Forum Discussion
- How much torque will a towing tune give you?
ShinerBock wrote:
4x4ord wrote:
A clutch can’t take the kind of torque that can fed into the new automatics ..... Back in 93 with my 6.5 turbo diesel and manual transmission I got stuck in a snow drift with a heavy trailer on behind . I ended slipping the clutch with only 400 lbft of torque .... I didn’t realize it until the cab startled filling with smoke. I think a tuner could cause you more grief than it would alleviate.
Stock clutch, no. However, there are aftermarket clutches available that can. One of my hot shot friends has a South Bend dual disc rated at 650 rwhp that did not cost that much more than the OE clutch replacement. If I am not mistaken, he has had it in the truck for at least four years now and is still going strong. I know he is pushing at least 100 rwhp over stock. South Bend makes them up to 950 rwhp for the G56, but they are pricey when you start getting that high of power levels.
The Southbend dual disc in my truck is good for 550/1100 and 30k towing so I think it will handle a towing tune just fine.FishOnOne wrote:
I'm sure tuning, transmission design, engine design, gears, truck weight, aerodynamics, are all designed in to meet certain goals (i.e. EPA, NHSA, Cost, Customers X,Y,Z) and good market research to set these goals produces a better product.
I can honestly say my '12 6.7 PSD with 400HP makes better fuel economy towing/non towing vs my '05 6.0 PSD with 325HP. Towing performance is much better and neither truck derated power when towing mountains during summer months.
In the end I would much prefer the 400HP of the 6.7 with the improved fuel economy I get, vs having a 6.7 with 325HP (same as a 6.0) with even more improved fuel economy.
You and my father in law are on opposites sides. He felt that his tuned (lowest level "tow" tune only) 2003 F350 6.0L towed better than his 2019 F350 and got slightly better fuel economy. He said the stability is better in the 2019 and so is the trans. Seeing that his 2019 F350 is around 1,500 lbs heavier than his 2003, it kind of makes sense because it takes a lot more horsepower to achieve the same acceleration in the heavier truck. Even a slight 50 hp bump in power would give the 6.0L the edge even to a 450 hp 2019 F350. Of course these are short burst numbers and not sustained numbers.
I also now for a fact from gauge data that both his 2019 and my brothers old 2012 F350's derated/defueled under heavy sustained conditions when towing. It is very gradual and hard to tell unless you have a very sensitive butt dyno. Like those people who swear they can feel the difference in power from a "performance" air filter. However, the gauges and commanded fuel pressures don't lie. Neither do the defuel settings in the ECM that are easily seen with SCT software.- I can say after driving my Sons deleted 15 SRW 3500 AISIN its faster in tow tune even towing 24k combined than my stock 15 DRW AISIN solo. It simply feels nimble.
- We’ve deleted our Kenworth and blocked off the EGR. The thing still has no over abundance of cooling. The same can be said of our pre emission Peterbilt. A hot day and long hard pull can get these trucks to the point of red warning lights. I was under the impression that removing the emission equipment on the newer diesel pickups doesn’t do much for fuel economy anymore? If it’s true that a Ram pickup has cooling for 500 hp deleted yet only 400 hp stock then 100 extra hp is being lost into the cooling system. So removing the emission equipment without adding any addition fuel would offer a gain of 100 hp. We should be able to do a delete on our trucks and see a 25% increase in fuel economy without attributing anything to the loss in efficiency that the restrictive exhaust is causing. Plus there is the lost fuel used to clean the DPF. All tolled a deleted truck should get substantially better fuel economy. I really would be interested in seeing a before and after deleting fuel economy comparison done. For those who plan on putting 300,000 miles on their truck deleting could save between 10 and 15 grand on fuel over the life of the truck.
ShinerBock wrote:
4x4ord wrote:
^^^^And he said he’s already installed a dual disc clutch ..... so I’m kind of curious what steps would a person need to take to build a reliable, deleted, non smoking, tow unit? Say to get the truck to a USEABLE 400 RWHP. Cummins increases boost and lowers the compression ratio to add power.... Are those mods unnecessary if only adding 120 HP? (But again wanting to be able to use the power while towing) Is a new air to air and radiator necessary? I guess if all you have to do is swap out the exhaust and add a tuner it’s not terrible expensive.
400 rwhp is already usable on the Cummins. In fact, that is exactly the power level that most tuners call their "heavy tow tune" on the Cummins. I know my hot shot buddies generally leave theirs on 425 hp, but they have aftermarket turbos. The exhaust side of the HE351 VG turbo on the Cummins is your bottleneck. It is small and very restrictive so you would have a hard time sustaining higher power levels while keeping EGT's in check.
It is not about adding boost to increase power. It is also about injection timing, injection duration, and injection pressure. Just as it does on a gas engine, increasing these will increase power, but will also increase emissions specifically NOx and PM. Boost is just an after thought on a diesel. Remember, a diesel is regulated by fuel, not air, so the amount of air it is using is determined by how much fuel is injected. It is the opposite for gas engines where the amount of fuel being injected is determined by how much boost(air).
