Drag Racing Tech - Launch Data for an NA 346 M6 Camaro with Bias-Ply ET Streets

Beginning drag racers frequently post questions about launching an M6 f-body. I have looked at data from approximately 200 runs attempting to learn how sixty-time varies with tire pressure and launch rpm. Some of you might be interested in my charts. The most obvious conclusion you'll probably draw is that serious racers are somewhat more consistent than I am. Nevertheless, here they are:

Mine would 60 ft in the 1.9x's and above at any of those tire pressures you posted lol. Mine likes 11 psi cold and 12 psi hot up to 13 psi. Anything much above that and it spins like i am on ice.

My car likes a 5000 rpm launch or thats where it stays at while the car gets up to speed.

I have the lower control arms in the lowest hole, hits the tires hard. qa1 double adj set to 8 compression 12 rebound.

Gets me a high 1.5x 60ft 90 percent of the time. Want to try different control arm settings and see if i can get the car to 60 ft better.

Mine would 60 ft in the 1.9x's and above at any of those tire pressures you posted lol. Mine likes 11 psi cold and 12 psi hot up to 13 psi. Anything much above that and it spins like i am on ice.

My car likes a 5000 rpm launch or thats where it stays at while the car gets up to speed.

I have the lower control arms in the lowest hole, hits the tires hard. qa1 double adj set to 8 compression 12 rebound.

Gets me a high 1.5x 60ft 90 percent of the time. Want to try different control arm settings and see if i can get the car to 60 ft better.

Sounds a lot like my Formula. i usually ran around 13psi hot, 5k launches. Track I run at is not exactly known for its stellar prep. LCA's in lower hole, afco's 14 compression and 11 rebound (18 ways) This is one of the last times I had the car to the track

http://www.fquick.com/images/vehicles/full/35673365017.jpg (http://www.fquick.com/garages/viewgallery.php?action=viewimg&id=365017)

Very good visual tool. I would love more variables such as D/A, Track Pavement Temp, ET and MPH. Definitly get very crazy.

What race weight was the car and power?

You guys have zeroed in on reasons why my data may appear unusual and confusing. Probably the biggest uncontrolled variable is track condition. All runs were at Sears Point in Sonoma, CA which is a world-class facility but track temperatures varied widely. Some runs were on cold evenings and others were on hot afternoons. On any given day my results were more consistent than they appear in these charts. Unfortunately, I don't have tire or track temperature data.

The reason that tire pressures between eighteen and twenty psi produced my best results is that I deliberately avoid slipping the clutch. Something must slip at launch and I prefer spinning the tires. I know that slipping the clutch (or a slipper type clutch) could have significantly improved my sixty times but I have always been willing to sacrifice a tenth or two to extend clutch life. I love my Spec 4 and I hate lying on my back in my driveway.

Real racers will test multi different tires and different setting to find what works for the car so I would not worry bout actual PSI as much as that is what worked for that car, the data back it up more or less.

What race weight was the car and power?The data includes only motor runs (nitrous launches are quite different) at approximately 425 rwhp (Mustang dyno). Race weight varied from 3350 to 3250 pounds. Rear gears were 4.10 for some runs but 4.33 for most.

Sounds a lot like my Formula. i usually ran around 13psi hot, 5k launches. Track I run at is not exactly known for its stellar prep. LCA's in lower hole, afco's 14 compression and 11 rebound (18 ways) This is one of the last times I had the car to the track

http://www.fquick.com/images/vehicles/full/35673365017.jpg (http://www.fquick.com/garages/viewgallery.php?action=viewimg&id=365017)

I would figure with the amount of power you have you could get betters 60ft's. Looks like there is a good bit of et to be had if you did. The thing is i don't know that for sure tho, I always figure if i added more power to mine i could drop them a some. With the weight and power i am at i think i have my 60fts about maxed out.

If yours drops rpm hard(bogs on the launch) then you should be able to gain 60ft by fixing that. I started running the gto trans with the 2.97 1st gear and it kept my rpms way up compared to the 2.66 in the f-body t56. I can say it was bogging down to 3000 rpm then working its way back up. That was keeping it out of the power band and having an effect on my 60ft's. With the 2.97 i can put the rpm's just about anywhere i want. I am not saying go buy that trans to fix it because there could be other ways of doing so and the 2.97 1st might not even do anything for you.

