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I might head out tomorrow to my local 1/8 mile, which would be actually my 1st time doing the 1/8 mile on the C5. I want some pointers on prep and launching based on my tires and mods (tire PSI? engine launch RPM? clutch release timing/technique? shifting RPM?...etc.), and finally what can I expect with a decent launch.
My power/TQ: 397RWHP, 400RWTQ
Mods: Stock 853 heads with dual valve springs and Ti retainers, Mild Cam .585/.585/228/230 112LSA, NA bolt ons: LS6 intake, TSP 1-3/4 offroad headers and Xpipe. Stock clutch and drivetrain. Rears: 325/30/19 Michelin Pilot Sport Cup 2 , Fronts: 275/35/18 Michelin Pilot Super Sports. Stock M6/T56 with 3:42 Final Drive. Rev limiter set at 7k, but power starts to taper down quickly after 6600.
My power graph for reference:
Last edited by turabo87; Mar 21, 2019 at 10:28 AM.
Small burnout, street tires are not worth it really. Start tire pressure @ 25 psi. Stock drivetrain and clutch so I would go easy on the launch. Maybe try slipping clutch at 2000 rpm and see where that gets you. Nothing too crazy tho. If it spins, low tires a little. It takes a lot of practice to get a good launch. If your under 2.0 60 foot on street tires your doing pretty well. I'd say with your power if you can get a low 8 for your first time, your doing good. Trap maybe 90mph. Let us know how it goes and post slips.
Small burnout, street tires are not worth it really. Start tire pressure @ 25 psi. Stock drivetrain and clutch so I would go easy on the launch. Maybe try slipping clutch at 2000 rpm and see where that gets you. Nothing too crazy tho. If it spins, low tires a little. It takes a lot of practice to get a good launch. If your under 2.0 60 foot on street tires your doing pretty well. I'd say with your power if you can get a low 8 for your first time, your doing good. Trap maybe 90mph. Let us know how it goes and post slips.
Sounds like great starting points. You really think 2k launch RPMs though? I was thinking it would bog at 2k. I know it depends on track prep and tires but I was thinking closer to 2.5k or 3k.
I just said 2k to save the drivetrain honestly. 🙂. You can launch where ever you like but I would start there. Do not dump the clutch, slippage is needed. Takes a little practice.
First pass terrible. I’m the 9.03. Raced a CTSV auto on drag radials.
Second pass. I’m the 8.67, raced the same auto CTSV with drag radials.
You’re tips were great and you were right about times. I ended up launching at about 2.5k both times but I really wanted to launch closer to 2k, I just over-feathered it from the excitement I guess. My reaction time sucks, I know now I just need to time/expect that fourth light instead of waiting to see it. First pass was 9.03, second pass was 8.67. Wheel slip on both, but much less on second pass (I slipped more and RPMs were lower on launch). First pass I was at about 28psi, second pass 25 psi.
Will aim for low 8s next time.
Last edited by turabo87; Mar 23, 2019 at 01:26 AM.
Times look good for your first time. 60' needs work, but they always need work. Haha. That's where seat time will help. Maybe try 22psi next time. Reaction time doesn't really matter unless your bracket racing or something like that. But a tip I use to cut a good light is go on the last yellow. When the last yellow lights go, by the time it gets to your brain and then to your foot is about the time the green will light. Good job.
Times look good for your first time. 60' needs work, but they always need work. Haha. That's where seat time will help. Maybe try 22psi next time. Reaction time doesn't really matter unless your bracket racing or something like that. But a tip I use to cut a good light is go on the last yellow. When the last yellow lights go, by the time it gets to your brain and then to your foot is about the time the green will light. Good job.
I can tell you know your stuff. You got excellent tips. I will make sure to go on the last yellow. So now that you saw my times, let's talk hypothetically. What do you think I could do as far as the best 60ft and 1/8 with my current street tires (325/30/19), versus what do you think I might do with drag radials? Also, do you know how that 1/8 mile translates to a 1/4 mile time? I can see why this stuff is addicting now.
