Torn between my Borg Warner S366 and my Holset HX40

[Tippy]

I am very happy with the BW S366, but wish I could get part-throttle, cruising boost, that makes an engine feel much torquier around town. When I went to this beast, I never sold the HX40. Now, I don't feel this S366 is laggy; it's certainly not for its gargantuan size, but it is not as quick as the HX40.

Little background:

I machined a .84 AR divided T4 housing coming from a 1.00 divided (a little laggy - spooled as quick as the S366 in out of box config) on the HX40, had great low end torque, and hit nearly 129 MPH in the quarter mile. Super awesome!

But, would hear the turbo whistle diminish, or go away at higher RPM, possibly closing in on the choke line of the compressor. Not good. Scared I was over revving the poor little 58mm wheel.

What do I do? I buy a much bigger turbo that is....

In comes the beastly BW S366. This thing is a monster in size, capable of 830hp with its moderately sized 66mm compressor wheel and unbelievably sized 73mm turbine wheel.

This turbo has actually made a little more boost in 1st than the HX40. Unreal. Been in love.

It was slightly laggier than the HX40, but come on, the entire HX40 could fit inside the turbine housing of the S366. HEHE. It spools unbelievably quick for its turbine size.

Like, defies physics quick. Seriously....

So why the recent pondering?

Well, a .70 AR divided T4 housing fell into my lap. Perfect. I can now sell the HX40 since I was missing a turbine housing for it.

Oh, but wait.

There's a company out there selling a 67mm BILLET compressor wheel and matching housing for the HX40 capable of 900+hp!!!!

Now, why is this even being considered????

Well, from reading dozens of Supra dynos in the past, a .70 AR divided T4 housing (P trim turbine if you were wondering) is good to 700+ wheel hp and allowing rediculous, quick spool on a 3.0L engine.

Hmmmmmmm......

Best of BOTH worlds! Quick spool and big hp potential.....

Why am I on the fence with this? Its a no-brainer IMO for the Holset upgrade.

Seriously, why am i not jumping all over this? Well, it's really stupid, but the sound of the BW at boost sounds like a jet engine. The Holset, a beautiful turbo whistle. I don't want to lose the BW jet engine sound.

//Little devil on shoulder\\ ------ Come on man! It's a billet compressor wheel! Who wouldn't want that?!?!

Sigh.....

Thoughts?

[quattrorunner]

Well jeez, good problems to have eh? 1stworld issues to consider......
Hmmmmm. What do you like more?
What I want to know is what is the weight of each?

[Tippy]

Originally Posted by quattrorunner

Well jeez, good problems to have eh? 1stworld issues to consider......
Hmmmmm. What do you like more?
What I want to know is what is the weight of each?

About a 15lb difference I think? Obviously, the BW being the porker.

BW is off a 10L John Deere, the Holset off a 8.3L Cummins BTW.

[quattrorunner]

I had the hx35 for a few minutes on my car. That turbo was seriously large. Heavy too. My Garrett was nearly half the weight and really small by comparison.
My needs are not the same as yours though.
And sound....I never hear the Garrett until the engine is off. Then it spins for over a minute after shut down.

[jsveb]

Tippy, great issues for discussion.
I don't have any insight to share since I don't have time or money to get my 930 MOT'ed. Until the car has been inspected, I can't do any mods.
However, as you might remember I have an hx-40 with a billet wheel sitting on the shelf. I have put on a smaller BEP housing. I also have an S362, which I rebuilt.
Along with a set of BandB headers I am looking fwd to be able to chime in on this.

Following with interest.

[Tippy]

Originally Posted by quattrorunner

I had the hx35 for a few minutes on my car. That turbo was seriously large. Heavy too. My Garrett was nearly half the weight and really small by comparison.
My needs are not the same as yours though.
And sound....I never hear the Garrett until the engine is off. Then it spins for over a minute after shut down.

Garrett's spool insanely quick with their large AR's (GT35R's run 1.06 AR's), thus exhibiting low back pressure ='ing higher hp, as you said, don't make any really cool whistling or jet engine sounds.

Bet you miss the Holset whistle, hunh?

