TrueBendz Turbo-Back Exhaust System

[tom-t-rifik]

I've been watching the TrueBendz site for some time and they now have their 2-1/2" & 3" Turbo-Back Exhaust sytems available; new downpipe aluminized or stainless steel tubing with Magnaflow's Wide-Open Cat, Resonator and Muffler.

My questions are: has anyone installed one? and which one would be best for stock turbo and stage 1 turbo. I know the original specs on the Stage 1 & 2 kits called for maximum performance with a 3" exhaust system, but would the 3" be overkill for a stock turbo? I ran 2-1/2" Borla Duals with a Hedman Header on my non-Turbo 2002 PT and it ran terrific!

What makes me question is an article I just read on an SRT-4 Stage II installation using MaxxFabs 3" downpipe and modified Borla exhaust. They had problems with the PCM going haywire and over-adjusting the mix to compensate for the better flow of the larger tubing and exhaust.

Suggestions?

[hyracer]

No exhaust upgrade is required for Stage 1 and Mopar requires the 2.5" Mopar/Borla cat-back system to achieve advertised HP ratings for Stage 2.

Unless your going to buy a larger turbo in the future a 3" cat-back system would be over-kill, in fact as you indicated some of the SRT4 group are reporting a loss of low end HP and torque with the 3" system.

Deen

[JohnM]

There's a few of us on this forum with 3.0" downpipe and cat and the 2.5" catback system. (Maxxfab and Mopar respectively for me) I had this setup before, and now with Stage 1. It works great either way - there is absolutely no downside in my experience. I just can't believe how quick my car is in real-world driving situations. I haven't had any chance meetings with ricers at appropriate stop lights lately, but I'm always looking. In reality I've rarely even gone to WOT since I've had stage 1.

There were earlier postings here, with 3barboost included, that have discussed that, with a turbo, dropping backpressure as low as possible is advantageous and does not carry the loss of low end torque like with normally asperated engines.

[RallyDRock]

with a turbo car you really need the least restrictive exhaust.
a 3" cat back is useless without a 3" DP and 3" cat
the loss of low end hp+torque? dyno or seat of pants i'd be interested in those graphs
if you want low end power get a tractor, turbos are for 3K rpm-up

[Ant]

Generally speaking the less restrictive exhaust (3") in combination with a turbo setup works great, especially in our HRC aftermaket turbo systems.It is not quite as cut and dry. On a newer car, with a factory turbo, the computer likes to take over and could at times have adverse effects.
If you put a 3" exhaust on a stock GT in an area where only 91 octane is available, there is a possibility of losing power. With less back pressure the boost level wants to increase. With increased boost levels and crap gas there is a greater chance for detonation. The computer now wants to keep everything safe and pull back timing and possibly your boost levels in the higher RPM range. So you may get that initial boost spike then the car can fall flat on its face. It is a good idea to have supporting mods for the large 3" exhaust; Stage 1 (2) computer, map clamp, larger injectors, etc.
The Staged computer should provide more aggressive boost and timing maps to allow for more power and not get "scared" like the girly stock electronics.

[R3dWhitNCrz]

I'm learning so much just going through these pages. I am in the process of upgrading my exhaust. ANT- my system is the watered down version of yours, I was thinking going 2.5, did you start small and get bigger or did you go straight to the 3"?
I know we have written each other before...where are you located? Do you go to alot of events? Sounds like your PT is a beast! I know how mine feels and yours is SUPERSIZED!!!

[Ant]

quote:Originally posted by R3dWhitNCrz

I'm learning so much just going through these pages. I am in the process of upgrading my exhaust. ANT- my system is the watered down version of yours, I was thinking going 2.5, did you start small and get bigger or did you go straight to the 3"?
I know we have written each other before...where are you located? Do you go to alot of events? Sounds like your PT is a beast! I know how mine feels and yours is SUPERSIZED!!!

Not trying to hi-jack a thread here but:
I had the Borla 2.5" cat-back previously which I was very happy with. I am putting 238 hp to the wheels now with 8-9psi. I am in the process of installing the Crane ignition with timing retard and am expecting my water/alcohol injection kit any day. This should allow me to run higher boost, 12-16 psi and get me close to 300 hp. With my goals I require a 3" exhaust.
I am in AZ and attend a few events.
I will be going to the track in Oct so I will post times. I am also trying to find a backup tranny right now sinve i am running the infamous 41TE.

[R3dWhitNCrz]

I imagine that the 2.5 you have is dual exhaust!?? I really want single but if I can't find what I want I will drop you another note. BTW, how much would you let it go for?? Thanks for such speedy reponses. I travel alot to Arizona, what part are you in? I have been coming to Tempe, Phoenix area when I visit. thanks again.

[tom-t-rifik]

My thanks to everyone! This is exactly what I wanted to know and I really appreciate the discussion pros & cons. By the way Ant, I'm in Arizona myself. If any of you guys will be traveling in the Phoenix area, drop me a line. We've got something going almost every weekend (3 local PT Cruiser Clubs). I'd love to meet any one of you and talk PT's over a burger and brews! thomas981@earthlink.net

[Ant]

I am in Peoria, north west of Phoenix, but not far.
I sold my Borla duals already.
Tom, I work odd hours and have a hard time catching up with you guys. I am usually off on Sundays. Let me know if you ever do anything on that day.
Thanks

Anthony