There are a few different calculators on the internet that can help with 1/8 to 1/4. I use Wallace racing for all of my car related equations. You will find out the more you go that 60' means everything for a good ET. That's why practice comes in handy. As far as your current tires, there could be a 2.0 to be had but street tires are very inconsistent. So you would really have to get lucky. Drag radials are better and slicks are best. Budget matters also. I myself run drag radials because I don't want to change tires at the track. I drive there, race, drive home. If you want to continue, I would suggest at a minimum a trans brace. They some solid mounts. And start to budget for a rear end. You can beef it up. I did mine last summer. C6Z shafts, clutches and springs. Or, if your not a DIY'er, give RKT a call.
Sounds like a slippery money slope. I think I'll stay with my street tire setup and just work on the driver mod to get to the 2.0 60ft, and work on keeping my ego down and under control when I lose lol. I didn't know I would need a trans brace with drag radials at my torque and power level. Anyway, I have to be careful and avoid risking my drivetrain too much, because the C5 is my one and only daily now since I sold my truck.
Last edited by turabo87; Mar 26, 2019 at 08:19 AM.
Beefing up the drivetrain can definetly get expensive. That's what I put my money towards last year. I very much enjoy drag so I had to. But just keep practicing and have fun with it.
Nice work! Keep working that 60' and you'll see improvements. 1/8 mile is all in the 60'.
Example below (as you were looking for a comparison): My bolt on car (~350whp) cut a 1.939 on street tires (best is a 1.931), 1/8 was a 8.262@87.33 on a 83 degree day (DA of 3200+).
Street tires and consistent launching (Ranger method is awesome) and you'll get sub 2.0 60's. That should equate to a better 1/8 and 1/4 than the above. You are on the way! I bet in the 1/4 you are running 12's already.
What are you launching at for RPM? With my twin disc on street tires the sweet spot was around 2200 after a quick "burnout"/tire scrub. That was on a 275 series autocross tire (RE71R). Clutch up as gas goes down at the same time.
Last edited by niterydr; Mar 26, 2019 at 08:54 AM.
Nice work! Keep working that 60' and you'll see improvements. 1/8 mile is all in the 60'.
Example below (as you were looking for a comparison): My bolt on car (~350whp) cut a 1.939 on street tires (best is a 1.931), 1/8 was a 8.262@87.33 on a 83 degree day (DA of 3200+).
Street tires and consistent launching (Ranger method is awesome) and you'll get sub 2.0 60's. That should equate to a better 1/8 and 1/4 than the above. You are on the way! I bet in the 1/4 you are running 12's already.
What are you launching at for RPM? With my twin disc on street tires the sweet spot was around 2200 after a quick "burnout"/tire scrub. That was on a 275 series autocross tire (RE71R). Clutch up as gas goes down at the same time.
Awesome times! It’s hard to say where exactly I launched because I overfeather it and then I was slowly releasing throttle while the staging lights were on to lower it to where I wanted which was 2k. I think I launched somewhere between 2200-2400, but I think between 2k and 2.2k might be my sweet spot. I had wheelspin on that launch.
Awesome times! It’s hard to say where exactly I launched because I overfeather it and then I was slowly releasing throttle while the staging lights were on to lower it to where I wanted which was 2k. I think I launched somewhere between 2200-2400, but I think between 2k and 2.2k might be my sweet spot. I had wheelspin on that launch.
A little wheelspin is okay, for me I've found my best 60's on street tires are where the nose "stays up". If it comes down then to much wheel spin or bog, both kill the short times.
Get some junk wheels and drag radials, dont worry about when you leave it doesnt matter.
Even if you left without spinning you stillhave to watch for wheelsspin in other gears why bother at that point?
Unless youre dumping the clutch you should be ok.
Lowering pressire too much on st tires can reduce your contact patch
You dont need to drive it to break it but why go if (some will recommend) you need to baby it?
Well, 2nd time on the 1/8 mile track and I seem to be improving but I feel I have so much more to go. This was my best run of 3 that night. I'm in the left lane. I still beat the CTSV that had drag radials because of my reaction time, which felt awesome. My launch was at about 1500-1600RPM. Bogged slightly but at least it gripped and pulled with grip all the way through 1st gear. I'd like to get a 2.0 60ft on these street tires, but the track prep sucks at this 1/8 mile and I'm not sure if my tires can go much lower than a 2.2 60ft. I've seen on Youtube ridiculous times of 7.6-7.8 on 350WHP C5 Z06 on drag radials. I find this incredible and makes me want to go get some proper drag radials.
Pardon the atrocious video quality; I need to get a proper dash cam. Here's the 8.559 run:
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1/8 mile expectations and recommendations?
