Going to E-Town this coming Saturday and it will be the first time that I drag the Z (or any manual transmission car for that matter). My car is making 600 RWHP, running the stock clutch and is running new Michelin PS2 runflat tires. My question is regarding launch technique and traction control. How high do I rev the engine before releasing the clutch? From what I understand anything less than a nice slow release will result in bog? Also should I drop the rear tires to 20 psi? As far as traction control what is the optimal setting and what is the setting that will keep me from ending up in a wall? My mods are listed in my sig. Thanks in advance.

 

Some of the manual guys will be in here shortly to offer you some valuable advice/info but I just want to tell you to be VERY careful with that kind of power in such a light car with street tires, don't try to set any records on your first few passes out there.

 

I'll be there also, but I'm "Automatic" and am using DR... If you are running the OEM Runflats, I (personally) wouldn't lower the air pressure to less than 28 lb...

My reasoning is they (the OEM) run flats have a very stiff sidewall, and lowering the air pressure ain't gonna do much.. in fact it may cause you to encounter the dreaded "Wheel Hop"

I've been racing an Auto the last 15 yrs, so I cant be much help to you on advice with a manual. however

I Can Say For SURE!! 1. if you get any wheel hop push the clutch in instantly and let off... thats how the guys bust rears..
Also if you encounter spin and the car is going straight just "modulate the gas until it stops spinning and then put the wood to it...

2.If you feel it getting sideways "GET OUT OF IT!!" the runs is NG you have a slow ET and worse you may have a "Close Encounter" with the wall... Trust me I have seen many guys hit the wall just as they were shifting to 2nd gear.... & the wall is very unforgiving...

You can always make another run... There are quite a few guys who run stick cars who can give you some good info on launching... I'm only telling you the things I "KNOW" for sure..

Will you be running the 12.50 index... thats the class I plan on entering... but at my "Advanced Age" I have very little chance to react to a .500 Pro Tree... I have to depend on the "Mercy" of the other racers... maybe they will feel sorry for the "Old Fart"

Look me up when you get there I have a LMB C6 with NY plate ILLEGL should be easy to find...

See ya Sat..

 

Since this is your first time out in a manual trans, I'll layout a safe gameplan for you. I've had approximately 400 launches on my C5Z and C6Z.
1. The rear tire pressure should be set to 26 psi. This should not alert your sensors. Weird things begin to happen at less than 24 psi.
2. Set the traction control so it is off but the active handling remains on.
3. Drive around the waterbox. No sense doing a burnout yet.
4. The stock clutch is terrible in these cars. The first couple passes should be like you are trying to leave from a traffic light. This should mitigate most of the bog and get you started. This will also assist you in mitigating that dreaded wheelhop. Any sign of wheelhop, back out of it. Wheelhop is where the tire is in between traction and spinning freely.
5. Once you feel comfortable with the car, you can launch at a higher rpm; however, be very careful. You will get a bog, so do not get disappointed. You can start between 2500 and 3000 rpm and use a smooth somewhat quick release but not a dump. The pedal should be slightly off the floor but not engaging the clutch. If it engages, it will overheat. If it is too low, you'll shock the drivetrain. It should take approximately 1 full second for the clutch pedal to travel to the top of its stoke. (If you ride out the clutch, it will stick to the floor.) Once the clutch is released and you are moving without spinning, you can squeeze the throttle. (Throttle before the clutch is all the way out, will stick it to the floor.) Etown is not known for its track prep, so you may spin and then bog. That's okay for now.
6. As stated above, the LS7 clutch sucks and it will take time to master. Plan on changing out your clutch fluid prior to getting to the track and making changes every 2-3 rounds. This will assist in the mitigation of the dreaded clutch pedal sticking to the floor woes. Go to the C6Z section and read Ranger's sticky on this. http://www.rangeracceleration.com/Clutch_Care.html Ranger also has a website discussing launch technique. http://www.rangeracceleration.com/Launch_Tips.html
7. I would go to the test and tune lanes so you do not focus on that tree. Technique is much more important.

