Scott Brady
Founder
I have tested the 2.8CRD in the JK and loved it. Surprising power and 25mpg economy.
Why the JK 3.8L V6 sucks.....the video!!
- Thread starter Cole
- Start date
Finatic Angler
Adventurer
I dropped a 400 HP small block in a S10 years back. It was a tough project but well worth it.
The big diffrence between now and then is the electronic parts. The S10 was carbed so the swap was very straight forward.
Next step is to get the JK
The big diffrence between now and then is the electronic parts. The S10 was carbed so the swap was very straight forward.
Next step is to get the JK
Backwoods Rambler
Explorer
Mike, do yo have stock gears or did you still have to gear up for the bigger tires even though you have real power?
Backwoods Rambler
Explorer
I would be if I had either a JK or a Hemi, but I have neither. Thanks anyway :costumed-smiley-007
EDIT: Duh, I see it in your signature now....
EDIT: Duh, I see it in your signature now....
Last edited:
The Swiss
Expedition Leader
Hmmm, I just returned from a 2,100 mile trip from GA through MI and back, over various hills, through all kind of conditions, pulling a small, very light trailer 2/3 of the way, cruising between 70 to 80 mph, averaging a respectable 19.8 mpg. Somehow I'm missing the "sucky" part of this engine.
I had a WJ with the 4.0 I6 for 5 years/125,000 miles. I take the 3.8 V6 over the old 4.0 I6 anytime.
I had a WJ with the 4.0 I6 for 5 years/125,000 miles. I take the 3.8 V6 over the old 4.0 I6 anytime.
Cole
Expedition Leader
Backwoods Rambler
Explorer
You missed the 9,000 to 11,000 foot climb at 6% grade
Don't forget..."for a few miles"....least folks think this climb is just a quick jaunt :ylsmoke:
MossMan
Adventurer
Now don't take this the wrong way but, I find this hard to believe. :Wow1: Can you tell me more about your setup? Tires, gears, etc.?
Root Moose
Expedition Leader
I don't doubt it. A light foot and flat land travel. The part he didn't have was:
You missed the 9,000 to 11,000 foot climb at 6% grade
At 9000ft the engine is making ~30% less power than at sea level.
Forced induction or a larger engine or just putting up with it are the only things that can be done to solve the issue IMO.
FWIW I still don't understand why Jeep didn't have the 4.7 as an option in the JK. It's as plain as the nose on your face that the engine isn't big enough for that size vehicle. Even the old 4.0 wouldn't have been enough engine I'm guessing.
I heard rumours that the 5.7 was considered and dropped because the vehicle wouldn't pass crash testing with it. Don't know if that is fact or fiction.
4.0 just won't pass emissions. End of story. Stop asking for it.
I wish Ford would buy Jeep. The turbo 3.5 V6 and the new 5.0 V8 would be awesome engines for the JK.
Last edited by a moderator:
Hilldweller
SE Expedition Society
He has an Unlimited Rubicon, 2.5" BB, stock 4.10's and tires.
And Michael doesn't drive like most people drive; he uses techniques that I've seen described as "hyper-miling". He actually thinks a little...
It should be added that, in stock trim, the JK's odometer reads quite optimistic and often teases its owners with a somewhat false sense of speed and fuel economy.
When we did our first big (7000+ miles) roadtrip, we logged and calculated all mileage off of our gps as well as our odometer. Even though I was running non-stock 265/70-18 tires at the time (took up some of the slack from the stockers), the discrepancy was still large.
All that considered, our gps-corrected average mpg for the entire trip was 20.98 mpg; there were 3 tankfuls where we got just under 27 mpg --- high altitude and speeds under 55. This was in our very stock 2-door Sahara, autobox, 3.73 gears, General Grabber AT2 tires.
Last edited:
The Swiss
Expedition Leader
Well, my board computer was somewhat optimistic; calculating actual driven miles and gallons filled over this trip, I come to an average of 19.4 mpg. The trailer was an empty, low profile carry-on mesh trailer, so on the interstate not a big factor. And yes, I do drive very light footed (growing up in Switzerland where gas prices have been in the $5 range for the last 25 years, driving light footed becomes a second nature) and I am not afraid to let speed drop to 60 mph in inclines.
Over-all average of my JK (lot's of small town and interstate driving, not much congested big city traffic) is in the low to mid 18mpg. Set up is automatic, 2.5 inch lift, stock Rubi wheels and gearing, K&N drop in, Stage 1 chip, regular 87 fuel.
That's exactly my point. Is a JK supposed to fly up a 9,000 to 11,000 foot climb at 6% grade? Is it that bad - even in our fast paced time - to content yourself with a slower speed for extreme conditions like this? A JK is not a speed demon, but an Off-Roader that does any kind of daily duty darn well. Most of the time we complain about SUVs getting too soft. Now here we have one of the last true off-road vehicles and we are complaining about it loosing speed at 6% grade at high altitude?You missed the 9,000 to 11,000 foot climb at 6% grade
I don't get it, but that's maybe because I'm becoming an old fart remembering times where it was an accomplishment to cross the Alps without having to take breaks to let the engine cool down, simply making it.
Old fart gets off the soap box. :elkgrin:
Last edited:
The Swiss
Expedition Leader
True. Speedometer at 75, my GPS records a speed of 73, which would mean the speedo is about 3% off. I believe the GPS to be pretty accurate.
Pskhaat
2005 Expedition Trophy Champion
Why is this?
Root Moose
Expedition Leader
I should clarify, that's speclation on my part. I don't have any inside line to what goes on at ChryCo...
There's nothing left to tweak.
Between the three catalytic converters, EFI, DIS, TCU/ECU conversation there is nothing left to do with the old cam in block tractor engine to get it to pass further stricter emissions. Kinda bummed they didn't investigate variable cam timing and/or low friction valve train... or just maybe they did and it wasn't worth the effort to productise.
What's left to do to the 242? Anything else and you are at designing a new engine scale of effort.
There's nothing left to tweak.
Between the three catalytic converters, EFI, DIS, TCU/ECU conversation there is nothing left to do with the old cam in block tractor engine to get it to pass further stricter emissions. Kinda bummed they didn't investigate variable cam timing and/or low friction valve train... or just maybe they did and it wasn't worth the effort to productise.
What's left to do to the 242? Anything else and you are at designing a new engine scale of effort.