Just curious what exactly does it do? When it comes to performance I always hear say the less back pressure you have the better and then some people say you need a good amount of back pressure for the engine to run so I was wondering what is back pressure and how does it effect the engine?

Thanks,

Chris

 

let me take a wack at it...

Backpressure... Think about your engine being an airpump.... as the cylinder goes up it compresses air and atomized fuel... then the spark plug ignites it and the slow explossion pushes the piston down with force... this force is what moves your car forward... now all that burnt fuel and air is EXPELLED through the exhaust manifolds.... they are only so big.. but that spent fumes are pushed/forced passed the opened exhaust valve and into the manifolds all the way to the tail pipe...

This happens quickly and if the exhaust pipes are small the gases get pushout by the cylinder really hard and they get can not get out fast enough.... the gasses get compressed and it takes engine power to compress them out the cylinder.. therefore power loss... plus then new air/fuel mixture is then sucked pass the intake valve... this also takes engine energy... now if the spent gasses can not get out fast enough...and get compressed in the manifold... some of those gases either return back into the cylinder of never leave... this useles gasses take space in the combustion chamber and displace some of that new air/fuel mixture... the final result is that you get less power cause you cant cram enough air/fuel to fill up the combustion chamber...

if your exhaust pipes are not restrictive then you can get most of the spent gasses out the cylinder and then you can refill it with fresh air/gas and the more air/gas you can pump into the cylinder the more powerfull the combustion will be.


I hope I made sense...

marvin

 

You did. Good explanation.

 

Thanks.

 

Dude I am sooooo Jealous!!! thats a sweet ride. A chick Liar fer sure..

A question for you... I saw the speaker and amp set up you wanna install back there... Do you wanna lay your chick in the rear seat or are you gunna Gut her out??

GAWD D.A.M.!!
that thing is gunna rock ther guts out man!!!


I really really dig the interior lights but the outside lights?? Get a video camera..... I am sure you will see some Tuna Canned Import guys wreck themselfs off the freeway at night out of pure Jealousy!!! (grin) I think they were too much though... but then I am 40 now so I guess I qualify as an old gizard already.


I like yer ride... is sweet... mine needs paint already so no pics from mine till she is shiny again.

Marvin

 

Thanks.

I'm lucky, my car got repainted not to long ago before I brought due to the fact it was in a wreck. So they ended up repainting the whole car. As for the sub setup I'm not sure wether to toss it in the back seat or get a dB gain and stick in the trunk.

 

is 0 back pressure good or bad? I could sworn I read somewhere you lose some power when ur exhaust is too free flowing and you needed to have some back pressure. If so why?

 

Contrary to popular belief, that is an untrue myth. I know of NO test conducted that supported the claim that backpressure is needed or necessary for anything other than lowering the torque level. However, resonance tuning IS necessary to optimize the exhaust system. This is where having the correct size tubing, for a given application, is required to obtain the most torque from the system as possible. With the IC engine being a glorified air pump, backpressure is the enemy, regardless, of the vehicle application. I challenge anyone to produce a documented, properly controlled test that legitimately supports the contention that backpressure itself, is good to have, or necessary, for otimum torque.

 

Thats a no brainer dude

 

He he I know, I want see if it actually can move my top once I drop it.

 

I agree 100%. Judson Massengill of School of Automotive Machinists does too!

 

Think about, it dosen't make any sense! If an engine is an air pump, then thefast you get air in and out the more powerful it is. I could never understand this argument because it just isn't logical!

 

Well,
I ran with no muffler and lost .4 sec consistantly. I wasn't able to hook hard enough (power problems).

I have a feeling that a converter and higher shift points would have turned that -.4 into a + .1 (plus whatever the converter would have gained me)

 

Use trap speed, not elapsed time, as an indicator of horsepower. What was the difference in trap speed muffler vs. none?

 

Then what do they mean when they say piston scrapeing?Isn't that when the exhaust is too free flowing where you can actually loose horsepower?I dunno.I read this somewhere.Just wondering.My02