I've had a lot of questions about the turbo I'm running, and I didn't want to get another thread too off topic, so I'll put some info up here. Just for reference, I have the 6 blade HX40 with a 19cm T4 holset housing. A large majority of the info I have I gleaned from the DSM forums which is the is 90's american version of the Evo. They all have 4G63's in Mitsu Ecliplses and Eagle Talons, and most of the guys on this site have AWD versions. Anyways, I'll post up some general info they have on holsets and get into more specifics later if anybody expresses interest. Also keep in mind most of this info is geared towards 4g63 applications, so they talk about BEP (Bullseye Performance) housings Again, I don't want to take credit for somebody else's work, so here is some info from THIER page.

Summary provided by wiseman, Dsm-onster:
HX35:

The 8blade hx35 has a 56mm compressor inducer. This is found on 1995-1998 cummins manual pickups. The compressor flows 52 lb/min according to the compressor map. The bolton BEP housing (0.55 a/r) is enough to push the limit of the compressor. There's several 500whp 8blade hx35 cars out there with the bolt on housing. It reaches 20+psi by 3500rpms in 3rd with 272 cams. Smaller cams would equal a faster spool speed in most cases.

The 7blade hx35 has a 56mm compressor inducer. This is found on the 1999-2002 cummins manual pickups. The compressor flows 60lb/min according to the compressor map and logged results from a member here. The bolton BEP housing with the hx35 turbine wheel do not SEAM to have enough flow to really reach the potential of 60lb/min. But many have logged over 50lb/min so far and seen 500whp. The stock hx35 12cm^2 twinscroll turbine housing is a t3 flange housing. This mated to a NON-divided runner manifold has produced a 132mph trap speed with a full weight 1g AWD. This is about 600whp. So the flow is there with the stock housing if you use a non-divided manifold. The spool speed of the 7blade hx35 is similar to the 8blade hx35 with 20+ psi by 3500rpms in the bolton housing and by 4000rpms with the stock housing with a non-divided manifold.

HY35:

The hy35 has a smaller turbine wheel than the hx35. And, it has a turbine housing connection that does not allow for a bolton housing to be used. It does not have a divided housing so any t3 manifold can be used effectively with this turbo. It has the same compressor as the 7blade hx35. We don't know if te hy35 turbine wheel and housing is enough to reache the 60lb/min potential of the 56mm 7blade compressor. Some one try it out already!!! It should at least be a faster spooling viable option to the full t3/t4 50-trim.

H1C/WH1C:

In 1994, there was the Wh1c which has pretty much the identical compressor as the hx35 but with a Vband compressor cover. The turbine wheel is the same. It will bolt into the BEP bolton hx35 turbine housing. It has 4 bolts at the housing instead of 6. So you will need to buy 2 more bolts and use 6 washers cut to make a flat side. Honestly, I just used bolts that were cut a little short and the bolt head was wide enough to pull the chra to the turbine housing. No sealing issues. Since the Wh1c is for all practical purposes an 8blade hx35 the spool and flow is the same too.

I have the big h1c. It comes on the INTERCOOLED 1991-1993 cummins pickups. It has the webbing for MWE but no groove cut like the hx35/wh1c has. This turbo I term the big h1c because it has a 54mm compressor inducer and same exducer than the 8blade hx35/Wh1c. The other h1c is the small h1c found on the NON-intercooled cummins pickups. This has a 50mm inducer but only 7blades and has no webbing for MWE. Less blades helps flow, but so does a larger inducer diameter. The most whp ever recorded on a gas 4cylinder with the small h1c was done on a KA24 nissan: 411whp. Since the big h1c has a 4mm larger inducer and the same turbine wheel as the hx35, it is safe to say that it flows enough for between 411whp and 500whp. The diesel sources state that it flows SLIGHTLY less than the early hx35. So 4lb/min less than the 8blade hx35 puts the flow of the big h1c at 48-49lb/min right where a 50-trim or 20g is. The small bep housing is all that's needed to get the most from the compressor and the spool speed is 20+psi by 3500rpms.

