[TurboQueef]

Hi...

That is the proverbial question isn't it...

Here is the real deal... I have been StreetTuner-ing and using the dragstrip as my benchmark tool. So far, I have maximized boost/AFR and have been working on the timing. I am running GT100 (100 octane) lead free.

I have noticed:

• If I achieve a good launch (1.7XX 60') my timing advance is less than if I launch slow (2.XXX).
• With a good launch my ET is high 12's but my MPH is low (104.24)
• With a slow launch, my MPH is higher (105.XX)

So, the more timing advance I can hold at upper RPM gives me more MPH.

The technique I am using to get more advance is to bump up each cell above 2800 RPM that holds a value in all three dynamic advance maps (AB&C). I make small adjustments then perform a 4th gear "pull" on the highway. I datalog, listen and look for "KNOCK".

I have achieved an incredible amount of timing advance by doing this process over and over and I am now worried that I may have too much. My specific concerns is that I may not be hearing the spark knock and that my datalogger is not picking it up. NOTE: I can clearly hear spark knock in my Supercharged TOYOTA so I know my hearing is OK but I wonder:

• If spark knock can be heard inside the cabin of an STI (my exhaust is just a touch louder than stock)
• If someone experienced in tuning for max performance could take a look at my data log and give me your opinion about the total advance I am getting. Here is a link to my datalog: http://n8rws.com/4%2022%2006%20100%2...%20testing.zip

I appreciate your time and any feedback.

Thanks,

Jeff B

[WolfPlayer]

Hi Jeff,

I took a look at the 4th gear pull and for 100 octane I don't think it looks high. Generally speaking, a tuned STI will hit about 15d on spoolup and run 30 at redline ... with about 24 or so at 6000. In some spots of the curve, I think you might even be not aggressive enough. It seems aggressive around 4K and aggressive greater than 6K. But, that seems cool for 100 octane. You might be able to add a little more timing ... *might* ... but, all in all, it doesn't look to be on the ragged edge to me given that you are running 100 octane. I don't think I would add anything more to 6000+ though

t

[TurboQueef]

Thanks T..

Do you know if spark knock can be heard inside the STI?

jb

[drees]

Sounds like you need some sort of knock light or det cans. Bad knock can be easily heard with the windows up, radio off and stock exhaust, but with aftermarket exhaust it's harder. And it's best to catch knock before you can hear it as by that point the knock is pretty severe. At high power levels any audible knock will result in engine damage.

Timing is tough to tune well on the street/strip, you really need an adjustable load dyno w/knock light or det cans to do it right. The general procedure is to up timing until it either starts knocking or power stops increasing. Once you hit that point bring it back down a smidge. Wash/rinse/repeat for all load/rpm points.

[TurboQueef]

Originally Posted by drees

...Timing is tough to tune well...

Good info... thanks.. please help me confirm that my understanding is correct.. here is the key point:

• Considering that I am using StreetTuner (stock ECU) I believe if I get to aggressive the stock knock sensor will pick up knock and the ecu will retard the timing to a safe point. Is this correct?

Thanks,

Jeff B

[TheMadScientist]

Originally Posted by TurboQueef

Thanks T..

Do you know if spark knock can be heard inside the STI?

jb

On a forced induction engine damage starts before spark knock can be heard. If you can hear it it is extreamly bad.

TMS

[overdose]

Trap is always better with a crappy 60', timing looks fine for 100 octane, but it's way too rich for 100.... get rid of the catted downpipe and restrictive exhaust and you'll be rockin

Also consider getting alcohol injection to reap the same benefits as 100oc while using pump gas, we'll be doing a group buy soon.

The stock knock correction system is going to pick up ping way before it's audible, keep a close eye on your KC and expected dynamic advance

Also check your shift points, according to my graph i should be shifting 7k in 1st, 6500 in 2-3, 6700 in 4th and 6500 in 5th to keep it returning to around 5k every gear

[WolfPlayer]

Here is one of the popular theories about tuning spark ...

Slowly raise the values in DA A. Watch your logs. If the ECU doesn't use all of the DA A amount then you are getting knock. In that case, back the DA A down. If you always run the DA A amount ... then raise DA A slowly (1/2 degree at a time) until the ECU starts to take away that extra advance.

t