New slicks, but which ones?

[bobb428]

I totally agree with Dale! The biggest thing is to not put water where you don't want it! I do 3rd gear burnouts with a 3.05 1st & 5.14s. 2nd seems to drag down to much for how my clutch is set up. A wisp of smoke is perfect as long as I didn't put water in the wells!

[Posi67]

I think this is a great thread but one where there is no consensus since everyone's deal is different. 3rd gear burnouts with a Jerico aren't advised because from what I've been told (by Jerico) is that the 3d gear is on the weakest part of the mainshaft. I'm no transmission expert so can't confirm that. What I do know is what TomP stated that with a Softlok a 3rd will eat the clutch if you don't have enough RPM, base pressure, counterweight or water in the box.

Shocks are another thing I've run the game on. Some have great results with a 90/10 front and basic back. Mostly auto cars or big back tire.  I had the Calvert/Rancho rear..  didn't work. Had 90/10 front and switch to the Calverts… didn't work. Single adjustable front and double back and things started to come around. Double adjustable front gained zero but then the tire and clutch adjustment come more into play.

I'm still not comprehending the front end topping argument as Doug mentioned. It's been posted as gospel that you need X amount of front end drop for a car to hook but if you look at a lot of Stock and SS car launches with the wheels in the air it's obvious they have the front end tied down. I have mine somewhat limited but as for topping out.... if you pick the front end off the ground, it's going to top out at some point. You just don't want your front shocks to be the limiter.
 

[cjshaker]

Thanks for the input, Dale, and everyone. I've considered before about cars that lift the front off the ground, which there's no shortage of in Stock and SS as you mentioned. I came to the conclusion, rightly or wrongly, that it depends on how fast it rises. When I watch cars that do it successfully, they seem to rise gradually, so there's a smooth transfer of all that weight (abeit, still fairly quick since things happen fast). On the other hand, my car seems to rise extremely fast, so I wondered if the car was hitting the limit and upsetting the rear? Or I could be imagining that and totally full of it..lol I had not considered if my shocks were acting as the limiter, so I'll check that out and add a limiting device if needed.

When I watch my in-car video, I can watch my body push back as the front rises and the tires grip, but I can also see that force let up (my body moves forward and the nose drops slightly) before the car is in full motion going forward. That has to be upsetting the rear, and I'm thinking if I can slow that down, it should help. Actually, now that I think of it, if I could stiffen the compression on the shock, that should help keep the front end up also.

You can watch what I mean in this video, which I've started just before the launch...
https://youtu.be/7NoKofCDF2Q?t=74

Here's a crop of my launch at Beaver last year. You can see that I've got decent compression and wrinkle on the tire. This is right at the peak of my front end rise.

[BattlestarGalactic]

Stock and SS have their shit together.  It takes a lot of tuning to get their cars to leave hard, especially with a small tire.  They have their clutch tune up to perfection to allow the tires to get hooked and stay hooked.  That and shock adjustments.

I found out about front end rise with my car.   That is why mine sits on the bump stops and has 8" of travel before the wheels leave the ground.  Though my car is a few feet longer then most other race cars.  I also have to control front end rise.  I used to have 90/10.   Buddy with '70 Mustang runs generic MonroeMatics and can grind the rear bumper off at will.  So, knowing that I put a set of generic shocks on the front and the stiffness helped slow the rise and it helped with my 60ft.  That is when I bought QA1 SA shocks and that really helped!  I should have bought DA because I need some resistance as the car falls back to earth!

Agree, with a big tire, automatic car front end rise isn't as critical.  A hard hitting stick car with smaller tires it is more critical.  If the motion tops out too quickly the forces applied to the back tires diminishes and once the clutch locks up it will want to spin the tires.

As for what gear and why.  I know that any gear in the MIDDLE of the shaft will be the weakest due to deflection.  That is likely why Jerico says don't use 3rd gear.  A Nash/GF have handcuffs and bearing supports in the middle so gear choice is not as critical.  But, like mentioned, I don't like to hit the clutch that hard using a higher gear for a burnout(remember my car is 500# heavier then most also).   Some places there is a lack of water and I don't want to have problems so I use 2nd gear and it works fine for my car.

[Rory428]

Echoing the others, with light pressure clutches, I do my burnouts in 2nd gear, as a lack of water can hurt the clutch really easily. And as others have mentioned, on a Jerico, or most production based stick transmissions, 3rd gear is the weakest, as it is the furthest away from the mainshaft bearing, so it can spread away from the cluster. I broke my Jerico DR4 3 times in 20 years, and each time, it was in 3rd gear.One of the main reasons for my switching to a G Force G101A was the fact that the G Force has a "handcuff" that connects the front section of the mainshaft to the cluster, to prevent the shafts from deflecting. Like Larry said, my old Nash 5 speed had a pair of bearings in the center of both the cluster and the mainshaft, for added support. .

