Tires are hurting PSD towing performance

[Meat_]

Yup, I don't get 22mpg towing like everyone else with a turbodiesel.

With 285's/295's on my 2002 excursion 7.3, I get 11mpg around town (stop and go on surface streets) or towing my jeep to Moab. That includes timing lights, coasting, driving mellow, etc. At the same time and under the same conditions, I can go get on I-15 and do 65 and get 18ish.

btw, when I'm towing, I'm going wtih the flow of traffic, maintaining 70 over Soldiers.

Good points on the tranny...that's something that has been hanging in the back of my mind.

Yeah wouldn't 22mpg be nice..... but 11 is still pretty low, I'm wondering if your injectors are partially plugged.
Oh, and 2,000 RPMs is the magic number on all the diesels (powerjoke, cummins, dmax) for mileage.

Carl.

Yep, or down to Kevin at 6States in Orem....

yup, or John at Gaylon's in Lehi.

 

[gijohn40]

I can't speak about diesels due to I have gasser... but my expedition got like 11 when I went to 35x12.50x17 from my 265s... I was getting 17... it also was doing the shifting up and down like yours.... so I changed my gears to 4.56 and got my mileage back up to 17 mpg and the shifting stopped as well...

Seeing my expedition is a 98 they say that power programmers don;t work on mine and I can't change the cumputer so I can't get the speedo to run accurately... so have a gps fixed in the beast!

 

[MR.CJ-7]

Here is my experience with PSD and 315's.

I had an early 99 with a manual trans and went from the stock 265 to 315's. I saw a HUGE hit to my powerband and mileage. Empty my mileage went from 17ish to 14ish. Then I hooked my aprox 10K bumper pull TT to it. Oh my God! I couldn't even pull in O/D anymore except maybe on the downhill runs.

I ordered up a DP chip after hearing all the rave on thedieselstop.com I did the F5 switch with stock, 40T, 80T and econo. I ended up using the 80T as my daily driver setting and liked the power recovery. It more than made up for the tires. It rolled some mean smoke. The manual trans was nice for smoking ricers, just dump it in O/D at 30mph and pound the skinny pedal I could fog out the whole area It was slippery as hell on snow and ice (too much torque), I went back to stock or sometimes 40T in the snow.

For towing I found I made WAY too much heat. I could easily hit 1400 sometimes 1500 on the pre-turbo pyro no matter what gear or RPM I ran. Most of the time on the hills I ended up just pulling with my stock program to try to keep heat in check. People from the board told me I had an intake leak (boost leak) I checked it found some small leaks, but saw no difference. I took it to two performance shops, one found the up-pipes slightly leaking, but no other leaks. I fixed those still no better. I finally put in a bigger intercooler (from a 6.0) that helped a little but still no better. I thought it must be the exhaust. I pulled the whole thing off except the downpipe, still no better.

The 80T setting would slip my OEM clutch if I made a hard shift fromO/D to 4th like when pulling a hill. I've heard pretty much all DP's tunes are hard on auto's, so start saving for an upgrade.

After all that then I noticed my turbo surging, where it never did that before. Since I had the early 99 I already had the "wicked wheel" everyone used to fix surge. So I was up a creek. I was set to do the 99 to 99.5 conversion and put a big a$$ turbo on it, but we found out a baby was on the way and wifey said no way an extend cab was going to work, so longer story short I now have a crew cab Dmax.

Everyone on the board said mine was just way too hot for some reason and they all claimed to tow the world on 80T. I know I couldn't. Maybe my truck was F'ed up

I don't know about re-gearing, in theory it should help, but no matter what trans gear (RPM) I ran I couldn't keep my heat in check. I read a few other posts that said the same thing after gearing to 4.30's and 4.56's.

I was ready to drop down to 285's, but the truck got traded first. I didn't really want 315's but I bought the rims from KSL and the guy made me such a good deal I figured the tires were pretty much free.

I think 285's are a good all around size. That's what I'll be putting on my Dmax when the stockers are done.

Good luck!

 

[waynehartwig]

... That's why I like the Edge programmers. It seems like I hear those types of horror stories with the DP and Hypertech on a daily basis. I've yet to hear those complaints out of Edge customers. I sell them all, so I'm not bashing one to sell another.... It seems like the Edge controllers have check features installed. So that when it's increasing the HP/TQ, it's also checking sensors for too much heat, slippage, etc. and will defuel when they get to unsafe levels. The other programmers don't do this.

 

[1993yj]

I have the Hypertech programmer for my Hemi, and it made a difference in power, but mileage sucks (it does stock with these engines though). I have been toying with the idea of going from 4.10 to 4.56 gears for these same reasons. Seems like gijohn40 had some good results from regearing, enough maybe to help justify the cost of new gears.

 

[Kiel]

... That's why I like the Edge programmers. It seems like I hear those types of horror stories with the DP and Hypertech on a daily basis. I've yet to hear those complaints out of Edge customers. I sell them all, so I'm not bashing one to sell another.... It seems like the Edge controllers have check features installed. So that when it's increasing the HP/TQ, it's also checking sensors for too much heat, slippage, etc. and will defuel when they get to unsafe levels. The other programmers don't do this.

I have the DP tuner in mine, and I wouldn't switch it for the any other chip. DP only does fords so you get the best programming becuase thats all he does. He gets into shift points, what tires size you have, what gears etc. I don't need a machine to back my settings down, thats why I have analog gauges. Besides if your trans is slipping having it back down is only bgonna make it last just a tiny bit longer. I have heard good things about the edge for the dodges though.

