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Probably not ideal but then with there plastic manifolds they probably heat the intake charge less to than the old Holden V8 intakes.....

As I understand it for the LS engines the MAP functions are a back up to the MAF, I don't think it was the intention of the original designers to run the engine MAP only.

you need to also take intake reversion into account. That alone on a big cam engine makes the apparent intake temps sky high.

When we did the Big Gs VH we put it in the plenum spacer and the stability of the MAT verses intake runner actually worked far better than factory setup. Only needed to move a few point on the inverse temp table and the wide band vs charge temp was rock solid and predictable and because the engine had no thermostat we manually controlled the temps via the dyno fan so temps swung from low 60s to over 100c and it was stable.

This in contrast to my old VP inverse temp and contribution table tuning for stock engine was a head fuck due to the post shutdown heat soak and fudged factory tables to try over come this.

hehe I have never put an ecotec MAT sensor in the runner actually. mostly from sheer laziness but they always go in the plenum.

honestly I think thats the best spot. With reversion in the runner you effectively are reading the exhaust temps mixed with recirculated intake air not fresh charge air so that ends up with the cam/intake characteristic superimposing on the MAT temps than pure air charge temps

Dylan wrote:I've always wondered how the LS motors go with a MAFless set up. As the one's I've seen still run the IAT in the intake pipe. Is that best practice?

You can model the charge temp with tables, scalars and some math, the LS PCM is more capable of this sort of thing with its increased processing power. It even models coil temperature adjusting dwell to suit the conditions and not overheat them.

vlad01 wrote:honestly I think thats the best spot. With reversion in the runner you effectively are reading the exhaust temps mixed with recirculated intake air not fresh charge air so that ends up with the cam/intake characteristic superimposing on the MAT temps than pure air charge temps

Where does the hot air end up though? But I do agree on the placement not needing to be in a runner necessarily.

its blows up the runner upon valve opening and then back into the cylinders once the induction wave moves back down and vacuum starts to do its job. Normally the hot gases don't exit the runner unless the cam is terribly mismatched to the engine combo. At the tuned rpm band where intake, engine and cam all match up there is no reversion, quite the opposite. The wave comes down and pressurizes the bottom of the runner right when the valve opens. Natural force induction

The issue of hot gas reversion is usually just at lower rpm, idle etc on bigger cam engines but can be at other rpm bands where the cam isn't suitable for the combo.

My question was more a rhetorical one What I was getting at is it ends up back in the cyl so influences the density of the charge air.

so for anyone interested.... this is what 11P Spark cut limiter sounds like on a stock VR V6 at last sundays casino drags.
we configured it so that it mangs on economy mode and spark cut on power mode LOL.... lots of confusion to watchers, he was dropping it in and out of power mode during the burnout.

[youtube]https://www.youtube.com/watch?v=hW_3mKqKu5w[/youtube]

Sounds good on the spark cut!

Just wondering if the injection delay table for $11p is supposed to be similar to the end of injection in the MAF based systems?

If so wouldn't it be best to change so that zero is actually 80 in hex therefore we can alter the delay positive or negative to if the cam is changed either way?