HX40 19cm2 housing machined to fit HX52 with quick spool valve

[Boostdriven]

Hey guys,

I'm all about doing something different and custom so I decided to try this out and see how it will work. I still need to weld a 90 degree bend to my HX52 compressor cover so I have not tested it yet. Hopefully I'll have that done by the middle of next week.

Anyways, here is how this idea was born. Few months ago I was thinking of a way to make my HX40 with BEP .70 housing to spool a little quicker. Up on doing some research I decided instead of spending $600 dollars for a quick spool valve from Sound Performance I would just build my own. For that though I needed a divided housing. I had HX40 19cm2 but it seemed a little bit big so I picked up a used Garrett T4 divided .84 A/R. With some minor machining at my friends shop I got it to fit the HX40.

After I got all that done I took the car out for a test drive. The car didn't reach peak boost much faster then my BEP .70 maybe 200 rpms sooner but I did notice that the car pulled harder in the lower rpms. My boost curve instead of being a sharp ramp from 4500 to 5000 it was more of a gradual incline, I was getting higher boost at lower rpms.

Just recently I picked up used HX52 core to try out with my quick spool valve but because of the exhaust housing size it looked like it wouldn't fit in my car with out having to modify my manifold again. That's where HX40 housing comes in. I rebuilt the HX52 and started to figure out how I'm going to get this HX40 housing that uses bolts to fit HX52 which uses a V-band. After doing some brain storming I took that housing to my friends shop and machined it first to fit the HX52 wheel and cartridge. HX52 housing looks like uses a 3.5" V-band which I couldn't find so I figured I would make my own. For that I had to buy a piece of 3.5" schedule 40 pipe and a 4" V-band. I cut the flange part off the V-band which was 4" on the inside and slid it over the 3.5" piece of pipe which was 4" on the outside. That give me 3.5" on the inside which I needed for the HX52 cartridge. I welded that custom V-band to the housing and took it back to the shop for final machining. After all said and done I ended up with almost factory looking HX40 housing that fit HX52.

Like I said in the beginning its not bolted to the car yet because in order to fit that HX52 I have to weld a sharp 90 degree turn to the compressor cover to clear my front engine mount. My tig welder only welds steel so have to take it to a shop next week. I will keep you guys posted on this once I get it up and running.

 

[TJCTalon]

Wow man thats great work.

Your hoping for hx40 spool with the hx52?

 

[Boostdriven]

Wow man thats great work.

Your hoping for hx40 spool with the hx52?

I know HX40 housing being smaller will spool faster then the stock HX52 but I'm hoping with that quick spool valve I'll still get good power in the lower rpms.

 

[dsmcurse]

Hurry up with that 90* bend on the compressor cover! Im to excited to wait any longer. The suspense is killin me

 

[JusMX141]

Awesome work fabbing the v-band and all....but I'm assuming the HX52 housing was 16cm- just curious as to why you chose the HX40 housing despite the use of a spool valve unless there was some type of fitment issue due to the sheer bulk of the 52's factory housing.

 

[Boostdriven]

If my tig welder welded aluminum I would of had done yesterday I forgot to post few pics of the housing on the turbo, once I'm next to a computer again I'll put some up, I do most of my interneting off my phone.

 

[TJCTalon]

Post pictures of your whole set up if you can.

This is a cheap version of VGT. I wonder why more people havnt tried what your doing.

 

[Boostdriven]

Awesome work fabbing the v-band and all....but I'm assuming the HX52 housing was 16cm- just curious as to why you chose the HX40 housing despite the use of a spool valve unless there was some type of fitment issue due to the sheer bulk of the 52's factory housing.

Thanks man.
Part of the reason why I chose HX40 housing was because it looked like it would put the turbo further to the driver side giving me more room between compressor cover and front engine mount, but the main reason was because its smaller in a/r judging by physical appearance of it.

One other thing I liked about it was the fact that the chock point (throat) inside the housing just before the exhaust hits the wheel is larger in volume but the rest of the radius around the wheel is smaller which should help with spool up while not choking out the flow due to a larger throat.

 

[JusMX141]

Part of the reason why I chose HX40 housing was because it looked like it would put the turbo further to the driver side giving me more room between compressor cover and front engine mount, but the main reason was because its smaller in a/r judging by physical appearance of it.

