OBX cat-back exhaust

[Kevin]

Originally Posted by secondchance

At 6000 rpm, 1st gear, factory registered 1.4-1.5 psi. OBXregistered about 1 psi.
As for the sound it's very mellow.No resonance at 6th gear crusing.
I am very pleased.

next time i'm in dc i'd love to hear your car

[MikeGolf]

Originally Posted by secondchance

At 6000 rpm, 1st gear, factory registered 1.4-1.5 psi. OBXregistered about 1 psi.
As for the sound it's very mellow.No resonance at 6th gear crusing.
I am very pleased.

Did you hook them to stock manifolds or after market headers?

[Corbusa]

wow that seems cheap. Is the quality ok ? I might have to pull a 3rd shift and get this..I also see they have the ZR headers too..
http://www.ebay.com/itm/OBX-Exhaust-...item2317995684

[secondchance]

Jeff - I think OBX is less raspy and more mellow, bassy sounding. About the same or less loud.

Kevin - next time in DC area you are more than welcome to drive my car.

MikeGolf - I am running OBX headers.

Corbusa - quality is as good as OBX. The whole system is polished SS.

[MikeGolf]

Would they hook up with stock manifolds? Thanks for the help but for the price it makes you wonder. I will do the headers later in year but with the coating and everything, I'll need an exhaust system first.

[secondchance]

Originally Posted by MikeGolf

Would they hook up with stock manifolds? Thanks for the help but for the price it makes you wonder. I will do the headers later in year but with the coating and everything, I'll need an exhaust system first.

Yes it will hook up to the factory system - at least it would have for my 94. Driver side will hook up with 3 holed triangular flange and the passenger side will mate w/ 2-3/4"diameter pipe (factory size).

[Corbusa]

I have a few questions about the exhaust systems .. The OBX system for sale, will it fit right in place of the factory system or is major mods necessary ? When I do get the headers is there major mods needed there? Especially to hook up from the header flanges to the new system? How does it connect to the cat(s) or resonator..
Which part of the factory exhaust is the most restrictive ? Are factory old cats hard to get or expensive? I was thinking of getting old ones to hallow out so it looks correct yet can breath.. Any suggestions is appreciated..
FYI I am working day and nite to get my vette paid off asap.. But when cheap good mods come available I'll do what I can to get them and set them back for later.. any and all advise it really welcome...

[secondchance]

Originally Posted by Corbusa

I have a few questions about the exhaust systems .. The OBX system for sale, will it fit right in place of the factory system or is major mods necessary ? When I do get the headers is there major mods needed there? Especially to hook up from the header flanges to the new system? How does it connect to the cat(s) or resonator..
Which part of the factory exhaust is the most restrictive ? Are factory old cats hard to get or expensive? I was thinking of getting old ones to hallow out so it looks correct yet can breath.. Any suggestions is appreciated..
FYI I am working day and nite to get my vette paid off asap.. But when cheap good mods come available I'll do what I can to get them and set them back for later.. any and all advise it really welcome...

First my comments are based on my experience w/ 94Z. I believe 91 and up are close.

Both headers (OBX and SW) and cat back exhausts (Corsa and OBX) are designed to replace factory exhaust manifold and factory exhaust independent of each other - meaning connection points are maintained so the headers or the exhaust will mate to factory connection points and match the factory connection type (3 holed flange on the driver side and slip joint at the passenger side).
Both SW and OBX system does not account for cats. Factory manifold has cats very close to the runners. Headers, in order to maintain separation between individual exhaust ports, runners do not converge until the collector. If you need to splice in cats, cat has to be added after the collector. This means for SW, cat back exhaust has to be modified to splice in cats. However, OBX header collectors are about 12" closer to the motor and after the collector has a glass pack that mimicks spun metallic cat that slips on between the header collector and the exhaust. These pieces can be used as a template for metallic cats to be modified for splicing into the system. Also, this 12" closer to ports configuration would help in lighting off the cats and keep them hot.
As for which part of factory system is the most restrictive, answer is the rear mufflers at least for the later exhaust system. Early factory exhausts are restrictive starting w/ connection into resonators (a piece in the middle of the car).
If you intend to hollow out the factory cat for visual go with OBX. OBX already includes glass packs that visually look like aftermarket metallic cats.
Call me if you want to discuss or need more info - 703 980 8814.

When I get a chance to get my car on the lift I will take a few pics and post.

[secondchance]

Though it worthwile to add more detail:

I modified my exhaust in stages namely due to financial restrictions.
First mod was removing the factory exhaust manifolds including cats and installing OBX headers to factory exhaust - hp and torque increase was immediately noticiable accross the entire rev range. At idle the car sounded the same w/ factory system and at about 2000 rpm became slightly louder.
Then, I bought a pair of Magnaflow mufflers ($259 at Corvette Central) and replaced the factory mufflers - exhaust became a little loder but the car developed droning in 6th gear that gave me a nasty headache. These were removed and sent back to Corvette Central.
Finally I saw the OBX at an incredible price and had to try it - high quality and no issue w/ install - system, including headers, is a little louder and I can hear the engine pulse. Definate power increase over header/factory system at higher rpm and yet quiet enough for a normal conversation and, most important for me, no droning in 6th gear!

I sincerely thank Jim and David for helping and putting up with me going through all these variations of exhaust combo.

[Corbusa]

Thank You sir!, I'm going to see how quickly I can get started on mine.. I appreciate the info...