Paxton, headers and Heat:

[sleeper]

Silver, doesn't make since like mike said that those with headers installed would be making upwards of 760-770 hp. So where are these guys? I don't think headers help on this application.

 

[Silverback]

Okay.

Headers are worthless pieces of shit. End of discussion so we can all move on.

 

[JTS VENOM PERFORMANCE]

header discussions makes my balls itch!lololololol

 

[Nowwhat]

header discussions makes my balls itch!lololololol

you are just upset that you bought a Volant for the QC....

 

[Silverback]

header discussions makes my balls itch!lololololol

So does everything else Stinker. :rock:

 

[Ram From Hell]

As I suggested previously, the stock manifolds must become an ever greater limiting factor in power production as you increase HP. If you're NA, you're nuts if you don't opt for headers for the yield in HP/$, right? But up to a point with FI, it sounds like headers may not be worth the expense. At what point though does it become enough of an advantage with FI to be done, is the question we ought to be asking. If you insulate what needs to be insulated such that heat soak isn't ever an issue, I cannot see where headers could EVER reduce you're output. So it is simply a matter of how much they increase it by, versus the cost & hassle.

Does that sound about right?

 

[Silverback]

As I suggested previously, the stock manifolds must become an ever greater limiting factor in power production as you increase HP. If you're NA, you're nuts if you don't opt for headers for the yield in HP/$, right? But up to a point with FI, it sounds like headers may not be worth the expense. At what point though does it become enough of an advantage with FI to be done, is the question we ought to be asking. If you insulate what needs to be insulated such that heat soak isn't ever an issue, I cannot see where headers could EVER reduce you're output. So it is simply a matter of how much they increase it by, versus the cost & hassle.

Does that sound about right?

Nope. Headers are a piece of shit. Don't ever use headers.

 

[Nowwhat]

As I suggested previously, the stock manifolds must become an ever greater limiting factor in power production as you increase HP. If you're NA, you're nuts if you don't opt for headers for the yield in HP/$, right? But up to a point with FI, it sounds like headers may not be worth the expense. At what point though does it become enough of an advantage with FI to be done, is the question we ought to be asking. If you insulate what needs to be insulated such that heat soak isn't ever an issue, I cannot see where headers could EVER reduce you're output. So it is simply a matter of how much they increase it by, versus the cost & hassle.

Does that sound about right?

yes that sounds exactly right....

at some point the manifolds will hold you back...but that number is north of 700....and to go north of 700 you aren't that worried about $2000 anymore as you have spent a shiteload....

to go significantly north of 700 and run a paxton...you need forged internals, headwork or styrkers..etc..etc and at that level you are no longer worried about the headers leaning you out as you no longer have a stock fuel system either....

for my build....no headers....if I want more hp I just up the shot.... ...plus...there are 5 or so trucks coming up (yours included) that are going to beat my 1/4 mile...so I want to keep the World's fastest SRT with stock manifolds title....

 

[Nowwhat]

I like post toooo

"Mike I got your back on this one.

This is how it was explained to me by Doug Levin. A stock engine's exhaust is about 80%-85% efficient. When you do you delete cats, add a cat-back and headers the exhaust efficiency goes to about 90% on an NA engine. Now on an FI engine just by deleteing cats and adding a cat-back the exhaust efficiency is approximately 120% way past it normal effiency that is why the headers do not add much rwhp on the dyno because the engine beyond its max, but they are other benefits to having headers (bling and sound).

Doug even showed me a Viper GTS Coupe he just finished doing this car had a tune, paxton with custom heat exchanger with stock exhaust manifold, stock front cats with rear deletes and B&B cat back. Dyno 636 rwhp 627 rwtp. I asked him why didn't the owner do long tubes he told me it was worth the rwhp gain to do the header $2000 for 3 rwhp. Oh and this car was a sleeper (super quite) by Viper standards."

 

[Kevan]

A stock engine's exhaust is about 80%-85% efficient.

That's pretty damn impressive.
I wonder what it is on a hybrid, or a '73 Chevelle (straight 6).

 

[nycstev]

I like post toooo

"Mike I got your back on this one.

