Losing time at the drags

[capercode]

Hi All,

03 Cobra, 2.76 upper, stock lower, bassanni exhaust with cats. Turned 12.1 @ 116.7 with street radials. We put a set of Mickey Thompsons on and a Metco belt snubber and ran a best of 12.4 @ 108.3 with a 1.82 60'. Any thoughts on why it slowed down? I'm baffled. I checked the inrecooler pump and its working. Tires were @ 18lbs and hooked much better then the street radials.

 

[01yellercobra]

What was the 60ft on the first run? Were the changes made on the same day?

 

[railroad]

Might compare roll out on the rear tires, circumference.

 

[Deceptive]

Temp/humidity/launch RPM?


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[LS WUT]

What size tires are you running? If you got 27.5 tall tires now it could slow you down a little.

 

[robvas]

Did you make 5lbs less boost by any chance on the slower run?

 

[capercode]

What was the 60ft on the first run? Were the changes made on the same day?

60' on the higher end mph were, 1.98 & 2.01. The slicks defintely helped the 60' but we lost the mph. Has me baffled. The runs were 2 weeks apart and the slower times were at 90 F

 

[capercode]

Did you make 5lbs less boost by any chance on the slower run?

Stock gauge so I can't honestly say.

 

[capercode]

What size tires are you running? If you got 27.5 tall tires now it could slow you down a little.

The slicks are the same size as the stock street radials. 2.75x40zr 17

 

[hatchke]

Losing 8mph with a similar ET is pretty significant. I was going to ask something similar to @robvas and about belt slip, etc.

 

[LS WUT]

That’s significant for sure. I’d check into belt slip as well, depending where you live. Was the DA better?

 

[LS WUT]

I know in Florida it’s ****ing brutal. You lose some serious time.

 

[DSG2003Mach1]

What were temps when you made the quicker passes? IAT2 can be a real SOB

 

[CobraBob]

60' on the higher end mph were, 1.98 & 2.01. The slicks defintely helped the 60' but we lost the mph. Has me baffled. The runs were 2 weeks apart and the slower times were at 90 F

What was the temperature on the 12.1 @ 116.7 run?

 

[capercode]

Temp/humidity/launch RPM?


Sent from my iPhone using svtperformance.com

Temp 90 humidity 82% launch RPM 4000

 

[capercode]

What was the 60ft on the first run? Were the changes made on the same day?

2.12 60'. the second set of runs was 2 weeks later. Bradenton Fl 90° Humidity 82°

 

[5.0 Hatch]

8mph is roughly 80hp. There has to be something up other than tire and temperature.

 

[capercode]

What was the temperature on the 12.1 @ 116.7 run?

78°

 

[Deceptive]

78°

Do you have logs of IAT1 and IAT2 temps on both runs?

I suspect temps are your issues when looking at things on the surface.

According to your post, the only difference between run 1 and 2 is tires and weather.

Run 1 had better temps and I imagine better humidity and DA.

Run 2 looks like weather was Jared’s Applebees bartender’s bootyhole in a Louisiana in summer in nature.


Does two women scissoring sound like an armpit farting contest?

 

[capercode]

Losing 8mph with a similar ET is pretty significant. I was going to ask something similar to @robvas and about belt slip, etc.

Belt slip was

That’s significant for sure. I’d check into belt slip as well, depending where you live. Was the DA better?

Take the belt snubber off?