lost low end torque with LT headers

01mgvert · Jun 21, 2004

I thought that someone else had posted about the loss of low end torque with LT headers when followed with an o/r x-pipe. They explained that the loss of torque was due to the loss of back pressure. Anyone remember this discussion. I seem to be having the same problem? I just had Hooker LT headers with an o/r x-pipe installed and my 0-60 mph time increased from 5.3 seconds to 5.6 seconds even though I gained 23 rwhp and 28 ft/lbs of torque. If I remember right, this person welded in some high-flow cats to successfully regain the low-end torque. Any recollections?

Dark Knight GT · Jun 21, 2004

Uhm, I lost some low end torque with my long tube headers. I guess thats normal but it should clear up in high rpms. I have hi-flow converters on my prochamber at I remember when I put them on, I got some backpressure and a little low end torque back but I don't think I'm the guy you're reffering to.

2002BLGT · Jun 21, 2004

more power=less traction , longtubes vs manifolds = more weight on front end of car = less traction again , thats probably why you are slower to 60 mph , but I bet anything you will pick up atleast 2-3 mph in the quarter

kurst · Jun 21, 2004

There have been many more then one discussion on this, and it's widely known that loss of back pressure with a free-flowing exhaust will result in loss of low end torque. Increase back pressure, lose some top end gains and get back some low end torque. Instead of talking a half step back like welding in cats, I'd just keep modding and get some better tires, and maybe change your driving style a bit.

Jackie Chan · Jun 21, 2004

um, im looking at your dyno's and i dont see where you lost any power...maybe im crazy or something

01mgvert · Jun 21, 2004

Jackie Chan said:
um, im looking at your dyno's and i dont see where you lost any power...maybe im crazy or something

What is really weird about the dynos is that they seem to compare apples and oranges. The pre-mod dyno compares STD horsepower and torque with speed (mph) while the post-mod dyno compares SAE horsepower and torque with rpms. What's up with that?

Jackie Chan · Jun 21, 2004

personally i doubt you lost anything anywhere, if you did its do to tuning issues if anything. As far as your gtec, i would trust that thing to be a stop watch.

BNH4.6 · Jun 21, 2004

I lost a buttload of tourqe below 2,500 rpms with my longtubes off road x and 12 inch borla center in/out XR-1 mufflers. I took out my borlas and welded in 3 chamber flowmasters and gained a ton of lowend. My top end is fine too! Dyno number in sig is with the current setup after or 8 or 9 pulls. Temp was 91 with 84% humidity, I can't wait to see what it feels like on a cool fall night!!!!

01mgvert · Jun 21, 2004

kurst said:
There have been many more then one discussion on this, and it's widely known that loss of back pressure with a free-flowing exhaust will result in loss of low end torque. Increase back pressure, lose some top end gains and get back some low end torque. Instead of talking a half step back like welding in cats, I'd just keep modding and get some better tires, and maybe change your driving style a bit.

What mods would you recommend? I already installed Steeda lower control arms. I'm thinking of buying some Nitto Drag Radials. Anything else?

jrc_03_gt · Jun 21, 2004

I believe you but no one else will. people like to argue. LOL!

01mgvert · Jun 21, 2004

2002BLGT said:
more power=less traction , longtubes vs manifolds = more weight on front end of car = less traction again , thats probably why you are slower to 60 mph , but I bet anything you will pick up atleast 2-3 mph in the quarter

I did have a problem hooking up with the additional 23 rwhp. Spinning the rear times is actually kind of fun, especially since my auto vert was reluctant to spin before. Anticipating the problem with traction, I had Steeda lower control arms installed at the same time as the headers. Yet, the car spins for about 10 feet and even begins to slide sideways. Again, this is a great feeling but it doesn't do much to improve dead stop acceleration. I did find an old country road with tar embedded with stones. I was able to get the car to hook up but I was disappointed with my 0-60 mph times.

Blakers01GT · Jun 21, 2004

I won't get into all the techincal crap about back pressure BLAH BLAH...

But BEFORE I got my LT's/Bassani O/R x-pipe installed, my buddy who had the same gears, bolt on's as me, but he has a o/r x-pipe, timing adjuster more then me, when we would run he would consistantly pull me by 3 car lengths from 40 - 110 mph. when I got my LT's/Bassani X-pipe, when out and ran him and I pulled him by about a car length form 40mph-110 mph(he was pissed because he thought he was still gonna pull me)......

