One Turbo, One Supercharger, One 6.2L Engine.. Possible?

[john8662]

Thanks for reading...

Ok, here is the situation, I want to use ONE turbocharger (banks, or Factory 6.5TD setup), AND ONE supercharger (paxton, vortech, powerdyne) on the same 6.2L engine.

Here is the logic (yeah its fuzzy logic)

I want an engine that can generate good boost and be good off the line. The problem with most turbo's that I have had experience with, especially the 6.5 is that they have NO off the line power. You hammer the go petal, and it just sits there and foggs mosquitos with a BIG BLACK CLOUD if you have the fuel turned up. What a waste of fuel, no power for the fuel injected. Until, the turbo spools up and you get the extra air you need to burn the fuel. But once going and with increased engine RPM you have the boost you need to keep going. So I got to thinking...

What about a supercharger (engine driven turbo basically), say one from a car kit (camaro, mustang etc.) like a Paxton or a Vortech super, not blower. Why a supercharger? well faster boost responce, its engine driven (yeah, yeah, you lose power to make power).

So, here is the REAL question, could you have the best of both worlds? A supercharger set with say a 6psi pully to get you some take off boost and a turbo to take you from 6psi to 15+ once you get rolling and have the RPM's up?

I figure this would be a question for those that have made the twin turbo diesel setup's (like Peter's TTD CUCV Blazer).

Any problems with this idea (like turbo being spun backwards by the pressure of the super before the turbo can be spooled)? I don't know, I just thought that this would be neat if possible. Thanks for the read, and I appreciate your comments.

This is going on an 82 3/4 ton 6.2L truck (plain jane truck), Its got a 700R4 (yeah real POS there) but its got a 14bolt Full Floater in the back geared 4.10, A/C will be pulled out completly for turbo stuff. I have a factory 6.5TD setup in hand and am looking for a supercharger that might fit my need. Truck is in pieces right now, the engine is not in the truck.

[grape]

properly sized turbo's make boost quicker than a centrifigul super charger. A supercharger sets max boost based on max rpm of the compressor, or the engine. So you get max boost at max rpm, everywhere else suffers. My turbo'd mustang was at full boost, whatever I wanted by controlling the wastegate by 2800 rpm, usually 11-12 pounds. This carried all the way to the rev limiter at 6K rpm. I have lots of friends with vortech cars, and unless you are all over them keeping them in the desired rev range, boost isn't there. One car in particular has an older S-trim that isn't making a noticable amount of boost on his mustang till over 3500 rpm.....with a max of 9 pounds at 6000.

[jbell]

A centrifugal supercharger is not linear vs. engine rpm -- a roots or screw type supercharger (positive displacement) is.

[gmctd]

I agree with grape - out-boosting a turbocharger is practically impossible, given the 6.2\6.5 load range, where power is needed at low rpm, off-idle, and such.

Also, the cast-iron cranks have a rep of breaking at the #2 main journal, even with the mildly loaded accessory-drive system.

What would happen with the added 35-40hp load and heavy drive-belt whipping of a mechanically driven supercharger?

Yeah, I know - Hummers get Whipples, but not with the millions of miles success the factory GM turbodiesels have logged.

My factory-chipped TD makes 7psi Boost under load, off-idle, even on a bad day.
And could be adjusted up to 15psi (practical limit, not max limit), off-idle, if the charge-air cooler was finished and installed.

Are you saying you're having some problems with yours?

[Craig M]

The Detroit diesels of the 70's had the combination of supercharger and turbocharger that you are discussing. They were a two stroke engine. The turbo supplied boosted air to the supercharger on this set up. If I recall a 318 horsepower engine became a 350 horsepower engine when the turbo was added (on an 8V71).

