Tune required when installing longtube headers?
Thread Starter
Instructor
Joined: Jan 2020
Posts: 143
Likes: 12
From: Beaumont, Southeast Texas
Tune required when installing longtube headers?
I put long tube headers and a catalytic X-Pipe on my otherwise stock LT1 engine. It’s popping and sputtering once the engine starts to warm up a little and is basically undriveable. I took it down to the dyno for a retune and he said that it’s an installation issue, the tune won’t be that far off. He said the car should be be drive able and not need retuning. Does an otherwise stock engine need to be retuned, and it’s not driveable if not? Or do I have an installation problem? Which would be with the O2 sensors.
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Joined: Oct 2004
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From: Manassas Park VA
St. Jude Donor '07-'08,-'13-'14, '16-'17
I put long tube headers and a catalytic X-Pipe on my otherwise stock LT1 engine. It’s popping and sputtering once the engine starts to warm up a little and is basically undriveable. I took it down to the dyno for a retune and he said that it’s an installation issue, the tune won’t be that far off. He said the car should be be drive able and not need retuning. Does an otherwise stock engine need to be retuned, and it’s not driveable if not? Or do I have an installation problem? Which would be with the O2 sensors.
and
Then RUN like Hell
You need a Tune with LTH...
Regards
Chip
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Burning Brakes
Joined: Sep 2019
Posts: 928
Likes: 615
From: Navarre, Florida
Here's my take on it--any time you mess with the air/fuel ratio of the vehicle by changing parts that impact it, you should get a tune/retune. Sure, you could drive the vehicle with longtubes and no tune but, it doesn't mean that you should. To me, committing to putting longtube headers on a car is also committing to getting it tuned. There's an old adage that tends to be overlooked these days; just because you can, doesn't mean you should. Get the install issue squared away and then get it tuned.
Le Mans Master
Joined: Oct 2014
Posts: 8,673
Likes: 2,727
From: Atlanta GA
You car will run without a tune , you will be leaving a lot of power on the table but .....
You will have a CEL for the rear O2 sensors but as said above the most common mistake the O2 sensors are plugged in wrong , the right is on the left and the left is on the right or …… you have a exhaust leak , retorque all the header to head bolts or … you somehow damaged the O2 sensor
Dave
You will have a CEL for the rear O2 sensors but as said above the most common mistake the O2 sensors are plugged in wrong , the right is on the left and the left is on the right or …… you have a exhaust leak , retorque all the header to head bolts or … you somehow damaged the O2 sensor
Dave
Race Director
Joined: Mar 2001
Posts: 19,964
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From: Bonneville Salt Flats
A tune would be desirable, as noted, to maximize the results. However, something has been f**ked up during the installation process. Yes, it IS an installation problem. Others have suggested where to start your diagnostics. Btw, has it set any CELs (seems you would have noted them, if it had)? All the best. 
Burning Brakes
Joined: Aug 2009
Posts: 770
Likes: 164
From: Southeastern NM
I installed long tube headers with off road x pipe and a k&n cai on my 2014 Z51. It ran flawlessly and when I went in to get a tune, it only picked up 3 hp and 3 tq. Nothing major was changed. A tune is optional, but not required. As far as HUGE gains, not a chance, unless the dyno shop is fudging numbers for advertisement purposes (which is what I see a lot of on here).
Le Mans Master
Joined: Oct 2014
Posts: 8,673
Likes: 2,727
From: Atlanta GA
I installed long tube headers with off road x pipe and a k&n cai on my 2014 Z51. It ran flawlessly and when I went in to get a tune, it only picked up 3 hp and 3 tq. Nothing major was changed. A tune is optional, but not required. As far as HUGE gains, not a chance, unless the dyno shop is fudging numbers for advertisement purposes (which is what I see a lot of on here).
Dave
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Burning Brakes
Joined: Aug 2009
Posts: 770
Likes: 164
From: Southeastern NM
Mine stock it was at 403 rwhp.
I added long tubes and a k&n cai and went in for a tune. The A6 put down 444 rwhp.
Then, I got it tuned and it only picked up 3 hp and 3 tq for a total of 447 rwhp.
Burning Brakes
Joined: Aug 2009
Posts: 770
Likes: 164
From: Southeastern NM
Mine stock it was at 403 rwhp.
I added long tubes and a k&n cai and went in to put it on dyno before tuning. The A6 put down 444 rwhp.
Then, I got it tuned and it only picked up 3 hp and 3 tq for a total of 447 rwhp. Basically, a 44 HP increase over stock (not too shabby).
I drove my car around for quite a while with the mods prior to tuning, so the LTFT's probably tuned the car on its own, lol. Remember, we're talking LT1 here, not my C7 Z, that's a whole diff ballgame there
Last edited by GeorgeR_Zed06; Feb 17, 2020 at 06:19 PM.
Le Mans Master
Joined: Oct 2014
Posts: 8,673
Likes: 2,727
From: Atlanta GA
No, let me clarify that, lol!
Mine stock it was at 403 rwhp.
I added long tubes and a k&n cai and went in to put it on dyno before tuning. The A6 put down 444 rwhp.
Then, I got it tuned and it only picked up 3 hp and 3 tq for a total of 447 rwhp. Basically, a 44 HP increase over stock (not too shabby).
I drove my car around for quite a while with the mods prior to tuning, so the LTFT's probably tuned the car on its own, lol. Remember, we're talking LT1 here, not my C7 Z, that's a whole diff ballgame there
Mine stock it was at 403 rwhp.
I added long tubes and a k&n cai and went in to put it on dyno before tuning. The A6 put down 444 rwhp.
Then, I got it tuned and it only picked up 3 hp and 3 tq for a total of 447 rwhp. Basically, a 44 HP increase over stock (not too shabby).
I drove my car around for quite a while with the mods prior to tuning, so the LTFT's probably tuned the car on its own, lol. Remember, we're talking LT1 here, not my C7 Z, that's a whole diff ballgame there
The real measurement is the 1/4 mile ....
Dave
Burning Brakes
Joined: Aug 2009
Posts: 770
Likes: 164
From: Southeastern NM
Lol .... and you have to also take into account different days , different temperatures, different DA and all the other variables. The only way to compare apples to apples would be to do a baseline then do the mods all on the same day and even then there will still be some variability
The real measurement is the 1/4 mile ....
Dave
The real measurement is the 1/4 mile ....
Dave
Le Mans Master
Joined: Oct 2014
Posts: 8,673
Likes: 2,727
From: Atlanta GA
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^ THIS ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^
Dave