Engine/Transmission (1998.5 - 2002) Need to detune from sled puller to trailer puller.

[BILLVO]

I am at a cross roads right now. I want to still have a fun rig to run but the current turbo injector and gear ratio combo doesn't work at all for a daily tow rig.



I have BD 155 hp injectors and an II silver 62 turbo which contrary to II's bragging isn't a good tow turbo with 3. 54 gears and an auto trans. I would like a smaller set of injectors like 90 hp but don't know where to go with size on my turbo.

I am thinking an II sps62 or sp62 but other than the BD super B I ran which was a bit too small for my wants I am not sure what way to turn. I want to be able to pull at least 8k in OD with no egt issues. Most speed limits around here are 65-75 and to keep my egts in check while towing I have to run with OD off and the Rpms are way to high for my liking at 2500 at 60mph even for fuel econ ect.



I have a full set of gears to go to 4. 10 but would rather that be a last resort.



Anyone have any ideas what would work best for my needs. I want to still sled pull but need it to be better suited for daily towing.



I am throwing it out if someone wants to do a swap for a different turbo injector set up I am open to offers.

 

[jgillott]

Are twins out of the question?

 

[BILLVO]

Spending as little if any as possible is the goal. I spent a boat load getting to hear and don't want to spend a boatload more to go backwards. That is why I am open to trade deals. I may call II and see if they will work with me But I hear they usually charge next to new prices to do changes.

 

[fox]

Don't change the gears.

Drop injectors to 50-90 hp and use a hx35 /14 waste gated turbo.

 

[Cummins724]

Billvo, I know you have a automatic, but the combo I run tows 18k# like a dream. If it is a hot day, I can set the ADR to defuel & keep egts below 1250*. I don't think that you need to change the turbo. I think you need to get a box that keeps the egts in check so that you don't have to. Then swap that HRVP for a SO pump & you'll be set. I've tried dozens of combos & also have friends with tow rig autos. Just my $. 02

 

[BILLVO]

The problem is the silver 62 is a 62-74-14 versus the normal 71 and I think it is the laggy culprit that needs to be taken out along with the big injectors. I know of others running the sps62 with 90 hp injectors who tow a lot better than I do and are only 30-40 hp lower and more torque than I have. If I can get an earlier spooling turbo I believe it would make a big difference. In my current setup the HRVP actually helped the egts and I like the puch it gives me.

 

[DCreed]

I'm running 250hp injectors with a 3:54 auto and ADR and 3rd gen 62/65/12 and have no major EGT issues towing our horse trailer @ 4500lbs. but I run with timing up and fueling down. I do think you would be better with a 62/71/14 than the silver on a VP truck, JMHO.

 

[Cummins724]

The problem is the silver 62 is a 62-74-14 versus the normal 71 and I think it is the laggy culprit that needs to be taken out along with the big injectors. I know of others running the sps62 with 90 hp injectors who tow a lot better than I do and are only 30-40 hp lower and more torque than I have. If I can get an earlier spooling turbo I believe it would make a big difference. In my current setup the HRVP actually helped the egts and I like the puch it gives me.

Very possible. I've never run a 74 turbine. I still like the 64/71/14 better than the 62 though. It is only 50rpm slower than 62, but cools it down fast.

 

[BILLVO]

The more I think about it the more I am leaning towards doing a gear swap to 4. 10 rather than detuning for now. I think it will be beneficial for both towing and pulling with my current setup and I have all the parts needed for the ratio swap.



Thoughts or comments welcome



My question for those with 4. 10 gears is what rpm is your rig running at around 70 mph in OD?

 

[GHedger]

you will be in the 22- 2300 rpm range

 

[DCreed]

The more I think about it the more I am leaning towards doing a gear swap to 4. 10 rather than detuning for now. I think it will be beneficial for both towing and pulling with my current setup and I have all the parts needed for the ratio swap.



Thoughts or comments welcome



My question for those with 4. 10 gears is what rpm is your rig running at around 70 mph in OD?

what size tire (dia)??Oo.

 

[BILLVO]

what size tire (dia)??Oo.

At present I am running bfg kmII 255-85-16 so 33. 1 inch dia but may switch back to 265/75/16 in future.