how well does an IDI tow?

[Diesel JD]

I think the main thing NMB2 did that is allowing him to get away with such high boost levels is to overtorque the ARP studs. He'll have to tell you what that value is cause I don't remember. Also for those that have the skills and inclination to do so, I'm beginning to think that turbo mods or an altogether different turbo is going to be the way to go for a high output IDI. It's been said here before but it bears repeating that the stock turbo kits were designed for stock IDIs with the weak 6.9 head bolts and head gasket issues and folks who were maybe not religious gauge watchers. Since we have overcome these issues and thanks to Mel and Ken we can feed these things more fuel a better turbo and/or an IC or water injection to keep the charge air cool is the next step. An IDI at 15-20 psiG of cooled boost would be very different from any stock or simple turbo truck. On the other hand, if killer HP is not what you need the gear spread is probably a really good issue to look into as RLDSL said, the old Semis took care of much bigger loads than any of us will ever haul with less HP than a PSD. For instance I've seen some ATHS member restored B-61 or B-59 Macks running 237 HP NA or 262 turbo Cummins V8s at the same time they did have 15 to 20 forward gear choices to get over the hill. Not sure if those HP numbers were RWHP or at the flywheel.

 

[RLDSL]

For instance I've seen some ATHS member restored B-61 or B-59 Macks running 237 HP NA or 262 turbo Cummins V8s at the same time they did have 15 to 20 forward gear choices to get over the hill. Not sure if those HP numbers were RWHP or at the flywheel.

THose engine hp ratings are at the flywheel factory numbers. They put them in too many different combinations to try and rate them for each rig they plop them into . If they had tested each one and gave a wheel hp figure it would REALLY be amusing The friction losses after going through 2 boxes with those monster gears and a series of driveshafts gets right on up there, add to that the rotating mass of the diff and resistance of the gear oils and it's like dragging a friggen anchor before you even hookup a trailer that's providing the thing isn't setup for heavy haul like teh rigs setup for pulling lowboys and only has teh single countershaft boxes, The ones with the dual countershaft boxes have so much friction loss it's not even funny.

 

[NMB2]

For towing , going balls out on fuel mods isnt going to be the catch all for getting you over the hill, it just builds more heat after a point when you have a big load on.

I have little experience in gear splitters, however that would be a very good addition to an underpowered engine.

Here is my point.... I have no gear splitter, and 98% of the other light duty trucks on the road do not either. I can approach a grade in 5th gear doing 75mph and never come out of 5th. I have come out of 5th gear one time, and that was going through pass in colorado, I dropped into 4th and was only able to do 60mph. Thats with my 7000lb truck, 1000lbs of fuel, and 7500lbs behind me.

I agree that just thowing more fuel at the engine will not make it a tow beast, I think everybody knows that, but throwing more fuel AND more air at it is the solution. I cant make my truck go over 1200* on the pyro, thats balls to the wall with a load 5th gear up hills holding the pedal to the floor for a decent period. By the time I have to back out due to EGT's.. Im doing almost 90mph... I dont need to do 90mph... just 65-75.

I think the main thing NMB2 did that is allowing him to get away with such high boost levels is to overtorque the ARP studs. He'll have to tell you what that value is cause I don't remember. Also for those that have the skills and inclination to do so, I'm beginning to think that turbo mods or an altogether different turbo is going to be the way to go for a high output IDI. It's been said here before but it bears repeating that the stock turbo kits were designed for stock IDIs with the weak 6.9 head bolts and head gasket issues and folks who were maybe not religious gauge watchers.

My gaskets and overtorqued head bolts are exactly why I can run 20+psi without flinching. In the future I plan to bump it up closer to 30, but I think that is about the max it will reliably handle.

Also, the turbo kits for these motors pretty much suck. The best kit is the ATS 093. It is a T03 comp side, with a T04 center and hot side. This allowed me to swap to a T04z comp side with a 4" inlet, 2.5" outlet, 66mm inducer and 83mm exducer.

On one more note, I get what is being said about the old trucks and splitters, ect. However, I don't just hope to "make it over"... I want to easily make it over. If I start getting passed by everyone and their mother, and especially other rigs towing... its time to get rid of my truck, and get something with more power.

 

[Diesel JD]

Hey all people have different goals. I'm quite happy driving at 60-65mph and let the fast drivers go around me if they want to. I can't afford to keep up with traffic on the prominent roads I've been on (I-75, I95) too many tickets, high insurance all that. I'd like to have the power to do whatever speed I want to though and use it only rarely. Having said that, making it over the hill easily is a good goal and you certainly have achieved that. Your build was really quite good and it's great to have your input here. I think with the IDI engine the first limiting factor was the head gaskets/bolts, and now we have overcome that, the next weak point might be the wrist pins. Not sure if they are really going to be a problem or not. I also wonder if someone could run a built engine like yours 300K miles or much more without an overhaul like a stock or mildly modified 6.9, 7.3 or OBS powerstroke. There could be a compromise but it might well be worth it if the engine still achieves a reasonable service life and doesn't leave you stranded in a bad place or without warning.

