SOI Advice

[Marajin]

My take on boost and cold environments.,

You have someone who has set their truck to push boost to 39-40 psi when it is 70 degrees outside. They get into -30 degree weather, and the intake air is now very cold too because they didn't cover the front of their truck up to prevent this.

The air is a lot more dense, and this is the exact same effect as adding boost.

Now, 40 psi on the gauge is more like 42-43 psi. You start to get problems just like when you have too much boost. Not so good for engine.

The solution? --

You can make 700hp with 35-36 lbs of boost on 871 isx. I have seen this plenty of times. - Lower the overall boost levels for the engine all around. Bigger hp engines usually have bigger turbo, piping, and cac. They have more flow and do not need as much boost to make hp.

then when you get into cold weather and more dense air? -- you are still within spec.

->
by the way you are right in the same scenario if you have altered mcf tables to get boost to go up to 39-40.
->

You want the best of both?--- Lower boost a little bit and keep your foot out of it in the extreme cold and cover your radiator a bit so the air is not so cold going in. Having really cold air going into an engine that is working hard can have bad consequences all on its own. I have heard of pistons cracking in cars and truck both because of sudden inrush of extreme cold air when a high engine load was suddenly released by a clutch or tranny that let go all at once.

[Vin]

If I suspected I had lower than usual fuel economy or heard something sound amiss with the timing, first check or replace the IMAP Sensor, Exhaust Back-Pressure Sensor, and run a bottle of Power Service Diesel Kleen.

Mr Hagg has a pressure regulator and gauge that he calibrates Boost Gauges with, nothing worse than adjusting tuning based on bad feedback data from sensors or gauges.

[Rawze]

(01-26-2017 )Vin Wrote:  ...
Mr Hagg has a pressure regulator and gauge that he calibrates Boost Gauges with, nothing worse than adjusting tuning based on bad feedback data from sensors or gauges.
..

It is not very common but I have have seen a few gauges out of calibration right from the box.

[Running rough]

(01-26-2017 )Marajin Wrote:  

(01-25-2017 )Running rough Wrote:  ..
I am led to believe @m*m^2 style tuning uses a fixed position at a given rpm and load meaning you more then likely will have more boost the colder and denser the air is that is why the turbo mapping has to be fine tuned to the type of truck and environment it will run in, it is said that the stock mass flow calculation turbo mapping can not touch the @m*m^2 custom mapping in both performance and fuel efficiency when it is dialled in correctly for the given truck and application,
...

Actually I can see that it has an operating window with a min and max correction range to the turbo itself. It is not completely "fixed". It simply limits the engine from allowing it to go too far out of whatever bounds someone has set for it. - Need a bigger window? -- just make the window larger.

I tend to mostly agree with this advice

http://rawze.com/forums/showthread.php?t...2#pid11192

that you should be on the lower side of optimized boost levels for exactly those reasons. I would think that setting a bit on the lower side also gives it that wiggle room that may have been programmed out of your own engine(s) to get more out of them.

(01-25-2017 )Running rough Wrote:  ...
soi is another thing but I would think the cold air up here combined with extremely advanced timing i would have a bad feeling about it under heavy load, for instance I can notice slight crank flex vibrations, in cold weather with the high torque cals, and I believe the timing is mostly stock, take it in to warmer summer conditions and the crank flex disappears, now if a guy advance the timing to much I am sure the vibrations would increase, and that can't be good, but as always don't lug the snot out of your engines if you want maximum life,

As far as hot/cold environ, high altitude, sea level, etc.. The "explained" doc I read on MM strongly and heavily is against disabling corrections for altitude, temp and everything else an engine needs to make proper timing, etc.

I have also seen plenty of factory programs with MCF turned on that could not handle extreme cold or hot too. I think even Unilevers talked about it on here before because he has to deal with it up north where he is at quite a lot.


Just what I see here after reading all of this ..

- Not very many people have power set for high torque or go to the extremes that you seem to want to do. Looks counter-productive to push an engine hard like that only to have to spend so much money replacing its guts more often for such slight gains on the roadways. - Throw that upper edge programming and mods and pushing boost to its upper end into an extreme cold or hot and that may be the very thing that does your engine in. I think at that point you would only have yourself to blame for it. Those things can only take so much stress before they say enough is enough. Just because you keep wanting more does not mean it can keep up long term, or in extreme hot/cold. There must be wiggle room for just those scenarios. I know plenty of guys that have pushed and pushed and pushed,.. only to end up with a broken engine saying that it costs too much to operate like that. They usually always end up setting their truck power back down to more reasonable levels and settings in the end.

You seem to get the impression that I am running my engine all out or lugging the snot out of it, I can tell you I drive it like there is an eggshell under my foot

[Marajin]

(01-26-2017 )Running rough Wrote:  You seem to get the impression that I am running my engine all out or lugging the snot out of it, I can tell you I drive it like there is an eggshell under my foot

Not trying to disrespect anyone here. A lot of your posts seem to point in this direction is all. I am glad you have respect for what you have done and do not abuse it.

I know plenty of truck owners who do not though. They do nothing but push the pedal all the way to the floor everywhere they go and hold it against a governor all day every day and let it lug the crap out of everything as it slows down then wonder why their engine has such a short lifespan or ends up with liner issues. All they seem to want is more power to make up for not being able to go faster and they all end up with popped engine when they put them up at 2050+ torque and put it on the floor every chance they get.

[gearhead]

The best advice i can give on tuning soi is every truck is different based on power loads and driving style. I have stopped using soi increment do it in the table much better results will come from it.

[Nilao]

Unfortunately I only have revision Q. I'd like to do it in the tables but I don't have all the fancy gadgetry to calculate it.

[yamajason]

(01-29-2017 )Nilao Wrote:  Unfortunately I only have revision Q. I'd like to do it in the tables but I don't have all the fancy gadgetry to calculate it.

Just have your tuner update it for you, probably for free. I had version Q that I did myself, no more check engine codes....yay! I read the document several times...chatted with tuners...and I consider myself a smart guy but the results of getting it custom tuned by a guy that does it professionally showed I didnt know Jack shi#t more than running an overlay and copy paste. I know I can run an overhead as good as rawze but when it comes to tuning...

[Brock]

(01-29-2017 )gearhead Wrote:  The best advice i can give on tuning soi is every truck is different based on power loads and driving style. I have stopped using soi increment do it in the table much better results will come from it.

It's great to see the evolution. It wasn't too long ago that touching the tables was shunned upon.... still would be if a idiot like me was doing it!