how well does an IDI tow?

[RLDSL]

Is there any brownie box thats a single shaft that is pneumatic that would work for our application?


Yea there are some doozies out here in Colorado. One of the ones I think is really tough is I70 right outside Denver. If you are getting off C470 to I70 headed west you get dropped RIGHT at the start of that grade that goes for something like 15 miles. Its brutal. I've riden or driven some hopped up Cummins that even struggled (more EGT issues than anything) to make that pass without slowing way down.
I think the TRUE test of a good puller pickup is how it rebounds after loosing momentum. Most rigs with some power do great so long as no one cuts them off or they take a switchback and lose all their momentum. A truck with the right gearing and power can rebound after a momentum loss, not leaving the driver cussing like a drunken sailor when someone cuts them off on a long grade when they are loaded down

That's no joke, Eisenhower and grades like that gets everyone crawling. You're quite right. It doesn't matter how much power folks have on hills like that about a third of the way up, heat is the great equilizer and everyone who is loaded down hard is all crawling at about 20-35mph. You are quite right about recovery I noticed a few times some of those new fancy trucks barreling past me near the bottom of some grades where it was fairly straight but when they had to nail the brakes for the curves, they were darn near dead in the water and I was right up on their tail in no time having to back out of it and wait on them while they billowed black smoke and went nowhere It's obvious youve spent a LOT of time driving around in those mountains
YEs there are some single countershaft brownies that are air shift, but finding one is near impossible. I looked for over a year to try and find one because I wanted one so my wife would be able to drive it easier . The RP 8000 series is air shift for sure they are 4 speed air shift brownies. any of them with P in the number designation are air shift ( P for pneumatic shift ) but the 1241p is a twin countershaft ( got to remember the only one that has been built in the last 40 years is the 1241p. With the demand down and scrap prices high in the last few years the ones that were laying around got turned into toyotas, there's only a few wrecking yards in places like Oregon and Michigan where they have a history of heavy hauling where the things still regularly pop up)
Of course, you could always go nuts and ditch the adapter ring on teh back of teh engine and use an sae bellhousing and pop a spicer p-8500 16 speed combination box on there that is basically a 4 speed with a 4 speed air shift brownie attached directly to it . THey had this really nice 4 notched air shift handle. They actually had a 4x4 and a 5x4 version of this , it was also known as an SST at one time

 

[RLDSL]

I actually was just having a convo about gears with F100SWB (evan) the other day, and I was telling him my gears are a bit too close together 1-4 with 4.10's I dont know if the IDI ZF5 is different than my PSD ZF5, but I really dont think I could use a gear splitter. I get through 1 - 4 so quickly, there would be no room for in the middle. Something between 4th and 5th I could probably use though on big grades.

The key to a splitter is getting the engine in the range where IT pulls the best.
When towing heavy on the interstate I've found that 4 over is the sweet spot at about 62 mph. Yes, if I really wanted to I could shove it up into 5 over and drag it along at 75-80, but I really don't care to have to look over my shoulder all teh time and it drops my fuel mileage in the toilet near around 8 mpg, where at 62 in 4 over I get around 14 and it pulls so well there that I almost never have to shift. Before I got teh brownie on a trip from Little Rock to Dallas I would have to shift back and forth from 4th to 5th non stop, 4 would be screaming , and I'd finally get enough going and 5th would pull a while and bog downand end up on another up stretch and have to drop again. Now I can slip in into 4 over and leave it there the entire trip aside from one river crossing and get better fuel mileage in teh process. When in teh mountains youd be surprised how easy it is to grab a half gear from second on up. It takes the hard load off the engine and makes it easier to grab the next gear.
I've got 15 gears and I use every last one of them . It makes life easier , not harder. THose low range gears are sheer joy for poking a trailer into a tight uphill spot or getting back out and save a LOT of wear on the clutch

 

[johnnyb1]

RLDSL, you said it!! Gears,gears,gears. My first heavy truck was cranked 400 Cummins,13 and Brownie. That's what we had and it worked. My first KW had a C-15 [725 hp.] 18,2 spd. rears. Now I've got a 625, 18 & 2. I don't pull super-loads anymore so why feed extra 100 hp? My point is [ I'm not disrespecting anybody ] "it takes iron to hall iron". Sometimes we ask too much from our trucks. Myself included. Jumping back, are these big Cats gonna last 1,000,000 miles? I REALLY doubt it but they sure are fun to drive. !!