Staged Turbocharging

[RS/377]

Just out of curiosity, are there any NHRA rules banning the use of staged turbocharging systems?

I've looked into the NHRA rules and didn't see anything about it, and I'm just curious to why people don't do this.

 

[GalantVR41062]

staged as in the out let of one turbo feeds into the inlet of the next turbo? as in diesle truck pulling running 3 stage turbos(2into 1 then into another one) at 256psi manifold pressure(direct bore injection almost no worrys of detonation) . but you would need water injection to cool the air from one turbo to the next unless you plan on running twin FMIC and try to run piping for that. Or do you mean sequential like the RX-7 and the supra,Ferrari F-40? where you have two turbos one smaller then the other, have the small one spool first and then have the big one spool second, now this is ok if you dont plan on over running the small turbo. But unless you are running a bored out 2.4liter stroker 4G64 there is no point to having two turbos at all. if you want spool up and power go to AGP turbos, or go full Garrett GT turbo for that matter. hope this helps.

 

[RS/377]

Actually, I was just wondering about the rules.

Right now there are a couple of 4x4 diesel trucks running two stage systems that are almost in the nines, just wondering why you see it in one form of motorsports, and not the others.

 

[Enigma_Man]

Yeah, I think the main reason why the big rigs would have setups like that is just because they're quite different from our cars, or any other sportscar for that matter.

It just isn't practical to try and wedge two (or more) turbos into the already cramped engine bay. There's ball-bearing turbos out now that spool like mad, and can make 600+ horsepower on our cars as it is. Basically, it's a ton of work for no gain.

As far as the rules go, I don't see why there would be any particular rules for number of turbochargers used on the car. If any rules do apply specifically to a "turbo" car, I'm sure that incldes all of the bi-turbo, sequential, and whatever other convaluted setups people have.

-Jesse

 

[RS/377]

There's ball-bearing turbos out now that spool like mad, and can make 600+ horsepower on our cars as it is. Basically, it's a ton of work for no gain.

Now, assuming that the drivetrain would hold, you are saying there would be no advantage to being able to run 200 pounds of boost?

Again, I was just wondering if there were any rules against it, which would explain why people who run tube frame cars in the six second range, and plenty of engine room, aren't doing this.

 

[pneumo]

I don't think it's a NHRA rule. I think it's just not possible to run that much boost in our engines without some major redesigning first. There is no part of our engine designed for 200 or even 100 psi, although I'd like to think some are trying.

 

[GalantVR41062]

diesel fuel is why they can run 250+psi manifold pressure it buns different then gasoiline. But there should be no rules on what you do with turbos, just that you have power adders, ie boost(turbo/supercharger) N20, NA. then drivetrain etc then divided into classes, but you get the idea.

 

[RS/377]

I see, so its the fuel limiting this technology, not rules.

Thank You

 

[2-0turbo]

Yes, it is the fuel. Diesels are compression ignition engines--they don't have a spark. When the fuel enters, it lights off. Only way you could accomplish that on a gas motor is if direct-injection was a reality.

I have always wondered: how to those diesel motors keep the heads on running 250 PSI boost when we blow headgaskets at 30?

 

[RS/377]

Only way you could accomplish that on a gas motor is if direct-injection was a reality.

Mitsubishi 4g93, 1998 and later, JDM version.

However, I completley understand that is neither here nor there....

 

[2-0turbo]

Originally posted by RS/377

Mitsubishi 4g93, 1998 and later, JDM version.

I was getting ready to say you were full of it, then started looking on the web and found the very engine you describe. This will be the next major stepping stone for the IC engine. That an infinitely variable valve control will produce some wild engines!

I was unaware that there were production auto gas engines utilizing GDI. Outboard boat motors have started using it a couple of years ago.

 

[mrmadmax]

Originally posted by 2-0turbo


I was getting ready to say you were full of it, then started looking on the web and found the very engine you describe. This will be the next major stepping stone for the IC engine. That an infinitely variable valve control will produce some wild engines!

I was unaware that there were production auto gas engines utilizing GDI. Outboard boat motors have started using it a couple of years ago.

Haha, keep surfing, BMW's way ahead of you. Variable Valve timing, variable lift (eliminates throttle body all together), Direct Injection, etc.

"Let's take a look now at the most significant new technology in this new engine: direct fuel injection. Indeed, this is the first direct-injected gasoline V-12 engine ever offered in a production automobile, and the first direct-injected gasoline engine to meet contemporary expectations regarding emission control.

Direct fuel injection means injection of the fuel directly into the combustion chamber, rather into the intake port as is the norm; it has been chosen and developed by BMW's power train engineers to boost power output and fuel efficiency ... yada yada yada

Product highlights

.... yada...

Performance & efficiency
• DOHC (4-cam) 48-valve V-12 engine: 6.0 liters, 438 hp, 444 lb-ft. torque. Engineering features include –
• Direct fuel injection (first direct-injected gasoline V-12 ever offered)
• Valvetronic system of variable valve lift
• Double VANOS variable valve timing
• 0-60 mph in 5.4 sec.
• New STEPTRONIC version of 7 Series’ 6-speed automatic transmission"

The above taken from Here

Also saw a write up in Race Car Engineering Magazine...

 

[T6Rocket]

FYI, on a twin turbo car, they are exactly that - twin turbos! One is not larger than the other one! IF it was, the smaller one would restrict the output of the larger one, making it perform the same as the smaller one.

It doesnt help that we have major publications like Car & Driver & Turbo saying things like "the first turbo comes in around 2500, and big brother crashes the party around 4000"!

Al

 

[GalantVR41062]

sequential is different then staged turbos... as stated above(post#2).
and some cars run one small and one large turbo(F-40, RX7) but it could also be how the waist gates are set up and what boost each turbo runs, dont the supras burn one of the turbos unless you re-rout the vac lines to the waistgates, so they come on the same time etc?