I agree that the nozzle area of the HX40 housing definitely appears smaller, but I still think the flange angle of the HX52 housing is steeper toward the turbine than the HX40 housing which appears to face away from the turbine a little. It may be that the HX52 housing is just cast thicker in the nozzle area to support the weight of the turbo without cracking, hence it appears "larger" than it actually is.

To me it's still so hard comparing a/r ratios between turbo sizes...like how a T4 .68 housing is still physically bigger than a T3 .82 housing. SO confusing.

Kudos on the work, however...you've done what many have thought to be impossible. Anxiously awaiting results!

 

[Boostdriven]

I tried to measure the space between the inducer of the exhaust wheel and the outside diameter inside the housing as best as I could on the HX40 and it was smaller then the HX52 all the way around the wheel except at the very beginning where the exhaust first starts to go in to the wheel.

From my past experience of porting that entry point (bottom of the funnel inside the housing) on my BEP .70 I noticed about 2 psip of drive pressure drop while not sacrificing the spool up. I don't know what that particular point in the housing is called but if you look inside the housing from where it bolts up to the center cartridge and as u follow the exhaust stream as it wraps around the wheel eventually it hits the main stream again, well I ported that section of the housing raising it about 3/4" further up in the the funnel while porting out the bottom of the funnel larger. This allowed the exhaust flow to hit the wheel from a larger diameter at the bottom of the funnel. I have few pics of that on my phone but I can't post them from it. I'll try to put some up when I'm next to a computer.
Looking at that point inside the HX40 and HX52, HX40 looks larger while the rest of the housing is smaller.

Post pictures of your whole set up if you can.

This is a cheap version of VGT. I wonder why more people havnt tried what your doing.

I wouldn't say its a cheap version of VGT but I know what you're saying. It's cheap for me cause I'm doing all the work myself and the only cost is material but if I was to add up the hours I spent doing all this and had to pay someone to do it, I would probably have to sell my kidney to pay for it

I always liked to do something different. Sometime ago I started a thread on here about a compounding turbo set up plummed backwards to see what others thought about it, well I ended up building it. I never got a chance to test its full potential due to the smoking HX52 I had at the time, it needed a rebuild. I used my HX40 as primary and HX52 as secondary. HX40 blew air in the HX52. The exhaust side was plummed the same which is how compound set up is usually ran.

The few times I drove the car I couldn't get it to build more then 28-30 psi and as the motor got in to the higher rpms the boost would drop few psi. I couldn't play with it much because my HX52 smoked and I thought that the whole things was just a bad idea. I ended up taking it a apart and since my friend was looking for a turbo for his 2jz I sold him the HX52, after I rebuilt it of course

What I didn't realize at that time was that the air filter I was using was causing a massive restriction. I used a 8" HKS filter but because the original filter membrane was bad I replaced it with filter that was used on a V8 marine engine. It was a flat piece of sponge like material which was designed to lay flat. I cut a nice circle out of that piece and made it fit that 8" coned HKS filter. I don't realize that when I folded that filter to make a cone it closed off the pours on the inside of that sponge and as the air pressure was moving through that filter it was closing it off even more. I found this out because when I put my car back to the original single turbo set up using the HX40 I used that same filter. I took the car out for a drive and to my surprise car wouldn't build more then 27-28 psi and boost would drop dramatically at higher rpms. Changed back to my old filter and the problem was solved.

I used a map sensor to log pressure between the two turbos. According to my log the boost pressure between the two turbos and the intake manifold would stay the same to about 10-13 psi and as the boost in the manifold got higher the pressure between the turbos started to drop. I can't remember now but I don't thing my map sensor ever logged vacuum between the turbos but I know it was getting low like 2-4 psi.

I look back now and kind of wish that I had more patience then and didn't sell the HX52 and the custom manifold that I built to fit those two monsters in there. Kind of sucks that I found out after I sold all my stuff that the filter was the cause of it not working. I took pictures of the whole work progress but my stupid memory chip took a shit so I lost all those pics that's why I never followed up on my original "compound turbo plummed backwards" thread. Who knows maybe one day I'll end up trying it out again.

