M7 drag racers with the stock clutch ...
10-04-2017, 06:02 PM
#1
Le Mans Master
Thread Starter
M7 drag racers with the stock clutch ...
may want to consider a small drag radial on an 18" rim.
I'll start by saying that I have no seat time in a c7 on the strip but have been thinking about a few possible combos for the average guy/gal who visits the strip in his or her street car.
Also I was at the strip recently and watch some new z06 owners struggle getting down the track with their cars which made me think about this topic.
Here's what I came up with and why.
For most all m7 setups I'd recommend bias ply tires with skinnies but I get that there are very few options so let's stick with a radial.
I just cant recommend a street tire for an m7 on any drag strip, especially a run flat, so we're now down to a drag radial. And I know stock tires grip pretty well and may produce a decent 60' on a rare occasion but it's just not the right way to go to run any type of respectable time.
I've also seen a lot of carnage caused by street tires on the drag strip on the launch and even on the 1-2. Most of the time this can be avoided with a radial and the proper launch technique. Wheel hop still can occur with the radial but it is much less likely with proper technique and the stock clutch tends to slip more so than a stout aftermarket clutch which can help.
So we have wheel hop to contend with and on the opposite end of the spectrum we have to avoid burning through the clutch. Not an easy task. You want the clutch to slip a little, the tires to spin a little, but neither too much and avoid wheel hop.
It's difficult to find that happy medium plus, you want to be able to launch high enough so the motor does bog down to too low of an rpm where the motor doesn't want to be in order to obtain any sort of decent 60' time.
Assuming we can only fit an 18" radial, there's not too many choices.
Knowing all of the issues above, I found a player that I think would work well with some practice which might be far from the popular choice.
The tire is a 245 40 18 Hoosier drag radial.
It has a lot of what I'm looking for with these particular setups.
First off, it's a trusted brand that I've always had success with. Plus Hoosier drag radials are lighter than most due to their unique construction. This tire happens to be 22 lbs of rotating mass. That's a good number.
Secondly, It's narrow. Yes narrow! Narrow tires tend to wheel hop less in general with these cars. Plus narrow is lighter and easier to spin which we want with the stock clutch. Furthermore, narrow is less rolling resistance which means faster provided traction which I believe it has enough of.
Another advantage of it's small size is that you need a smaller rim for it to fit on which is lighter as well.
I'd be comfortable with a 7-9.5 inch rim to wrap these around with 8-9.5 my preference.
A 9.5 rim will be a stretch but the added benefit is slightly more gearing which helps as well as slightly less strain on the clutch.
Maybe a c5 coupe rear rim or c7 front rim would work to keep it simple.
Now the key with any tire or setup for that matter is seat time. It's going to take practice, and lots of it. The stock clutch has it's limitations and won't hold over a certain rpm and riding it too much. You want some slip, some wheel spin, while minimizing bog.
Another tip is to always do a quick burnout. That doesn't necessarily mean small but quick. The less time you heat up any clutch the better.
Pumping the clutch after the burnout and before staging can benefit as well.
Tire pressure will vary among the different setups. If the clutch is straining you can alter your technique and raise the pressure. I wouldn't be mad at 25+ lbs of pressure with some setups to get it all to work. The higher the pressure the better the et provided traction.
Could this tire work. I really believe so and feel it may just be the best choice for an M7 with a stock clutch. I would expect it would work at Z06 power levels as well. The clutch being the limiting factor. I can also see this wheel/tire combo working with an aftermarket clutch provided not too much hp and some sound launch technique.
Keep in mind, we are talking 1.6x's here after some substantial seat time. Maybe a little better or worse depending on how much time you want to put in. This would be a huge improvement over the 60' times I've been seeing on good tracks with stock clutches and tires.
Another modification that would help these setups is gears. I'd go with 4.10s to wake these cars up on the street. That would also help with the launch and put less strain on the stock clutch. A win/win all around for me especially in a stock-ish grand sport that need some encouragement.
