proven hp from lt headers
proof is in the time slips. they do add horsepower. i cant say how much, it varies on application, id say anywhere from 15-25.
longtubes do nothing but help you. The only downside is if your running say an SLP loudmouth exhaust with no cats. I felt a loss in torque with this setup on my old M6 z28. Add a borla muffer or whatever you choose to add backpressure and your safe. Id say this is the only instance where this would happen is with the loudmouth.
even with the loss of torque, peak horsepower increased still
longtubes do nothing but help you. The only downside is if your running say an SLP loudmouth exhaust with no cats. I felt a loss in torque with this setup on my old M6 z28. Add a borla muffer or whatever you choose to add backpressure and your safe. Id say this is the only instance where this would happen is with the loudmouth.
even with the loss of torque, peak horsepower increased still
backpressure is your enemy any way you look at it. why does it matter how much hp they add? you shouldnt be bragging about a bolt-on lt1 anyways. the point is that you need them.
TECH Regular
Joined: Apr 2007
Posts: 420
Likes: 0
From: Kempner, TX
I agree!
It's just one of those things that simply won't die. Although it's discredited across the board, from the major exhaust manufacturer's to the most highly acclaimed engine builders and about everyone in between, some still claim an engines need exhaust back-pressure.
Every Tech article interview I've read where the topic of exhaust is being discussed, the engineers being interviewed say essentially the same thing - For best power you'd want as little back-pressure as possible.
Jake
It's just one of those things that simply won't die. Although it's discredited across the board, from the major exhaust manufacturer's to the most highly acclaimed engine builders and about everyone in between, some still claim an engines need exhaust back-pressure.
Every Tech article interview I've read where the topic of exhaust is being discussed, the engineers being interviewed say essentially the same thing - For best power you'd want as little back-pressure as possible.
Jake
Dude if you dont think that headers add hp on a LT1 you are smoking that good cali weed out there. they are about 20hp gain, more if you add a tune afterwards as they often set off SES lights, etc.
Trending Topics
If that's the case, I ran 12.67 @ 110mph with LPE heads/cam, Edelbrock shorties (which probably didn't flow even as good as the stock manifolds), stock y-pipe with cats in place, 4.10 gears and BFG DR's on 16" steel wheels. I did Hooker LT's with an offroad Y-pipe and did a 12.28 @ 114mph first time out. Can't credit that all to the headers, but as already stated, backpressure is your enemy.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
How's this: With CAI, gutted cat, flowmaster muffler, car went 13.632@102.32. With ASM headers, Random Tech Cat, Random Tech Cat-Back and 160* thermostat, car went 13.009@106.98 in very similar weather.
I think am going to be re dynoing on friday, and I'll post back in this thread if I do. I made 275 hp /312 tq the first time (with a K&N CAI as my only mod). We'll see how much more (if any lol) it makes. I definitely felt a difference.
TECH Resident
Joined: Dec 2005
Posts: 856
Likes: 0
From: In a house
TECH Fanatic
Joined: Nov 2008
Posts: 1,776
Likes: 1
From: South Dakota
you for real or is that sarcasm? 
The BBK shorty header for my car is much better than the stockers (IMO) but not as good as long tubes. I'm probably giving up 10 or 15 hp over a long tube but for me the extra few ponies isn't worth the hassel on a lowered car. You'll find that changing plugs and other maintenance is much easier with headers or even shorty's and its worth changing for that reason alone.
Rockstar
iTrader: (15)
Joined: Feb 2009
Posts: 1,582
Likes: 0
From: I'm on a boat! in Shreveport, La
You ever heard about these "cam" things that are supposedly the hot new thing?
Stay away from them, they'll blow your engine faster than the NAWWWSSSS!!!!
When i put longtubes on i could feel a nice SOTP difference. Now that being said i also did feel a small loss on the bottom end. the top end was much better went from 101-103...car got quieter inside once the headers were on..