HX35-40 hybrid:

Keeping the long tradition of the marriage of sportcompact and hybrid turbos, there is the hx35 turbine and the hx40 compressor. It is strongly recommended to use the large bep turbine housing or the stock hx35 turbine housing with an non-divided t3 manifold for this turbo. The small bep housing around a t31 size hx35 turbine wheel is probably not enough to merit any of the hx40 compressor wheel upgrades. 20+ psi by 4000rpms can be seen in the hx35/40 with the hx35 12cm^2 turbine housing with a non-divided t3 manifold. With the large bep housing, spool times are to be determined. But likely similar.

HX40:

The 8blade hx40 has a 58mm inducer and flows about the same as a 60-1 (around 60lb/min) with ALOT better high boost efficiency and spool speed. It is the most common hx40 out there. The small bep housing with the hx40 turbine wheel is plenty to reach the full potential of the 60lb/min 8blade hx40 compressor. 20+ psi by 4100rpms with 272s.

The 7 and 6 blade hx40 is called the super40 and has the 60mm compressor inducer. This compressor flows around 69lb/min. You can get this wheel in billet style (think HTA). The non-billet wheel spools as fast as the 8blade hx40 in the bolton bep housing and has done 653whp at 40psi per the holset results only thread. Billet should spool even faster. The t3 .70 a/r BEP housing slows spool about 400rpms. But reports show a significant gain in flow per psi. So expect more power at lower boost with that turbine housing.

H1E/WH1E:

The Wh1e is like it's little brother the Wh1c. It mirrors the hx40 8blade in every way except that it has a v-band compressor cover and a 4bolt chra-turbinehousing pattern. It will consequently bolt into the hx40 bep bolton turbine housing and this is plenty of flow to max out its 60lb/min compressor.

The h1e is like it's little brother the h1c. There are different size compressors. . . BUT there are also different size turbine wheels too. Check measurements before buying this turbo if you plan on running a BEP turbine housing. There are lower flowing compressors than the 58mm 8blade that are out there. So this turbo may not flow any more than an hx35 if get the wrong one. You need at least a 58mm compressor inducer for this to be a worthwhile turbo vs the proven hx35 or 8blade hx40.

HX52:

This is a big sucker. It is commonly found on the Volvo Semis and usually has a billet compressor wheel. It flows 88lb/min. There is no bolt on housing for it. If you want a bolton housing for this turbo, then you don't want this turbo. In fact if you want a t3 flange turbine housing for this turbo, then you don't want this turbo. You DO want this turbo if you're looking at a gt4294r or gt4202r. The turbine inlet is slightly different than a t4 bolt pattern. You can still get the t4 manifold to work just fine by enlarging the bolt holes.

Misc.:

• Holset's don't spool slow. They spool faster than their garrett or mitsubishi counterparts. Diesel exhaust is cold and slow moving.

• The holset turbine wheel is a work of art. It has been shown to flow very well in a very small turbine housing. For example the hx40 turbine wheel in the small .55 ar bep bolton housing flows as much as a garrett gt35r turbine wheel in a larger .63 ar garrett t3 turbine housing. The hx40 with this configuration spools about 500rpms faster! You can upgrade to the .70 a/r BEP t3 turbine housing and have the same or slightly faster spool speed as the above gt35r with ALOT more flow per psi and consequently more horsepower per psi. This makes for VERY good pumpgas numbers.

• Holset patented map width enhancement. They do not have extended tip technology, but there compressors show more efficiency than their garrett or mitsubishi counterpart.

• They have superback technology witch leads to VERY, VERY durable compressors. The are designed to be overworked and underpaid.

• There are discrepancies all over the web concerning the compressor maps. Take what you hear/read with a grain of salt and a shot of tequila, and the worm.

• The holset is fine with stock 4g63 oil pressure from the oil filter housing. If you have no b shafts, you'll need a restrictor. The drain line is a garret bolt pattern. The feed line is different for different turbos.l

Register on the forums for fewer ads.