This is how it was explained to me by Doug Levin. A stock engine's exhaust is about 80%-85% efficient. When you do you delete cats, add a cat-back and headers the exhaust efficiency goes to about 90% on an NA engine. Now on an FI engine just by deleteing cats and adding a cat-back the exhaust efficiency is approximately 120% way past it normal effiency that is why the headers do not add much rwhp on the dyno because the engine beyond its max, but they are other benefits to having headers (bling and sound).

Doug even showed me a Viper GTS Coupe he just finished doing this car had a tune, paxton with custom heat exchanger with stock exhaust manifold, stock front cats with rear deletes and B&B cat back. Dyno 636 rwhp 627 rwtp. I asked him why didn't the owner do long tubes he told me it was worth the rwhp gain to do the header $2000 for 3 rwhp. Oh and this car was a sleeper (super quite) by Viper standards."

How about FI with complete stock exhaust.. or the very least catback?

 

[Rice Eater]

damn ya'll tooke me a half hour to catch up on this thread since lunch time....plus I'm drunk as hell! My .02.....headers look damn good when you pop the hood for the bling....which i had gotten the bellangers....they look the best! I think I'd trade my mopar LT's for a VEC3 at this point! Think I'd get more out of a NOS tune than the headers!

 

[Nowwhat]

I think I'd trade my mopar LT's for a VEC3 at this point! Think I'd get more out of a NOS tune than the headers!

:rock: :rock: :rock: :rock: :rock:

 

[DC Performance]

Sounds like I need to chime in here.

I can only give you my results from building supercharged engines for Vipers over the past 10 years, your results may differ.

On a stock supercharged viper engine, we see no gains over running headers with high flow cats or stock manifolds with high flow cats. At that level the stock manifolds flow just fine and the engine does not benefit from the scavage effect because the blower tends to push the air. I have tested many stock blown engines with and without headers and the only benefit is
some midrange torque. I just do not think this is worth 2-3k expense. If you want every last bit of hp then use them. Non-supercharged engines show a noticeable gain.

If you do use headers, you should put heat covers on them. They have more area than the stock manifolds and come closer to the airbox and blower, causing more heat soak.

On highly modified engines with aftermarket heads, bigger ports, cam changes and high boost, headers are an absolute must. You are creating a road block right at the bigger exhaust port. All of our engines with modified heads use headers. In Mike Brady's case, his heads are modified extensively for durability but have absolutely no porting and being that his truck has a high flow exhaust with no cats (race use only) the headers make no sense.

I hope this helps.

 

[moparracing]

Sounds like I need to chime in here.

I can only give you my results from building supercharged engines for Vipers over the past 10 years, your results may differ.

On a stock supercharged viper engine, we see no gains over running headers with high flow cats or stock manifolds with high flow cats. At that level the stock manifolds flow just fine and the engine does not benefit from the scavage effect because the blower tends to push the air. I have tested many stock blown engines with and without headers and the only benefit is
some midrange torque. I just do not think this is worth 2-3k expense. If you want every last bit of hp then use them. Non-supercharged engines show a noticeable gain.

If you do use headers, you should put heat covers on them. They have more area than the stock manifolds and come closer to the airbox and blower, causing more heat soak.

On highly modified engines with aftermarket heads, bigger ports, cam changes and high boost, headers are an absolute must. You are creating a road block right at the bigger exhaust port. All of our engines with modified heads use headers. In Mike Brady's case, his heads are modified extensively for durability but have absolutely no porting and being that his truck has a high flow exhaust with no cats (race use only) the headers make no sense.

I hope this helps.

for those of us that choose headers, what's your opinion on coating them (hpc or jet-hot or not at all) ??
thanks.

 

[Prof]

Looks like the consensus is that headers do not hurt! Boomer and Silverback are in favor, Mike is against (but has the very fastest truck) and DC Performance says yes maybe but not normally worth the investment.

I think that most of us build over a year or so...headers came early on for me because it made sense when I did a cat delete and was normally aspirated. I planned to put the Roe on but it was not ready, and I still needed to add the VEC III, water/meth and a couple of other things.

I would bet that headers will continue to be a part of most of our builds and that most will enjoy them for the performance aspects prior to forced injection and for looks, sound and ego after FI.

Lots of learning on this thread...we need more like this one!

 

[JMB Justin]

Sounds like I need to chime in here.

I can only give you my results from building supercharged engines for Vipers over the past 10 years, your results may differ.

