SmaknaSS

iTrader: (1)

I have a 01 SS,I Installed FLP headers W/ORP FLP Y pipe on a basicaly stock car.I Then tuned my car Via MAFT & Efi live, My L'TRIMS are averaging -3,My WOT O2's are @ 91-90 MV, I have almost no KR,I pulled only 2 degrees of timing at the most during a WOT run once,My timing only advances to 20-23 degrees @ WOT. Before I installed My FLP headers my car felt much faster and while accelerating before My stock rear end would strike the rubber stops. Doe's any body have any suggestions on getting back some of that low end torque? Below are a list of some of my mods. (SLP RA,SLP lid,KN,180 DEG TS,MAFT,SLP MAF,bellows,TB by pass,TB stop mod,SLP fan switch,FLP LT W/ORP,SLP dual center mount exhaust.

Narcosynthesis

Add a cam <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

You probably lost a little low end torque but gained it up high with the headers. I'm no expert but thats what I expect happened.

Colonel

Your timing sucks if you're seeing no more than that at high RPM during WOT. Your mixture may be rich. ANY KR is more than you need. Don't settle for 2 degrees. Settle for zero.

CaptainSS

Gotta be runnin' rich. LT headers famous for causing rich burn but, get that right you will see a perf upgrade

niphilli

Running FLPs with cats I saw NO loss in Low end torque, actually a pretty decent gain from 2.5K all the way up. My car now feels stronger on the low end than the top end ???? Your 02 readings LOOK right on but they may not be. I would invest in a dyno tune with wideband, Predator or LS1 edit should do the trick. List your timing throughout the whole range. Optimal should be 29-30 up to around 3500 RPM and then 25-26 from there up. For each degree of timing you are leaving roughly 3RWHP on the table. You definately want to get rid of the KR also.

-Nick

SmaknaSS

iTrader: (1)

Thanks for the info guys, I'll check the timing through out the range and I'll possibly get some cat's untill I can afford an H/C setup, The funny thing is When I'm running WOT after running for 45 min, my L'TRIMS start out @ 95mv, then start to stablize after like the 3RD run to 90/91mv @ WOT within 1/2 hour run time. Also If I lean out my MAFT 2% more I get more KR, Am I rich or lean? I guess I need a wide band dyno tune before I get LS1 edit, I wanted to get & learn LS1 edit before a wide band dyno tune so that I can see If they tune it right, like not shutting off knock sensors or something to get rid of KR. Going over to the tuning section.

Colonel

"Optimal should be 29-30 up to around 3500 RPM and then 25-26"

You would suggest 25-26 degrees at high rpms? That's even less than stock in most cases. <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

niphilli

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Colonel:
<strong>"Optimal should be 29-30 up to around 3500 RPM and then 25-26"

You would suggest 25-26 degrees at high rpms? That's even less than stock in most cases. <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">U Sure on that one Colonel? I was told that this is an optimal street setup by my tuner. Apparently these engines like to start pinging and detonating around 3500 RPM so a little bit of timing should be pulled from 3500 up (30 Deg. being optimal for power)?? Correct me if I am wrong.

-Nick

<small>[ December 19, 2002, 08:49 AM: Message edited by: niphilli ]</small>

niphilli

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LBCSS:
<strong>The funny thing is When I'm running WOT after running for 45 min, my L'TRIMS start out @ 95mv, then start to stablize after like the 3RD run to 90/91mv @ WOT within 1/2 hour run time. Also If I lean out my MAFT 2% more I get more KR, Am I rich or lean? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">You may be a little lean. 90/91mv seems to be the "internet" optimal, but from what I have seen it varies from car to car. Anything under .93-.95 at 26 degrees of timing (above 3500) and my car started pinging <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> . Most now say that o2 readings at WOT are not that accurate. Unfortunately the Wideband attachment was not working correctly on the dyno the day my car was tuned. We had to go by where the car stopped pinging and KR leveled off to 0.

Hope this helps.

Colonel

Nick, it depends on several things...

Your coolant temp. I run a 160 with the appropriate fan settings.
Your plugs. I run TR-6s which are a little cooler than stock.
Your mixture. Too lean and you can't get away with as much timing advance.
Your gas. I run only 93 octane.
The density altitude. The higher it is, the less prone to detonation your car is.
And by far the biggest one...whether you have cats or not. I don't run cats. Cat's cause %90 of the real KR with these cars.

So, some people might only get away with 25 degrees where as others might get away with 32 degrees.

IF you can keep detonation at bay you will make more power with 30 degrees than you will with 26.

Also, ever notice that from the factory at WOT you get higher and higher timing advance as your RPMs climb (this assuming NO KR)?

<small>[ December 19, 2002, 01:59 PM: Message edited by: Colonel ]</small>

niphilli

Thanks for chiming in Colonel. I posted some questions about this earlier with no good info so I dug a little deeper and got some good decent info. When I first got the results from my tune on paper I was a little dissapointed with the timing drop at 3500 myself, my timing looked great up until that point (29-31). In my case though this is the best we could do in order to have no KR or pinging issues. From what I am told most all of the pre-00 cars exhibit this drop at around 3500 from the factory (reasoning behind was that GM did this to fight Detonation/pinging). BTW: My factory Timing tables ended up being pretty much dead on when it was all said and done. With 0KR my timing did not seadily increase throughout the RPM range though. Timing was pretty constant at 29-31 up until 3500, then pretty constant at 25-26 from 3500 up.

For some reason the timing maps I have seen in the '01s and '02s are horrible. I have seen multiple ATAP logs of '01s and '02s that experience the exact same thing that LBCSS is experiencing at WOT. Maybe these cars were a lil too potent and GM tuned them down a little? I have seen some excellent results from '01-'02 bolt-on cars being tuned with Predator/LS1 edit. Who Knows.

I guess the moral is that Timing and A/F vary significantly from car to car, best bet is to go to a dyno with wideband and use some sort of software to tune the car. It is not a bad idea to take your ATAP with you on the dyno to see what YOUR CARS o2 readings correlate to on wideband A/F. If only I had a dyno in the garage <img border="0" title="" alt="[Sad]" src="gr_sad.gif" /> .

Colonel- When you guys are tuning do you go with a little richer mix in order to up the timing a little, or do you just look for a happy medium? I am wondering which hurts power more, a rich mix or a decrease in timing? The two are so intertwined that it is hard for me to tell.

<small>[ December 19, 2002, 04:07 PM: Message edited by: niphilli ]</small>