So, IMO, bigger isn't always better. I hope this can provide some food for thought when selecting a tire for the occasional strip goer.
I don't have a handle on the specifics of the launch in a manual c7/stock clutch but I have an idea what it would take.
Making a rear wheel drive optimized road race car with a clutch perform on the drag strip is a challenge and takes some out of the box thinking based on experience.
Maybe I'll get a chance to test this theory or perhaps someone else will try but it's something I wanted to share with other fellow corvette racing enthusiasts. That's my story.
I'll start by saying that I have no seat time in a c7 on the strip but have been thinking about a few possible combos for the average guy/gal who visits the strip in his or her street car.
Also I was at the strip recently and watch some new z06 owners struggle getting down the track with their cars which made me think about this topic.
Here's what I came up with and why.
For most all m7 setups I'd recommend bias ply tires with skinnies but I get that there are very few options so let's stick with a radial.
I just cant recommend a street tire for an m7 on any drag strip, especially a run flat, so we're now down to a drag radial. And I know stock tires grip pretty well and may produce a decent 60' on a rare occasion but it's just not the right way to go to run any type of respectable time.
I've also seen a lot of carnage caused by street tires on the drag strip on the launch and even on the 1-2. Most of the time this can be avoided with a radial and the proper launch technique. Wheel hop still can occur with the radial but it is much less likely with proper technique and the stock clutch tends to slip more so than a stout aftermarket clutch which can help.
So we have wheel hop to contend with and on the opposite end of the spectrum we have to avoid burning through the clutch. Not an easy task. You want the clutch to slip a little, the tires to spin a little, but neither too much and avoid wheel hop.
It's difficult to find that happy medium plus, you want to be able to launch high enough so the motor does bog down to too low of an rpm where the motor doesn't want to be in order to obtain any sort of decent 60' time.
Assuming we can only fit an 18" radial, there's not too many choices.
Knowing all of the issues above, I found a player that I think would work well with some practice which might be far from the popular choice.
The tire is a 245 40 18 Hoosier drag radial.
It has a lot of what I'm looking for with these particular setups.
First off, it's a trusted brand that I've always had success with. Plus Hoosier drag radials are lighter than most due to their unique construction. This tire happens to be 22 lbs of rotating mass. That's a good number.
Secondly, It's narrow. Yes narrow! Narrow tires tend to wheel hop less in general with these cars. Plus narrow is lighter and easier to spin which we want with the stock clutch. Furthermore, narrow is less rolling resistance which means faster provided traction which I believe it has enough of.
Another advantage of it's small size is that you need a smaller rim for it to fit on which is lighter as well.
I'd be comfortable with a 7-9.5 inch rim to wrap these around with 8-9.5 my preference.
A 9.5 rim will be a stretch but the added benefit is slightly more gearing which helps as well as slightly less strain on the clutch.
Maybe a c5 coupe rear rim or c7 front rim would work to keep it simple.
Now the key with any tire or setup for that matter is seat time. It's going to take practice, and lots of it. The stock clutch has it's limitations and won't hold over a certain rpm and riding it too much. You want some slip, some wheel spin, while minimizing bog.
Another tip is to always do a quick burnout. That doesn't necessarily mean small but quick. The less time you heat up any clutch the better.
Pumping the clutch after the burnout and before staging can benefit as well.
Tire pressure will vary among the different setups. If the clutch is straining you can alter your technique and raise the pressure. I wouldn't be mad at 25+ lbs of pressure with some setups to get it all to work. The higher the pressure the better the et provided traction.
Could this tire work. I really believe so and feel it may just be the best choice for an M7 with a stock clutch. I would expect it would work at Z06 power levels as well. The clutch being the limiting factor. I can also see this wheel/tire combo working with an aftermarket clutch provided not too much hp and some sound launch technique.
Keep in mind, we are talking 1.6x's here after some substantial seat time. Maybe a little better or worse depending on how much time you want to put in. This would be a huge improvement over the 60' times I've been seeing on good tracks with stock clutches and tires.
Another modification that would help these setups is gears. I'd go with 4.10s to wake these cars up on the street. That would also help with the launch and put less strain on the stock clutch. A win/win all around for me especially in a stock-ish grand sport that need some encouragement.
So, IMO, bigger isn't always better. I hope this can provide some food for thought when selecting a tire for the occasional strip goer.
I don't have a handle on the specifics of the launch in a manual c7/stock clutch but I have an idea what it would take.
Making a rear wheel drive optimized road race car with a clutch perform on the drag strip is a challenge and takes some out of the box thinking based on experience.
Maybe I'll get a chance to test this theory or perhaps someone else will try but it's something I wanted to share with other fellow corvette racing enthusiasts. That's my story.
10-05-2017, 08:06 AM
#2
Melting Slicks
Member Since: Aug 2016
Location: MOUNTAIN HOME Arkansas
Posts: 2,687
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I don't get your post. You say you have no seat time in a C7 but then offer a ton of "advice". I gather from reading between the lines you must have "drag strip" experience but why advise us about a car you HAVEN'T raced. Did you sleep in a Holiday Inn Express last nite?
10-05-2017, 10:26 AM
#3
Le Mans Master
Thread Starter
I don't get your post. You say you have no seat time in a C7 but then offer a ton of "advice". I gather from reading between the lines you must have "drag strip" experience but why advise us about a car you HAVEN'T raced. Did you sleep in a Holiday Inn Express last nite?
Any thoughts on the content rather than the motive? You seem to be interested in the title perhaps. Thanks
10-06-2017, 09:19 AM
#4
Le Mans Master
Thread Starter
These rims may work. Would have to check
clearences on car but they are cheap yet likely heavy.
That's price is for a set of 4.
Last edited by robz; 10-06-2017 at 09:24 AM.
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10-06-2017, 11:55 AM
#8
E-Ray, 3LZ, ZER, LIFT
Member Since: Sep 2007
Location: NE South Carolina
Posts: 29,484
Received 9,619 Likes
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6,625 Posts
Since the OP is just "bench racing" I'll jump in! I would never buy and automatic Vette BUT if drag racing a Z06 would not consider anything else!Even with drag slicks a Z06 will be traction limited. Hard to beat an automatic to manage. Slipping the clutch worked as a teenager in my first car, a '41 opera coupe that I stuffed in an Olds engine. That was to keep those skinner tires of the day from just "burning rubber." But if slipping the clutch on a Z06 best be prepared to replace it and perhaps some dif parts!
Last edited by JerryU; 10-06-2017 at 11:57 AM.
10-06-2017, 12:00 PM
#9
Advanced
For a lot less than the cost of tires, clutch and whatever might break you could just buy a race car if you want to simply go in a straight line. Prepped tracks break cars every day, slap on some drag radials or slicks and its just a matter of time before things start getting expensive. There was a 9 second G-body streetcar for sale at the track last week for less than $10,000. It's not pretty but its quick....
Peace,
Don
Peace,
Don
Last edited by Champ203; 10-06-2017 at 12:01 PM.
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JerryU (10-06-2017)
10-06-2017, 04:06 PM
#10
Le Mans Master
Thread Starter
A lot of votes for auto, makes sense, it's easier especially in stock form on the drag strip. With practice, the m7 could be fast and consistent. I guess the key is to develop the right technique for consistency and to keep parts from breaking.
Let's just assume you have an m7 and don't plan on trading it in for an auto. It's fun take passes at the strip and learn how to launch the car, but you need a decent tire. That's why I think that drag radial will work especially for newer racers. And I don't consider this just bench racing. I want someone who's into the 1/4 mile to give it a try. I noticed that no one on the list or in the c7 threads has even considered a tire like this. I wish I was around to push it when the 1st c7 m7 stingrays were testing things out. But it's never too late, just need a new wave of hot shots that want to go fast with a stick. I'd imagine that the GS is going to run slower than the stingray. We may need to have them make a separate category on the fast list. Soon enough.