**Almost forgot the whole point of these turbos. They go new shipped on american ebay for under $500

If I wanted to make 550hp with an RB25 motor that is built for it, mainly for track work so spool/lag kept as low as possible, which turbo would do the job?

http://idforums.net/index.php?showtopic=33299&hl=holset
Something I found haha.

At the wheels or motor hp? You could make 550hp at the motor with the 7 blade HX35 and I bet it would be at 1 bar by 3.5k rpm or less. If you want that kind of power at the wheels, you need a 6/7 blade HX40. Mine is making 1 bar by 4.2k rpm in third with a 19cm housing and I'm making that kind of power.



That link has a good write up that I used as info when I was first researching these turbos. It focuses mostly on the smaller holsets, so it's especially good if you want to do togue or something like that.

Hi CJ , there has been a trend towards some Holset and Borgwarner turbo bits mainly in the US for a year or so now .

At least one American performance house is hinted to be using Holset or BW compressor wheels in Garrett BB cartridges to try and give them a little better response and performance .

The thing to remember is that most of these Holset and BW units are designed to be diesel engine turbochargers and that alters their design brief and material specefications .
Now because of the fuel they burn diseasel engines almost always have lower EGT's than petrol engines , because of the significantly higher static compression ratios and generally throttle less inlet manifolds they have much higher dynamic CR's and so make more torque for their capacity than a similar sized petrol engine - particularly at low revs .

The lower EGT's mean the manufacturers can use more mundane (cheaper easier to work with) materials in diesel engine turbos (turbine and it's housing) and this make them considerably cheaper to produce and sell .

Not everyone will agree with me here but I think the real answer to the spool/turbine lag issue is twin scroll turbine housings , you eventually reach a point with an open housing turbocharger where you have to err one way or the other for earlyish turbine response or low restriction further up the engines rev range .
I think the healthy sized turbine and housing used with a just adequately size compressor gives an acceptable all round result on petrol engines provided the frame size used is not way too big .

Also BTW other manufacturers sell bigish diesel engine plain bearing turbos though I haven't noticed any new at $500 dollars .

Ball bearing center sections are nice but if you can build a plain bearing unit and combine it with an engine that has a low restriction hot side you don't get the massive thrust loadings from the hot side of the turbocharger . It's these loadings (and overheat/overspeed) that generally destroys the thrust plate bearings in bush or plain bearing turbos because of the massive exhaust manifold pressure vs inlet manifold pressure .

Compact high speed petrol engine BB turbos are compact because they use big trim low innertia low blade count wheels - at higher shaft speeds .
They will be more expensive but they can be more compact and lighter in weight until you get to large frame sizes .

With a Mitsy 4G63T I'd be looking into Evo Lancer turbo territory , rather exy but I think one well known mob is making manifolds to fit the Garrett TS GT3071R/GT3076R BB turbo on E 4-9 .
Maybe even a hybrid Evo 10 TD05 with the big 12cm TS housing would work well .

A .

So lets say I'm looking for good 400-450 flywheel hp. Responsive.
What Holset turbo should I look into ?

What about the smaller frame ones ? Like for under 400hp ?

we used to buy holset turbos from a machinery wreckers a lot of combine haversters had them fitted we would buy them for under a hundred bucks and fit them to holden red motors and falcon motors ir was pot luck if you got the right size tho

some of them went like the clappers im talking back in the early 80's when there wasent much of a selection in turbo's like there is now

is there any chance of doing up a chart and refering what turbos are suitable to what engines and what horse power these turbos are rated for would a h1c turbo be suitable for an rb25 looking to run around 380-400 rwhp would this turbo be suitable i noticed alot of the ka24 engines in america run these turbos to get these sort of numbers would this be the same story for a rb25 ???
link too ebay wh1c turbo 1

As for the "how much hp" or "which turbo for X hp", it's tough because holsets have such a wide range of compressors for each turbo, but in general at "sane" boost levels less than 2 bar;

HY35- more than 450hp at the motor, but not many people have messed with them. They have a smaller exhuast wheel than the HX35 with the same compressor, and a smaller a/r SINGLE scroll ex housing. The few people I have heard running them say the have REALLY fast spool--like over 1 bar by less than 3k rpm on a 2.0L 4 banger.

