i recently had a y-pipe made and the guy put a 2" pipe after the y which is restricting the flow. i went to another shop today and talked to them about it. they said you won't feel a difference with a bigger pipe. the engine is putting out about 250hp and the 2" just seams like it would make a big difference if i at least put a 3" after the y. pushing exhaust from 8 1 5/8" pipes into one 2" is a lot of restriction. i have a 78 malibu with a 150hp 305 2bbl smogger engine and a 2" complete exhaust. when you give it gas you can hear the exhaust blowing out hard as hell. do you think i'l notice a difference with a better y-pipe?

 

heres a pic of what i have now.

 

anyone...?

 

DUDE!!!!!!! That's HORRIBLE!!!

Who did that? Billy-Joe-Jim-Bob's Lawnmower Repair?

The guy at the second shop was right. Replacing the 2" pipe that's after that conglomeration will not help. Looks like the guy took several trips to Autozone with $50 and a box of crayons.

Did you pay a shop to do this, or was it a favor? Hell, even if it was a favor, the person that did it either doesn't like you very much or they own a Mustang.

I don't know what else to tell you except rip that crap out and shove it up the anus of the guy that did it. Although I don't think it'd flow well enough for him to fart through.

Get something else. Shop around and tell the installers EXACTLY what you want (i.e. NOT THAT!!!!!) before you pay for anything.

Sorry to give you the bad news, but that's the only news there is to give. The way that pass. side pipe is joined to the one from the driver's side is no different than the stock pipe. You'd have been better off hacking the stock one up. At least the smallest diameter those came in is 2-1/4"

 

i payed a guy $100 to do it. a freind asked the guy if he could do it to flow good and match the flowmaster 3" catback i have. he said he could. a guy i know has all of his stuff done there and he gets real good results. i showed it to him and he said that the welds didn't even look like his. we went back and aksed if he could do anything different and he said thats the only way it can be done. he also said if we took it off and returned it he would give us our money back. i'm probably going to get a different shop to do it and get my $100 back from the first guy. the second shop said you can't bend a pipe off of the passenger side header because it was too low. the 1st guy got one on the driver side fine by cutting the colector down about 3"

i might get some elbows or something and give to the second shop so they can just weld them on the colectors and not even hassle me about a bend like that.

 

oh yea, do you think i will notice the difference with a good y-pipe? about how much of a gain do you think i'l get?

 

Looks pretty cobbled together to me.

Get a y-pipe from SLP.

www.slpeng.com

 

i would like to get an SLP y-pipe but i don't know if it would fit with summit headers(yea, i know there cheap but i'm only 15 and don't have much money).

 

OH....... well that changes EVERYTHING!!!!!

Call Summit and tell that the headers you have. From what another guy said (actually a couple of them), Flowtech makes the headers for Summit. They just don't sell them as Flowtech's

 

so should summit have a y-pipe to fit them?

 

aj 92rs "Looks like the guy took several trips to Autozone with $50 and a box of crayons."




LMFAO

 

Where do you live? That is the most horsesh*t exhaust ever. A good Y pipe could be worth maybe 15 horse over stock. Please post the place you had that done so they don't claim anymore victims. If you live by me I can hook you up with someone who will put a Quality exhaust on your ride. PM me if interested.

 

Where in IL do you live?

Just curious

 

i live in centeral VA. i'm probably going to get some elbows to come off the collectors and give them to the second shop to do the work since they said they couldn't do it beacuse you can't make a bend off the colectors like that.

 

today i went to another shot and asked the guy what he thought. he said its not hurting me one bit. he said it gets bigger as you go back...but this dosn't make sense because your exhaust is only as good as the smallest part. i'm confused besause people are telling me it isn't hurting me and people are telling me it is. it seams like it is hurting me but i don't realy know that much about exhausts. he said i can burn up valves with not enough back pressure. everyone on here says back pressure is bad and it makes sense. what should i do? i'm about to spend $40 on a back pressure tester to find out how much back pressure i have.

i'm not woried about a couple HP, but if it will help me a lot like 15+hp i will get it changed.

edit:and on the picture the 2" peice is pushed in about 3/8-1/2" on the bend

 

Those welds are nasty and un-even. It looks like a stock Y-pipe, except uglier. I'd say get it redone, it would help a lot.

Backpressure is an enemy up to a point. Too little backpressure and you can end up burning up your valves. Backpressure is needed for something called the scavenging effect. Basically, it helps pulls the intake valves open as the exhaust valves close. This frees some power, helps with gas-mileage, and reduces wear on the valvetrain.

 

i might try to rend a back pressure guage tomarow, what should it be?

how little back pressure it to little? if it was to run open 1.5" headers would that be to little or would to little be something like 2" primaries? please define how little is to little, thx

 

IF your motor is not a full race motor IT NEEDS BACKPRESSURE. If you eliminate all back pressure your car will slow down. Remember it's average power not peak power. I think I would get it changed because it look horrible but I don't think you'll gain 15+ HP. Find a custom shop or someone with a REALLY nice car and ask them where to go. I've never seen ANY set up on our cars, no matter what headers you have, that exhaust can't be bent for. Good Luck!!!

