supercharging a turbo?

[Esasky's85GN]

gents,

This may be a off the wall question, but has anyone put a supercharger on a GN and fed it right to the turbo? From what I hear, this drastically reduces turbo lag and greatly increases horsepower. Comments and /or information always welcome!

Spank

 

[BLACK6PACK]

Lag is an overused excuse not to use a turbo. If you have the proper turbo and converter for your combination there is no lag. If for some reason you are running a monster turbo and have a stock unopened longblock a little 50 shot of nitrous will spool the turbo up NOW, and is much cheaper than dealing with a supercharger.

 

[Esasky's85GN]

I know about the nitrous and the way it reacts with a turbo but how cool would it be to have a "super" turbo charged GN?

Spank

 

[ijames]

I know some diesel big rigs use both, but I think they use a turbo feeding an intercooler feeding a supercharger setup.

 

[bruce]

Compound Supercharging, was all the rage in WWII fighter aircraft. Googling NACA, etc, will generate a wealth of information, and it's turbo feeding supercharger to be most effective, at least based on the successful past designs.

I've thought of plumbing in a centrifical S/C and doing that, just not enough budget.

 

[turbo2nr]

If you want more boost, use a staged turbo setup. Like tractor pulling. Two smaller (or even stock) turbos, one feeding into the other, with intercoolers after each. The stock location intercooler for the first stage, then a front mount for the second stage. The book "Turbochargers" has a section on weird stuff like that. There was a drag car (rail type) with both a supercharger, and a turbo in it. The book is by HP publishing, author, Hugh MacInnes. Grey Hound busses have both! But we all know that turbos are more efficient than centrifugal, or roots superchargers. The king is the Lysholm, or twin screw style supercharger, with up to 90%efficiency. Ever heard of an axial style supercharger? How about a comprex style? Looks like a gerble wheel (squirrle cage). Mercedes cars now have these sweet blowers (Lysholm). IHI makes them in JAPAN. I think Kenne Bell also has one. i can think of at least five other types of blowers. Piston type, vane type, on, and on.

Scott H.

 

[bruce]

Originally posted by turbo2nr
If you want more boost, use a staged turbo setup. Like tractor pulling.

Very difficult to get really right.
The multistaged tractors are about in turbine area technology. ie using the turbines to run the ICE.

BTW, some of the serious tractor multistagers are running upwards of 300 PSI.. Yes, Three Hundred PSI of boost.

I got to examine one multistager, that spit it's cylinder head off, and about 20 yards down track. It was a IH 466, I forget the displacement, but it sheared all of them, 1/2 bolts and 6 per chamber.

 

[turbo2nr]

I've read all about it, but am no expert by any means. I was not suggesting 300psi. But rather two small turbos to run in the neighborhood of 35-40psi, without the lag of one BIG turbo. Matching staged turbos is hard from what I've read. But it is not that hard. There are plenty of formulas avaliable. I'm sure two stock GN turbos would work fine. ATR has headers, but I've only seen parallel set-ups, not in series (staged). What do you think would be the benefits/drawbacks from such a setup?

Good discussion...i like you Bruce...sorry i jumped on you a while back!

Scott

 

[bruce]

Originally posted by turbo2nr
I've read all about it, but am no expert by any means. I was not suggesting 300psi. But rather two small turbos to run in the neighborhood of 35-40psi, without the lag of one BIG turbo. Matching staged turbos is hard from what I've read. But it is not that hard. There are plenty of formulas avaliable. I'm sure two stock GN turbos would work fine. ATR has headers, but I've only seen parallel set-ups, not in series (staged). What do you think would be the benefits/drawbacks from such a setup?

Good discussion...i like you Bruce...sorry i jumped on you a while back!

Scott

Tuned properly, and with the right converter, lag is a none issue, IMO. Most any car that's fast enough to run some really big numbers takes finese. Other then a 600 CID nitrous motor with alot of clever staging, any engine has to get into it's sweet spot to get going.

There are designs that are best used on specific applications, is what I was trying to say. There have been several road cars with series turbo, and IMO, I've not been impressed with them.

You did?.
It's the net, I don't take things personal.