HX35- 450hp to 550hp at the motor depending on the compressor blade count. Spool on a RB25 would be less than 3.5k rpm. The DSM guys say it'll make a lot more than that, but I just have a tough time believing it. They are ripping off 132mph trap speeds with them though, so I guess it's possible. They do crazy stuff though like running 2.1 bar on C16 or water/methenal injection.

HX35/40 hybrid- This was my first venture with holsets. I was making 1 bar by 3.5 and 1.5 bar by around 3.9k rpm in 3 IIRC. Keep in mind though, that's with cams, RB26 intake and ITB's (short runners), and no VCT. I've got a vid I'll link up later. Stock everything would spool up a bit quicker I think. I had the smaller 8 blade HX 40 compressor mated to a HX35 ex wheel/housing. I would spike it to 1.6, but it would fall off on the top end to around 1.4 bar. I was making mid 500's at the motor with it. This is the one I pegged out a Z32 MAF with.

HX40- Capable of around 500-600rwhp depending on the compressor. The smaller 8 blade is what I had making mid 500's at the motor. The 6 or 7 blade compressor is the bigger one and it's a 69lb/min compressor and it's what I have now. With a 19cm housing, I make 1 bar by 4.1k rpm in third gear and 1.5 by less than 4.5k rpm.

HX52- This thing is huge. Like 104mm exducer and 72mm inducer IIRC. My buddy has one on his RB25 and makes 1 bar by under 5k rpm with big cams and a custom intake and a 16cm ex housing. He stopped turning up the boost around 1.4 bar because he was over 95% on 740cc injectors at a/f's in the high 11's. Make of that what you will, but that thing scares the CRAP out of me. It's in a S14 sylvia BTW. He will pull hard on stripped out, T88, RB26 S13's at our local drag spot. He's currently looking for a tripple plate and 1000cc injectors.

Discopotato-- Thanks for the input and I want to reply in depth to some of the issues you brought up, but I want to take the time to respond to everything in detail, so it's going to have to wait until I get home. Quick summary though, these things are BEEFY and while I don't know the metal composition, I can assure you running them in a gasoline applicaiton will not be a problem (except in the case of the newer ones with variable a/r ex housing--which people have started using in gasoline engines already, but I have my doubts about thier longevity).

The other big thing I wanted to bring up is it sounds like you believe these turbo's to be slow spooling due to lack of BB CHRA's. These are bush bearing, but they outspool there respective sized Garret BB counterparts. They are indeed twin scroll (split pulse) with the exception of the HY and some other strange one off applications of HX40's. The wheel design is MUCH better than Garret's design and as I'm sure you know, wheel design is much more a factor in spool time than whether or not a CHRA is BB. Now combining the two like you mentioned would indeed make an incredibly quick spooling turbo, but it would defeat what is, in my opinion, the best part about these turbo's. Low price. They are so cheap not from the factory, but surplus on ebay. They come in a miriad of Semi-trucks and busses, and make thier way to ebay all the time, never being installed. I got my HX40 used for $200, and my buddy got his HX52 new from ebay for $450 plus shipping to Okinawa. I've got many more expamples, but get on american ebay and search "holset". You'll see.

The one downside you brought up I can agree with is the frame/overall size and weight of these things. They are BIG. Compare my HX40 next to a GT35r and it dwarfs the garrett. It does as I mentioned however, outspool and outflow the Garrett.

