Shouldn't my car be quicker?

[LS1Formulation]

I've got a 2013 SS M6, and I just took it to the strip after a significant number of mods, but the ET is not where I feel it should be. Last year, with just a Roto-Fab cold air intake, I ran between a 13.08 and 13.25 on average, trapping about 109-111. Anywhere from a 1.97 to a 2.10 60'. I just finished installing a BTR Stage IV LS3 cam, 1 7/8" long tubes, under drive balancer and a set of 3.91 gears, and a 160° thermostat, along with a mail order tune from PCM of NC, which I know isn't optimal but I needed my car running and couldn't get a dyno tune. Took it out to the track the other day, similar weather conditions to my best runs last year, and it ran a 12.64@112.25 and a 12.65@112.70, with 1.95 60's both runs. Yes, I do know how to drive a manual, I have 3 cars and none are autos. The car just hooks and goes, absolutely zero tire spin even with a 5000 clutch dump, which seems suspicious, given that everyone I've spoken with seems to have traction problems even stock. Could my mail order tune be THAT far off? I feel like this thing should be in the bottom 12s with my mods. I will add that it was 4070 lbs. with me in it, but I still believe it should have gained more. I'd really be curious to see what other M6 cars have ran with this cam.

[joshnmn]

Does seem like something is off. I'm also thinking low 12, high 11 numbers. I don't have any experience in a M6 but from what I've seen, guys are feathering the clutch, not dumping it at 5k. The guys at PCm are good, maybe theres something else going on.

[LS1Formulation]

I'm not just sidestepping the clutch, but I wouldn't call it feathering, either. The motor just pulls down and it squats and goes. On the street, it feels strong as hell, but it's not translating to the track. I will say, ever since I bought the car, it has felt stronger when leaving all the nannies on. Holding down the TCS button for 7 seconds and turning everything off seems to make the car feel less aggressive. Maybe I'm just feeling something that isn't there. I don't know, I just am not happy with my gains.

[frankwjr]

your 60 is sub optimal...what suspension and tires are you using? I launch at 5k+ also but get 1.6x 60 ft.

post some time slips and other will chime in...

[IKILLEDSUPERMAN_ZL1]

I've was told when I started racing that every tenth you shaved off your 60 is worth 2 tenths off on the big end. That's been pretty accurate in my experience.

[JMI]

If I were you, I would start datalogging the car to confirm everything is OK before you beat on it too much.Send datalog to tuner or pay a visit to a good local LS tuning/dyno shop and have it checked out.

Tune might be off for your setup, or might be something wrong mechanically, fuel pump might not be 100% as an example.

Tune can be spot on for one car and be off on another with the same mods.

[acammer]

So, we're missing some key information to really understand your ETs - what is the density altitude? A 12.6 at 8,000' of DA might not be that bad, at sea level it would be very suspicious. Post up your best slip, and lets dissect it a little bit. My gut reaction is that it looks pretty slow, I would expect a health cam/gear setup to gain nearly a second over what it was capable with as a bolt on car, but that can vary some.

I suspect there are some issues with your mail order tune as well. Your launch sounds suspiciously like it's probably riding the RPM vs. MPH limiter - from the factory these cars have a table that limits the RPM to 5000rpm until the vehicle is moving over 10mph. This can make launching a stick car on a good track with a good tire tricky - you need more RPM than that unless you're coming off a two-step. I have a good quick video about this on my YouTube that might apply here.



I also have a lengthy video on launch techniques for these heavy M6 cars. You might find this valuable as well.

[13_SS_RS]

Weather(DA) and the particular track you are at play a part as well. I've raced at two different dragstrips for years. One dragstrip was consistently faster than the other. The track I usually went because it was close to home would usually be a .5 second slower. When your not racing try to pay attention to what other cars are running to get an idea also. I've also found talking to other 5th gen owners in the staging lanes about what's done to their cars helps get an idea of where your car is at.

[LS1Formulation]

I do know weather and DA play a part, but unfortunately, I don't know what the DA was that day. It was 80°, and I know that can slow a car down, but I ran some of my best times late July last year in hotter temps than that. I will say, as to what acammer posted, that problem with the launch table sounds exactly like what my car does when I launch. Is the fix to have that table adjusted or simply disabled, and to install a two step? If so, I'll do that and report back. After I get a truetrac installed first... My spider gears decided to shatter on me.

Here are my runs:

1.9593 - 60'
5.4211 - 330'
8.2586 - 1/8
88.72 mph
10.6395 - 1000'
102.18 mph
12.6521 - 1/4
112.70 mph

1.9576 - 60'
5.4077 - 330'
8.2377 - 1/8
88.92 mph
10.6215 - 1000'
101.65 mph
12.6434 - 1/4
112.25 mph

[Modernmusclecar]

Your trap speed seems
very low. I was 12.6 @112 with fbos and drag radial. My 1.9 sixty still was a bit of. Went with a heads and cam package. Ran 12.1 @118 with a budget convertor still 1.9 sixty. Not sure why the mph is low.

[LS1Formulation]

I agree... How did I run 111 with just a CAI, but I add a cam, LT's,gears, underdrive pulleys and a tune and only pick up 1mph?

[acammer]

Originally Posted by LS1Formulation

I do know weather and DA play a part, but unfortunately, I don't know what the DA was that day. It was 80°, and I know that can slow a car down, but I ran some of my best times late July last year in hotter temps than that. I will say, as to what acammer posted, that problem with the launch table sounds exactly like what my car does when I launch. Is the fix to have that table adjusted or simply disabled, and to install a two step? If so, I'll do that and report back. After I get a truetrac installed first... My spider gears decided to shatter on me.

Here are my runs:

1.9593 - 60'
5.4211 - 330'
8.2586 - 1/8
88.72 mph
10.6395 - 1000'
102.18 mph
12.6521 - 1/4
112.70 mph

1.9576 - 60'
5.4077 - 330'
8.2377 - 1/8
88.92 mph
10.6215 - 1000'
101.65 mph
12.6434 - 1/4
112.25 mph

It's easy to fix, you just set the wheelspeed vs rpm limiter table to whatever your actual limiter is in the 0 and 9.9mph boxes.

The trap speed looks low, but that's because it's a slug in the front half. It's picking up 24mph in the back half, which isn't stellar, but isn't bad either. When the 60' comes down, the mph will go up.

[demonspeed]

Couple things:
1) dragtimes.com you can get DA from virtually any track and from virtually any day
2) With virtually identical mods (BTR4, Rotofab, Kooks w/cats through NPP; made 450 on Mustang dyno) went 12.5@115 which I was very disappointed in. I did, however, have misfire codes which turned out to be from bronze trunnions being worn and rockers flopping around.

I have been racing stick cars for two decades, but that was the first I ever had the 5th Gen to the track. acammer’s video on launching is superb, and I will personally be trying his advice my next track outing.

[acammer]

One more thing I don't think we covered.... what rear gear is in the car? The factory 3.45 is really not ideal for these cars from a drag race perspective. A 4.10 is absolutely not too much gear for these cars, and really helps wake them up for drag racing. The shorter gearing helps get the car off the line easier and more quickly, and places the RPM in a much better place at the finish light - better average power the whole length of the run means faster. 3.45 to 4.10s was worth two tenths on my car when it was bolt ons, with garbage $100 tires. Cammed, on a good tire, it would be worth even more.