Best low rpm towing turbo

[Grinch]

Good evening, 

I am a new member and this is my first post, so bare with me please. 

I am running a 1994 2500 Cummins 4x4 with the NV 4500. It has a 3000 rpm governor spring, slightly larger delivery valves and 5x.013 injectors. 

I pull a heavy RV trailer and am looking for a low rpm, high boost turbo that will keep some control of my EGT'S. I had a 58/67/6 for a week that I absolutely loved, but it blew the front bearing out of it. Any suggestions of a comparable turbo out there would be VERY appreciated.  Thank you in advance!

[Mopar1973Man]

Typically the 24V guys typically aim for 62/68/12 turbo and run 150 HP injectors (7 x 0.010) as a good combo. Even a stock HX35W turbo is 54/60/12. Then what I'm running is HX35/40 hybrid turbo which is like the HE351 but larger exhaust housing (60/60/12) where typically the HE351 is a (60/60/9).

[Grinch]

Wouldn't a larger exhaust housing make it spool slower?

[Mopar1973Man]

Yes, but moves the power band up towards 1,500 to 2,000 rpm where it builds good boost, without EGT issues. Choke point on your 6cm2 turbo won't let you build boost to much before the drive pressure is over whelming the turbine.

[Grinch]

Interesting points. I like it. 

I usually run my truck 1200 to 2400 rpms.  What would you recommend for me. Remember that I have a 1994 12 valve.

[Mopar1973Man]

HX35W would work short on the top end. 

 

DAP for 62/68/12 would be the common for 150 HP setup. Then I would like to know how much timing you running?

[Me78569]

I'd be looking at the 57 sxe DAP has,  

 

 

or a 351 cw if you want to piece something together on the cheap

[Grinch]

I am running 16.5 degrees of timing. 

On 7/5/2020 at 10:30 AM, Mopar1973Man said:

HX35W would work short on the top end. 

 

DAP for 62/68/12 would be the common for 150 HP setup. Then I would like to know how much timing you running?

 

[dieselautopower]

this turbo is a bit small for 5x.013 but its great for 400HP.  Big upgrade form HX35/40 or K27

https://www.dieselautopower.com/s200gx-e-dodge-ram-upgrade-turbo-12769880001

 

5x.013 you will want the 62/68/12 SXE.  They wont tow as well as your stock turbo, but midrange and top end will be much better.

[Mopar1973Man]

On 7/6/2020 at 4:50 PM, Grinch said:

Then I would like to know how much timing you running?

 

There is different things that affect timing amounts.

• Pop pressure the injectors are built too. High pop pressure makes them late (need more advance).
• Final gear and tire size, Large tires like more retard.
• Manual or Automatic (manuals like a bit more retard to launch).
• Cetane of the fuel. High cetane needs more retard since the fuel lights easy. Low cetane could use more timing because of its slow ignition quality.

Best way I found is play with the timing on a flat quiet road. Then keep trying different values to the engine load goes down. Basically if oyu have a flat road and set the cruise for 65 MPH. if the current timing was 22% engine load and you advance timing a degree more and your next test at 65 MPH on your flat road nets you 20% engine load try advancing again if it goes down again keep going till the engine load rises. This rise will be negative torque in other words you firing so early that the piston is being forced down while traveling up yet. Then back off a few degrees and now you should be about right. 

 

Like my "economy tune" lands me right about 23* at 2,000 RPM at 66 MPH, 245's tires gives me a final ratio of 3.69:1. Being my tires are small and the final ratio is lower I can start up with more timing in the bottom end and do a spread of +4.5* between bands. 15, 19.5, 24, 28.5. Then have +4* for cruise timing. Even with my injectors at 320 bar this works out great. Engine oil temp float 160 to 170*F typically. EGT's are lower. MPG is up. This tune with high timing builds little boost till in the upper end. Not designed for racing...

 

Switch tunes to my performance tune. I dropped to 14, 18.5, 23.0, 27.5... This gives me a bit better edge getting launched in a hurry from light to light. Fuel table is a bit fatter across the mid to upper end. With a bit less timing I'm now building more boost get launched. 

Edited July 21, 2020 by Mopar1973Man