2nd Gen Non-Engine/Transmission Gears and the highway-anyone?

[Lsfarm]

Keep your gears

High Miles, I would recomend keeping your 3. 55's I believe you can tow very comfortably with them with a few items done on your truck. And you won't be spending as much money and having to live with the 4. 10 gear's rpms and lost fuel mileage.



First: Have you taken care of the KDP?? I didn't see it in your signature. Check the Sticky note in the 12v forums for the info on the KDP.



Next: when doing the KDP have the timing bumped to 15. 5-16*. This will help with HP in the 1800 and up rpm ranges, and make the truck run better when started cold.



Then: Forget the injectors, you don't want to get to the point where you have to back off to keep EGT's under control. You can get plenty of extra HP with a plate alone.



Recommended: install a 3GSK kit, this will allow you to make power all the way to 3000 rpm, and allow you to pull 65-70 mph in third locked if you need to to pull a long, steep hill [with lower EGT's]. Without the 3GSK, the engine starts to defuel at around 55-60 mph in 3rd and you will not be able to get more power above this rpm even with injectors and a fuel plate.



Recommended: Install the 3GSK, and move your stock fuel plate full forward, and take the truck for a trial pull, you may be surprised at the results. If this is not enough power, then move up to a mild fuel plate. Again, you don't want to get to the point that you have to back off for EGT control. Make sure you install Guages!!



As for 'overheating' if your temp guage goes to slightly above the middle mark [around 190*] and stays there you are oK, at 190* the engine is able to dump more heat into the cooling air, and this is a good thing. [more temp difference from cooling fins to air temp] BUT check the radiator, intercooler and A/C condenser for accumulated bugs and crud plugging the cooling fins, this is a VERY common problem and if often the only thing wrong with the cooling system.



If you were at my shop, I'd pull the radiator, clean the cooling fins, if it looks cruddy inside, have it cleaned. While the radiator, shroud and fan are off, pull the front cover, kill the dowel pin [KDP] before it kills you, bump the timing, and then move the plate, and install the 3GSK. This will make a vast improvemnet in the towing performance of the truck. And the truck will run very nice when empty.



I have done the exact above items and cured a truck that couldn't pull a 5K toyhauler, and now it pulls 10K easily. And the EGT's are under control.



Once you are done with the heavy hauling then add the injectors if the HP bug bites you and have even more fun.



Hope this helps, PM if you have questions.



Greg L

 

[Bart]

Greg L. Maybe I missed the boat on something. I had a fuel pump plate installed (one of the few things I didn't do myself). I'm not sure what size it is and can't check until Tuesday, but I think it was a #11, again not sure. I looked at the installation instructions from TST but no mention of the size.

Anyway that's all I did/had done. No timing change or anything else you mentioned. I too have been thinking about going to the 4. 11s but if I could get BART (Big ***** Red Truck) to do more without changing the gears I'd be interested. As a rule I drive around 65 mph (1750 r's). Most of the time I tow heavy, around 16K#. That includes a cab over camper (so it's tall). In this article I saw someone mention moving something 15-20 clicks. What was that? My truck has 150K on it and does okay power wise It has the ATS transmission, 3. 54 limited slip 80 in the rear and 235 tires. My aim is power and fuel economic. The only way I know to attain that is to slow down. I don't accelerate fast and 65 is the norm on the highway unloaded and 60 loaded. That puts me right around 1600 r's which I understand is in the power band. As a rule the only time I need to get out of o. d. is if the egt's get too high (1200 max). Then I slow down to 50-ish and 900* and just over 2,000 r's. Your thoughts please As a side note I had a K&M air filter in a stock air box but removed it after reading the Cummins site about them. Signature isn't showing up so I'll run it again. 1998 12V auto (ATS) 4x4 dually with 3. 54s and 235 tires. Pretty much stock except for trans, and fuel plate from TST. What's this GSK?

 

[Lsfarm]

Gsk

Hello Bart, the GSK is a Governor Spring Kit. It is a set of new governor springs and spring seats that change when/where the injection pump starts to defuel to control HP and rpm.



The stock 98 will start to defuel around 2400 rpm and pretty much stop revving under load at around 2600 rpm. Every truck is different, some defuel sooner, some later.



With a 3000 rpm governor spring kit installed [3GSK] the engine will continue to pull strong and not defuel till around 3000 rpm, this gives an additional 4-500 usable rpm, right where you need it if you are trying to hold 60-65 mph in 3rd gear [direct].



With your driving speeds and towing weight, you may need to go to 4. 10's but for the cost, I'd surely try a 3GSK first to see if it does the job for you before spending the cash on 4. 10 gears.



You can safely run your engine continously at 2600-2800 rpm in 3rd gear, the egt's will be lower and often the fuel mileage is the same or better with a lighter loaded engine at higher rpm compared to a heavily loaded [almost lugging] engine at lower rpm.



Give some of your local 12v guys a PM or local shop a call and see if someone can walk you through the install, it seems pretty daunting at first, but it is pretty easy if you go through the side of the pump, not in from the top.



The 'clicks' mentioned are for the star-wheel in the AFC housing, this helps add fuel earlier, helps spool the turbo sooner, but does add some smoke untill the turbo developes boost, maybe not something you want to have.



Hope this helps, Greg L



PM with a phone number if you want to chat. Greg

 

[biggy238]

I read thorugh some (most) of the posts. On the 96' truck, I firmly agree with LSfarm. Add some power and you shouldn't be any worse for wear. I would do as he said, Gauges, 3kgsk and a slightly taller tire size.



You should be able to pull 60mph in od at about 1700rpm (guessing here) and have enough power to climb those hills (sound more like mountains to me)



Stock, my truck didn't have a chance at getting up a good hill in od. I got gauges and slid the plate enough to suit my. I have a consistant 17mpg and 20 interstate, where as my numbers were lower before. I was spending so much time unlocked and winding the motor that I was wasting fuel.



Someone else asked if the trucks could be calibrated electronically to correct the speedo for tire size. Yes, and no. On the 96 and I think 97 pcm, you can calibrate for the two factory option tire sizes only. However, You can do a little math and come up with the gear you need. Mine is within 100ft. the mile.



Again, keep your gears and add power. In the long run you should be able to even out your fuel consumtion by spending less time on the hills behind traffic and more time in the flats at the speed you want.



I also suggest you check your fuel pressure. If your truck is running on low pressure, you are going to keep your foot in it undue amounts to provide the same results.



Good luck.