[Merged] About Headers

FendeR_21

driving a car with modified headers is cool coz ur car goes fast without exerting too much stress on the engine and your car breathes easily they say. Question is do they help you save fuel or do they make your car gas guzzlers? They say it helps others say its bad for your fuel economy. Please help coz im planning to install one, like my bro's Civic by the way, is there any headers out there that are not so loud?

jason_10

first of all, installing just the headers wouldn't do much. you must install at the least is a modified intake, bigger pipings and an aftermarket exhaust system in order to make the most out of the modification.

with more air coming into the engine, the ecu has to compensate for it and provide more fuel. so there goes your fuel economy.

lastly, its not the headers that's making all the noise but the muffler. you can choose from a freeflow or a chambered one. the latter producing less noise, which is better imo.

slamm

With the basic mods like I/H/E, the fuel consumption will still be dependent on the driving style.

As mentioned, headers aren't loud, that falls to your resonators and exhaust piping already.

sweetbaby!

Hello there! Just a question from someone who has no clue about it.

I want to have my car installed with headers (and a lot of people are asking me to also...)

But of course, it's my car and I want to make sure first before
investing on something like that.

So please tell me:


* What are the advantages and disadvantages of having one?
* Will it add speed and power to my car?
* Will it damage my car if wrongly installed?

Other experiences and inputs will do. Thanks!

NOKiE

http://auto.howstuffworks.com/question172.htm

slamm

The link above explains it well. Just be aware that the power gains will depend a lot on the header design, especially since what we have locally are "mano-mano" designed headers sold by most local muffler shops. These are assembled by hand with a crush bender and black iron (or stainless steel but it's more expensive). The imported, mandrel bent headers cost much more but are much more well designed for optimum gains.

We have Mufflerland 4-2-1 "mandrel bent" (daw... it isnt crush bent but it doesnt look to be fully mandrel bent either) headers on my younger brother's Nissan Sentra. Although the power gains have not been measured by a dynometer, SOTP feel saw the car breathing better in the top end, above 4k rpm to redline... and this came about noticeably when we coupled it with a free flow intake.

It won't damage your car, it will add power if you have a good header, if its coupled with a freer flowing intake, and of course granted your engine is in good running condition. Fuel economy will suffer only if you find yourself flooring the pedal more because of the newfound increase.

My .002

D'Transporter

It's a very popular bolt on application that gives you a significant and noticeable power gain. The sound can be very loud for others specially if you have an automatic. I would prefer installing it on a stick shift than an automatic car. Expect some loss of power in the low rev range (1 to 2500 RPM). For a natural gas engine I would prefer 4:1 configuration compared to the 4:2:1. Install a cold air intake and an adjustable fuel pressure regulator to spray a little more fuel to compensate for the additional volume of air pushed through the system.

jason_10

fyi, adding just the headers won't affect the sound of the exhaust. and yeah, using it on an a/t car is kinda useless.

cynicsweet

4-2-1 headers will give you better midrange (rpm) gains, better for everyday use; while 4-1 headers improve high end (rpm) gains, better for drag racing.

sweetbaby!

Thanks for the inputs, guys!

D'Transporter

jason_10 wrote:

fyi, adding just the headers won't affect the sound of the exhaust. and yeah, using it on an a/t car is kinda useless.

Believe me, you are going to get an additional sound directly from the headers reverberating into the cabin and yes it's not useless in an automatic.

jason_10

the sound your hearing might be coming from the intake (probably caused by the increased exhaust velocity). last time i checked there are no holes coming out from the headers itself where any audible sound could emanate. probably vibrations, but sound i dunno.

and imo, installing it to an a/t car is useless.... from a drag racers' point of view, you wont be able to maximize the hp gain since you won't be able to launch a car the way you do with an m/t. plus you won't be able to determine the optimun shifting points. the computer does it for you.

anyway if you insist to have it installed on an a/t its possible (it even makes the engine bay look mean). its just that you can't maximize its potential.

brock

so what shops are the best for headers installation. is P7500 enough for headers + piping?

rational

Does having a catalytic converter negate any advantages of having headers?

If all of the exhaust has to go to the catalytic converter anyway then wouldn't you in effect still have the same back pressure?

slamm

jason_10 wrote:

and imo, installing it to an a/t car is useless.... from a drag racers' point of view, you wont be able to maximize the hp gain since you won't be able to launch a car the way you do with an m/t. plus you won't be able to determine the optimun shifting points. the computer does it for you.

anyway if you insist to have it installed on an a/t its possible (it even makes the engine bay look mean). its just that you can't maximize its potential.

