Jeep TrackHawk Forum banner
1 - 10 of 10 Posts

·
Registered
Joined
·
412 Posts
Discussion Starter · #1 ·
Living in N. Texas, its hot most of the year, and since i bought my TH in May, I haven't had any opportunities to drive the vehicle with temps below 70^.

Today was the first. My typical 0-60 times (going off on-board computer only) have been 3.4-3.5 in 85+^ heat. Just made one pull today... sunny out, so concrete is warm, 65^F air (its not humid, so DA is good). Footbrake to ~1800rpm... 3.2 seconds. 1.58 60' time. :) Had a little tirespin at launch, but obviously not enough to hurt the short time. This particular road where I do my pulls is not long enough for a full 1/8th or 1/4, but it is good concrete and flat.

I will make a pull or two when it drops below 50^F... but it will be interesting to see if I can equal/better the times. My guess is more power may create more tirespin + colder concrete/tires may not allow quality traction.

This thing is just too much fun.
 

·
Registered
Joined
·
97 Posts
Nice! These things love cool weather for sure.

Not to throw shade on your accomplishment but I don't have much faith in the factory timers anymore. The 60ft on the slip was a 1.46, 0-60 was probably 2 seconds, 1/8th time is almost an exact match to the slip, 1/8th mph is about 70mph too fast however lol. This is one of our D4X packages with a little gas on it.

If we get a TH to 60 in 1.08 it's probably a ProBoostTH running the in big leagues in PDRA, lol.
 

Attachments

  • Like
Reactions: WA 2 FST

·
Registered
Joined
·
412 Posts
Discussion Starter · #3 · (Edited)
I trust your expertise, since you guys race these all the time. I have no clue whether it is accurate next to a dragstrip timer (in theory, I'd think the strip timer would be quicker, given you get 12" of rollout or so), but I would hope/expect it would be close in relation to itself on the same vehicle, same road conditions, etc. IOW, two vehicles running side by side might show different on-board times, even if they are side-by-side the entire run.

The 1/8 mile trap speeds on these things are crazy off quite often... I've seen guys with stockers running 150mph on the on-board 1/8 mile trap, but only 117mph through the 1/4 mile... same pull. LOL. So yeah, I take that with a grain of salt, too. I'd also imagine on a wildly modded one like your D4X, that will skew the on-board accelerometer more than it would on a stock/near stock one.

On another note, what is the turnaround if I next-day my PCM to you for an unlock and tune on a stock TH? This is my DD, so I can't afford much downtime. I'm not ready for pulleys/injectors yet. ;)
 

·
Registered
Joined
·
97 Posts
I won't argue with some of the numbers shown. I'd say they have it half way figured out ;)

We can get it done pretty quick! Which package were you thinking? Let's take it to PM if that's ok.
 

·
Registered
Joined
·
111 Posts
I trust your expertise, since you guys race these all the time. I have no clue whether it is accurate next to a dragstrip timer (in theory, I'd think the strip timer would be quicker, given you get 12" of rollout or so), but I would hope/expect it would be close in relation to itself on the same vehicle, same road conditions, etc. IOW, two vehicles running side by side might show different on-board times, even if they are side-by-side the entire run.

The 1/8 mile trap speeds on these things are crazy off quite often... I've seen guys with stockers running 150mph on the on-board 1/8 mile trap, but only 117mph through the 1/4 mile... same pull. LOL. So yeah, I take that with a grain of salt, too. I'd also imagine on a wildly modded one like your D4X, that will skew the on-board accelerometer more than it would on a stock/near stock one.

On another note, what is the turnaround if I next-day my PCM to you for an unlock and tune on a stock TH? This is my DD, so I can't afford much downtime. I'm not ready for pulleys/injectors yet. /forum/images/smilies/wink.gif
On the 1/8th mike runs I also have noticed a speed of 150. I’m starting to wonder if FCA screwed up when they programmed the computers and it is actually showing kilometers per hour rather than miles per hour on the 1/8th mile program. 150kmh is actually about 93mph. Just a thought.
 

·
Registered
Joined
·
412 Posts
Discussion Starter · #7 ·
3.2 is eye candy - and you can tell it’s faster than 3.4. Enjoy!
I agree... it is a noticeable difference with the cooler air. Ran at 48^F yesterday and got a 3.1. Again, all tests are done on the exact same road. If it ran 3.4-3.5 in 85-90^F heat, maybe the timer isn't perfectly accurate and I didn't run a 3.1... but all I know is, as you said, it is definitely quicker than the 3.4-3.5 I was running in hotter temps. I wish this road was longer because it is very close to home, perfectly flat, and quality concrete. I could probably run out a full 1/8th mile, but at that point I would be going well over 2x the speed limit and have to slam the brakes very hard.
 

·
Registered
Joined
·
5 Posts
Sweet! Please share your spot, I live in Addison and have been looking for a spot to put my TH in launch mode. Happy to hear 0 to 60 is around 3.0 seconds. I figured estimated 3.5 was beatable due to the horsepower to weight ratio of the TH..
 

·
Registered
Joined
·
55 Posts
lol. We've got one of those roads here in north NJ near my house with fresh asphalt. I too got a 3.1 in 50 deg weather - the colder air has higher oxygen density so there is better combustion. After my 3.1 experience, I've been decreasing launch frequency - to increase the longevity of my ride, and decrease the likelihood of trouble:) I will get a few pops in, if feasible, when the weather drops another 10 degrees. #chasing2.9 Cheers.
 

·
Registered
Joined
·
412 Posts
Discussion Starter · #10 ·
Sweet! Please share your spot, I live in Addison and have been looking for a spot to put my TH in launch mode. Happy to hear 0 to 60 is around 3.0 seconds. I figured estimated 3.5 was beatable due to the horsepower to weight ratio of the TH..
Chapparrel Rd in E. Allen/ NE Plano. Way too far for you to drive from Addison. :)

I would think you could find a spot over there during off hours. Maybe even a service rd on the Tollway early in the AM or late at night.

But you're right... its a quick vehicle and low-3s are definitely there in good air with traction.
 
1 - 10 of 10 Posts
Top