I've added an SAFC and 720cc injectors(secondaries only) to my 88TII and I'm wondering at what point would I need to start thinking about advancing ignition. I guess another way to put it would be, how far can I go with fuel mods and intercooling(fmic, water injection) mods before it's necessary to advance ignition(I would assume by adding a full blown programmable ecu like a Haltech).

 

Normally you want to retard ignition for more boost and what not.

 

Thanks for the correction. I guess I'm showing my 'exhaust leak' status.
So when do I need to worry about screwing around with ignition timing--I think this is a more accurate question.

 

Stock efi runs a more than safe ignition timing. Most standalone guys run twice what the stock efi runs

 

By twice, you mean twice the boost?

 

Don't mess around with advancing the ignition timing on a stock ECU.
You'll run into more dangers than it's worth.

With a stand-alone EMS, it's a difference story.

In general, ignition timing advance does not increase power as drastically as with piston engines.  Those 1 to 5hp increase is not worth the 5 to 10 degrees of increased ignition timing that can kill your engine, especially on a turbo one.


-Ted

 

So, for example, if I'm running 20 lbs of boost with fuel mods that support it, I don't need to screw around with ignition timing? The reason I ask is not to up the hp, but to prevent detonation. I was under the impression that at some point of upping boost, you need to increase ignition timing.

 

You got it backwards.

More Boost means RETARD (less) Ignition

 

What is it about the stock ECU that disallows advancing the timing that a stand-alone allows?

Example: Can I advance my timing only 1 or 2 degrees on my N/A without worries?

 

You cannot run 20psi on the stock ECU.
Let me rephrase that...I would NOT recommend running 20psi on the stock ECU.


-Ted

 

Advancing the ignition timing on a stock ECU will usually mean "moving the CAS".  If you move the CAS, this means ALL ignition timing will be moved this amount.

The stand-alone EMS allows you to change ignition timing where you want / need it and not where you don't.  In general you can run up to 10-degrees more timing in very low boost ranges (at "0" up to 2-4psi of boost), but when you start to shoot for 10psi or more, the stock ECU ignition timing of about 18BTDC is more than adequate for pump gas.

For NA, you can get away with running slightly more advanced ignition timing via the CAS.  Start with 3-degrees more and see if it likes it.  Run it up to 5-degrees to see if you don't run into detonation problems.  BE AWARE YOU'RE TAKING A RISK OF ENGINE DAMAGE IF YOU TRY THIS.  This will almost require you to run "premium" octane in your NA.


-Ted

 

so on n/a it would be safe to run 3-degrees if i always use 91 octane ?

 

Yes, 3-degrees is safe.


-Ted

 

What is the highest amount of boost that you would recommend running on a stock ECU(considering that the hybrid turbo can handle it) and why-what would happen if you ran higher than your highest recommended amount of boost on a stock ECU?

 

You also need to keep in mind that the CFM from the stock turbo is a different flow then what a hybrid turbo is putting out. so 5psi @ stock turbo (say 180hp to the wheels) can be quite different then 5psi @ your new turbo. (could be 220 at the wheels.. you never know..)

So you should post some more info to be sure what a safe number would be running for your hybrid...

This is all info ive read from searches or other people posting so something may be wrong... please correct me if so.

 

how do you advance the timing?

 

Keep this in mind...the stock boost sensor is a "2bar" pressure sensor, and it will only "read" up to 15psi.  If you run more than 15psi of boost, the stock ECU has no idea how much more.

We have had very bad experiences with the stock turbo carbon seal failing and shattering on the compressor housing.  When this happens, you get a lot of oil going into the compressor and lots of oil smoke out the exhaust.  The turbo will need to be rebuilt.

The stock ECU will overboost fuel-cut on you at approximately 1psi over stock.  It is not recommended to bang against this fuel-cut.  Blown motors have resulted from doing this repeatedly.

Consensus seems to be 10psi to 12psi of safe boost with the stock turbo and the stock (top-mount) intercooler.  This is very good advice.

I have run up to 14psi on my FC with very little trouble, but I do run an Walbro 255lph upgrade fuel pump, 4x720 fuel injectors, a Field SFC-HyperR fuel controller, a G-Force Engineering reprogrammed ECU, and an A'PEXi Super AVC-R to control the whole mess.  I do not recommend other people doing it, but it can be done.


-Ted

 

is that safe with 87 octaine, or does that baisicaly require stock timing to prevent detonation?

 

I recommend running the highest available octane you can get locally when trying to mess with advancing ignition timing.l


-Ted

 

How about putting an ignition controller on only the leading plugs, and only advancing them? (Can the Hi-6, for example, do that?)

 

No, the HI-6 cannot do that, nor do any of the other CDI boxes out there...that I am aware of.

The only easily installed ignition computer is the A'PEXi Super IT-C (do they even make it still?), which can control all 3 ignition outputs from the ECU.


-Ted

 

you could run the msd box and then the addon timing controller but is it really worth the money?

i would wonder if the cost of premium fuel is also worth the extra 5? max hp that you might get, along with the cost of a reduced margain of safety (on turbo motors in particular)

doesnt carbon buildup also significantly increase when premium fuel is used?

 

Ted, could you please explain for me, or provide a link; why is advancing both plugs at the same time bad? And the advantage of trailing vs the leading?

 

Base ignition timing has the leading plug firing 5 (measly) degrees before TDC. As rpm builds, timing advances significantly so the the leading plug is firing well _before_ TDC. The resulting flame front takes time (milliseconds) to propogate enough to make the big 'push' on the rotor - with the rotation of the rotor also occurring during those milleseconds, it should all happily occur at or just after TDC.
You can see the problem if you over-advance, or have a fast burning (low octane) mixture - and the push happens before TDC

 

Um, I'm a bit confused on your question...
Did I mentioned anything about doing this?


-Ted