THEN he got a c&L pipe or whatever, sold me his Timing adjuster, so he DIDn't have his Timind adjuster, I put it on, set it to 16*, pulled him by about 2.5 cars consistantly

03trubluGT · Jun 21, 2004

Again the myth continues......

I've yet to see anyone claim a loss of low end torque post their before/after dyno like I have.

I went and baseline tested my 'Stang and paid for the dyno.

I bought the parts and installed them with help.

I re-dynod the combo.

This is what I gained.

No loss of torque period! Matter of fact, it's pretty much a solid consistant gain throughout the powerband.

The HP gain starts out small and grows to about 23 net gain.

Again, you won't find anyone to post their dyno to the contrary, because they are all out quoting "experts" and not doing it themselves.

I pony'd up for the test, and you can believe me, who's spent my time and money trying to educate folks on these boards, or the people who would rather say "I heard blah blah blah"....

http://forums.stangnet.com/showthread.php?t=474507

Matt

BNH4.6 · Jun 21, 2004

I didn't hear bla bla bla I did gain 14 rwhp and 23 rwtq with my long tubes and dr. gas vs. magnaflow x with cats and the same borla catback. However, with the long tubes and off road x with the same small borla mufflers I lost low end tourqe vs. the flowmasters welded in place of the straight through mufflers. I wish I could post all 3 dynos but I don't have a scanner. All I'm saying is that with MY CAR and MY MODS I lost lowend tourqe below 2,500 rpms with a sraight through muffler vs. flowmasters. There is no doubt I gained with long tubes but with different mufflers I gained more through out the powerband vs. peak numbers. With the borlas I made 254 rwhp and 305 rwtq with no bottom end. With the flowmasters I made 262 rwhp and 302 rwtq and my rwtq never is below 270 from 2,000 rpms till near redline. I hold over 275 rwtq from 2,300 rpms until 5,500 rpms and over 300 rwtq from 4,000 rpms until 4,700 rpms. I don't guess!! I had dynos run from one of if not the best tuners for modular mustangs!!!

Monkie · Jun 21, 2004

I could be wrong but I think Y headers give you torque and Long Tube headers give you HP.

scion4LIFE · Jun 22, 2004

BNH4.6 said:
I wish I could post all 3 dynos but I don't have a scanner.

Take a pic!!

Ryan02Stang · Jun 22, 2004

Monkie said:
I could be wrong but I think Y headers give you torque and Long Tube headers give you HP.

You're WAY off!

Torque loss should be minimal. The whole powerband usually improves from longtubes.

Monkie · Jun 22, 2004

Ryan02Stang said:
You're WAY off!

Hmmmm...well I'm looking at Jegs and I see a header that in the information it says "Delivers the torque of a Tri-Y and the horsepower of a big tube header..." I guess Jegs is "WAY off! " too huh?

03trubluGT · Jun 22, 2004

BNH4.6 said:
I didn't hear bla bla bla I did gain 14 rwhp and 23 rwtq with my long tubes and dr. gas vs. magnaflow x with cats and the same borla catback. However, with the long tubes and off road x with the same small borla mufflers I lost low end tourqe vs. the flowmasters welded in place of the straight through mufflers. I wish I could post all 3 dynos but I don't have a scanner. All I'm saying is that with MY CAR and MY MODS I lost lowend tourqe below 2,500 rpms with a sraight through muffler vs. flowmasters. There is no doubt I gained with long tubes but with different mufflers I gained more through out the powerband vs. peak numbers. With the borlas I made 254 rwhp and 305 rwtq with no bottom end. With the flowmasters I made 262 rwhp and 302 rwtq and my rwtq never is below 270 from 2,000 rpms till near redline. I hold over 275 rwtq from 2,300 rpms until 5,500 rpms and over 300 rwtq from 4,000 rpms until 4,700 rpms. I don't guess!! I had dynos run from one of if not the best tuners for modular mustangs!!!

Well, simply put, LTs didn't make you LOSE anything, it sounds like the combination of midpipe/catback/mufflers were to blame.

Matt

03trubluGT · Jun 22, 2004

Monkie said:
Hmmmm...well I'm looking at Jegs and I see a header that in the information it says "Delivers the torque of a Tri-Y and the horsepower of a big tube header..." I guess Jegs is "WAY off! " too huh?

Keep in mind that's what you call "advertising".... Remember people will say what they think you want to hear to sell you something.

Matt

lost low end torque with LT headers

01mgvert

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I can't get it up......ok that didn't sound right.

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