 

[Black dawg]

I have little experience in gear splitters, however that would be a very good addition to an underpowered engine.

Here is my point.... I have no gear splitter, and 98% of the other light duty trucks on the road do not either. I can approach a grade in 5th gear doing 75mph and never come out of 5th. I have come out of 5th gear one time, and that was going through pass in colorado, I dropped into 4th and was only able to do 60mph. Thats with my 7000lb truck, 1000lbs of fuel, and 7500lbs behind me.

I agree that just thowing more fuel at the engine will not make it a tow beast, I think everybody knows that, but throwing more fuel AND more air at it is the solution. I cant make my truck go over 1200* on the pyro, thats balls to the wall with a load 5th gear up hills holding the pedal to the floor for a decent period. By the time I have to back out due to EGT's.. Im doing almost 90mph... I dont need to do 90mph... just 65-75.




My gaskets and overtorqued head bolts are exactly why I can run 20+psi without flinching. In the future I plan to bump it up closer to 30, but I think that is about the max it will reliably handle.

Also, the turbo kits for these motors pretty much suck. The best kit is the ATS 093. It is a T03 comp side, with a T04 center and hot side. This allowed me to swap to a T04z comp side with a 4" inlet, 2.5" outlet, 66mm inducer and 83mm exducer.

On one more note, I get what is being said about the old trucks and splitters, ect. However, I don't just hope to "make it over"... I want to easily make it over. If I start getting passed by everyone and their mother, and especially other rigs towing... its time to get rid of my truck, and get something with more power.

do you have any cooling issues?

 

[NMB2]

Hey all people have different goals. I'm quite happy driving at 60-65mph and let the fast drivers go around me if they want to. I can't afford to keep up with traffic on the prominent roads I've been on (I-75, I95) too many tickets, high insurance all that. I'd like to have the power to do whatever speed I want to though and use it only rarely. Having said that, making it over the hill easily is a good goal and you certainly have achieved that. Your build was really quite good and it's great to have your input here. I think with the IDI engine the first limiting factor was the head gaskets/bolts, and now we have overcome that, the next weak point might be the wrist pins. Not sure if they are really going to be a problem or not. I also wonder if someone could run a built engine like yours 300K miles or much more without an overhaul like a stock or mildly modified 6.9, 7.3 or OBS powerstroke. There could be a compromise but it might well be worth it if the engine still achieves a reasonable service life and doesn't leave you stranded in a bad place or without warning.

Well... I just kicked over 10k miles an no major issues so far. Keep our fingers crossed.
As for the wrist pins, back when Ken and I were extensively talking about all of this, he said that the 6.9 rods and wrist pins will pose no issue as long as I run a 3400rpm or below gov spring.

I didnt mean to imply that 65mph isnt fast enough, all I've been trying to say is that some people steer away from an IDI because they arent known to do 65mph up grades with a load behind them. Mine does... and it wasnt all that expensive to make happen.

do you have any cooling issues?

I did early on but it turned out to be a clogged radiator. I have since put a new water pump in, a brand new aluminum radiator, and a Hayden fan clutch spec'd for a 94 F-superduty T-IDI

 

[Diesel JD]

No offense taken, Justin. One more thing, do you mean to say that a fan clutch from the F-Superduty is any different than one for any other IDI? The aluminum radiator was a very good idea. I will probably upgrade to one of those next time I replace mine.

 

[NMB2]

yes, the f-superduty clutch is different.

 

[snaponprofile]

I'm not interested in pulling my heads anytime soon - my motor is young at 107K and she just got broke in. After intercooling, I plan on just leaving the waste gate set at 13-14psi so my HG's stay intact. I mean what more do you need after 10 psi intercooled?, to me, that is plenty. I actually think I'll be lucky to make over 14 psi intercooled anyway, I will most likely hit that only when towing heavy loads(over 10K trailers). Although, power is addicting

 

[93_444idi]

what is special about a f superduty fan clutch? i know where a stick shift f SD has been sitting in a salvage yard for a long time, if it's worthwhile to swap i'll pick it up

and what did your aluminum radiator run you? i'm buying a new radiator soon, but the best price i can find is a copper one for 300 at rockauto

 

[RLDSL]

yes, the f-superduty clutch is different.

Not too sure who gave you that information but Hayden and all it's subsidiaries ( imperial and 4 seasons ) all have the exact same part number for all of the 94 IDI diesels fan clutches. THere is a different part number before the middle of 92. In the middle part of 92 that is when teh 93 year model came out with teh turbo models and all of them were upgraded to teh heavier duty fan clutch and the old fan clutch was ditched so all of the mid 92 and later have the heavier fan clutch .