 

[fosforito95]

cant wait for you to post some results looks interesting.

 

[LandSpeed-DSM]

That was quite an undertaking. Curious to see how this works out for you. I would really like to have other options to test out on my HX52 and see differences in pre/post turbine EGTs, Boost-to-Drive pressure ratios, VE, and power production as I already have the sensors in place to take that data.

As far as the reversed series turbos attempt.. perhaps you can address for some of us why you thought limiting the flow of the larger compressor to the inlet size of the smaller compressor would have been advantageous?

That's basically running a restrictor, like you would in WRC/NASA rally.. which is not especially good for the turbo in terms of longevity and certainly not from a performance aspect. Additionally the size difference between an HX40 and HX52, while considerable.. would not be a good match for a compound setup.

A 3076R, S200sx or HX35 would have been a much better pairing, especially when plumbed in the "traditional" manner.

What was your hypothesis?

 

[Boostdriven]

That was quite an undertaking. Curious to see how this works out for you. I would really like to have other options to test out on my HX52 and see differences in pre/post turbine EGTs, Boost-to-Drive pressure ratios, VE, and power production as I already have the sensors in place to take that data.

As far as the reversed series turbos attempt.. perhaps you can address for some of us why you thought limiting the flow of the larger compressor to the inlet size of the smaller compressor would have been advantageous?

That's basically running a restrictor, like you would in WRC/NASA rally.. which is not especially good for the turbo in terms of longevity and certainly not from a performance aspect. Additionally the size difference between an HX40 and HX52, while considerable.. would not be a good match for a compound setup.

A 3076R, S200sx or HX35 would have been a much better pairing, especially when plumbed in the "traditional" manner.

What was your hypothesis?

My understanding of a traditional compound set up is to be able to run more boost then either of the turbos could supper by themselves. My idea was to still run lower boost like 34-36 psi not 45-50 psi and still get the spool up of a smaller turbo and the flow of the bigger one. I used HX40 because that's what I already had. Those few times I drove the car it spooled up just as fast as the HX40 alone maybe a little sooner.

Before I built this project I called around and asked few people that have done a traditional compound set up. One in particular was Boostlogic, they have done a compound turbo on a supra, when I asked a guy there how it works and what he thought about it, he said that they don't build them anymore and when I asked why he said that it wasn't efficient at lower boost levels. In order to get it to work as intended you would have to run higher boost, which is the point of a compound set up. I didn't plan on running more boost then 34-36 psi, I run pump gas and water/meth.

My theory was that if I can keep positive pressure between the two turbos all the way to red line that would mean that the big turbo is taking air from a space that has higher pressure then atmospheric pressure, which not only would allowed the big turbo to function as if it was alone but more efficient because it has positive pressure before the compressor.

Essentially it proved to be that way but like I said before because of the smoky HX52 I didn't get a chance to play with it and work the bugs out of it. I tore it apart just to find out later about the filter problem I can't say right now that it worked the way I was intending it to because I never got to test its full potential but I can say that the little results I got out of it gives me enough reason to maybe do it again sometime.

 

[Cdc1221]

While not entirely related to the op, i have to wonder if ducting the comp inlet to say a 10-12" airdam in front of the car with a matching high volume fan blowing into it might help with spoolup, especially with a bigger turbo...

While it wouldnt increase pressure to the comp inlet, it would increase available air for the turbo to pull in, in theory allowing it to spool sooner

 

[Boostdriven]

Another idea that I was kind of entertaining was to use a vortech supercharger and put in the place where the power steering pump goes, have the filter sit on the supercharger and blow the air in to a big turbo. Of course the biggest problem would be making brackets to mount it and figuring out the pulley system to drive it. A guy would probably have to put an electric water pump and relocated the alternator where the ac pump goes. Not only would you have instant boost but you would have full power of a big turbo. If I was building complete custom drag car that's what I would be looking in to.