I beg to differ on this... FYI ours is installed on an automatic car (GA16DNE engine with a/t) and i find no point to your saying it's useless because the engine now breathes freer, whereas, before it was more taxing on the engine to bring the car over 5K rpm because of the restricted stock exhaust (and intake). Now the car goes up easily all the way to redline despite the fact that it has taller gear ratios brought about by the 4 gears of the a/t and i find this pretty useful when i drive on the highways.

In fact, it is also useful in a sense that it can help make up for the bigger power loss an a/t tranny gives between the crank and the wheels because of the torque converter.

On fuel economy, we averaged 8km/L prior to the headers and intake install... afterwards, we still average the same fuel economy with the same driving style (this is with 4-2-1 headers BTW). It's with the way a car is driven that matters more with fuel economy as these are just basic mods that's not affecting your engine displacement, vehicle weight, or gear ratios amongst some. It may be slightly affected if your headers gain more on the top-end (i.e. 4-1 headers), as higher top-end power usually sacrifices low and mid range power/torque (which favors fuel economy). Yes the ECU will adjust to more air coming in and out but the engine ignition rate/cycle brought about by the stock fuel delivery system and stock internals will still remain more or less constant.

The noise brought about by bolt-on mods is usually because of:
- the aftermarket intake (which only comes out on full throttle usually)
- the exhaust piping (and it's resonators)
- muffler design
With our case the exhaust note on our car, which had a Trust JASMA-spec muffler, improved (became quieter on idle and got a lower exhaust note when the throttle was applied) when the headers we're installed.

My .0020

PS: on the local header shops, try looking at SMT (Makati) or Mufflerland. I wouldnt recommend Freemuff and Nodalos much at this point based on what i've seen. I'd also prioritize getting headers and an free-flow intake over the piping and muffler if the budget is restricted.

jason_10

sorry i was seeing things from a drag racer's point of view. yes of course there will always be gains, but the response from an m/t is better because the gain in power is more usable and controllable, imo.

@rational,

afaik, it depends on the diameter/design of your resonator. if its 2", all the pipings must have 2" diameter all throughout.

if your on a budget, fremuff is ok. just make sure you get the right specs on your car. on my civic before, i used a cast iron headers from fremuff, paired with a 5zigen pipings and 5zigen border muffler. it didn't stop my sohc non vtec civic from clocking 15.3 secs.

slamm

jason_10 wrote:

sorry i was seeing things from a drag racer's point of view. yes of course there will always be gains, but the response from an m/t is better because the gain in power is more usable and controllable, imo.

NP dude. We just have to be aware that most applications discussed on the thread most likely refer to "normal" road driving.

BTW, Mufflerland usually gives good discounts on their headers during motorshow displays (usually at the Trans Sport Show and Caltex Delo Sport Truck and Custom Car Show).

rational

jason_10 wrote:

@rational,

afaik, it depends on the diameter/design of your resonator. if its 2", all the pipings must have 2" diameter all throughout.

The more I think of this, the more I'm convinced that to get any effect from the headers, you must remove the catalytic converter. If you cut open a catalytic converter, you'll find that there is the monolith catalyst support which consists of a gazillion little channels. The catalyst is coated onto those channels. I'm sure the pressure drop is enormous. Even if the total effective diameter is 2". the surface area of the channels are much greater than in the piping.

IIRC, that's why there was a big drop in power when they first introduced catalytic converters.

Then again... this is all theorizing on my part. Does anyone have any data?

brock

jason_10 wrote:

if your on a budget, fremuff is ok. just make sure you get the right specs on your car. on my civic before, i used a cast iron headers from fremuff, paired with a 5zigen pipings and 5zigen border muffler. it didn't stop my sohc non vtec civic from clocking 15.3 secs.

i'm curious about your i/h/e. i'm planning to install it on a sohc vtec civic. so fremuff cast iron headers + 5zigen piping is ok. gusto ko sana setup to match a stock sir.

jason_10

my intake back then is knn and iceman tube, fremuff 4-1 headers, size of the zigen pipings is 2.25" and zigen border muffler. what's good about this setup is that there's still torque in the midrange and still have power on the high end. (this setup complements my other engine mods)

to match an sir, you'll have to do a lot more to the engine than stage 1.

brock

moving from 3k-5k rpm is slow compared to 1-3 and 5-7.

kahit 125hp-140hp increase oks na sa ken. lagi ako tinatabihan ng sir e. naka full wrap around bodykit kasi ako.