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-   -   Both My Hemi's At The Drags (http://www.jeepgarage.org/f5/both-my-hemis-at-the-drags-22844.html)

jeepgcoman 05-06-2011 03:17 PM

Both My Hemi's At The Drags
 
A couple weeks ago I took both my Hemi vehicles (LX and WK) to the drags for their first side by side encounters. I knew the LX was alot faster, and this sure proved it. Both vehicles are modded exactly the same, but there are still obvious differences between the two. Here are the weather conditions, type of tunes, ET's and speeds (actual and corrected to sea level), followed by other known/perceived differences.

Track elevation: 3000 ft.
Density altitude: ~2800-3200 ft.

Both vehicles were tuned with modified (timing and A/F ratio) Diablosport 93 tunes.
Fuel in both were straight gasoline and were not ethanol blends.

Jeep......................Magnum
4765 lb. w/o driver....4115 lb. w/o driver
So, 650 lb. difference in weight w/o drivers

3/4 tank gas (87)......1/4 tank gas (91)
So, ~60 more lbs. of fuel in Jeep

15.88 lb/hp (est.)......13.71 lb/hp (est.) Both estimates are 300 rwhp

Run 1
15.342@90.17...........14.266@99.67
14.787@93.60...........13.752@103.46 Corrected to sea level

Run 2
15.163@89.91...........14.126@99.30
14.614@93.33...........13.611@103.08 Corrected to sea level

Run 3
15.146@89.26...........14.090@99.37
14.60@92.66.............13.582@103.15 Corrected to sea level

Other differences
--Jeep has lower overall gearing in first and second gear only.
--Jeep has some parasitic drivetrain power loss due to transfer case and front drive, but also has better traction.
--Jeep has more frontal area which affects aerodynamics.

Bottom line, IMO, is our Jeeps are big, heavy slugs, but actually move pretty well for what they are.

4.whoa 05-06-2011 04:05 PM

Re: Both My Hemi's At The Drags
 
I could be remembering this wrong,but isn't every 100lbs about a tenth/sec?
If so, the 710 lbs could make it .7 sec quicker and it's only about a sec behind the lx.......pretty good.
I take it those were canned tunes? maybe a toona tune could negate the weight handicap?

Regardless, great job :thumbsup:

jeepgcoman 05-06-2011 07:16 PM

Re: Both My Hemi's At The Drags
 
I think you're right about the 100 lbs. per tenth. Yes, the tunes are canned tunes. I made slight adjustments to the timing and fuel mixture, but with only 3 runs it's kind of tough to zero anything in for certain. When I do the cam (either a new one or advance the stock one) I'll probably get a CMR tune for it. If all works good then I'll do the same thing to the LX.


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