Polished exaust manifold

[Mantis88LX]

well me and my cousin worked on my spare exaust manifold, i was hoping it would be the 4-2-1 desighn but later i found out they are only on the 88-89 lxis, so anyways we used dremels and shit and polished the insides really smooth and they look real damn clean too, dont know if i will ever try it on my accord but it didnt cost nothin,

what can be gained from doing this? hopefully a few more horses?

[Mantis88LX]

anyone???

[2Fast_Fiero]

I'm guessin just a clean stock flow, nothing you can notice because its a stock exaust manifold, You can't do anything to it.

[shepherd79]

polished exhaust, that is something you won't see everyday.
well, i would give you a few days before it will turn black and starting to collect exhaust deposits.
i don't think it will give you any performance increase.
do the same thing to the intake and you should have increase in HP.

[Mantis88LX]

polishing as in smoothing out the inside surface.

Honda performance guide = polishing smooths the path, reducing turbulence. thus letting air flow better

[A20A1]

+1
Good thing is though thats it's not +1 just @ peak power but it increases power along the entire powerband maybe by 0.1hp-0.5hp.

If you've ever looked at a dyno sheet... you'll nottice power climbs almost in 45 degree line as rpm increases and it slowly builds to max hp. if you can get the power to climb closer to a 90 degree angle, then you'll be a lot quicker.

[Mantis88LX]

so you think its worth it? i already have the begining of each port smooth as a babys butt, its gonna be my project for a few months just because im runnning out of shit to do so this should keep me busy for a few months

[A20A1]

Shine a flash light thru the bottom of the manifold up to the ports to help see what you're doing.

I'm curious to see if you are able to polish deep inside where the ports begin to merge

[Mantis88LX]

yea thats why im using a spare manifold so i can spend a few months on it, i used some really long dremel rock tools and go up in there pretty good, its pretty smooth im using ruff to fine sand paper and rolling it up and sticking it in one end and pulling it out the other and pulling it back and forth to smooth the hard to reac spots,

[Mike's89AccordLX]

I don't really think you'll notice a whole lot of difference since it is a stock manifold. (is it a stock manifold?) But it is worth doing a port and polish job. When I get my headers from pacesetter i'm going to dremel those puppies out. And also buy a test pipe for my cat. That's a bit illegal in MN. But it's definetly worth the hp gain. I put a breather K&N filter on my valve cover (looks tight as hell) : i'm not really sure if I got any hp gain, but I did notice my rpms move faster. I would keep doing what your doing b/c we might be wrong and you would notice a nice gain in hp. Good Luck! :rice:

[rocky2]

Mantis88lx,

I like your determination. If you want to gain some horsepower on intake side. Youd have to cut the intake manifold down the middle,and somehow make whole area the surface as a golf ball. The devits on the ball trap air and have less resistance to other air traveling by it. Then weld it back up. Air would flow real nice just as a golf can fly far though the air. But figuring out how to is tough. Also I disagree with those who said thered be no gains. Read Smoky Yulnecks secrets to horsepower,grind,grind grind.