new best all motor but still working out some issues.

[xtweakerx]

Ok got cams and delete plates recently before cams and delete plates previous best was 12.66 current new best is 12.37

So I've been having issues with traction since I got the cams and delete plates, being consistent in the 60foot and not getting squrily in the top end.

DA was 943 for this pass:
60: 1.65
330: 5.02
1/8: 7.85
mph: 87.13
1000: 10.30
1/4: 12.37
mph: 108.77

Once I hit 3rd gear, from 3rd gear to 4th on this pass it was getting squirly on the top end so I know I lost some there.

I was running 13psi in the rears 27x10.5x15 et streets bias ply and 45 psi in the fronts et front 26x4.5x15.

I tried 14psi in the rears but I spun the tires off hard to 1.85 60foot

Then I went back to 13psi in the rears and again spun to 1.85 60foot to a 12.60. Now I'm going to head out to a test n tune and try to dial this in since I was at a bracket race trying to get this sucker to dial in.. Right now I'm leaning towards that I was leaving a bit too hard on the 1.85 passes and/or my burn outs may have been to long. It was heating up as the day went on. So i'll be looking forward to most likely next week trying to get some test n tune sessions in to dial in it, any advice would be helpful.

Full list of mods:

Brisk Spark Plugs
Hurst Line-Locks
5 Speed Manual
Steeda Delete Plates
Ford Racing Hot Rod Cams
Ford 4:10 Rear-end Gears
Hurst Billet Short Shifter
Custom BBR Dyno Tune
Washer Fluid Tank Removed
UPR Sway Bar Removal Kit
Cobra Jet Springs
Rear Seat Delete Kit
Steeda Under Drive Pullies
Steeda Upper & Lower Control Arms
BBR Off-Road X-Pipe
Flowmaster Axle-back Exhaust
C&L "Racer" Cold Air Intake
Axle-Exchange Aluminum Driveshaft
MT ET Front Tires 26 x 4.5 x 15
MT ET Street Tires 27 x 10.5 x 15
Summit 541 Series Wheels - 15x4 (fronts) 15x8 (rears)

Photo of the car but in that photo that day i went 12.40 w/ 1.72 60foot.

 

[SpartaPerformance]

You're shifting into 4th? Sounds like you need some more RPM or a taller tire.

 

[xtweakerx]

Dude i have 4.10 gears you have to shift into 4th.... I shift at 6500 rpm..


this forum is Officially dead to me...

 

[SpartaPerformance]

It could be dead to you but you still need a gear,RPM,tire combo so you pass the traps at the end of 3rd.

 

['08GTcaRED]

What RPM are you launching at tweaker? If you are still reading this dead forum that is...

 

[Five Oh Brian]

It could be dead to you but you still need a gear,RPM,tire combo so you pass the traps at the end of 3rd.

What's so important about going through the traps in 3rd gear? I, too, have 4.10's (quite a popular gear choice for many of us, you might have noticed) and I run a 275/40/17 BFG drag radial (a popularly sized drag radial) and I'm going through the traps in 5th gear (4th isn't even enough). Not ideal to be engaging overdrive, I know, but I get my best ET's and trap speed by doing so.

 

[SpartaPerformance]

Because you're in your peak HP range, in 4th and especially 5th you're not making any power. It's not ideal. Tweaker doesn't have a super charger like you but he runs almost identical E.T.'s, he shifts into 4th only as compared to your 5th he's using more of his RPM band. If he had the proper height tire to get more RPM and stay in 3rd he might be able to cut a couple more tenths off his E.T., that also may be his high speed tire "waggle" with the reduction in RPM he's putting less torque to the wheels its almost like lifting.

 

[Marc S]

Sorry Sparta, your wrong on this one. With a properly set up manual trans car, your best ET's will come from crossing the stripe in 1:1 and the engine just past redline. You will have more torque multiplication at the launch with say 4.10's over 3.55's. Every successful stock eliminator car with a manual transmission crosses the traps in 4th gear not 3rd.

With your explanation, you might as well gear your car so you never have to shift and keep the thing in 1st gear all the way down the 1/4.

I'm not trying to be a jerk. However, I have held many records in NHRA stock eliminator with a 4speed manual. I have been wrong before, not this time though.

 

[SpartaPerformance]

...stay in 3rd he might be able to cut a couple more tenths...

You're correct when you say passing the traps at the end of 1:1 gear but, to me the way I read his post he's just shifting into 4th a little before he's passing the traps.

 

[bynumj]

What is your redline set at?
What is your current 1/4 mile RPM at?

I think you need shorter tires and more gear to dial it in. I am assuming that you do not want to say NA and tune from here.

Here are my calculations:
Currently with the 27" diameter tire and 108MPH at the 1/4, you should be turning 5610RPM. You are leaving a bunch of power on the table by not getting the RPM up at the trap. Here are your current 4.10 gear vs. MPH @ 6250:

2nd - 61.3mph
3rd - 92.9mph
4th - 122.6mph
and at 108mph in 4th - 5506rpm

At your shift from 3rd to 4th you are dropping the motor down to 4741rpm. This will drop you down out of your power band for a longer period of time.

Recommendations:
1) Drop down to a 26x10.5x15 tire:
Calculated results:
Here are your calculated 4.10 gear vs. MPH @ 6250:
2nd – 59.2mph
3rd – 89.8mph
4th – 118.5mph
and at 108mph in 4th - 5696rpm

2) Drop down to a 26x10.5x15 tire and go with 4.30 gears:
Calculated results:
Here are your calculated 4.30 gear vs. MPH @ 6250:
2nd – 56.5mph
3rd – 85.6mph
4th – 113.0mph
and at 108mph in 4th - 5974rpm

3) Keep the 27x10.5x15 tire and go with 4.56 gears:
Calculated results:
Here are your calculated 4.56 gear vs. MPH @ 6250:
2nd – 55.1mph
3rd – 83.5mph
4th – 110.2mph
and at 108mph in 4th – 6124rpm

I have a gear chart newly posted in the 2005-2011 section that will help with the calculations. Again, these are based on the mathematical calculations but should be fairly accurate to real world conditions.