Do headers really = dyno RWHP ????

Hello, before spending the $500-$1000 for good LT headers and labor and shipping, I wondered if anyone had recently dynoed a mild bolt on car before and after a LT header install. I have heard varying opinions on this, and talk is VERY cheap. I go by dyno results only, and dislike speculation on what parts "might" produce in rwhp as many ask before bolting on.....
Thanks for the insight.

nope heads,strokers and solid cams dont do much either!

the concept for headers is simple when you look at it froma broad point of view.... the easier let your exhaust out, the easier it is for you motor push it out. when it is easier you make more power.... anyone who says LTs arnt benificial is an idiot... they simply make it easier for exhaust gas to come up which frees up power... im sure someone will have a chart

nope heads,strokers and solid cams dont do much either!


smartass remark!! lotta air no flare.....

Everybody wants to be a smart butt. But not answer your question.

Yes, long tubes make real power on any LS1. Usually 20 rwhp or more.

I got about 25hp from my SLP LT's. The LS1's make power easily, and respond well to upgrades.

h3ll....a lid will net ya about 10hp! Inproving the exh flow is one of the best things you can do. Equal lenth headers provide equal bacpressure for each cyl and give it it's own port to flow through. Instead of it fighting w/ three other cylinders. :cool:


Like was said above, The more mods you do, the more the headers free up HP from those mods.

nope heads,strokers and solid cams dont do much either!
I use a liquid cam. :thumb:

Definetly. Especially if you're going with long tubes.

Who cares about dyno #'s? Headers will make you faster!!!

I use a liquid cam. :thumb:

Amen to that. I need to top off my fluid cam. ;)

i dont have Dyno numbers of after my headers but i did gain .5 tenths and 4mph with just an LT install

Edit: thats without a tune to , soo i dont know how much power it takes to gain that much but im impressed

Even a set of mid-length headers (like the MACs) will give a good bump in power. Long-tube headers are one of the most documented modifications going for the LSx engines and well worth the money.

FWIW my dynoed 287 and 317 before headers. After header install (and on same dyno) I put down 294 and 307. What that doesn't show is that there was a loss somewhere in the neighborhood of 10 HP and just slightly more than that in TQ under the curve. I am going to have to go and get my dyno sheets from my storage unit to get the actual numbers but that is pretty close. Also my track times went from a 13.2 at 107 to 13.4 104. This is my personal experience and I have seen other cars do better. Not quite what I've seen on the internet but better none the less.

FWIW my dynoed 287 and 317 before headers. After header install (and on same dyno) I put down 294 and 307. What that doesn't show is that there was a loss somewhere in the neighborhood of 10 HP and just slightly more than that in TQ under the curve. I am going to have to go and get my dyno sheets from my storage unit to get the actual numbers but that is pretty close. Also my track times went from a 13.2 at 107 to 13.4 104. This is my personal experience and I have seen other cars do better. Not quite what I've seen on the internet but better none the less.

maybe im reading this completely wrong but your saying you lost 1/4 mile ET & MPH with headers?? then you say it was not as good as some of the results you have seen but better none the less?? I'm confused..

FWIW my dynoed 287 and 317 before headers. After header install (and on same dyno) I put down 294 and 307. What that doesn't show is that there was a loss somewhere in the neighborhood of 10 HP and just slightly more than that in TQ under the curve. I am going to have to go and get my dyno sheets from my storage unit to get the actual numbers but that is pretty close. Also my track times went from a 13.2 at 107 to 13.4 104. This is my personal experience and I have seen other cars do better. Not quite what I've seen on the internet but better none the less.


You need a tune. If you are untuned then you will run rich and destroy your gains. This is not normal and there must be a problem. Exhaust leak, untuned, sparkplug wire disconnected, etc. Most will gain 20-30rwhp with longtubes. Whoever says they won't show any gains is smoking. In fact, longtubes are one of the better hp makers for the LS1.

1quick,
I was referring to the fact that I have seen cars get better results than mine but not by much.
black,
Other than the internet I have never seen 20 to 30 rwhp made by switching to longtubes. Maybe if they installed other equipment along with headers. Of all the LS1'1, LT1,s, L98's I have seen none of them gained that much. Hell most manufacturer's don't even claim that. I am not trying to argue or start a flame war with anyone but I have never seen numbers like I do on the internet.

black,
I don't have a tune but I don't have any of the other problems you have mentioned either. Maybe with the tune I could dyno 20 to 30 rwhp with the longtubes but the thread is only talking about installing headers.

black,
I don't have a tune but I don't have any of the other problems you have mentioned either. Maybe with the tune I could dyno 20 to 30 rwhp with the longtubes but the thread is only talking about installing headers.

