Travel trailer hill climb test - She got a C-

[Mikey von]

I got my trailer wiring mostly figured out and hooked up to the travel trailer and up the mountain. My trailer is about 6500 lbs as it sits now.

Here is my test mountain. Climbing almost 1500' over a few miles. My buddy pulls it at 40 with his 800+ HP log truck loaded. My wife's half ton 2005 Suburban with HD tow package (3.73 gears and trans cooler) pulls it with our trailer in 2nd at around 38-42 mph.

My Suburban pulled it at 42 mph or so in 3rd. I could spin it faster but when I got on it my boost pegged the gauge out at 15 lbs so I did not push it. Temps were great EGT's between 700-900 depending on how hard I pushed. Just holding 40-42 mph, boost was 11-12 lbs. Water temp held steady at 205, didn't budge. I could get some haze/smoke when I got on it but not much.

4th gear was not happening. It would rapidily lose speed and just billow black smoke. EGTs rose a bit, but I never stayed long enough to find out. RPMs would not climb.

My goal is to pull this grade at 55 mph. I know I am under geared with 4.10s and 35" tires. I want either 4.56 or 4.88, not sure. Then look at bigger turbos and better intake? ATA? I am pipe dreaming?

 

[tRustyK5]

You know gearing is the issue, so why the Q about turbos and other stuff? I'd aim for 4.56's as it'd have your cruise rpm at 2000 rpm at 65 mph with those tires. At 55 mph it'd be turning 2400 rpm which is a nice rpm power wise in 4th. With another 12% gearing 4th and 55 mph on that hill with that trailer is definitely possible. Might even consider 4.56's and 33's when towing...

The suck with the NV4500 and SM 465 is the huge gap between gears. I recall the frustration of having more than enough power to pull our trailer up anything in third gear, but speed was low and R's high. I could pull the R's high enough to shift, then have it not have enough balls to hold 4th. To split that shift would have been great.

 

[Mikey von]

You know gearing is the issue, so why the Q about turbos and other stuff? I'd aim for 4.56's as it'd have your cruise rpm at 2000 rpm at 65 mph with those tires. At 55 mph it'd be turning 2400 rpm which is a nice rpm power wise in 4th. With another 12% gearing 4th and 55 mph on that hill with that trailer is definitely possible. Might even consider 4.56's and 33's when towing...

The suck with the NV4500 and SM 465 is the huge gap between gears. I recall the frustration of having more than enough power to pull our trailer up anything in third gear, but speed was low and R's high. I could pull the R's high enough to shift, then have it not have enough balls to hold 4th. To split that shift would have been great.

Because I push my turbo well out of it's efficiency map. I have wanted a bigger turbo before I even got it running.

Do you think gears will help that much? It will be my 1st upgrade. Not sure if I should look at 4.56 or 4.88. I will be going with a 14 bolt ff.

 

[miniwally]

Where are you taking your EGT? Pre turbo or post?

If pre isn't that like way low EGT? My Dmax runs 800 on a mild pull empty. I don't let my EGT's over 1300 for a sustained period. I've seen 1600 a few times just playing but was back to 1200 in a second. This of course is all pre-turbo with the pyro really close to the cylinder.

I would do gearing but I don't think your getting there without upping the power.

 

[Mikey von]

Where are you taking your EGT? Pre turbo or post?

If pre isn't that like way low EGT? My Dmax runs 800 on a mild pull empty. I don't let my EGT's over 1300 for a sustained period. I've seen 1600 a few times just playing but was back to 1200 in a second. This of course is all pre-turbo with the pyro really close to the cylinder.

I would do gearing but I don't think your getting there without upping the power.

EGT probe pre turbo, right underneath it at the collection point of the cross over. Standard banks kit location.

I have generally seen low EGT temps. On the same grade, without trailer, I have gotten my egts up to around 1150. That is lugging in 5th blowing smoke. Once I drop down to 4th, they would come back down to the 700-900 range.

 

[miniwally]

EGT probe pre turbo, right underneath it at the collection point of the cross over. Standard banks kit location.

I have generally seen low EGT temps. On the same grade, without trailer, I have gotten my egts up to around 1150. That is lugging in 5th blowing smoke. Once I drop down to 4th, they would come back down to the 700-900 range.

Sounds like you need more air to me. I'm also FAR from a 6.2 knowledgeable guy though.

For reference I pull 1200 degree egt doing even mild towing in my D-max.

 

[KirsL]

The egts you're seeing for a 6.2 are pretty good. The duramax is a completely different animal and does run little hotter egts but its built for those temps.

I have 4:56s with 35s on my truck and I've pulled my small enclosed trailer (7x12 with low roof height) and it pulls it pretty damn good. Now it doesn't have the same wind frontal area as your rv, so that does play into how it tows. Now if you think the trailer will end up much heavier when loaded then I would go with either smaller tires (33's) or 4:88s.

Now for more power for towing I've read a lot of guys having really good luck with the A-team turbo. You wont even need an intercooler with that turbo. Its a non-wastegated turbo so it is a little slower to spool and at low rpms there is almost no boost but once it has a load on it and from around 200 rpms and up its suppose to really shine. The biggest downfall to it is it cost like $800. But for a mostly bolt on upgrade that works its probably worth it.

 

[Mikey von]

My next turbo will be some variant of a holset 40. Most likely some type of hybrid (35 & 40 mixed).

 

[KirsL]

The HX40 is a good turbo and would work nice for towing. I'm going to be running one once I get the chance to install it.