Let's just assume you have an m7 and don't plan on trading it in for an auto. It's fun take passes at the strip and learn how to launch the car, but you need a decent tire. That's why I think that drag radial will work especially for newer racers. And I don't consider this just bench racing. I want someone who's into the 1/4 mile to give it a try. I noticed that no one on the list or in the c7 threads has even considered a tire like this. I wish I was around to push it when the 1st c7 m7 stingrays were testing things out. But it's never too late, just need a new wave of hot shots that want to go fast with a stick. I'd imagine that the GS is going to run slower than the stingray. We may need to have them make a separate category on the fast list. Soon enough.
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Gxpz06 (10-23-2017)
10-06-2017, 05:40 PM
#13
Le Mans Master
Thread Starter
Retired.
I do have a c7 GS though.
I still think that a lot more in the m7 than has been proven.
Just read someone went 10.3 stock with a drag a drag pack in a c7Z which most people previously were saying couldn't happen.
It's tough especially with the more sophisticated cars these days. They're obviously not intended for the strip but it's fun to see then perform in an arena there not made for like in any sport.
The m7 definitely needs an drag radial though to show any kind of consistency.
I do have a c7 GS though.
I still think that a lot more in the m7 than has been proven.
Just read someone went 10.3 stock with a drag a drag pack in a c7Z which most people previously were saying couldn't happen.
It's tough especially with the more sophisticated cars these days. They're obviously not intended for the strip but it's fun to see then perform in an arena there not made for like in any sport.
The m7 definitely needs an drag radial though to show any kind of consistency.
11-12-2017, 06:33 PM
#18
Le Mans Master
Thread Starter
So I was able to actually test my theory of using a small drag radial on a c7 with the stock clutch.
I haven't been to a drag strip since 2014 and as mentioned above I have no experience with a c7. However, I felt that my experience in the c5 platform has provided me with enough knowledge to understand what it takes to launch a manual c7 successfully.
I had not planned to track my new c7 GS but after reading so many threads of people searching for the widest drag radial possible I felt I might have test out some theories so I could provide concrete evidence that a narrow drag radial might in fact be the best option for many c7 racers with a reasonable amount of HP.
Rewind to about 1 month ago, I was watching 2 new c7Z06 (M7) owners taking passes at the strip. The were both struggling on the launch. I was a little surprised to see that both had glazed their clutches with stock cup tires. This made me more convinced that a drag radial is just going to make this problem worse.
So eventually I caved in a bought a Hoosier drag radial and mounted in on my buddy's (Gary2004Z06) c6Z front rims and they cleared on the back of my GS despite all efforts not wanting to beat on this car.
I was able to sneak out today last minute to give them a try. I used the hour drive down to the track to get a feel for this car that I hadn't shifted over 5500rpms yet.
Test: Does a narrow drag radial, that most wouldn't even consider, have enough traction to provide a good enough launch and 60' with the stock clutch?
So here are the result. I say my theory is plausible based on only 2 passes.
2017 GS (bolt ons) ~430whp Mustang dyno
RW: 3535lbs
18" Hoosier (245 40 18) drag radials with Forgestars 18" skinnies
Atco, NJ test-n-tune
Launch 1: (first launch in years)
~4800 rpms
22.5 psi cold
touring mode
1.74 60'
perception: Some bog and stumble. A little too long on clutch and slightly too quick on throttle. Slight glaze of the clutch. Track prep was good.
On this shakedown pass the car ran 11.51 shifting around 6200/6300 if anyone cares.
Adjustments made and flushed in some fresh fluid via the "Ranger method". Fluid didn't look bad.
