different octanes on dyno...

[Mikael]

I really could care less what you have in front of you. The PCM has set tables to calculate spark. Temp, MAF, MAP, IAT, all that good stuff, then comes up with a number. Its won't say "hey, no knock yet, lets keep going." That's BS. What, they'd call it a LTST?


This is why there is a small aftermarket for the V6 f body, and why you guys never get any respect or why it took 10 years for a person to make a decent amount of power (which is still debat/able being on race gas w/ intercooler spray).

But heres a challenge to the people here.

Run 93 octane on stock spark. See how much your mileage goes down. Take it to the track before and after. See the times get slower.

[Magnus]

Hmm.. never once did I say the PCM will advance spark to the moon if it doesn't see knock nor did I say it will make its own table. Problem is, you have NO clue how high the tables are before correction.. all you see is autotap #.s. I KNOW how high those spark maps are and how high they can go. They are a lot higher than 87 will allow. The V6 has 2 tables just like the LS1 does.. Good luck getting the performance map to go with 89 or 87 octain. The low octain fuel map has a significant drop in timing over the good fuel map.

The average modder sees 22 degrees of timing at WOT. Good enough for 89 octain.. Now why is that? Chances are because they are using the crap fuel table.. the high performance V6 that's setup right will see near 30.. I have hundereds of autotap logs as well.. I know this.

This is not why there is a small aftermarket for the V6 f-body.. and not why we never get any respect. You have no idea what you are talking about.

FYI, I already did the challenge.. I ran 13.6@98 NA. Yea.. I was on 93 pushing 32 degrees of timing. Damn I'm such a fricken moron for not running 89. How could I be so stupid. :rolleyes: Cause we all know that 87 and 89 octain just LOVES timing advance.

[AMinor65]

You're right, Magnus! I've seen 28 degrees at WOT and as high as 34 at different times during cruising. All of this was during warm weather. All I use is 93 octane.

[Magnus]

Part throttle timing can reach over 40 degrees.. I never really look at that though. I only watch WOT timing.

If you use a MAF T+ to bump up timing (How I was able to push 32), you will NEED 93 octain or you'll get KR.

[Tyler]

ok.. im starting to understand now.


so after having 93 in my gas tank for a while.. my computer will learn to go to the better table.. thus advance the timing some? which will create more power.

cool. next trip to the gas station.. 93 will be going in

[Magnus]

Tyler, you have good flowing exhaust which will definately help. How is your intake and what plugs you running? If your intake is good and you have a decent set of plugs, using 93 octain should be enough to allow your PCM to use the more agressive timing map.

I have reason to believe many 3.8's use the less agressive timing map. Reason is, you see lots of guys posting that they see 22 degrees of timing and ask if its normal.

[AMinor65]

And if you need more proof, check out this "secret" ;) :
http://zzperformance.com/zzp/free_mo...ing_secret.htm

[Tyler]

Magnus. Yea my exhaust is mad free flowing.

intake should be here within a week. (SLP CAI)

im running the NGK tr55's self gapped at .060 (just got them shipped in today) and the taylor spiro plug wires.

i'll have them in my car tomorrow morning.

with the stock intake, i have an oem K&N replacement

[Tyler]

<blockquote>quote:</font><hr>Originally posted by AMinor65:
And if you need more proof, check out this "secret" ;) :
http://zzperformance.com/zzp/free_mo...ing_secret.htm<hr></blockquote>


i read that just now.. wow.. running 87 octane could be yielding us up to 22hp? whaaaaaaat.

or maybe thats just with gtp's

[Tyler]

also another question..

i am a hard driver. i like to floor it sometimes [img]smile.gif[/img]

but then again. i like to just cruise and save on gas mileage.(most of the time [img]smile.gif[/img]

so in order for my computer to switch its ways.. od i have to drive hard? or will it set just by cruising with the 93?

[Magnus]

If you want to save $$$ run 89.. if you watn max timing run 93. If you run with 89 and your pcm uses the low timing table, then you will need to run the tank low and fill up with 93.. your PCM will attempt to use the more agressive map to see if it can.. if your car can already get away with the more agressive map on 89, then you just may get some KR at WOT and not at cruise.

It all boils down to.. if you want max performance from a modded 3.8, run 93.. If you want to save $$$ and don't drive the car hard, then use 89.

[Tyler]

ok.. but my question.. does it take time for the computer to recognize the different octane?


like say im on E with 87. and the next morning i fill up with 93 octane and hit up the dyno about an hour later. will it still be on the low map instead of the better one?


i guess its time for me to get my laptop and order autotap

[Magnus]

It takes time/driving.. drive around town and vary your driving style and it will learn.

[Tyler]

cool..thanks for the quick answers

[myrelease]

What would you suggest a stock 3.8 Fbody to run to get the most power? I have a stick, if it means anything? 87, 89 or 93?