Turbo help needed

[Turbo_Crazy]

So a friend was asking me what the difference between a single and a twin scroll turbo was.
I dont know so I figure I would bring it up here and get other peoples pros and cons on this topic
he has an rb25 and wants to make 5-600 hp but wants as little lag as possible

let me know so I can let him know what the difference and maybe what you suggest for turbo

Thanx, Brad

[Bruizer]

Have you tried google..... lol it was never a factory option on nissans but was popular on the spec C sti if I recall. It's pretty cool.

You want 600hp with no lag get a v8 or push some samller twins real hard.

[r33_gtst]

twin scroll manifold= A divided manifold which helps with spool and response
On a 6cyl manifold like ours.......3 cylinders merge together on one side, the other 3 cylinders merge on the otherside.
The flange is divided so the air running into the turbo is more efficient than all coming together in a large open housing

[Skym]

Compound charging. Small supercharger / big turbocharger or small turbocharger / big turbocharger. Look at the old Group-B rally cars in Europe, as compound charging was used on them to make hp with little lag.

http://www.youtube.com/watch?v=y-Me6yWApzY

[r33_gtst]

WOW
thats pretty bad ass
who's gonna be the first to do it on a skyline?
i assume its probably been done but havent seen it

to play fantasy for a second..... what two turbo's would you use for an RB set up?
my mind is racing and i have the tuner/fabricator for such a project

[Skym]

Compound charging is commonly done in US on diesel engines, Lotus (Honda??) engines, etc and in Europe on Group-B rally cars, etc.

Also done on SR20DET in a few countries, including Japan, NZ, etc.

BEE-R made a compound setup for SR20DET in Japan -

https://www.youtube.com/watch?v=4SjNgVH_HN0

I have heard of compound turbo setups for Skylines, but never saw the final result. The owners probably didn't show the final piece or never finished the project.

There was a big hp red R34 RB26 in Japan with supercharger / 2x big turbocharger compound type of setup for display purposes -



Compound setup (small turbo / big turbo) is fun to drive (mentions turbo's they used at the start) -

http://www.youtube.com/watch?v=42Xa1HO1IwI#t=161

A set of Precision turbo's (good spool) would work.

Group-B rally cars were powerful, dangerous, hence they were banned -

http://www.youtube.com/watch?v=YGA0MSYaNHY

Audi Quattro (compound setup) = 3.1sec to 100km/h. I think that's off road and didn't have a sequential gearbox.

Look at 2:00+ to see incar footage and can tell it doesn't have a sequential gearbox -

http://www.youtube.com/watch?v=1x3ytEoNqRc

[Dragon Humper]

5-600hp without too much lag is not going to happen. You are going to be spooling at 4000rpm no matter what you do....unless you go twin charged like the BeeR car.

The simplicity of the BeeR Silvia is awesome, all they did was attach the supercharger to the intake side of the motor and blow a bigger than optimum turbo into it. Makes 500hp and instant torque at any RPM....like a 6L V8 would.



Jon.

[r33_gtst]

for a 00-600 whp skyline, what two turbos would be ideal for a twin charge set up?
i can see a precision 6266 as the bigger turbo but how small would the small turbo be? a little td03?

[Skym]

You need to do the calculations (maths). Turbo's are matched to engine capacity, hp you want and if they keep within the compressor map limit's (don't hit the surge line causing the flutter sound) or run out of puff at higher boost levels (run off the compressor map), thus making the boost plot drop off at higher rpm (changes when using E85 that some big hp compound turbo setups need, as turbo's are hp rated using pump gas). Once the calculations are done, can plot it on the turbo's compressor map.

What I mean it's different with E85, is could get another +50-100hp (depends on how much ignition timing you run) at same boost level while running on E85 gas vs running on pump gas. If turbo is rated to say 300hp, but can get 400hp out of it while running on E85 gas.

From what I understand, compound turbocharging is different, as the smaller turbo would have to spin to higher boost levels (say 2.3bar x 14.5psi = 33.35psi), but not go outside the compressor map limit's, bigger turbo would be at a lower boost level, but be within the compressor map limit's. Basically look at the hp level you are aiming for and match turbo's to it using calculations, compressor maps.

I gather this is why superchargers are a option, as they output more air at lower boost levels than a smaller turbocharger, but they drag on the engine and have next to no? lag.

It's scary to drive when you put it into a little Corolla?? (Finland??) -

http://www.youtube.com/watch?v=FG0uxjtg6yQ

Dyno -

http://www.youtube.com/watch?v=IWGuhkSRTvo

Look at the dyno graph, near perfect powerband (like you would see with a dyno graph for a stock engine) with 520hp at rear wheels.

http://www.youtube.com/watch?v=3WLj-gv5sUY