IAT sensor trick

[Darknight]

I have the Series I 3800 (NOT the pre-1988 3.8 but a REAL 3800 - people are always getting them confused.) which has the 9:1 compression ratio, unless I am deceived. The Series II has 9.6:1, of course. I have tried the 4.7k resistor, the 10k resistor, and now I have pushed the envelope a bit further. Due to my lower CR, and the fact that I use only 93 octane, I decided to try a little more spark advance. Well, I put a 10k and a 4.7k in series, for 14.7k of resistance. Given that the 4.7k imitates ~ 60*, and the 10k imitates ~ 30* air readings, I extrapolated that a 14.7k would imitate ~ 0* intake air temp.

It seems that for every increment of close to 5k ohms, the temperature reading goes up or down by around 30*. This is not exact, but it's close.

Oh, about the performance...the car definitely feels quicker, and accelerates longer into 2nd, and picks up 3rd some better. I still have to try some stopwatch times.

I wouldn't recommend this for the second series 3800 due to the higher CR unless you've got a good cai setup, 160 thermo, and no fuel supply problems, and running high test gas, of course.

Now, if it's close to 0* outside, I suspect you wouldn't have any trouble, but running it then would pretty much be useless, haha.

DK

[ August 03, 2003: Message edited by: Darknight ]</p>

[merlinsrealm]

the problem with this tricker is that after about 2 passes at the track or on the road the computer learns and the tricker isnt worth S!@#....You have to put it on...run at the track and then take it off. There is a big misconception about the IAT trickers. I have personally tried the SLP IAT mod and have had the scanner on the car running quarter mile passes to see the difference. THE PCM learns rather quickly.

Eric

[Darknight]

I don't see how it can relearn something that's hardwired in. It could retard the timing if it sensed knock, but that's the only way I can see it changing. I've run several WOT times today, no less that 5 or 6, and I've seen no change at all. Perhaps the Series II is more prone to detonation, or perhaps the computer is reacting differently. Remember, this is a Series I, with a totally different CR and computer. What year is yours? The 97+ computers behave differently from the pre97s, or so I'm told. I'd like to see some others with the Series II try it and see how it did. I believe people get used to a certain performance level after a few runs.


DK

[ August 03, 2003: Message edited by: Darknight ]</p>

[FirebirdGT]

Darknight - since you say you have a Series I but don't state your car anywhere I don't see your point to this post.

As for the 95+ 3800 Series II engines this is a worthless "mod". The IAT ONLY is used on initial start when the engine is cold and WOT. All other times the PCM is using the heated O2 sensors and ignores the IAT/MAF inputs.

The ONLY place this would do anything for you is at the track on a hot day.