SidewaysLS4

Check out this thread: http://www.ls1gto.com/forums/showthread.php?t=95873

I am thinking as these cars start pulling timing out above 95F looking at the IAT timing tables, maybe something like this would be good for us also. I know that when it is hot out, the IAT is even hotter on these cars, and kind of stays that way for a good amount of time after moving, might be something to look at. I need to do some cooler weather logging this weekend now that it is cooler around here to see how the IAT's are on my car.

BADDLS1SS

iTrader: (22)

Could just 0 out the IAT correction for timing up to like 130 degrees or something... thats all i did with HP tuners. I did the same for ECT as well, above 200 it would start pulling timing.

SidewaysLS4

Yep, that's an idea, do you log any KR when it is hot out with those pulled?

Edit: Would one get KR with too much timing or would it just hole a piston?

BigMikeGXP

Looks like a good idea to me. The one time I was watching the IAT it got to 150*F while sitting still at sonic. Then once I started driving it took it a while to come down... and this was at 11PM with about 80*F ambient temps.

Billiumss

iTrader: (11)

That table is there for a reason, for the engines safety against detenation.

Best bet is it either leave it alone or reduce the 1st 2-3 columns.

jimmyblue

iTrader: (11)

You're best off getting the "normal, good air" timing tight
and then using this IAT table (and probably ECT too) to
shave back timing as you discover ping at outlying temp
corners. That, and doing something about the incoming
air path / temps.

SidewaysLS4

I played around with the IAT retard settings a bit. Temperature outside ranged from 72 to 80, IAT's didnt want to drop below 105 or so no matter what. Took the retard setting down 50% from the 104 to 158 ranges, set the 95 range to 0, and even 1/2'ed the first ECT retard row for good luck, and did some runs. Some ok, some KR would show up, one high speed run lots KR's showed and got bigger as well. KR really showed up above 80 MPH or so, so that was a bit overkill. Timing would peak around 31 degrees or so, KR's would show up around 28 degrees and above 4000 rpm when they did show up. Looking over the runs it seems my engine likes 27 degrees and below max timing at WOT. My finely calibrated rear end accellerometer didnt really feel like there was much to be gained if anything running higher timing values. Seems around 25-26 degrees under WOT the car is happiest and quickest.

After testing various levels of IAT retard, I ended up 0'ing out the 95 degree row, and removing 25% out of the remaining rows up to and including the 158 row. No KR's, and seems lots quicker and more responsive than stock calibrations which drop the timing as low as a sluggish 20 degrees or so with high IAT & ECT. Under 'normal' operation (way hot IAT even though it is cool outside) WOT timing is 25-26, and the car runs out great.

I'm really considering doing a quicker responding thermister like in that GTO forum thread. It sure takes a very long time to cool down the intake temp, and I think that more timing is pulled where unnecessary. Should be interesting to see how that would work out.

Richiec77

iTrader: (3)

You won't put a Hole in the piston with a Little knock. You usually blow holes thru pistons when events are WAY out of wack or you are spraying some N20.

But, what knock can do is damage the ring lands and cause the piston to rock in the bore from an un-even pressure front caused by detonation. That's what you should be worried about. It can still take your engine out on ya.

Man. What is the best intake to use for these cars right now? Seems like someone needs to develope a cold air intake badly.

SidewaysLS4

I was almost thinking of going to Home Depot for some insulation to wrap around the intake system.

BigMikeGXP

I would settle for a warm air intake... be better than the near furnace like temperatures it inhales now.

But yeah the different thermistor might be a good idea. It takes about 5 minutes of interstate driving for the intake temps to reach about 10* over ambient.

SDfbody

Don't purchase the Intense FWI if you own a Monte Carlo. It won't fit on Monte Carlo's, since we have more fender bracing then the GXP's. The only way to make it fit would to cut the bracing out. I just ordered a cold air induction air box(http://coldairinductions.com/W-BodyL...ldAirBox.html), going to try that, maybe wrap some insulation around the intake tube.


Monte Carlo



GXP

SidewaysLS4

I did some more testing out my mods, and found that it would be a good idea to reapply the factory IAT retard settings (including the 95 degree row). Just to say I 'tuned' that area, I removed 10% for a whopping .5 to 1 degree reduction in retard specs. Reason for this was that was some more KR occasionally showing it's head during WOT runs on that particular day.

Another thing I did that seems to really help though is moving the fan activation scale 2 temperature ranges cooler. This way the fans keep the engine cooler when in traffic, etc., and therefore avoid hitting the ECT retard temperatures, which makes for noticably better response due to less timing removal. Kind of interesting how they have the fan activation temperatures mapped out like they are PWM fans, but it is really just 1 fan on at one 'percentage', the next one on at another 'percentage' if you look at the charts for the fans.

BigMikeGXP

I also thought that was kinda weird. 3 tables just for on/off function

SidewaysLS4

Probably a universal PCM, I hear the 'vettes have PWM fans. Hey, can we say we have a 'vette powertrain now?

svede1212

iTrader: (3)

Hmmm, just found this thread. you can read my whole thoughts on intakes here. i originally found the Omega thermistor probe when i was designing my intake. at the drag strip i can get within 5* of ambient within 3 seconds. i run speed density but even you MAF guys use speed density in throttle transitions. you need accurate temp readings for the computer to calculate fuel charge as it varies with intake air temps (different air densities) as well as timing adjustments. i figured that the timing retard table was there for a reason. give the car cold air, read it quickly and be done with it

Area47

move the iat sensor to the front of the filter. works better, gets a better reading.

thats just me

svede1212

iTrader: (3)

a better reading is an actual reading of what's beng injested at the TB. it that's what your getting then good, if not it's time to re-evaluate. the stock probe is very slow to respond. by slow i mean >30 seconds. that's important to me when racing as in a little over 12 seconds and it's over for me.

Frost

iTrader: (45)

Is it REALLY that slow to respond or are you just heat soaked?

I tuned a 99 T/A (assuming a similar IAT sensor) with a powerdyne blower at 7psi. These things have no intercooler! Look at the rocketing IATs in the first pic... The second pic shows methanol on that does NOT spray onto the IAT sensor but is very near it. Look at the second pic. The meth comes on at 2-3psi. The ambient outside temp was sweltering 99degF at the time of the logs.



WITH METH