Shorty vs Long tube headers
#21
Race Director
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i run midlengths and E85 along with a couple other little things, just haven't had time to go to the track.
#22
The CEL can be avoided yes. But you are no longer running optimal timing and fueling at part throttle and you are leaving half of the power on the table at full throttle. But I can understand your reasoning. It's not like you will hurt the motor or anything so its not wrong per say to install long tubes without a tune.:
#24
Safety Car
Long tubes could be worth only 10hp over mid lengths
https://www.corvetteforum.com/forums...post1591696605
https://www.corvetteforum.com/forums...post1591696605
#25
Instructor
SHORTIES are best for idle - midrange power; where most folks drive.
LTs are best for the Track (mid-upper power)
It takes 20hp for the average joe to 'feel' it. A tuner, maybe less.
Personally, I'm looking at the TSP LTs with catted pipe; albiet shorties show me an interest in daily driving too... IDK
LTs are best for the Track (mid-upper power)
It takes 20hp for the average joe to 'feel' it. A tuner, maybe less.
Personally, I'm looking at the TSP LTs with catted pipe; albiet shorties show me an interest in daily driving too... IDK
Last edited by RobsCountach`; 05-14-2019 at 02:59 PM.
#26
Long tubes will give you the best sound and best potential for power - no question. There has been HUGE debates about which long tube headers produce the best outcome; ARH, Kooks, tri-y versions.... That was a holy war for awhile. It was resolved by a fairly comprehensive set of comparison dyno runs across the brands but, I have not seen the thread in a long time.
Mid-length will offer a very good bump, and NO its not less then half of long tubes when apples to apples (both header sets no-tune or both headers w/tune). These are mid-length not shorties. There has been enough posted dyno charts to prove that one out already. They WILL NOT provide the same as long tube. For raw performance you are better off with long tube, tuned or un-tuned but, maximized with tuned.
By the way, swapping stock x-pipe for off-road x-pipe improves sound and flow (24% better then stock) - but dyno's only showed .5 to .75 HP increase. Even with stock exhaust, swapping to an off-road x-pipe will change the sound a little bit. A little bit.
Mid-length - box stock - when run with high-flow cats - do not throw a code with out a tune. Meaning, it is arguable that changing to mid-length would not lead to harm with the powertrain due to a modification you did to the car. Long tube, box stock, throw a code and you need to get a tune to turn the CEL off, calibrate to the right settings to compensate, and you would need a tune to get the most from the change as well. Your not going to argue your way out of that one as easily from a warranty claim perspective.
Mid-length will offer a very good bump, and NO its not less then half of long tubes when apples to apples (both header sets no-tune or both headers w/tune). These are mid-length not shorties. There has been enough posted dyno charts to prove that one out already. They WILL NOT provide the same as long tube. For raw performance you are better off with long tube, tuned or un-tuned but, maximized with tuned.
By the way, swapping stock x-pipe for off-road x-pipe improves sound and flow (24% better then stock) - but dyno's only showed .5 to .75 HP increase. Even with stock exhaust, swapping to an off-road x-pipe will change the sound a little bit. A little bit.
Mid-length - box stock - when run with high-flow cats - do not throw a code with out a tune. Meaning, it is arguable that changing to mid-length would not lead to harm with the powertrain due to a modification you did to the car. Long tube, box stock, throw a code and you need to get a tune to turn the CEL off, calibrate to the right settings to compensate, and you would need a tune to get the most from the change as well. Your not going to argue your way out of that one as easily from a warranty claim perspective.
#27
Safety Car
SHORTIES are best for idle - midrange power; where most folks drive.
LTs are best for the Track (mid-upper power)
It takes 20hp for the average joe to 'feel' it. A tuner, maybe less.
Personally, I'm looking at the TSP LTs with catted hipipe; albiet shorties show me an interest in daily driving too... IDK
LTs are best for the Track (mid-upper power)
It takes 20hp for the average joe to 'feel' it. A tuner, maybe less.
Personally, I'm looking at the TSP LTs with catted hipipe; albiet shorties show me an interest in daily driving too... IDK
#28
Safety Car
Hey, as far as warrany goes...can you just load your stock tune back if you take it in? Also I paid for a warranty from a 3rd party when I purchased my car and it came with a am CAI and corsa axleback, anyways ya if I just load the stock tune wouldn't they have no idea? And its not a GM warranty..
They can still read the ECU and see that it had been tuned at some point. So putting the stock tune back in won't matter.
#29
Mid length will give you about half the power of long tubes. But the mid lengths will bolt up to the stock X pipe and since the primaries are not that long it wont have a huge effect of cylinder chamber scavenging. Additionally it will keep the O2s a little closer to the exhaust ports on the heads which will keep the fuel trims closer to stock. You also won't be pushing that much more air through the engine so you won't go much further up the MAF Frequency Range. So you don't need to adjust engine timing or fueling to compensate for either.
Long tubes moves the primary O2's further away from the exhaust ports which means you SHOULD adjust the narrowband O2 sensor mv range and reaction speed to compensate. Additionally, the extra exhaust scavenging and air flow means you SHOULD change your timing values for power and drive-ability. And lastly, you will be going further up the MAF frequency range at full throttle and will need to adjust the MAF values to keep fueling in line. You could also change the VVE in the tune but its not necessary I suppose. Only if you really want to be super OCD.
Long tubes moves the primary O2's further away from the exhaust ports which means you SHOULD adjust the narrowband O2 sensor mv range and reaction speed to compensate. Additionally, the extra exhaust scavenging and air flow means you SHOULD change your timing values for power and drive-ability. And lastly, you will be going further up the MAF frequency range at full throttle and will need to adjust the MAF values to keep fueling in line. You could also change the VVE in the tune but its not necessary I suppose. Only if you really want to be super OCD.
MAN THANK YOU! i have been scowering the forum looking for this exact bit of information you just provided. Thank you! i was wondering about header fitment to my current corsa double helixx, but after this, i am certain i am just going with a full long tube setup and not mid length to line up to my corsa. I will go with Texas speed, Kooks, or maybe american racing, but in any event will use full length. Excellent explanation and detail here!
#30
Le Mans Master
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2020 Corvette of the Year Finalist (performance mods)
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Personally, on a C7 I wouldn't bother with headers at all, too much trouble for the minimal gain. Having said that, if you're going to do headers, long tubes or nothing. The factory exhaust manifolds are basically shorty headers already.
#31
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If you are going to bother with headers anyway, do long-tubes, get a pro tune, and get something out of the effort.