As stated before, the Cummins HE351 exhaust housing is small and restrictive. This is good at quick spool up and keeping power even at higher altitudes, but it is not good if your goal is to achieve the highest power levels possible. It is not just about boost either. Flow also has a lot to do with it. At 15 psi, my turbo is flowing a lot more air than the HE351 turbo is at the same psi. If I recall correctly, the HE351 has a flow of around 60 lbs/min while my turbo is 82 lb/min.
Also, Cummins did not lower compression ratio to increase power so to speak. They lowered it to meet NOx emission while increasing power. They could have kept the same compression ratio and easily increased power, but NOx levels would have been high. So in order to increase power and to keep NOx within regulations, they had to lower compression ratio which in turn also lowers the efficiency of an engine. Hence the reason why the lower output "efficiency" Cummins with 68rfe has a much higher compression ratio of 19:1 versus the high output engine.
You will notice this with all of the big three diesels. As power output increases, compression ratio decreases. The Duramax used to have a compression ratio as high as 17.5:1, but overtime as they increased power, it decreased to 16:1 with the 445 hp L5P. The 6.7L Powerstroke used to be 16.2:1 and now it is 15.8:1 with the added power of the 475 hp 2020 PSD. The 6.7L Cummins used to be 17.3:1 and now it split to 16.2:1 for the 400 hp high output and 19:1 for the 370 hp standard output or "efficiency" engine. Notice one big thing about these compression ratios compared to the HP outputs of each engine?
So those who say that they wish the engine makes would focus on efficiency rather than power do have a point. The more power they add, the less max efficiency potential the engine has due to lowering the compression ratio in order to stay NOx compliant at that power level. This loss in engine efficiency can be made up in other ways like gearing and so on, however, you are still losing max potential efficiency by wanting more power on a stock truck that has to be emissions compliant.
I'm sure tuning, transmission design, engine design, gears, truck weight, aerodynamics, are all designed in to meet certain goals (i.e. EPA, NHSA, Cost, Customers X,Y,Z) and good market research to set these goals produces a better product.
I can honestly say my '12 6.7 PSD with 400HP makes better fuel economy towing/non towing vs my '05 6.0 PSD with 325HP. Towing performance is much better and neither truck derated power when towing mountains during summer months.
In the end I would much prefer the 400HP of the 6.7 with the improved fuel economy I get, vs having a 6.7 with 325HP (same as a 6.0) with even more improved fuel economy.- Undeleted, probably won't handle that much power on a long pull, but deleted is a different story. Not only are you removing two large bottlenecks that trap a lot of heat when deleting, the SCR and DPF, but you also remove a component that is very taxing the cooling system, the EGR cooler, which cools the already hotter than normal exhaust gases.
A lot of people think that the grilles and radiators on these trucks started getting bigger because of the power ratings. This is partially false. The 6.4L PSD did not make much more power than the 6.0L it replaced. Neither did the 6.7L CTD over the 5.9L or the LBZ over the LMM yet the grilles on the trucks started to get larger after 2007. Why, because the emissions equipment created a lot of heat under the hoods of these trucks and larger radiators were needed to cope with this added heat. Especially in trucks without DEF/SCR because they utilized the EGR even more. Removing these system on a truck that was designed to handle them frees up a lot of sustainable power potential if the air is right.
Speaking of Kenworth, I remember when PACCAR, the owner of Kenworth and Peterbilt, was in a lawsuit with Horton fan systems shortly after 07 when class 7-8 trucks required these emissions systems as well. You could not keep a Horton fan clutch on one of these truck longer than six months because the bearing would just explode. I had a lot of pi$$ed of customers because of this.
PACCAR and Horton thought it was a bad bearing supplier so PACCAR switched to Borg-Warner to supply their fan clutches. Lo and behold, they started failing the same way too. It was shortly after this that PACCAR(and all the other makes) figured out that it was all of the extra heat from the emissions systems on these trucks that was causing the bearings to fail. They started making trucks with even larger radiators(similar to what the light HD trucks did) and dual bearing fan clutches to handle the added heat. - Oops.... I didn’t mean to be antagonizing. Shiner has been pointing out that these trucks can’t sustain the factory power ratings and I can agree with that. So I was just curious what it would take to get them to a higher level...... I was not expecting the response he gave. In my opinion these trucks don’t have cooling systems in place to capable of handling an additional 120 hp. When you compare the aftercooler and radiator on our Kenworth with the after cooler and rad on a Ram it’s hard to imagine that the Ram can make more useable power than the Kenworth.
- And the antagonism continues with 4x4ord!
Winter gettin long already up there or what?? - I will also point out that in general emissions that are bad for the environment like CO2, HC, and CO decrease dramatically with higher compression ratios. However, due to the US EPA's hard on for NOx ,which is only harmful to people in very heavily populated areas and is not an issue for those who don't live in areas with a population of 2 million people. US diesel owners have to suffer in added complexity, lower fuel economy, worse environmental emissions, less reliability and so on to keep NOx low so people can live in metro areas with very large populations just in case we might drive in there.
