Unable to 60ft - Suggestions?
07-17-2016, 07:41 PM
#1
Burning Brakes
Thread Starter
Unable to 60ft - Suggestions?
Man,
I have not been able to get a decent 60ft on my C6Z. Running 18X10.5 Replica wheels and Hoosier 335/30/18s @ 17.5 pounds. I have played around with the launching RPMs from 3000-5000 slipping the clutch, and more aggressive clutch engagement.
If I get a little and I mean little aggressive it will spin and hop. If lower it, it will bog big time. Have not been able to find the right approach.
My old car was heavier, and I could consistent 60ft in the 1.39-1.43 every day launching on a 175 shot. True, suspension was dedicated and a full slick.
I think that the aluminum flywheel may be hurting my launches. May be not enough inertia to get me out the hole and having to up the RPMs and making me spin.
What are you guys with AL flywheel launching at? Do I need to get really aggressive with the clutch slip?
Doing a mild burn-out around 2-3 seconds, shallow staging.
On Friday night, my best 60ft was 2.11 bogging it, which sucks!
My other 2 passes where identical 2.18s spinning with mild hop.
My ETs sucked, with the best of 11.1x (2.18 60) and my MPH was 136.3xMPH.
Density altitude was 2841 so she has more MPH in her and should be able to get into the sub-10.5. Car is full weight, 599rw, stock suspension, and the tire combo listed above...93 fuel.
Here is GoPro perspective of the launch. Listen to the engine RPMs during launch and the 60fts. Is the burnout lenght enough?
Tell me what you see/hear!
Suggestions?
I have not been able to get a decent 60ft on my C6Z. Running 18X10.5 Replica wheels and Hoosier 335/30/18s @ 17.5 pounds. I have played around with the launching RPMs from 3000-5000 slipping the clutch, and more aggressive clutch engagement.
If I get a little and I mean little aggressive it will spin and hop. If lower it, it will bog big time. Have not been able to find the right approach.
My old car was heavier, and I could consistent 60ft in the 1.39-1.43 every day launching on a 175 shot. True, suspension was dedicated and a full slick.
I think that the aluminum flywheel may be hurting my launches. May be not enough inertia to get me out the hole and having to up the RPMs and making me spin.
What are you guys with AL flywheel launching at? Do I need to get really aggressive with the clutch slip?
Doing a mild burn-out around 2-3 seconds, shallow staging.
On Friday night, my best 60ft was 2.11 bogging it, which sucks!
My other 2 passes where identical 2.18s spinning with mild hop.
My ETs sucked, with the best of 11.1x (2.18 60) and my MPH was 136.3xMPH.
Density altitude was 2841 so she has more MPH in her and should be able to get into the sub-10.5. Car is full weight, 599rw, stock suspension, and the tire combo listed above...93 fuel.
Here is GoPro perspective of the launch. Listen to the engine RPMs during launch and the 60fts. Is the burnout lenght enough?
Tell me what you see/hear!
Suggestions?
Last edited by Da Z06; 07-18-2016 at 08:56 AM.
07-18-2016, 04:57 PM
#2
Supporting Vendor
Man,
I have not been able to get a decent 60ft on my C6Z. Running 18X10.5 Replica wheels and Hoosier 335/30/18s @ 17.5 pounds. I have played around with the launching RPMs from 3000-5000 slipping the clutch, and more aggressive clutch engagement.
If I get a little and I mean little aggressive it will spin and hop. If lower it, it will bog big time. Have not been able to find the right approach.
My old car was heavier, and I could consistent 60ft in the 1.39-1.43 every day launching on a 175 shot. True, suspension was dedicated and a full slick.
I think that the aluminum flywheel may be hurting my launches. May be not enough inertia to get me out the hole and having to up the RPMs and making me spin.
What are you guys with AL flywheel launching at? Do I need to get really aggressive with the clutch slip?
Doing a mild burn-out around 2-3 seconds, shallow staging.
On Friday night, my best 60ft was 2.11 bogging it, which sucks!
My other 2 passes where identical 2.18s spinning with mild hop.
My ETs sucked, with the best of 11.1x (2.18 60) and my MPH was 136.3xMPH.
Density altitude was 2841 so she has more MPH in her and should be able to get into the sub-10.5. Car is full weight, 599rw, stock suspension, and the tire combo listed above...93 fuel.