ok then did you hook up your exhaust to the headers to go to the dyno?



why this thread is only talking about installing the headers :rolleyes:


see you cant be that dumb of course you need a tune you dont install a new fuel pump and bitch cause it dont work because it said no where in the instructions to put gas in the tank its common sense!:cool:

1quick,
I was referring to the fact that I have seen cars get better results than mine but not by much.
black,
Other than the internet I have never seen 20 to 30 rwhp made by switching to longtubes. Maybe if they installed other equipment along with headers. Of all the LS1'1, LT1,s, L98's I have seen none of them gained that much. Hell most manufacturer's don't even claim that. I am not trying to argue or start a flame war with anyone but I have never seen numbers like I do on the internet.

If you've never seen gains of 20-30rwhp over the internet then you have to open your eyes. They are everywhere! You'll find that the ones without good gains either are untuned or have some kind of a problem. And yes the manufacturers do make claims like I said. On TSP's site they claim at least 20rwhp and on the QTP site they claim 18 hp over other LT's. Nothing you have said makes any sense, because good gains with LT's are all over the place. LOL, not trying to be a jerk but open your eyes when you do your searches. If I had the time I could pull up a gazillion posts to show you. This is such a known and easily accessible fact, that it's not even worth debating. Good luck searching!:)

Go back and reread my posts. Only on the internet will you see gains of 20 to 30 rwhp with headers. And to go with your "I need a tune" argument: why don't you just go ahead and put on a set of heads and cam with your headers then you can claim that you got 100 rwhp when you installed your headers. So to end this beating of a dead horse I am going to change my reply: Go out and buy headers. They'll give 30 hp to the weels and your car will run like a raped ape! I've never seen it in person but there are people on the internet that have gained as much as a full second!
By the way I heard that someone is selling some oceanside property in Arizona. You should look into that.

I only have dyno #s after headers, but I went from 12.98 to 12.5 with headers and nittos. I say they added a few mph to...so 13-20 hp???

Go back and reread my posts. Only on the internet will you see gains of 20 to 30 rwhp with headers. And to go with your "I need a tune" argument: why don't you just go ahead and put on a set of heads and cam with your headers then you can claim that you got 100 rwhp when you installed your headers. So to end this beating of a dead horse I am going to change my reply: Go out and buy headers. They'll give 30 hp to the weels and your car will run like a raped ape! I've never seen it in person but there are people on the internet that have gained as much as a full second!
By the way I heard that someone is selling some oceanside property in Arizona. You should look into that.




You're a lost cause bud! It's true, whether YOU have seen it personally or not. And why wouldn't you get a tune after longtubes? I wouldn't buy LT's without plans of getting my car tuned. When you relocate the O2's you cause your car to run rich. Your car will get bad MPG and will be too rich to show the kinds of gains that everyone sees....we'll except you. When people speak of 20+rwhp gains that is OBVIOUSLY including a tune. They just assume you will be getting your car tuned, since it isn't something you do without one. Who in their right mind would put LT's on their car, to just run around untuned, rich as hell, showing next to no gains?

Guy,
You got 3 tenths from the Nitto's and maybe one tenth from the headers. What did you dyno before and after the headers?
Black,
Your right. You have been right all along. I'm sorry. lol.

Here's the problem. 90% of the information given on this board is regurgitated from what they read somewhere else. In every thread there will be maybe one or two people who actually post from personal experience. The rest are posts from people who have read "that this Guy saw this". But that Guy got his information from somewhere else on this board. So there is very little concrete evidence. There are people who are in the know and I take their advice but the rest is all BS.
The original thread is that he didn't want any of this "cheap talk" so I gave him my personal experiences with headers. And YES you can see those kind of gains if you do the headers, catback, tune, etc. But headers alone aren't gonna do it. Also explain to me why putting O2's another 12-18 inches farther down is gonna make it run rich? The only problem I have seen is false knock given off by the headers (LT's and shorties).

One last thing, did you also tune your car after putting on a catback? After a CAI?

I went from 252 cold air / catback to 272 rwhp with LT Hookers through my converter, UNLOCKED.

So over 20+ rwhp gain on an LT1 :) That was a long time ago tho ;)

My experience (because I really don't want to get involved in another flame thread) :

Pacesetter LT's, TSP ORY & Rumbler, SLP lid, K&N, smooth bellows, and a tune by Mike Norris @ Next Level Performance here in Central Florida got me an SAE corrected 346.2 rwhp and 359 rwtq.

