Rotrex Supercharger?

[turbotwig]

Pretty much. If you want to get it at a better spot on the map, you've got to either get the mass flow up or the PR down. Unfortunately you're right at the speed limit of the supercharger, so you don't have much you do to play around with that. VE% improvements can help, but only go so far. All and all your dyno graph looks very driveable, but could certainly be improved.

The big problem is that within the Rotrex product line there isn't a great match for your current setup and power goals. The reason I mentioned porting is that the big chunk taken out of the surge side of the map can be somewhat alleviated by compressor shroud porting. I'd have to do a layout to tell you where to put it and dimensioning and all that. Unfortunately, that's basically impossible without a bunch of drawings (or unless someone does a complete inspection/measurement on the parts), so that's why I only mentioned it in passing.

-Kirk

 

[KazeSupra]

Get a second one...lol

 

[Lextreme II]

70mm (2,76inch)Rotrex pulley
120mm (4,72inch) crankshaft pulley

So with the 2.75" pulley u are maxing out already?

 

[turbotwig]

My mistake. The actual recommended maximum impeller speed is 90,000rpm, not 100,000rpm, for the C38-61. That means the unit is at the maximum recommended speed at 7000 engine RPM with your 120mm/70mm pulley ratio. If you want to slow it down, you need to go with a larger supercharger pulley or smaller crank pulley. The 70mm supercharger pulley is the smallest pulley that Rotrex offers for that unit, so you have plenty of wiggle room if you want to change your setup.

-Kirk

 

[Tradewind]

What sort of pressures are we talking here, boost pressures??

 

[turbotwig]

He's running somewhere right around 22psi.

-Kirk

 

[Lextreme II]

I think ismo is running 9.5 psi with above pulley sizes.

 

[Tradewind]

9.5 sounds realistic

 

[ismo67]

Yep 0.65bar =>9.45pSI

 

[Lextreme II]

Ismo,

Why dont you get a bigger crank pulley. Looks like it was custom made. If you increase the size to 7.5" then u have plenty of room for future boost increase.

 

[turbotwig]

Something is not lining up with your numbers, the dyno chart, and the rotrex map, but I can't figure out what, yet.

The 274.5kW is at the rear wheel, correct? You're using the stock automatic, right?

-Kirk

 

[ismo67]

Here is some corrections I got from tuner.
Sorry, there was some mistakes.

The max pressure was at 7042rpm 12.24PSI = 0.844bar
And that horse power is not from rear wheel.
And using stock automatic yes then.
But now it is controlled by PCS.
Not dynoed after PCS and total exhaust change from original.
Please check also the engine tuner's comment (SporttiJanne) here:
http://lextreme.com/forums/showthread.php?t=3801

What do you think does somebody have experienses..
Does this motor rev safely 7500rpm?
Now I have limited rev speed to 7000.
It is very easy to change to 7500rpm.
Then we have some more boost also.

 

[Lextreme II]

Nice pressure.. is that stock motor u have?

 

[turbotwig]

What's up with your air/fuel readings?! It looks like it's misfiring.

-Kirk

 

[MWP]

What's up with your air/fuel readings?! It looks like it's misfiring.

Looks like it was bouncing off the rev limiter?

 

[turbotwig]

That's what I figured if it weren't detonating... which makes me doubt the boost numbers because you're basically sitting there with "anti-lag" on the rev limiter.


The power, blower RPM, blower mass flow, boost, etc. don't line up, which is bugging me.

-Kirk

 

[ismo67]

Nice pressure.. is that stock motor u have?

Yep, still but how long it lasts??? I would like to try 7500rpm now...
shall we hear an explosion ?..
I have multilawyer gasket & ARP's bolts bought from you David.
But nothing internal has been changed or modified.
And those parts are in my garage - not installed :redface:

 

[ismo67]

What's up with your air/fuel readings?! It looks like it's misfiring.

-Kirk

Something to do with the Autronic SM2 because of the rev limiter?

 

[Lextreme II]

larger crank pulley will work great.... If you car is a stree driven, you dont have to go up to 7500 to get full power. Larger crank pulley will bring the rpm alot lower to get the same boost.

 

[ismo67]

larger crank pulley will work great.... If you car is a stree driven, you dont have to go up to 7500 to get full power. Larger crank pulley will bring the rpm alot lower to get the same boost.

But it is easy to try with 7500rpm... have anybody done that with stock engine?
Does it rev so high & valve springs can handle that etc ?
I mean 7000rpm runs rice, no problem.
When I drive my car at street it of course does not have the belt on :veryhappy
That is also the reason I did choose centrifugal system.
It is very easy to do NA from FI... few minutes and done.