CM871 Engine cycle...

[Rawze]

(09-15-2017 )Squish099 Wrote:  Rawze, you know my tune better then anyone. On my 2250 how much power would be lost if it was set to a max of 30-32psi instead of the 34-35 (I've seen a high of 36 1 morning on Monteagle). Just curious. I would gladly give up some power for longer life, especially for the fuel pump.......

on the 2250, 34-36 max boost is correct. 30-32 would be a bit on the low side.

[Squish099]

How much power would be lost? And would it be any easier on the fuel pump?

[Rawze]

(09-16-2017 )Squish099 Wrote:  How much power would be lost? And would it be any easier on the fuel pump?

I cannot predict accurately the power loss, as it is on a curve based on oxygen levels. It would not be a lot though until you started seeing the EGT's climb by a hundred degrees or more. As the EGT's climb, the power is lost to heat and combustion inefficiency. it is a balancing act, where too much boost will cause an efficiency fall off, and too little will too.

As far as the fuel pump longevity goes, boost pressure would have little to no effect. The fuel pump is simply supplying the fuel rail with high pressures far greater than the combustion pressures. It is also controlled by a separate system than the turbocharger. A proper de-mandate though, should use overall less peak fuel pump pressures, lengthening its lifespan. This is because fuel penetration requirements are less to achieve the same peak pressures.

just some thoughts on it off the top of my head any ways.

[hepy]

(09-14-2017 )Rawze Wrote:  

(09-13-2017 )hepy Wrote:  

(12-23-2016 )Unilevers Wrote:  I personally run the TG method. both work but the MCF method is too reliant on feedback and i find is very lazy and slow no matter how you tune it. My favorite is when the PID screws up and the logic jumps outside it range and the vgt starts going to infinity....because this happens with MCF mapping.

I know where i want that turbo, and i want it where i tell it to be with no BS from it. Yes this requires tweaking and tuning for each and every truck, but over time you know ballpark numbers and can dial them in much faster than you would think. This is why i always ask on remotes what type of truck is it, because it matters alot.

What if somebody that has a 2009 kw t2000 isx400st that had a delete how many psi do you set the boast on and what other changes do you make

At 400 HP, you should be peaking about 34-35 psi or so boost pressure with the Vg. This is assuming you have the injection timing and all other things adjusted correctly for its operation too.

Thanks but when I bought the truck I didn't knew it had a delete until latter on so I don't know what all have been done to it but I did had to put a turbo on it and when I got the truck it didn't have the factory turbo on it and it now has over 800,000 miles could you explain to what all I need to do to have it running right thanks

[hepy]

Hay is that cm871 a isx400st if so are you saying the 30psi is a good set for that engine because mines is set 22 psi 23 somewhere around there and I want to take it up some

[Rawze]

(10-05-2017 )hepy Wrote:  Hay is that cm871 a isx400st if so are you saying the 30psi is a good set for that engine because mines is set 22 psi 23 somewhere around there and I want to take it up some

A CM871 should peak around 34-36 psi boost peak at 400 HP. 30 and below is TOO LOW and EGT's will be too high for the power you are making. It sounds like you have some bad programming and/or some things wrong with that engine.

I don't know about anyone else, but I can't afford to "take guesses" and "gamble" and piss around while my engine destroys itself because of uncertianty.---

KNOW WHAT YOU HAVE -- WITHOUT QUESTION -- YOUR BUSINESS AND INCOME AND POSSIBLY YOUR LIFE DEPEND ON IT!!!

And if your that unsure,.. take it to Gearhead, Mr. Hag, or Unilevers and HAVE IT FIXED RIGHT!!!

[hepy]

Where can I find one of those shops I'm from Mississippi I sure would appreciate if you could point me to where one is thanks

[Hammerhead]

If you're in MS, Mr. Hagg isn't too far away.
He's just south of Atlanta.

[hepy]

(10-24-2017 )Hammerhead Wrote:  If you're in MS, Mr. Hagg isn't too far away.
He's just south of Atlanta.

What's the name of the shop so when I'm in that area I'll swing by there