I am running 4.11's and 26x11.50x15 et street bias ply with tubes now and rim screws. So glad i got the tubes.

I see alot of t56 cars get stuck around these 60ft's and want to try and figure out whats happening.

You guys have zeroed in on reasons why my data may appear unusual and confusing. Probably the biggest uncontrolled variable is track condition. All runs were at Sears Point in Sonoma, CA which is a world-class facility but track temperatures varied widely. Some runs were on cold evenings and others were on hot afternoons. On any given day my results were more consistent than they appear in these charts. Unfortunately, I don't have tire or track temperature data.

The reason that tire pressures between eighteen and twenty psi produced my best results is that I deliberately avoid slipping the clutch. Something must slip at launch and I prefer spinning the tires. I know that slipping the clutch (or a slipper type clutch) could have significantly improved my sixty times but I have always been willing to sacrifice a tenth or two to extend clutch life. I love my Spec 4 and I hate lying on my back in my driveway.

I don't slip my clutch either, its drop and go and let wheel speed get me up to speed. What hole do you have yours lca's in and do you have adjustable rear shocks? If so what do you set them at?

My 60fts got way more consistent and low with the da rear shocks. I was recording what the rear end was doing on the launch and i could see that it was bouncing the left rear tire. I tightened up the rebound so it would not do that anymore and thats when the car started to get more consistent 60fts that were lower. The way i got mine setup the car hits the tires really hard and tries to raise the rear of the car up taking weight off the rear and was bouncing the left rear at first.

What hole do you have yours lca's in and do you have adjustable rear shocks?I have rod-end LCAs in the stock mount points. I have non-adjustable Bilstien rear shocks. I have a cheapo 1-inch diameter rear swaybar. I do have single-adjustable QA1 fronts. I have a Moser 12-bolt with a Truetrac. More or less stock rear suspension has always worked very well for me. The car always launches straight, sometimes lifting the left front wheel two inches or so and the right a bit less.

BTW, I like the video in your sig even though you shift a lot quicker than I can.

I have rod-end LCAs in the stock mount points. I have non-adjustable Bilstien rear shocks. I have a cheapo 1-inch diameter rear swaybar. I do have single-adjustable QA1 fronts. I have a Moser 12-bolt with a Truetrac. More or less stock rear suspension has always worked very well for me. The car always launches straight, sometimes lifting the left front wheel two inches or so and the right a bit less.

BTW, I like the video in your sig even though you shift a lot quicker than I can.

Where you have the lower control arms at must be one reason why your able to run alot of air pressure in your tires. I realized i needed rear shocks when my mom and dad rode with me in my car in st louis and the right rear tires was touching the wheel well lol. They were way more weaker than i ever thought. Amazingly we have never been able to see the front tires come off the ground in my car. They get to right at the point they want to lift and stay there.

Thanks man, that was in commerce, Ga last year. Believe it or not it would shift faster to 3rd and 4th if the hydraulics worked a little better. I had the clutch releasing just enough so it would not move the car sitting still with the pedal pushed in.

Figured out that posed a problem. The clutch would not realease as much from 2 to 3rd then even worse from 3rd to 4th because of the heat i think. You could see it on the data log at the track how long it was taking to shift. You could feel it having trouble going to the next gear. Having to adjust the clutch pedal out even further and hoping it will help out.

I would figure with the amount of power you have you could get betters 60ft's. Looks like there is a good bit of et to be had if you did. The thing is i don't know that for sure tho, I always figure if i added more power to mine i could drop them a some. With the weight and power i am at i think i have my 60fts about maxed out.

If yours drops rpm hard(bogs on the launch) then you should be able to gain 60ft by fixing that. I started running the gto trans with the 2.97 1st gear and it kept my rpms way up compared to the 2.66 in the f-body t56. I can say it was bogging down to 3000 rpm then working its way back up. That was keeping it out of the power band and having an effect on my 60ft's. With the 2.97 i can put the rpm's just about anywhere i want. I am not saying go buy that trans to fix it because there could be other ways of doing so and the 2.97 1st might not even do anything for you.