[Tippy]

Originally Posted by jsveb

Tippy, great issues for discussion.
I don't have any insight to share since I don't have time or money to get my 930 MOT'ed. Until the car has been inspected, I can't do any mods.
However, as you might remember I have an hx-40 with a billet wheel sitting on the shelf. I have put on a smaller BEP housing. I also have an S362, which I rebuilt.
Along with a set of BandB headers I am looking fwd to be able to chime in on this.

Following with interest.

Do you have the billet 60mm, 6 or 7 blade I assume? Is it the Batmowheel?

That has the potential for over 600 possibly 700whp from what I remember? Great spool, big hp potential, and a nice whistle. What's not to like?!

[Tippy]

My big concern in reading the Supra dynos is the possibility these guys were running "clipped" turbine wheels.

This allows less back pressure for more power at the expense of slightly laggier response since the airfoils are shortened.

An old school big hp trick.

The Holset, in this case, has small wheel extensions giving them the characteristics of super quick spooling because there's more airfoil in the exhaust gas path.

This induces greater back pressure at higher RPM choking hp. How much? Dunno.

Hmmm......more decisions to be made......

[JakobM]

make the "6764" and you will see a different smile on your face

if using 3.0L supras for reference, I have configured and sold many turbos for race teams using this engine. Interesting in regards to smaller turbine size is 6 x supras I have setup for drifting application with a billet 6559 twin scroll T3, 14.7cm2, .70 A/R turbo making reliable between 500-600hp on dyno (which is enough needed for drifting) and still backpressure low enough for that power (that is only 59mm exducer on turbine wheel). I would never use that for 930 application though, but it shows that a much smaller wheel size can be configured for specific power range and completely change the "ball game"

For 700hp I tend to use 6564, for 800hp I use 6768, for 900hp I use 7668, for +1000hp i use 7677. All figures max crank hp related to pump gas and I would use same configurations for a 930. E85 is another story with more power per mm wheel. All billet 7 blade design, all true twin scroll header design. Others like bigger turbine configuration for broader usage, but also dont necessarely go that deep into detail of backpressure/header design.

a BW S366 is in comparison a 6673....meaning the 80/73 turbine Wheel (80mm inducer/73 exducer) is capable of a lot more than the compressor side (66 inducer / 91 exducer). Good for high power, but configured for power range outside the compressor and done so to ensure backpressure low enough in the worst scenarios IMO.

There is many HX40 configurations out there but as I recall most of them is a 6064 turbo meaning compr inducer 60mm (with 86mm exducer) and 64mm turbine exducer (with 76mm turbine inducer). So if you could get the 67mm billet Wheel for your hx40 with same 64mm exducer turbine Wheel then you have a 6764 turbo which IMO is a much better configuration. I have sold 6764 turbos in at least 4 applications and it works just fine, one of them being a 1.8L nissan 4 cylinder making between 500-700hp depending on boost/gas. It is a very aggresive setup. Keep turbine area >15cm2 for that power.

BTW, 900hp on a 67mm billet inducer compressor wheel is likely E85 only! normally about 750hp on normal gas. Same goes for the 830hp listed on the BW 66mm, just look at the compressor map

[jsveb]

Originally Posted by Tippy

Do you have the billet 60mm, 6 or 7 blade I assume? Is it the Batmowheel?

That has the potential for over 600 possibly 700whp from what I remember? Great spool, big hp potential, and a nice whistle. What's not to like?!

I don't think there is any Batmowheel to it, but it is a six blade billet wheel.

[Tippy]

Originally Posted by JakobM

make the "6764" and you will see a different smile on your face

if using 3.0L supras for reference, I have configured and sold many turbos for race teams using this engine. Interesting in regards to smaller turbine size is 6 x supras I have setup for drifting application with a billet 6559 twin scroll T3, 14.7cm2, .70 A/R turbo making reliable between 500-600hp on dyno (which is enough needed for drifting) and still backpressure low enough for that power (that is only 59mm exducer on turbine wheel). I would never use that for 930 application though, but it shows that a much smaller wheel size can be configured for specific power range and completely change the "ball game"

For 700hp I tend to use 6564, for 800hp I use 6768, for 900hp I use 7668, for +1000hp i use 7677. All figures max crank hp related to pump gas and I would use same configurations for a 930. E85 is another story with more power per mm wheel. All billet 7 blade design, all true twin scroll header design. Others like bigger turbine configuration for broader usage, but also dont necessarely go that deep into detail of backpressure/header design.

a BW S366 is in comparison a 6673....meaning the 80/73 turbine Wheel (80mm inducer/73 exducer) is capable of a lot more than the compressor side (66 inducer / 91 exducer). Good for high power, but configured for power range outside the compressor and done so to ensure backpressure low enough in the worst scenarios IMO.