[john8662]

gmctd and others,

I don't have a problem with my 6.5 for making boost, it just SUCKS off the line, Kinda smoky (stock chip), especially on a warm day. I will be adding intercoolers to the 82 truck as I have room for them. The 6.5 doesn't have the room. I make good boost, 9-10psi on the guage with my foot in it at times, it will spike to 12 before the wastegate is opened. I just observed the turbo situation on the 6.5 and have had the same conderns with a turbo 6.2 when I build it. I just want something to smoke them dern 350 whoretech engines in trucks, not fog them in smoke (except off burning tires). I was just curious if it would work or not. I am not interested in getting 200k miles on this engine either, so the load of the crank is not a big concern, especially with the examples of the whipple chargers out there on 6.2/6.5 hummers.

I think there are several ways to route the boost pressures. I was planning on sending the boost from both to the intake. But putting them in series would also work. Thanks for the comments.

[dieselhumvee]

I think it is a great idea, a turbo and supercharger going together detriot diesel style, if for no other reason than the coolness factor!!!! GEP the company that now makes the 6.5 for the Hummer offers a screw type (whipple)supercharger, as does a company called marine diesel. If time and money permitted, I would definitely lower the compression as low as possible and add a suypercharger and turbo to my 6.2.

[jcomp]

You can powerbrake to build up boost before you launch. Might be easier than installing a lot of plumbing and hardware.

[Peter J. Bierman]

Working or not, it would make a very neat combination :D

Going with two smaller turbo's eliminate the turbo lag without taking any power and still give you full boost.

Peter

[wthif]

I get very little turbo lag with out a muffler just a down pipe. The biggest cloud of smoke I get is a faint brown thing that lets people know its a diesel. I also have to try hard to get that. My question would be what turbo do you think you are going to go with? That will probably be the biggest determining factor when it come to turbo lag and smoke. Also what else do you plan on using with the trubo, high pop injectors a 4199 pump. These will also determine smoke. The better the burn the less smoke.

Though I also like the idea of supercharger being force feed by a turbo. :rolleyes:

Have fun either way smile.gif

[rhill2901]

My '93 RX-7 utilizes sequential turbochargers, the first one is smaller, and spools up very quickly, and the 2nd is massive, for top end performance. I don't see why this wouldn't work for a diesel application also...

Richard

[Dieselboy]

Originally posted by rhill2901:
My '93 RX-7 utilizes sequential turbochargers, the first one is smaller, and spools up very quickly, and the 2nd is massive, for top end performance. I don't see why this wouldn't work for a diesel application also...It does! - http://www.piersdiesel.com/DodgeTwins.htm

[grape]

my new toy, several posts on down the page.....
web page (http://67-72chevytrucks.com/vboard/showthread.php3?t=106960&page=2)

[john8662]

An RX7 turbocharger? say, I never thought of that an I have family that has one of those cars. Its a 93 RX also. I'll have to pop the hood and take a look see at the turbocharger. I also need to sucker him into installing a boost guage in it so I can see how fast it makes its boost and how much boost it makes. thanks for the suggestion.

I think the main point about my supercharger idea was making instant boost, which in reality it won't. But it does make it easier for adding an additional compressor for boost. Besides adding a turbo and doing all the exhaust work. Thanks again for the suggestions!

[Colorado Kid]

NO2 is very effective for clearing exhaust smoke and creating tire smoke in Diesels. :cool: It'll also help you get that turbo spooled up.

[CleviteKid]

Make that N2O. NO2 would dissolve most of the components inside your engine, and kill anyone behind your truck.

Dr. Lee :cool:

[john8662]

OK, off topic here, so we have the suggestion of Nitros. What about just pure Oxygen? If I can clear up the smoke before the turbo spools that would help, thats all i am after. I don't want this truck to look like a freight train when I take off.

[Peter J. Bierman]

There was a time that my truck did not produce any smoke, neither from the exhaust nor from the tires.
I cost me a small fortune to get the engine smoking and are close to have the tires do the same.... :D

So, smoke is a good thing ;)

Peter