Here is GoPro perspective of the launch. Listen to the engine RPMs during launch and the 60fts. Is the burnout lenght enough?
Tell me what you see/hear!
https://youtu.be/-3TGINOv2A0
Suggestions?
I have not been able to get a decent 60ft on my C6Z. Running 18X10.5 Replica wheels and Hoosier 335/30/18s @ 17.5 pounds. I have played around with the launching RPMs from 3000-5000 slipping the clutch, and more aggressive clutch engagement.
If I get a little and I mean little aggressive it will spin and hop. If lower it, it will bog big time. Have not been able to find the right approach.
My old car was heavier, and I could consistent 60ft in the 1.39-1.43 every day launching on a 175 shot. True, suspension was dedicated and a full slick.
I think that the aluminum flywheel may be hurting my launches. May be not enough inertia to get me out the hole and having to up the RPMs and making me spin.
What are you guys with AL flywheel launching at? Do I need to get really aggressive with the clutch slip?
Doing a mild burn-out around 2-3 seconds, shallow staging.
On Friday night, my best 60ft was 2.11 bogging it, which sucks!
My other 2 passes where identical 2.18s spinning with mild hop.
My ETs sucked, with the best of 11.1x (2.18 60) and my MPH was 136.3xMPH.
Density altitude was 2841 so she has more MPH in her and should be able to get into the sub-10.5. Car is full weight, 599rw, stock suspension, and the tire combo listed above...93 fuel.
Here is GoPro perspective of the launch. Listen to the engine RPMs during launch and the 60fts. Is the burnout lenght enough?
Tell me what you see/hear!
https://youtu.be/-3TGINOv2A0
Suggestions?
It's been my experience that Hoosiers like between 18.5 and 18.75 psi and this has worked well using 275/40/17, 315/35/17, 335/35/17 and 315/30/18 sizes. I know the difference between what you're running is minimal compared to mine, but I've seen my 60ft times increase quite a bit if I end up having to sit in the staging lanes for too long after I've already gotten strapped in and can't be bothered to get out and check the pressures again.
Also, the tire pressure needs to be measured before every pass. I've known people who would measure it once when they first get to the track but it can change quite a bit depending on the ambient air temperature so it's crucial to keep an eye on it.
Your burnouts do seem too short. I've found that 5-6 seconds is optimal and I also make sure to accelerate coming out of the water box but before I get staged. I scan all of my passes using HP Tuners and will routinely hit 130MPH during my burnout.
How old are your tires? I just posted a used set for sale that still had lots of life left in them, but seemed to have lost the ability to maintain traction for the high 1.3 60ft times I can get if the track is properly prepped.
The following users liked this post:
Da Z06 (07-28-2016)
07-19-2016, 01:15 AM
#3
Race Director
Christopher had some good thoughts. I agree with you that your aluminum flywheel is making it hard for you to launch. Drag racers with manual trannies normally need a heavier flywheel to launch, road racers a lighter one because they are already moving and need quick acceleration.
07-19-2016, 07:43 AM
#4
Advanced
Christopher had some good thoughts. I agree with you that your aluminum flywheel is making it hard for you to launch. Drag racers with manual trannies normally need a heavier flywheel to launch, road racers a lighter one because they are already moving and need quick acceleration.
07-19-2016, 01:21 PM
#5
To prevent your bog, either your tires have to spin or your clutch needs to slip until your car is traveling fast enough for engine speed to sync up with vehicle speed. Unlike bias slicks, radial tires don't typically work effectively when they spin much at all, so mastering clutch slip is where you need to concentrate your efforts.
Ideally, the slip time of the clutch during launch needs to be extended out to about .7 seconds or so. That will give your car enough time to accelerate to the point that your engine won't bog when the clutch locks up, and the tires will stay stuck to the track without any wheelhop. Your goal should be to launch the car in such a way that you are basically controlling WOT engine rpm with the clutch pedal. Start by practicing low 3000rpm launches. Slam the throttle WOT while releasing the clutch pedal in a controlled manner, with just enough slippage to prevent rpm from dipping below launch rpm. After you've mastered 3000rpm launches, move on up in 500rpm increments. You will get quicker launches from up around your engine's torque peak and beyond, but working your way up from 3000rpm will minimize wear/tear on the drivetrain as you experiment with your technique. With enough practice you can get pretty good results from your left foot.
