does backpressure exsist in a v8 i know it does in the little ricers? but i was thinking of doing cherry bombs or even streight headers with pipes, but my friend brought up the point of back pressure and that i would have no low end if i went strieght out with no crossing, is he correct?

it does but why worry about it? theres no need to unless you use the correct diameter exhaust pipe. that and turbo applications

so it wont mess up low end? so should i do glass packs or can i go strieght what would have more power

Set your mind at ease, Glass Packs verses straight both will have the same flow. Glass packs in essence are a straight thru flow that has a side chamber or area that is packed with fiberglass or steel wool type of material. This design is for sound control only, and will not affect the flow to any degree. They will minimise the exhaust "POPS", or backfire "POPS" that can be as they use to say, "ticket bait". They also act somewhat like a spark arrestor. Glass Packs are not a chambered style design of muffler that re-routs the flow, or restricks the flow.

got ya thanks. so ill prob go with the glass packs. but no on the cros pipes then?

got ya thanks. so ill prob go with the glass packs. but no on the cros pipes then?

An X-pipe or H-pipe to what you are referring to most likely dont DEAL with backpressure they deal with the actualy FLOW of the exhaust gases and allow them to cross over to one another and project the sound waves to a more crisp sound wave which in return means better flow. WEITHER I got that correct I'm not 100% sure its been a while since i even thought of describing them. I can 100% guarantee this tho! It will give you more horse power and torque. In my opinion glass packs sound like crap, using a 2 chamber muffler such as Flowmaster...Knowing that your from nor cal probably near Sac Town the Flowmaster assembly plant isnt far! They are great mufflers have always used them and you get what you want out of them.

well i think im going to go with stright headers.. but i should cross them and i would get more power than streight back?

Stop the text message talk. I have to go back and read every excuse for English that you spew at least 3 times before I can kind of get the concept of what you're trying to convey. Yes, backpressure exists. Why would it be dependent on the number of cylinders?

In my opinion, glasspacks sound like explosive diarrhea. Sure, they flow nice, but so do nowadays mufflers. An X pipe, would be good, but an H pipe would be louder. And I would not advise running straight pipes. It's illegal.

im getting so many different answers about the back pressure what flows better x or H

IF IT WERE ME! Id get a X pipe they flow better...Better flow means more power. ya digg? YOU DONT need to worry about back pressure there are more ugly ducklings you need to be worried about. Especially your emissions and if you live in Sac Town you need to worry about Sac Town police. THEY don't joke around.

im getting so many different answers about the back pressure what flows better x or H

ok like lol wut u wanna do is just go get sum flowmastrs and some stax and just have em stiking out the bak right behnd teh cab. u have 2 cut sum wholes for teh stax, but it would look badass. that wood have zero bakpreshure.

just get a Z pipe and be dun wit it

im getting so many different answers about the back pressure what flows better x or H

ok like lol wut u wanna do is just go get sum flowmastrs and some stax and just have em stiking out the bak right behnd teh cab. u have 2 cut sum wholes for teh stax, but it would look badass. that wood have zero bakpreshure.

just get a Z pipe and be dun wit it

get a z pipe? give me a BREAK

im getting so many different answers about the back pressure what flows better x or H

ok like lol wut u wanna do is just go get sum flowmastrs and some stax and just have em stiking out the bak right behnd teh cab. u have 2 cut sum wholes for teh stax, but it would look badass. that wood have zero bakpreshure.

just get a Z pipe and be dun wit it

:laughing4: :laughing4: :laughing4: :laughing4:
Okay, That's enough of that.

Doug

A little backpressure can be a good thing. Helps scavenge the cylinders. Too much is bad but a little is good. Right now when I let off on the gas on the freeway I can actually hear the exhuast burble which is neat. I had the same thing on my 79 Z28 and it was awesome.

:D

ok thanks guys, sorry i didnt mean to cause chayos

It's all good! Welcome to the ECC

A little backpressure can be a good thing. Helps scavenge the cylinders. Too much is bad but a little is good. Right now when I let off on the gas on the freeway I can actually hear the exhuast burble which is neat. I had the same thing on my 79 Z28 and it was awesome.

:D

Haha, my car does that and I was wondering if it meant something was wrong... I'm glad it doesn't cause I think it sounds cool.

well if you have a air injection pump installed...reasoning being for that after firing is due to a faulty air injection pump! The un burned gas that left teh cylinder is getting burned up :P

Nope. Just a straight non-emissions 350. 80's truck block with camel humps. Stock exhaust manifolds and a leaky single exhaust.

could be ur exhaust leak but other than that still coo! I liked hearing my after firing puffs when my smog pump was defective!

At low rpm's no back pressure will allow more low end torque, because there's no resistance on your engine to breath the air it needs to burn the fuel. At high speeds no back pressure will cause your engine to have less horse power and more torque, that lowers top speed. When you have no back pressure you get more off the line power, when you have a good induction, getting enuf air through your carb, or throttle body. The X-pipe I have heard, with balance the pressure, between dual exaust because each side has different back pressure, & the x-pipe balances the exaust pressure, wich means more power. If you add some good mufflers like Edelbrock's Ti-Tech SDT 304's you will have some back pressure, but not too much. With high end heads, and good headers, you will see a nice gain, with great air flow, now re-tune your carb when your done-(Happy engine=Happy driver).

I have alittle more tech. info on this subject- & I have a LOT more tech. info.


"Backpressure and scavenging ability can easily get confused. [/U] If you build a system with no backpressure, you'll end up with a system with no scavenging ability. The trick is to find the fine balance between the two. The bottom line is on a normally aspirated engine, too big results in poor performance....practical experience has told me that."

"Scavenging has much to do with size and length of header runners but the size of the system beyond that may have some substantial impact as well."

"Cylinder Scavenging, backpressure etc all has to do with manifold/extractor/header design, once your past that point, you want as much flow as possible.
What some seem to overlook though, is that often header design needs to extend to well under the car depending on where in the rpm band you want to make good power."

In english please, how does a basic system using factory manifolds on a 305 with 2 1/2" pipes with X and flowmaster 40's would work, and will that suffice when a 350 (w/headers) is installed at a later date ? Thanks !

Your question doesnt speak english as well, but in shorter term if you go to big with a free flowing exhaust you will lose power in theory. So if you have a street engine mild build 1 5/8" headers then a x pipe and flow masters and teh x pipe in the correct location and wiht 2 1/2" exhaust tubing you will have no back pressure existant nor having air being sucked in into the exhaust being the scavinging effect so I belive.

-Anduh