 

[wmoguy]

no disrespect meant, but those "towing" in the East, or South; I think most who HAVE "towed" in the Rockies or the Sierra's would consider that "towing heavy" I've driven all over the South and Northeast. Their mountains are what we call hills.

that said I'm anxious to flog my IDI once all the work I want to do is done. My goal is to build a "hoss" that can reasonably keep up with families newer Diesel trucks but be cheap to run like mine. I know, "wants to have his cake and eat it" RLDSL is right though, it's about gears. I REALLY want to get some sort of a gear splitter like he has, except I'm not keen on having a secondary shifter in the cab (unless it's driven by air )

 

[RLDSL]

no disrespect meant, but those "towing" in the East, or South; I think most who HAVE "towed" in the Rockies or the Sierra's would consider that "towing heavy" I've driven all over the South and Northeast. Their mountains are what we call hills.

that said I'm anxious to flog my IDI once all the work I want to do is done. My goal is to build a "hoss" that can reasonably keep up with families newer Diesel trucks but be cheap to run like mine. I know, "wants to have his cake and eat it" RLDSL is right though, it's about gears. I REALLY want to get some sort of a gear splitter like he has, except I'm not keen on having a secondary shifter in the cab (unless it's driven by air )

Most folks opt for the turnkey splitters like the US gear ( preferable) or the Gear Vendors splitters that are electrically shifted and don't have the high learning curve.

I spent about a week and a half bouncing around Colorado last fall and I had a blast crawling around those mountains. My beast went as fast as I'd want to take any of those curves ( and I used to have a Kenworth that would do 118 loaded, I'm no old *****
My combination is quite a bit heavier than most for a 5th wheel, I have a real old 5er and that sucker has all wood and steel framing at roughly 18400 that's a good pull running around there in the tourist areas at high altitude. The old girl never skipped a beat . Without the trailer I was up over 13000 ft on some old jeep trails where the air gets pretty thin, but the truck ran great ( I had a pounding headache from altitude sickness, but the truck didn't mind it

While there on a mine tour, I had the pleasure of talking with the tour guide for a while and turned out he used to drive a heavy wrecker for a few years around there and I nearly fell over laughing when he told me that all the time they used to get calls from folks with brand new pickups and trailers stuck on those passes and they couldn't get over! Their dealers out in middle america had told them that, oh yea their 3/4 ton with the real tall rear end for fuel mileage and the slushbox will pull that monster just fine, and then they get to Colorado and stall out on a hill too steep to get up and They'd have to call for a heavy wrecker to haul them clean back out to the flat lands

 

[wmoguy]

Most folks opt for the turnkey splitters like the US gear ( preferable) or the Gear Vendors splitters that are electrically shifted and don't have the high learning curve.

I spent about a week and a half bouncing around Colorado last fall and I had a blast crawling around those mountains. My beast went as fast as I'd want to take any of those curves ( and I used to have a Kenworth that would do 118 loaded, I'm no old *****
My combination is quite a bit heavier than most for a 5th wheel, I have a real old 5er and that sucker has all wood and steel framing at roughly 18400 that's a good pull running around there in the tourist areas at high altitude. The old girl never skipped a beat . Without the trailer I was up over 13000 ft on some old jeep trails where the air gets pretty thin, but the truck ran great ( I had a pounding headache from altitude sickness, but the truck didn't mind it

While there on a mine tour, I had the pleasure of talking with the tour guide for a while and turned out he used to drive a heavy wrecker for a few years around there and I nearly fell over laughing when he told me that all the time they used to get calls from folks with brand new pickups and trailers stuck on those passes and they couldn't get over! Their dealers out in middle america had told them that, oh yea their 3/4 ton with the real tall rear end for fuel mileage and the slushbox will pull that monster just fine, and then they get to Colorado and stall out on a hill too steep to get up and They'd have to call for a heavy wrecker to haul them clean back out to the flat lands

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

 

[NMB2]

what is special about a f superduty fan clutch? i know where a stick shift f SD has been sitting in a salvage yard for a long time, if it's worthwhile to swap i'll pick it up

and what did your aluminum radiator run you? i'm buying a new radiator soon, but the best price i can find is a copper one for 300 at rockauto

After my military discount, it was like $377.

Not too sure who gave you that information but Hayden and all it's subsidiaries ( imperial and 4 seasons ) all have the exact same part number for all of the 94 IDI diesels fan clutches. THere is a different part number before the middle of 92. In the middle part of 92 that is when teh 93 year model came out with teh turbo models and all of them were upgraded to teh heavier duty fan clutch and the old fan clutch was ditched so all of the mid 92 and later have the heavier fan clutch .

That is correct. I guess I wasn't specific enough. Although my local parts store listed the old fan clutch number for the 93.

no disrespect meant, but those "towing" in the East, or South; I think most who HAVE "towed" in the Rockies or the Sierra's would consider that "towing heavy" I've driven all over the South and Northeast. Their mountains are what we call hills.

I am from Washington state and new mexico. I have towed plenty of real grades and hills, and agree... the stuff in the south is nothing.

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.