Compound turbocharging?

[slimtastic]

Compound Turbo Charging - Yellow Bullet Forums

this thrread had me reading for quite a while. has anybody in buick land ever done this style of turbocharging? i figure it would be more benifical for our cars as a buick is quite limited in rpm so the more effective powerband you can have "in boost" the better

having a stock turbo for the primary and a 72 gtq for the secondary would be quite a killer combo if done right.

thoughts?

 

[notacarlo]

Compound Turbo Charging - Yellow Bullet Forums

this thrread had me reading for quite a while. has anybody in buick land ever done this style of turbocharging? i figure it would be more benifical for our cars as a buick is quite limited in rpm so the more effective powerband you can have "in boost" the better

having a stock turbo for the primary and a 72 gtq for the secondary would be quite a killer combo if done right.

thoughts?

That would be going backwards. The Supra guys take off the secondary and go with a big primary to go fast.

A 72 and correct stall is all you need.

 

[slimtastic]

not all of the supra guys do that... and when i talk in "secondarys" im talking about the second turbo that will make boost. the smaller turbo would be the primary cause it kicks in way quicker than the secondary

Boost Logic SupraTT Compound Turbo Kit :: Turbo Kit :: 93-98 MKIV Supra TT :: Toyota :: Boost Logic

besides whats the stall required to spin up a 72 millimeter turbo on a 3.8? somthing near 4000 stall for a journal bearing?

even if you got the "best of the best" in terms of a newer technology stall that is 95% efficient on the top end, you still have a huge stall thats kind of a dog around town and kills any attempt of gas mileage.



novel idea if you read the whole thread

 

[GNVYUS 1]

As far as I know, I haven't seen it on a GN or Stage II etc engine. I can see some benefit to a Stage II or TA racing engine but it's still limited by total psi.

This wouldn't be as beneficial as you think for us, some things to keep in mind.

1) We generally don't have spooling issues for high 9 and slower vehicles
2) Our heads can't take advantage of the high psi compound turbocharging offers since they won't stay on at 40+psi
3) The cost vs performance on our platform doesn't make much sense vs Nitrous

Take a look at what vehicles use this and make tons of power, all of which can handle 40+psi without issue as long as the tune is there.

I don't see someone spending an extra $4k plus vs Nitrous in the 9 second and slower crowd here. Someone shooting for 6's, 7's and maybe low 8's, but I'd think there would've been a kit out there if it was practical by now.

 

[slimtastic]

I can see some benefit to a Stage II or TA racing engine but it's still limited by total psi.

This wouldn't be as beneficial as you think for us, some things to keep in mind.

1) We generally don't have spooling issues for high 9 and slower vehicles
2) Our heads can't take advantage of the high psi compound turbocharging offers since they won't stay on at 40+psi
3) The cost vs performance on our platform doesn't make much sense vs Nitrous

I don't see someone spending an extra $4k plus vs Nitrous in the 9 second and slower crowd here. Someone shooting for 6's, 7's and maybe low 8's, but I'd think there would've been a kit out there if it was practical by now.

good points you make, i was more or less gearing the idea and thoughts toward a potent 500+hp streetcar that would keep boost to a manageable 25-27 psi on alky. all the while having a super tight(damn near stock) stall with boost right out of the hole, and then some really good top end power as well..

by no means am i looking or suggesting 40+lbs of boost on a 109 block. im just brainstorming how to get 15 lbs at 2400 rpm (or less) while still having turbo efficiency up to redline


im thinking the primary (small turbo) could be wastegated to 12-15 lbs and have the secondary turbo (big turbo) wastgated to 5-7 lbs with a boost controller

 

[RatFink]

Didn't Bugatti use this approach several years ago? I think it had 4 turbos.
2 little ones, and 2 larger ones. Don't know, but interesting topic.

 

[christians87]

This method of turbocharging is very popular with the cummins diesel guys. Its not uncommon to see those engine sporting there stock turbo with a massive charger hanging right below. Of course these are diesels were talking about here which can safely handle much higher boost levels . Just saying, it is a proven method on the larger platforms...

 

[Alky V6]

As far as I know, I haven't seen it on a GN or Stage II etc engine. I can see some benefit to a Stage II or TA racing engine but it's still limited by total psi.

This wouldn't be as beneficial as you think for us, some things to keep in mind.

1) We generally don't have spooling issues for high 9 and slower vehicles
2) Our heads can't take advantage of the high psi compound turbocharging offers since they won't stay on at 40+psi
3) The cost vs performance on our platform doesn't make much sense vs Nitrous

Take a look at what vehicles use this and make tons of power, all of which can handle 40+psi without issue as long as the tune is there.

I don't see someone spending an extra $4k plus vs Nitrous in the 9 second and slower crowd here. Someone shooting for 6's, 7's and maybe low 8's, but I'd think there would've been a kit out there if it was practical by now.

x2.
A small shot of nitrous solves a lot of problems.

 

[GNVYUS 1]

Well if there's someone who would build a kit and make it happen it's the guy above, DonWG.

Maybe someone should tell him he can't do it and we can see one in existence in 2 months doing 7's with the Afterburner and Nitrous!!!!

 

[charlief1]

That would be going backwards. The Supra guys take off the secondary and go with a big primary to go fast.

A 72 and correct stall is all you need.

He does exist!:biggrin: Give me a call you bum, or at least email me on what's been going on.:smile:

Well if there's someone who would build a kit and make it happen it's the guy above, DonWG.

Maybe someone should tell him he can't do it and we can see one in existence in 2 months doing 7's with the Afterburner and Nitrous!!!!

Boy, aint that the truth.:biggrin: Come on Donnie, show them how it's done.:biggrin: