Greetings sagacious ones,this has bothered me for a while(I’m a firm believer of bang for the buck).I used to argue with some guys over just how effective extensive exhaust mods were vs a good free flowing streamlined stock system.
Basically what I’m referring to are basically stock or mildly modified engines,I’m referring to engines that usually wont see over 5000 RPMs and gearing usually no lower then say 3.92.Money well spent or not-anything better for the amount of investment? I certainly am aware of the disavantages of headers and attendent plumbing.Would please like some opinions on this issue-Kevin
First, to answer your topic question, PT Barnum was most certainly right…For the money, headers provide the least amount of performance gain…On a V8 that came with a single exhaust, the simple addition of dual exhausts provide almost as much gain as headers and dual exhausts for far less expense and trouble.
To be “street legal”, meaningful engine reworking is a thing of the past if emissions testing is part of the picture…So tuners spend their money on headers and cold-air intakes and pretend they created a 1969 Boss 302 Mustang…We all must have dreams…
Depending on year of vehicle.
Newer vehicles include about the maximum intake and exhaust flow due to the manufacturers wanting to wring max mpg and power, for both consumer demand and goverment demand.
But you’d have to pony up some bucks to prove or dis-prove anything.
What kind of improvement do you seek?
Horsepower gain? Possibly. Aftermarket exhausts often are more free flowing than factory mostly because the factory exhaust has to meet strict noise standards.
Gas mileage gains? Most likely not. When you cruise at good gas mileage speeds, the engine rpm is so low and the throttle is so closed that the factory’s exhaust restriction not much of a factor.
Thanks,this is what I wanted to verify.I remember watching a “hot rod” style TV show,the guys ripped all the old stopped up junk off an old V-6 Camaro and put a new header exhaust system(may have even put on new tune up parts)rather then starting from the tailpipe forward-they went from the exhaust ports back-pretty expensive,they got a fair amont of gain nothing outstandingly dramatic.In a nutsheel-they replaced so many componets,it was impossible to do a “bang for the buck” cost vs benefit analysis-Kevin
Not necessarily. On the 87-ish to 1995 Mustangs, gains of around 20 HP can be had with simply replacing the factory exhaust with a complete aftermarket system (headers,catted X-pipe, and single chamber mufflers). It’ll still be street legal A full bolt-on 4.6L Mustang (CAI,larger throttle body,plenum, headers, exhaust, and a tune) will produce around 30 more HP over stock. Again it’ll still be street legal.
P.T. Barnum was a genius. that aside,
it depends on: car, year, driving style, and if you even want performance.
headers are used to get the exhaust out as efficiently as possible, and not allow the gases to cool. hot air moves better, remember?
header size has something to do with anti cooling. you wan just the right size. too small, your choking the engines performance. too big, gases, bounce around, and cool down, and not flowing as quick as they should.
on a stock/modified motor, somewhere around 1 1/2" to 1 5/8" pipes are good.
a cross pipe helps bottom end even better
even in your “set-up”, power gains could be had. BUT, if yall want power, why aren’t you doing more then 5000 RPM?
you can have the worlds best flowing exhaust system, but still be choking your engines power with stock manifolds.
thats my opinion. you can either listen to it and reply nicely , or eat it.
Car manufacturers are under extreme pressure to wring every fraction of a mile per gallon out of an existing engine configuration. At the same time they want to control cost. So your exhaust system already produces the best fuel economy for normal driving.
Adding exhaust modifications MAY increase power but will not likely produce ANY gains in fuel economy.
P. T. Barnum never said that there was a sucker born every minute. That appears to be out of character for him. He probably would have used “customer” instead of “sucker”. The real story is a lot more fun, and Barnum is at the center of it:
Eat the reply?,surely you jest-this forum is about exchange of ideas and experience.I post to learn something,a fair amount of new vehicles I’ve been around have been governed to not much more then 5K.I dont want to spend $1000 to gain 8HP at 6000 rpm,I say there is no replacement for displacement-Kevin
thank you for replying nicely. overall attitude on the forum isnt so great.
i see where you are coming from with the rev limited thing. although, you can reprogram most engines’ limiter. (should be) one of the first things that gets changed. most headers create better power throughout the powerband, and not just limited to 6k+.
Thanks for the nice reply roadrunner.I was losing a race to a Toyota pickup by a suprisingly small margin one day in my 99 Nissan Frontier(Auto, bigger tires then stock,probaly 20 rated HP less then the Toyota) the rev limiter on the Nissan started kicking in at 5500 Rpm.I figured the Toyota would have walked away it didnt (it was barely faster)I still won the race by taking a chance.I feel the Nissan had a horrible exhaust system,my brothers Tundra sounds incredibly free flowing-My question to you is-How do I do away with the rev limiter?(My current Dodge 3.7 will spin to 7K with no problem)-Kevin
Kevin,
I’m glad you enjoy racing. But I get the feeling that you are street racing. If so, please take it to the strip. Every so often someone dies in this area because of street racing. The last time it happened, the racers were just fine. But several onlookers were killed when one of the drivers lost control of his car. Drag racing is a lot of fun, but it is dangerous, too. When you are going fast it’s hard to react to anything on the road, especially if you are intent o winning. And who wouldn’t be in a race?
Well actually I dont, this was a rude guy who wouldnt let me in the lane I needed to be in(A lot of drivers in this area act like they dont know what signal lights mean) and JT you are right-never street race,calmer heads should prevail.This is one reason I dont own fast vehicles,the temptation gets to great for me-Kevin to resist sometimes
I have a hard time believing that your Dodge 3.7L spins to 7k without flying apart . The redline is around 6000(though the tach doesn’t always have it indicated) IIRC. I would wager that the rev limited is set either at the redline or possibly a hundred RPM or so over the redline.
you cant get rid of a limiter easily. but you can reflash the computer, to bump up the limit about 1k or so. at least, on an LT1 chev you can.
Good man, Kevin.
“A lot of drivers in this area act like they don’t know what signal lights mean”
Sure they do. It’s a challenge! You threw down the gauntlet, and had the audacity to take their God-given space!
Sadly, it’s been that way in the DC area as long as I’ve had a license. Even in the late 60’s I learned quickly not to use my signals to show my intent to change lanes. Most people just sped up to cut me off. A friend moved from NYC to DC in the late 70s and was appalled at this practice. I told him to just get used to it and stop using the turn signal. And things haven’t changed for the better.
Whew man you said it,I believe in courtesy-Cant believe how many out of town ladies are amazed when me or one of my friends hold the door for them.I’ll tell you a disturbing trend,I watch people in Lowes,Wal-Mart,you name it-they would stand in the aisle for five minutes,rather then say"pardon me or excuse me" so they could get by someone.People are losing communication skills rapidly,same deal with the rude cellphone or cold shoulder snub.(I dont hear the best anymore.if I dont speak to someone,its either because I dont hear em’or see em’)-Kevin
Thanks, dont believe I want spin it any higher(I was growing a bit concerned,dont believe I’ll run it that hard in the future)-Kevin
FoDaddy thanks for the reply,I had no idea what the redline was on that little mill.I’ll take it a bit easier in the future on that critter(brother had a"Windstar" van that would cut out at 4500 RPMs in nuetral.Did Dodge design the 3.7?-Kevin