Discussion Forum - Northstar Chevelle Club

SShink · 3K+ Club

Straight dual exhaust or H Pipe?

Dan Williams · Active Member

Stan, I have an h-pipe on the 71 and "true dual" on the 65. You might gain 3-4 horse, but I like the sound of the true dual much better but that could just be me. The h mellows out the lumpiness, but I love the rough sound of the other.

bowtie · Secretary

I can't comment on a performance difference, but I'd hate to see how lumpy mine would sound without the crossover.

OscarZ · Treasurer

I went from straight to an X crossover on the Cutlass I had and I liked the crossover. I don't recall any noticeable performance difference but there was a drone/harmonic that I would occasionally get with the straight that never happened once I had the crossover.

John D · 2K+ Club

I'm running a Pypes "X" setup on Blackie. Originally (with the 327) it had straight duals, that had a "rapppppyyy" quality to it, and a drone at a certain mph (luckily not at a cruise mph). When I went to the 383 and then LT-1, I installed the Pypes with Street-Pro's. Much quieter and "smoother" sounding at idle, but people tell me it's LOUD when you hammer on it. I can't tell 'cause the sound is 8' behind me.

Can't give you an eval on "seat of the pants" or actual numbers, as I've done too many changes for a baseline, and the car's never been chassis dyno'd.

Are you considering an exhaust "kit", where you'd be bolting it on?

SShink · 3K+ Club

John D wrote:
Are you considering an exhaust "kit", where you'd be bolting it on?

Here's what I'm considering for the H pipe version:

http://www.jegs.com/i/Dynomax/289/89023/10002/-1#

Here's the Jeg's (Walker Muffler) true dual version:

http://www.jegs.com/i/JEGS-Performance-Products/555/30551/10002/-1

John D · 2K+ Club

You know, it's a haul across town, but give consideration to the Midas shop in Shakopee. The guy who owns/runs it is a gearhead, and he saved me $100's on doing the "Green Mary's" exhaust.

They may be able to do a system "collector to bumper", done & out the door for less than your aggrivation is worth.

dashboard · 2K+ Club

Crossovers are nice until you need to drop the transmission.

X2 on the Midis in Shakopee he did our Buick, he has all the original bend cards; you drop it off, go back and pick it up later that day, no muss no fuss and for the same or less money, at least give him a call.

Lost in the 60s · President

An X pipe is more beneficial than the H. I have a Pypes X system on the Camaro and it is fairly quiet until I get on it and then, yeah, it barks....LOUD.

Chris R · 2K+ Club

Why not get another Pypes kit like you got for the green car years ago? Good kit for the money and its all stainless, not aluminized.

I also have another tip which is a less popular one. The cool thing has always been to fully weld the system front to back. Instead of doing that, use stainless band clamps instead. I used to custom bend and install exhaust at a shop in 2005-06 and there is no advantage to a fully welded exhaust system accept for the fact that your locked into a lot more work if you need to remove a transmission or mufflers, and to use clamps in some spots to remove parts while the rest is welded looks tacky underneath. Second, if you have a stainless steel exhaust system, you better have a welder with wire in it thats stainless steel as well. If you use regular steel wire you will end up with ugly rusty welds in a few weeks.

Not just any stainless wire, the best results when welding stainless is to use the exact grade stainless the pipes are made out of or you end up with welds with a different carbon content in the meterial then the metal the pipes are made out of and they still wont look right once moisture has its way. They will still hold just fine, but cosmeticly they wont be consistent.

John D · 2K+ Club

An option (credit to Derek) for an "X" pipe is to put a set of flanges at the entry to the mufflers. Pull the collector bolts, then the muffler flange bolts (12 total) and the entire center section of the exhaust is laying on the floor.

SShink · 3K+ Club

Enganeer wrote:
Um Stan how much have you put in so far? New floors, truck, body work, paint, top, etc...and now you're going thrifty on us?
SST is so much better down the road...those steel pipes will turn McRusty on you over time and just detract the apprearance.
Just sayin'

Those are all the reasons why I'm starting to be budget constrained!

I'm o.k. with aluminized at this point. Dashboard has an aluminized system on his Elky, and it still looks good after being installed a few years. Since I only put on 3K miles tops in a season, and it's usually not getting wet... should hold up good. Other folks have said stainless systems have more of a 'tinny' sound to them, which I agree from the Pypes system I had. I prefer more of a deeper tone as well.

Besides, if I replace EVERYTHING with new, what am I going to work on over the next few winters so that I don't get the itch to sell it!

-- Edited by SShink on Tuesday 30th of April 2013 04:31:02 PM

SShink · 3K+ Club

Thanks everyone for the input.

Right now, I'm leaning towards the Dynomax/Thrush system because:

-I like the Pypes systems (had one on the green '72 BBC Chevelle a couple of years ago), but it's over $100 more and I don't necessarily need stainless steel

-At a minimum, I want an H pipe to minimize the cackling and relieve backpressure. I know, I'm getting old and building the vert to be a cruiser.

-I'm sure the guy in Shakopee does good work, but it's not mandrel bent, which IMO affects performance (added backpressure at the bends where the pipe narrows)

-I really like the idea of putting flanges at the muffler to be able to drop the front part of the system when pulling the driveshaft or trans, so will have my local Midas shop install those

Thanks again.

Enganeer · Mega Poster

Um Stan how much have you put in so far? New floors, truck, body work, paint, top, etc...and now you're going thrifty on us?

SST is so much better down the road...those steel pipes will turn McRusty on you over time and just detract the apprearance.

Just sayin'

bowtie · Secretary

then you invest in cameras so you can take pictures of it.

Tim H · Mega Poster

your not selling it?

-- Edited by Tim H on Wednesday 1st of May 2013 09:08:06 PM

Bungy L-76 · Active Member

I have aluminized pipe on my 53 and it still looks silver after 14 years and it sits outside all the time. The plain steel turn downs are all rusty even though they have only been on there about half that time.

No sense in going stainless when you're going to sell it shortly after it's done anyway.

Lost in the 60s · President

Bungy L-76 wrote:
No sense in going stainless when you're going to sell it shortly after it's done anyway.

............

Jon H · 1K+ Club

Lost in the 60s wrote:
Bungy L-76 wrote:
No sense in going stainless when you're going to sell it shortly after it's done anyway.

............

X2

SShink · 3K+ Club

Jon H wrote:
Lost in the 60s wrote:
Bungy L-76 wrote:
No sense in going stainless when you're going to sell it shortly after it's done anyway.

............
X2

Ain't happenin' guys. Too much time, money, and the wife likes this one waaaaay to much!

Scott Parkhurst · Super Poster

I run the X stuff and you've heard mine a few times. It's an American Thunder deal from the X back...still one of the best deals out there IMO. Tony's pal Mike Norrie connected the headers to the X, and then the X to the rest of the system. Tight and right!