There is many HX40 configurations out there but as I recall most of them is a 6064 turbo meaning compr inducer 60mm (with 86mm exducer) and 64mm turbine exducer (with 76mm turbine inducer). So if you could get the 67mm billet Wheel for your hx40 with same 64mm exducer turbine Wheel then you have a 6764 turbo which IMO is a much better configuration. I have sold 6764 turbos in at least 4 applications and it works just fine, one of them being a 1.8L nissan 4 cylinder making between 500-700hp depending on boost/gas. It is a very aggresive setup. Keep turbine area >15cm2 for that power.

BTW, 900hp on a 67mm billet inducer compressor wheel is likely E85 only! normally about 750hp on normal gas. Same goes for the 830hp listed on the BW 66mm, just look at the compressor map

Jakob, thank you for this most informative post! Awesome data points, and I think we have the same thinking on this.

Yes, I too disagree the 900hp potential as the HX40 compressor outlet is still the same ID, thus will not flow the CFM needed for 900. But, 750 is fine and probably my end goal.

So you really like the 6764. It's pulling at me...........a lot!

Just would hate to lose the goosebump inducing jet engine sound.

It's too bad I can't find a housing smaller for the S366. I can cut a S300 .83AR 68mm housing to my 73mm wheel, but that's only an 8/10's reduction in AR (.91 down to .83).

Not very promising for the money and work.

If there was a .7X AR housing I could cut for the Borg, I'd be all over it, and I wouldn't even be thinking about going back to the Holset.

But, the Holset in 6764 configuration is a guaranteed combo that gives all the best worlds.

I think I'm slowly convincing myself......

Thanks again on your informative post and comparisons! Mucho appreciated!

[Tippy]

Originally Posted by jsveb

I don't think there is any Batmowheel to it, but it is a six blade billet wheel.

Very nice!!! That'll be fun.

[smurfbus]

Mine is 60/86mm, 65/76mm now with #16 housing.

Edit: I mixed you up with racerboy or similar, sorry. Was (Jacob. Do you have split headers available? Iirc you were located in the baltia?)

[Norm K]

Originally Posted by smurfbus

Mine is 60/86mm, 65/76mm now with #16 housing.

Jacob. Do you have split headers available? Iirc you were located in the baltia?

So it looks as though the BW S300SX3-60 (part no. 177272) is a 60/84, 68/76. I'm not certain how the .91 a/r of the BW compares to a 16mm housing but one site I looked at makes it appear they're pretty close. I'm hoping this combination is good for a 930 because I have one showing up next week.

[JakobM]

Originally Posted by Tippy

Jakob, thank you for this most informative post! Awesome data points, and I think we have the same thinking on this.

Yes, I too disagree the 900hp potential as the HX40 compressor outlet is still the same ID, thus will not flow the CFM needed for 900. But, 750 is fine and probably my end goal.

So you really like the 6764. It's pulling at me...........a lot!

Just would hate to lose the goosebump inducing jet engine sound.

It's too bad I can't find a housing smaller for the S366. I can cut a S300 .83AR 68mm housing to my 73mm wheel, but that's only an 8/10's reduction in AR (.91 down to .83).

Not very promising for the money and work.

If there was a .7X AR housing I could cut for the Borg, I'd be all over it, and I wouldn't even be thinking about going back to the Holset.

But, the Holset in 6764 configuration is a guaranteed combo that gives all the best worlds.

I think I'm slowly convincing myself......

Thanks again on your informative post and comparisons! Mucho appreciated!

