Tuning for 90hp injectors ?

[icem237]

What is the rule/s of thumb when it comes to tuning for larger injectors? Less duration? Lower timing? I had to have all of my injectors replaced and went ahead with I.I. 90hp models.

Now i know with stock fueling and turbo i cant make full use of these but still would like some pointers if anyone would be so kind?

Thanks in advance! :thumb_yello:

[DoghouseDiesel]

Your biggest adjustments are going to be in the duration, but it will be mostly in the lower end of the table to control the smoke in daily driving.

Once you put them in, just do some data logging and see where you normal day to day driving habits put you on the duration map. The best thing to do is use the runway highlighting feature and have the map open while the ScanTool is doing the data logging. This will let you see the areas you'll be adjusting...trust me, it makes it a lot easier.

90hp injectors are approx 40 - 45% over. This doesn't mean you'll be cutting duration by that %, but start with 10% at a time until the smoke tapers off under normal driving and acceleration. Once it gets to a haze, then adjust your timing values a bit.

You can also lower the rail pressure slightly in those same areas. Same pressure going through larger holes = more fuel delivered. 90's aren't so big that a slight decrease in pressure will bother anything. With my 160's, I have the rail pressure lowered slightly in the daily driving range, so I can extend the duration slightly. This seems to help quiet the motor too with less of an abrupt cylinder pressure rise.

There are a few ways you can do it, but ultimately you bought 90's for more power on top. Leave your upper RPM settings as they are and you'll be fine. Just dial back your daily driving settings to get rid of the smoke.

[AdamRRT]

That's good info man. Thanks for this thread.

[icem237]

Your biggest adjustments are going to be in the duration, but it will be mostly in the lower end of the table to control the smoke in daily driving.

Once you put them in, just do some data logging and see where you normal day to day driving habits put you on the duration map. The best thing to do is use the runway highlighting feature and have the map open while the ScanTool is doing the data logging. This will let you see the areas you'll be adjusting...trust me, it makes it a lot easier.

90hp injectors are approx 40 - 45% over. This doesn't mean you'll be cutting duration by that %, but start with 10% at a time until the smoke tapers off under normal driving and acceleration. Once it gets to a haze, then adjust your timing values a bit.

You can also lower the rail pressure slightly in those same areas. Same pressure going through larger holes = more fuel delivered. 90's aren't so big that a slight decrease in pressure will bother anything. With my 160's, I have the rail pressure lowered slightly in the daily driving range, so I can extend the duration slightly. This seems to help quiet the motor too with less of an abrupt cylinder pressure rise.

There are a few ways you can do it, but ultimately you bought 90's for more power on top. Leave your upper RPM settings as they are and you'll be fine. Just dial back your daily driving settings to get rid of the smoke.

Really appreciate the help!!! Makes perfect sense.... I thought it would be more complicated than that but again I was wrong lol.... :mrgreen:

[DoghouseDiesel]

It's not necesarrilly complicated, it's just time consuming dialing out the smoke.

Adjusting duration for smoke control is what takes me the longest. I try to use the duration tables to control it vs the limiters.

Timing.....no big deal.

Rail pressure....no big deal.

Duration is what takes the most time to adjust when you've increased injector size and need smoke control in a daily driver.

For example, in my truck, most of my daily driving is in the 30 - 70mm3 range and up to 110MPa on the rail pressure, that's where I focus on for smoke control. 70mm3 - 110mm3 is mostly passing / harder acceleration and anything above that I consider WOT anyways.

[icem237]

It's not necesarrilly complicated, it's just time consuming dialing out the smoke.

Adjusting duration for smoke control is what takes me the longest. I try to use the duration tables to control it vs the limiters.

Timing.....no big deal.

Rail pressure....no big deal.

Duration is what takes the most time to adjust when you've increased injector size and need smoke control in a daily driver.

For example, in my truck, most of my daily driving is in the 30 - 70mm3 range and up to 110MPa on the rail pressure, that's where I focus on for smoke control. 70mm3 - 110mm3 is mostly passing / harder acceleration and anything above that I consider WOT anyways.

