headers loose alot of torque?

p01rogue

New Member
Jan 2, 2005
3
0
0
have a basically stock 93 gt with offroad-hpipe and 2 chamber flows.
Will I loose alot of torque by switching out stock headers too mac 1 5/8 or should i leave it alone?
 
  • Sponsors (?)


Every motor is different but take the dyno numbers and you be the judge.

From a basically stock 5.0:

Stock: 217 hp @ 5000 rpm, 273 ft-lbs @ 3600 rpm
MAC 1 5/8" shorties: 232 hp @ 5000 rpm, 284 ft-lbs @ 3700 rpm

Little bigger engine: (couldn't find torque numbers... sorry)

Unequal Shorty: 335 hp @ 5400 rpm
Equal Shorty: 333 hp @ 5600 rpm
Long Tube: 344 hp @ 5400 rpm
 
No dyno numbers, but my wifes 5.0 is bone stock under the hood, and we installed MAC 1 5/8" shorties and a Flowpath 2.5" catback. No loss in low end, and significantly more pull over 2500. She even has the lethargic 2.73 rear, and it still goes off the line hard. Still running the stock midpipe though- as soon as my pipe guy has time to install the Prochamber that's been sitting in the corner for two weeks we'll see if it loses anything.
 
You'll be fine with mac shorties look at my sig, the dyno runs were made without the chip (I don't know if thats in there) or the home ported and polished lower. so 215 and 279 to the rear tires, or roughly 15% gain from exhaust and cam... 279 x 1.15 = 320 tq... doesn't look like a loss to me.
 
Go with the headers. I couldn't believe it when I took my stock headers off and saw what a convoluted, constipated section of intestine it looked like. What a bastard compromise THAT was to make it fit in multiple vehicles. :puke:

Gotta replace or port that stock lower intake to remove the choke point eventually, the headers are definitely a prerequisite in letting the motor breathe.
 
cjman15 said:
Nah, keep them on now... I'm sure you will plan on adding more mods later to build power... you will really appreciate it later on down the road, give yourself time to grow :nice:

"What's strong enough for a man, but built for a woman?
-- The back of my hand."

"Studiotraffic.com -- Start making money today! Free to sign-up!"





I hope I'm not the only person on this board offended by this, but are you not only spamming with every post but also advocating abuse of women?!? Tell me if I'm off base, because if not you are the most lowlife piece of **** I've come across in 18 months of using this website. :nonono:
 
stangbear427 said:
No dyno numbers, but my wifes 5.0 is bone stock under the hood, and we installed MAC 1 5/8" shorties and a Flowpath 2.5" catback. No loss in low end, and significantly more pull over 2500. She even has the lethargic 2.73 rear, and it still goes off the line hard. Still running the stock midpipe though- as soon as my pipe guy has time to install the Prochamber that's been sitting in the corner for two weeks we'll see if it loses anything.
Prochamber is in. Sounds insane, feels pretty much the same on the low end, but now it keeps pulling hard right to 6,000- it used to fall on it's face after 4,000. I haven't even pulled out the air silencer yet, maybe later...
 
Despite their appearance, the stock HO shorties don't hinder peak power until you get up into the 280-300 HP range. Most of the gains people refer to come from replacing the stock system downstream of the headers (especially stock cats/h-pipe, stock mufflers) with something that flows better.

My mild set up lost 3HP on the dyno when I swapped the HO headers for a set of 1 5/8th" FRPP shorties.

Long tubes probably won't add much peak power (again - for stock to mild combos) but they have the potential to add gobbs of low end torque.

So, if you're gonna go to the trouble of adding headers - long tubes are the way to go. And unless you're well up over 400+ HP, 1.5" primary won't hurt peak power, but will make even more low end/midrange power/torque than a 1 5/8" primary. People oversize headers regularly. Bigger is better mentality usually is exactly wrong when it comes to exhaust system tuning....
 
Ok, but wouldn't ceramic coated shorties lower underhood heat better than the OEM's? The tubing looks as if it flows better the stock. I would love to see a few dyno sheets to confirm/deny the loss in power on a stock 5.0L. Interesting info on their HP efficency though. I don't see anything wrong with adding shorties to compliment other exhaust products to allow your 300+ HP Pony to exhale properly. You won't have clearance issues or require a new starter as with the LT's. Adding a set of unequal shorties is not a high RPM job.
 
Ceramic coating on ANY header will reduce radiant heat transfer. The point is, you for mild builds (less than 300HP -- WHERE THE POSTER IS), the bigger shorties won't help at all. Long tubes WILL help the bottom end.

I believe I have both copies of my dyno runs if you really don't believe what I'm telling you happened on my car. Search the threads - you'll find many other cases of folks who didn't pick up anything on mild builds by replacing the HO headers with bigger shorties. Can't imagine why I'd mis-lead about spending all that money to brag about a loss in power. (grin)

Ambient temp. was about 45F on both runs; same dyno, same operator, different strap down session. The only changes where addition of FRPP shorties (ceramic coated), and I took my usual dino oil out and put in 5qts. of Amsoil synthetic. At peak we dropped from 225 rwHP to 222HP. There was no gain at any point in the pulls (from about 1800-5500), and the loss was greatest at peak. WHen you consider the error/variance of a normal dyno, what you can conclude is that the bigger shorties made no difference at all. As stated before, for stock/mild combos, DESPITE their appearance, the stock headers are not flow limiting.