Hey guys I am trying to figure out what is the best way to make safe power -- run more boost and less timing or less boost and more timing?

Currently I am running on pump gas (93 octane) 26 psi peak and tapering to 19.5 psi at 7000 RPM with 0 knock. I dynod (Mustang 500 series) at 315 / 315 with my catalytic converter on (mods in signature) and the torque curve was very straight at 315 from ~3500 - 6000 rpm. To get this boost curve to work on 93 we (Jestr) had to really pull a lot of timing out of the map....I am at 4* in the 3000 - 3600 range and 13* at 7250.

The question is would I be better off running like 24 psi peak and 18 psi at 7000 rpm and running a lot more timing? I guess my question is what would a few degrees of timing do for the power?

 

The answer is to test what your setup likes. I would set it so that each load zone has the optimal ignition timing that avoids detonation and then run a variety of boost levels and measure the acceleration or power curves and see where you cross over. Can do the same for MIVEC.

 

I am now a firm believer in lean AFR and retarded timing. Yesterday I tuned my friend's car. It is the car that I posted about HERE This is the car that Alfred @ TT, the pro "tooner" could not tune. I set timing very conservative and AFR was not too lean since we are on 91 oct and the point was to eliminate the knock.

The car loved this tune and produced a better power curve than with the advanced timing. I will now proceed to lean out the car ever so slightly and pull more power from it.

Your post re-enforces yet again the value of retarded timing and lean AFR.

I say keep your car as it is. If that is the setting that it likes, then so be it.

 

No , because the ECU will probably pull timing to a curve similar to what jestr did for you already but at 24psi




4 degrees is what I run at peak on an VIII at similar boost, tq, and power.

13 degrees seems sane at redline on a evo9 but 4 degrees at peak might be about 1 -2 degrees beyond power benifit from timing.

Keep in mind:

1. excessive timing changes true A:F
2. excessive timing may seem to produce power, but in truth the ecu pulls timing just below knock threshold so that 8 degrees on the mat is giving 4 degrees on the plugs (****** tuning)

 

[quote=C6C6CH3vo;4100319][quote=cij911;4100122]To get this boost curve to work on 93 we (Jestr) had to really pull a lot of timing out of the map....I am at 4* in the 3000 - 3600 range and 13* at 7250.
Another convert to the Klaus Almendinger school of tuning The word is spreading and pretty soon the "Buba" school of tuning will go the way of the Dodo bird

 

Bubba,

or Schultz

I dropped out of bubba just in time and enrolled to K A school

ECU has more important thing to do than tie itself up fixing the timing your feeding it

 

I am not arguing the importance of running maximum practical timing (what the engine needs) because I agree 100%. I am curious about this comment though, do you mean pulled out of the blue (as in no knock but less timing) or after or near a knock event?

I am running 2-3* at 25psi peak and the engine feels great, I am hitting 14 near redline with no ill effects. I know in most engines once you start camming them the timing allowance changes, I wonder if an exhaust cam is enough to allow more knock free timing? When my GSC's get here the process starts all over again, but after having the HKS280 for the last several months I have noticed there are alot of things I do on my car that seems to work well that doesnt on other 9's.

 

These are good timing numbers. You are following the MTBT principle. You run mimimum timing for the best torque w/o knock and not 1* more than that. The "Bubba" school of tuning believe that if a little advance is good, then a lot must be better. And the "tooner" starts cramming more timing down the engine's throat. When the ECU starts protesting and pulls timing, the "tooner" gets flustered and starts block tuning, collapsing the high and low octane ignition maps in the hope that this will stop the ECU from pulling timing. When that does not work, the "tooner" starts making excuses blaming the performance parts on the car. When you fix those and the knock continues, he simply gives up, declares the car a knocker and stops tuning.

This actually happened to my friend.

 

Thanks guys....I guess I should be pretty happy with the tune since I have done several logs since then and am getting no knock and the car feels smooth and strong. I just was not happy with the dyno numbers (315/315)....Maybe removing the cat and putting on the test pipe would yield a few more ponies, but the top end goes flat a little after 6K rpm ( I am guessing the cat is killing the top end)....Thanks again for the feedback.

 

Dyno numbers do not mean much. What is important is the consistency of the dyno numbers. Basically, is the car putting the similar number consistently? Another factor is safety. Is the car producing those numbers safely? Your car seems to be doing that. It is strong and smooth. It is a happy Evo. There is nothing worse than a grumpy Evo. And forcing timing down the throat of an Evo will make it grummpy. Give it the timing that it wants and it will be happy.

 

NJ -- Could I send you a log to put into DLL and see what the power curve looks like with that program? It would be nice to compare different setups with the same 'dyno'...Thanks

 

send a log here I registered my dll and would be interested to see the dyno plot

 

"I am now a firm believer in lean AFR and retarded timing."

The post originally was about comparing the effects of boost and timing, but we've introduced AFR without being specific about what we mean by rich or lean. One man's lean is another man's rich.

e.g
93 octane:
3500 RPM w PSI x AFR
6500 RPM y PSI z AFR

Can you fill in wxyz to be specific?

Personally on my 9 I run:
93 octane:
3500 RPM 25 PSI 12:1 AFR
6500 RPM 21 PSI 11.5:1 AFR

Some say this is rich, some say it is lean.

Now I trust the Evo's knock control I simply advance it until the knock sum is always under 3, usually 0,1, sometimes 2. The way the knock routine works tends to introduce knock sums during spool up because it takes the differential of the knock noise (ie rate of change).

 

JCSBanks -- I am pretty much 11.5 from 3300 to redline (WOT)....Prior to owning an Evo I would have thought 11.5 to be fairly rich and leaving a bit of power on the table...That said, the car seems to be happy (knock free) at this AFR.

 

Thats a great thing to see on a US board, a good old British cuss! Though I'm sure others use the phrase, it sounds so like home For those that like alliteration, "tosser tuning" should sound good.

MB