"Best" Injection Timing

[PwrSmoke]

I have an '86 6.9L that's had a 1st Generation Banks kit (non wastegated) on it since 1987. It's just about at 140K miles of trouble-free service and I've owned it since '87. It has a 3-inch downpipe with a 4-inch exhaust system (Dynomax) grafted on. It will make about 13 psi on hard acceleration at near sea level. Fuel setting is moderate, moderate smoke, running about 550-600 EGT at high cruise. It's a bit knocky at whatever the timing is at now, vs what it was before the pump rebuild. It runs well and will make 180-190 hp on the dyno (depending on the dyno).

When I had the pump rebuilt in '98, I borrowed a Rotunda timing tool and I THINK I set it to the same spec as the factory IDI turbo (8 BTDC), but don't recall. I bought a nice 78-0100 recently so I'd like to check it again. My questions:

1) Given the change to ULSD and all, is there a consensus for a good timing spec for a turbo IDI? I figure there are conditions to a number (i.e. all out power vs low smoke, etc), so if you have a recommendation, would you qualify it, please?

2) As a general question, would you set a wastegated vs non-wastegated engine differently.

Many thanks gents. Been subscribed for a long while but haven't even lurked lately (new F-150 project) and I forgot what a great IDI source this place was.

 

[redneckaggie]

http://www.oilburners.net/forums/showthread.php?t=23972&highlight=ULSD+timing

 

[PwrSmoke]

Thanks... that was a lot of what I was looking for.

Leads to another question about translating the BTDC readings offered by the Ferret to the ATDC reading from the Rotunda 28-0100.

 

[redneckaggie]

that i cant answer but there are some folks round here that know the equivalencies.

 

[PwrSmoke]

The Ferret instructions quote a difference of 7-10 degrees advanced. For those who have used both, does this appear to be accurate?

 

[77f250diesel]

Actually I don't think anyone here has compared both methods.

If your using the pulse [ferret] method...8.5-9 deg. BTDC @ 2000 RPM.

For lumy method go here.........
http://rides.webshots.com/album/34036876WgXWdI?start=12
click on 2 timing articles.

Hope that answers your question and wasn't your truck dynoed in an article or online ?


Dennis

 

[PwrSmoke]

Thanks. Yes, the truck was in a couple of magazines and will soon be seen in Diesel World.

 

[david85]

Look forward to the new feature, Jim.

After I replied on FTE,I was thinking to suggest you check out OBN since more of these guys have timing tools for their trucks, but it looks like some one else was good enough to point you in the right direction.

 

[RLDSL]

Thanks... that was a lot of what I was looking for.

Leads to another question about translating the BTDC readings offered by the Ferret to the ATDC reading from the Rotunda 28-0100.

It's actually simple to translate that to the ATDC readings of the lumy method, as the difference equates to 1.2 deg more advance in crankshaft rotation ( i.e. 9.7 = 8.5 pulse spec + 1.2 deg crankshaft rotation ), so just add 1.2 to the central lumy spec and you'll be all set

 

[Diesel JD]

So.... the lumy spec for 47 and up cetane was 1.5* ATDC at 1400 RPM, to advance the timing 1.2* you'd want 0.3*ATDC not 2.7* right? Or do I misunderstand??

 

[PwrSmoke]

It's actually simple to translate that to the ATDC readings of the lumy method, as the difference equates to 1.2 deg more advance in crankshaft rotation ( i.e. 9.7 = 8.5 pulse spec + 1.2 deg crankshaft rotation ), so just add 1.2 to the central lumy spec and you'll be all set

Yeah, thanks, I also got that from some of my research. Wish I know what the fuel cetane is soI could tune to the fuel. Can't use specific gravity as a test any more but I have been looking around and find some industry tests that show ULSD is averaging 47-49 cetane (even though they still say "minimum cetane" is still 40). I'm trying to get the number out of my local Shell distributor (from whom I buy my farm fuel and who services the local fuel station I mostly buy from for my street legal stuff). The local Shell diesel is what I run in the truck 90 percent of the time, so I will tune for that if I can get the number.

BTW, there will eventually be three Ford IDI stories in Diesel World. I try to "Fly the Flag" as much as I can!

 

[RLDSL]

So.... the lumy spec for 47 and up cetane was 1.5* ATDC at 1400 RPM, to advance the timing 1.2* you'd want 0.3*ATDC not 2.7* right? Or do I misunderstand??

Correct, As you are adding to the advance, I guess it should read 1.5 + neg 1.2 =0.3 since degrees btdc are essentially negative numbers Or to make it easier, just subtract the 1.2 for the lumy