still rather use a custom manifold if I went to a larger twin scroll turbo though it is interesting to note and I am sure it has its advantages even with a single entry turbo.

I look forward to hearing how the HX35 goes as I got SO close to getting one for my own Skyline years ago before I ended up settling on the GT30R.

[Adriano]

Curious, is this internal wastegate?

[Dale FZ1]

The HX35W (for wastegate ) designation indicates it is internally gated. Any pics I've seen show only one valve, however none of the BMW installations have complained of poor boost control that I've seen. Most often there has been a bit of biff n barge about whether the owner has got optimal performance from a truck turbo on a petrol engine, whether they should have spent more money and got something "better" etc.

When I first became aware of these units, the biggest problem fitting them that I could determine was likely to be physical size - but evidently they require spacing much the same as the Garrett GT30 IW units.

Edited May 26, 2009 by Dale FZ1

[Dale FZ1]

Looking at the standard RB20/25 manifold, it is a SPLIT PULSE design.... am i the first to notice this? and why did i not notice this before? 3 runners go to each side and interestingly, each runner has close to the same internal volume. There is an expansion slot/cut in the middle of the split in the manifold. I am going to weld this up.

the compressor outlet is a vband flange and it will be ground down and a silicon hose will be clamped to the housing. but an elbow will be needed as the stock nissan turbo has this fitted from factory.

the dump pipe is being made from scratch and this will be the biggest item to make as I have to make the flange from scratch. I have bought 8mm steel plate and 3" mandrel bends. This will be my first attempt at serious welding and will have to be done on a gassless MIG so it will not be pretty but will be strong and have good penetration.

Nic you might find that by welding up that slot in the collector divider that some stressors are introduced into the manifold. Could be counterproductive if it induces cracking, and you might find that the manifold requires facing after the heating/cooling of the weld process. Main point is that the gap is so small I wonder if it would produce any quantifiable result for the effort?

A cast alloy elbow could be easily and cheaply welded to the compressor outlet., making for a bit tidier plumbing. I did so with my GT3037, no problems.

The dump pipe flange might be better done with either 10mm or even 12mm plate. More metal to play with should = less movement/warping when you weld. I think the result will be better than using that cast V band outlet you see them sometimes come with. That casting does not look like a good flowing bit of gear, more suited to quick removal for servicing than anything. Work on a big diameter dump - 3.5 inch should fit in that area without much problem.

Otherwise all good, keep us posted.

Edited May 26, 2009 by Dale FZ1

[Adriano]

Is the wastegate flap cover passages for both sides of the housing. You may want to look at upgrading to an rb25 manifold, as they are a little bit better than the rb20 ones if my memory serves me correctly.

[CEF11E]

thanks for the support guys,

I got a bit of work done tonight.

I did end up getting thicker plate for the rear dump flange and cut it and after a lot of work ended up with the bolt holes and a 3" hole cut to fit the dump pipe. it needs a bot of work but will be good when finished, Ideally I would have gone the standard rear plate and dump but i could not locate one apart from new oem and it was a couple of hundred a 2 weeks away so i made my own.

and Dale I think you might be right about the manifold, I will leave the expansion gap there. it's only 6mm long and 3mm wide so shouldn't cause problems.

I did however find the actuator for the internal gate needed to be modified to fit. this was because the compressor housing fouled it in the position i wanted to use. so it was cut and new holes drilled. but it fits nicely now. the actuator has a screw threaded rod so its going to be easy to adjust boost for what i want. I was going to mad it anyway as the standard pretension on the gate is 24psi. its now set to about 12psi and there is enough thread on the rod to increase it to around 19psi so still a good level of adjustment

Sorry about the lack of pics so far, I will have some up on the weekend.

[SLAPS]

How do you find the stiffness of the HX35 actuator?

The spring is rock hard or fairly soft? (can be pulled out easily providing u are holding on to something with it i.e vice grips)

[waxer52]

I'm also at about the same point as you, only my holset has a hx40 compressor and a hc1 turbine (same as hx35 without the internal wastegate).

The spacer I need for the manifold is 40mm thick. I was going to make a spacer with a piece of steam pipe in the middle to fit a wastegate, but it is just too tight.

It will however fit with the 40mm spacer and I will weld a steam pipe elbow to the turbine housing.

Has anyone got any good links for the welding of mild steel to cast, whats best tig, stick, maybe oxy-acet).

Best of luck with the internal gate mate and I hope it will keep boost regulated properly, if it dosen't you can always weld to the exhaust housing and do an external gate like I'm doing.

[Cjmartz2k]

A lot of the DSM guys reccomend porting the internal gate to almost match the size of the flapper, and radius the entry. I seem to remember somebody having trouble getting the boost to stay below 20psi on the internal gate, and after porting it would hold down to 10psi no problem. This is on a little 2.0L remember.

[CEF11E]

How do you find the stiffness of the HX35 actuator?

The spring is rock hard or fairly soft? (can be pulled out easily providing u are holding on to something with it i.e vice grips)

The wastegate spring is rock hard. to even move it 5mm you need vice grips.

I now have the turbo bolted to the manifold and it is a tighter fit that first measured. I made a 20mm split pulse spacer out of a a pair of 10mm T3 flanges and bit of flat bar 6mm thick. then I had to make longer studs. I used hi tensile threaded rod and cut 4 pieces then chamfered the edges and bolted them into the manifold with hi temp locktite. I have also finished the dump flange and will make the dump pipe over the next couple of evenings.

There are some bits I did not envisage,

1. the power steering lines from the resivoir to the pump on the low pressure side do not clear the compressor snout!!!!! I will have to have a flexible ps hose to rectify this but it's not really a big drama.

2. even after modifying the actuator is STILL does not fit!!! it also fouls on the power steering canister.

I can explain how much bigger one of these turbos are so I will just do it with a picture...

to the left is a TD04. (same size as RB25 turbo) to the right is a Holset HX35

Waxer52,

Good luck with your install, If you need a spacer that big I am guessing you will have to put the turbo and manifold on the car in 1 go otherwise you will never squeeze the turbo in there. That's also a big spacer! make sure you have some good bolts and the spacer is strong enough to bare the weight of the turbo. Add some photos to this thread when you get a chance...

Cjmartz2k,

Yep I thought of boring the wastegate flap, and might end up doing it. there is not much material between the flap and the edge of the hole alreays. piossibly 2mm each side. but even taming 1mm off this will increase the flow of the hole by 26%!! so it might be a good idea,

My workshop looks like it was hit by a bomb made of skyline parts, metal shavings and beer bottles at the moment

[Lithium]

Yeah that size stuff was the deciding factor on me going GT30R instead of HX35, I had one right there to go with but wussed out - the GT30R is enough of a bitch to work around if I need to change gaskets etc haha.

[Cjmartz2k]

Yeah, they aren't tiny for sure! That's not your HX35, right? You said you had a higher flowing model which is the 7 blade, right?

[CEF11E]

yep I have a 7 blade hx35. I just used the picture as an example