Stock Exhaust

[vettn71]

What does a 90 stock exhaust look like? Mine has two pipes from the catalytic converters into a premuffler(?) then into two mufflers and four rectangular tips. I know the tips are right, but did the Z have true duals?

[32valvZ]

Originally Posted by vettn71

What does a 90 stock exhaust look like? Mine has two pipes from the catalytic converters into a premuffler(?) then into two mufflers and four rectangular tips. I know the tips are right, but did the Z have true duals?

Sounds about right to me. The pre muffler as you say is called a resonator.

[tccrab]

If you look into the exhaust tips you will discover that the outside pair are not as dark as the inside pair.
That's because they're fake.

TomC
"Crabs"

[vettn71]

Thanks for the posts. I spent two evenings stripping aluminum paint from the exhaust and a thick layer of semi-gloss black from mufflers and tips. A previous owner must have "restored" it, as the paint was on pretty thick.

BTW, for "stainless steel" it's not very stainless. Any ideas on how to remove the corrosion without ruining the manufacturing marks?

Jim

[tomtom72]

My 90 still has it's OEM exhaust and my muffler cans came with black paint(?) on them. I think it's to make them "disappear".

I'm not positive, but is our system s/s? Maybe 2% if it is, or maybe it's an alloy with aluminium....

I know in a moment of guilt I attacked my front pipes with some Never Dull wadding & a costco m/fiber. It took quite awhile to get it to look like I was doing anything. I was eyeing up the Mothers Mag & Aluminium polish, but then decided that I drive mine too much.


Tom

[ZR1Vette]

The OEM finish for the tubes is natural dulling, but I found there were two ways from BG the cans and tips were finished... just satin/flat black at back of cans and tips or satin/flat black for entire can and tips...thus this pic>>>

[vettn71]

Mike,

Super picture. That is a lot flatter than I would have guessed. Most older (C3) use more of a semi-flat. Looks like high-temp Rustoleum flat would do pretty good. There was so much semi-gloss on the tips and mufflers that it had thick runs in it.

As far as the stainless goes, I was just quoting the NCRS tech manual which said all 90 & 91 C4s had stainless systems. I have quite a bit of corrosion on mine, so if is stainless, they didn't break the bank buying it. I was hoping there was some type of chemical that would remove the rust without wire-wheeling or sanding.

[ZR1Vette]

Thanks Vettn71...
Here is the mid pipe area at the rear hangers... there is some rust and discolorization.. but that obviously is where a weld site is located... are you just seeing wholesale rusting of the pipes themselves?
Also... not all SS is created equal... different grades so some more rust resistant and some also some higher SS grades are also brittle when hot.

[Aurora40]

Originally Posted by vettn71

but did the Z have true duals?

The resonator has two pipes going through it, though they share the packing material. I'd consider that true-duals with some crossover. They don't ever dump into a single pipe.

[Aurora40]

Originally Posted by ZR1Vette

The OEM finish for the tubes is natural dulling, but I found there were two ways from BG the cans and tips were finished... just satin/flat black at back of cans and tips or satin/flat black for entire can and tips...

Are you sure yours wasn't painted later? I notice the springs on your exhaust hangers are also a nice black, and you seem to have zero undercoating on the trunk bins? It looks to me like someone did some detail work on the underneath rather than that being stock?