Some basic simple questions

[JrFuel Hayden]

Curly, you said you have a data computer, what driveshaft speed is the highest when your spinning the tires before it hooks up ?
What height do you set your WB, and is that with you in the car, and what tire pressure, because the tires will squat when you get in the car and that will lower your WB.
Is your WB stiff and what length ? if your WB is too stiff when your front starts to come up it will hit hard and unload the slicks, causing spin, at least try adding another 20 on the nose.
I'm not surprised you might be getting bounce because of the 6.8 lb of pressure, which explains your experince of running the lower pressure.
You could also have too much tire, it may have worked good on your other car, but your 14x32 could be dead hooking, and pulling your engine down below your HP range and much harder to get "up on the tire" because of less HP. Are your M/T a soft compound tire, also makes it too easy to dead hook.
My JrFuel car at 1435 lbs with driver, gets to 2300-2500 rpm drive shaft speed about .3 into run before it hooks up and my RacePak curve shows a "J" hook where it is spinning to 2300, the hooks up and is confirmed by my "G" meter graph. We run mostly 31x12x15 Goodyear that are very light weight [ less rotaing weight] at 22.6 lbs per unmounted tire. Hayden wheels special orders them.
You have found what I have found , lower tire pressure will increase tire speed, and when I'm looking for more traction [ less tire speed] I increase tire pressure on my 12" tires. i run between 5 3/4 to 6 1/2 pressure. I launch at 6200-6600 rpm to again "get up on the tire"  and keep it spinning so it does not pull the motor down. We run 1.01 to 1.05 sixty foot times, and allot of 7.0's at 185-189 mph. on injected alky with an all iron 399 ci SBC.
One thing you might want to check is lift the front-end up, while you are in the drivers seat , to see where it hits your WB. You may already be on the bar. I put chalk on the WB wheel and check what kind of tracks it leaves, most of the time on my car it leave about one to 1.5 foot track, then leaves another short one, telling me it's hitting the WB then spinning some and if it does not leave a 3'rd track, means it's "up on the tire" after that.
I hope this info helps, and you can call me anytime 805-444-4489 on my cell.
Jon

[Frontenginedragsters]

Jon:
 Thanks for posting this information.
It's helpful to more people than just the guy asking the question.
Matt Shaff

[Curly1]

I am going from memory here but right at the hit the driveshaft RPM spikes up to 1800 and then dropped to 1400 RPM from there it climbs as speed goes up. My altered never did that. It would go up then maybe flatten out for just a split second and then start climbing again.

[Curly1]

Okay, I looked at the data logger. At .34 into the run driveshaft RPM was 1859 and at .45 in the run it had dropped to 1459. My altered never slipped any.

[rooman]

Sounds like it is dead hooking if it pulls the driveshaft speed down that much.

Roo

[Curly1]

This is data logger of good run in my altered earlier this year. Note the driveshaft RPM.
https://imgur.com/USCFQjX

[Curly1]

Now here is one of the first runs on dragster with same air pressure 6.8. I think it was bouncing and spinning.
https://imgur.com/OgapcsO

[Curly1]

I thought the car was bouncing and spinning on the other run so I dropped the air pressure to 5.8 and it appears that it had one little bounce and spin.  I am going to be racing on Saturday and we should be able to get some video to hopefully verify what is going and learn which way to go from there. So any thoughts or help here is appreciated.  I do not think it is dead hooking here.
https://imgur.com/QEcIQXx

[Roger]

Have you tried raising the pressure? Every car will react differently depending on the combination and while lowering the pressure might help increase tire speed and minimize dead hooking, raising the pressure will also result in increased tire seed and minimize dead hook. Might be worth a try.

[Curly1]

I have not tried raising air pressure but I started at 6.8 and when I lowered it to 5.8 it was better so I think it was heading in the right direction. I should be able to get some video tomorrow and that may give me some idea of what to do. Right now I am not happy with the performance. I went to the dragster because I thought it would be much more forgiving and faster than the altered. So far it is not and the altered was much easier to load and unload and more fun to drive to.

[Curly1]

Second race in and it was good for Number 1 Qualifier and a runner up finish but it was not with out some issues and drama.  Still spinning at the hit too much and bouncing in the shut down.  My plan next time is to raise wheelie bar and tire pressure a little more. I may experiment with raising launch RPM to hit the tires harder and keep the chassis loaded. Right now I am just not sure what is the best way to get this thing handling better and down the track every time and with out drama.
The spin is about .3 into the run and drive shaft RPM spikes up to 1800 RPM and then drops to 1400 and from there it climbs normally and as speed increases.
When I built it I thought the full size battery up in the very nose would help performance, but now I am thinking it is too much up front and may be limiting weight transfer on the launch? Car weighs 1730 and has 389 on the front. I could save 35 Lbs by going to a Lithium battery up front if I have to. What does have to happen is to get this thing working where I do not have any aborted runs unless track is just not there.

I am looking for any help and suggestions here.

[wideopen231]

why spend money on lithium.Just remount battery back at engine.If I remember you had issue with spinning motor faster and 12' less wire should help that although you seem to have corrected it>again if I am thinking about your deal and not someone else's. Not that all cars are same and all rules fit every car. Park's told me I needed 300# on front. I am sure the guys with more FED experience will correct me if wrong.  I don't really believe that is issue since most of the time keeping front end down is more of issue. IMO do one or other.Wheelie bar or move weight,not both. Old rule never do two things at same time,if it works.Which one was it. I would put jack under front end pickup till bar hits good and adjust from there. I am firm believer in leaving hard so my vote for the 1/2 cent its worth is for more rpm first then others.

[wideopen231]

whats #1 q = et________/MPH________

[Curly1]

I am going to try raising tire pressure, launch RPM and wheelie bar first. I am not going to Lithiium battery unless I have to and get video that confirms what it is doing. Right now I just am not sure what it is doing or how to fix it.

[AWAG]

Why does everyone say to put a jack under the front end to see how high it is when the wheelie bar hits? The front end gets picked up by the pinion trying to climb ring gear. So wouldn't the front of the motor be your leverage point? Shouldn't you put the jack there so you can take into account the chassis flex? I had an old fed that was a late 60's 186" car. When I put a wheelie bar on it I first set it at 3". That car wouldn't do anything but sit there on that starting line and just spin. Front tires never raised a bit.  What was happening was with that narrow chassis it had a lot of flex in it. Once I put 5" under the wheel it started behaving. This was only with a mild sbc