I am running 4.11's and 26x11.50x15 et street bias ply with tubes now and rim screws. So glad i got the tubes.

I see alot of t56 cars get stuck around these 60ft's and want to try and figure out whats happening.


The power is there, I was using the Mcleod rxt twin disk and the billet steel flywheel. The car just spun like crazy. Most nights were TnT nights cluttered with regular radial tired FWD cars and zero prep, It was mostly for fun. ET's could have improved with a better driver too LOL. The car was pretty heavy at 3650 ish without driver, it still had full interior, a/c, 6 pt mild steel cage, stock k member etc. ET could also be improved with better driving skills, I'm really terrible in all honesty. You can seen plenty of videos on youtube, user name Juiced91z and a few other videos with the same name in the title if you search. It was fbody t-56, 4.11's and 28" Hoosiers. The car made 665rwhp 760 ftlbs on nitrous, but was a slip n slide down the track.

Where you have the lower control arms at must be one reason why your able to run alot of air pressure in your tires. I realized i needed rear shocks when my mom and dad rode with me in my car in st louis and the right rear tires was touching the wheel well lol. They were way more weaker than i ever thought. Amazingly we have never been able to see the front tires come off the ground in my car. They get to right at the point they want to lift and stay there.

Thanks man, that was in commerce, Ga last year. Believe it or not it would shift faster to 3rd and 4th if the hydraulics worked a little better. I had the clutch releasing just enough so it would not move the car sitting still with the pedal pushed in.

Figured out that posed a problem. The clutch would not realease as much from 2 to 3rd then even worse from 3rd to 4th because of the heat i think. You could see it on the data log at the track how long it was taking to shift. You could feel it having trouble going to the next gear. Having to adjust the clutch pedal out even further and hoping it will help out.

I never saw much more than a little daylight under the tires of my car. In some of the side/rear go pro videos you can see the car raise up and the tires not spin (off the ground) for a very split second and then get right back on the ground. The suspension needed much more attention to get it dialed in. But I always had fun with it running mid-high 10's

The power is there, I was using the Mcleod rxt twin disk and the billet steel flywheel. The car just spun like crazy. Most nights were TnT nights cluttered with regular radial tired FWD cars and zero prep, It was mostly for fun. ET's could have improved with a better driver too LOL. The car was pretty heavy at 3650 ish without driver, it still had full interior, a/c, 6 pt mild steel cage, stock k member etc. ET could also be improved with better driving skills, I'm really terrible in all honesty. You can seen plenty of videos on youtube, user name Juiced91z and a few other videos with the same name in the title if you search. It was fbody t-56, 4.11's and 28" Hoosiers. The car made 665rwhp 760 ftlbs on nitrous, but was a slip n slide down the track.

Sounds kinda scary lol. Your car make's alot of torque. That is on the heavy side but its not too hard to make these cars weigh alot. I will have to check out your videos man thanks. Mine is under nmassengale399 on youtube. I have older videos on streetfire.net under nmassengale399 also. A good bit of the videos are for the lsx shootout and holley ls fest with other people making runs.

I never saw much more than a little daylight under the tires of my car. In some of the side/rear go pro videos you can see the car raise up and the tires not spin (off the ground) for a very split second and then get right back on the ground. The suspension needed much more attention to get it dialed in. But I always had fun with it running mid-high 10's

That's all that matters is havin fun. Seems like everytime i go to the track i am trying to get something to work right lol. If it wasn't for that i would get bored. I am hoping when i build the 347 or whatever i will be able to run mid to high 10's but who knows. The plan was to shoot for 9.99 but that seems like way too much at this point. The cam i got is a decently aggressive solid roller but still streetable and some trickflow 215's. It was made to peak around 6700 and shift around 7200. Suspension setup will be the key for me to get even close to that et tho.

Also on a tnt night, most cars at the track I race at, are no where near 10 sec cars, there's a few here and there but most are a good 1-1.5 seconds off from what I run. Mainly due to the fact that they started enforcing the 11.49 roll bar rule. Prior to that, there was some decent racing on a friday night TNT but those cars dont even come out because they dont want to cage their cars.

