Quote:
Originally Posted by Gojeep
Just a update on mileage after installing the following mods. Unfortunately I couldn't do any testing between them as I don't drive it that often. First I fitted a throttle pedal controller which should have no effect on mileage as doesn't affect engine tune at all. Best bang for your buck and ease of installation for sure. Felt so much quicker off the mark removing all lag. Next I installed dual 2.25" exhaust from the cats into a two into one muffler with 3" tailpipe. Felt most improvement from mid range to high revs and sounds so much better. Next I fitted the Hypertech MaxEnergy 2.0 on the regular gas tune. Reason I don't run higher octane fuel is that the octane boosters diminish over time and it is often a couple of months for me between refuels. I felt no improvement at all fitting this to be perfectly honest. Others on the higher fuel tune say they do. Lastly I fitted the bigger 3" 4.7 V8 throttle body. Got obvious gain especially in the higher rev range where it pulls hard right to the gear change. Overtaking is much quicker and safer.
Now before all these mods I drove down to the beach and back which is a 50/50 mix timewise of suburban and highway and 250 km/155 miles return. Drove it again the same route after the above mods again starting with a full tank and a reset of the trip computer. Speedo reads dead on to the GPS with 245/70R17 tyres with the dealer setting the computer to 245/50R20 tyre size, which is the tallest they can do. I also have a 2" lift but no added weight from aftermarket bumpers or wind resistance from a tyre on the roof etc. These mods were done before the first test so results are directly comparable as even had the same one passenger and dog on board. Tyre pressures were the same for both tests set at 2.0 bar or 29 psi. Bigger the tyre the less pressure needed for the same load. Before mods I got 12.7l/100km, or 18.5 mpg US. With all this extra power but still driven the same for the test, 11.7l/100km or 20 mpg US. I feel no power loss now at all from running the taller tyres and feel slightly ahead if anything. I would have been happy paying a small mileage penalty for the power gain but got a gain instead.
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Thanks for the update. Really good info! I actually follow your thread on LostJeeps as well but thought to comment here.
I have done everything that you have done to your KK except for the exhaust. I will need to do something soon as my exhust has a giant kink in the middle (long story that I don't actually have an explanation of how it got there...).
I am currently still running 29" tyres albiet more offroad focussed and 255 wide.
I have the hypertech programmer, set to the premium fuel tune. It def is noticebly better. Throttle is more responsive. Not by a massive amount, but not as do'ey and pulls harder towards redline. Although after reading your feedback, I can't wait to get my exhaust fixed!
First thing I did was fit the RAM 4.7v8 throttle body years ago.
I also have a elec throttle controller on mine now too. I took it off my JK before I sold it as it convieniently has the same plug and worked perfectly. I don't like an overlery sensistive throttle, or an artificially "man this thing feels fast!" kind of setting, as like you said it doesn't change the tune of an engine, so I have it on a very mild setting. Just enough to get rid of the inital lag and to make the pedal feel more like a cable operated throttle (not as per whatever throttle map that the manufacturer thinks is best for its customers).
However, after having it installed for about 2 months now, my KK started throwing a P2138 code and restricting the throttle. The code relates to incorrect throttle position and pedal correlation... I kept clearing my code and it would drive fine for about 10 mins and then come up again. I have now disconnected the throttle controller and so far I have had no issues for about 1 week now. Strange that you haven't had this issue, especially as I think you also have the Cammus elec throttle controller like me with all the same mods as well (throttle body and Hypertech tuner).
Anyway I have a downstream catalytic converter that's apparently on its way out... Side note: KK's will throw a code for a bad downstream catalytic converter if it is below 90% efficiency, so technically the cat is not bad yet, it just doens't allow the KK to meet its emission regs. Anyway, so I am going to address that and then put plug in the elec throttle body and begin trialling it again.
Just FYI, you can use the 'OBD JScan' app along with a decent (not cheapo) OBD2 ELM327 adapter and configure a bunch of factory settings on the KK (and many other modern Jeep models). It is the first app/program that will allow the user to correct their speedo for changes in tyre size and diff ratios. I know you prob won't be changing that stuff, but it is a handy app to have nonetheless and what some KK owners have been asking for.
Love you builds and updates as always.
Oh and thought I'd mention that I followed your post about the rear door hinge mod and driver seat lumber delete. Have done them both! I am much more comfortable in the drivers seat now and back passengers can get in and out more easily.