Rovertrader
Supporting Sponsor
Anyone with actual experience please chime in- looking for real world data. Power upgrade- on/off road, fuel mileage better/worse, tire/gear combo, etc. Much thanks, and any long term experience -a big thank you!!
blower on a JK-pros/cons
- Thread starter Rovertrader
- Start date
JIMBO
Expedition Leader
:sombrero: Don't know what you're driving, but
Either RIPP/AVENGER SC addition, runs 4 to 6K and almost completely voids warranty-
There isn't much data on the extended life of the 3.8L/3.6L v6 after SC, so history is pretty scarce, however
No matter what year the JK--regearing can add 15 to 35% applied power and increase mileage-cost will be between $800 bucks and $2000 bucks/w no interface with the JK ECU-
You just have to decide what ratio and who to doit !!
It's a marvelous upgrade, for hiwy/off-road/towing/engine optimun ops !
:costumed-smiley-007:bike_rider: JIMBO
Either RIPP/AVENGER SC addition, runs 4 to 6K and almost completely voids warranty-
There isn't much data on the extended life of the 3.8L/3.6L v6 after SC, so history is pretty scarce, however
No matter what year the JK--regearing can add 15 to 35% applied power and increase mileage-cost will be between $800 bucks and $2000 bucks/w no interface with the JK ECU-
You just have to decide what ratio and who to doit !!
It's a marvelous upgrade, for hiwy/off-road/towing/engine optimun ops !
:costumed-smiley-007:bike_rider: JIMBO
ReconH3
Heavy Duty Adventurer
The people I know that have tried a SC on JKs have been very disappointed. Many blew their engines, and some removed them to avoid further damage. Not worth the money. I wish they had stuck to the old 4.0 that was do torquey out the box. 
"Ex Umbris Venimus"
Sent from my iPhone
"Ex Umbris Venimus"
Sent from my iPhone
Rovertrader
Supporting Sponsor
thanks, not what I wanted to hear, but was afraid I would...
I am very familiar with gearing and such, and hoping there was hp to be gained as this makes the gear selection less critical. For example my PW had 4.56s and I went from 33s to 37s and no regear as 400 hp and 400# torque compensated. Not so on the JKs -sadly. Considering the Hemi route but don't need the hp for the mileage trade-off. Looks like 4.88s or 5.13s
Any more input greatly appreciated...
I am very familiar with gearing and such, and hoping there was hp to be gained as this makes the gear selection less critical. For example my PW had 4.56s and I went from 33s to 37s and no regear as 400 hp and 400# torque compensated. Not so on the JKs -sadly. Considering the Hemi route but don't need the hp for the mileage trade-off. Looks like 4.88s or 5.13s
Any more input greatly appreciated...
JIMBO
Expedition Leader
:sombrero: Then My comments are just wasted-
I have an '08 JKUR/Auto and I installed 5.38 YUKON gears with my elockers-.
I can get up to 19mpg at 60mph and 17 mpg at 70 mph-
I can leave my auto in O/D and tow my trailer and no down shift
I have immediate throttle response and unbelievable action in 4hi/4lo-
You gotta run what ya brung-
Any JK/JKU is useless with any of the 4.10/4.56/4/88 gears--using an auto tranny-the 6spd manuals can feather whatever they want _
Good luck
:costumed-smiley-007:bike_rider: JIMBO
I have an '08 JKUR/Auto and I installed 5.38 YUKON gears with my elockers-.
I can get up to 19mpg at 60mph and 17 mpg at 70 mph-
I can leave my auto in O/D and tow my trailer and no down shift
I have immediate throttle response and unbelievable action in 4hi/4lo-
You gotta run what ya brung-
Any JK/JKU is useless with any of the 4.10/4.56/4/88 gears--using an auto tranny-the 6spd manuals can feather whatever they want _
Good luck
:costumed-smiley-007:bike_rider: JIMBO
Jimbo:
I think he is agreeing with you. He is saying he would love to do the Hemi- as would I, ... but not willing to sacrifice the mileage.
So, he is going to look at 4:88 or 5:16/
Are you saying that the gear ratio is too low and will not make up the lost speed due to low HP? and that the preferred is 5:38 only??
Please Clarify.
D
I think he is agreeing with you. He is saying he would love to do the Hemi- as would I, ... but not willing to sacrifice the mileage.
So, he is going to look at 4:88 or 5:16/
Are you saying that the gear ratio is too low and will not make up the lost speed due to low HP? and that the preferred is 5:38 only??
Please Clarify.
