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Dyno: APR Stage 2 Cali 91 octane

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SFvalleyGTi1

Go Kart Champion
Recently went APR Stage 2 with USP Catless downpipe. As I mentioned in my previous review, the TSI motor really stinks without cats. So I had my Bmw 335i cat welded onto the mid pipe... Got rid of the smell and some of growl.

I got the car on the dyno today to see if putting that Bmw cat hurt my performance or not and if I would lose any hp compared to Stage 1.

I had dyno'd my car before on the same dyno with similar conditions around 90 degrees with fuel from the same gas station.

ALL RUNS DONE ON California 91 Octane

Blue line - Stock Map + BSH Race Intake
Red line - APR Stage 2 + BSH Race Intake + USP catless Downpipe w/Bmw Cat




Blue line - APR Stage 1 + BSH Race Intake
Red line - APR Stage 2 + BSH Race Intake + USP catless Downpipe w/Bmw Cat




Here is a video of a pull... Nothing special.


 
P

plac

Guest
pretty good gains for stage 2, 10whp/15wtq.. thats actually a lot when you compare to what other cars would get with an exhaust pipe.
 
S

SFvalleyGTi1

Go Kart Champion
plac said:
pretty good gains for stage 2, 10whp/15wtq.. thats actually a lot when you compare to what other cars would get with an exhaust pipe.
Click to expand...


Ya gains are decent... Wish I would've dyno'd when it was catless. I came across a dyno of a Evo X comparing a 100 cell cat to a test pipe... That alone made a ~16whp difference! The Bmw cat I put on I believe is 400 cell count.

I'm debating whether to get a 100 cell and a resonator and remove the Bmw cat OR just get a Meth kit and run 100 octane tune daily. The car also needs to be slammed... At the local GTG they call my car "baby tiguan"

**10whp and 16wtq ;)
 
jorgeecolina

jorgeecolina

Banned
:thumbsup:
 
S

SFvalleyGTi1

Go Kart Champion
Comparing my dyno numbers to what APR's website says....

10% drive train loss is what APR uses to calculate their crank hp.

My Car's Stage 2 with 91 oct. Crank number: 260hp 297tq
APR's rated Crank numbers for Stage 2 with 93oct.: 273hp 313wtq

Not really an accurate comparison I THINK because they use a different dyno.
 
D

DDGTI

Ready to race!
Looks great; nice healthy gains all the way through the powerband. Going from catless to 300 cell cats on my e92 M3 made an 8 whp difference in peak numbers. However, it lost as much 12 under the curve in some areas. If you're using the secondary cats off of your 335 then you probably aren't losing a lot of power. BMW's 400 cell secondary cats actually flow really well.
 
S

SFvalleyGTi1

Go Kart Champion
DDGTI said:
Looks great; nice healthy gains all the way through the powerband. Going from catless to 300 cell cats on my e92 M3 made an 8 whp difference in peak numbers. However, it lost as much 12 under the curve in some areas. If you're using the secondary cats off of your 335 then you probably aren't losing a lot of power. BMW's 400 cell secondary cats actually flow really well.
Click to expand...


From what I've heard NA motors need back pressure, where was with any FI car you want the least amount of back pressure possible. Below is a dyno of a Evo X, dotted lines is with catless, solid lines are with 100 cell cat. That car lost 5whp and 11wtq when it used the 100 cell cat.





BMW 400 cell cats flow well? I thought all 400 cell cats would flow the same... I read online that a 200 cell cat only flows about 15% more than a 400 cell cat. I'm hoping a 100 cell cat would flow 25% more than a 400 cell cat. Maybe that would give us an extra 10whp and 10wtq?
 
DBESTGTI1

DBESTGTI1

Go Kart Champion
No car needs back pressure, back pressure is a bad thing under all circumstances. Most people have no concept about back pressure is, it's resistance to flow. When people "lose power from not having back pressure" they are wrong, they loosing power because they have no exhaust gas velocity because its a poorly designed setup
 
S

SFvalleyGTi1

Go Kart Champion
DBESTGTI said:
No car needs back pressure, back pressure is a bad thing under all circumstances. Most people have no concept about back pressure is, it's resistance to flow. When people "lose power from not having back pressure" they are wrong, they loosing power because they have no exhaust gas velocity because its a poorly designed setup
Click to expand...

You're right, I used wrong wording... So you think a 2.5" exhaust would make more power because it has more velocity than a 3" exhaust?


Anyone care to explain why APR's site shows a delta of 79hp and 97tq between a stock car and Stage 2, but my car only made 32hp and 49tq difference? Am I missing something?

 
H

hobbes

Ready to race!
APR's numbers are at the crank. If you factor in drivetrain losses, your numbers are pretty close.
 
D

DDGTI

Ready to race!
The shape of the actual cats has as much to do with performance as the cell count. That's why Akrapovic 100 cell cats don't make any additional power over HJC 200 cell cats.
 
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