I just installed a Riss Racing Catless DP and have a feeling, in the butt dyno, that I lost some torque down in the lower RPM range. The car is wicked fast now but the stock car, with the Alta Stage 1 map felt like it pulls harder than the Stage 2 map with new DP. I could be wrong, my ex-wife proved that to me many times, but am curious if the loss of some backpressure killed some torque. I didn't turbo cars applied to that philosophy.

 

you might have a boost or exhaust leak

 

According to the Accessport, 22.7 max PSI. Ran my hand around all pipe connections twice and felt no exhaust leak. It may just be in my head.

 

Try running car without your wife in it JK. Curious to see please post results if dyno

 

Depending what exhaust you are running...with an upgraded FMIC and catless DP you will get slightly slower spool up (we are talking a few hundred rpms at most) so this could be perceived as less torque at the same RPM. End result though would still be more power later especially if you are comparing 20mph-40mph pulls.

Not to mention our nation heat wave has turbo cars everywhere making just a little less power :-)

 

I am running the stock JCW exhaust. No FMIC installed yet, I will be putting the Helix in next week. Like I said, it may just be in my head cause gawd, this thing is fast.

 

No, you're not crazy. I experienced the same thing when I first installed my downpipe. It's almost as if the torque curve is slightly biased to higher engine speeds. After my ECU tune, it's definitely fixed, but adding a downpipe I feel has added more power/torque in the top end of the engine speed range. This doesn't neccessarily bother me since I track my car quite a bit. For the Auto-X'er this is not ideal.

 

The torque curve gets pushed to the right and up basically. So yes, you get a large increase in torque from the catless dp, but spool time is slightly increased so technically lower end boost is lower.

Also, did you install a new gasket on both ends when you installed the RR DP?
eg the turbo outlet which goes over the studs, and one between the DP and the catback...

Reusing these CAN cause leaks.. I originally only replaced the turbo one, and eventually found out the DP to CB Vband connection was leaking.