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Discussion Starter · #1 ·
I had a chance to go to the local track for a street legal drag racing night. Track was unprepped DA was 3700ft and my race weight was 5432lbs. 91 Octane 0 ethanol fuel.

I made a total of 16 passes using various methods of launching and drive modes some runs with a passenger and a run in 2H mode.

Without getting super technical and breaking down every single pass here are the takeaways.

  • This vehicle is FAST…..off the line it can keep up with some quicker vehicles for a little bit and then it falls behind
  • The PCM/TCM tuning on absolutely terrible. The vehicle basically completely gets out of the throttle during gear shifts although it doesn’t do that each time, it’s almost random in nature which makes it frustrating.
  • I could pull 1.9 60’ with All terrain tires
  • How you launch the vehicle directly affects how good/bad the vehicle performs.
  • ESP and TC Full off vs Partial off vs Full on had ZERO effect on times


My best pass of the night was






Here are the other “good” passes





I define a “good” pass as one where the vehicle shifted as it should, meaning that it shifted and kept the power going and I couldn't percieve a slow down. There is a serious issue with tuning where the vehicle pulls back the accelerator (gas) during shifts. Sometimes this happens sometimes it doesn’t. The best I could do to control this was change my launch slightly. The ideal times were 14.4-14.5 I could attribute the 14.5 “good” passes being heatsoaked which isn’t bad only losing 1 tenth due to hot lapping.

I ran in Hybrid mode for all runs except 1 where I did E-Save but there was no difference since WOT in E-Save is the same thing as WOT in Hybrid mode.

I would pull up to the staging lanes in hybrid with engine off. Once the pre stage lights were on I would go full throttle and foot on the brake so the ICE would start up and the let go of the brake once the tree dropped. This caused wheel spin and usually made the 1-2 shift really bad where the vehicle nearly stopped then started up again.

The best times I managed to get was in Hybrid mode pulling up with the ICE off then feathering the gas just far enough that that ICE would start. Once the tree dropped I let off the brake but waited about a second before I went full throttle, this still allowed me to get a 1.9 60ft but with no wheel spin and most times allowed the 1-2 shift to work without any issues.

I did a run in 2H mode which was the absolutely slowest of the night, but interestingly enough the MPH didn’t suffer that much







The following passes were in the 14.6 range and they all had the bad 1-2 shift and a slightly worse 60’ time. Most of these were the full throttle launch which caused wheel spin and caused that poor 1-2 shift.






The following were 14.7 runs

The 14.72 run had a good 1-2 2-3 shifts but it fell on its face for the 3-4 shift for some reason

The 14.79 run had a bad 1-2 shift, others were fine




The following runs were 14.9



The 2 passes with an opponent was with my friend riding along. These 2 passes were “good” without any perceived poor shifting.

The 3rd solo pass was without my friend riding along but with the bad 1-2 shifting, so I ran the same time as having an extra 200lbs with me because the shifting was bad most likely because I spun off the line as well. There is a video of this run, you can clearly see how the front end drops for a second before the vehicle starts accelerating again.






The following runs were in the 15 second range.



The 15.0 pass I did not brake torque and let it take off in electric mode and then have the ICE kick in, which was very slow, 2.4 60ft says it all.

The 15.2 pass I tried manually shifting and hit the rev limiter in each gear even though I made sure to “shift” up before getting to 5000rpm.



Here are the only other videos I got of the night





I did 16 passes last night. It was lots of fun, started with 90% battery and made my last pass with <1% battery, didn’t really make a difference as I still had the power available. I’m thinking had I started the night with no battery charge I probably would have got the turtle light at some point.



So tuning is major issue holding back more performance on the 4xe platform. I get its not supposed to be performance related but it’s still pretty bad. Here is a HP Tuners screen shot showing a “good” vs “bad pass where you can clearly see how the throttle is backed off on the 1-2 2-3 3-4 shifts on the “bad” pass but on the good pass the 1-2 shift is fine.





HP Tuners does not monitor PID's very well at all, just SAE ones and nothing vehicle specific which is what I'm used to, HP Tuners doesn't support the 4xe but also their GPEC5 PCM support on other vehicles (GPEC5 started in mid 2021 and all 2022s getting it) is a bit spotty right now. At the very least being able to monitor proper parameters might be able to better see what's going on.



There is probably more analysis I can do but I’ll leave this for now. I also have some interesting FORM stuff to post after being at the track as well.
 

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Just an FYI, this was full throttle brake torque and the 1-2 shift seemed fairly quick.


After watching this again

Lol at how much time it’s in second gear, and how long 3rd gear is comparatively.


