4bt Compound Turbo Setup

[Mountain Life Overlanding]

New to this site; referred to this site, spoken to as a very knowledgeable group on Cummins and turbos. 
 

Short as I can speak to this, 4bt swap into a ram 2500 chassis with 56 Willys Wagon as body. NV5600 6spd manual. 4.10 gears. And my first time to have a set of compound turbos!
 

Looking for some help/further education on tuning compound turbos.

 

Setup is 

Holset 44mm HX30W 

Holset HE351W 12cm²

P7100 pump

Hamilton cam

Stock injectors

 

I currently just placed a boost gauge sensor in plate just to the rear of neck. 
And I have and EGT gauge in pipe between turbos. 
 

My request, info on how to properly tune these turbos?

 

I hear …

Total Boost Pressure

Exhaust Boost Pressure

Exhaust Drive Pressure 

Monitoring EGT’s(what is idle EGT, highway EGT, what is too high EGT)

 

I really could use some good advice. 

Edited July 10, 2023 by Mountain Life Overlanding

[Mopar1973Man]

So... just an tidbit of info. I'm running 7 x 0.010 injector (+150 HP) that are popped at 320 bar which is +10 over stock. I'm still running a stock HX35W turbo all on the ISB. EGTs are low. Your asking how...

 

The biggest factor is proper timing but since P-pump has no dynamic timing this is limiting you. I'm currently run about 24.5 degrees BTDC at 2k RPM at cruise about 2 to 3 PSI of boost, 550 EGTs. But under heavy throttle dropping to 17 degrees BTDC at 2k RPM now building boost never even getting to 1,200 EGTs.

 

When you advance timing your burning more fuel in the cylinder and EGTs will drop. When you retard your using some of that burning fuel to spool the turbo and EGTs will rise.

 

So in your setup up you'll need to work with your timing to get a balance giving enough to launch and spool enough to control smoke and build boost, then advanced enough so EGTs are under control. I would suggest advancing slightly. Wouldn't hurt to look at different fuel plate profiles that fuel more so in the higher boost range.

 

Other problem is stock injectors will not have enough fuel to spool twins properly.  I've shown I can control EGTs with +150 HP injectors on a stock HX35W turbo and hold low EGTs. 

 

https://www.tiktok.com/t/ZT8dfYGYK/

 

Older tune but still low EGTs.

https://www.tiktok.com/t/ZT8dfSdHb/

Edited July 10, 2023 by Mopar1973Man