help! my car got upgrades but got slower...

**mianol** · 06-26-2008 02:15 AM

i put an ATP 3" cat delete dp with APR stage 2+
and in low revs the cars seems slower than before im thinking
it could be a result of lost of back pressure.Could that be the case? if so what can i do? if not what would be causing this? up until 3k it just seems slow
help appreciated

**InTTruder** · 06-26-2008 03:14 AM

Originally Posted by mianol

i put an ATP 3" cat delete dp with APR stage 2+
and in low revs the cars seems slower than before im thinking
it could be a result of lost of back pressure.Could that be the case? if so what can i do? if not what would be causing this? up until 3k it just seems slow
help appreciated

Less back pressure= less torque in some pump/pipe combinations. More flow, and better HP eventually. Should spin faster, so get up "on the pipe" as we used to say in 2-cycle days.

**kwanja_a3** · 06-26-2008 10:17 AM

Originally Posted by mianol

i put an ATP 3" cat delete dp with APR stage 2+
and in low revs the cars seems slower than before im thinking
it could be a result of lost of back pressure.Could that be the case? if so what can i do? if not what would be causing this? up until 3k it just seems slow
help appreciated

That's just it Vince, the larger diameter DP reduces pressure, slightly lowering your low end torque, but is increasing the overall HP band across all RPM, especially in the upper RPM.

I felt the same thing when I first switched to 3" TBE.

It's not so bad, less wheel spin, harder and longer pulling at higher speeds

**mianol** · 06-26-2008 10:53 AM

its not so bad....but it feels so wierd!!!
cuz of this ive stopped myself from getting a catback thinking i might just loose even more pressure freeing up the whole pipe....should i get one ? lol

**Jibberific** · 06-26-2008 12:12 PM

damn, my cat is shot so i have been looking into getting a test pipe.. but this is kind of unsettling to hear about.

**Meesh** · 06-26-2008 11:15 PM

did you upgrade your fuel pump with the stage 2+??

that might be an issue.

**a4rings** · 06-27-2008 02:11 AM

Originally Posted by Jibberific

damn, my cat is shot so i have been looking into getting a test pipe.. but this is kind of unsettling to hear about.

easy answere= smaller diameter dp

**Jibberific** · 06-27-2008 03:43 AM

I have been looking around and all the good name brand test pipes are 3 inches. The only place i can find 2.5 inch test pipes is ebay.

I have a 2.5" magnaflow exhaust without resonators and chipped k03. do you think i will lose too much backpressure with this combo if i go for a 3 inch test pipe?

**mike-2ptzero** · 06-27-2008 08:18 AM

Have to also remember since the turbo is a internal WG, so when you decrease the back pressure behind the turbo outlet you also decrease the resistance at the WG flap which means now more exhaust gas will follow that path vs going thru the exhaust wheel. This is one of the reasons you feel a decrease in low end tq since the turbo is taking slightly longer to spool up.

The TP from Eurocode is 2.5", if you guys want one let me know and maybe I can get a better price.

What size is the ID (inner diameter) of the EuroCode Tuning TestPipe?
Our TesPipe starts off at the back of the turbo with a 2.75" ID and transitions to 2.5" ID down at the factory downpipe flange.

**Panzr15** · 07-14-2008 11:30 AM

This is probably a noob question, but do I have to chip my car to run a test pipe or can run stock with out throwing codes??

**Killerteve** · 07-14-2008 03:25 PM

A test pipe on stock tuning WILL cause a CEL. Even with a chip you will need a extra file to prevent CEL's as your ECU needs to know there is not cat.

**Panzr15** · 07-14-2008 03:39 PM

Originally Posted by Killerteve

A test pipe on stock tuning WILL cause a CEL. Even with a chip you will need a extra file to prevent CEL's as your ECU needs to know there is not cat.

Thanks