Man, I bet some smaller tires (or shorter diff ratios) that make 3rd gear top out at 61mph, and then starting in 2nd, would make this thing fly to 60
 

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Very nice runs - I think I am more impressed that you got in 16 passes - here in NJ at ATCO if I get 4-5 passes in during a test-n-tune session that's a lot. Would throw the Dragy on my Rubicon and see what I can do, but I have so much added weight on it now it would be meaningless.
 

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So looking at some Draggy videos in the Rubicon.
They are generally
Just under 2 sec 60'.
5.27 sec 0-60.
8.76 @ 79.64 mph 1/8.
11.42 @ 91.95 mph 1000'.
I let of just after 1000'
13.83 @ 88.65 mph .

My fastest 1/8 was edit mph. 79.80mph.
 

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There is a good 1/2 second in the trans.

Hilarious that when I started going to the drag strip that was a OK run for a LT1 V8 Camaro.

I thought the 1/8 mile would have been better and figured for sure you'd hit the speed limiter.
 

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There is a good 1/2 second in the trans.

Hilarious that when I started going to the drag strip that was a OK run for a LT1 V8 Camaro.
Just a heads up, as of 2016, you gotta specify which lt1 v8 camaro.

one of them is about as quick as a chevy tahoe on a circuit track, the other is making porsche track rats switch to chevy

(I know which one you’re talking about lol)
 

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Discussion Starter · #14 ·
Not saying draggy isn't accurate but 92mph in the 1/8 would indicate you are faster than a 392 wrangler, which probably isn't the case. As always there are lots of variables, but actual track times don't lie.
 

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Discussion Starter · #15 ·
There is a good 1/2 second in the trans.

Hilarious that when I started going to the drag strip that was a OK run for a LT1 V8 Camaro.

I thought the 1/8 mile would have been better and figured for sure you'd hit the speed limiter.
There isn't enough HP to get close to the speed limiter in the 1/8 or 1/4 mile. If we compare these times to my 2014 5.7 grand cherokee stock times from a MPH Perspective the 4xe is making similar HP....but much more torque. I'll dig out my slips and compare them.
 

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Discussion Starter · #16 ·
Here is a compairson of my best time with my 2014 Grand Cherokee 5.7 completely stock down to the air filter, same track.
DA was 2560ft and race weight was 5520lbs



[email protected] What's interesting is that the MPH is very close, mph is a good indication of horsepower, the WK2 5.7 is rated at 360hp/390tq

Everything really makes sense from a power perspective, nearly the same HP but less torque and the times reflect that.

If we look at the corrected times to take DA out of the equation which isn't totally an accurate calculation but helps



The 4xe is faster all around but it starts to fall on its face as the speed rises, which makes sense due to being a brick on wheels but the 470ft/lbs really makes it a good 1/8th mile racer.

If we took the poor shifting out of the equation i'm thinking the best run I could have done last night would have been around [email protected]

I might be able to get both my 4xe's at the track together if my wife is up for that (very unlikely) if not then i'll just take the Sahara to the next street legal night.

My guesses if the 2021 performed the same way would probably run a [email protected] if it doesn't have shifting issues it would probably be close to a 14.0
 

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There isn't enough HP to get close to the speed limiter in the 1/8 or 1/4 mile. If we compare these times to my 2014 5.7 grand cherokee stock times from a MPH Perspective the 4xe is making similar HP....but much more torque. I'll dig out my slips and compare them.
I keep thinking of a JB4....I've run them on all my Audi's...they say it should work with a 4XE.

As a previous poster says the 80-98 mph is very strong which is why I felt it would hit the limiter but as he also says it does seem different from a dead stop versus at speed which makes me wonder if the IC is too small.
 

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Discussion Starter · #19 ·
JB4 isn't going to do anything if the vehicle's torque management is pulling timing and/or the accelerator during shifting. There is a YT video where a guy spent 2 grand on mods for a 2.0 JL wrangler and got virtually no gains, and as I keep on saying unless you properly tune the PCM and TCM piggyback modules thar intercept the map sensors ect really don't do much and aren't worth their cost. It's either wait for HP tuners to support it and then void warranty by tuning or just deal with how the vehicle performs which is just fine because it's not designed for drag racing either.
 

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JB4 isn't going to do anything if the vehicle's torque management is pulling timing and/or the accelerator during shifting. There is a YT video where a guy spent 2 grand on mods for a 2.0 JL wrangler and got virtually no gains, and as I keep on saying unless you properly tune the PCM and TCM piggyback modules thar intercept the map sensors ect really don't do much and aren't worth their cost. It's either wait for HP tuners to support it and then void warranty by tuning or just deal with how the vehicle performs which is just fine because it's not designed for drag racing either.
Why they may not be worth it due to torque management on the Wrangler they do wonders for every other platform.

E40 and a JB4 on my 3.0 Audi Turbo makes huge gains.

Chrysler/Stellantis has always had the worst or more aggressive torque management regardless of the trans.
 
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