Good luck. Let us know how you make out.
P.S. - I'll be happy to further assist once you get this under your belt. The important thing is to have fun and get down the track. We can cut some low 1.8 60's later.

 

That some good advice mitigated by Gary!
I agree w/ lowering the rear PSI to 25-26, forgetting the tree, quick clutch release and driving round the water. The stock clutch IS terrible for high RPM launches OR high RWHP cars! The only good thing is it will prevent you from braking at your RWHP, most likely.

Do a short no-brake "rolling burnout" (TM Dr.Ron) to clean the tires off & heat them up a bit.

At your RWHP, do NOT expect to go full throttle until well into 3rd gear. I've driven a car near your RWHP on street tires, and not only did I have to walk it off the line, but I had to short shift 1-2 & 2-3 before I even thought of putting my foot into the throttle!!

Good luck!

Ron

 

Excellent advice Ronnie.
for pointing out the use of mitigate.
BTW- You only used five "I"s this time.

 

I think if the OP plans on coming to RP more than 1 or 2 times, he should invest in a set of MT Drag Radials..

Its a shame to have all that HP and not be able to use it...

 

I don't. I'm a once per year kind of racer, extremely not-handy and rely on The Vette Doctors for everything when it comes to the maintenance and installation for the car. I even have a pair of LED taillights sitting on my floor for over a month waiting for the next time I go see them because as easy as it may be to install, I would find a way to mess it up. Just like to have the power to back up the looks.

 

Thanks to all for taking the time to give their input and advice.

 

The great Carnac strikes again.

 

.......it was well taken and appreciated.

 

And you talked me into this. You owe me an hour.

 

Had a lot of fun however I certainly realize again (should have learned the first time with my C5) that pumping money into a car to make a lot of HP doesn't automatically make you faster than the next guy. My best run was 12.1 @ 125.2 MPH. I had lousy 60' times and inadequate reaction times but nonetheless I thought that 600 RWHP would equate to a 130+ mph trap speed but that was not the case. My average of 6 runs was approx. 12.4 @ 123.8 MPH. Now I'm far from a good driver and certainly don't have the seat time in the car at the track but damn I spent a lot of money and was hoping for better results. My friend who makes 60 less hp to the tire, running 20" chrome rims all around, no less, ran a 11.45 @ 125.5. So I'm a bit baffled but all in all it was a fun day had by all.

 

Seat time is what you need. and use Gary's advise. He knows how to launch these cars...

Glad you had a good time. You should join us at the next challenge event - August 14th.

 

Thanks, it was definitely a rush. I have no doubt that with more seat time, better tires, clutch and maybe some cool air.....130+mph trap speeds are definitely there to be had.

 

Hell to add to that, I drive on the street with the BFG drag radials all the time. Why? Because they hook up on the street while the street tires do not and they the DRs have a stiff sidewall so handing is not compromised at all. I find that running on street tires is absolutely dangerous -- going sideways at 60 MPH at WOT is not my idea of fun.

 

At least I only used ONE form of I, and NOT 3 (mitigate, maitigation, mitigating)!!

Throwing $ & RWHP USUALLY doesn't reduce ET's. Driver mod should always be the FIRST mod.....Even Gary would agree with that!

Ron

PS-_ was describing what _ do for him...._ can't describe it without saying _!!!

 

Total of 5 runs:

Average 60' was 2.309
Average 1/4 mile time: 12.326
Average Trap Speed: 124.324 mph

Best run was 12.125 @ 125.35 mph

Average reaction time (for whatever that's worth): 0.695

 

Disclaimer: not a 1/4 mile car, please don't judge

Edit: I know this thread originally asks about launching, which I know nothing about Just trying to help the OP determine how his setup is working

My only pass on my new setup (402+D1SC, 708rwhp) with pure street tires (all weather nonetheless ) netted me a 12.1 @ 133 and a half mph. 2.4 60' and 100.02 mph in the 1/8. I picked up 33.5 mph in the last half and think I may still have lost a bit due to granny shifting (stock tranny).

 

Thanks. Now I don't feel so bad.