On a stock supercharged viper engine, we see no gains over running headers with high flow cats or stock manifolds with high flow cats. At that level the stock manifolds flow just fine and the engine does not benefit from the scavage effect because the blower tends to push the air. I have tested many stock blown engines with and without headers and the only benefit is
some midrange torque. I just do not think this is worth 2-3k expense. If you want every last bit of hp then use them. Non-supercharged engines show a noticeable gain.

If you do use headers, you should put heat covers on them. They have more area than the stock manifolds and come closer to the airbox and blower, causing more heat soak.

On highly modified engines with aftermarket heads, bigger ports, cam changes and high boost, headers are an absolute must. You are creating a road block right at the bigger exhaust port. All of our engines with modified heads use headers. In Mike Brady's case, his heads are modified extensively for durability but have absolutely no porting and being that his truck has a high flow exhaust with no cats (race use only) the headers make no sense.

I hope this helps.

I definitely agree on this......for a viper. A viper has a much better design of a tubular header from the factory (98 up cars at least) than our trucks. Even the early cars had a decent cast 5 into 1 header, and those owners that switch to the later tubular manifold usually only pick up a couple HP. I have personally seen the exact same things that DC is saying, usually under 5HP for Headers on a 600HP supercharged viper. That being said, from what I have seen the trucks are picking up good gains with good headers. My personal puny 475 HP NA combo picked up about 20HP and torque with only belanger longtubes, ZERO other changes, and even bigger gains under the curve. If they are a restriction at 455HP, they are definitely a restriction at 700HP. No engine benefits from excessive backpressure, not a N/A, not a turbo, and not a supercharged. I would bet that even the short bassanis would net a minimum of 20-30HP if tuned to the same A/F ratio and boost (if it changed) as his current setup. Mike, I have an extra set here and would be more than happy to let you try them
Justin

 

[drcraig]

I definitely agree on this......for a viper. A viper has a much better design of a tubular header from the factory (98 up cars at least) than our trucks. Even the early cars had a decent cast 5 into 1 header, and those owners that switch to the later tubular manifold usually only pick up a couple HP. I have personally seen the exact same things that DC is saying, usually under 5HP for Headers on a 600HP supercharged viper. That being said, from what I have seen the trucks are picking up good gains with good headers. My personal puny 475 HP NA combo picked up about 20HP and torque with only belanger longtubes, ZERO other changes, and even bigger gains under the curve. If they are a restriction at 455HP, they are definitely a restriction at 700HP. No engine benefits from excessive backpressure, not a N/A, not a turbo, and not a supercharged. I would bet that even the short bassanis would net a minimum of 20-30HP if tuned to the same A/F ratio and boost (if it changed) as his current setup. Mike, I have an extra set here and would be more than happy to let you try them
Justin

I can see the new Mike Brady post now: Guess Nowwhats HP with Justins's borrowed headers

 

[Manic]

I can see the new Mike Brady post now: Guess Nowwhats HP with Justins's borrowed headers

And win nothing...

 

[Ram From Hell]

Now on an FI engine just by deleteing cats and adding a cat-back the exhaust efficiency is approximately 120% way past it normal effiency that is why the headers do not add much rwhp on the dyno because the engine beyond its max

I don't get where the quote about "120%" exhaust efficiency comes from (technically speaking). Yeah, I realize this was supposedly quoted from someone at DLM.

This percentage can't possibly take into account that there is more air being stuffed into the engine, presuming that 100% efficiency means it gets complete evacuation of the spent air/fuel charge. Where the heck is this guy coming up with another 20%??? And by this guy's calculations, would the efficiency with the headers end up at 130%?:dontknow:

yes that sounds exactly right....

at some point the manifolds will hold you back...but that number is north of 700....and to go north of 700 you aren't that worried about $2000 anymore as you have spent a shiteload....

Yeah, but don't advertise that fact to my wife.

to go significantly north of 700 and run a paxton...you need forged internals, headwork or styrkers..etc..etc and at that level you are no longer worried about the headers leaning you out as you no longer have a stock fuel system either....

for my build....no headers....if I want more hp I just up the shot.... ...plus...there are 5 or so trucks coming up (yours included) that are going to beat my 1/4 mile...so I want to keep the World's fastest SRT with stock manifolds title....

Well, a title is good to have. I'll settle for being labeled infamous or notorious.