Thread: SC confused !
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      11-05-2012, 06:59 PM   #291
Sal@Evolve
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Another test of the Rotrex C38-91 vs Vortech V3Si on the same car
Car - BMW E39 M5
Evolve 4-1 Tubular Headers
Evolve High Flow 200 CELL CAT's
Evolve X Pipe and rear exhaust



This is the closest test we could run. The next Rotrex pulley size takes boost to 8 PSi. Did not have Vortech pulley to hand to test so this is as close we could get it.

You can see again, it's very close. You can clearly see if it was possible to take the Rotrex up another 0.5 PSi with a custom pulley the power and boost are matched.

Both blowers are about the same percentage through their max rpm's.
Rotrex is at 81000 / 90000
Vortec is 46000 / 52000

This particular engine setup requires way more airflow to make decent boost. The headers are massive (double in volume of the Supersprint design) and drop the boost levels dramatically as the stock headers are highly restrictive.

Notes:
Vortech was tested with 4 degC ambient temps
Rotrex was tested with 14degC ambient temps
Similar free flowing intake design
Standard Plenum

That's two major platforms now with evidence. If anyone else has proper evidence like this on the same dyno under controlled conditions (we can show this) comparing Vortech vs Rotrex then please post it up rather than make an assumption.

All of this backs up the comparative compressor maps and shows their theory works quite well but can show a variance depending on the type of engine used.

Interesting point to note - boost curves are far more similar in shape on this engine than on S65. Discuss....

I will be able to show results of S54 on both too.

Maybe S85 if I can find the time.

Last edited by Sal@Evolve; 11-05-2012 at 07:05 PM.
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