OBX catback exhaust

**abbezr1** · 01-27-12, 06:16 PM

Has anyone tried the OBX Cat back system yet on their zr1? I see that it is a 2.5 system. Is there any reduction in hp or torque over the factory system. There are some good prices on this system about 300. cheaper than flowmaster and 800. under B&B and corsa systems. How do they all compare? Thanks for any info.

**catbert** · 01-27-12, 07:37 PM

I've seen and heard conflicting reports on these systems. That's not good, because most guys think their systems are the best thing since sliced bread.

**Scrrem** · 02-03-12, 10:01 AM

Originally Posted by abbezr1

Has anyone tried the OBX Cat back system yet on their zr1? I see that it is a 2.5 system. Is there any reduction in hp or torque over the factory system. There are some good prices on this system about 300. cheaper than flowmaster and 800. under B&B and corsa systems. How do they all compare? Thanks for any info.

There is member here in VA that installed the OBX headers and exhaust on a 91 ZR-1 and loves it.....no issues with installation, looks and sounds great.
Rich

**abbezr1** · 02-04-12, 05:34 PM

Originally Posted by Scrrem

There is member here in VA that installed the OBX headers and exhaust on a 91 ZR-1 and loves it.....no issues with installation, looks and sounds great.
Rich

Thanks, I have heard some mixed reviews. I want to make sure I'm not loosing any hp over the factory stock system plus picking up a little more aggresive sound

would be nice. I will be putting on the cat back first then do headers the following year. Keep the comments coming and let me hear what you think if you know someone with the system.

**SteelBlueZR1** · 04-02-12, 10:30 AM

Originally Posted by abbezr1

Thanks, I have heard some mixed reviews. I want to make sure I'm not loosing any hp over the factory stock system plus picking up a little more aggresive sound

would be nice. I will be putting on the cat back first then do headers the following year. Keep the comments coming and let me hear what you think if you know someone with the system.

I too am considering the OBX exhaust after this weekends ZR1 Net Wazoo dyno pull day. My stock 1991 6k mile ZR1 pulled 321 hp with just a chip and K&N/open airbox. Right before that another member's 1991 ZR1 with chip and OBX Exhaust pulled 340 hp. Same dyno, same day, same year car, only difference was OBX. I heard the car and the exhaust looked and sounded amazing. I also think it is clear that the exhaust is picking up 10-20 hp over my stock 1991 exhaust.

The OBX exhaust seemed to strike a nice balance with its sound level vs. stock.

**catbert** · 04-02-12, 10:35 AM

Originally Posted by SteelBlueZR1

I too am considering the OBX exhaust after this weekends ZR1 Net Wazoo dyno pull day. My stock 1991 6k mile ZR1 pulled 321 hp with just a chip and K&N/open airbox. Right before that another member's 1991 ZR1 with chip and OBX Exhaust pulled 340 hp. Same dyno, same day, same year car, only difference was OBX. I heard the car and the exhaust looked and sounded amazing. I also think it is clear that the exhaust is picking up 10-20 hp over my stock 1991 exhaust.

The OBX exhaust seemed to strike a nice balance with its sound level vs. stock.

I've been adding aftermarket exhausts since......well, a loooong time. I've dyno'd most all of them ,and I've never seen anything approachinng 20 horsepower with catbacks only.

**Hib Halverson** · 04-02-12, 01:12 PM

Originally Posted by SteelBlueZR1

I too am considering the OBX exhaust after this weekends ZR1 Net Wazoo dyno pull day. My stock 1991 6k mile ZR1 pulled 321 hp with just a chip and K&N/open airbox. Right before that another member's 1991 ZR1 with chip and OBX Exhaust pulled 340 hp. Same dyno, same day, same year car, only difference was OBX. I heard the car and the exhaust looked and sounded amazing. I also think it is clear that the exhaust is picking up 10-20 hp over my stock 1991 exhaust.

The OBX exhaust seemed to strike a nice balance with its sound level vs. stock.

An exhaust on a 91...10 hp, probable.
20-hp....possible, but not likely.

Keep in mind that there was a variation engine-to-engine with LT5s. besides that, even though it was the same day and the same dyno, car-to-car differences can be huge. The temperature inside the dyno area can be an issue along with tires, lubricants, gasoline...bottom line, the comparison you make is suspect.

Now, if you tested your car with that exhaust and the conditions in the dyno area were the same, then, you'd have a valid comparison.

**SteelBlueZR1** · 04-02-12, 02:06 PM

Originally Posted by Hib Halverson

An exhaust on a 91...10 hp, probable.
20-hp....possible, but not likely.

Keep in mind that there was a variation engine-to-engine with LT5s. besides that, even though it was the same day and the same dyno, car-to-car differences can be huge. The temperature inside the dyno area can be an issue along with tires, lubricants, gasoline...bottom line, the comparison you make is suspect.

Now, if you tested your car with that exhaust and the conditions in the dyno area were the same, then, you'd have a valid comparison.

I concur, however there is an article on this website where a ZR1 c4 picks up 18 HP with just a Flowmaster exhaust and reaches +28hp from stock exhaust with custom mufflers and pipes. As you know the 90-91 exh resonator is a big restriction in the stock exhaust; I was only commenting that it was interesting that 2 91 zr1s identical except exhaust for aftermarket exhaust were20 HP apart. I stated the aftermarket exhaust was likely the reason for the difference, accounting for 10-20 HP. Here is the ZR1 c4 28+HP increase exhaust article:
Corvette Action Center Knowledgebase :: 1992 - 1996: Tech Article: Quietly Powerful: How to Build a C4 LT1/4/5 Exhaust that Gains 28 hp and...is Quiet

**Hib Halverson** · 04-02-12, 09:27 PM

Originally Posted by SteelBlueZR1

I concur, however there is an article on this website where a ZR1 c4 picks up 18 HP with just a Flowmaster exhaust and reaches +28hp from stock exhaust with custom mufflers and pipes. As you know the 90-91 exh resonator is a big restriction in the stock exhaust; I was only commenting that it was interesting that 2 91 zr1s identical except exhaust for aftermarket exhaust were20 HP apart. I stated the aftermarket exhaust was likely the reason for the difference, accounting for 10-20 HP. Here is the ZR1 c4 28+HP increase exhaust article:
Corvette Action Center Knowledgebase :: 1992 - 1996: Tech Article: Quietly Powerful: How to Build a C4 LT1/4/5 Exhaust that Gains 28 hp and...is Quiet

I'm aware of that article, perhaps I should have said: 20-hp from an off-shelf, bolt-on aftermarket exhaust is possible but not likely.

For the price of the OBX exhaust, it should performance should be in the "not likely" range.

**abbezr1** · 04-04-12, 07:39 PM

Thanks for all your input! I'm glad that someone responed that has heard the system. I have a stock system and I have only heard the stock system on the zr1. I have heard after market systems on many C4's but they have a differnt base sound to the engine than the zr1 does IMHO. I just wanted to make sure I wasnt loosing any power with the obx system and it sounds like I wouldnt loose any and might pick up a few. I know that there are some nice systems out on the market and I read on some post about some custom systems made for power but it's hard to beat the price tag on this sytem. Thank you all again

Now back to putting the passenger side header stud bolt back in.