Okay, I'm in-->New Exhaust=26hp

[Demps]

Custom made and was supposed to be a 3 inch with x-pipe and magnaflow mufflers. Looks like, after up on the dyno, a 2 1/2 in x-pipe with 3 inch on the rest. I'll be talking to them about that--couldn't see it when I picked the car up. Can't argue too much for the gains. Did extensive dyno'ing trying to document for an article in the KOTH (if it's not too redundant). Looks pretty good too with the Magnaflow mufflers.

 

[BiZ]

How does it sound?

 

[Demps]

It is LOUD. That's what I was wanting. The resonance is not TOO bad but it's there. Cats and manifolds are still in place which keeps it under control. It was putting down 384 actual hp. What a thrill!!! It's funny that the car kept increasing in output and we did 6 runs each with old exhaust and new exhaust. Only one run where the water temps were under 208F. MAT temps started over 100F and cooled quickly but the spark never got to the full 25 deg of advance (24). The car was pulling pretty good. I like the setup but the exhaust shop crooked me on the 3 inch x-pipe (they installed a 2 1/2). I have to confront them on that. Tips look good and the intallation was better than I expected. We pulled 6 consecutive runs with the stock exhaust and they all varied with 2 hp. The custom exhaust dyno's kept getting better. The first 3 showed 15 hp and 10 lb-ft. The last (12th total dyno run) showed the 26 and 20.

 

[Rob]

Did you build the system yourself or have it custom made by a company? Any pics?

 

[Demps]

Company.

 

[USA ZR1]

What size is the exhaust tubing in front of the x-pipe,Ted?
I noticed it has compression bends instead of mandrels. That hurts the flow somewhat but if it's 3" to start with,it won't be as noticeable.

 

[USA ZR1]

It looks like my sig photo is going to be way too large on this site.
It wasn't this large on another site. Any ideas how to make it smaller? Rob,feel free to delete the photo,if necessary.

 

[Rob]

Clint,

That looks awesome! However, we have size restrictions on signature photos here so that our dialup members don't suffer. If you could shrink your signature picture down, I'd appreciate it. Thanks.

From our FAQ: Please size it in pixels.. not to exceed 468 x 300 pixels and/or 30 KB in size.

 

[USA ZR1]

I'll just delete it until I can figure out how to resize it. Thanks.

 

[Rob]

Clint,

Either send me the photo or post the link again. I'll resize it and email it to you.

 

[BCZR-1]

Now that is a very mod, Ted. Gains over the entire graph. Did you have the Coplon duct in place for this dyno session? I assumed it was ok since I hadn't heard otherwise.

 

[Demps]

Brian the Coplon duct is great--but it's on my blue car. Thanks again.

Clint, I tried calling you today to talk about this exhaust. I thought it was going to be an abortion when I got the car on the rack at the dyno. Then, it just kept on making power. We were all surprised. It was supposed to be a pure 3 inch system to include X-pipe and mufflers. It ended up being a stock exhaust mounting flange (so it would bolt up) with what I think is a 2 1/2 inch X-pipe and crush bent 3 inch tubing to 3 inch mufflers. I was severely ****ed in the exhaust shop's dishonesty until it made 26 more hp and 20 more lb-ft. It's hard to argue the gain even though they flat out lied.

There is little to NO monkey business with this test. I dyno'd the car 6 times with the stock exhaust and it did not vary greater than 2 hp (339.2-340.5). When I got to the dyno shop after the mod, they were busy. I let the car cool to 176F water temp and the MAT was 89F. We did a pull and it was at 364 SAE/384 actual hp. On the runs we had a snap-on diagnostic scanner measuring all the parameters and we took coolant temp, knock, MAT, and spark adv. After the car was hot, the spark advance only went to 24 deg (25 deg cold). The exhaust runs were typically at 356 hp and 342 lb-ft. On the twelveth total pull (6th of the exhaust) the car was 208F and heated to 212F (same as the stock runs) and the power was what is posted above. Run 5 was the best stock pull and run 12 was the best hot exhaust pull.