Glad my input is appreciated. The turbine wheel is not that easily changed on the S366. The turbine wheel size is the issue IMO. Yes, not all work is that cost effective to perform rather than shifting turbo. 73mm exducer is huge, and dispite if housing is descreasein area/size, I am not sure it would make the difference you are after and really small turbine area makes a lot of backpressure too. There is much difference between 64mm and 73mm exducer. I normally aim for the smallest turbine wheel in a configuration and then size up the housing (area) i.e. 64mm with 16,3cm2, 1.0 A/R, T4 divided, rather than the other way around. That experience have given me good results in terms of backpressure and spool-up. For your end goal of 750 crank hp on pump gas a 6768 19cm2 T4 divided would be a good choise, you both get a larger compr wheel which lower the turbo-shaft speed (compare compressor map on the shaft speed lines) and at the same time go down from 73mm to 68mm on the turbine wheel. But, 6764 is good packaged setup for sure but more a max 700hp setup with the 64mm exducer (pump gas)

[Tippy]

Originally Posted by JakobM

Glad my input is appreciated. The turbine wheel is not that easily changed on the S366. The turbine wheel size is the issue IMO. Yes, not all work is that cost effective to perform rather than shifting turbo. 73mm exducer is huge, and dispite if housing is descreasein area/size, I am not sure it would make the difference you are after and really small turbine area makes a lot of backpressure too. There is much difference between 64mm and 73mm exducer. I normally aim for the smallest turbine wheel in a configuration and then size up the housing (area) i.e. 64mm with 16,3cm2, 1.0 A/R, T4 divided, rather than the other way around. That experience have given me good results in terms of backpressure and spool-up. For your end goal of 750 crank hp on pump gas a 6768 19cm2 T4 divided would be a good choise, you both get a larger compr wheel which lower the turbo-shaft speed (compare compressor map on the shaft speed lines) and at the same time go down from 73mm to 68mm on the turbine wheel. But, 6764 is good packaged setup for sure but more a max 700hp setup with the 64mm exducer (pump gas)

I meant machine the turbine housing, not change the turbine shaft/wheel.

You really think the 6764 is maxed at 700? Was hoping for 750 overall.

[JakobM]

Originally Posted by smurfbus

Mine is 60/86mm, 65/76mm now with #16 housing.

Edit: I mixed you up with racerboy or similar, sorry. Was (Jacob. Do you have split headers available? Iirc you were located in the baltia?)

None available. I only make custom race headers (321). Twin scroll only. Normally supplied as a "package" with turbo and sofar only racecars out site Porsche. Will design my own 930 header due to my new toy 77 930 racecar that I imported from US last year and now completely disassembled. Love this car, think I got bitten by the bug. I am located in Denmark

[JakobM]

Originally Posted by Tippy

I meant machine the turbine housing, not change the turbine shaft/wheel.

You really think the 6764 is maxed at 700? Was hoping for 750 overall.

a 7 blade billet 67mm compr. inducer wheel is "normaly" maxed out around 800hp, so 750 is fine as to the compr. The limitation lies within the turbine exducer of 64mm. If it was a target it self to max out a 64mm exducer, it would be possible to reach 750hp with 64mm turbine exducer, you would then need a twin scroll T4 housing with overall area >16cm2 area which normally equals around 1.0 A/R depending on how wide/low the housing is (A/R is only a calculation between area and height, thus area cm2 is the "ISO" figure across type and brands for housing selection). Personaly, I would not recommend to try and max out a turbo on an aircooled engine due to backpressure and heat. If the goal is to be around 750hp I would look for a 68mm exducer. And still this is huge difference compared to the 73mm. All hp figures related to pump gas.

[Tippy]

68mm is pretty odd size here. Forgot the trim they're called? S?

Anyways, ultimately, my recipe will be the following:

-52mm ITB's or 75mm TB on stock 3.2 intake (not installed yet)
-3" IC plumbing and I inlet/outlet (not installed yet)
-993SS cams (not installed yet)
-1 5/8" headers w/divided T4
-3.4L P&C'a (7.5:1CR) on 3.2 base engine
-Stock 3.2 heads

Was hoping this would achieve 750fwhp staying at ~1.4 bar of boost.