There are other ways to extend the amount of time that your clutch slips, such as an in-line restrictor orifice between the clutch master / hyd tob, or an adjustable hydraulic cylinder installed on the clutch pedal to control it's release. Many racers start out using the restrictor setups offered by Magnus or McLeod, but find their reaction times suffer because the in-line restriction delays the entire release cycle of the clutch pedal. R/T with these units can be minimized by "pre-loading" the drivetrain slightly when staging, basically minimizing tob travel to the point the clutch grabs. Even doing this though, reaction time will still suffer a bit.
The alternate method of installing an adjustable cylinder on the clutch pedal has the added tuning option of adjusting the available "freeplay" of the cylinder, basically allowing the pedal to travel un-restricted for a tunable distance before the delay action becomes effective. Reaction times are not affected. There are a lot of fast MT drag cars using this method now on diaphragm PP's, but you won't find many discussing it openly. With tire spin taken out of the picture, rpm data becomes much more useful.
Ideally, the slip time of the clutch during launch needs to be extended out to about .7 seconds or so. That will give your car enough time to accelerate to the point that your engine won't bog when the clutch locks up, and the tires will stay stuck to the track without any wheelhop. Your goal should be to launch the car in such a way that you are basically controlling WOT engine rpm with the clutch pedal. Start by practicing low 3000rpm launches. Slam the throttle WOT while releasing the clutch pedal in a controlled manner, with just enough slippage to prevent rpm from dipping below launch rpm. After you've mastered 3000rpm launches, move on up in 500rpm increments. You will get quicker launches from up around your engine's torque peak and beyond, but working your way up from 3000rpm will minimize wear/tear on the drivetrain as you experiment with your technique. With enough practice you can get pretty good results from your left foot.
There are other ways to extend the amount of time that your clutch slips, such as an in-line restrictor orifice between the clutch master / hyd tob, or an adjustable hydraulic cylinder installed on the clutch pedal to control it's release. Many racers start out using the restrictor setups offered by Magnus or McLeod, but find their reaction times suffer because the in-line restriction delays the entire release cycle of the clutch pedal. R/T with these units can be minimized by "pre-loading" the drivetrain slightly when staging, basically minimizing tob travel to the point the clutch grabs. Even doing this though, reaction time will still suffer a bit.
The alternate method of installing an adjustable cylinder on the clutch pedal has the added tuning option of adjusting the available "freeplay" of the cylinder, basically allowing the pedal to travel un-restricted for a tunable distance before the delay action becomes effective. Reaction times are not affected. There are a lot of fast MT drag cars using this method now on diaphragm PP's, but you won't find many discussing it openly. With tire spin taken out of the picture, rpm data becomes much more useful.
The following users liked this post:
Da Z06 (07-28-2016)
07-22-2016, 03:47 PM
#6
Le Mans Master
I commented in your other thread, but in this video I see that your car crept a bit before you launched. Like I said there, a longer burnout would be better and then you just have to get the clutch release in synch with your right foot going to the floor...It's not easy, especially if your clutch is stiff with a low, small engagement point.
Practice, practice...And forget the tree (Reaction Time) while you're learning the best technique for your launch!
Try to get to a rental whenever you can until you perfect your launch!
I'd also say do NOT throw any more HP at the car until you get the launch. More HP=even HARDER to launch.
Ron
Practice, practice...And forget the tree (Reaction Time) while you're learning the best technique for your launch!
Try to get to a rental whenever you can until you perfect your launch!
I'd also say do NOT throw any more HP at the car until you get the launch. More HP=even HARDER to launch.
Ron
07-28-2016, 09:10 AM
#7
Burning Brakes
Thread Starter
To prevent your bog, either your tires have to spin or your clutch needs to slip until your car is traveling fast enough for engine speed to sync up with vehicle speed. Unlike bias slicks, radial tires don't typically work effectively when they spin much at all, so mastering clutch slip is where you need to concentrate your efforts.
Ideally, the slip time of the clutch during launch needs to be extended out to about .7 seconds or so. That will give your car enough time to accelerate to the point that your engine won't bog when the clutch locks up, and the tires will stay stuck to the track without any wheelhop. Your goal should be to launch the car in such a way that you are basically controlling WOT engine rpm with the clutch pedal. Start by practicing low 3000rpm launches. Slam the throttle WOT while releasing the clutch pedal in a controlled manner, with just enough slippage to prevent rpm from dipping below launch rpm. After you've mastered 3000rpm launches, move on up in 500rpm increments. You will get quicker launches from up around your engine's torque peak and beyond, but working your way up from 3000rpm will minimize wear/tear on the drivetrain as you experiment with your technique. With enough practice you can get pretty good results from your left foot.
