67mm Holset Built by TurboLab of America

[Brandon Mau]

Here's a 2nd gear pull on my first run with the meth injection. I made no changes to my tune in this just to give you an idea of spool.

 

[1SIC1Gb]

Glad you're liking it, thanks for contributing !

So the log was a little confusing because its not showing 100% throttle until like 6800rpm.

What rpm are you generally hitting full boost ?

 

[JusMX141]

No airflow logs of Dave's 8.77 pass as we never had the laptop in the car that day- it was a do or die mission. Most airflow I saw on previous pulls at 36psi was 75-76 lb/min. I'm positive it was capable of more, and probably made more on the 8's run with the air temps being in the 40's....but that turbine housing is holding us back for sure.

New season = new turbo with new goals. We'll see what happens.

 

[1SIC1Gb]

That's awesome! I'm interested to see the housing difference . The 12cm2 from what I've read is like a .89 ar so I'd think it would flow pretty well. Pretty suprised the bep .70 is doing so well, though it is non divided .

 

[Brandon Mau]

The BEP does a good job for the size. The spool up is very similar to that of the standard 60mm. Once I turned it up to 30 P.S.I that's where I started seeing the higher flow.

 

[bastarddsm]

[QUOTE="1SIC1Gb, post: 153490043, member: ] The 12cm2 from what I've read is like a .89 ar so I'd think it would flow pretty well. Pretty suprised the bep .70 is doing so well, though it is non divided .[/QUOTE]

You have to remember that the divided effectively cuts the housing in half. It's gonna flow like a .5 or so. That big
Turnine might help, but I'd expect to see numbers about like a bolt on hx40 on this.

 

[1SIC1Gb]

I don't beleive that. The .89 ar I got off the Holset cummins boards . This housing is way bigger than my old .55 bep .

 

[JusMX141]

I don't beleive that.

Believe it. The divider takes up space and costs you valuable flow area.

While I don't think the restriction will be so great that it will limit you to as little as a .55 housing, I don't see it outperforming the .70 T3 BEP housing by much...if any. Comparing any two housings of the same a/r, the twin-scroll housing will always spool quicker (when set up properly) and the single-scroll housing will always flow more.

Not that there's anything wrong with your setup, it just seems like a lot of money spent on the manifold and wastegates to have it flow about the same or less than a BEP .70 housing and single-scroll manifold...unless spool is that crucial to you.

 

[jbeaton9292]

damn that compressor wheel is a monster in there

 

[1SIC1Gb]

Believe it. The divider takes up space and costs you valuable flow area.

While I don't think the restriction will be so great that it will limit you to as little as a .55 housing, I don't see it outperforming the .70 T3 BEP housing by much...if any. Comparing any two housings of the same a/r, the twin-scroll housing will always spool quicker (when set up properly) and the single-scroll housing will always flow more.

Not that there's anything wrong with your setup, it just seems like a lot of money spent on the manifold and wastegates to have it flow about the same or less than a BEP .70 housing and single-scroll manifold...unless spool is that crucial to you.

I had the 12cm2 housing already. I understand that the divider takes up room but saying it cuts it in half is not accurate. If need be I can get a 16cm2 holset housing but like I said being auto I want the lowest spool possible to an extent .

 

[bastarddsm]

Each exhaust pulse goes through a nozzle that is half the size of what it would be if it was open. Granted you have 2 times as long to get it through the nozzle. The problem is that at high flows it approaches the speed of sound and the flow-rate is capped, or the pressure increases massively to get it though the nozzle. It not takes a long time to get through and it gets backed up. It's not a linear function either. It goes to the ~1.4 power. So if you half the flow area, you end up at about 38% of the flow. It's not made up, look at any compressible flows text, look at any turbo design text. That 12cm is going to flow like a much smaller housing.

 

[1SIC1Gb]

I get that the divider takes up space but don't agree it's as much as you say.
((CM x 8) - 7) / 100 = a/r ratio
So some of the holset conversions would be
7 cm2 = 0.49 A/R
8 cm2 = 0.57 A/R
9 cm2 = 0.65 A/R
10 cm2 = 0.73 A/R
11 cm2 = 0.81 A/R
12 cm2 = 0.89 A/R
14 cm2 = 1.05 A/R
16 cm2 = 1.21 A/R
18 cm2 = 1.37 A/R
21 cm2 = 1.61 A/R

 

[lasthope05]

What surprises me is that they dont clip the turbine wheel when adding such a large compressor wheel. It would increase lag but will actually let the turbo make more power on the top end with less back pressure. You are already turbine limited and housing limited. Clipping the wheel is the next best option.

 

[CrackedDSM]

Believe it. The divider takes up space and costs you valuable flow area.

While I don't think the restriction will be so great that it will limit you to as little as a .55 housing, I don't see it outperforming the .70 T3 BEP housing by much...if any. Comparing any two housings of the same a/r, the twin-scroll housing will always spool quicker (when set up properly) and the single-scroll housing will always flow more.

Not that there's anything wrong with your setup, it just seems like a lot of money spent on the manifold and wastegates to have it flow about the same or less than a BEP .70 housing and single-scroll manifold...unless spool is that crucial to you.