 

[Maverick]

Yeah wouldn't 22mpg be nice..... but 11 is still pretty low, I'm wondering if your injectors are partially plugged.
Oh, and 2,000 RPMs is the magic number on all the diesels (powerjoke, cummins, dmax) for mileage.

If my injectors were partially plugged, would I still get decent mileage on the highway, not towing?

 

[Meat_]

If my injectors were partially plugged, would I still get decent mileage on the highway, not towing?

Sure.

 

[Maverick]

Sure.

Ok, you've got my attention.

What to do? Run stuff through the tank? Recommendations?

btw, only 8 have voted...and only 1 thinks I should go back to 295's. That must have been Carl...or it could have been me. I don't recall which way I voted. I voted the other way at tds.

 

[mbryson]

Ok, you've got my attention.

What to do? Run stuff through the tank? Recommendations?

btw, only 8 have voted...and only 1 thinks I should go back to 295's. That must have been Carl...or it could have been me. I don't recall which way I voted. I voted the other way at tds.

nah, guess again

 

[Meat_]

I'm no diesel man, just throwing ideas out.... I'd try some power service in it, you might clean them up, but most likely they would have to be removed and cleaned or replaced.

I do know that 11 is too low, there is something up.

 

[I Lean]

OK, I voted now...so there's now 3 that say 295's and stop overthinking.

 

[Maverick]

I'm no diesel man, just throwing ideas out.... I'd try some power service in it, you might clean them up, but most likely they would have to be removed and cleaned or replaced.

I do know that 11 is too low, there is something up.

11 would be nice.

It's been 9 since I put the tires on in December. It's also been colder than snot since then.

It was 11 with the 295's. Except when I was in Vernal...not a lot of stop and go.

12-13 with the 285's.

I think with the 265's it was 13-14.

Those are stop & go and/or towing numbers.

During the same time, the freeway mileage has changed very little.

Keep in mind that the X weighs around 9000 lbs.

 

[mbryson]

11 would be nice.

It's been 9 since I put the tires on in December. It's also been colder than snot since then.

It was 11 with the 295's. Except when I was in Vernal...not a lot of stop and go.

12-13 with the 285's.

I think with the 265's it was 13-14.

Those are stop & go and/or towing numbers.

During the same time, the freeway mileage has changed very little.

Keep in mind that the X weighs around 9000 lbs.

WOW...

I'm at about 13-15 daily driving my pickup. It's 7700 lbs, maybe 7900-8000 with the shell and some of the crap that's in the bed at the moment.

I'm thinking you should be getting better mileage than that.

 

[Maverick]

WOW...

I'm at about 13-15 daily driving my pickup. It's 7700 lbs, maybe 7900-8000 with the shell and some of the crap that's in the bed at the moment.

I'm thinking you should be getting better mileage than that.

Well, considering that you have 285's, a chip, and weigh 1000 lbs less than me, 13-15 is consistent with what I got when I had 285's. Pull your empty trailer around in stop and go traffic with your edge turned off, then you'll be me.

I think I had a bunch of 12.6 and 13.1 gas reciepts from back then. I get a reciept every time and write down the mileage, trip, comp mpg, actual mpg, and adjusted for tire mpg.

It'd be REALLY interesting to swap tires. Don't wanna do it unless it's dry though, I want my suction cup tires for the snow.

 

[mbryson]

Well, considering that you have 285's, a chip, and weigh 1000 lbs less than me, 13-15 is consistent with what I got when I had 285's. Pull your empty trailer around in stop and go traffic with your edge turned off, then you'll be me.

I think I had a bunch of 12.6 and 13.1 gas reciepts from back then. I get a reciept every time and write down the mileage, trip, comp mpg, actual mpg, and adjusted for tire mpg.

It'd be REALLY interesting to swap tires. Don't wanna do it unless it's dry though, I want my suction cup tires for the snow.

I'm really shocked how well the Toyo MTs do in the snow. They're WAY better than the Cooper ATs that were on there when I got the truck.

 

[waynehartwig]

I'm really shocked how well the Toyo MTs do in the snow. They're WAY better than the Cooper ATs that were on there when I got the truck.

You're telling me! I was at Home Depot yesterday, and there was a guy pushing snow around with a brand new CTD and Toyo's. He backed up past me after making a run and I kind of laughed about the tire choice, but then he went by again with another full scoop and I had to recant my laughter and watch in amazement.

Keep in mind, we've had blizzard conditions for like 4 days. It snowed almost 2' on Saturday and then rained about 2" overnight and then froze and has been snowing since. So this new CTD was pushing the snow on top of the ice layer. I was out in it today, and there were big rigs stuck all over town. We're not talking about side roads or parking lots, we're talking about stuck on 4 lane highways like State St or Redwood Rd.

 

[Bart]

This thread has me re-thinking my 315s, especially after dropping over $3k this summer on a tranny rebuild. I don't want to do that again.

 

[Meat_]

...especially after dropping over $3k this summer on a tranny rebuild. I don't want to do that again.

If you did it right the first time you shouldn't have to worry about it.

 

[littlesolidkick]

well your milage is probably just about the same. after all your Speedo is off now but if you gear it and put it back to almost factory you'll be all around better on all your drive parts