 

[turbo2nr]

Don't you think two staged turbos would have a larger "sweet spot" than one larger one? Less converter needed, better drivetrain efficiency overall? Sure a big turbo can work great with a high stall, but that hurts the efficiency on the top end, unless you lock the converter, but I no longer like to abuse my tranny/converter like that. I like the non-lockups for big power.

I would also add a connector pipe from each banks exaust to keep the exaust pressure even to each turbo, so both sides have a better chance of equal flow. i may try this set-up if I ever win the lottery.

 

[BLACK6PACK]

If you're going to run one turbo into another one has to be small like the stock gn and the other would have to be a big turbo like a t70+. Again there is no reason to do this. There are people on this board running 70s on stock motors. All you need is the right converter. Also there is no reason to run 40 psi of boost, cus the 109 block isn't going to handle it for very long.

 

[XLR8]

Don't the fast ( or at least high horsepower dyno-queen ) Supras usually replace the twins with one big turbo?

 

[BLACK6PACK]

Yep, the supras take off their staged turbo's and put 1 big hairdrier on there.

 

[turbo2nr]

No, they have sequential, parallel turbos, not one feeding into the other. Totally different concept.

 

[bruce]

Originally posted by turbo2nr
Don't you think two staged turbos would have a larger "sweet spot" than one larger one? Less converter needed, better drivetrain efficiency overall? Sure a big turbo can work great with a high stall, but that hurts the efficiency on the top end, unless you lock the converter, but I no longer like to abuse my tranny/converter like that. I like the non-lockups for big power.

In theory, yes.
On a pulling tractor, sure, they can use them.

The efficiency is from having two turbines to pull energy out of the exhaust. There is only so much energy a *small* engine will have in it's exhaust. While great for a 600 CID pulling tractor, or 1,300 CID aircraft engines are very different applications then a Buick.

But, the compound setup (T/C and S/C) still, IMO, sounds like something too neat. Maybe as a test mule get a late 3800 S/C, and add a turbo to that.

 

[nocutt]

Enjoy:

http://www.fiero.nl/forum/Forum1/HTML/044129.html

 

[Drac0nic]

Originally posted by turbo2nr
I've read all about it, but am no expert by any means. I was not suggesting 300psi. But rather two small turbos to run in the neighborhood of 35-40psi, without the lag of one BIG turbo. Matching staged turbos is hard from what I've read. But it is not that hard. There are plenty of formulas avaliable. I'm sure two stock GN turbos would work fine. ATR has headers, but I've only seen parallel set-ups, not in series (staged). What do you think would be the benefits/drawbacks from such a setup?

Good discussion...i like you Bruce...sorry i jumped on you a while back!

Scott

I'm thinking heavily on sequentials for my project, but I've also got space to play with. I'm thinking about a pair of stock turbos for my setup. Since I'm doing electrical engineering stuff in school, I'm planning on building a digital controller with a pair of MAP sensors (one for each stage) that will allow me to control the wastegates for both turbos, thereby (hopefully) keeping em in their sweet spot. What I'm afraid of right now is the wastegate on the second turbo being big enough, the exhaust volume may not be high enough to prevent overboosting and spiking. The other thing I'm afraid of is how much effect modulation of the second wastegate will have on the first one. Indeed most people ditch the twins on Supras, but the question is how much of that's just "slap a bigger turbo on it" attitude versus it being actually better for performance.

 

[Lunkan]

Sorry, this is not a Buick, but I just wanted to share a webpage with You guys. This is a -71 Opel Manta with a super- and turbo- charged 2.5L Volvo B230 engine (4 cylinder).

The person who owns it has manufactured EVERYTHING by himself. You can find some videos on the page too, here´s a link to his 10.63 @ 135.6 run. Just listen to that sweet sound. And don´t forget to check his pictures, they talk for themselves.

 

[Tony87gn]

Heh that one guy at the end went 11.72 at 192 MPH pretty impressive MPH i would say

 

[turbo2nr]

That video is funny! The audience is clapping like at a tennis match, or after a golf putt. The car sounds wicked! Like a Ford Lightning and a turbo Honda put together.

You will never see anybody clapping at a drag strip in USA.