FAQ: Down Pipe Questions (Series I SC)

Not sure about attaching the downpipe to the manifold, but I found a mom/pop muffler shop in the country that welded in my reducer pipe and a piece of straight (4 welds) for $15. I gave them $20.

I can't see it being more than a $50 job if you supply all the parts.

also with the reducer would i want the down pipe to fit into it? same question with the other side? for example 3 in downpipe into reducer which goes into the 2.5 exhaust. sorry the question isn't too clear. It would be much easier to show in person.

So to get a shorty 3 in downpipe in ill need to buy the down pipe, a reducer, and a gasket? What gasket do i buy? do i just get the one that i can order with the downpipe or will i need to use something else to seal to the 95 manifold? I want to get this all figured out before i buy it and take it to a muffler shop. thanks for any help

Im in a bind. I need a dp for 95 riviera cant find a df cat locally only universal one but the dp is the problem wat can I do to fix the my problem

Ack...I know this won't help you at all but the exhaust is about the only thing i didn't save from my old Riviera when I parted it out...

I hope someone has a solution for you.

wats wrong with it?

when i tighten up the bolts and springs it falls off the donut tryed new pair it does samething even with new dount.

I am not getting this? just weld her up!

Pipes wrote:

Im in a bind. I need a dp for 95 riviera cant find a df cat locally only universal one but the dp is the problem wat can I do to fix the my problem

Rockauto.com starting at $128.- for the cat & downpipe (for a Bosal direct-fit)

Or local exhaust shop if you want,

It sounds to me like possibly your flange is rusted where the springs make contact . You may be able to use a couple fender washers between the spring and flange to secure it.

Try adding a few big washers to the flange if you can. You might be able to match up the spring-bolts with a longer spring-bolt at an auto parts store with a good selection, put a nut and a few bigger size washers on the back of the flange.

Otherwise try car-part.com for a good selection of salvage yards.

I have found this down pipe/ catalytic converter combo made by magna flow. It is supposed to fit with 95 rivieras. I am not aware of anyone on the forum using it, but it may be of nice.
http://www.autoanything.com/exhausts-mufflers/77A4168A3247727.aspx

I can't exactly tell from the angle of the picture, but it almost looks to me like the bends in the magna flow down pipe are less "pinched off" than the stock down pipe. I wonder if this could actually help reduce some KR. Any ideas from anyone? If so this would be a nice upgrade for series 1 owners who want a direct bolt on down pipe.

I wish i knew how a 3 in down pipe would affect a series 1 engine. It would be so much easier to create and install than custom headers, not to mention cheaper. Do we know if the stock down pipe is actually a restriction on the series 1, and if it would lower KR?

Bump!
Maybe I missed it, but I read through this whole thread.
What are the 95 Series 1 SC guys doing for aftermarket downpipes?

Any experience with this one??
http://www.autoanything.com/exhausts-mufflers/77A4168A3247727.aspx

I have not been able to find even one example of a different down pipe being used on a series 1. I was hoping to go this route as well.

The recurring statement I've seen is that unlike regals and the like, our downpipes were not actually a real restriction. That being said, I think with heavier mods it'd still be a good idea and obviously if you're at the stage of custom headers maybe it'd be about that time haha

Hope you're not reading that around here. My opinion is the downpipe is the single biggest restriction in our exhaust. Downstream the cat, our pipes flow pretty well, though.

What's your opinion on that bolt up dp in mine and Greg's links up there? If you don't mind me askin haha

As I recall, this is the DP and Magnaflow cat that fit the Series II, that I have on my 98. Looks like Hogan only has an Ebay store now. I'd suggest contacting Curt Hogan thru his Ebay store and ask if he can do anything for your Series I cars.

http://www.ebay.com/itm/DP10-3-Down-Pipe-and-Cat-97-03-H-Body-Bonneville-/300082544178?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item45de503e32

llamalor2112 wrote:

What's your opinion on that bolt up dp in mine and Greg's links up there? If you don't mind me askin haha

I don't see any specs listed for pipe ID at all. Hard for anyone to give much of an opinion from looking at their picture. And that is not a known supplier in your link. I wouldn't spend a dime there. Odds are you'd end up with something that required custom work to make it fit. JMHO

I think it would be worth a call the AutoAnything to see if they could provide the inside/outside diameter of their pipe. Might be a new discovery, or it could be not worth buying.

True.

Reading back thru the first 2-3 pages of this thread, it seems to me the ZZP 3" DP is the way to go though.

throwin my 2cents out dere,imo the biggest restriction on the series 1 is the rear manifold.it is a convoluted piece of confusion.you have the gasses running and colliding with each other and all kinds o problems going on there.gets real hot too! hotter than it should.
it is super complicated to do because of the very limited space down there.of course you would have to be able to weld and fabricate.there are header kits and various steel bends available out there to do anykind of header you want.but ya gotta do it yerself. no support whatsoever for the series one aside from huge engine mods and a few other little inconsequential bits..

if you go to westcoastFieros.com the dude over there sez he can fab up a header plate whereby you can then fab up your own rear header.He is a pretty cool guy and doesnt mind talking things over.i bet you could maybe talk him into fabbing up a rear header for the series1 Riv,provided he has one to work on

Summit Racing has the same Magnaflow part # 23404 for the same price, also free shipping free handling. I'd order from Summit if going with this option. Looked at Magnaflow site and didnt' see pipe ID specs either. They call it a "Universal Fit" part.