A lot of that power was in the tune. Dyno numbers vary from day to day, car to car, dyno to dyno, etc. from all that I've read. Will headers really give you more rear wheel horse power? If your car is tuned right then yes yes yes YES! I baselined at under 300 rwhp after the header install but LS1's have a computer that will "relearn" and mine had not yet relearned after installing the headers etc. So I picked up horsepower from the tune, but also from the headers. How much from each? Who knows. Maybe Mike Norris does. Who cares? Not me, I think if you're going to do work that significantly alters the amount of air going into or out of the motor, you need to do it right, which includes having someone who knows what they're doing strap your baby to a dyno and tune her. Don't want to spend $500 on a dyno tune? Spend less on a mail-tune, or don't be surprised when your car doesn't run as well since you don't want to include a tune in the price of doing the job. For me, it was an expense just like new gaskets.

Abe

The guy who lost from the headers must have an LT1 and burned a plug wire on them, because headers = horsepower. :lol:

I gained around 20rwhp/10rwtq (low torque because they are 1-7/8" primaries) untuned with my headers and another friend of mine gained 20/30 with LG Motorsports longtubes.

They ALWAYS add alot of power, even without a tune.
It's just the nature of the beast.

Mike

This is the last time I am going to talk about this. Abe I couldn't agree with you more. However all I see on here is people quoting peak numbers. My original argument was about power under the curve (and I'm not talking about 2500 rpm either). I gained 7 to the wheels peak but my torque was moved up the powerband and the ramps on the graphs were much steeper with the headers than without. Go and check your dynographs and I'll bet some of you will see that same problem (not all.) This guy wanted to know personal experiences of what they got with headers. I gave him just that and then a few of you wanted to start a flame war. So to the guy who started this thread I apologize for being part of this trainwreck. To the rest of you :rolleyes: .

This is the last time I am going to talk about this. Abe I couldn't agree with you more. However all I see on here is people quoting peak numbers. My original argument was about power under the curve (and I'm not talking about 2500 rpm either). I gained 7 to the wheels peak but my torque was moved up the powerband and the ramps on the graphs were much steeper with the headers than without. Go and check your dynographs and I'll bet some of you will see that same problem (not all.) This guy wanted to know personal experiences of what they got with headers. I gave him just that and then a few of you wanted to start a flame war. So to the guy who started this thread I apologize for being part of this trainwreck. To the rest of you :rolleyes: .


As long as the primaries aren't overly huge and the total length of the header is kept long to increase overall torque, you will gain power both under the curve and peak power over exhaust manifolds. Obviously if you're running too big a primary and open headers or exhaust, your torque curves are going to change.

Mike

Mike

Here's the problem.

No here's the problem. You're talking about LT1s and were talking about LS1s.
You've started this huge todo because you didn't get 20 hp on your LT1 and I would bet money that any stock LS1 would get 20 or more from Long tubes with a good catback.

Here's the problem. 90% of the information given on this board is regurgitated from what they read somewhere else. In every thread there will be maybe one or two people who actually post from personal experience. The rest are posts from people who have read "that this Guy saw this". But that Guy got his information from somewhere else on this board. So there is very little concrete evidence. There are people who are in the know and I take their advice but the rest is all BS.
The original thread is that he didn't want any of this "cheap talk" so I gave him my personal experiences with headers. And YES you can see those kind of gains if you do the headers, catback, tune, etc. But headers alone aren't gonna do it. Also explain to me why putting O2's another 12-18 inches farther down is gonna make it run rich? The only problem I have seen is false knock given off by the headers (LT's and shorties).

Moving the O2's further downstream throws off the computers calibration and makes it think you are running too lean. You really aren't running too lean, but the computer thinks so, and dumps in more fuel. This is why(in laymens terms) you need to tell the computer that the A/F ratio isn't lean, so it doesn't have to dump in so much fuel. This is the prime reason you need a tune after longtubes. This is why people make nice gains with a tune after doing longtubes. And to 95firehawk: One of the best reasons for getting longtubes is for low rpm torque production. You lengthen your primaries to enhance torque production and increase the scavenging effect. The mac mid-length headers show close to the same peak hp gains as longtubes, but less power below 4,000 rpm. This is because of the longer primaries and their ability to enhance low end torque production. Your kind of gains could be seen with big 1 7/8 primaries on a STOCK car that's untuned. Otherwise 1 3/4 longtubes are without a doubt good for 20+RWHP. Why do you think they are so popular? It isn't just because they look cool. You will see bolt on cars with longtubes dyno 350rwhp, but how many with stock exhaust manifolds dyno that??? A real strong one might dyno 320-330 rwhp, if they are lucky. Hmmmmmm 20rwhp less!:rolleyes:

AL SS590 M6 ~ LS1 cars arent the only ones that respond to bolt-ons well. Its pretty much the norm to gain over 20RWHP with long tubes. He just seems to be the freak incident.

