HEADER INSTALL AFTERMATH

rory kurtz

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I installed kooks long tubes with off road H pipe last week and love them. Prior to install the vehicle only had JLT
CAI and a Lund tune. I was told there is no revision for the tune after installing the headers.
I have been hesitant to step on the gas however. The car seems to be running fine but I noticed that when I did go maybe 70% throttle, the factory boost gauge was reading 19lbs by 5000 RPMs. Is the factory gauge reliable? Has anyone else experienced anything like this? Is there possibly another issue or am I just being paranoid? Any input is greatly appreciated.

Thanks
 

NoSlowGT

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For what these cars are worth, engines alone, get another tune just to be sure. Most tuners only charge a fraction of the original cost for a re-tune.
 

Norton

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I installed kooks long tubes with off road H pipe last week and love them. Prior to install the vehicle only had JLT CAI and a Lund tune. I was told there is no revision for the tune after installing the headers. I have been hesitant to step on the gas however. The car seems to be running fine but I noticed that when I did go maybe 70% throttle, the factory boost gauge was reading 19lbs by 5000 RPMs. Is the factory gauge reliable? Has anyone else experienced anything like this? Is there possibly another issue or am I just being paranoid? Any input is greatly appreciated.
The answer to your first question is the factory boost gauge is NOT reliable. IIRC, it used some kind of computer-based calculation to estimate boost level. It wasn't tremendously accurate when you were stock. It's inaccuracies were probably amplified when you modded. If you want to know what's really happening, install a dedicated boost gauge with a proper sensor. Another, even more critical, value to monitor is AFR. The factory wideband sensors are good, but you'll need something to extract the info they provide from the ECU and display it for you. There are probably many options, but I used an Aeroforce Interceptor before transitioning to an nGauge when I went with an aftermarket tune a few years ago.

FWIW, I agree with @NoSlowGT - I'd talk with my tuner about an update for the exhaust change. If anything, headers should allow the car to breath more easily, reducing (rather than increasing) boost. Breathing better, however, comes with the possibility of leaner AFRs which can damage the engine.
 

rory kurtz

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For what these cars are worth, engines alone, get another tune just to be sure. Most tuners only charge a fraction of the original cost for a re-tune.
The answer to your first question is the factory boost gauge is NOT reliable. IIRC, it used some kind of computer-based calculation to estimate boost level. It wasn't tremendously accurate when you were stock. It's inaccuracies were probably amplified when you modded. If you want to know what's really happening, install a dedicated boost gauge with a proper sensor. Another, even more critical, value to monitor is AFR. The factory wideband sensors are good, but you'll need something to extract the info they provide from the ECU and display it for you. There are probably many options, but I used an Aeroforce Interceptor before transitioning to an nGauge when I went with an aftermarket tune a few years ago.

FWIW, I agree with @NoSlowGT - I'd talk with my tuner about an update for the exhaust change. If anything, headers should allow the car to breath more easily, reducing (rather than increasing) boost. Breathing better, however, comes with the possibility of leaner AFRs which can damage the engine.
I agree with that and figured a retune would be necessary but I was told by Lund that there is no tune revision with the long tube headers. I currently have a SCT X4 programmer. I believe I can use that to datalog.
 

sleek98

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The ONLY thing to change is the o2 delay, since your 02 sensor is no a touch farther back in the pipe, but its a learned parameter so it really doesn't have to be changed.

Extra air coming in from it breathing easier is measured on via the MAF. As long as you are not at the very top of the MAF curve it will just read the next cell up and fuel just fine. With a JLT the maf curve should get you well past where you are making.

They used to turn off cels and rear 02s, but no longer do that.
 

tampasnake

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Lund may not be allowed to state he does tunes for long tube headers and especially headers with no cats after the recent visit of his business by the Feds.
They released a video on YouTube the other day talking about it.
 

darksykal

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The boost gauge on these cars are a complete joke.
mine reads 21 PSI and on the dyno I peaked at 17.2 PSI

with that said, i'd def get another tune after a header install regardless. my tuner said it's required.
 

69b302

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The tuners are suppose to tune, not let the computer eventually adjust. Most tunes have the O2 heater and delays tweaked for headers.
 

CobraBob

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The answer to your first question is the factory boost gauge is NOT reliable. IIRC, it used some kind of computer-based calculation to estimate boost level. It wasn't tremendously accurate when you were stock. It's inaccuracies were probably amplified when you modded. If you want to know what's really happening, install a dedicated boost gauge with a proper sensor. Another, even more critical, value to monitor is AFR. The factory wideband sensors are good, but you'll need something to extract the info they provide from the ECU and display it for you. There are probably many options, but I used an Aeroforce Interceptor before transitioning to an nGauge when I went with an aftermarket tune a few years ago.

FWIW, I agree with @NoSlowGT - I'd talk with my tuner about an update for the exhaust change. If anything, headers should allow the car to breath more easily, reducing (rather than increasing) boost. Breathing better, however, comes with the possibility of leaner AFRs which can damage the engine.
This (EXCELLENT by the way).....

Lund may not be allowed to state he does tunes for long tube headers and especially headers with no cats after the recent visit of his business by the Feds.
They released a video on YouTube the other day talking about it.
.....and this!
 

gimmie11s

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How much boost was the factory gauge reading before the headers? LT's are usually good for about 2psi drop.
 
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Jam421

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Boost gauge on my '13 pins at WOT. On the dyno it pulled 16.5psi boost. Without reagrd for the factory boost gauge ....since you have an SCT it's likely not a bad idea to data log different types of pulls at specific rpm's for Lund to review each submittal. They only charge $50 for log reviews for possible revisions. Maybe we were all naive but none of my buddies who did header upgrades did so without a dyno review/tweak.
 

biminiLX

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Great to question these things but if you’ve committed to modding it to this level, you really need to learn to datalog.
There are several online tutorials on SCT datalogging with your X4 direct from Lund Racing and Alex Flores You Tube.
In general all points above have been touched and you don’t really need a tune revision for exhaust mods but I’d definitely check the datalog.
Great mods should be fun, good luck.
-J
 

WicK

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Great to question these things but if you’ve committed to modding it to this level, you really need to learn to datalog.
There are several online tutorials on SCT datalogging with your X4 direct from Lund Racing and Alex Flores You Tube.
In general all points above have been touched and you don’t really need a tune revision for exhaust mods but I’d definitely check the datalog.
Great mods should be fun, good luck.
-J
Perfect! So when I change my clutch I can goto long tubes and cats lol
 

2011 gtcs

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Great to question these things but if you’ve committed to modding it to this level, you really need to learn to datalog.
There are several online tutorials on SCT datalogging with your X4 direct from Lund Racing and Alex Flores You Tube.
In general all points above have been touched and you don’t really need a tune revision for exhaust mods but I’d definitely check the datalog.
Great mods should be fun, good luck.
-J
I'm sure you've seen, but if anyone is tuned with Lund and uses SCT better finsh everything up by the 15th. After that no more SCT tuning from Lund. Only nGauge and RTD.
 

biminiLX

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I'm sure you've seen, but if anyone is tuned with Lund and uses SCT better finsh everything up by the 15th. After that no more SCT tuning from Lund. Only nGauge and RTD.
Yeah, all my stuff is on HPTuners now anyway, but the new changes suck. EPA on small volume hot Rodders is pointless in big picture.
-J
 

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