Engine/Transmission (1998.5 - 2002) 4.10's or injectors?

[smpdodge99]

I just recently bought new tires for my truck 315/75/16's . Love the look but they sure do slow it down. I do alot of driving in and around town. My question is for those of you that have been in this situation. Should i opt for the gears or just my some new injectors. I'm not sure if i want if want to lay down roughly a grand/yr for tires if i stick in new gears. If I install new injectors will I get the power and mileage back.

 

[Huff N Puff]

With a much heavier set of tires you will not get the milage back with either the injectors or the 4. 10s in around town driving.

 

[lsenus]

My '99 now has 285/75/16 on it. Mileage dropped 3-4 mpg. It's the rolling resistance of the larger surface arear that is killing the milleage. My 4. 10's limit my top speed to around 80-85 mph. Get the linjectors, get the power. Larger tires make for smokier burnouts!

 

[C.Solomon]

I run 285's on my 99 also and I didn't see a drop in mileage. Are you sure you are taking in acount that your speedo is reading slower and that inturn will turn less miles.



After I went from 235's to 285's the speedo is off 9. 5-9. 8%, and if you figure that in, you true mileage is 2-4 mpg better then reading straight off of the odometer.

 

[TGibbs]

Be weary of the transmission when going with big tires and not reducing the gears. If you put the injectors in and no gears, stomping on it off the line, your torque converter will be screaming :{

 

[Hohn]

I'd do injectors, but you won't get the mileage back-- just the power. You MAY get some mileage back on the hwy, depending on tire pressure and tread, but don't count on it. In town, 315s will ALWAYS give worse mileage unless you were running like a 265 size Swamper or something before.

As easy as it is to add power to these trucks, I'd much rather add power to tall gears than add gears to the same power.

Do respect the power's potential to damage the auto trannies. Hence, my purchase of a 6-speed.

 

[BDR]

I'm in the same situation, I just got some new 325 Toyos. I personally am going to swap in some 3. 73s due to the drag with the new tires. I don't tow so 4. 10s would be a little much for my driving. But I want to get the gears before I go playing with the engine. IMHO I would go gears before injectors.

 

[johncameron]

We can only get 3. 54 and 4. 10 gears for our years. 3. 73 is for the 2003+ HPCR models



J

I'm in the same situation, I just got some new 325 Toyos. I personally am going to swap in some 3. 73s due to the drag with the new tires. I don't tow so 4. 10s would be a little much for my driving. But I want to get the gears before I go playing with the engine. IMHO I would go gears before injectors.

 

[Regcabguy]

3.73 gears

We can only get 3. 54 and 4. 10 gears for our years. 3. 73 is for the 2003+ HPCR models



J

I'm driving a 99 w/Dana 70 and just had mine regeared to 3. 73. It "normalized" my gearing to the stock setup w/245-75-16. I'm running 285's. The installer recommended 4. 10's if I wanted to run 315's. I remember the hits I took in power and economy first:285's. secondly:1800lb camper. Brakes weren't too thrilled either. :{ If it weren't for Baja trips requiring flotation,I'd probably go back to the micro tires. They look awful but are very functional for the street. 3. 73's are available for the Dana 70,although I don't know about the 80.

 

[SKneeland]

3. 54s here and no problems doing burn-outs, nor getting close to 25mpg... .

 

[Beast2B]

do you tow much? heavy? i went with the power increase over gears. with the 6speed i can tow in 5th gear 60mph 2000rpm. running empty is EXCELLENT with 3. 54 and larger tires. i lost ~2mpg with the lift kit and wheels/tires. I did not gain the mpg back, but there is MORE than enough power to make up for it. first geat starts at stop signs is normal now for me. assuming your trans can handle it, throw a set of Don's EDM Mach2 injectors in and enjoy the ride!

 

[klaybus]

285's to 295's

I just retired the 285s & went to 295 BFGs & lost 2. 5 mpg... . :{ I'm going to re-gear to 4. 10s. I figure a gear swap is less $$ than a new DTT Trans. It will also help while pulling the 5vr. At 62 mph with the 3. 5s, the auto trans & 295s I'm only turning about 1500 rpms in OD & thats no good. When I tow in 3rd direct (no OD) I'm running at about 2200 rpms to go 60 mph. I hope to achieve somewhere right around 2000 rpms with 4. 10s in OD..... I figure mileage might even improve back to the 17-18 mpg hwy with the 4. 10s. . We'll see.....



Clay

 

[JJ Jackson]

do you tow much? heavy? i went with the power increase over gears. with the 6speed i can tow in 5th gear 60mph 2000rpm. running empty is EXCELLENT with 3. 54 and larger tires. i lost ~2mpg with the lift kit and wheels/tires. I did not gain the mpg back, but there is MORE than enough power to make up for it. first geat starts at stop signs is normal now for me. assuming your trans can handle it, throw a set of Don's EDM Mach2 injectors in and enjoy the ride!

Agreed If you tow heavy you'll prolly want the 4:10s also. But for a daily driver you'd be fine with some Mach 2's and stock gearing.



Let's face it, you never get the mileage back with big tires so you might as well get more power. ... ... Jim

 

[smpdodge99]

thanks to all that gave there input, I do tow a trailer (3500-4000lbs) from mid march to end of november daily. take of is really where the truck seems to suffer. Thought gears might help but that would limit my tire choices in the future. Maybe I'll do the sticks and see how she responsed