Black9TA8 ~ 99% of the guys on the LT1 forum are installing long tubes WITHOUT a tune and still seeing 20+RWHP gains, same conditions for heat humidity etc. You DO NOT need a tune for headers. And my fuel mileage went up for sure around 2 mpg city driving after a long tube install without a tune. Bottom line is your wrong. Anyone that has installed long tubes and lost power has something wrong with their car. It does not make it run so rich that they loose power.

The real reason there is power behind a tune, especially with headers:

LT1 & LS1 cars run rich from the factory. In power enrichment mode (Close to full throttle, to WOT), the computer takes a reading from the TPS and injects a significantly lengthens the injector pulse widths. They can commonly run as rich as 10.5 to 1 at WOT. Ideal would be in the 13ish area. When you get a tune for an LT1/LS1 car that is stock/minor bolt ons, nearly all the increased power comes from leaning the mixture out. The more modified the vehicle is, the bigger the gains it will show. Therefore, a mail order tune before headers may give you 5-10 RWHP, a mail order tune after headers, cai, catback, etc could show potentially more.

If you are debating on whether to get headers or not, get them. And dont listen to Black9TA8 about needing a tune.Almost every person who gained 20RWHP DEFINATLY didnt have a tune. Every other person I have ever seen both in person, on the board, or at the local speed shops, have all shown very decent gains with headers and no tunes, and slightly better with a tune. You will not loose performance with long tubes, and as long as your car is running well ( New plugs wires filters etc) you absolutly will see nice gains. At least 15 RWHP with long tubes. Actually I would be sort of dissapointing if I only gained 15. Wait until you are done with all your bolt ons to get a tune. Its absolutly retarded to spend 100$ for a mail order tune every time you buy a new bolt on for your car. What are you gaining? Id like to see before and after dyno results with a new part with a tune, after the computer has been given time to "learn" and adjust the mixture on its own.

As for 95firehawk:

You either burned a plug wire, or are getting flase knock. Its common to loose some low end torque, say 10 lbs, but only under 2500RPM's. There is something wrong with your car if your not seeing gains pretty much from 2500RPM up in both torque and horsepower. O wait, maybe you need a tune to make any gain with them headers ...

As far as that goes, heres something to think about ... The oxygen sensors measure sense oxygen, moving them 12 inches isnt going to change the exhaust content when its in a sealed header:rolleyes: And before you even say it, the resistance in the extra wiring of the O2 connectors would, if any difference, cause it to lean out even more. And if our cars (LT1 and LS1) run lean from the factory at WOT, then once you are free-er flowing with headers, lid, etc, wouldnt it slowly be leaning itself out as its getting more air in, but, according to you, not accomodating for fuel? That would put us closer to the ideal AF mixture. Making even more power. Bottom line, you DONT need a tune. It helps, but your car is NOT going to get bad mileage, horrible driveabilty, or loose horsepower off of headers or other bolt ons without a tune.

Trust me on the tune thing. Have you aver datalogged a car after longtubes? I'm not saying some cars don't see gains with longtubes untuned. And yes you can run your car untuned with longtubes. Your car runs rich from the factory, and will even run richer with the relocated O2's. Datalog pre and post LT's and see what happens. You get your car tuned and re-calibrate the computer for the new O2 location, and you will see good gains. How come you guys can't understand this? You can also put a cam in your car and run on the stock tune, but you will run rich down low and lean up top no matter how long you give your car to compensate. Your air/fuel ratio must be dialed in if you want to run right. And HardcoreRM 125, it isn't that your computer can't compensate for the header, it's that it doesn't know how, because it's basing it's adjustments for a car with the stock O2 location. Of course the computers can compensate somewhat for mods, but it needs known parameters. Moving your O2's downstream throws this right out the window. It's the same reason you can't just throw bigger fuel injectors in your car and expect the computer to compensate. Your car will run like crap. It will be trying to adjust and make it's calculations based on the stock injector calculations, which doesn't work.

How can it throw it off? Your exhaust mixture is the same 12 inches down as it is in the stock location. It also is still reading the exhaust from all 4 cylinders per side, just like it does the way their plumbed into the manifolds. Since its a sealed system, I dont see how the exhaust mixture can change that drastically, especially since its only 12 inches. I mean, i understand what your saying, but its not like their being moved several feet, its only a matter of a few inches?

