Dialing in IP timing for turbo with charge air cooling

Hey guys, mods are in my signature, the thing that recently changed is I went back to a Ford lift pump which gives consistent 5 PSI at all throttle positions(unlike the Facet I ran for a few years, screwed the timing all up).

This one change has gained a lot of low end power, less smoke, and better MPGs.

So while I'm excited about that, I found my timing to be at almost 10* BTDC using my Ferret timing meter, with a fresh 9v battery.
Turns out it's really hard to move it just 2*!! At least with this pump, I'm telling you I moved it HALF a millimeter and I was at 7.5*. That took me 3 tries. Anywho I ran at 7.5*for a trip to work and everything was worse. Low end, boost, egts. I advanced it past 10* for the return trip but didn't have my meter at the time and it ran worse again.

Basically my timing seems to be best at 9.5*-10*. Which goes against most everything I've read for turbo engines over on FTE and much here as well. At least until recently when @Thewespaul has mentioned a few times that advanced timing lowers smoke and EGTs.

My IP was properly rebuilt by @typ4 a couple years ago and I also got pop-matched Stanadyne NOS injectors from him around that time also. I recently pop-tested them and they were within 50psi still. (Thanks Russ!)

I'm wondering if the charge air cooler has to do with running well with advanced timing?

Any input appreciated!
Thanks,
Joshua

I personally believe in timing by ear. You can play with numbers all you want, but when you get right down to it, if the "right" number produces a worse result... it's not right!

The best way to get it dialed in, IMHO, is by first getting the high end where you want it - adjust it back and forth until you get the best power at 2500+ RPM. Watch your exhaust - if you see blue/gray smoke, it needs to be more advanced. Black is either too advanced or overfueled.

Once you've got the high end dialed in, rotate the light-load advance cam as needed until you get the idle/low-end where you want it.

Both of these adjustments vary with IP, fuel, injectors, engine air temps/pressures etc, so it's hard to find a solid 'number'. It may be close to the numbers people use, but a couple degrees makes a huge difference.

Running well at 9.5* isn’t out of the ordinary for an idi, I wouldn’t recommend using the light load advance cam to adjust timing, it’s not going to be a linear adjustment like rotating the pump will be, if you’re going to adjust the timing without rotating the pump just pull the light load advance arm off and screw the set screw out for more advance and in for less advance.

The only other thing that I can add to what Macrobb said is that it doesn't matter who built your fuel system (as long as they're one of the few quality builders), what parts they used, how they did it, or anything else. They all have their own "personalities" and will run differently (maybe slightly, maybe greatly) from other systems that are "exactly the same" as yours. You will have to mess around with yours to find out what works best for it. Maybe 10* is your magic number wheere it runs the best.

Hmmm. Well I guess like so many other things it comes down to tuning and tweaking.

As for WOT power that doesn't seem to be changing much, it's a lot more about the low end for me as far as "feeling" the differences in timing. I pretty much always get 12-13psi by 2500-2600rpm unloaded and max out at 14 loaded with my trailer. (My unhooked wastegate starts to blow open around 12-13 psi I'm guessing)

So the easiest way for me to tell if I'm at a good timing is going up a steep hill by my house in 4th gear at about 1100rpms. If I can accelerate out of that low end and get the turbo to spool up I'll get 3psi by 1500rpm, that seems to be the best I can do. And the black smoke is MUCH more manageable now with the constant inlet pressure, so that's getting easier to use as a tuning guide also.

A lot of my concern with proper timing is MPGs. With my Facet I couldn't get over 12.5: empty, commuting to work. EVEN AFTER GOING TO 3.55 GEARS! But already I'm up over that on this last tank with only changing the lift pump. So that's encouraging. I also drive fast(not like a jerk, just fast)and it's a big heavy pickup so I'm not looking for 20mpgs, but I'm hoping for 15-16 at least.

Any other "butt dyno" tips I am missing?

@Macrobb if you can time by ear within 2-3* God bless you brother.
I went from 10* to 6.5* and I remember thinking "Wow, I cannot tell the difference between 10 and 6". Now that was a fully hot engine, using the cold start method would get me a lot closer but dang, sounded really similar to me!

The_Josh_Bear said:

@Macrobb if you can time by ear within 2-3* God bless you brother.
I went from 10* to 6.5* and I remember thinking "Wow, I cannot tell the difference between 10 and 6". Now that was a fully hot engine, using the cold start method would get me a lot closer but dang, sounded really similar to me!

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Unloaded, you won't really notice much I think. I notice it in the color of smoke, and at light throttle with a bit of a load, the "diesel rattle" that can go away when you floor it at the same RPM. Also, watch EGTs, with a constant setup(same hill/load etc).

At idle... it's basically way advanced anyway(to reduce smoke), so you won't notice much unless you are horribly retarded or advanced.

