light info on Holset turbos

[TimsTurbos]

Hey Everyone, I thought I would toss out some info on the Holsets. I’m not here to start arguments. Just like to help out.

There are a few popular holset wheels and turbos in the DSM world.

The H1C, Hx35, Hx40, Hy35, He351…

The H1C is (usually) and 8 blade wheel. It can go from a 46mm inducer all the way to a 58mm. Any of them above the 56mm mark can flow around 500hp. These are more of a first-generation engineering stand point. All great wheels. Designed to do exactly their job. The 8 blade wheel (can) have a more aggressive flow at lower boost. These wheels are not interchangeable with the HX series turbocharges. But, they do usually share the same turbine wheel as the hx35. The popular 60mmexducer by 70mm inducer. So, you can swap turbine hsg on those turbos. There are some odd ball turbine wheels on both but, the 60/70mm is the most popular one.


Ok, now to the HX35!!!! A great turbocharger. Comes stock with 360 thrust bearings. FEED IT OIL!!! I sell A LOT of hx35’s new and reman. 95% of the failures are oil issues. The biggest one is the drive to the dyno with Air fuel lower then 8-9:1. That kills turbos is minutes. Or restrictors on the oil feed line because of a bad return line. But, this blog is not about Oil problems.

The Most popular HX35 compressor wheel is the 7 blade. It measures out 53.91mm. NOT the 56mm everyone thinks. You can find these on the dodge trucks after 1993 to about 2000. This 53mm flows well, I have run 500whp many times. But, you are going to be in the High 20’s to 30’s for boost. And yes, the turbine wheel is usually the 60/70mm. This turbine wheel is very effective. You can run Hx35/40 hybrids on this setup. Just be sure to run a larger turbine hsg.


The HX40 turbocharger. The hx35 and hx40 have the same bearing kits. Also the interchangeable bearing housing. But, you may need to machine out the compressor pocket for the different wheels. The most common hx40 wheels go from 58-60mm inducer. The largest OEM HX40 wheel is a 60mm. They come in 3 way. The 8 blade, 7 blade, and 6 blade. All work great. But, in my opinion the 7 blade is the most efficient one. Much less chance of compressor surge. They spool well and work nice on Hybrids. On a Hybrid I usually get 500whp around 20psi. They will go higher.

The hx40 wheels over 60mm are all aftermarket. The 60mm 7 blade is the same wheel as the HE351 wheel. There are some nice aftermarket 62,63,67mm wheel. The 67mm can have disastrous problems if you don’t match it up with the correct turbine wheel or flow. If you want 67mm flow, I would honestly suggest a different turbocharger. An s300 or something with the correct turbine flow.

The HY35 turbocharger. As for turbine wheels, this changes. The hy35 and HE351 use the same wheel. Also the smallest wheel. Its a 58mm by 65.5mm. Both wheels are fitted with a wastegated 9cm turbine hsg. The are no aftermarket hsg for the HY or HE turbos. They run a different Brg hsg with a v-band clamp. Now the Hy35 comp wheel is a great wheel. It’s a 56mm 7 blade (second gen).

The HE351 turbocharger. As I said before it has the HX40 7 blade 60mm wheel. Good turbo, has better flow wastegate design then the hy35. For a gas 4 cylinder you really need more turbine flow. I have seen these run extremely high EGT’s. I wouldn’t recommend them without mods on the turbo. There is not much interchangeable stuff in these turbos. Also the journal bearings are grooved for cold climate weather.

I will get into turbine hsg. A lot of people have asked about CM2 compared to A/R. I have a chart that helps explain it. I just went over a few point on these turbos. There is much much more. So, if you need any help just ask.

 

[Dsmkauai]

Good info but most of that is already here bro http://www.dsmtuners.com/threads/holset-turbos-part-9.436168/

 

[TimsTurbos]

Yep, I have read that. Good info.. I was just add some stuff. No one really goes on about turbine wheels and the turbine swallowing capability of hybrid rotor groups. Most engine failure is going to be a miss matched rotor. The brute power comes from the turbine wheel and swallowing capability. One of the post show an HX40 running 40psi. Yes it will do it but, check the pressure of the turbine hsg. Most turbine hsg's are casted to a certain wheel diameter. So the A/R or cm2 can change just by making it accept a larger wheel. A true say 9cm2 hx35 turbine hsg machined out to accept an HX40 64mm or 67mm ( yes there are many hx40 turbine wheels) would actually lower the cm2 to a 7cm2 or 8cm2.
If you are breaking the 1:5 to 1 drive pressure rule, you are just adding damage to parts and life. These are DSM questions people call me about every day at my Shop. Just shedding some light. Got plenty more......

