Could My Exhaust be Hurting my 1/4 times?

[Fahrenheit]

Went to the track on Saturday, overcast and cool, had a 5-10 mph head wind. My first run was a 13.3 @ 104, 8.5 @ 1/8th, 2.0 60', and ran this consistantly, only got 1 13.2 run @ 102, had 102 mph trap times all night. It didnt matter if I stalled the truck up at the line or just mashed the gas. I let some tire pressure out by 2 lbs each run starting off at 20 psi. The truck took off great each time, but Im still getting use to the feel of the stall.

NOW, I did notice that the shift from 1-2 was around 6000-6200, but the 2-3 was 3500. The truck was in tow/haul the whole time except one time when I changed the tune to mid octane on the SCT.

I do have the MBRP exhaust, it goes from the stock headers to the JMB 3" cat-less mid pipes, back to 2 1/2" that connect to the MBRP exhaust and 4" out the rest of the way.

I also switched to the SCT from the DC computer, I need to get with Torrie to see what all mods need to be inputed into the tuner, Im pretty sure I didnt mention the BBK throttle body, torque converter, and MBRP exhaust because all of these things were in the works when I purchased the tuner.

I was also thinking of putting an X-pipe on to see if I get some HP back, and to quiet the exhaust down...........

If anyone has any suggestions, please let me know. Im pretty disappointed that I didnt crack 12's after all the hard work I put into the truck in the past few months.

 

[TNVIPER]

The low 13s are great times for your mod level....but the 3500 rpm 2-3 shift is definitely low and surely cost you time...call Torrie and confess your mods.....

 

[Fahrenheit]

Before all of the new changes, I was running consistant 13.1 -13.0 @ 104/5 so I have lost .2 -.3 somewhere

 

[TNVIPER]

The 3500rpm shift is where I would start...that has to bog you bad...

 

[WOT]

3500rpm 2-3? That is bizzare. Seems like you have a spike in your govenror pressure WOT curve. You could manually shift and see what your qtr mile times are. Should improve a bit. I would get the 2-3 shift fixed though.

 

[Fahrenheit]

I did it before when I was missing the brace on the transmission that held the downshift cable, and I did a 13.5

 

[rottenronnie]

Went to the track on Saturday, overcast and cool, had a 5-10 mph head wind. My first run was a 13.3 @ 104, 8.5 @ 1/8th, 2.0 60', and ran this consistantly, only got 1 13.2 run @ 102, had 102 mph trap times all night. It didnt matter if I stalled the truck up at the line or just mashed the gas. I let some tire pressure out by 2 lbs each run starting off at 20 psi. The truck took off great each time, but Im still getting use to the feel of the stall.

Have a look at the link below as "overcast and cool" doesn't mean it was a good air day at the track. Maybe yes, maybe not..

Pay more attention to your m.p.h. than your e.t. as that is a more accurate indicator of power.
Any kind of head wind is going to act on the 32+ sq. ft. of frontal area on the SRT-10; the wide front tires don't help either.

Plug the track you were racing at into this DA Calculator, the date and time of your runs and then press "Get Weather Data" .
When it gives you that data, plug the Temperature, Humidity and Pressure into the boxes, then press "Calculate DA".
That will tell you how far off of sea-level you were.

It makes and enormous difference. I've seen a FULL SECOND drop off of vehicles racing where I am then racing at sea-level.

http://www.dragtimes.com/da-density-altitude-calculator.php

See what it spits out and let us know..

Ronnie