 

[Cdc1221]

Not really. You would still only get whatever airflow the supercharger could put out. Itd would be more beneficial in this case to just use the supercharger and lose the exhaust restriction of the turbo

 

[Boostdriven]

Why wouldn't it work, think about it. A turbo alone is only supplied by the atmospheric pressure which is like 14.7 psia. A car turbo or not will make more power at sea level then at 5000 feet above sea level. If you take a big turbo and supply positive pressure 14.7psia+x psi it will already make that turbo more efficient. So if a supercharger is supplying 5 psi of boost through out the rpm range that turbo will make more power then if it was alone.

If you look at the fuel pump flow chart, the less fuel pressure it has the more fuel it can displace. Same goes for a turbo or supercharger. If you take a supercharger let's say spinning at 40k rpms producing 10psi it will displace X volume of air but if you take that same supercharger and blow it in to open air at same 40k rpms it will displace a lot more air volume because there is no pressure holding back the flow. So if let's say a supercharger is making 15 psi at 2500 engine rpms that will not change until the turbo starts to consume more boost then it can supply. The boost pressure of a supercharger will start to drop but the rpms of the supercharger will not change it will increase as the engine rpm increases. As the boost pressure of the supercharger decreases the load of it on the engine decreases therefore the power loss should decrease as well.

Of course you couldn't just take a turbo like HX80 and feed it with a small supercharger, things would have to be matched accordingly. A supercharger that is capable of supplying 10-15 psi on a big V8 engine will produce a lot more boost on a small engine like a 2L 4 cylinder because air consumption would be a lot less. It doesn't matter to it what spins it, a big V8 or a small 4 cylinder because its all based off of engine rpm. So if you take a supercharger that's making 15psi at 2500 engine rpm and by red line its only capable of supplying 5 psi that would still be better then a turbo alone. Yes there will be some power loss due to a drag of a supercharger on the engine but I think the power an engine would make at lower rpms and the spool time of a big turbo would make the loss of HP due to supercharger drag insignificant.

In theory it would be like driving your car at the bottom of the ocean

If anyone has some input on this please post your thoughts, this is just my thinking.

I'm hoping to have that 90* bend welded to my compressor cover today, if I do I might be doing some testing with that HX52, I'll keep u guys posted.

 

[turbo23]

FWIW I don't know why boost logics had issues with there compound setup. Mine works flawlessly at 37psi and I expect it to work even better at 50-60 psi. My powerband everywhere was ridiculous. I was able to make 30 psi on the stock stall converter and no nitrous.

Edit: I am on Tylers account. This is Viperlp01

 

[Cdc1221]

The whole idea behind compounding chargers is to reduce lag time with a big, high volume charger by blowing a smaller less laggy charger. Since turbos work off engine load moreso than actual rpm, they tend to be peakier whereas superchargers have a more linear power curve that increases with rpm. A supercharger that is too big may never achieve positive pressure. The only way to benefit from using a supercharger compounded with a turbo on a smaller displacement engine would be to use a supercharger sized to make around 350 hp alone, and feed it with a much larger turbo. This would give you a more linear power curve. Feeding a big charger via a smaller one would in effect only give you the air volume of the small one with the lag of the big one

 

[Boostdriven]

Feeding a big charger via a smaller one would in effect only give you the air volume of the small one with the lag of the big one

Explain to me why you think 14.7psia + let's say 5psi figuratively speaking equaling 19.7 psia before the big turbo would be a restriction? That's one question. Another question why would you have the lag of a big turbo if a supercharger would already produce let's say 15 psi at 2500 rpms almost instantly as you floor the throttle?

I built that set up already using two turbos, I was getting 28 psi by 5000 rpms in the manifold and about 7-9 psi between the turbos, so it wasn't my HX40 that was making 28 psi it was the HX52 or more like a combination of both.

What spools the turbo? Exhaust flow, what increases exhaust flow? Rpm for one but also air volume going in to the engine. If you can have 15 psi at 2500 rpms that's already that much more air flow going out of the engine therefore more flow to spool the big turbo. So technically that big turbo would spool even faster then if it was working alone trying to generate its own boost hence more exhaust flow.

I'm might be wrong on this but I think peak HP on a compound set up running HX35 and HX52 in a traditional set up at 25 psi would not be much higher then just a HX35 alone. You will get a better power curve but not a lot of peak HP. The whole point of a compound set up is to be able to run high boost efficiently, not only do you get better boost response with a smaller turbo but between the two you can run 50-60 psi of boost, that was never my goal. I'm pretty sure running a small turbo in to the big one will not give you the ability to run 50-60 psi of boost but that's not what I was looking for anyways. If I was looking to run that high of a boost then hands down I would have built it the traditional way because that's how it works.