There are other ways to extend the amount of time that your clutch slips, such as an in-line restrictor orifice between the clutch master / hyd tob, or an adjustable hydraulic cylinder installed on the clutch pedal to control it's release. Many racers start out using the restrictor setups offered by Magnus or McLeod, but find their reaction times suffer because the in-line restriction delays the entire release cycle of the clutch pedal. R/T with these units can be minimized by "pre-loading" the drivetrain slightly when staging, basically minimizing tob travel to the point the clutch grabs. Even doing this though, reaction time will still suffer a bit.
The alternate method of installing an adjustable cylinder on the clutch pedal has the added tuning option of adjusting the available "freeplay" of the cylinder, basically allowing the pedal to travel un-restricted for a tunable distance before the delay action becomes effective. Reaction times are not affected. There are a lot of fast MT drag cars using this method now on diaphragm PP's, but you won't find many discussing it openly. With tire spin taken out of the picture, rpm data becomes much more useful.
Ideally, the slip time of the clutch during launch needs to be extended out to about .7 seconds or so. That will give your car enough time to accelerate to the point that your engine won't bog when the clutch locks up, and the tires will stay stuck to the track without any wheelhop. Your goal should be to launch the car in such a way that you are basically controlling WOT engine rpm with the clutch pedal. Start by practicing low 3000rpm launches. Slam the throttle WOT while releasing the clutch pedal in a controlled manner, with just enough slippage to prevent rpm from dipping below launch rpm. After you've mastered 3000rpm launches, move on up in 500rpm increments. You will get quicker launches from up around your engine's torque peak and beyond, but working your way up from 3000rpm will minimize wear/tear on the drivetrain as you experiment with your technique. With enough practice you can get pretty good results from your left foot.
There are other ways to extend the amount of time that your clutch slips, such as an in-line restrictor orifice between the clutch master / hyd tob, or an adjustable hydraulic cylinder installed on the clutch pedal to control it's release. Many racers start out using the restrictor setups offered by Magnus or McLeod, but find their reaction times suffer because the in-line restriction delays the entire release cycle of the clutch pedal. R/T with these units can be minimized by "pre-loading" the drivetrain slightly when staging, basically minimizing tob travel to the point the clutch grabs. Even doing this though, reaction time will still suffer a bit.
The alternate method of installing an adjustable cylinder on the clutch pedal has the added tuning option of adjusting the available "freeplay" of the cylinder, basically allowing the pedal to travel un-restricted for a tunable distance before the delay action becomes effective. Reaction times are not affected. There are a lot of fast MT drag cars using this method now on diaphragm PP's, but you won't find many discussing it openly. With tire spin taken out of the picture, rpm data becomes much more useful.
Ill play and get aggressive with the clutch slip, that is the only way given the tire I'm running and avoid breaking suspension and/or differential parts.
Really appreciate the comments.
07-30-2016, 05:32 PM
#8
Drifting
You also need to try to be consistent with your launch RPM either using a 2 step or (what I use) the Raptor dual stage shift light with launch light. I went from having my launch RPM +/- 1500 RPM to +/- 100 RPM using it.
08-28-2016, 11:53 PM
#11
Banned Scam/Spammer
You 100% were not dragging out the clutch. I dont want to sound like a dihk but i have only had six speed cars and can launch pretty well. When I started i had 2,1-2.2 Now on a stock clutch and 649 rwhp I am doing a consistent 1,64 1.63. Its all practice practice practice. I def can hear your rpms drop way to low when you launch. All I can say is practice and go out and have fun. Its the fun of six speeds. It took me a while to finally figure out my cars.
Can you post your time slip? I would like to see whats going on, I am just curious. I am no expert, and I dont know anything, just would like to see what you are doing. I will post my slips also.
Can you post your time slip? I would like to see whats going on, I am just curious. I am no expert, and I dont know anything, just would like to see what you are doing. I will post my slips also.
Last edited by yellowzron; 08-28-2016 at 11:54 PM.