LT Headers Low-Mid Range Power Loss

[spoole96]

Is anybody noticing any low to mid RPM range power loss or lag after installing LT headers with an updated tune? I have been working with my tuner. But, I still notice some lag or power loss in the 2k-3.5k RPM range. My tuner told me:

" I have made some changes to the Ti-VCT settings, which will help a little but we have noticed some power loss with long-tubes in the mid-range. Please use these files and let me know how it feels"

I'm still working with the tuner. I've datalogged once already. And I'll probably datalog again. I'm just curious if anybody else is having any issues. It very noticeable for me since this RPM range is normal driving. Over 4k RPM feels very strong though.

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[anotherneon]

Is anybody noticing any low to mid RPM range power loss or lag after installing LT headers with an updated tune? I have been working with my tuner. But, I still notice some lag or power loss in the 2k-3.5k RPM range. My tuner told me:

" I have made some changes to the Ti-VCT settings, which will help a little but we have noticed some power loss with long-tubes in the mid-range. Please use these files and let me know how it feels"

I'm still working with the tuner. I've datalogged once already. And I'll probably datalog again. I'm just curious if anybody else is having any issues. It very noticeable for me since this RPM range is normal driving. Over 4k RPM feels very strong though.

What tuner? And what gear? My car always felt faster in 4k than it did at 2-3.5k, because youre in the meat of the power band.

 

[LethalPerformance]

Is anybody noticing any low to mid RPM range power loss or lag after installing LT headers with an updated tune? I have been working with my tuner. But, I still notice some lag or power loss in the 2k-3.5k RPM range. My tuner told me:

" I have made some changes to the Ti-VCT settings, which will help a little but we have noticed some power loss with long-tubes in the mid-range. Please use these files and let me know how it feels"

I'm still working with the tuner. I've datalogged once already. And I'll probably datalog again. I'm just curious if anybody else is having any issues. It very noticeable for me since this RPM range is normal driving. Over 4k RPM feels very strong though.

Are you basing this off of just feel or have you verified this on an actual dyno?

 

[spoole96]

What tuner? And what gear? My car always felt faster in 4k than it did at 2-3.5k, because youre in the meat of the power band.

Tuner doesnt matter at this point. I didnt want to get on here and start bashing or creating a bad name for the tuner.


Any gear. I have a GT 6M w/ PP. Its most noticeable in first, second, & third during normal driving.


Of course the car is faster at higher RPM's. But I am specifically talking about normal driving range RPM's (1500-3500). The car feels a bit less powerful at low to mid RPM's. The tuner said these cars are loosing some torque in the low to mid RPM range with long tube headers. Its not that bad. But, I can definitely notice it. Just wondering if anybody else that has installed a set of LT headers on an S550 GT and noticed these same issues?

 

[spoole96]

Are you basing this off of just feel or have you verified this on an actual dyno?

I dont need to put it on a dyno to feel the difference. If I lived closer to the tuner I would have it dyno tuned for sure.

 

[Grimace427]

Are you basing this off of just feel or have you verified this on an actual dyno?

+1 You need an actual dyno graph to verify changes in the powerband. I've seen a lot of people complain about loss of torque when going to longtube headers or off-road midpipes, and it turns out they didn't actually lose torque but rather the now much louder exhaust made it seem like they need to press the throttle more to achieve the same acceleration.

 

[LethalPerformance]

I dont need to put it on a dyno to feel the difference. If I lived closer to the tuner I would have it dyno tuned for sure.

How are you supposed to verify hp/torque loss without putting it on a dyno?

 

[anotherneon]

+1 You need an actual dyno graph to verify changes in the powerband. I've seen a lot of people complain about loss of torque when going to longtube headers or off-road midpipes, and it turns out they didn't actually lose torque but rather the now much louder exhaust made it seem like they need to press the throttle more to achieve the same acceleration.

Yep! After my header install I thought I was going much faster than I was. Your mind associates the loud sound with speed. OP are you talking about part throttle power at that RPM?

 

[anotherneon]

How are you supposed to verify hp/torque loss without putting it on a dyno?

Butt dyno!

 

[LethalPerformance]

Butt dyno!

LOL.. Yeah those are real accurate.

 

[bobc775]

I had my log tube headers installed today. I added a tune for headers before I left the shop. I too felt like I had lost a lot of low end to mid range torque. Rough idle and I kept waiting for it to die. I wasn't sure I was going to make it home... When I got home I loaded the original tune (before header) and the car actually seemed to run better. More throttle response and smoother acceleration. Go figure.

Yes it is much louder to the point I'm not sure they will stay especially if it seemingly runs weaker. As to having to dyno I'm not sure why I'd be using a tuner if I need to dyno changes I make??

 

[stoli]

Put it in track mode and then see if you notice a difference at lower rpms. It seems the nanny controls/throttle response gets messed with, especially when in normal mode. I could be completely wrong, but it sure seems this way for me.

 

[1320']

LOL.. Yeah those are real accurate.

I have found that attractive female butts are the most accurate. That is why I enjoy having them in my car as often as possible, for research purposes you see

 

[Agent_Kay]

+1 You need an actual dyno graph to verify changes in the powerband. I've seen a lot of people complain about loss of torque when going to longtube headers or off-road midpipes, and it turns out they didn't actually lose torque but rather the now much louder exhaust made it seem like they need to press the throttle more to achieve the same acceleration.

Funny you say that. I thought I was going crazy over here too. I have SW LT with QTP electric cutout set up. The cutouts are located in front of the stock resonator and muffler. With the cutouts open I felt it was slower than with it closed but the dyno showed a 10 hp increase with it open.

 

[spoole96]

Put it in track mode and then see if you notice a difference at lower rpms. It seems the nanny controls/throttle response gets messed with, especially when in normal mode. I could be completely wrong, but it sure seems this way for me.

I keep it in sport mode. I have tried it in normal mode though and it all felt the same. Track mode not sure though. I don't put it in track mode unless I'm gonna break traction. It's seem to be noticeable at part throttle. I did some more data logging today. When I get back in town I'm gonna email the tuner the logs and hopefully get this worked out.

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