91parkave

iTrader: (4)

You could buy a j bend and 180 bend and y pipe for under 100 maybe 120 off eBay Just saying and go 3 inch

gilroy222

Ya I'll have to look into it more. To me it seems not worth the 50 dollar savings since them cutting requires more labour Id think. Oh well. So you say 3 inch even after the split? Or just to the split? I don't wanna lose any low end torque lol. I was gonna do 3 inch to the split then 2.5... I'm sure I'll lose a little torque but not as much as full 3.

blkchevyz

3 inch to the y then 2.5 would be plenty.

gilroy222

I thought so. You think I'll lose a lot of low end torque with a set up like that? And is there any advantage to buying say a zzp downpipe vs. Just getting a shop to put in a 3 inch pipe with high flow cat instead?

blkchevyz

i'm sure the exhaust companies did research and know more than i do, but i wouldnt think you would see that much of a torque lose going with 3 inch. got to figure most cat back systems are 3 inch, 3rd gen used that at 1/3 of the power.

even more so if your using stock manfolds and still have a cat, i would think that would be enough to keep velocity up.

gilroy222

Makes sense. So the downpipe thing then... would I be just as further ahead getting a pipe in there with high flow cat and leaving the res? Zzp downpipe is like 300 isn't it.

lVloses

iTrader: (1)

I have a 3" catless 304SS ZZP downpipe for sale over on GMLS4 if you're interested.

gilroy222

I would but I need a cat man. Thanks anyway. The only way you can get around it in Canada is if you get farm plates or your car is more than 15 years old. My truck already has farm plates so I can't do my car that way. We have yearly e-tests here in Ontario where they measure your co2 and carbon monoxide levels and ****. So I need to go highflow cat.

The other thing though is that I don't see the advantage of paying for a downpipe when I can just get my shop to do a custom 3 inch pipe with a highflow cat for cheaper probably. All I need to know is if I need that little section of flex pipe (or whatever it is) that's at the start of the downpipe.

91parkave

iTrader: (4)

The start of the downpipe is before the flex section right at the flange. So you will need 3' double wall flex section and 3' mandrel bend and a 3' flange to custom make it
..........or you could just buy one that's already made

gilroy222

How come I need a flex pipe though? All the downpipes look the same the way the exhaust enters, goes down on an angle then the pipe levels out. Maybe I'm getting the terms mixed up but on that straight section there is that cross braided steel section or whatever that's pretty small.

gilroy222

So I guess what I'm asking is what does that cross braided steel even do? The pipe is straight until the bend.

crich88848

My guess would be for thermal expansion and for engine twisting under throttle.

gilroy222

Ahh I see. Well I guess I'll price it all out tomorrow lol. Any suggestions for mufflers that sound good but also flow good? I've been taking a liking to dynomax so far.

crich88848

i was looking at the dynomax VT before i decided to go with the magnaflow catback. They look promising.

blkchevyz

i like flowmaster, i went with their 1 chamber race muffler, single in dual out. its very small and goes in right where the y-pipe would be.

save money only need 1, and dont need to have a ypipe.
lol



regarding flow, i dont see it being a restrictions all it is a big chamber with a < in it.

its not like the crappy f-body cross flow mufflers.

gilroy222

I talked to an old F-body guy today at his exhaust shop. He's the no bullshit kind of person and he claims unless i'm doing serious power there's no reason to change out the stock cat. He was basically saying a mnadrel bent cat back will be the best bang for the bung. I don't know who to believe lol. The reason he says buy a cat-back kit is because they usually do engineer the systems and are dyno proven. He has an older camaro that he dyno'd with different exhaust and there was a 2 hp difference lol. So He left it stock. He also did a chip foose charger a little while ago and the only reason they swapped out the cats on the car was to make the exhaust fit more snuggly so that it didn't hit on bumps since the car was lowered.

So idk, i'll probably just forget about the cat for now and do a cat-back.

gilroy222

I should mention that i'm not doing cams or intake manifolds or anything... so I can see his point where opening up my exhaust a large amount won't do a whole lot.

crich88848

Correct me if I'm wrong here guys, but the main issue with the down pipe is the u-bend, not the cat. And this is exactly why I decided to go with the magnaflow catback, because it was engineered and dyno proven.

91parkave

iTrader: (4)

You can only engineer so much knowing the magna flows bends and diameter we can improve or keep the same level of performance if you wanna do custom exhaust however they don't adress the downpipe the cat really isn't restrictive at most power levels that most of us will achieve. That main part that i see needing to be addressed is porting the rear outlet of the factory manifold if using a aftermarket downpipe.

gilroy222

Ya that's why I'll probly go with magna flow. Any experience with the SLP cat back though? Its a lot cheaper. Or where can I get a magna flow system cheaper?