D
JIMBO
Expedition Leader
:sombrero: Heh Heh, the gear ratio for a JK/JKU Rubi, with D44 axles ( both), will support the 5.38 for an AUTOMATIC --
I've read and talked to different people for over a year before I put the 5.38s in and my jeep has a LOTTA mods and that alone was the most beneficial I ever did-
JK/JKUs with the D30 front/D44 rearaxle can regear with 5.13s and that seems to be the best all around gear ratio for the 6 spd manuals too--it doesn't race your engine it gives you a chance to use O?D on the freeway, using 33/34/35" tires
Now with the 2012 JK/JKU--ALL BETS ARE OFF--new animal and it doesn't need the gearing treatment that the 3.8L (07 thru11) does
The SC install is expensive and even questionable, because of engine longevity and warrantys and the HEMI swap is for social climbers and people that want the best in town, whether needed or not-
I have awakened my little 3.8L and there's no need for more power-
I can cruise at 70 mph/2600 rpm with 17mpg ALL DAY--in O/D
:costumed-smiley-007:wings: JIMBO
I've read and talked to different people for over a year before I put the 5.38s in and my jeep has a LOTTA mods and that alone was the most beneficial I ever did-
JK/JKUs with the D30 front/D44 rearaxle can regear with 5.13s and that seems to be the best all around gear ratio for the 6 spd manuals too--it doesn't race your engine it gives you a chance to use O?D on the freeway, using 33/34/35" tires
Now with the 2012 JK/JKU--ALL BETS ARE OFF--new animal and it doesn't need the gearing treatment that the 3.8L (07 thru11) does
The SC install is expensive and even questionable, because of engine longevity and warrantys and the HEMI swap is for social climbers and people that want the best in town, whether needed or not-
I have awakened my little 3.8L and there's no need for more power-
I can cruise at 70 mph/2600 rpm with 17mpg ALL DAY--in O/D
:costumed-smiley-007:wings: JIMBO
bldeagle10
Explorer
I agree on the hemi comment jimbo. more power yea but less mpg so it seems like it is just for show... another option would be turbo setup, but when off roading you don't want high rpm's and that is where you will make power. but on road you will get better mph and highway you will have some more pull. so, if you regear and turbo you would in my mind have an all around good rig...i wouldn't mind doing it to my 4.0 if I wasn't going stroker...
James Pierce
Adventurer
Dale,
Take the money and apply it to a new 2012. Wow what a difference. We ordered Brandy a new one and it shipped Thursday. Should have it by weeks end. Let the fun begin.
Dendy,
What in the world is that in your avatar? Doesn't look like a LR to me
Take the money and apply it to a new 2012. Wow what a difference. We ordered Brandy a new one and it shipped Thursday. Should have it by weeks end. Let the fun begin.
Dendy,
What in the world is that in your avatar? Doesn't look like a LR to me
Rovertrader
Supporting Sponsor
Thanks yet again, and Dendy is right, I was agreeing gears are the key. HP does provide a bigger window of options as you are saying with the '12s.
I had a '07 w/35s and sold it prior to gearing. The new owner did a Hemi and 4.88s and it was a monster- in a good way. However, at a huge cost fuel wise.
James- two LR to admire, aka artwork, and two JKs to enjoy??
I had a '07 w/35s and sold it prior to gearing. The new owner did a Hemi and 4.88s and it was a monster- in a good way. However, at a huge cost fuel wise.
James- two LR to admire, aka artwork, and two JKs to enjoy??
James - I sent you an e-mail to explain why I am roverless for the first time in 15 years ... and it feels great!!
The tech at NEMER Chrysler in NY that is re-gearing my truck says that the proper gearing will make up for the short-comings verses the HEMI. YES that dual exhaust twin ported tail-pipe earth shaking gut rumbling HEMI sounds awesome, and I have seen the videos of AEV greatly smoking a 2012 with a 2011 HEMI, ... but I am also trying to think about fuel economy as well.
Hate to blow a trips fuel budget in the first 300 miles!!
D
The tech at NEMER Chrysler in NY that is re-gearing my truck says that the proper gearing will make up for the short-comings verses the HEMI. YES that dual exhaust twin ported tail-pipe earth shaking gut rumbling HEMI sounds awesome, and I have seen the videos of AEV greatly smoking a 2012 with a 2011 HEMI, ... but I am also trying to think about fuel economy as well.
Hate to blow a trips fuel budget in the first 300 miles!!
D
Hilldweller
SE Expedition Society
I tried to talk Dendy and Dale into a 2012 but they found 2011s that they liked. I also tried to talk them into manuals rather than autos since I consider the autotrans the weakest of the 3.8L JKs' weak links.
To point out something that's not always obvious, Jimbo's results are not typical. Most JK owners who regear never get anywhere near the fuel economy that he gets. And even fewer tow a trailer as light as his.
I had an auto JK with 33s and 4.56 gears. I got about 16-17 mpg around town, 18 on the highway, and 14 pulling the Conqueror Compact.
But I couldn't get the poor thing up to 65 mph on the highway with the trailer; it would do about 63 mph before hunting for lower gears and screaming in a pitiful way.
4.88s might've been the answer but at what fuel cost? Logic used to say 4.88s for 35 but a 3.8L JK needs 5.13s to 5.38s for 35s. That's just to drive.
If you want to tow on the highway, good luck.
