05fastblk

So i got my headers installed yesterday. I can feel some major power but the car feels a little odd, like it has a bigger lag than normal and its like you have to give it alot of gas while taking off or else it stutters and kind of jerks. Anyways I emailed Dave at brenspeed and asked if I needed a new tune or if its best to dyno tune this is what he said. let me know what you think, I am almost sure its not normal as I have installed headers on two other vehicles (350z and gmc truck)

any info will be great!

"Our tuning is light years ahead of 99% of any other "local" tuning places. There is only a couple places in the world tuning at this level. There is no need for any revisions or anything for those parts. You will see no improvement strapping the car on a dyno....even if it were our dyne right here at our shop. We have literally done THOUSANDS of these cars with your exact mods and that is how we offer such accurate mail order tuning. There is nothing I would change in the tune for your parts, any loss you are feeling is most likely false feelings. I can assure you there should have been a good midrange power gain with no loss down low. We have seen it on the dyno and at the track sops so many times. Your tune is perfect."
----- Original Message -----

Tylus

yes, with Long Tubes you should be getting your tunes adjusted.

the LT's move the location of the O2 sensors. this causes the pulse timing to be off, which will cause the motor to act funny and hesitate. so unless the O2 bungs are in the same spot, the tune needs to be addressed so the PCM knows the proper pulse timing and can react accordingly.

not to mention the increased exhuast gas flowrate

did you keep the rear sensors and use extensions? or use mil eliminators?




if that blurb is from the tuner...wow. very full of himself. kinda annoying to me

05fastblk

same thing I thought!the o2 sensors are furthur back than oem and yes I thought the same thing, I am almost tempted to ditch brenspeed and seek info somewhere else.. No disrespect to what brenspeed has but the issue is obvious to a person who is NOT a professional (me) and I was 99.9% sure it wasnt normal, i have drivin this car for almost 3 years and he is telling me its perfect! c'mon. I heard about loosing some low end HP and Torque but the car seems like its a v6 then at 3k rpm turns into a V8 lol.

Tylus

alot of guys have issues with LT's on these cars. if you do a search of the forum you can see some of the things guys go through.

usually guys have MIL and CEL issues. some poor bastards can't ever get their "custom mail ordered" tunes correct and have to live with a CEL. About the only 100% fix is Dyno tuning where the tuner can see exactly what is happening as it occurs.

I have no personnal experience with Brenspeed, but they have earned the reputation they have. You should call them up and express your concerns. Having a guy tell you that you are imagining the loss of power and wierd running problems is not correct

siggyfreud

What?

Under normal driving conditions the response from the O2's to the engine is still way faster than what you could feel.

Under WoT conditions cars run in Open loop, which means they aren't taking feedback from the O2's.

Butt dynos are more a perception of sound than they are of speed. It's very possible that the LT's simply shifted your power UP a few hundred RPMS in powerband.

onederful100

i used the canned tune from my livewire to simply turn off the rear O2 sensors and did not have any custom or dyno tunes, and my car ran just fine like that for almost a year until i went FI.

but, every car may be a little different. how long have you had the tune? if not for too long, give it a while.

Tylus

see bold above

05fastblk

yes, I feel the power but it feels like the throttle gets stuck at 2k rpm and jerks unless I get on it harder, which then causes the car haul *** lol.the CEL has not turned on and I am not running cats

StowesStang

When I bought my BBK LTs, we installed the MIL eliminators and YES, YES, the car went straight to the Dyno to have the tune adjusted.............. ITS A MUST!!!! No problems here and have a stout running and sounding machine!!!!

808muscle

I would definatly call brenspeed and talk to a tech. Forget email responses. No that it matters but what brand of headers did you install?

I just installed LTs too, I hope I dont have this issue as well. Have not driven though.....got a rear piping issue.

Good luck and post up how it turns out.

patrick