KA-RT or RB-RT why not?

[lewbaseball07]

After being asked stupid questions about turbos and superchargers the "why not supercharge and turbocharge a motor" question is always the best. I never know how to respond other than "Yeah, you just don't do that".

Well why not? The fastest rally car of all time(lancia delta s4) was supercharged and turbocharged. The whole point of it would be to use a HUGE turbo and have the supercharger spool that up sequentially. Would it really be that hard to put a clutch on the supercharger so that it would disengage when the turbo reached boost WITHOUT the help of the supercharger anymore? Better yet why not twin turbo supercharged? Have the supercharger spool up two huge turbos. It would give you a heck of a lot less of lag. So why not?

[allenms240]

moneyssss
You try doing that. lol.

[breadbox]

search for the true pig build there is a guy doing it right now. Not quite rallye set up yet but he's definitely doing it up. its probably on the first two pages in both ka fourm and the 240sx gen.

[costa_rican13]

moneyssss
You try doing that. lol.

monies indeed. goodluck with that and the amazing tuning your gona need! not mention the 1500cc injectors your gona have to give both you legs for.

[simmode1]

The RB26 already has ITB's. Why would you would to run a supercharger too?

[seang]

The setup would be complex, like the engine controls for a Honda CX500 turbo motorcycle.

[lewbaseball07]

So the answer is, it is too complex, too expensive, and to begin with it's kind of taboo to even think about supercharging and turbocharging something. Am i right?

[Genpac]

Volkswagen has a production twincharged 1.4l motor. I'm sure they have several million invested in the technology.

[krash]

[youtube]http://www.youtube.com/watch?v=4SjNgVH_HN0[/youtube]

[costa_rican13]

[youtube]http://www.youtube.com/watch?v=4SjNgVH_HN0[/youtube]

sweeet.....

[simmode1]

So the answer is, it is too complex, too expensive, and to begin with it's kind of taboo to even think about supercharging and turbocharging something. Am i right?

No. The answer is: if you've got the resources and knowledge to do it, go for it. If not, don't waste time speculating about stuff you're never gonna do. If you wanna learn about it, the info is out there. Just search for it.

[PantherRacer]

1989 Nissan March Superturbo. Just so you know, nissan said it's possible

[PapaSmurf2k3]

Volkswagen has a production twincharged 1.4l motor. I'm sure they have several million invested in the technology.

This man speaks the truth. I think its also direct injection if I'm not mistaken, which they have sort of optimized under "stratified" injection (again, if I'm not mistaken)... which kind of incorporates injector timing into the tuning aspect of things.

FOUND IT:
http://www.youtube.com/watch?v=20qqavckWdw

Those crafty 'krauts! I bet that water pump assembly is expensive as hell.
You know, I give VW a lot of s***, but they really do have a lot of really good ideas... and actually have the balls to implement them. Seems like they just choose crappy suppliers or something in this country.

[martins_240sx]

Expensive...no sc cost me iirc $275. I rebuilt it for $48. aluminum cost about 190 with the water jetting
complex....depends. im going in series, mercedes has a clutch that shuts off and re routes boost.
why not....bandwagon?, tunnel vision, could be he said this and that.

It is simple. to me. I asked many questions and did many pages of math just for it to be thrown out the window with simple climate or elevation changes.. It gets complex when you factor in boost multiplication..meaning 8 psi sc plus 8 psi turbo added to each vein of sc at given??? rpm could cause much higher than the assumed 8+8=16...could be excess of 20-25-30psi. since each revlolution is adding the 8psi pre compressed into each vein of sc then spun into the cumbustion chamber at an even faster rate than just the turbo could do...but with the complexity of that it is simple to adjust by simply putting your wastegate line in the actual manifold pressure trac. where the sc is your constant and the turbo is your variable for the given boost you are aiming for....and for the record one of the most widely used engines in the world "Detroit desiels 8v92 and other series come to the table twincharged and have been doin so since many of your grandparents were kids

I will be selling these kits to sc single cams and possibly duals

[simmode1]

I will be raking in lots o' dough

Correction.

Like I said, OP: If you got the resources and know how... go for it. I think the KA is a fine candidate for this. RB? Not so sure there. I've seen ppl swapping the RB26 ITB's onto their RB25's for increases in output and responsiveness. Seems like that would be easier for similar gains. But I'm not sure about the RB20. That might be a decent candidate. Go look into it.

