Track results - couple of questions

[casey02ws6]

OK so I made my 2nd trip to the track - this time armed with more power. I was a little disappointed but I think the car has a lot more in it with a couple of adjustments. My best run was as follows:

60' - 2.236
330' - 5.812
1/8 - 8.681
MPH - 87.96
1000' - 11.109
1/4 - 13.189 - 107.86

I was trapping at 108-109 with just a lid and cat back so I know something is wrong. I had Bill (computer tunes LS1s) ride with me with HPtuners running to see what was up. Looks like everything was running perfect. So he took it down the track 2 times. first time was a 12.99 - 2nd one was:

60' - 2.201
330' - 5.73
1/8 - 8.535
MPH - 88.01
1000' - 10.925
1/4 - 12.939 - 111.55

I welcome observations from you guys - a lot of experience on this board!! Here are my guesses - first of all this is on street tires at 30+ lbs (I was trying to protect the clutch / rear end as much as poss) - could shave some 10ths off with DRs or even lowering pressure to 20. I was not shifting at the new redline (6600) because I know the factory tach is slow in 1st and 2nd - I should have however relied on the tach in 3rd - I was short shifting it - which is why Bill ran away from my time after the 1/8th. My final observation (as suggested by Bill) is my clutch is slipping a bit when the motor hits max power which could explain the low traps (I expected to see traps at ~ 115). We saw this on the dyno - on the dyno graph the power line gets wavy at the peak - slipping clutch is one explanation.

[casey02ws6]

Also no suspension mods at this time. This is definitely my next round of mods - starting with SFCs and LCAs. I will then look for a clutch and start saving for a new rear end

[Dave Vince]

60'

That 60' time is pathetic. That is where your problem is. Put on some Slicks or MT drag radials, and I think you will see the performance you expect. That dyno reading sounds very optimistic for the trap speed you are turning. 312 hp at the rear wheels, with a 22% drivetrain loss is a realistic power output if your car weight is 3700 lbs. (typical weight for these cars). Dynos lie all the time, but the track speed never does. However ET will depend on quite a few factors.

[fastTa]

4th Gen F-bodies with a MN6 T-56 and the stock 10 bolt only see about a 14.5% drivetrain loss. 22% would be indicitave of something like a Th400, steel driveshaft, heavy duty u-joints, and 9" Ford rearend, and larger tires.

Not too bad Casey. I expected some higher trap speeds as well, but it sounds like you are still learning to drive the car so they may change with a little practice. C,mon, lower that tire pressure a little and leave with a 5k clutch dump!

Go with a McLeod or Textralia clutch. The Textralia is getting really good feedback so far.

[casey02ws6]

The dyno numbers are not off - they are very consistent with all that I have read. This exact set-up gave my friend a 12.00 at 118 MPH on DRs- by same I mean the same cam / headers / pulley - I bought them from him. My car dyno'd within 3 RWHP (383 vs 380) of his car.


As far as clutch - I have heard a lot of good things on the Cartek clutch. I will look at the McLeod and Textralia.


The 60' time is very soft - but not terrible on street tires - I have run a best of 2.19 but that was last year with 50+ HP less. On drag radials 1.8-1.9 will be what I am shooting for.




Biggest problem I think: I wanted to drive it home .

[Jay 02 TA ws6]

Casey, you gotta stop being so nice to it. The time to baby it is before and after the track, not AT the tack!!!

You gotta drive it like you are mad at it

The 60' definitely has room for improvement, but you know that already. 2.1 is an "average" time on street tires. You seem to have pretty similar goals that I had when I owned my car - I didn't want to set the car up for a straight-line only, and I didn't want to make it unstreetable either - so I hated the idea of slicks or DRs. I wanted to see what I could run on the street tires.

Get either a tach or a shift light so that you don't need to short-shift, and get a new clutch that can get all the new power to the ground and you'll be where you want to be

By the way... 6600 RPM redline is pretty cool

[Jay 02 TA ws6]

That 60' time is pathetic. That is where your problem is. Put on some Slicks or MT drag radials, and I think you will see the performance you expect. That dyno reading sounds very optimistic for the trap speed you are turning. 312 hp at the rear wheels, with a 22% drivetrain loss is a realistic power output if your car weight is 3700 lbs. (typical weight for these cars). Dynos lie all the time, but the track speed never does. However ET will depend on quite a few factors.

Dave... for his mods... 312 rwhp? You can't be serious...

[casey02ws6]

You nailed my goals exactly - fast street car that I can drive every nice day if I want to. I did not want to lose the car for the summer - I do not have the funds right now to replace a shattered clutch or a grenaded rear end We have another drag day in September - I can live with a broken car in the garage all winter.


I am surprised Joe has not jumped in on the "no suspension mods" comment. If I remember right Joe accomplished about the same times on a nearly stock LT1. The power is there I just need to learn to get it to the pavement.