My whole idea was to run about 35 psi of boost on a big turbo while getting the spool of a smaller one. If I had HX35 at that time I would have used it instead of the HX40. As far as I can tell right now my set up worked because I was getting boost just as fast as an HX40 alone but since I had that shitty filter the flow of air in to the whole system was choked off by it.

 

[Cdc1221]

I give you props for building a compound setup, and the housing looks great by the way.

I don't really know the exact airflow numbers of these turbos, so lets just say a hx40 flows 60 lbs per min, and an hx52 flows 75 lbs per min. now, to get it out of the way, when compounding them where the 40 flows into the inlet of the 52, you cannot get anymore flow than the 40s wheel can produce. so the hx52 is in effect just an exhaust restriction slowing down the exhaust before it gets to the hx40, slowing spool on it, while not producing any extra airflow.

your supercharger idea is the same way. it will run out of steam and the bigger turbo will start pulling a vacuum in between its inlet and the superchargers outlet. now, if you were to reverse this, and push the air into the supercharger, you will keep pressurized air going to it for it to further compress into the engine.

or you could run them sequentially, so that both supercharger and turbo are feeding into the intake manifold, so that you could get low rpm boost, and keep it to redline when the turbo starts spooling. if this is in fact what you meant, I apologize for the argument

 

[Boostdriven]

I don't take it as you are arguing with me, you have your opinion and you are entitled to it.

Running supercharger and turbo sequentially would required some kind of a check valve system because before the turbo would build boost the supercharger would push air out through the turbo and the other way around, once the turbo started to build more boost then a supercharger it would push air out of it.

The whole flow numbers of each turbo are rated at certain boost levels and I know its above 30 psi. What I was saying that if you take that HX40 and still run the same amount of exhaust through it, still spinning it at the same rpm as you would to generate 30 psi but instead blow it in to open air, in this case a bigger turbo that's consuming the boost, it would displace a larger volume of air (cfm) then if it was pushing against 30 psi of pressure. It would simply be moving air from one end to the other.

 

[dsmcurse]

Says a base model lazer with a 16g..... I rode in that compound. The turbo was turbocharged. Okay, now re-read that and really think about it. The BIG turbo wasnt driven by a engine alone, the big turbo was boosted from a turbo that was drivin off of a badass motor build. Throw all the scientific big word mummbo-jumbo out the window and think of it in simple terms. One solid sick-ass motor, two respectivly sized turbos, linked to gether so that the big money maker turbo is TURBOCHARGED. Nuff said...

 

[spoonman]

*A compound turbocharger system employs a small turbo that is capable of with standing a high PR that is driven by the engines exhuast gas. Down stream of the out let of the smaller turbine housing is our larger secondary turbocharger, the exiting exhaust gas (which is cooler, very turbulent, and has a pressure drop) enters the turbine housing of the secondary turbo, and exits the outlet to a down pipe and into the atmosphere.

The compressor side on the other hand reacts as follows. The primary turbo "spools" first and draws air through the secondary (larger) compressor, which in turn has a positive effect of "spooling" the larger turbo slightly faster. As your engine speed picks up and you are flowing greater lbs/min. The primary turbo would (if alone) reach its limit as to what it can flow.
Although with the secondaryturbo supplying compressed air at a high PR into the smaller primary compressor, which in turn re compresses this air and gives you a much denser charge.



The higher rate of flow is from the secondary turbo, the higher multiplied PR is an effect of compound charging. It creates a large amount of heat.

So why not just run one big turbo? Faster spool of the smaller turbo and a more linear torque curve. The only downside is greatly increasing charge temp.



Shop air compressors that are "2 stage" are compound compressors. They also is it in refrigeration.

 

[spoonman]

Other problems with "typical" compound charging are much higher pressures on the exhuast side. But luckily the turbine adds restriction and does not compress. So the charge side is theoretically always higher. That is a huge positive for the engines VE and can reduce pumping losses.