As for the blower, Dale, there's a guy in Colorado on Jeepforum that loves his. RIPP loves theirs. Everyone else I've met doesn't and that's why I traded the Jeep for the PW. I spent the same in trade as a Hemi swap would've cost.
To point out something that's not always obvious, Jimbo's results are not typical. Most JK owners who regear never get anywhere near the fuel economy that he gets. And even fewer tow a trailer as light as his.
I had an auto JK with 33s and 4.56 gears. I got about 16-17 mpg around town, 18 on the highway, and 14 pulling the Conqueror Compact.
But I couldn't get the poor thing up to 65 mph on the highway with the trailer; it would do about 63 mph before hunting for lower gears and screaming in a pitiful way.
4.88s might've been the answer but at what fuel cost? Logic used to say 4.88s for 35 but a 3.8L JK needs 5.13s to 5.38s for 35s. That's just to drive.
If you want to tow on the highway, good luck.
As for the blower, Dale, there's a guy in Colorado on Jeepforum that loves his. RIPP loves theirs. Everyone else I've met doesn't and that's why I traded the Jeep for the PW. I spent the same in trade as a Hemi swap would've cost.
JIMBO
Expedition Leader
:sombrero: For over a year, I've read about tremendous power/performance/mileage POSSIBLE increases with 5.13 and 5.38 gears--and the engine doesn't scream on the freeway--
You finally get to use O/D with very rare downshifts--this little v6 is red lined at 6000rpm(close) and 2000 to 3000 rpm cruising, is what it wants
At 60 mph--I'm turning 2250rpm-IN O/D
At 70 mph--I'm turning 2600rpm-IN O/D
Towing my trailer at 70mph--I'm turning 2600 rpm(16mpg) IN O/D
No these aren't just dashboard mileage indications, I initially checked using the gas/miles math-and the dash was usually 5% high-
Now HD says, thats not typical, right because most young, even older jeep drivers won't try that 5.13/5.38 ratio setup-BECAUSE THEY DON'T KNOW THE 3.8l V6
The 3.8L/auto JK/JKU 07 thru 11 is a great combo and the Rubi is ice on the cake--you MUST BE WILLING TO TAKE SOME CHANCES-
Now I spend most of my time off-road in 4hi, I couldn't before the aux cooler and regear-
Now I can still tow my trailer up hills, rocks in 4lo--2nd/3rd gear, with no excess tranny heat
I also have immediate throttle response in any gear 2wd or 4wd, because the ECU has retaught itself-that the HP/torque can be immediately delivered, without engine overload !
If you don't believe me, thats fine it's YOUR JEEP
I've been driving my '08 JKUR for almost 6 months since regearing and things keep getting better-the rear diff operates at NORMAL 165° F-QUIET
:costumed-smiley-007:wings: JIMBO
You finally get to use O/D with very rare downshifts--this little v6 is red lined at 6000rpm(close) and 2000 to 3000 rpm cruising, is what it wants
At 60 mph--I'm turning 2250rpm-IN O/D
At 70 mph--I'm turning 2600rpm-IN O/D
Towing my trailer at 70mph--I'm turning 2600 rpm(16mpg) IN O/D
No these aren't just dashboard mileage indications, I initially checked using the gas/miles math-and the dash was usually 5% high-
Now HD says, thats not typical, right because most young, even older jeep drivers won't try that 5.13/5.38 ratio setup-BECAUSE THEY DON'T KNOW THE 3.8l V6
The 3.8L/auto JK/JKU 07 thru 11 is a great combo and the Rubi is ice on the cake--you MUST BE WILLING TO TAKE SOME CHANCES-
Now I spend most of my time off-road in 4hi, I couldn't before the aux cooler and regear-
Now I can still tow my trailer up hills, rocks in 4lo--2nd/3rd gear, with no excess tranny heat
I also have immediate throttle response in any gear 2wd or 4wd, because the ECU has retaught itself-that the HP/torque can be immediately delivered, without engine overload !
If you don't believe me, thats fine it's YOUR JEEP
I've been driving my '08 JKUR for almost 6 months since regearing and things keep getting better-the rear diff operates at NORMAL 165° F-QUIET
:costumed-smiley-007:wings: JIMBO
Hilldweller
SE Expedition Society
Note that Jimbo added a real tranny cooler too. Very good advice to a pre-12 autobox JK owner that will tow.
And, like he says, gear it as low as you can.
And, like he says, gear it as low as you can.
JIMBO
Expedition Leader
:sombrero: A little trivia-
I think that with the new 2012, if you getta auto-you have to order MAX TOWING to getta aux cooler, so
They probably still run the stock cooler thru the A/C condenser and that means-
---Troubles a brewin !
I don'rt really know and I won't be getting one anywho !
:costumed-smiley-007:wings: JIMBO
I think that with the new 2012, if you getta auto-you have to order MAX TOWING to getta aux cooler, so
They probably still run the stock cooler thru the A/C condenser and that means-
---Troubles a brewin !
I don'rt really know and I won't be getting one anywho !
:costumed-smiley-007:wings: JIMBO