Perfect info. Exactly what i was looking for. I mainly went the 90hp tip route because it gave me some room to grow without getting too wild. I like components i can build on, makes me feel like i get more for my money without having to spend a ton at one time.

I have a cam and E.D. 63/68/14 to put on thats just been laying around and now i have the injector to really make it work i think. Efi should really make it sing when i get the fuel system built up some.

[DoghouseDiesel]

You've got plenty of fuel right now.

A stock CP3 will support 90's up into the low to mid 600 hp range without issue.

The intank lift pump does an "okay" job of keeping at that point also.

Git after it.

[mstordahl]

Just to clarify, reducing the timing is what will help to reduce the low rpm smoke, correct? Thanks.

[FUBAR]

A stock CP3 will support 90's up into the low to mid 600 hp range without issue.

The intank lift pump does an "okay" job of keeping at that point also.


I'm in the same exact boat as Icem. The only difference being is I'm installing a mechanical lift pump that idles at 8-10 psi and relieved at 17psi WOT. I have enlarged the inlet/outlet on the gear rotor pump on back of the CP3, but that is all. Still on stock turbo right now too. I wonder if the mech lift pump will help keep the rail pressure up at all vs an electric or stock one??

Thanks,
Andrew

[DoghouseDiesel]

Just to clarify, reducing the timing is what will help to reduce the low rpm smoke, correct? Thanks.

A little over simplified, but yes.

[mstordahl]

Thanks Rich, I was refering to timing and not all the other variables.

[DoghouseDiesel]

Reducing the timing will shift the main event later in the cycle and will retain more heat energy to spool the turbo.

The quicker it's lit, the quicker that smoke is gone and the more responsive the engine is.

It's a double edged sword though. Timing is power. The more you can advance the timing, the more power the engine generates, but the EGT's will be cooler and the less boost the turbo produces.

Retard the timing too much and the motor is sluggish. -2 to 5 degrees seems to do well on most trucks in those lower RPM's.

The other thing you notice with these low timing numbers is almost no rattle, especially if the timing is AFTER TDC. 0 to -2 degrees at idle through 1000 RPM and there nearly no rattle.

[mstordahl]

Great info Rich, that is exactly how I understood it as well, thanks for clarifying. Like most things, its give and take, nothing is free.

Thanks again, this kind of info really helps others along and makes the product look better. Any person can use a tool, but it takes some know how to use it to its best.

[AH64ID]

For example, in my truck, most of my daily driving is in the 30 - 70mm3 range and up to 110MPa on the rail pressure, that's where I focus on for smoke control. 70mm3 - 110mm3 is mostly passing / harder acceleration and anything above that I consider WOT anyways.

Since I am sure you are running a lot more fuel than that in reality, you just leave the OE mm3 range in and increase the duration and the ECM thinks your only injecting that amount?

[DoghouseDiesel]

Remember, the mm3's in the case are not a real value, it's just a reference.

Change anything in duration or pressure and you wouldn't have an accurate cubic millimeter value if that was the case.

My mm3 values are modified, as are my rail pressure values, so they allow me to be more accurate in the daily driving ranges and less so in the WOT and idle ranges. For example, from 40 - 60 mm3 I advance the scale by 2 versus from 100 to 145 I advance the scale by 15.

[AH64ID]

So you have modified your timing/duration and mm3 reference tables?

Max OE mm3 is 140 correct?

[DoghouseDiesel]

Correct.

[icem237]

Rich when trying to build bottom end power, i raise duraion up till i hit a point where it will feel really strong , still clean , but it will idle rough just a bit at idle. I dont change anything in the idle range. timing doesnt change the rough transistion from idle to acceleration. So i try to lower the duration back down and that will work but the point where the rough feeling moves further out up the rpm range. I cant seem to put 2 and 2 together as to what im doing wrong. I know this might not make total sense but i think its just a basic error that right in front of me but lol im just not getting it.

[DoghouseDiesel]

Down low, don't worry too much about the duration....get the pressure to ramp in faster. This will smooth that out a bit.