 

[black dawg]

Do you know where the timing is set? Is fuel maxed? Those are low egts. The gm idi motors I have had, with the same turbo setup would get 1200 pretty easily. They tend to be smokey down low, because of the large turbine housing, but slightly retarding the timing makes the turbo more responsive.

On my ford Idi....using the same turbo, I added a big intercooler, the difference was huge.

 

[Mikey von]

Do you know where the timing is set? Is fuel maxed? Those are low egts. The gm idi motors I have had, with the same turbo setup would get 1200 pretty easily. They tend to be smokey down low, because of the large turbine housing, but slightly retarding the timing makes the turbo more responsive.

On my ford Idi....using the same turbo, I added a big intercooler, the difference was huge.

I do not know exactly where my timing is. A buddy and I set it by ear. I do not believe the pump is maxed. It is freshly rebuilt. I left it however the rebuilder set it.

 

[black dawg]

if the timing is close, the sound (volume level) of the rattle should stay the same from idle to wot under load.

 

[Hogback Fabrication]

Because I push my turbo well out of it's efficiency map. I have wanted a bigger turbo before I even got it running.

Do you think gears will help that much? It will be my 1st upgrade. Not sure if I should look at 4.56 or 4.88. I will be going with a 14 bolt ff.

A turbo past its map will run hot, you're probably not even close. And with little smoke, the turbo is probably pumping enough air to burn the fuel the injection pump can come up with. I don't think the turbo is the problem. A bigger turbo would probably make the engine work worse overall.

Honestly, I think you need more power.

Some guys alluded to you running something other than the TH400 in your signature, is that right?

Diesels that tow well need a LOT of help from forced induction. I honestly don't know, what kind of PSI will a 6.2/6.5 take reliably? How much fuel can they deliver to make how much hp?

 

[Mikey von]

A turbo past its map will run hot, you're probably not even close. And with little smoke, the turbo is probably pumping enough air to burn the fuel the injection pump can come up with. I don't think the turbo is the problem. A bigger turbo would probably make the engine work worse overall.

Honestly, I think you need more power.

Some guys alluded to you running something other than the TH400 in your signature, is that right?

Diesels that tow well need a LOT of help from forced induction. I honestly don't know, what kind of PSI will a 6.2/6.5 take reliably? How much fuel can they deliver to make how much hp?

You could be 100% right about my turbo being in range. I am a novice and just going by what others at the dieselplace.com are saying.

I do smoke good at times, like dropping to 4th on that grade. Or anytime I even slightly get on it after a shift. I wasn't smoking pulling the grade in 3rd pushing 11-15+ lbs of boost.

My sig is not up to date. I am running a nv4500.

My 6.2 is pretty well built. I would like a waste gated turbo pushing the low 20s.

I really don't know the answers, but definitely willing to try gears (which could also solve my parking brake issue) and a bigger turbo. At this point I have enough time, energy, money and some emotional attachment that I am going to give it a go.

 

[Hogback Fabrication]

With modified diesels, it's next to impossible to make them run completely clean without driver finesse. The new stuff with good tuners can do it, but otherwise, you have to understand that the "gas" pedal delivers fuel and that means smoke if the turbo isn't spooled yet or can't make enough air to burn it all.

Are you sure that your engine will take 20-25 lbs of boost?

 

[black dawg]

If your turbo is the same H-trim compressor that all of mine have been, I am sure it is well within its map even at 20 psi, BUT a wastegated (small exhaust side) would be nice.

Was that 4911 rebuilt (fuel settings) as stock? If so, smoke should be pretty minimal. If fuel is set as stock and it still pretty smokey, timing is probably too fast.

I have never dynoed these things, but over advanced timing doesnt seem to add any power....more smoke and noise, yes

What elevation are you dealing with?

 

[Mikey von]

To be honest, I don't remember what the fuel setting was set to. It was a fresh rebuild with new head (? I know most hard parts were replaced).

My home is at 3250'. Most driving done there and up to 6000, but I can be at 8000 or sea level in an hour.

 

[Mikey von]

With modified diesels, it's next to impossible to make them run completely clean without driver finesse. The new stuff with good tuners can do it, but otherwise, you have to understand that the "gas" pedal delivers fuel and that means smoke if the turbo isn't spooled yet or can't make enough air to burn it all.

Are you sure that your engine will take 20-25 lbs of boost?

I understand that there will be smoke, but I don't need to be leaving a 1/3 mile smoke screen when going from the 35 mph to 40 mph zone. It does clear quickly when on it because it builds boost.

My 6.2l is built. If it can't take 20 - 25 lbs, it will die trying!

 

[KirsL]

Remembering the thread in which that engine was built, it should certainly handle 20lbs of boost.

Which turbo are you currently running? If its one of the GM series of turbos 15 psi is about its max range. It can push much higher but it starts to push way too much heat which is a very bad thing. About the level of smoke a slight haze is preferable (least to me it is) for a non-emissions diesel. Now once you have a better turbo you can turn up the fuel screw to match it.

Timing by ear usually gets you pretty close. The timing on my engine is set with the line on the pump the width of it towards the drivers side. It does have a pretty decent rattle to it but I have the fuel turned up 1/2 a turn and its a .033 plunger DB2. So it can fuel pretty hard.

 

[Hogback Fabrication]

My 6.2l is built. If it can't take 20 - 25 lbs, it will die trying!

Just out of curiosity (never had a 6.2/6.5 diesel), what does built mean? I didn't know there were a lot of internal upgrades for them.