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Tuning Timing...

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Tuning Timing... Register Help Home Forum New Posts FAQ Calendar Community Groups Reported Items Top Posters Forum Actions Mark Forums Read Quick Links Today's Posts Contribution Actions Contribute Blogs What's New? Contribute Advanced Search Forum Toyota MR2 Generations MK 2 MR2 - SW20 MK2 Stand-Alone EMS and Nitrous Discussion Tuning Timing...
If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. Results 1 to 6 of 6 Thread: Tuning Timing... Thread Tools Show Printable Version Display Linear Mode Switch to Hybrid Mode Switch to Threaded Mode 06-05-2008, 11:57 AM #1 MR2TuRbZ View Profile View Forum Posts Private Message View Blog Entries Visit Homepage Local V8 Killer Join Date Jun 2005 Location Indianapolis Posts 550 Thanks  8 Thanks  7 Thanked in7 Posts Total Contributions For
MR2TuRbZ     $ 0.00 Tuning Timing... I have tuned my car a little bit on the stock turbo and slowly advanced timing.

Now, i have a CT27, HKS 264 cams (degree'd), 1kcc injectors, and a trunk mount IC.

I can do fuel, thats the easy one

What is the best way to tune ignition timing? I will be doing a little bit of street tuning then finishing it up on the dyno.

Oh yea, its on a AEM EMS.

Thanks!
-Damon '91 Turbo MR2
13.51 @ 104 spinning with a 1.999 60ft
'92 Turbo MR2 (Sold)
13.92 @ 97 DD, fully loaded leather T-Top
'90 Celica Alltrac (Sold) Reply With Quote 06-13-2008, 02:38 PM #2 Enthalpy View Profile View Forum Posts Private Message View Blog Entries EMS Harmonizer Join Date Feb 2006 Location Denver, CO Posts 1,228 Thanks  8 Thanks  58 Thanked in45 Posts Total Contributions For
Enthalpy     $ 0.00 Street tuning the spark timing is asking for trouble. You are trying to pick out a torque regression in a sea of noise coming from wind and all sorts of other sources. You use accelerometers and do opposing direction runs, but you still have a ton of signal noise. Doing this is like trying to hear your elderly grandma from across the room at a frat party. And no, you can't just tune for detonation.

To do it right, use a dyno. To get close, but not guaranteed optimal, street tune it and hope you don't hit a semi or get a ticket. Reply With Quote 06-13-2008, 04:46 PM #3 MR2TuRbZ View Profile View Forum Posts Private Message View Blog Entries Visit Homepage Local V8 Killer Join Date Jun 2005 Location Indianapolis Posts 550 Thanks  8 Thanks  7 Thanked in7 Posts Total Contributions For
MR2TuRbZ     $ 0.00 I plan on doing it on a dyno... what i'm asking is what is your technique.... say you have a good pull and no knock is shown.... what is your next step in advancing the timing? How much, and where on the map?

Thanks! '91 Turbo MR2
13.51 @ 104 spinning with a 1.999 60ft
'92 Turbo MR2 (Sold)
13.92 @ 97 DD, fully loaded leather T-Top
'90 Celica Alltrac (Sold) Reply With Quote 06-13-2008, 05:41 PM #4 Enthalpy View Profile View Forum Posts Private Message View Blog Entries EMS Harmonizer Join Date Feb 2006 Location Denver, CO Posts 1,228 Thanks  8 Thanks  58 Thanked in45 Posts Total Contributions For
Enthalpy     $ 0.00 At a high level, you set the fuel with known-conservative spark, then advance the timing. Initially do it by a few degrees, then as you approach optimal, slow down. You know you are approaching optimal by keeping old runs on the dyno screen and doing a "power vs. advance" estimate. Do each run at the same temps (can't stress this enough). This is when I LOVE the huge cooling I have on my dyno! I can properly tune much faster than a shop that has no cooling. I have a blower that pumps 45 mph outside air through a 3' X 3' hole straight onto the intercooler and radiator. I have a separate blower for side-mounted MR2s.

You will either hit knock or a spot where torque flattens out and further timing advances don't produce more torque. Obviously, set the timing just shy of this limit. If you hit mild detonation, stop and back off a few degrees. Do this using runs at full throttle, and load-holding at part throttle.

Reset the fuel if your indicated AFR changes. That usually means you started with excessively conservative timing to begin with, and timing changes are actually changing the chemistry of the exhaust or the temp of the probe.

This can also happen if you don't know how to set an air temp offset curve, or if your IAT isn't placed in the correct spot. I flat out refuse to tune a car with the IAT placed pre-turbo. Even clever algorithms like what Autronics use can't completely compensate.

For expected hill racing (I live in the mountains), I will load-hold and purposely heat soak everything then set the temp offsets to keep things safe. I usually like to see EGT data when doing this.

If 1/4 mile racing ONLY, don't worry about part-throttle at all. It's wasting the client's cash. If road-driven or course-racing, set the part throttle spark and fuel.

I personally charge more if the customer wants ABSOLUTE perfect drivability. This requires multiple days to get right (cold mornings and warm afternoons). In one day, I can deliver good drivability, but to perfectly dial in things like cold start, you have to have it multiple days. Reply With Quote The Following User Says Thank You to Enthalpy For This Useful Post: MR2TuRbZ (06-13-2008) 06-13-2008, 05:50 PM #5 MR2TuRbZ View Profile View Forum Posts Private Message View Blog Entries Visit Homepage Local V8 Killer Join Date Jun 2005 Location Indianapolis Posts 550 Thanks  8 Thanks  7 Thanked in7 Posts Total Contributions For
MR2TuRbZ     $ 0.00 haha, i see you made the same post on the other board

When you advance timing, do you do it across the whole rev band? or just in patches? '91 Turbo MR2
13.51 @ 104 spinning with a 1.999 60ft
'92 Turbo MR2 (Sold)
13.92 @ 97 DD, fully loaded leather T-Top
'90 Celica Alltrac (Sold) Reply With Quote 06-13-2008, 11:12 PM #6 Enthalpy View Profile View Forum Posts Private Message View Blog Entries EMS Harmonizer Join Date Feb 2006 Location Denver, CO Posts 1,228 Thanks  8 Thanks  58 Thanked in45 Posts Total Contributions For
Enthalpy     $ 0.00 It depends. I'll usually note where the dips first appear as I advance. I will also watch the tach if I start hearing trace knock splats. Engines usually want a fairly smooth spark curve unless you expect certain air pressure resonances to set themselves up. The only engines with really strong resonances are racing engines designed to do so. Reply With Quote « Previous Thread | Next Thread » Posting Permissions You may not post new threads You may not post replies You may not post attachments You may not edit your posts   BB code is On Smilies are On [IMG] code is On [VIDEO] code is On HTML code is Off

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