Okay, question to the masses. Does the car trim for WOT (open vs closed loop)??? Do the open loop tables reference change in conditions? The car kept making power with each succesive pass under similar conditions (one run the car was HOT).

ted

 

[4cefed]

Are you planning on headers in the future?
Joel

Brian the Coplon duct is great--but it's on my blue car. Thanks again.

Clint, I tried calling you today to talk about this exhaust. I thought it was going to be an abortion when I got the car on the rack at the dyno. Then, it just kept on making power. We were all surprised. It was supposed to be a pure 3 inch system to include X-pipe and mufflers. It ended up being a stock exhaust mounting flange (so it would bolt up) with what I think is a 2 1/2 inch X-pipe and crush bent 3 inch tubing to 3 inch mufflers. I was severely ****ed in the exhaust shop's dishonesty until it made 26 more hp and 20 more lb-ft. It's hard to argue the gain even though they flat out lied.

There is little to NO monkey business with this test. I dyno'd the car 6 times with the stock exhaust and it did not vary greater than 2 hp (339.2-340.5). When I got to the dyno shop after the mod, they were busy. I let the car cool to 176F water temp and the MAT was 89F. We did a pull and it was at 364 SAE/384 actual hp. On the runs we had a snap-on diagnostic scanner measuring all the parameters and we took coolant temp, knock, MAT, and spark adv. After the car was hot, the spark advance only went to 24 deg (25 deg cold). The exhaust runs were typically at 356 hp and 342 lb-ft. On the twelveth total pull (6th of the exhaust) the car was 208F and heated to 212F (same as the stock runs) and the power was what is posted above. Run 5 was the best stock pull and run 12 was the best hot exhaust pull.

Okay, question to the masses. Does the car trim for WOT (open vs closed loop)??? Do the open loop tables reference change in conditions? The car kept making power with each succesive pass under similar conditions (one run the car was HOT).

ted

 

[DDSLT5]

Clint,

Either send me the photo or post the link again. I'll resize it and email it to you.

Hey Rob, I'm new here too, can i send a couple of photos to you as well for resizing?

Dwight

 

[Rob]

Hey Rob, I'm new here too, can i send a couple of photos to you as well for resizing?

Dwight

Sure. I will send you my email address.

 

[USA ZR1]

How's this one for sizing?

 

[Rob]

How's this one for sizing?

Perfect!!

 

[USA ZR1]

Outstanding! Thank you,Rob.

 

[rkreigh]

the X pipe really seems to help the big exh. with the stock displacement and engine, the 2.5 neck down probably doesn't hurt that much, but I would get it 3" all the way to see.

ted, the difference between 24 and 25 isn't bad and may be from the IAT correction being applied, the WOT values look really stout and if the car doesn't show any knock, you are getting good clean pulls.

fyi,

I think the cats make more of a difference in restriction than the 2.5 "choke point" so until you go to headers, it probably won't make any difference in power.

those are really impressive gains from an exh change. from what I read, you didn't do any chip recal right??? since the factory cal is usually a bit rich you are probably running about right on the AF ratio now.

ted is a lucky man, two pristine 95s. I remember a certain 95 I drove back from Ted's place, I will miss that car (as does ted) but I couldn't keep 3 ZR1s forever, and now the vettes are paid for which helps keep the peace. cya.

 

[YESZREE]

Brian the Coplon duct is great--but it's on my blue car. Thanks again.

It was supposed to be a pure 3 inch system to include X-pipe and mufflers. It ended up being a stock exhaust mounting flange (so it would bolt up) with what I think is a 2 1/2 inch X-pipe and crush bent 3 inch tubing to 3 inch mufflers. I was severely ****ed in the exhaust shop's dishonesty until it made 26 more hp and 20 more lb-ft. It's hard to argue the gain even though they flat out lied.

If this is a Magnaflow x-pipe and it looks like that's what it is, it shows on their website that the x-pipe IS 2.5" with a 3" core. That is the center passthru IS 3".