proven hp from lt headers
#2
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
#4
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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
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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.
#8
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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.
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#13
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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.
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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!!!!
#15
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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
#17
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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; 09-17-2010 at 10:38 PM.
#18
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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)
#19
TECH Fanatic
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.