Mine would 60 ft in the 1.9x's and above at any of those tire pressures you posted lol. Mine likes 11 psi cold and 12 psi hot up to 13 psi. Anything much above that and it spins like i am on ice. My car likes a 5000 rpm launch...Gets me a high 1.5x 60ft 90 percent of the time.
Our setups behave quite differently. The attached graph shows my bog after launching at 5700 rpm with 19.5 psi in the ET Streets. Also, the variation in track conditions I experience makes the consistency you mention nearly impossible. I usually need a test pass or two before I'm ready to be eliminated. My chart data includes these test runs. Does your 90% figure include all your runs?

Also on a tnt night, most cars at the track I race at, are no where near 10 sec cars, there's a few here and there but most are a good 1-1.5 seconds off from what I run. Mainly due to the fact that they started enforcing the 11.49 roll bar rule. Prior to that, there was some decent racing on a friday night TNT but those cars dont even come out because they dont want to cage their cars.

I believe if they started inforcing needing a cage, jacket or other things, then nobody would come out to my home track either. They would probably go out of business to. I am not sure how fast the cars are at my track tho, they won't show times because of all the grudge racing and street racers.

Our setups behave quite differently. The attached graph shows my bog after launching at 5700 rpm with 19.5 psi in the ET Streets. Also, the variation in track conditions I experience makes the consistency you mention nearly impossible. I usually need a test pass or two before I'm ready to be eliminated. My chart data includes these test runs. Does your 90% figure include all your runs?

Its not all my runs, i have been trying to slow my car down for the 12.00 index in lsx challenge series but basically when i want the car to 60 ft good it will. Sometimes track prep gets bad and i dip into the low 1.6x's or it just spins lol. Track prep is always decent or good where ever i run at. Home track seems to hook the best for some reason.

That is some ridiculous bog you have man. You get way out of your power band.

Here is a run where i cut a 1.56 60ft. launch rpm is 5500.

http://i991.photobucket.com/albums/af35/nmassengale399/Hptunersshotofarun.jpg

Its not all my runs ... but basically when i want the car to 60 ft good it will. Getting a manual transmission car to launch consistently is not easy. I have several theories about why my sixty times are inconsistent. I’m sure they would be somewhat more consistent if I had a 2-step. Another possibility is that ET Streets are less sensitive at the lower pressures you run. Then there's the outside possibility that my car would be more consistent if you were driving.

2 step will exponentially help your launches.

http://i991.photobucket.com/albums/af35/nmassengale399/Hptunersshotofarun.jpg
Oh, and thanks for the data log. I've heard guys talk about power shifting but this is the first proof I've seen.
-Gary

2 step will exponentially help your launches.Good to hear. I've resisted because I thought I could learn to recognize the sound of 6000 rpm. Also, I don't know anyone who has a 2-step. People around here think they're sophisticated but most don't know squat about drag racing.

That is some ridiculous bog you have man. You get way out of your power band. I hate the sound and hesitation but bogging sometimes works for me. Bogging is certainly much better than wildly spinning. I classify my launches into three categories: a deep bog, a no-hook spin, and in-between, which I call a hooking-spin. The attached chart shows my five lowest ET runs superimposed on one another. In the five launches I have two bogs (blue, green), and three hooking-spins (red purple, turquoise).

The numeric data for these runs is:

Sixty ET Speed TirePSI LaunchRPM
1.559 11.534 118.56 19.0 6069
1.612 11.541 119.39 18.0 5697
1.604 11.577 120.34 19.5 5762
1.568 11.577 119.53 19.5 6735
1.653 11.582 119.02 19.0 4907

I hate the sound and hesitation but bogging sometimes works for me. Bogging is certainly much better than wildly spinning. I classify my launches into three categories: a deep bog, a no-hook spin, and in-between, which I call a hooking-spin. The attached chart shows my five lowest ET runs superimposed on one another. In the five launches I have two bogs (blue, green), and three hooking-spins (red purple, turquoise).

