Xpipe and Catback--make a car richer vs stock exhaust

[broke7]

I just installed my UPR Offroad X and MAC 3" catback. My dynorun with my stock Hpipe and straightpipes I was a tad rich from 5000+ down in the 10.5:1 range.

I noticed the TQ loss right off the bat with this new exhaust setup. My question is, do I need a re-tune, I would think the car richened up some from flowing alot better and not being as bottlenecked.

I know on ls1's when you install longtubes, they richen up bigtime and need to be leaned out, wonder if it applies here?

 

[broke7]

ttt

 

[11secCobra]

reburn will help get back some torque that u lost with the free flowing exhaust

 

[DSG03Snake]

Not sure if you need a reburn since I never chipped my car, But when I had the X and Catback on it took about 3 drivecycles for my 'low end power' to come back, then it felt much better then stock.

But w/o cats you are prolly gonna feel a lot of low tq loss without a reburn I would imagine, because it flows SO much more.

Btw, nice times!

 

[Andorion]

How would the low end torque at WOT "come back" after any amount of time?

~Berj

 

[Poisonous Mods]

Hey Allan,
Might want to call Rick?
I know when i lost the TQ, my tuner did over 13 runs to get it back & some. 13 runs

I know he was burning that chip so many freaking times. Last one did it since he waited for 15mins before he did the run.

U can def. get it back but not sure if its Richer or Leaner as your questions ask's :shrug:

 

[broke7]

I should be able to make a pull later this week, and see wtf is going on.

 

[Shadowgray03]

Originally posted by broke7
I just installed my UPR Offroad X and MAC 3" catback. My dynorun with my stock Hpipe and straightpipes I was a tad rich from 5000+ down in the 10.5:1 range.

If your using a tail pipe sniffer and you went to an offroad x-pipe you dont have cats burning off extra fuel so of course it will show richer. The EEC will adust the short term fuel trims over time and they will in turn become the long tem fuel trims and power will come back. On open loop (ie WOT) the EEK isnt using the O2's for feedback but I beleive it still using the fuel trim tables.

 

[broke7]

Nice explanation, that is along the lines of what I was looking for. I know a little about Ltrims and short trims.

Im just wondering, if the new setup is out of the range of the trim capabilities.