On an Auto spool is definitely that crucial, especially for a street car at least for some of us. I mean yeah you can throw on .70 a/r T3 housing or a .80+ a/r open T4 housing and flow great but it's going to be a laggy PITA unless you go with a proper restall converter which is just going to flash up and slip everywhere. Some people can handle that or like it, tbh I personally would sacrifice it being a "massive flow but shitty spool" over "flows nice, spools great but doesn't flow as much as X". Mr. Peepers and Beansblacktsi cars come to mind. Great spool, awesome enjoyable powerband street cars, etc. It all boils down to basically, what do you prefer.



I hope to produce some real world data with the two turbos I'm going to be getting from you Justin. you know the ones.

 

[1SIC1Gb]

On an Auto spool is definitely that crucial, especially for a street car at least for some of us. I mean yeah you can throw on .70 a/r T3 housing or a .80+ a/r open T4 housing and flow great but it's going to be a laggy PITA unless you go with a proper restall converter which is just going to flash up and slip everywhere. Some people can handle that or like it, tbh I personally would sacrifice it being a "massive flow but sh**ty spool" over "flows nice, spools great but doesn't flow as much as X". Mr. Peepers and Beansblacktsi cars come to mind. Great spool, awesome enjoyable powerband street cars, etc. It all boils down to basically, what do you prefer.



I hope to produce some real world data with the two turbos I'm going to be getting from you Justin. you know the ones.

Well said . Beans is on a 16cm2 t4 but it spoils great being a true twin scroll setup

 

[CrackedDSM]

Beans' car is ridiculous. He gets up on the stock converter on his HX40 faster than I could get my 8cm2 16G w/ 272 cams. Both using the stock converter. Makes great power too. Absolutely one of my favorite cars twinscroll or not.

 

[goonie90gsx]

Its awesome to see more people pushing Holset turbos to the max and more! I love my billet hx40/.70 a/r housing so far. Threw a stock rod over the summer on my motor so im excited to make some good numbers/times this season.

 

[camfast]

I think it will be an interesting setup for sure and it depends on how fast you want to go. Eventually you will want to run faster times so perhaps going full T4 on nitrous will get you the best performance. What is your goal with this setup?

 

[1SIC1Gb]

Well being that it's a stalled auto, the hp will certainly not be as impressive. Like I said when I went 10.8 I dynoed 400/401. Not sure . I'd like to be in the 9s this year but who knows what's going to break. Damn dsms have gremlins .

I may go t4 but I really want to try to push the t3 platform as far as possible.

 

[1SIC1Gb]

I also have a dry shot to stall . Interested to see how this Bradco converter will do

 

[1SIC1Gb]

What surprises me is that they dont clip the turbine wheel when adding such a large compressor wheel. It would increase lag but will actually let the turbo make more power on the top end with less back pressure. You are already turbine limited and housing limited. Clipping the wheel is the next best option.

If I was trying to max the compressor that may be worth looking into but as you said it would increase lag. I'm trying to have this work well with the auto trans

 

[lasthope05]

If I was trying to max the compressor that may be worth looking into but as you said it would increase lag. I'm trying to have this work well with the auto trans

I understand your situation with spool, but, im talking about the other turbos they've built including the one Justin built. Its now known that the turbine wheel/housing is flow limited and to introduce a much larger compressor wheel is IMO somewhat useless on a turbo of this size. This isnt like a tdo5 20g. Sure you'll gain a bit more airflow, but you'll gain loads of back pressure(increased thrust load). Turbos of this size should be thinking about increasing mid/top end efficiency.

FP knew about this and clipped the td06h4 turbine wheel they used for the black in conjunction with the 3582 compressor wheel.

 

[CrackedDSM]

I understand your situation with spool, but, im talking about the other turbos they've built including the one Justin built. Its now known that the turbine wheel/housing is flow limited and to introduce a much larger compressor wheel is IMO somewhat useless on a turbo of this size. This isnt like a tdo5 20g. Sure you'll gain a bit more airflow, but you'll gain loads of back pressure(increased thrust load). Turbos of this size should be thinking about increasing mid/top end efficiency.

FP knew about this and clipped the td06h4 turbine wheel they used for the black in conjunction with the 3582 compressor wheel.

Very good point as well. Something to think about for the future.

 

[JusMX141]

FP knew about this and clipped the td06h4 turbine wheel they used for the black in conjunction with the 3582 compressor wheel.

Clipping a turbine works to squeak an additional 1-2 lb/min out of a turbine setup that may be at it's flow limit. I don't think there's a point where it would be "mandatory" unless you're using a horribly-undersized turbine housing a/r for your application.

The tradeoff is that it hurts turbine efficiency a bit in order to gain said flow. I've personally seen aggressively-clipped TD05H 20G's which initially spooled slower than the same turbo with a TD06H turbine. The boost recovery / transient response is still a bit quicker with the clipped TD05H, however...most-likely because the wheel is physically smaller. It's up to the user to decide if the additional lag is worth it or not.

Using the FP Black as an example of how well clipping works isn't wise...'tis a bit laggy, and I haven't seen a DSM-flanged Black live up to it's claimed 68 lb/min.

 

[Archer Fabrications]

This looks cool! I'm curious to know spool numbers. I just sold my hx40 and bought a 6466 ts 1.15. Thats too bad justin that you didn't get the gains you wanted, i didn't feel i was getting too much farther with mine at 67lb per min on a calibrated SD setup. At 38psi