seevi

I put a pair of 2008 ZO6 mufflers on my 2007 LS2. I was going to put the entire system on, but I didn't want to mess with the H pipe by the transmission. Also, the ZO6 NPP mufflers have a 2.5" input. So I cut the mufflers off the pipes and welded them on the 2.5" OEM pipes.

I went to Irwindale Raceway and the difference in an 1/8th mile was .019 seconds. I have not had the car re-tuned, but it is apparent that it needs to be tuned again.

455HOGT37

Trap MPH is the better indicator for horsepower. What was your before and after MPH?

seevi

I have a 2007 coupe with automatic and was going to convert the entire system with a 2008 ZO6 exhaust system. After looking at the O2 sensors and the misalignment of the "H" pipe near the transmission, I opted to just replace the mufflers with the NPP mufflers. The 2.5" straight threw and NPP's will hold almost 4X the engine displacement and flows okay. I cut the 3" pipes off the NPP mufflers at the 2.5" inlet and welded on the 2.5" pipes from the OEM mufflers. I picked up .019 on the 1/8th mile with the new mufflers open.

This is not a substitute for headers, and there is no obvious visual changes when the car needs to be smoged.

HOXXOH

.019? Are you sure you didn't mean .19?

Most guys aren't that consistant on back to back passes, let alone different days.

Although .19 is more than would be expected by a 6 HP increase.

NORTY

I thought the LS7 exhaust would be incompatible with the LS2 because of the exhaust port shape. I think the ZR1 system would be a better fit on the standard LS3, however.

AgDriller

Well I finished installing the LS7 manifolds and 3" H-pipe on my '05 just yesterday (i already has 2-1/2" GHL mufflers). It was a very straight forward install. You do NOT need O2 extensions but you do need to unwrap the tape for the front sensor back to the firewall end of the fuel rails. The back O2 sensor is no problem. On the stock manifolds the front sensor is in the middle of the exhaust manifolds. On the LS7 version, the front sensor is just in front of the cat on the cat pipe. Like I said, if you unwrap the tape from the front sensor, it will reach the 'pig tail' on the sensor it self.

If you have questions on the install, PM me. There is quite a bit of info on the forum about removing the stock system and installing headers. There is some out there on the install of the LS7 system, too.

As far as dyno before and after. I should have taken up a collection. I put a Vararam on a couple of weeks ago and could tell some difference. With the LS7 exhaust, it really revs without feeling restricted at higher RPM's. The sound is awesome without it sounding quite as 'raspy' from the engine compartment.

I will do a tune - hopefully on a dyno. That would give an 'after' number. It seems there is quite a bit of stock data in the +/-350 RWHP range. Overall, I would highly recommend it if emission testing is a concern and/or you don't have big power in your future.

455HOGT37

They are compatable, but clearly not optimum. The round ports of the LS7 headers likely creates some reversion at the port exit, but hopefully, the better shape (compared to the cast iron LS3 units) gives you a net gain.

Keith N

California emission testing influenced my decision to go with the Z06 full exhaust along with a more reasonable price and some excellent hp gains.

Vegas Panton

Two Vegas Vettes club members have had this conversion. Both had LS 2 engines. They both included 3 inch aftermarket Z06 mufflers, one Corsa and one Borla. The post Z06 LS7 conversion increase were +25 RWHP (386 RWHP with 6 speed) in one case and +30 RWHP (373 RWHP A6) in the other. Pre and post Dyno runs were on the same Dynojet Dyno and tuned by the same tuner. In aother words the cars were tuned to the same level (timing, A/F ratios, etc.) before and after the conversions. Another club member is going to do the same thing to his wife's 2008 LS3. I suspect the LS3 should respond as well as the LS2's because it has the same basic exhaust system unless you have the NPP mufflers.

STLBLUES

08 6spd
Z manifolds, cats , Hpipe and Z mufflers. Full Z system

Same track similar weather conditions. 4 weeks apart.

Best before 2.028 60' / 12.79 @ 112.01mph / 8.39@ 87.66

Best after Z system only (no tune - exhaust sytem change only)
2.015 60' / 12.50 @ 115.03mph / 8.218@ 90.18

Backed by several 12.8's and then 12.5's

Someone do the math. Whats 3mph in HP? I would say at least 15 rwhp was gained.

Anyone doing this in the near future should check out my polished Z manifolds in the for sale section.

455HOGT37

3 MPH is significant! What is the weight of the car? There should be a HP calculator on the web somewhere to convert this...

C6DuffMan

112MPH
Your HP computed from your vehicle ET is 249.59 rear wheel HP and 277.32 flywheel HP.
Your HP computed from your vehicle MPH is 317.47 rear wheel HP and 352.74 flywheel HP.

115MPH
Your HP computed from your vehicle ET is 267.37 rear wheel HP and 297.08 flywheel HP.
Your HP computed from your vehicle MPH is 343.67 rear wheel HP and 381.85 flywheel HP.

HOXXOH

Got a URL for the calculator?

STLBLUES

http://www.stangnet.com/calcs/hpcalc.htm

Curb with driver
3385

371 @ 112
401 @ 115

Might not be very accurate but 371+ is common for a stock ls3 6spd.

The in car gain felt just like a pair headers on a c5/c6 to me. I have installed or helped on 7 sets so I know about what to expect from headers. The LS7 manifolds are a good cheap mod that alot of people are missing out on.

adam205348

Not to bash your times or your claims or anything but I have a 08 A6 and I have only run it at a 1/8th miles track but it consitantly runs 8.0 @ 90mph on the craptastic runflats and similar 60ft times. Mine is a showroom bone stock LS3 with F55 suspension and the factory NPP exhaust. So without the NPP exhaust I can understand somewhat little slower time but I would think with a 6spd manual vs 6spd automatic you actually get more power to the ground stock than I do.

455HOGT37

The ultimate times are not important, but taking out the variation is. This was the same car and driver, and the average (flywheel/RW) HP gain was about 22 using the data in post #32, and 30 HP from post #34. That's pretty good for an easy and cheap mod. I think it also shows that the 6 HP gain that GM claims for the NPP alone is not as significant as the Z manifolds/cats and mid pipes.

AgDriller

It also should be noted that his better times are WITHOUT a tune. I hope to tune mine this weekend if I have time. I'll post numbers afterwords.

STLBLUES

My times seem slow to me also but they were the best I could do with each set up. Regardless of the time I just wanted to show the comparison. My times will get better when I get off my lazy but and bolt on the Procharger thats sitting on my shelf. Thats why I skipped the tune, its not finished yet. I am very happy with the results for the price compared to 1000+ for headers.

MrMagic

Just got this completed. Absolutely love it. I was really concerned because some were saying you would lose Torque and the "Bernoulli" Principle application. Well I did it with a systematic data approach and I gained 20 RWHP and 31 ft-lbs of torque. Attached is the details and the data

schpenxel

Thanks for putting that together. Very impressive and I don't think it can be beat for the price!