[Posi67]

Front end rate of rise has me as confused as Doug. I agree that a slow power wheelie looks great but we do all sorts of stuff to loosen the front end components then don't like the fact the car jerks the front tires out of the beams. Mine doesn't repeat run to run but I'm sure some of my Red lights have been because the front went up before the care moved forward. Another reason to stage as shallow as possible.

[cjshaker]

Yeah, it occurred to me while thinking about all the responses here that, while I'm talking about slowing my front end rise, I just invested in roller control arms and roller spring perches. Why? Because of all the talk about making sure your front end is as loose as possible to aid in weight transfer. Apparently, spending money so that you can work backwards is part of racing. Good grief.

[John67427]

Doug,
 A lot of good advice for you and you seem to have a good grasp of what to do. I agree with the front shock change as opposed to a straight 90/10 set up. As far as gear selection for the burnout you do what works for you. I am the same as bobb428. I tried 2nd gear and it will toast my clutch set up. Before I knew about the 3rd gear weakness of the Jerico I had done it for over 10 years.
 You’ll get it figured out it just takes time.

[cjshaker]

Thanks, John. The biggest difference came from increasing my starting line ratio. That helped tremendously with getting off the line without blowing the tires off. Since I typically only race a couple times a year, it's a slow process for me. I'm hoping to make some progress at the Reunion and the Dragway 42 event before hitting Drag Week again this year.

Thanks to everyone for your replies.

[BattlestarGalactic]

Yes, having a free working front end is good.  BUT, it needs to be controlled also.  All the roller stuff helps make it move full travel without any kinks.  Really good for road racing.  They too use a lot of travel and must control it with shocks. Tomatoe, tomato.

With a much lower powered car, that doesn't need much chassis work to make it go, quick up is fine.  Say a 12.0 footbrake car.  Jump the nose up to plant the rear tires and let it go.  Power is already applied and won't typically overcome the tires.

Now change that to a more powerful stick car with small tires.  Everything needs timed properly to get the car to move properly.  This is JUST the reason so many racers DON'T want to race a stick car.  Too much work.  LOL!!  Even my friend with 18x33 tires has traction issues sometimes with his 9.0 car.  It's good for most tracks, but can also blow the tires off at others.  Though he hasn't graduated to changing clutch tune or shocks.  He doesn't race enough.

My .02 is since the clutch is hitting so hard, you need more chassis control to help get it moving.  If you could lighten the clutch then chassis isn't so critical.  I'm literally in the same boat.  I'm still trying to get clutch out of my at launch.  Especially with the new motor making MORE torque at lower rpm.  Ugh.

At Thompson, first race after new motor, car went 1.40 60ft(best ever).  Then go to DW42 and it blazes the tires uncontrollably.  Go figure.  At Thompson I left at 5K or more>  DW42 I'm at 3500 and dropping it each pass trying to get a hold of the track to get even close to mid 1.4 60 ft.

[Posi67]

Yeah, it occurred to me while thinking about all the responses here that, while I'm talking about slowing my front end rise, I just invested in roller control arms and roller spring perches. Why? Because of all the talk about making sure your front end is as loose as possible to aid in weight transfer. Apparently, spending money so that you can work backwards is part of racing. Good grief.

Nailed it.... LOL

Track prep always makes me mental. Where I generally run it starts out good then goes away as the day wears on. Track goes away and the clutch gets hot and more aggressive which is not a good combo but then the air also goes away later in the day so one would think a bit less power would be a wash with the setup. I don't have data logging and not interested in big adjustments during the day.

Some of the "hot" racers pull timing out in 1st gear to kill some power then it comes back in down track. Too complicated for my simple mind so I try and make do. Nothing more annoying than having one run hook then the next shortly after blow the tires off. We can't do anything about prep stuck with what the track gives us.   

[bobb428]

Here is something a lot of people don't know about yet. These are GoodYear radial slicks intended for a clutch car. I was out at the Vegas Div7 race in November and Markus was out testing them. He was dead hooking every pass running 10.20s.
D31I4281 (2) by Bob Smith, on Flickr
DSC_0219 (2) by Bob Smith, on Flickr

[338Raptor]

Any idea what size tire that is and the pressure he was running?

[Joe-JDC]

I guess my cars were never fast enough to worry about pulling the wheels, but I did run in the 10's with my Mach I, and I don't have a single picture of the wheels up off the pavement.  I was always taught that pulling the wheels is lost motion, and ultimately is slower the higher it goes.  If you watch the cars that run really quick times, many do not even lift the wheels off the pavement.  It always amazes me to see a 7 second run where the front wheels stay on the pavement, or only a couple of inches at most.  I had coil over shocks, adjustable ladder bars, and could adjust the car to leave level and hard against the line-loc.  Joe-JDC