Is it because the sensor remains colder in a header than it does in a manifold that gets heat soaked really fast? Where as the headers you could almost toch them where the O2 comes in? I really dont see the headers cooling and affecting the exhaust mixture that much? But I'm not going to claim to know everything ... I would like to know how it affects it though, further away or not, what is the difference that makes it run richer?

I have a true Bolt-on queen. well for now anyway.

Lid, filter and a Borla Exh and catted Y w/ LT's.... That's basically it... Dyno'd 336/346 after an LS1 edit.

I have a true Bolt-on queen. well for now anyway.

Lid, filter and a Borla Exh and catted Y w/ LT's.... That's basically it... Dyno'd 336/346 after an LS1 edit.


Not trying to be a jerk, but those #'s are kind of on the low average side. I wouldn't call it a bolt-on queen.

Not trying to be a jerk, but those #'s are kind of on the low average side. I wouldn't call it a bolt-on queen.

Agreed. After my lid and cutout, i was putting down 330 to the wheels. So 336 after lts, catback, and lid, those arent the best numbers. Definetly not bolt on queen worthy.

He's running through cats though. His car is a 2000, so it wouldn't have the LS6 intake manifold right? I dont really follow the stock minor factory changes through the years. Their not bad numbers either for cats, and only a intake/exhaust.

I would say those numbers are pretty close to what it should be at. Say 300-305 stock RWHP, + about 30 for an exhaust and intake.

Hello, before spending the $500-$1000 for good LT headers and labor and shipping, I wondered if anyone had recently dynoed a mild bolt on car before and after a LT header install. I have heard varying opinions on this, and talk is VERY cheap. I go by dyno results only, and dislike speculation on what parts "might" produce in rwhp as many ask before bolting on.....
Thanks for the insight.


Yes!

He's running through cats though. His car is a 2000, so it wouldn't have the LS6 intake manifold right? I dont really follow the stock minor factory changes through the years. Their not bad numbers either for cats, and only a intake/exhaust.

I would say those numbers are pretty close to what it should be at. Say 300-305 stock RWHP, + about 30 for an exhaust and intake.


Mine is a 2000.....and i have cats....and stock manifolds.

Those #'s are just from dyno queen status IMHO. Calling your car a dynoqueen suggests that you are putting down higher than average #'s for the mods you have. 336rwhp is not higher than average for a longtube car by any means. Strong cars like Aklaims can put down 330 with a lid and catback. I definately wouldn't consider 336rwhp for any LS1 with longtubes a "dynoqueen." I've seen strong cars dyno 350rwhp with just longtubes....now that's what I call a dynoqueen.

He's running through cats though. His car is a 2000, so it wouldn't have the LS6 intake manifold right? I dont really follow the stock minor factory changes through the years. Their not bad numbers either for cats, and only a intake/exhaust.

I would say those numbers are pretty close to what it should be at. Say 300-305 stock RWHP, + about 30 for an exhaust and intake. i think it was the 01-02s that came with the LS6 intake,

but i was thinking the other day that the older cars had the LS1 intake and were actually rated lower, as to where the newer ones had some differences adn the LS6 intake, o intake and headers with exhaust may make slightly more power

but im not sure, i dont know much about my LS1s

so....does anyone know the price of tea in china?

cause i've heard that it's a steal...

:rolleyes:

when is this thing gonna get locked....

You are correct, all 01-02s came with the LS6 intake. And all of mine were .15 faster in the 1/4 than non ls6 intake ls1s ive driven.

How can it throw it off?
Is it because the sensor remains colder in a header than it does in a manifold that gets heat soaked really fast?

Bingo, O2 sensors work off of heat. As a matter of fact that is how you test a sensor to see if it works, heat it with a torch with a Multimeter hooked up. And they are closer to 2 feet farther downstream so the temps could be quite different.

Oic, Interesting stuff ...

I never really gave it much thought. I see how that could throw the readings off though. I'll have to borrow my uncles snap on scanner and make a few WOT runs to see what mV readings I get out of my O2's with my headers on. I remember a while back before my headers, at WOT, they would stay in the 700-800mV range. That seemed right to me since they run rich from the facotry under WOT, and they should fluctuate from 100-900mV, the higher the voltage being richer ...

I'll keep this in my email and post a reply whenever I can borrow his scanner and take some readings now with the headers, and mileage, to see how far they vary from the baselines ... This was on a 60 degree day with the car hot and idling for several minutes, so it should be easy to duplicate. I know the humidity will be off, but I would think it should be close enough to show a difference:confused: I'll reply whenever I get a chance too though so it ma be a while cause its not too often I can get my hands on a several thousand dollar tool.:cry: