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Discussion Starter #1
Bought a toy hauler this morning. It weighs 6200# empty. It is by far the heaviest load I have pulled with this truck since I lifted and went to 35's. I usually just pull my boat which is about 1900#. You can see my mods in my sig.

So, here's my dilema. Towed the hauler home today. At 60 mph, I was pulling 9 lbs of boost, 900 EGT at 2500ish RPM's with OD off. I did not push it any harder as it normally runs 1900 at 70mph empy. This was on relatively flat straightaways. If I switched to OD my RPMS would drop to 1600 but my EGT's jumped to 1200ish staying at the same 60 mph. Needless to say, I did not run like that but a few seconds.

My simple mind believes my problem is gearing. Should I go to 4:10 or move on to 4:30? Am I missing something else I could be doing?

I have been at a miserable 13mpg since I went with the larger tires and dread what these gears are gonna do. But I guess you gotta pay to play.
 

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My last truck had 35's with 3.73 gears and it towed fine. Im mean, 4.10's would have been nice, but were not req'd at all. You should have no problems towing with that weight. Im not sure what a set of gears would cost you, but i'd put the money towards a good towing turbo like the 38R, which will be a great improvement, even with stock injectors.

Check for boost leaks and for soot around your up-pipes to be sure your not loosing any power there.

Also, re-calibrate your speedometer for the bigger tires. At 2000 rpm's in O.D. your really running around 75-76mph.
 

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Its been recalibrated, Im running what the speedo says. And if Im not mistaken there are no turbo upgrades for an early 99.
 

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My bad... Wasnt anything around last time (been awhile) that I looked.
 

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Exhaust temp seems a little high. Just check out all of your intercooler boots. Its been so long since ive had a 'stock' truck, but your boost might be a little on the low side too since your only pushing 9psi @ 60 mph in 3rd while pulling a trailer.

On the street, whats your peak boost under WOT without a trailer?
 

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Discussion Starter #7
I'll have to check that tomorrow and get back to you. Trailer is hooked up right now.
 

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Discussion Starter #8
On the street, whats your peak boost under WOT without a trailer?
With the 80 econo tune I was pushing 24-25 at 90 mph. I let off because EGTs were hitting 1300.
 

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Boost sounds about right for a stock turbo. Try towing in a lower chip setting if you have one.
 

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Get in touch with Jody and get a 20 & 40 tow tune. I have stock tires but My trailer loaded with buggie, water etc. is right at 13K and here in this heat in Az. I can pull 6-9 miles of 6% with egt's around 1200-1300 @ about 60 mph. It's a lot better now that I have the Adrenaline. It helped a bunch and cleared up the smoke by about 75%. Check my sig. You'll struggle more than I because of your tires. My dually is a conv with 3.73's. Good luck.
 

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Discussion Starter #11
I called last week but he was out doing live tunes. The other guy working acted like I was just wasting his time with my questions. He wasn't much help and wouldnt offer any recommendations.
 

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What else?
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You can run 1200* all day without a problem, but as previously said, I'd check for exhaust or boost leaks, and see about getting a towing tune from your tuner.

Dave
 

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I have towed about that same amount but with my X which puts 1K more on. I the only time my egts would hit 1200 was grades where it should have down shifted anyways. On flat ground in a tow tune you should not have egts IMO over 1000. I would first check for exhaust or boost leaks. If its been a while replace/clean the air filter. Given your mpg it also indicates an issue. 13 unloaded is very low unless you drive hard all the time. On the highway cruising unloaded you would have at worst broken even or gained but the width increased so breaking even or a very slight loss is possible.


How was your tranny temps?

Reason for asking: One thing I noticed is your speed RPM at OD and then at 3rd with those tires and gearing is off. This is not to dispute what you saw or the speedo being off ( I don' t think)but may indicate a possible issue:

35" wheels and 3.73 gears

3rd (1:1 ratio) / OD (0.71:1) with converter locked you reported:

2500 rpm / 1600 rpms @ 60mph +/- 2 mph respectively


Working the math your OD numbers add up fine. 0.71:1 changes the rear gears to 2.6483 ( 3.73 x 0.71) 35" diameter wheel. Should be about 62 mph which is well within tolerance.

But when you have OD off and are in 3rd which is 1:1 ratio your speed should have been close 10 mph higher 69-70 something you would not mistake easily on a speedometer.

Your 3rd gear RPMs ratio to speed works out to what would be correct with 4:10s in the rear not 3.73s.

I am not a tranny guy but I would think barring a mis-read this would indicate a converter not locking up fully or slippage somewhere.

Please check my math as I could be off or my brain is taking a crap which happens in grave yard hours. Maybe the speedometer bot being correctly adjusted when it was done could do this? I would've expected all the speeds to be off though.

If what I have done comes out to be correct you may want to try driving again same load a number of different times recording RPM speed going in and out of 3 and OD etc. Then doing the numbers. If there is an issue you may need to get your tranny checked out.
 

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Discussion Starter #14
165 degrees. It was 79 outside.
 

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If you are going to upgrade to a beans turbo I would let beans do a reburn for you. Its their stuff, they have tons of hands on with it, but that's me. I have sigs turned off so i don't know if you have injectors, if not a set of tranny savers or stage 1s would be a great add.


micky
 
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