Save the duration for higher in the RPM range.

What you're going to find is that in the lower RPM range, you're going to be lowering the duration values. You're going the wrong way by raising them up. The only reason to raise them is to fool the engine into thinking you have larger injectors than you really do.....sort of. You'll get better results if you ramp in the rail pressure a little faster here vs trying to bring in duration.

[icem237]

Down low, don't worry too much about the duration....get the pressure to ramp in faster. This will smooth that out a bit.

Save the duration for higher in the RPM range.

What you're going to find is that in the lower RPM range, you're going to be lowering the duration values. You're going the wrong way by raising them up. The only reason to raise them is to fool the engine into thinking you have larger injectors than you really do.....sort of. You'll get better results if you ramp in the rail pressure a little faster here vs trying to bring in duration.

Makes perfect sense! I knew it was simpler than what i making it , in my head anyway. Thanks!

[DoghouseDiesel]

Once you bring in that rail pressure a little faster, you should notice it smooth out a bit and your smoke should taper off.

I'm not talking a huge ramp here either. I'm talking 2 - 4k psi between 1000 - 2000 RPM.

Your idle RPM rail pressure should be around 6800 - 7200, don't mess with that. Once you put it in gear it should come up to around 8500 - 9000.

[icem237]

The reason i want more bottom end is i feel like it lacks there a little when towing. I would like to get it moving a bit better starting out with my manual.

[DoghouseDiesel]

Am I missing something or is your truck running a stock turbo?

[icem237]

It does right now , but i have a 63/68 from ED to put on. been delaying till the injectors were replaced.

And cam for that matter.

[DoghouseDiesel]

Okay, so you're running stock sticks in it right now?

[icem237]

No I have the 90's installed yesterday. been driving it around on the stock tune .

[DoghouseDiesel]

Okay, with 90's and a stock turbo, you're really not going to be able to control that smoke without severely limiting the duration. The stock turbo just won't clear those up.

I'd cut the duration in 30 - 70 mm3 range so that you don't see over 1800 uS until you're up in the 80 - 90 mm3 range until 1800 RPM's or so. Also, keep it it so you're under 800 uS in the 30 - 55 mm3 range until you're over 1400 RPM's.

Don't wait for the cam to put that turbo on. You'll have no problem lighting that turbo with a stock cam. It'll just be better with a decent cam.

What have you don't with all your limiting tables?

[icem237]

not a thing yet as i wasnt sure where to go with this, till you helped me i was bit clueless.

[DoghouseDiesel]

Okay, those limiters are going to take care of a lot of the response down low, especially the torque limiter table.

Take a look at the limiting tables and see what "doesn't make sense". If it LOOKS like it would hold back power, it probably is.

[tinman]

What about the pilot? With the larger injectors, more fuel will be injected sooner, so I retarded my pilot timing by 2 degrees and pulled back the mm3 from 15-25% to compensate for my 50hp nozzles. Truck runs a lot smoother and a little quieter with these changes. I'm sure the mileage is better since less fuel is in the pilot event. I am wondering what the ideal timing and quantity of the pilot is when tuning without consideration of emissions (mileage, quietness, efficient combustion of the main event, etc).

[DoghouseDiesel]

You have to look at the TOTAL timing too. Don't just retard the timing because you have slightly larger injectors, 50's won't make any dramatic effect on the pilot event. Its such a small event as it is that all you have to do is cut the qty a small percentage, if at all, and you'd be fine.

What I mean with total timing is look at how much timing you have with your main event AND the pilot event before TDC. There are places where we've seen this as high as 88 - 89 degrees BTDC and that's just not needed.

What I've seen with most of mine is that as long as you keep a relatively small pilot and place it 12 - 15 degrees ahead of your main in the lower RPM's and lower load ranges, it keeps the noise and pressure spikes in check.

My pilot event, both timing and qty actually look 100% inverse of my main event. Under heavy throttle or high RPM, the engine is running on a single event to make use of the power because that point I'm not concerned with noise.