Jackson Racing Rotrex Supercharger System Info and Discussion

[wheelhaus]

Originally Posted by choi0706

does anyone have a boost graph with this kit?

Posted several pages back. Is this what you're looking for?
The boost rises linearly with RPM.

[Jackson Racing]

Originally Posted by raul

@CSG Mike @Jackson Racing

Or anyone for that matter. How much weight does the kit add to the car, roughly? Anyone taken the time to weigh it?

We haven't had the chance to weigh our FR-S yet, but I would guess the system installed adds +/- 30 lbs. I am guessing based on our other kits with similar components.

-Oscar Jr.

[enivid]

Getting close. Just waiting for the oil cooler to arrive and then will install the intercooler and wrap it up!

[Ocho Seis]

What intercooler did you go with ?

[enivid]

Originally Posted by Ocho Seis

What intercooler did you go with ?

The one that it comes with

Or if you meant oil cooler, I'm waiting on the JR oil cooler which I hope will arrive very soon.

[Ocho Seis]

my bad I ment oil cooler ...

[enivid]

Originally Posted by CSG Mike;

Just fine. The Rotrex is a proven supercharger, and is OEM on some exotic cars as David mentioned.

We've done our own testing with Rotrex superchargers (albeit on a different car) at 4000+ ft elevations, without issue. Datalogs show ambient getting as low as about 12.5 psi (vs 14.5 psi at sea level).

Do you have a guess on what the hp loss is at 4000+ ft elevations for this supercharger?

[CSG Mike]

Originally Posted by enivid

Do you have a guess on what the hp loss is at 4000+ ft elevations for this supercharger?

It's more or less a percentage... same applies for any FI setup.

[mit_peid]

Originally Posted by CSG Mike

It's more or less a percentage... same applies for any FI setup.

Do FI setups take a higher % drop compared to NA cars at elevation? Say a turbo car makes 300whp and a NA cars makes 200whp at sea level. Going up to 4000 ft, would the turbo and NA car both drop approximately x%?

[qtwre]

Originally Posted by CSG Mike

It's more or less a percentage... same applies for any FI setup.

Won't a turbo just spin faster to hit the same boost target, regardless of elevation? Oh, but then I guess intake temperatures would go up, losing power.

Touche.

[CSG Mike]

^ That.

One thing people don't realize, is that the turbo Bimmers and Mercedes cars gain a TON of power from reflashes, because they actually have the capability of making more than their rated horsepower from the factory. Why? Because the manufacturer wants the car to make that power in a variety of conditions, not just under ideal conditions.

For example, an older 300hp/300tq BMW 335 will make 300hp/300tq at sealevel, as well as at 4000 feet above sea level. How does it do it? By utilizing more of the overhead that is left as a margin for consistency in output. However, a reflashed 335 will not have that consistency. After a flash, the car may make 360hp/345tq at sea level, but only 320hp/320tq at 4000 feet above sea level.


I've never said this before, but this 0-125 video was shot at high elevation, above 4000 ft.

[ame="http://www.youtube.com/watch?v=KHZTjIKNpNU"]Jackson Racing Supercharged BRZ (FR-S) 0-127mph run - YouTube[/ame]

[jamesm]

if you lose power when you go up in elevation on a turbo system (i.e. the turbo can't keep up due to an inability to push the PR required to maintain target boost at that altitude), your turbo is way too small.

this isn't a realistic concern with any of the turbo kits available for this platform.

[tendogy]

Originally Posted by CSG Mike

I've never said this before, but this 0-125 video was shot at high elevation, above 4000 ft.

Whaaaaaaaaaaaaaaaaat?!?! You got so much crap for the lack of acceleration (relatively speaking) in that video and you didn't want to mention that it was at elevation? So you were only at ~22psi instead of ~24psi; that explains everything.

[CSG Mike]

Originally Posted by tendogy

Whaaaaaaaaaaaaaaaaat?!?! You got so much crap for the lack of acceleration (relatively speaking) in that video and you didn't want to mention that it was at elevation? So you were only at ~22psi instead of ~24psi; that explains everything.

:shrug:

the 0-60 is still faster than stock by a good margin, even with the granny shifting.

A supercharger's RPM doesn't change by elevation; a turbo can work harder to get to the desired boost (albeit, potentially also going out of the efficiency range). I'd say the absolute MAP was lower than 22 :p