okay found my original thread

https://rennlist.com/forums/928-foru...ght=84+exhaust

 

Iceman, nice clean setup. Great work, as always.

 

I have a cat with the exact flange from the stock 84 cat , with pipes that mate to the msds headers. in otherwords, it will be a drop in for the existing stock cat back exaust , if you want a cat for smog. for sale, $100 plus shipping.

headers help about 12hp as I have found several times with the early cars.

I think i got another 5hp with the equal length headers.

Mark

 

thanks again for all the replies.

Mark, is it a high flow CAT? would it still need collectors on the headers? can you post a pic? we do not have emission in my area so don't really need for that, but would facilitate the 'easy way' referenced below. and reducing emssions from my shark would be the responsible thing to do.


I am getting hung up now on taking the easy way, or the hard what that may offer a few more HP.

easy way: get a Boral CAT back. then cut my current Y pipe back and fab from headers/collectors to the Y.

hard way: try doing something like IcemanG17. thanks for finding that link. I think I see why I did not see that thread. you must ask the correct search question.

leaning toward the easy way. in part because my car is a driver and don't want too loud. and it sounds like spending a lot to fab an optimized exhaust for my car may only provide a very few added HP.

the issues I am seeing on Iceman's approach for my car are two fold. very limited mufflers in 3.5" and the single, small magnaflow he put in the rear would leave it way too loud. I suspect I would need one in the rear and another up where the CAT would have been to get the sound down to a reasonable level.

sounds like a Borla CAT back w/out a CAT would sound great and hoping not too loud. and if I get Mark's CAT, further reduce noise level. BUT I do like a nice rumble/growl.

but adding an SC is on my wish list for the future ... probably distant future. so going now with at least a 3" back would set the stage for that.

any one have a thought about using the Borla CAT back with a SC in the future?

 

My OB with headers dyno'd at 203rwhp. They sound great and she runs hard! You will love the headers!

 

You'd be suprised.

In run that exhaust on the street, its very respectable.

 

If you want to get idea of the gains you might look for a very old copy of vw-porsche magazine in which Greg B. upgraded a 4.7l US 16v car. I think he did the headers, big valves, S cams and extrude-a-honed the intake. Got it near 300hp as I recall. I think he did it in stages and did dyno charts at each stage. It may have been scanned and posted here somewhere.

 

well... headers finally installed.

now looking back at this and a few other header threads to figure out how best to complete the new exhaust. my headers terminate at a 70 degree angle, but some others I saw in threads terminate straight back.

anyone have ideas on the best way to proceed? I will be talking to Burns Stainless to fab something if I do not get any other ideas.

 

Huh. I'm pretty sure my header flanges are even and parallel with each other. Anyway, doesn't matter really. Take two 45* 3" mandrel bends and split them down the middle. Welding those together makes a Y. Make one leg a little longer for the short side. You could have Burns make you one, but you can do it yourself for half the money.

It would like just like mine, but you wouldn't need the 45* bends before the Y.



Or, you could buy a Magnaflow X off Ebay for $90. Just cut the inlets to the appropriate angle and stub some pipe on if you wanted to run duals.

 

123quattro.

your headers look like the ones VANSTER posted, collectors run straight back.

makes me wonder what the heck I have? but they bolted right up.

thasks for posting that X connector, had not see that. what I was hoping to do is run the headers into a 2in-1out magnaflow where the CAT would be. dual 2.5" in and a 3" out, then all the way to the back and maybe another magnaflow were the pumpkin would be to get noise level down to where I want.

keep those ideas coming.

is this a great BB community or WHAT?

 

My headers have 3" collectors. The Y I made is twin 3"s in and a 3" out. I have the smallest Magnaflow muffler on it. I love it, but it's not for everyone. It's loud.

 

strange. mine are even.....

 

I have the same headers on mine, I think they are 928 Motorsports.
He sells a X-pipe but I decided to make my own.

 

If you don't want them post a price

 

Andre. with them all bolted in? guess your avatar should be a clue to the seriousness of that question.

Brad,
yep mine look like yours. checked with 928MS, their headers have collectors that go straight back.

so now I wonder what kind of headers we have.

think I have found all the parts I need to build with from Summit Racking. won't look as elegant as what you did. but will have to wait for parts and the build for more pics.