Shooting for 9's - Stick car/ECS blower only
 

Well, as some have you have seen recently, I am getting down the home stretch of bringing my M7 ECS car into the 9s. Today, I think I found the last piece of the puzzle, which may help all of us. First thing first, if you have a NON-Npp exhaust, throw it in the garbage. Here are some pics why:


https://cimg6.ibsrv.net/gimg/www.cor...3937ca59b8.jpg


Stock outlet


https://cimg7.ibsrv.net/gimg/www.cor...0d19ec023d.jpg


Inside of muffler from inlet, goes in 6" and stops. Perforation is the only relief for airflow.

Also, on both NPP and non NPP, exhaust inlet is 2.25 id after afm butterfly. I recently purchased a NPP and I know a lot of people are running this exhaust with good results, but I can almost gaurentee that there are significant gains after measuring and examining these as well.

I decided today that I will not be running an axle back at all, and running turn downs instead before the rear axle. I also trimmed the neck down area at the end of the ARH x pipe and attached the turn downs here. Now the exhaust is true 3" until the very end. The new setup is very loud, but the power is SIGNIFICANT. I will be back on dougs dyno shortly for back to back results. After driving the car today I can say that a real 3" exhaust for this car for anyone with a blower would be a worthwhile investment. B&B seems to be the only one on the market at this point.

Keep in mind, I ran 10.3 at 137mph on the non-npp mufflers, and they were screaming for dear life. It also made 740whp before they were removed. Stock cam. ECS kit with 2200sl upgrade. Stay tuned.

https://cimg0.ibsrv.net/gimg/www.cor...4b7abddb64.jpg


Full 3" turn downs

In for numbers, both dyno and track...fwiw I picked up at both when I turndowned for what with my measly 500rwhp, don't know that it'll be worth .3 though Godspeed

:iagree: This is sadly the case - it's a nasty re-use of the smaller NPP valve assembly welded onto the pipe. Kind of an OEM hack-job.

Attachment 48367615

It really is a shame, especially because the same exact exhaust is used on the z06. The c6 z06 exhaust was 3" from the factory, and got slightly smaller right at the muffler, a MUCH better design than these.

I'll be rooting for you! If you can get a stick car into the 9's that'll be impressive. No offense to anyone, but a point and shoot car such as an auto is not nearly as impressive as someone manually shifting gears and achieving those numbers. Good luck!!! I'll be watching for your results.

I'm surprised it bottled down that much, but I could hear it screaming on the dyno as if a cat was clogged.

Looking forward to your results Steve.

do you have a mod list?

Sure, mods are as follows:

ECS blower kit with 2200SL upgrade
3.75 pulley
2" arh headers/ x pipe
Alky control kit with one nozzle
Lash cap on stock pump
93/109 mix (100 octane average)
265/40/18 mickey et street radials on tsw interlargos wheels

Thats it! Stock motor, trans, clutch, rear. non z-51 3LT package.

That's insane that you're getting those kind of ETs with those mods. 9's are my goal as well, I'm currently putting in a cam and I have an ECS 1500 blower on order.

I wonder if the larger head unit over the 1500 is making the big difference in power for those ETs.

How much power are you putting down? How much boost?

Few questions for you as i admire what your car has done so far. I have the npp, if i get rid of it and do the 3" turn downs do you think i will get a decent gain? Do you still have the stock clutch? How hard are you leaving on it? Do you change the fluid frequently? mine makes 710/653 right now and would like to start aiming for low 10s/high 9s as well. When i was at the track second pass i launched at 4k and slipped it a little and the clutch was having none of that! slipped 1st and second! im on 20 inch wheels with 315 r888s so im scared to even put 18s on it. Should i drop it faster? at 3k rpm i had no issues.

I will have better info next week when i get back on the dyno about the turndowns. Keep in mind i am coming from a non-npp exhaust which is much worse than an NPP. Doug at ECS has tons of data so we will know right away how much of a gain these are really making over the stock over the axle pipes/mufflers. As fast as your wheels and tires, you need a drag radial with some sidewall to get your 60 foots down. I recommend an 18" wheel as you can generally get better tire sizing with more sidewall, and it is the smallest that will fit over the stock rear spindle. Mickey Thompson, M&H and hoosier are the best options, and they all vary in streetability. I will tell you this.. and call me crazy... but I would not be surprised if the power jumps from 740whp to over 800 whp getting rid of the non-npp mufflers judging by how bad they really look in terms of flow and how the car feels after removing them. To answer your question about the clutch, yes it is still stock and holding up fine.

Are you still using the stock shifter? I know this seems like a silly question, but, I'm having shifter issues post supercharger install. I would like to know if you're having or have ever had shifting issues under a heavy load?

If it picks up 60 you may gain .3, in for results...good luck, Chris

In for the 9 sec Slip!!:thumbs:

Rooting for you to hit 9's :rock:

Fast M7 vette builds are just so much more exciting.

Good luck and subbing for results :thumbs:

i have never in all my years seen 60 rwhp from dropping mufflers
do i think it will pick up some yes but no where near that!!
also you are gonna need a little more tire than the 265

but keep up the hard work and keep us posted

Good luck and have been watching your build and rooting for your 9 second slip from the beginning. :flag:


The $4,550 additional in dealer cost for the Z51 is ridiculous.
Headers with turn-downs are a much better option.

What's the best price on a 3" cat back for comparison?



Sad to see you give up the man pedal that you had in your 427ci C5 for that weak A8. :(
You went from one of the best C5 1/4 mile shifters, to a slushbox owner. :lol:

I know it sounds like a crazy claim, but if you could have heard the stock exhaust at this level, or have witnessed what i looked at when i cut them off, you may agree. I have had many cars, and the stock non-npp mufflers are by far the worst I have ever seen. I can not believe the car even made the power that it did out of them. As far as the tire, they are still holding, and i am using them at 19-20 psi. They still have a lot more in them with a harder launch and lower pressures, not to mention doing a drag alignment in the rear.

I guarantee you were outflowing the crap (flow-wise) stock non-NPP system. As an alternative to dumps, I've been looking into the new (and I'm not suggesting anything here) Borla Z06 systems that omit the AFM completely to remain straight back to the muffler.

I do hope that more exhaust systems/companies will follow suit and do this, even though it's not exactly for the C7 crowd, but rather for the C7Z. Guess there's always hope for the Akrapovic.

I fabbed a set of downturned dumps similar to yours a little while back (just for fun, honestly, and to test if I'd like cutouts again) and ran for about 20 minutes before my brain wanted to explode. Dumps are less-than-fun unless you're on the track. Then anything goes. ;)

I have to agree 100%. The dumps are VERY LOUD, but i can tell the car is much faster. Over the weekend I am going to work on fabbing something up that still dumps under the car but quieter. There is actually a lot of space on either side of the transmission in front of the axle, so I am going to see what kind of mufflers i can fit. I am going to also come up with something for the stock exhaust outlet hole (some sort of diffuser or grille plate) to clean it up a little bit. I feel like this would be the perfect setup once completed. Saves about 45lbs too!