Track guys in here please. Got a strange issue

[Duran]

Didnt do as well as expected at the track on Saturday but still managed to do a new best of 11.52@124.

Here is the issue.

2 months ago I tracked my Cobra with the following mods and times

Unported blower
2.8upper
2lb lower
intake
MAFIA
o/r x pipe
catback
tune

1.6 60ft
1/8 [email protected]
11.73@121

New mods and times

Lethal performance ported blower
Billetflow Single blade throttle body and pleunum
everything else the same except the tune of course.

1.6 sixty
1/8 [email protected] mph?????
11.52@124

As you can see my 1/8 mph has dropped but my 1/4 time is better. I was not to impressed with the new time because I was expecting more! I was lighter than before plus making more power...

My thoughts of possible things it could be are:
Stock clutch
belt slip
slightly more humid night than the last time I tracked her but still dont see how my mph at the 1/4mile is higher too with the more humid night...

Any more thoughts and suggestions would be great. :beer:

Here is a short vid of the run. The camera guy did not get me running through the traps but hey..

[ame=http://vimeo.com/4930102]Untitled on Vimeo[/ame]

 

[Duran]

Up

 

[MaximumVelocity]

Less wheelspin accounts for the lower MPH and ET at the 1/8th. Then power comes on down the track giving you higher MPH and lower ET at the big end.

 

[03slobra2]

Less wheelspin accounts for the lower MPH and ET at the 1/8th. Then power comes on down the track giving you higher MPH and lower ET at the big end.

+1 he is absolutely correct!!!! Good run and impressive shifting!!!

What are you launching at? It looked like it didn't spin so you could try to launch higher RPM and get just a touch of spin but nto much and you will see another small drop!!!

 

[Duran]

+1 he is absolutely correct!!!! Good run and impressive shifting!!!

What are you launching at? It looked like it didn't spin so you could try to launch higher RPM and get just a touch of spin but nto much and you will see another small drop!!!

I can see a few mph drop with the tires spinning compared to just dead hooking but I can almost say my higher mph 1/8 run a few months ago compared to this weekend in regards to the launch was almost identical. Both times I can say she just grabbed and took off...

Lets just look at the 1/8 time and mph now and tell me if my ported eaton Cobra should be trapping this? Ported blowers trap alot higher in the 1/8 usually high 90's right.?! Low 90mph 1/8 seems very odd to me! Compare me to others and you will see what I am talking about.

Here are a few
http://www.svtperformance.com/forums/time-slip-bar-42/595500-ported-cobra-1-8th-times.html

This guy here if you look at 1 of his slips has a 7.4@99mph 1/8 time with only a upper only. If I trapped 96-97mph unported the last time at the track wouldnt I trap higher with more power?
http://www.svtperformance.com/forums/time-slip-bar-42/552347-npb-friends-ported-eaton-04-cobra.html

 

[Posi]

Almost seems like the 1/8th mph was a mistake by the timers. Go back and prove it was.

 

[96stanggt]

Like Brian said the timers at the track could have very well made a mistake. I've had a few crazy slips here and there. Another option is what was the DA on both track days? The stock clutch may have slipped a bit in the lower gears killing some ET and MPH.

 

[Duran]

Almost seems like the 1/8th mph was a mistake by the timers. Go back and prove it was.

I like your way of thinking!! Or maybe I should send my blower to you!!!???

 

[94Gt5.0]

#1. What camera is that, it takes STUPID clear videos! Nice!

Like others said, if ya hooked it knocks off some mph.

I had something simila happen to me. One run my slip read 7.2@98(what i normally run). Next run it said 7.2@103, and I only ran .1 quicker(in the 1/4), with the same exact mph, which you would think that the extra 5mph from the 1/8th would carry over to the 1/4. Im leaning towards a faulty reading, which may also be your case. Try it again, and see what happens!!

 

[Duran]

#1. What camera is that, it takes STUPID clear videos! Nice!

Like others said, if ya hooked it knocks off some mph.

I had something simila happen to me. One run my slip read 7.2@98(what i normally run). Next run it said 7.2@103, and I only ran .1 quicker(in the 1/4), with the same exact mph, which you would think that the extra 5mph from the 1/8th would carry over to the 1/4. Im leaning towards a faulty reading, which may also be your case. Try it again, and see what happens!!

Thats interesting. Never thought the track could make mistakes. Its funny you guys mention this because I was talking to a track official that night about the track and he mentioned they remove the tree, sensors all the way down the track and even the time boards because of lightning... If they can be removed they could be put together wrong or different than before.