OK, sorry, that wasn't so brief

Here's a couple of vid of my old HX35/40 hybrid if anybody cares to see.

http://videos.streetfire.net/video/R32-Sky...-car_143698.htm

http://videos.streetfire.net/video/Spoolin...id-a_147457.htm

http://videos.streetfire.net/video/Skyline...-ish_164772.htm

I was just typing about how I saw some vids of an rb25 r32 in japan on nico forums. And here are the vids LOL.
Nice car, nice spool!

if i was looking for about 230 kw's at the wheels, which turbo should i go with? and where can i get them from?


oh and i drive an r33 gtst

Your best bet for response at that power level would be an hy35. Although probably not the most efficient setup, as the Hy only has a small 9cm housing. It will spool very fast and make the power you want, however, taking advantage of the larger 12cm divided housing will make the setup more efficient, slightly laggier, but with less restriction on the top end.

I just had a 6boost divided manifold made, and I'm mating it to an 8 blade HX35w with a 12cm divided housing. This is on an rb20det with 256 cams. Just looking for 350whp. I'll post my results here when my car's on the road, to give more some real life results/examples.

Edit: oh yeah. Find a turbo on ebay, I got my 8 blade Hx35w for $450 shipped, remanufactured.

Just some more info for fodder. I went out tonight on the way home from work and got some spool times.

3rd gear - .5 bar by 3.5k rpm
- 1.0 bar by 4.2k rpm

4th gear - .5 bar by 3.2k rpm
- 1.0 bar by 3.9 rpm

hey mate, what would you reccommend for roughly 280-320rwkw in an r33gtst?
i want to have some good response tho , thanks alot.

300rwkw = 400rwhp'ish, right? HX35 would be the way to go. That thing would probably get you 1 bar by less than 3.5krpm--maybe considerably less.

Fandango--I'm not very familiar with the turbo's smaller than the HX35. The HY35 is a single scroll version of the HX35 with a smaller ex wheel and small ex housing a/r. It supossed to be the version they put on automatic diesel pick ups to help with spool, so it should come on sooner. They do make HX25's also, but I know nothing about them. I wouldn't think that kind of power would be much more than what you could do with the stock turbo though. Is it worth it to spend a lot of money putting on a turbo kit for only 30-40hp? What kind of spool times are you wanting and what will you do with the car? You might want something like a HKS?2535 for that kind of power and it bolts right on.

[quote name='Cjmartz2k' date='10 Dec 2008, 03:43 PM' post='4309975']
300rwkw = 400rwhp'ish, right? HX35 would be the way to go. That thing would probably get you 1 bar by less than 3.5krpm--maybe considerably less.

Thanks Chris, i have read there is alot of work that goes into fitting these turbos, due to them not being made to car specs.

from what i can think of for it to fit and rb25det would be, custom dump, intercooler piping, oil lines and probably squezzing it in.
i would put it on a standards manifold as it is t3 (i think), there internaly gates so that should be ok.

is there anything else i have forgot?
also i have found a few hx35w's on ebay, is the w anything diffrent?
thanks heaps
Gezza

This is the first I have ever heard of Holset turbo's and let me tell you I am going crazy over this sh!t. lol

If I only I was more familiar with turbines when I ran V8's

Check this out. lol

http://cgi.ebay.com.au/massive-turbo-HOLSE...A1%7C240%3A1318

I think it'll be a tough squeeze trying to fit one of them down on the side of the motor, but I'm not going to discourage you from trying! I had one of the old bottom mount HKS manifolds when I ran my HX35/40 hybrid on my R32. We needed to notch the crossmember to clear the compressor cover on it. Remember, these things are not as compact size wise as their garrett counterparts. The W means wastegate, but I can't remeber if that means it needs an external, or has an internal. I haven't heard of to many people using the internal gates on them. You would have to port the piss out of it at the very least, but maybe people just don't do it because it's so easy to go external wastegate.

We don't have many bolt on options for a reasonable price here on Okinawa, so I just assume that when people talk about putting on a decent sized turbo, they are going to be planning for a whole setup, i.e; manifold (I prefer top mount for the room), external wastegate, FMIC with piping, custom dump, etc. I'll try and post up a picture I have of the size of these things when I get home.