 

if i test the back pressure what should i look for? how much should there be and how should i check it? like reving it in park?

 

The only tester I've ever seen is one that messures temp. And you messure before and after a restrictive point after the car is warm at idle. If you have a hot spot before an area you're concerned with, then it is presenting significant restriction and needs to be fixed. This is the only way I know. Hope that helped

 

No engine "needs" backpressure. Backpressure is the demon to HP and efficiency.

You're getting scavenging mixed up with backpressure. Running too large of a pipe(s) can reduce scavenging because the exhaust has to be forced out by the pistons. To keep scavenging up the pipes have to be just the right size.

Backpressure is restriction. Plain and simple. It's bad, it's not needed, and it's never good. A small amount won't restrict as much as people think it will though. There's a fine line of what's great, and what's acceptable.

As I said, if the pipe is too large, and the exhaust just "lingers" there, it has to be forced out by the pistons. In a way that is also backpressure. It causes pumping loss just the same. One of the main problems with exhaust not moving fast is it starts to cool. Once it starts to cool, it becomes more dense. The more dense it is, the harder it is to move. That's why you don't want to go overboard with pipe size.

Think about it. If bigger was better, why do 99.9% of heads tested on a flow bench flow more on the exhaust side when they're hooked to a header than if they're vented freely? Scavenging!

From what CHP said about backpressure.

0-2psi ......... Acceptable exhaust backpressure

3-6psi ......... Mild backpressure; power improvement possible

7 or higher psi ....... Excessive backpressure; significant power improvement possible

"1psi of exhaust back pressure = 2.5% loss of horsepower (approx.) This means if you have a vehicle that has 170 horsepower stock, and have 0 psi back pressure-You will not gain a single amount of horsepower by spending hundreds or thousands of dollars on a performance exhaust system. If you have 5 psi back pressure, you are losing approx. 21 horsepower."

 

i think it is somewhere in the 7+ range. its not a stock engine and it makes the most power around 5000. its got good flowing heads with 2.02/ 1.6 valves and a decent street cam. my dad has a laser thermometer thing, should i try that and see how hot it gets aroung the restrictive area? about how hot should it get at the y on a normal engine?

 

i hooked up a compression guage to the O2 thing on the drivers side and when i reved it up in park it went up to about 5-10psi. when it was idleing it just jumped around the width of the needle. is this to much?

 

i checked the temp of the pipes, the 2" gets to about 210 after a few mins and the 2.5" gets to about 190. is this enough to tell if it is restricting at that point?

 

That doesn't sound to bad. If you don't mind the way it looks I'd ave your money for motor mods. Also remember that the 2 into1 y pipe offer better scavenging and that really can't be measured anywhere but on a dyno so maybe in the future, when the motor is built you might consider a true y pipe system. good luck!

BTW remeber the exhaust will get cooler as you move away from the motor. That is prob the difference you are seeing.

 

i'm probably going to get a backpressure guage and test it just to be sure of what i have. it just seems like a hell of a lot of restriction with the exhaust going through a pipe that you can put your fingers all the way around. if it is around 10 psi than that is way to much.

 

Why dont you just cut that y- pipe off and take it back to get your $100 back, and sell your present haeders, so that you can get a better header and y-pipe setup? I know it will cost you more money in the long run but it would be worth it IMO. And beleive me, I know how it is to be working with a limited budget. I am sure some of these guys on this board can suggest a good priced system with better flow capabilities.

 

i think that would be a good idea, i was thinking about the hooker 2055s. i can get $100 for y-pipe, but the headers are $80 summit headers so if i could find someone who would buy them it wouldn't be for much. so i would be down about $200 if i got the 2055s or hedmans. are there any cheaper headers that come with a y-pipe? i should be getting about 1200 when i sell a malibu i have but i don't want to spend it all on that.

 

I think you can get the Hedmans w/o AIR and the Y-pipe for around $200 from Summit or Jegs.

 

i got a better guage today and tested it in park. reving it up to about 5500 at full throttle a few times it got up to 4.5psi. i need an all metal adapter before i can test it driving. do you think it would change driving it? also, that was in the driver side header, not the passenger that comes into the T.

 

i think i'm going to get the hedmans for about 210 and just take back the y-pipe. i found them in jegs but i can't find them in the sunnit catalog or on there site. the part #s for jegs are 500-17470 for the y-pipe and 500-68470 for the headers. do you know what the # is for summit and if they have it? i want to order them from summit since i have always got my stuff within 2 days every time i have ordered from them.

 

haha You think his is bad you should see mine. I want to get the mufflex Y pipe but does anyone know of complications I will have? Also how big can I go with the I pipe? I have a flowmaster catback that I want to retain (well from the muffler to tail pipes anyway). Will making a tranny mount bar with dips in it for the exhaust work? thanks in advance