The factory timing spec is 8.5* BTDC + or - 2*. That is pretty liberal, giving a range of 6.5 to 10.5*! I think 8.5* is a good starting point.

There are a lot of variables, all of which can affect optimal timing:
Altitude (air pressure)
Ambient Air temperature
Load
Turbo or N/A
Fuel type
Condition of engine

By monitoring things like mpg, EGTs, butt dyno, and sound, you can fine tune these engines to what works for you.

Once, I replaced an injection pump in my 1992 2WD truck. It was kind of doggy, so I advanced the timing a bit. It really woke the engine up. After checking the timing, it was @ 11* BTDC! I backed it off a bit just to be safe.

On my 1986, I run a WMO cocktail, and this requires more advanced timing. I currently have it set at 9.5* BTDC and it makes lots of power and runs cool, but when I switch to the tank that has #2 diesel, it rattles like a ****. So, 9.5* is kind of a compromise. The 6.9 in this truck is also has a turbo.

Generally, I find turbocharged and engines that are heavily loaded prefer less advance.

That's my 6.9¢ worth.

bbjordan said:

On my 1986, I run a WMO cocktail, and this requires more advanced timing. I currently have it set at 9.5* BTDC and it makes lots of power and runs cool, but when I switch to the tank that has #2 diesel, it rattles like a ****. So, 9.5* is kind of a compromise. The 6.9 in this truck is also has a turbo.

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Your WMO cocktail, are you adding RUG to the mix or just 50-50 diesel WMO? If it's the former, maby add a little more gasoline to the mix, which will burn faster, thereby increasing the cetane number of your fuel.

bbjordan said:

Generally, I find turbocharged and engines that are heavily loaded prefer less advance.

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Yup, I totally agree. I assume because you end up with a hotter cylinder(higher temperature air in intake, then compressed = really high pre-combustion temps), so the fuel atomizes and burns faster.[/QUOTE]

Macrobb, my WMO cocktail is 85% WMO, 10% RUG and 5% BioDiesel.

I have been hesitant about adding more RUG for a couple of reasons:
1. Cost. (Ya, I know that's pretty lame given the small incremental cost. )
2. The current mix works so well. More power and great fuel mileage.

Also the '86 is parked for now while a mess around with the first truck in my sig. I run a different WMO mix in the 7.3 PSD: 45% WMO, 45% #2 Diesel and 10% biodiesel. It works great, especially under load. If I run it cool, or lightly loaded it tends to coke the injectors. A good heavily loaded run with a mix of about 4L (1 US gal.) in the rear tank of #2 diesel fixes that.

I think WMO cocktail in the PSD would work better with a little more advance, but I can't manually change the timing on the PSD.

BTW, I run both trucks without an engine fan!

I suspect you are right about the higher cylinder temps.

Joshua, sorry for the hijack.

When playing with your timing, keep record of your boost/egt/timing and density altitude. Density altitude changes can really skew your other readings.

I dont quote timing specs or boost predictions because as I've said countless times, every setup is different.
I have never had a meter on my truck, but I have timed enough yeeeears ago that I had, notice I say HAD, a good ear for them.
I am going to check it before and after the new injector install and play with it some.
The engine will tell you when its happy.

Thewespaul said:

When playing with your timing, keep record of your boost/egt/timing and density altitude. Density altitude changes can really skew your other readings.

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How do I measure density altitude?

The_Josh_Bear said:

How do I measure density altitude?

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If you have an iPhone you can use the app AUTODENS to measure density altitude. I’m sure android has a similar app available. You can also google your zip and it will tell you.

Interesting update:
I advanced it back to around 10.5* where it seemed to do best for now.
Then:
I did a Kreen cleanse in both oil and fuel, nothing crazy just the normal dosage.
Idle almost immediately smoothed out and engine seemed great in the driveway.

But getting out on the road I had lower power and less boost with essentially all other things being equal. Some black smoke at WOT until 2500rpms.
So I drove that tank through then with fresh fuel it was even worse with more smoke. Ended up at 13mpgs(which is great compared to my Facet pump mileage, 13.5 was about wonderful then), and yet the whole trip was with my cabover camper with total weight of 9700#!! And of course it has the aerodynamics of a barn.

So then I dropped the timing to 9.5ish where it sits now and boost is better, everything is better. I think I'll drop the timing again and see how she likes 8.5 after the cleaning.

I was under the impression that our 5% Bio-D was an excellent lubricity additive, but apparently we need to run cleaner as well??
Thoughts? The change in performance was rather stark to me, I'm surprised that just some cleaner would affect timing this much.

Thewespaul said:

If you have an iPhone you can use the app AUTODENS to measure density altitude. I’m sure android has a similar app available. You can also google your zip and it will tell you.

Click to expand...

iPhone?? No need for that kind of language around here Wes! Lol

J/K but sounds like this is something that stays the same in the same location or is it like barometric pressure that changes?