Trying to put the power down without wheelie bars

Go down

Trying to put the power down without wheelie bars Empty Trying to put the power down without wheelie bars

Post  Dave De on October 16th 2019, 10:40 pm

Last Sunday at Milan Dragway it dead hooked and I couldnt recover it when it rolled from the right slick to the left while on the bumper. I thought the car was going to roll over on the side. So I lifted and down it came crashing hard and leaving the front end damaged including that nice pan that Lem sold me just 2 years ago.
A lady happened to take video of the car and sent it to me, it is grainy but I could see that the rear end had separated on the hit. I had my rear shocks set near maximum for extension to spread the hit out but it still stood on the rear end. The front shocks were 2 clicks from maximum and prior runs it felt like the tires were being plucked out of the beams without the suspension moving.

The car is 3250#, ladder rear that normally 60's in the 1.25 second time that runs 9.0's in the 1/4
tires are Hoosier 32 x 13.5 W's

Am I stupid thinking that this could be controlled without bars?
I'm going to bars and see that some are spring loaded and some are rigid. Also length varies.
Which type and how long for this wheelie crazy package?
After the bars are on do I set the shocks for maximum hit?

Video
https://youtu.be/2WBKJ_LJ-6c


Last edited by Dave De on October 16th 2019, 11:14 pm; edited 1 time in total (Reason for editing : added video)
Dave De
Dave De

Posts : 585
Join date : 2011-05-27
Location : Highland, MI

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  wickettoby1 on October 17th 2019, 12:01 am

Holy s**t, you were at Milan when they actually prepped the track😃😃😃
Joking aside sorry to hear about the damage from you’re “return to earth”.

wickettoby1

Posts : 196
Join date : 2016-02-02
Location : SE Michigan

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  wickettoby1 on October 17th 2019, 12:01 am

Double post

wickettoby1

Posts : 196
Join date : 2016-02-02
Location : SE Michigan

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  wickettoby1 on October 17th 2019, 12:03 am

.

wickettoby1

Posts : 196
Join date : 2016-02-02
Location : SE Michigan

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  DILLIGASDAVE on October 17th 2019, 5:54 am

Eh, ladder bars can get damn violent with decent at-launch power/torque numbers to work with. And the average off-the-shelf coil overs with standard valving installed might not be able to keep up and quickly become overwhelmed. Combine the two and boom....violent dead-hook happens and the car climbs the ring gear before you can react.

Or it could have just been unusually good track prep.

Either way you probably need to think about doing something/anything to generate some wheel-speed at the hit. That usually means slowing down the suspension's initial hit (using any number of methods) , or adding wheelie bars, or adding more power, or playing with slick air pressure.

Or keep the dead-hook & calming it back down with either an ignition box timing retard ramp, or use one of the Davis boxes.
DILLIGASDAVE
DILLIGASDAVE

Posts : 2237
Join date : 2009-08-08
Location : Texas. pronounced "texASS"

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  Dave De on October 17th 2019, 10:30 pm

Wheel speed on the hit. Tires are at 32.2 tall, the gear is only 3.70 and the first gear is 2.40. Some look for a multiple number 2.40x3.70=8.88
I was thinking to go a 3.50 gear to get it down to 8.44
Dave De
Dave De

Posts : 585
Join date : 2011-05-27
Location : Highland, MI

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  stanger68 on October 18th 2019, 12:23 am

What launch rpm? Trans brake? I’m far from a tuning guru but I would take the cheap route to start with to get an idea what the car will like. If you’re using a trans brake, swap it for a studder box and leave at a much lower rpm and let the converter soften the hit. Doing it this way you may have to adjust your reaction time though. This was recommended to me by a converter manufacturer for running foot brake with a lot of power.

I’m still trying to work the bugs out if the rest of the car but that method does keep the front end down.

Question is if you can drive it good enough Very Happy

stanger68

Posts : 332
Join date : 2015-12-05
Location : Birmingham, Al

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  stanger68 on October 18th 2019, 12:26 am

stanger68 wrote:What launch rpm? Trans brake? I’m far from a tuning guru but I would take the cheap route to start with to get an idea what the car will like. If you’re using a trans brake, swap it for a studder box and leave at a much lower rpm and let the converter soften the hit. Doing it this way you may have to adjust your reaction time though. This was recommended to me by a converter manufacturer for running foot brake with a lot of power.

I’m still trying to work the bugs out if the rest of the car but that method does keep the front end down.