The numeric data for these runs is:

Sixty ET Speed TirePSI LaunchRPM
1.559 11.534 118.56 19.0 6069
1.612 11.541 119.39 18.0 5697
1.604 11.577 120.34 19.5 5762
1.568 11.577 119.53 19.5 6735
1.653 11.582 119.02 19.0 4907

Bogging the car is good for bracket racing as long as it consistenly bogs the same amount each time. I tried to get the car to bog at the race in Commerce, Ga to slow it down some but it had way much effect on 60ft. As long as i launch around 4500 to 5500 rpm with 11psi cold tires and around 12 to 13 hot, the data log will look like i posted. I can usually get my car to run within .025 quicker and slower with the exact same tune as long as the density altitude does not make a big change.

That track outing from that graph i posted, i ran from 11.74 to 11.82 as long as i did not miss a shift. It would be from 11.74 to 11.79 if that 11.82 run was not in there, i did not have to much air in the tires or the track wasn't as sticky, not sure which one. It would have been even more consistent if i wasn't changing the tune up.

Those runs you posted were on separate track outings right? Is your car more likely to hookspin or bog? How consistent during a track outing is your car?

Also from the looks of that graph that you might be able to get the car more consistent with a 2 step. Not sure tho but i know it makes it easier on me to have one rather than searching for rpm while trying to consentrate on the tree. If you can get your car to either just bog, or just hookspin and not both during a track outing it should get more consistent also, at least i would like to think it would.

2 step will exponentially help your launches.

This!! It is one less thing you will have to really think abotu on the line. Set an RPM your car likes and then make suspension and tire work with it. The less things you change it will be easyer to make the car work. Changing Launch, Tires, Shocks all at once you wont ever learn what works and what doesnt. At 6300 my car cuts 1.47-1.49 60s all day on a decent track. Go to a better track I gotta leave higher.. I really hated the thought of it at first but once you get it and learn what the car likes its priceless..

LS1Tech is still great. I started this thread thinking my launch data might help a few beginners. It turns out I’ve learned a few things myself. Somehow I wasn’t fully aware that consistent, low sixties are possible with a manual transmission. We all know the easy way is with an auto but what fun is that? Thanks everyone.

Those runs you posted were on separate track outings right? Is your car more likely to hookspin or bog? How consistent during a track outing is your car?Yes - the graph of my five lowest motor ETs shows runs from three different days - two runs one day, two another day, and a lone good run the third day. So I am able to achieve some consistency although not the kind of consistency you and others have described. I do believe a 2-step will help. One reason I run higher tire pressure than you (aside from the fact that higher pressures work better for me) is that I want never to bog. I usually air the ET Streets to 20 psi cold before my first run and lower the pressure if I get too much wheelspin. I'm always trying to find the sweet spot between useless spinning and dead-hook bogging. Some days the track is super good and I bog from a 7000 rpm launch with 19-20 psi in the tires. A bog can give me a 1.5x sixty but I still won't like it. Bogging from a 7k launch is brutal clutch punishment.

Beginners sometimes ask what type of tire works best with a manual transmission. The attached graph shows my sixty experience with drag radials. I have relatively few data points for DRs because I soon discovered that bias-ply ET Streets work much better. My best result with DRs was a 1.786 sixty, launching at 2500-3000 rpm on BFG 255/50/R16s @ 22psi. I toasted a clutch trying to repeat that launch.

Yes - the graph of my five lowest motor ETs shows runs from three different days - two runs one day, two another day, and a lone good run the third day. So I am able to achieve some consistency although not the kind of consistency you and others have described. I do believe a 2-step will help. One reason I run higher tire pressure than you (aside from the fact that higher pressures work better for me) is that I want never to bog. I usually air the ET Streets to 20 psi cold before my first run and lower the pressure if I get too much wheelspin. I'm always trying to find the sweet spot between useless spinning and dead-hook bogging. Some days the track is super good and I bog from a 7000 rpm launch with 19-20 psi in the tires. A bog can give me a 1.5x sixty but I still won't like it. Bogging from a 7k launch is brutal clutch punishment.

One reason i have good consistency i think is also running speed density. Which has to be tuned with different density altitude.