[martins_240sx]

hahahahahaha thanks man

[seang]

A Detroit Diesel x71 engine is also a two-stroke (4 exhaust valves per cylinder iirc) that could not scavenge the crankcase without at least supercharging. It's beside the point, but notable.

[martins_240sx]

yes it is 4 exhaust and no intake valves. And it can scavenge the crankcase, just not efficiently enough to rely on it to power heavy vehicles...it would have horrible lag...hence the supercharger. It is also not controlled by any type of boost regulation. ''wastegate" but another thing is the supercharger on those engines typically rotate the sc 7 to 1 on the crank case as apposed to the more desireable 12-14 to 1

[PantherRacer]

http://www.youtube.com/watch?v=ThOMuTf6 ... re=related
http://www.youtube.com/watch?v=1F43fNZUVB8
Superturbo Powaaaaaaaa

Homologation special, so it was limited run. Who knows, if Nissan had kept it up maybe we would've seen another light Superturbo in the lineup?
GA16DERT? CA18DERT? SR20DERT?

I want soem DERT! So I can be ridin DERTY!

[breadbox]

^^Ha. ^^

[costa_rican13]

I want soem DERT! So I can be ridin DERTY!

[PantherRacer]

http://www.youtube.com/watch?v=yzRpz9c-t_o&list=QL This RB30 will scare small children. But it sounds godly.

[simmode1]

^^^Wait... sooo, instead of putting an RB26 head and manifolds on an RB30 block, that guy just built a turbo kit for it and installed a blower on the intake side?

Wow. 300whp might seemed low or moderate, but I'm scared of the torque I think that thing is making.

[PantherRacer]

Looks to be that he's got a 25head on the block, it is DOHC. so RB30DETR (DERT) check the link on his vid, seems he was going for 450 on stock cams next.

[alms24sebring]

http://www.youtube.com/watch?v=wLB2P1zi ... re=related
Dude this is the freakin sweetest, truest sleeper evar! DO WANT!!

Its probly better suited for low boost applications. High boost apps although would be high hp and monsterous torque (thinking 1500+ hp/tq), I think it would be too hot; too heavy, everything would be oversized; and too expensive to even maintain as a regular racer. It would be very complex with fuel and compression ratios too, so that means lots of electronics with complicated tuning and specs. Although Im sure there will be a super sick one built one day.. just wait

[PantherRacer]

Only thing I wonder is what is better....super-turbo or compound turbo...Maybe someone should REALLY do something different and have a super compound turbo setup. :|

[alms24sebring]

Lol. It would probly be way too inefficiant with air going every which direction and disgusting heat. That would also be a huge setup to fit under a hodd. What would you use an old 90's Lincoln or Cadi tank... wait... hmmm. I like it tho, your thinking haha.

TT > RT

[martins_240sx]

one thing about the tt is still the "lag" and you will also have to worry about surge of either turbos. not saying it wouldnt work but the fact that the sc starts nearly instantly, especially in mid rpm reinstatement. the turbo would still have to respool. just my speculation..tt<rt

[PantherRacer]

But in compound turbocharging, the smaller turbo is sized so there is less spool time and you can have pretty good response, and similar results with sequential. Full twins I think would be less efficient than an RT. About the surge,that's what bov's and wastegates are for anyways. and you can get turbos with anti-surge housings if you do start surging to help with the problem. This does only really help if you have all your turbo math right from the beginning, if not, you're bound to deal with some difficulties.

Now with RT I think you would have that torque and boost on that engine sooner, say if you just wanted to mash it from the middle of a slow cruise in a gear a bit too high. Also all of the exhaust is going straight to the turbo, and if you have twin-scroll you can utilize those exhaust pulses right instead of through the exhaust housing and wastegate of a smaller charger. There's less exhaust piping and weight, and with a roots style blower there's less intake piping also.

the diplomatic way to say it is it's down to what you're doing with the car and how you want to drive it. But personally I think I'd take RT, two different types of chargers each strong where the other is weak? Besides, you can set it up so you can turn off the supercharger with a switch. That'd really give your car that "super action movie extreme machine" feel to passengers once you show them what it's really made of lol.

[martins_240sx]

surge- a compressor characteristic that happens when a compressor is asked to operate at a pressure level higher and mass flow lower than it can suppy. the compressor wheel instantaneously stops and restarts and a loud chirp or bark is heard....text book definition
it can be caused by using no bov. or when functioning outside of the turbo's range of operation