Launch Help...video included

[nitrobob]

Looking for help or suggestions on set-up to get a better weight transfer.

This video is of car launching on the 2step at 4000 rpm. Current set-up is as follows

Strange front Single Adj set at 3 clicks from soft
Strange rear Single Adj set at 5 clicks from soft
M/T ET Drag 28x10.5x15 stiff wall 13 PSI
BMR relo,LCA bottom hole,PHB
3650 with 4.10..

Was able to get a 1.7 60ft here but can't seem to get any lower then that. Seems the car gets no wheel spin from the hit but after the weight transfers forward seems to bog ... I'm wanting to keep the weight transfer back at least to the 60 before it settles.

Any ideas or suggestions???

TFTH

 

[skwerl]

I had the same issue with my Bullitt bogging right off the line no matter how hard I launched. Became frustrating to the point I gave up on drag racing except on perfect weather nights (better DA).

 

[AlbertD]

Have you tried launching higher? What is your trap speed?

On the GT I had a very similar setup as you do now, but I was rocking 4.56s and launching at 6k with the 2 step. I pulled consistent 1.51-1.52s this way.

My trap was between 114-116 so I had room to accommodate the lower gearing.

 

[nitrobob]

I ran 96mph on that pass..1/8th mile

 

[nitrobob]

Have you tried launching higher? What is your trap speed?

On the GT I had a very similar setup as you do now, but I was rocking 4.56s and launching at 6k with the 2 step. I pulled consistent 1.51-1.52s this way.

My trap was between 114-116 so I had room to accommodate the lower gearing.

4000 is the highest I have gone. Not sure how many 5500 launches the stock clutch can handle...

This pass trapped at 96mph...1/8th mile

 

[lindertw]

what springs are you running? setup on my '05:

- cobra jet springs (m-5300-q)
- strange single adj front struts set to full soft
- strange single adj rear shocks set to +3 clicks from full soft
- LCA set to middle hole on BMR reloc brackets
- UCA set to upper hole on UCA mount (stock position)
- pinion angle set to ~ -2.5deg
- 17" oem wheel with M/T et street bias ply set to 18psi
- 4.10 gears w/eaton truetrac diff
- stock 3650/clutch/shifter
- 302 rwhp, 3600lbs
- side stepping the clutch @ 4500-6000k rpm

best 60' was 1.652, and I'm certain there's more in it... 15" rt-s rear wheels are next on the menu, and probably d/a rear shocks too.

in this vid (with the heavy front wheels) the nose stays up almost through the 60' blocks:

 

[nitrobob]

what springs are you running?


BMR Springs front and rear...

I was thinking adjust the fronts to full soft and leaving the rear shocks where there at.

Also thinking that the clutch may not holding the power and slipping and letting the car nose over but it launches hard.

 

[AlbertD]

I would launch at 5 and see how she does. If the 60 improves, try 6. I understand what you are saying about the stock clutch. I wouldn't trust it either. I ran an Exedy Mach 400, that thing endured two years of numerous 6k drops no problem.


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[dysan]

You need to tighten the compression some how on the front so it doesn't drop as fast. That is why I decided to go with the lakewood 90/10's on my car since the adjustment on the Strange front struts does more for the rebound/extension rather than the compression. Maybe a different front spring may help but I can't say for sure.

Strange sent me the chart on the struts...here is a picture of it.

 

[roberts]

nitro where u from in missouri??

 

[MGT2009]

I'm having the same issue. Tires hook but then falls right on its face.

My setup:
FRPP K springs
FRPP front non-adjustable shocks
BMR UCA on upper hole
BMR LCA on middle whole of steeda brackets
Viking dbl adjustable - 4 compression, 12 rebound
4.10 gears
m&h 275/50r17 at 14psi

launching at 5k, all i can muster is a 1.84 60 foot. Literally just falls on its face.

This is causing me to not get past 8.4's in the 1/8th and its driving me nuts.

Next outing i'm gonna try the LCA in the lowest whole and maybe more compression. My thinking is its transfering weight to fast which causes the car to bounce back. Hopefully more compression will slow it down.

Any other advice?

 

[CPRsm]

Launching and bogging is a good thing. It's easier to lessen traction lol
Go up in the back w the lca's. That will hit the tires softer hopefully gaining tire speed to let the tires spin a bit. Either that or up the rpm again. Too much traction and not enough power to accelerate the car is causing the bog.

 

[DVEST8R]

move the lca to the middle hole and play with air pressure some. I think your air pressure is a tad low. 14.5- 15 psi worked well for me on bias plys

 

[fdjizm]

Shit I wish I had a too much traction problem.
Can't wait to get to the track with my adjustables though.
Last time my issue was the tire pressure was too low at 14 psi cold (Hoosier QTP), coupled with my anti-squat it was slamming the rim into the ground and bouncing back up and unloading.

 

[BMR Tech]

BMR parts doing their job. I likey.

OP, raise the LCA up to the top hole of the bracket. See what happens.

If you keep it as is, you simply need to raise the RPM until it doesnt bog. It will either do what you want, or it will blow the tires off.

Also, stiffen the front and rears a little. Try 7 rear and 5 front.

Let us know.

 

[nitrobob]

Thanks for all the ideas...My next outing I will try the top hole on the relo brackets and adjust tire pressure to 15 psi along with adjusting the front and rears to 7R and 5 F.. Again launching at 4000 rpm to see if there is any change.

Again, thanks for all the input..

 

[nitrobob]

nitro where u from in missouri??

Perryville

 

[roberts]

Perryville

We will have to meet man I'm in Bonne terre. Going to try and make the august 2 meet in perry ville I believe is where it is


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[Sharad]

Yeah, I was going to recommend setting the rear shocks to 8 and feeding it 5000+ RPMs.