Novak Conversions Jeep Wrangler TJ radiator

100 mph in a TJ; have you done it?

It goes away at 53 mph. Ignore the personalized plates. CNN took that pic. 🇺🇸

View attachment 619339

Curious about

1. Impact speed estimate?

2. Impact object?

3. Driver/Passenger injuries?

I'm surprised that my 97 TJ has much better front impact crash scores than my 97 XJ.

I have much more modern cars with far, far better crash protection. But they're SO BORING so I hardly ever drive them except to keep the gas fresh.

Nevertheless, I really hope I never crash the TJ, and especially never the XJ.

Wish I never saw the XJ TJ crash test videos
 
I have you beat :) 114 mph verified on the GPS. Governor kicked in and scared the crap out of me. I thought something broke. 06 TJ, softtop with the NSG370. Stock everything including the tire size. I just HAD to know where the limiter was set but wasn't expecting it to kick out so abruptly like that.

My Jeep seems to like 85 mph as well. My RPMs are 2500 at that speed so it's nice and calm. 100+ doesn't feel bad. I can cruise at that speed comfortably but my suspension is in great shape and of course I don't have a lift either. At about 95 I've noticed the front end feels a little floaty, I think that's where the other poster that said it feels "smooth" is coming from. Honestly the reason I don't cruise at 100+ on wide open interstates is because gas mileage is in the single digits and the 4.0 doesn't feel like it has much reserve power. :D

Also, any emergency maneuvers at that speed would not go well in a little short wheelbase box.
 
Never 100, at least not in my TJ. Fastest I've had mine up to was just shy of 90, and that was down a hill on the interstate. She had more, definitely, but at that speed it's a bit twitchy, and I enjoy not testing to make sure the roll cage works.
 
My brother bought a SRT-10 truck and got it up to 142 mph on the drive home. I just wondered why? Not a way I want to die. :unsure:
View attachment 618767

I have one. 93+ Tuned with intake, exhaust, some suspension work, etc. 145 is easy and quick to get to and it's really well grounded but that's about where it starts to feel scary. I've never gone past maybe 150ish but it keeps pulling pretty well at that point.

As for the TJ, the '05 has a factory limiter at 92 mph, at least with the 6 speed. I hit it once on 4" and 35s the only time I tried, fairly easily back when I was younger and dumber. I've since raised the limiter to 150+ with the 5.13s and an Eaton blower. Wind resistance increases at the square of speed so my guess is somewhere around 100-105 is where it would probably run out of juice even with the blower but I'm certainly not interested in testing it.
 
Last edited:
  • Like
Reactions: TheBoogieman
I only know of one way to get my TJ up to 100 MPH

towing home.jpg
 
I have one. 93+ Tuned with intake, exhaust, some suspension work, etc. 145 is easy and quick to get to and it's really well grounded but that's about where it starts to feel scary. I've never gone past but it keeps pulling pretty well at that point.

As for the TJ, the '05 has a factory limiter at 92 mph, at least with the 6 speed. I hit it once on 4" and 35s the only time I tried, fairly easily back when I was younger and dumber. I've since raised the limiter to 150+ with the 5.13s and an Eaton blower. Wind resistance increases at the square of speed so my guess is somewhere around 100-105 is where it would probably run out of juice even with the blower but I'm certainly not interested in testing it.

I think it's the Rubicon models that have a limiter at 92. My 06 X trim definitely does not.
 
I think it's the Rubicon models that have a limiter at 92. My 06 X trim definitely does not.

Very well could be. I only noted 6 speed because it was the only notable difference that popped into my head. Usually these factory limiters are based on tire speed ratings. Totally makes sense the Rubicon would be limited lower.
 
Idiot's guide to launching a TJ:

Start in 4Hi and 1st gear. Lock the rear diff if you don't have an LSD.
  1. Rev engine quickly to 3000-3500 RPM
  2. Half-drop the clutch
  3. Floor the gas pedal and simultaneously modulate the clutch to bog the engine down to about 2000 RPM
  4. Shift at ~5400ish RPM (note the tach has a bit of delay) (or 5200 if your rev limiter isn't raised)
  5. While up-shifting, just drop the clutch at the exact instant the gas pedal is floored (takes practice to time it, if the revs are matched it's super smooth)
Once you get really good, you can floor the gas pedal with the clutch in and just let it out at the right instant to bog it down from 3000 to about 2000 all in one fell swoop.

Same with power-downshifting. Say you need to go from 6th at 1800 RPM to 3rd at 3600 RPM to pass some elderly person. If you can floor gas the pedal so that the revs match at the instant you drop the clutch, it is a very smooth and fast take-off, just like a modern auto skipping gears in a downshift.
 
Last edited:
  • Like
Reactions: Swiss-cheese TJ-6
Idiot's guide to launching a TJ:

Start in 4Hi and 1st gear. Lock the rear diff if you don't have an LSD.
  1. Rev engine quickly to 3000-3500 RPM
  2. Half-drop the clutch
  3. Floor the gas pedal and simultaneously modulate the clutch to bog the engine down to about 2000 RPM
  4. Shift at ~5400ish RPM (note the tach has a bit of delay) (or 5200 if your rev limiter isn't raised)
  5. While up-shifting, just drop the clutch at the exact instant the gas pedal is floored (takes practice to time it, if the revs are matched it's super smooth)
Once you get really good, you can floor the gas pedal with the clutch in and just let it out at the right instant to bog it down from 3000 to about 2000 all in one fell swoop.

Same with power-downshifting. Say you need to go from 6th at 1800 RPM to 3rd at 3600 RPM to pass some elderly person. If you can floor gas the pedal so that the revs match at the instant you drop the clutch, it is a very smooth and fast take-off, just like a modern auto skipping gears in a downshift.

Ouch. I'm hoping my TJ lasts another three decades, at least. I'm so gentle with it.
 
  • Like
Reactions: Zorba
I know this is an old thread, but I remembered I had this pic of my dash when I was going 105+ in my stretched TJ on 40s. I’ve GPS-tested it and my speedo is dead-nuts accurate. Does push high on the revs though. Fastest I’ve gone is somewhere north of 115. I backed out because I was hitting redline—my poor 4.0.


IMG_9529.jpeg


IMG_8848.jpg
 
I know this is an old thread, but I remembered I had this pic of my dash when I was going 105+ in my stretched TJ on 40s. I’ve GPS-tested it and my speedo is dead-nuts accurate. Does push high on the revs though. Fastest I’ve gone is somewhere north of 115. I backed out because I was hitting redline—my poor 4.0.


View attachment 655292

View attachment 655293

Are your tires rated to that speed? lol

If you have the Milestar Patagonia X/T 40X13.50R17 D/8PLY, the speed rating appears to be Q (99 mph).

Madlad
 
Last edited:
Are your tires rated to that speed? lol

If you have the Milestar Patagonia X/T 40X13.50R17 D/8PLY, the speed rating appears to be Q (99 mph).

Madlad

You’re absolutely right, I never really thought about the speed rating on the tire. I’m sure there’s a safety factor built into the rating though- probably at least 1.3 percent—so I bet I could’ve gone 130 before it became a problem. ;)
 
Novak Conversions Jeep Wrangler TJ radiator