Intake Air temp

I Did a drive in city trafic today while datalogging.  Outside temp 15 degree celcius.

When I started engine was 25 degree, air 14.  Then I see engine steadily rising to 110, intake air is 20 now.

Engine 120 degree, intake air 24 degree  After that, engine is not warming up more, but intake temp went to 27 degree/ Outside air not more then 17 degree.
All in a ride of 20 minutes.

So the intake under the seat, gets a lot of warm air from the engine. Not good for power.
This is with the stelvio, but same config as a GRiSO.

Map is from Beetle

Perhaps I should do a run with PADS and look at the results on a GRiSO? Thing is what can we really do to change the situation? Air scoops up the front? Forced induction and an intercooler? And really at the end of the day what sort of losses are we going to be looking at? Would we even notice in normal road riding? My guess is as long as the temperature compensation tables are good we'd never know! Interesting to observe though.

Pete

This is interesting. How were you logging the intake air temp?

Fresh air is drawn through the vents near the seat and from under the seat. The air box will get hot from the engine, and air passing by it at low speed will of course be warmer than ambient. I've removed the snorkel to allow me to easily store the bluetooth dongle and all the extra bits for the logging devices I use, which likely allows warmer air from near the air box to be mixed with the cooler ambient air. The air box is going to heat up regardless of how cool your incoming air is, but  obviously a cooler input would minimise any impact.

The question is, how badly does it actually impact? Your tests were in town at low speed, I would think at highway speeds it's a moot point because you have cooler air rushing past everything. It may be worse on a hot day, but then there's nothing to be done about that anyway.

beetle wrote:

It may be worse on a hot day, but then there's nothing to be done about that anyway.

We could move the planet further from the sun ....

Sorry, I'll get my coat.......  

Pete

Or move to Siberia. I hear it's always pleasant there.  

Not sure if this was a related issue or not, but one thing I noticed on a ride today was a bit of popping on overrun with minimal throttle while engine breaking.  No popping at all when the throttle was completely shut while engine breaking.  Popping generally occurred between 3500 and 4500 RPM while decelerating on maybe 3-7% throttle.  Ambient temperatures ranged from 18-22℃ and at elevations from 1300 to 5300 feet.

This was on the latest distributed map from Mark.

Not saying it needs fixing, just some more data.

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The problem is if the air temp-pressure table is incorrect then depending on what the weather is doing you could be getting 10% extra fuel. So if you map the bike at 20c the fueling will change either side of that. With the lambda off I reckon the air temp-pressure table could be set at zero trim (1.000) for 7-30c/956-1024mb range with no problems (although I haven't gone that far). We managed this ok with carbs.
On the subject of popping before my 1200 2v engine remap the bike would only pop when the weather got above 15-20c when the mixture was leaner but of course fuel consumption decreased accordingly. It used to do my head in nothing was stable from one season to the next here in the U.K.
I checked my changes with a AFR meter out on the road and everything was fine.

Not with the map that Steak has. At those pressure/temps, trim will be ~0.93. I have erred on the rich side, and injector pulse-width will be greater than zero on the overrun until revs drop below 3250 & TPS=5.8.

If the map compensates like it should, for running there will be no problem, but what you have is 10 degree hotter intake temp as outside temp is. If that changes when outside temp goes to 30 degree I have to wait until we have that here.  Anyway, the hotter the air is, the less power you have. Thats why they have intercoolers on cars. On stelvio and GRiSO there is no way that you can get front/fresh air to the back without seeing it. The tank is the big problem here.

One guzzi that has it fixed is the Alba, with long air scoops to get air at the back.

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Air scoops at the front? Maybe. Thing is are the power benefits delivered by the cooler air going to outweigh the downside of added weight? On that Alba thingie the scoops are picking up supposedly cool air from right next to the header pipes. That to me would seem to be almost the ultimate exercise in futility! As for intercoolers they are only of benefit on a motor with forced aspiration. With a naturally aspirated motor one would be pointless dead weight!

Pete

Having ridden in +30 temperatures quite recently, if power was down due to the heat, my arse-dyno coudn't detect it. Really, what power difference are we talking about, 1%? 3%?