At this point Lt1s have been out for 18yrs every bolt available has been done and headers seem to be on the first to do mod list..
Definately do headers
Mac Mids
Pacesetters
Jett hott
Lpp
KOOKs
MORE FACTS:
GMHIGH-TECH jan,2003 did a test on a '94z28 ATCO,NJ
BASELINE-----13.92@ 99.25 avg.
et streets and skinnies-----13.76@98.31
vig converter,rebuild tranny----13.60@97.40
Hooker shorties coated,corsa cat bac,msd wires and new plugs
13.44@99.19
Initial dyno session:
248.4HP 5600rpm
278.2TQ 4000rpm
after minor mods + vig converter
265.2HP 5600rpm
289.4HP 3600rpm
At this point Lt1s have been out for 18yrs every bolt available has been done and headers seem to be on the first to do mod list..
Definately do headers
Mac Mids
Pacesetters
Jett hott
Lpp
KOOKs
MORE FACTS:
GMHIGH-TECH jan,2003 did a test on a '94z28 ATCO,NJ
BASELINE-----13.92@ 99.25 avg.
et streets and skinnies-----13.76@98.31
vig converter,rebuild tranny----13.60@97.40
Hooker shorties coated,corsa cat bac,msd wires and new plugs
13.44@99.19
Initial dyno session:
248.4HP 5600rpm
278.2TQ 4000rpm
after minor mods + vig converter
265.2HP 5600rpm
289.4HP 3600rpm
Well, I have dyno numbers. Both times done on the same dyno, just different days.
1st dyno: Only mods were a K&N cai, no cat, and an open cutout. 275 hp / 313tq
2nd dyno: Same as above except LPP longtubes/ORY. 294 hp / 327 tq -- Not tuned
First run conditions: 62*, 37% humidity, 28.42 in-Hg.
Second run conditions: 66*, 67% humidity, 28.99 in-Hg.
1st dyno: Only mods were a K&N cai, no cat, and an open cutout. 275 hp / 313tq
2nd dyno: Same as above except LPP longtubes/ORY. 294 hp / 327 tq -- Not tuned
First run conditions: 62*, 37% humidity, 28.42 in-Hg.
Second run conditions: 66*, 67% humidity, 28.99 in-Hg.
Last edited by Slow94Formula; Sep 17, 2010 at 10:38 PM.
1) Moroso CAI, & magnaflow stock replacement muffler -- 282 hp / 323 tq
2) Moroso CAI, Trickflow elbow, Pacesetter LT's, ORY, Magnaflow catback w/ open cutout -- 296 hp / 331 tq (also untuned)
TECH Fanatic
Joined: Jun 2007
Posts: 1,255
Likes: 11
From: centerville, ohio
I also have dyno numbers from adding shorties with the x pipe, picked up 17 rwhp and 16 lbft tq. Here are 4 dyno ran results in a row for header swaps.
1. 96lt1m6 gm high tech post
Hooker shortie with a catback 17 rwhp - 11 lb. tq.
2. Lt1-xjs post
Homemade shortie with x pipe 17 rwhp -16 lb. tq
3. slow94 formula post
Lpp long tube with ory 19 rwhp - 14 lb. tq
4. Shaefz28 post
Trickflow elbow, Pacesetter lt, ory, cat back with cut out 14 rwhp -8 lb. tq.
appears none were tuned before the runs.
1. 96lt1m6 gm high tech post
Hooker shortie with a catback 17 rwhp - 11 lb. tq.
2. Lt1-xjs post
Homemade shortie with x pipe 17 rwhp -16 lb. tq
3. slow94 formula post
Lpp long tube with ory 19 rwhp - 14 lb. tq
4. Shaefz28 post
Trickflow elbow, Pacesetter lt, ory, cat back with cut out 14 rwhp -8 lb. tq.
appears none were tuned before the runs.
Now buy some headers! Lol