 

[Vegas Smith]

Yep, I have read that. Good info.. I was just add some stuff. No one really goes on about turbine wheels and the turbine swallowing capability of hybrid rotor groups. Most engine failure is going to be a miss matched rotor. The brute power comes from the turbine wheel and swallowing capability. One of the post show an HX40 running 40psi. Yes it will do it but, check the pressure of the turbine hsg. Most turbine hsg's are casted to a certain wheel diameter. So the A/R or cm2 can change just by making it accept a larger wheel. A true say 9cm2 hx35 turbine hsg machined out to accept an HX40 64mm or 67mm ( yes there are many hx40 turbine wheels) would actually lower the cm2 to a 7cm2 or 8cm2.
If you are breaking the 1:5 to 1 drive pressure rule, you are just adding damage to parts and life. These are DSM questions people call me about every day at my Shop. Just shedding some light. Got plenty more......

Keep em comin! I have a bep t3 hx35 that I may be throwing on in a few months. Could you talk more about the low afrs while driving to the dyno? I'm not sure I understand what you're talking about and what damage it would cause. Also, is it reasonable for a joe-blow (myself) with no experience to rebuild a holset? Thanks.

 

[TimsTurbos]

Sure no problem. Driving to the dyno on an untuned car is bad.......... Usually everyone wants to be safe and not run it lean.. The would be up over the 14:1 AFR. Thats for a NA car. You will rip though pistons on a turbo car. This is just the lean side of the spectrum im explaining. "if you are running lean, keep your wastegate flapper open. Easy to do on an Internal Wastegate. Not so much of an external. You could just remove the external. The point is to keep the car from going into boost. This type of problem will not directly damage the turbo. Unless a piston goes through the turbine wheel.

I know everyone knows this,,, just a refresher. The higher the number on the AFR the less fuel. SO 14 and up is pretty lean. 12 and down is going to be richer for the turbo cars. just FYI..

Ok, the damage drive to the dyno is rich!!! if you are driving a car 10:1 AFR and lower, its bad. What you are doing is washing the cylinder walls with fuel. It's like spraying break cleaner to clean off the oil. The walls go dry of oil. Then the rings have no sealing power to keep the fuel in the cylinder. At that point your oil in the pan gets diluted extremely fast. That bad oil goes right into the turbo bearings. The oil is not just a lubricant. Its a cooling agent. The temperature of the bearings will go higher then the bronze melting point. This happens in seconds. The famous quote " I only drove it to the dyno 3mi away" That's all it takes..

This is an easy turbo failure to see on disassembly. There is no hiding it. You will see very shape edges on the journal bearing. Turbine Brg I.D. is usually hollowed out first. This is the turbine head heat transferring. The bronze will plate the turbine shaft and give a gold tint to it. The thrust is blued out, and the turbo is toast. The next question is always "are you going to cover this under warranty" I do my best to help everyone out. But,,,,,,

Ok, there is the crash course dive to the dyno!!! hope you enjoyed it....

 

[Dsmkauai]

Thx for all the info I'll be putting my hx35 to use real soon!

 

[TimsTurbos]

Oh, forgot to address the home rebuild.
Well, here is an old post I wrote on my blog..
PART 1
So, you want to rebuild your own turbocharger? Well, if you insist on doing it yourself here are a few tip.

#1. Don't.... Ok now

#2. Don't watch the YouTube videos on how to rebuild your turbocharger from a kid who does not know how to rebuild a turbo. Especially if break cleaner is the main tool.

#3. Ok, now to the turbos. I'm not going to go into too much detail or share secret tricks but here are some pointer that might help.

First things first, mark the orientation of the 3 hsg's. There are 3 popular designs of turbos: 1) The BOLT TURBO! usually garret or earlier garret based models. Get yourself some penetrating oil and soak all the bolts for a day or two. One broken bolt in a Stainless Steel turbine can scrap the hsg. Unless you have a nice mill or lathe figure about $50 buck a bolt if you need that fixed. 2) The HYBRID TURBO! This usually has the snap ring on the cover and bolts on the turbine hsg. Holset likes this design a lot. These come apart ok. But, the turbine hsg probably looks like it has been sitting in water for a year. 3) Last but not least, THE STRAP-ON! These are held together with v-band clamps and snap rings. MHI likes this design These are usually pinned so they only go back together one way. These are one of the easier turbos to disassemble and reassemble.

Now that being said, figure out what turbo you want to buy for your project car. Don't be fooled by the guy selling you a turbo that just needs a rebuild. You're not getting a good deal. Give it the shake test: if it rattles, give it to the turbo gods. If you don't rebuild it yourself you are looking at about $350 (minimum) for a turbo in good shape. If the shop is doing it for a lot less, ask them good questions. "Where are your getting your kits?" "What balancers do you have?" "What is your cleaning process?" "How straight do you make the turbine shaft?" And if you are coming back for a warranty, ask, "Did too much oil pressure blow the seals out?" I love that one. It's hard to do a real quality job much under that price. A lot of cheap kit sellers are going to sell you crap fully knowing that your rebuilding skill aren't up to par and the turbo will fail anyway. And that's the truth. A quality kit is very important. Damn, I guess I forgot to explain how to rebuild a turbocharger! Ok, that will be in part 2.

 

[92AWDHX40]

Youll love the holset I cant wait till I get get mine installed and tuned on e 85.