Launch 2:
4500rpms
25 psi warm
Sport mode
1.53 60'
perception: car felt good with a slight stumble/hop, released clutch quicker, and quick throttle squeeze. Slight glaze of the clutch.
Aborted pass due to hitting limiter on the 1-2
So there's the real world data. It's obvious to me that the small radial works and there is still more left in the 60'.
Conclusion: A narrow 245 drag radial with 25psi can hook well enough to propel a 3500lb c7 to a respectable 60'.
A wider tire would put more strain on the clutch and the car in general and slow the car down IMO.
My goal is to provide knowledge through my experience to corvette drag racers so they can utilize the same parts and techniques I have without wasting valuable time and money.
I haven't been to a drag strip since 2014 and as mentioned above I have no experience with a c7. However, I felt that my experience in the c5 platform has provided me with enough knowledge to understand what it takes to launch a manual c7 successfully.
I had not planned to track my new c7 GS but after reading so many threads of people searching for the widest drag radial possible I felt I might have test out some theories so I could provide concrete evidence that a narrow drag radial might in fact be the best option for many c7 racers with a reasonable amount of HP.
Rewind to about 1 month ago, I was watching 2 new c7Z06 (M7) owners taking passes at the strip. The were both struggling on the launch. I was a little surprised to see that both had glazed their clutches with stock cup tires. This made me more convinced that a drag radial is just going to make this problem worse.
So eventually I caved in a bought a Hoosier drag radial and mounted in on my buddy's (Gary2004Z06) c6Z front rims and they cleared on the back of my GS despite all efforts not wanting to beat on this car.
I was able to sneak out today last minute to give them a try. I used the hour drive down to the track to get a feel for this car that I hadn't shifted over 5500rpms yet.
Test: Does a narrow drag radial, that most wouldn't even consider, have enough traction to provide a good enough launch and 60' with the stock clutch?
So here are the result. I say my theory is plausible based on only 2 passes.
2017 GS (bolt ons) ~430whp Mustang dyno
RW: 3535lbs
18" Hoosier (245 40 18) drag radials with Forgestars 18" skinnies
Atco, NJ test-n-tune
Launch 1: (first launch in years)
~4800 rpms
22.5 psi cold
touring mode
1.74 60'
perception: Some bog and stumble. A little too long on clutch and slightly too quick on throttle. Slight glaze of the clutch. Track prep was good.
On this shakedown pass the car ran 11.51 shifting around 6200/6300 if anyone cares.
Adjustments made and flushed in some fresh fluid via the "Ranger method". Fluid didn't look bad.
Launch 2:
4500rpms
25 psi warm
Sport mode
1.53 60'
perception: car felt good with a slight stumble/hop, released clutch quicker, and quick throttle squeeze. Slight glaze of the clutch.
Aborted pass due to hitting limiter on the 1-2
So there's the real world data. It's obvious to me that the small radial works and there is still more left in the 60'.
Conclusion: A narrow 245 drag radial with 25psi can hook well enough to propel a 3500lb c7 to a respectable 60'.
A wider tire would put more strain on the clutch and the car in general and slow the car down IMO.
My goal is to provide knowledge through my experience to corvette drag racers so they can utilize the same parts and techniques I have without wasting valuable time and money.
Last edited by robz; 11-12-2017 at 06:35 PM.
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larrywalk (11-13-2017)
11-13-2017, 12:00 PM
#20
Le Mans Master
There are a LOT of ways to go slower and make the 1/4 more "challenging". They're things to avoid.
Look at the bright side, I've never met a man at a dragstrip with more excuses than a manual driver. Every one I ever roast misses a shift supposedly, but the auto guys just kick pebbles when they lose because there's no excuse.
Look at the bright side, I've never met a man at a dragstrip with more excuses than a manual driver. Every one I ever roast misses a shift supposedly, but the auto guys just kick pebbles when they lose because there's no excuse.
Last edited by davepl; 11-13-2017 at 12:02 PM.