[Jay 02 TA ws6]

I did not want to lose the car for the summer - I do not have the funds right now to replace a shattered clutch or a grenaded rear end

Well of course I never wanted that either... but it's a risk you gotta be willing to take when you track it! Otherwise, you're going to end up disappointed in your times. And I think you are underestimating the toughness of your car a lil bit too... Let 'er rip!!!

Come to think of it... if memory serves me correctly... someone I know used to give me a lot of s$%t for not being able to run a 12 second timeslip with my car at 345 rwhp. I think... his name started with "C" and ended with "asey"... but I'm not sure.

And that was with 40 less RWHP!!!!

hahahahahaha

ZING!!!!!!!!!!!!!!!!!!!!!!!!

[ws6drbob]

Get a stage II clutch and let er' rip I will personally be buying a Mcleod within the next month or two so. Can't wait to put the new flywheel, stage II clutch, and loudmouth on then take er' to the track

[casey02ws6]

Well of course I never wanted that either... but it's a risk you gotta be willing to take when you track it! Otherwise, you're going to end up disappointed in your times. And I think you are underestimating the toughness of your car a lil bit too... Let 'er rip!!!

Come to think of it... if memory serves me correctly... someone I know used to give me a lot of s$%t for not being able to run a 12 second timeslip with my car at 345 rwhp. I think... his name started with "C" and ended with "asey"... but I'm not sure.

And that was with 40 less RWHP!!!!

hahahahahaha

ZING!!!!!!!!!!!!!!!!!!!!!!!!

OK - I knew that was coming - and I deserve it! It was all in fun though - these cars are just so much fun. I do think it is tougher than I give it credit for - it seems like every story you read is a story about breaking something - but then no one writes about their car holding together. I am glad to see you are still posting here!

[Dave Vince]

RWHP

Most of you seem to put a lot of stock in these rear wheel dyno readings. I do believe that dynos are good for tuning purposes if you use the same dyno, make chages and see the result. However I would not take the readings as Gospel. The weight of your car divided by your drag strip MPH is a more reliable indicator. There are ways to calculate this by dividing MPH, not ET, by your vehicles weight. There was an earlier post where one rear wheel dyno read almost 100rwhp difference from another. This would tell me to not take the readings to seriously. I will be taking my car to the track, as soon as my drag radials get here, and the MPH in the traps will tell me how much power I am making. If you can beat me at the track I salute you. If your dyno reads more than mine, big deal.

[N20LT4Bird]

THe reason why I said 110 mph traps before is because you were dyno testing on a dynotech as i remember.......these dynos are notoriously high. Not that 110 mph traps is slow.....THATS MOVING. You should have a low to mid 12 second car if you can hook it. Remember, for every .1 on the 60', it's .2 on the ET. So, if you can drop it to a 1.8-1.9 60', you be looking at a 12.3 or so. You have the same problem as me.....cant hook it to save my life! On street tires, you really cant hope for more than a 2.0 or MAYBE a 1.9.....if youre good. Get some ET streets and just roll out of the hole and mash it. If you want to avoid grenading the rear, than just dont DUMP the clutch.....

[Jay 02 TA ws6]

Most of you seem to put a lot of stock in these rear wheel dyno readings.

What you are suggesting his actual rwhp numbers are is a little crazy. If 312 rwhp was correct, he'd have 367 hp at the crank - that's a barely noticeable gain over a stock LS1. I'm not sure why you don't believe he is having problems. I trapped 109 mph into a 25 mph headwind in my LS1 with no internal mods whatsoever. Clearly, when his trap speed is lower than stock, there is an anomoly here.

If you can beat me at the track I salute you. If your dyno reads more than mine, big deal.

I agree with you here, but I think you should understand a car with his mods should be mid-high 12s easily on street tires, and trapping closer to 115 mph. All you have to do is go here: www.ls1tech.com to find plenty of examples of similar cars running such times.

Casey's absolutely right - he has some issues to work out... by no means are his times where they should be.

[Jay 02 TA ws6]

THe reason why I said 110 mph traps before is because you were dyno testing on a dynotech as i remember.......these dynos are notoriously high. Not that 110 mph traps is slow.....THATS MOVING. You should have a low to mid 12 second car if you can hook it. Remember, for every .1 on the 60', it's .2 on the ET. So, if you can drop it to a 1.8-1.9 60', you be looking at a 12.3 or so. You have the same problem as me.....cant hook it to save my life! On street tires, you really cant hope for more than a 2.0 or MAYBE a 1.9.....if youre good. Get some ET streets and just roll out of the hole and mash it. If you want to avoid grenading the rear, than just dont DUMP the clutch.....

380 rwhp DynoJet cars trap much higher than 110. My 345 rwhp dynojet car trapped 109.98....... and even that is a bit low.

I guess we'll have to wait for Casey to work out all the issues - new clutch and new tach - before you guys will believe it. I'm not sure why though... there are plenty of examples of cars with his mods and the times he SHOULD be running out there.