On a set of 295/55/15 MT DR's i've gotten a 1.72 NA, but could only keep the 2 step at around 3200 and had to slip the clutch vs either a dump or very quick slip around 5k on the bias plies. DRs are really tricky on marginal tracks and still require a lot of adjustment to the suspension on good tracks with a manual. Takes a lot of passes/seat time to get it right. Lighter cars help out as well

kinda deviating off topic, but are you guys launching on a build t56?? All this info makes me realize i need to make some changes at my next track visit, but i'm sure my t56 is pretty much stock (other than clutch/cmc)

Nobody has mentioned front shock settings in this thread. Any thoughts?

kinda deviating off topic, but are you guys launching on a build t56??My T-56 has all stock innards with the exception of billet keys and a steel 3-4 shift fork. My hydraulics are stock except for the “drill mod”. A more or less stock T-56 is sweet up to at least 550 rwhp if you have a good, properly installed clutch.

Nobody has mentioned front shock settings in this thread. Any thoughts?The general rule for front shock settings is stiff compression and loose rebound but you really need to experiment to find what works on your car. Be careful with front shock settings, especially if you have skinnies and no front swaybar.

The general rule for front shock settings is stiff compression and loose rebound but you really need to experiment to find what works on your car. Be careful with front shock settings, especially if you have skinnies and no front swaybar.

Agreed. With my Strange DAs upfront, adjusting them close to full loose on rebound (extention) seems to affect the compression in a negative way. In other words, with compression set to close to full stiff, rebound full loose, the shocks seem to be way to soft on compression. It feels like they may bottom out real easy and of course the front end does lift real easy as well, which I expect. So, I was courious what you guys had for your settings.......may help me with a baseline setting.

Agreed. With my Strange DAs upfront, adjusting them close to full loose on rebound (extention) seems to affect the compression in a negative way. In other words, with compression set to close to full stiff, rebound full loose, the shocks seem to be way to soft on compression. It feels like they may bottom out real easy and of course the front end does lift real easy as well, which I expect. So, I was courious what you guys had for your settings.......may help me with a baseline setting.

Stock bilsteins here. Not sure what mine could pick up on 60 ft with some double adjustables and a different spring up front. If you watch in some of my video's the front suspension is fully extended but does not lift a tire. I am thinking mine would raise up a little quicker getting more weight to the rear tires earlier.

Right now i am interested in changing the instant center on the car, basically to see if what hitting the tires harder will do vs lessining the hit. I know i need a drag bar badly tho.

Also running a stock gto t56 for the other guy who was wondering. Mine is only a bolt on car so not much power to break it here. The gto t56 has a few better internals than the fbody t56.

My T-56 has all stock innards with the exception of billet keys and a steel 3-4 shift fork. My hydraulics are stock except for the “drill mod”. A more or less stock T-56 is sweet up to at least 550 rwhp if you have a good, properly installed clutch.

i'm just a little worried about launching the car on what i'm assuming is a stock t56. I don't power shift, and i'm only putting 405rwhp, but i've heard of people destroying output shafts and other stuff with less.

Also running a stock gto t56 for the other guy who was wondering. Mine is only a bolt on car so not much power to break it here. The gto t56 has a few better internals than the fbody t56.

yeah apparently the mn12 is stonger, and the guy i bought my moser 12 from was putting 740hp through a stock mn12 without a problem.

Anyone else here clutch dumping over 4k and cutting < 1.8 60 fts on a stockish t56?? (without breaking?)

I would recomend taking some air out of the tires, I ran my bias plys much lower than that. once you get to the point where your car starts bogging you can pic up the launch rpm. Once you get a bit better 60 ft times you will be able to be more consistent. My 6 speed car does 1.40~1.45 on what ever track its on and that is with 28x10.5 mt stiff side wall slicks. It does the same on 26x10.5 hoosier slicks

i'm just a little worried about launching the car on what i'm assuming is a stock t56. I don't power shift, and i'm only putting 405rwhp, but i've heard of people destroying output shafts and other stuff with less.

I had a friend bend the splines on his output shaft. The yoke was stuck on there and could not pull the driveshaft is how he found out lol. His car was cam only trans am. Not 100% sure why it happened, would like to say it was because of the wrong length of driveshaft.