In regards of the camera. I dont know the guy who took the vid. I was impressed in the H/D vid too! Glad they got me for a second but wished they could have gotten me running through the traps on that run. Oh well.

 

[Posi]

I like your way of thinking!! Or maybe I should send my blower to you!!!???

I would assume Lethal and whoever did you port did a good job. You just had a bad track outing is all.

Like Kevin said check that Density Altitude. It makes a huge difference. Do a search on the net. Type in Density Altitude Calculator and the correct racing website will come up. You can then go and enter your exact track, date, and down to the hour and it will figure what you should've ran at sea level. Do that for both of the runs you posted and see how they compare. That could easily be part or most of it.


Then like the other guys said dead hooking will lose mph.

 

[Duran]

I would assume Lethal and whoever did you port did a good job. You just had a bad track outing is all.

Like Kevin said check that Density Altitude. It makes a huge difference. Do a search on the net. Type in Density Altitude Calculator and the correct racing website will come up. You can then go and enter your exact track, date, and down to the hour and it will figure what you should've ran at sea level. Do that for both of the runs you posted and see how they compare. That could easily be part or most of it.


Then like the other guys said dead hooking will lose mph.

Both nights were close.. Here is the data

04/09/09
Lonestar motorsports park
9:04pm

Temp 71 Humidity 78% Pressure 29.77 Track Elevation 263


Density Altitude: 1578 feet
Relative Density: 95.46 %

1/4 Mile time 11.73@121

Corrected ET and MPH

Stock and Mildly Modified Naturally Aspirated Engines
11.525 @ 123.201 MPH

Extensively Modified Naturally Aspirated Engines
11.618 @ 122.326 MPH

Extensively Modified Supercharged and Turbocharged Engines
11.665 @ 121.686 MPH




Ok this is what I got for this saturdays run.
Lonestar motorsports park in Sealy Texas
10:03pm 05/03/09

Temp 77 Humidity 78% Pressure 29.99 Track Elevation 263

Density Altitude: 1721 feet
Relative Density: 95.06 %


Correct your ET and MPH using the DA (Beta Testing)


Density Altitude:
feet above sea level


1/4 Mile Time 11.52@124

Corrected ET and MPH

Stock and Mildly Modified Naturally Aspirated Engines
11.297 @ 126.504 MPH

Extensively Modified Naturally Aspirated Engines
11.392 @ 125.554 MPH

Extensively Modified Supercharged and Turbocharged Engines
11.446 @ 124.809 MPH


Looks like I am close on both accounts..... Hope I did it right. This is the
website used.

DA Calculator - Density Altitude Calculator - DragTimes.com

 

[Brutal Metal]

There's a noticeable lag in time between shifts (you can hear it) speed shift that puppy or get THAT guy in your town that's an animal at the track and see what times he can get out of it!

 

[Duran]

There's a noticeable lag in time between shifts (you can hear it) speed shift that puppy or get THAT guy in your town that's an animal at the track and see what times he can get out of it!

Sure I need practice. Thats why I am going to track. Whats the point of having some one else drive my car? I want to be the one to put it in the 10's! The whole issue that stands is that my car trapped lower mph in the 1/8 this saturday with more mods and less weight than the last time around with more weight and less power... Same driver too.

 

[Venimus03]

How many passes did you make? Were all of your 1/8th mph the same, 92mph?

 

[Duran]

How many passes did you make? Were all of your 1/8th mph the same, 92mph?

Im glad you jumped in on this thread. I made 2 passes, the first pass being an 11.75@122 and the 1/8 on that one was a [email protected]....... Same crap..:shrug:

 

[KILRSVT]

man those are some good times good thing your at least in the 11's. i know a couple of guys with pulley cobra's that are in the 12's. your car can most def hit those low 11's maybe some more time at the track at trying out diffrent launching techniques.

 

[Duran]

man those are some good times good thing your at least in the 11's. i know a couple of guys with pulley cobra's that are in the 12's. your car can most def hit those low 11's maybe some more time at the track at trying out diffrent launching techniques.

Thanks.:thumbsup: If you want to be good at anything you must practice. I am trying to go to track as much as possible and get my shifting down so I can be ready for the winter. I am hoping to hit 10's with the ol eaton god willing. Want to join that 10 second club before the nitrous comes in or I sale the car... Which ever comes first.