Question is if you can drive it good enough Very Happy

You can do the same thing with a trans brake if you’re worried about breaking beams. just wire the two step in the same circuit as the brake

stanger68

Posts : 332
Join date : 2015-12-05
Location : Birmingham, Al

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  Dave De on October 18th 2019, 8:48 am

Broader Performance pro tree valve body. leaving off 3600 rpm 2 step with a converter flash at 4400 rpm. Trans brakes are consistent.
I know this package should have a glide but I just dont want to do that. I am thinking the 3.50 gear and pulling some timing may be best or just go bars.
Dave De
Dave De

Posts : 585
Join date : 2011-05-27
Location : Highland, MI

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  litshoot on October 23rd 2019, 12:34 pm

2nd gear start an option, maybe lower launch rpm a couple hundred. If it helps then get converter rebuilt

litshoot

Posts : 79
Join date : 2015-09-11
Location : Sfl

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  Dave De on October 23rd 2019, 6:31 pm

litshoot wrote:2nd gear start an option, maybe lower launch rpm a couple hundred.  If it helps then get converter rebuilt

Leaving in second with a 1.40 ratio wont cut it. Also the brake wont work in second gear.

I am going to a lower number ratio somewhere between 3.50 and 3.65 and use bars.
Will that help with instantaneous wheel speed?
Dave De
Dave De

Posts : 585
Join date : 2011-05-27
Location : Highland, MI

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  DILLIGASDAVE on October 25th 2019, 5:10 am

Dave De wrote:.....I am going to a lower number ratio somewhere between 3.50 and 3.65 and use bars. Will that help with instantaneous wheel speed?

If the car is already setup for and/or has a set of wheelie bars you could save a few bucks and test the bars first before spending money on a gear change. You could test lowering the wheelie bar height pass-to-pass until the car goes from trying to yank the nose up-out of the beams to flat-out spinning the slicks. Then raise the W/B height back up a little and fine tune from there with air pressure changes.
DILLIGASDAVE
DILLIGASDAVE

Posts : 2237
Join date : 2009-08-08
Location : Texas. pronounced "texASS"

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  Dave De on October 25th 2019, 11:29 pm

I like your plan. I'll get the front end fixed then work on the bars. Should the bars be spring loaded or rigid?
Dave De
Dave De

Posts : 585
Join date : 2011-05-27
Location : Highland, MI

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  DILLIGASDAVE on October 26th 2019, 6:29 am

Dave De wrote:.........Should the bars be spring loaded or rigid?

Meh, kinda depends on a few things. In a lot of situations if the w/bars are short (or are the older design with aluminum strip for the lower "bars") being spring loaded can be a benefit. But if the w/bars are long and made of all thin wall 'moly tubing (and doesn't use aluminum strip lowers) then they usually aren't spring loaded because the w/bar it's self flexes under load and in effect acts as the "spring".
DILLIGASDAVE
DILLIGASDAVE

Posts : 2237
Join date : 2009-08-08
Location : Texas. pronounced "texASS"

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  snuff98 on October 26th 2019, 2:53 pm

I run a ladder bar also, tightening the front shock setting, limiting front suspension travel, and even changing front and rear ride height can help with wheel stand. My car would not wheel stand unless the track was real good. I put wheelie bars and the 60' picked up and got deadly consistent 1.17 pass after pass. It never drove that well before the bars.

snuff98

Posts : 187
Join date : 2016-08-04
Age : 49
Location : Hessmer Louisiana

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  STR-LGL-70 on October 27th 2019, 8:48 am

I'm getting ready to go down the same path, ladder bars with C-6 and I think we are both making similar power- how much set back does your engine have? Also been reading up on ladder bars and I saw somewhere where sprung (wheelie)bars were recommended with ladder bars.

Sheldon G
STR-LGL-70
STR-LGL-70

Posts : 214
Join date : 2009-08-06
Age : 56
Location : Daytona FL

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  DILLIGASDAVE on October 27th 2019, 9:25 am

I guess another "simple/easy" option is to just hanging some given amount of weight ballast out on the nose and test to see what happens. The farther you can hang the weight ballast out on the front/nose of the car the greater the effect it will have (and do it with less total weight).

Years ago while working a set of scales on a full chassis car we played around with the placement of a small 5lb ballast puck. It is amazing how much effect just 5lbs of ballast has on the front/rear weight percentages as you move it farther & farther out on the nose of a car.
DILLIGASDAVE
DILLIGASDAVE

Posts : 2237
Join date : 2009-08-08
Location : Texas. pronounced "texASS"

Back to top Go down

Trying to put the power down without wheelie bars Empty Re: Trying to put the power down without wheelie bars

Post  snuff98 on October 27th 2019, 1:47 pm

I run 72" solid wheelie bars with ladder bars, works very well for me.

snuff98

Posts : 187
Join date : 2016-08-04
Age : 49
Location : Hessmer Louisiana

Back to top Go down

Back to top


 
Permissions in this forum:
You cannot reply to topics in this forum