Towing EGT's

[565edge]

I bought a Gearbox Toyhauler model 375's 5th wheel. Its 38' long. I loaded it up last weekend and towed from Bakersfield, Ca. to Las Vegas. I hit the Tehachapi grade on Hwy 58 and the Baker Grade on Hwy 15. Both are long 6-7% grades. My trailer weight is around 14,000. I kept EGT's at 1200 or lower but after a while on those big grades and had to shift down to 2nd gear. I have the 80hp tow and 60 hp tow from DP Tuner. I am sending it off to get his 40 hp and 20hp tow tunes added. Would a 1.00 housing make the egt any better? I have bellowed up pipes and the turbo or innercooler does not have leaks. I ended up pulling both of those grades at 40 mph. Truck does decent on flat ground in overdrive but on the big grades I thought it would do better.

 

[psduser1]

Any tuning?
That, and a different turbo, would go a long ways toward making your setup work.

 

[Jomax]

I used to keep my egts below 1350. Never had an issue. But honestly that sounds about right. 40-45mph up hill.

175/30s woke up my 7.3 where it would pull the same hill at 50-55.


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[565edge]

Truck has a d-66 type turbo with billet wheel. I have dp tunes. From reading I decided to buy a hydra from ******** and got his 6 tunes. Black friday sale $110 off. Heard great things about there tuning.

 

[superpsd]

I would sell off the D66 and go T4 with the SXE or KC turbos SXE style drop in. The D66 has not had the greatest reputation. However see if the Hydra and new tunes help.

 

[565edge]

I installed the hydra and towed last weekend. Truck runs better and tows better but still getting high egt up big grades.

 

[dsberman94]

You’re going to have to watch them. It’s a tuned 7.3. It’s going to get hot on long grades.

 

[blacksmoke.r.us]

What kind of boost is it making when pulling those grades?

 

[dmd]

I have a similar setup, some differences. These are old trucks and not nearly as
refined as the newer ones so you can't expect them to pull like them even modified. You
get slowed down on 2% of your miles with what you have and the trip takes a few
minutes longer than if you could keep speed limit. Truck is much better than stock
with the modifications, I just live with it and relax knowing I have 50K more in my
retirement, and pull the long hills a little slower. I can usually keep the speed
with just dropping out of OD, but if it gets slowed down by other traffic I occasionally
have to drop it down to 2nd. I suspect that is what happens to you.

Before being modded I pulled into Death Valley from the west with a large TT, had it
down in 1st for the top half of the hill and had to stop part of the way up for the
transmission to cool down. Coming down that hill was just about as fun for the
brakes.

 

[565edge]

What kind of boost is it making when pulling those grades?

It will make 15 psi on the flats or slight hill. On the larger grades it makes good boost but I cannot remember exactly. I want to say in the 15-20 psi range. It gets hot when I roll my foot into it. It has pedal left in drive but gets hot so I downshift. Once I down shift I get way our of the throttle and hold it it 2,750 RPMS in 2nd gear. usually around 35-38 mph. I need another gear between 2nd and drive.

Totally agree with you DMD! I just want to be able to hold drive even at 45 mph. I might try a Mishimito Innercooler next then stage 1 injectors.

 

[dmd]

Single shots will help, not sure the intercooler will too much. With the 7.3 you are pushing
it 100% so it gets to the limits. With 6.7 it has lots more HP and Torque so it will be at
65% and still have plenty to go.

I agree, the extra gears sure would be nice, helps stay in the power band. When ours
shift up we fall right out of the bottom of the peak HP range and most of the time
on big hills there isn't enough left to get it back into the power. Your 410 gears should
help, my 373's don't do me any favors when pulling. I have to drop down early if loosing
speed before it would be too low of RPM even in the next lower gear. Honestly the
38r really drops out below 2000rpm. It was the thing to do at the time, better
options for lower end power now but I don't want to spend the cash when 99.9%
of the time it works just fine.

The HPOP, turbo, and the injectors really help. I don't push it though, I want the
truck to last a few more years.

 

[old96stroker]

Pull the 295's off of it when you are towing and run factory size rubber, I bet it would make more than a little difference, I know you probably wouldn't like the looks but it would pull better and handle better also.

 

[ithumpwheniwalk]

What kind of boost is it making when pulling those grades?

It will make 15 psi on the flats or slight hill. On the larger grades it makes good boost but I cannot remember exactly. I want to say in the 15-20 psi range. It gets hot when I roll my foot into it. It has pedal left in drive but gets hot so I downshift. Once I down shift I get way our of the throttle and hold it it 2,750 RPMS in 2nd gear. usually around 35-38 mph. I need another gear between 2nd and drive.

Totally agree with you DMD! I just want to be able to hold drive even at 45 mph. I might try a Mishimito Innercooler next then stage 1 injectors.

It's already been said, but I'll reiterate. Lose the D66. It is not a good turbo to be towing with.

I'm in your ballpark, my 5th wheel loads out over 14k. There's no way I'd dream of taking the trailer on any sort of trip with my d66. I yanked it off, went back to stock, and it was an improvement.

Not ideal, but like people will tell you, the new turbos like the t4 sxe line are a night and day improvement over the older technology. Just my .02 cents, I'll be upgrading both injectors and turbo for this towing season.

 

[04cr450]

Agreed^ when i put 35's on the 6.7 i can spike the egt gauge running light on a hot tune... the 6.7s run hot also when towing - im impressed with you're 7.3 lol

 

[565edge]

I'm going to look into a different turbo. Being in California I'm stuck with my options. I would love to do a t4 mount set up but I do not know a smog guy. I plan on doing injectors and wait on the kc turbo 38r 366. Some guys really like water injection. Been looking into that as well. I have diesel site intercooler boots and plenum boots, bellowed up pipes and the plenum inserts from riffraf that let you tighten down the clamps more on the heads. Ordered a boost leak detector and will check for leaks this weekend.

 

[Dan V]

Putting 1.0ex housing would help the EGT, but it's gonna get laggy.

 

[565edge]

I see everyone does not like the D-66 type of turbo. What I have a hard time understanding is my truck does not smoke. It will only puff a little smoke in the highest setting if I stand on it from a dead stop. Other then that it does not smoke. It seems like if it is laggy it should smoke right?

 

[Sterling B.]

I've never got above 1200* with 315s and 26K in tow; 363K miles on original injectors (1 reman), built trans, 6637, original turbo, DP Tuner on 40 hp tow, and 5" exhaust.

 

[dmd]

Yea, I mean you have to also come down to you have a 17yo truck and it isnt gonna
do what the new technology can do.. You can always upgrade to a 6.7L and be
faster up the hills. Just do what you can with what you have.

My 38r is old school even for the 7.3, but it was the best thing around when I installed
it. It completely drops off around 2000rpm and I have to shift down, but if I can keep it
above 2100 it will climb a wall. I regularly drop out of OD and get the RPMs up and
and run 60MPH up most hills.. Now if I get slowed down I am dead and have to shift to 2nd.. I almost made it to the top of Tehachape (right by you) pulling my TT the last time I ran it until I couldnt get around a slow truck... Then 40 or so the rest of the way.

 

[565edge]

I went off the deep end and bought 238/80 injectors from unlimited diesel. Bought a set of comp cam 910 valve Springs and shim kit. Going to buy smith brother pushrods next week. Not sure if I'm going to put studs in it at this time. Hopefully Gear Head can turn it down in the tow tunes and make it run cooler. Not sure if I should put on a 1.0 turbine housing now or wait until I see what happens with egt's. I think I'll wait and if it still has high egt's I'll do anot her turbo down the road. I'll be pulling injectors tomorrow to send in for my cores.