2007 Exige S Intercooler Air Flow Study

[charliex]

the temperatures do come out of the tmap on the intercooler.

[qball]

Originally Posted by Mag

Asked him about the readings showed him the graph. To which he replied: the way my therocouples are set up now, it's taking the temperature of the pipe itself.

I was going to say that. You are getting heat transfer from the pipes to the probes.

Do what I did... get some flexible thermocouple probes and insert them between the pipes and the rubber coupler into the air stream.

I got K-type thermocouples that had 10' leads, so they would reach into the cockpit.

[qball]

Here are some charts. (I wasn't focusing on heat soak here... mostly the effectiveness of the IC at speed.

Ambient temperature was 92 degrees. Don't know the relative humidity.

The first chart is speed vs. Temp

Purple = Inlet
Green = Exit
Red = Delta T

This is a scatter graph. and 2nd-degree polynomial trendlines have been overlayed

You can see that at around 60-65 mph, there is a diminishing value of return of increased speed vs. Delta T (i.e., increased speed above 65 mph does nothing more to reduce IC outlet temps)

The second chart is a plot of a a run, with variable speeds.

The time is along the bottom and the speed charted in blue

Purple = Inlet
Green = Exit
Red = Delta T

Again trend lines have been added.

This shows basically shows the affect of heat soak through the run.

Also of interesting note is the time period between 55:03 and 56:07. Speed is relatively constant around 65-70 mph. There is a shift in Delta T below the trend line (more negative area below the trendline). I guess we're showing that the IC has maxed effectiveness, and is now just heating up due to the increase load from the SC and engine. Immediately after that, I decrease speed. (let of throttle) and the load on the SC drops. You can see that the Delta T across the IC is now above the line, meaning that it has a chance to catch up and cool off a bit since it's not under load).

(These are all just my opinions and assumptions. I am probably totally off)

I'll post the raw data file in a bit.

Karl

[qball]

Here is RPM vs. Temp

(also a scattered graph with 2nd degree polynomial trend lines)

If you ignore the 5500+ RPM data...

I am guess that this shows that at 3300 RPM (which is probably cruising RPM in various gears at various speeds), the Delta T plateaus.

Blue = IC inlet
Purple = IC outlet
Yellow = Delta T

[qball]

Here is the data table. (attached in Excel)

I had thousands of more data points, but the sampling rate (frequency) of my recording thermal probe device was a lot less then the OBD-II data collection program. So I'm only showing the data points where the temp probe corresponds (i.e., overlap) to data from the OBD-II port.

[charliex]

i wrote a quick convertor from my format to csv so its not perfick' but excel reads it ok, hopefully i didn't make any glaring errors..

[qball]

I am using this recording probe...

Extech EA15 Data-Logging Dual-Input Thermometer, Extech EA15 - at Test Equipment Depot

And this for the OBD-II data recording

Products

[Mag]

Originally Posted by charliex

the temperatures do come out of the tmap on the intercooler.

ok cool, that gave a scare wonder why it was left out of the obd2 pids. thnx

chalie & qball thnks for data

will post new data for comparison when sensors are sorted.

[qball]

If anyone has removed their intercooler shroud (the plastic piece on the back that connects the roof duct tubing to the IC, I'd be interested in buying it from you.

This is the piece that is siliconed onto the backside of the I/C

Thanks,

Q

[turbophil]

Nice. What were ambient temps during the tests?

Best,

Phil

[dmh]

Why are the speeds so slow and rpm so low?
What track are you testing on?

[qball]

Originally Posted by dmh

Why are the speeds so slow and rpm so low?
What track are you testing on?

Whom are you addressing?

If me, then the track is Highway 417.

Ambient Temp is addressed in my post.

If you are addressing CharlieX, then I have no idea.

[dmh]

Just curious...What is the point of testing on a public road when tracks are available for testing? Other than drivability and all-weather capability what can you test?

[apk919]

Originally Posted by dmh

Just curious...What is the point of testing on a public road when tracks are available for testing? Other than drivability and all-weather capability what can you test?

I'd love to have a test track down the road from me, where I could put in a test session whenever it was convenient, without having to rent the entire facility and/or pay large fees.

But I don't. I don't think too many people here do. When people do get track time, I'm sure they'd rather be driving than fiddling with sensors, laptops, dremel tools, etc. So until my budget is comparable to McLaren or Ferrari's, I'm going to test close to home, on the street, doing the best I can to get accurate, meaningful, and useful results without creating any dangerous conditions.

[charliex]

i tested on amongst other places, baker grade in the desert with ambient temperatures over 110F, its at least 15 miles long and a fairly steep uphill, i don't think there any tracks like that around here

[dmh]

NYC--Where else in the country do you have access to more tracks within an 8-hour radius than we do? Hell, Englishtown is $350 for the day!
Who cares what an intercooler does on the street as there are laws to abide by. It is only about racing on a closed course of some sort that matters.
(Lightning, Thunderbolt, Englishtown, Pocono, Monticello, Lime Rock, Watkins Glen, Summit Point, VIR, Mid Ohio, Nelson Ledges, Mosport, Mt. Tremblant, Calabogie, Shannonville, New Hampshire, Beaver Run,...did I miss any?)

[charliex]

the laws of physics apply on the street as well as the track., they're not magic.

[dmh]

Originally Posted by charliex

i tested on amongst other places, baker grade in the desert with ambient temperatures over 110F, its at least 15 miles long and a fairly steep uphill, i don't think there any tracks like that around here

...or here! But it still will not replicate the track. That is why race teams test on a track.
I am still lost on the entire street thing. So I best let it go.

[charliex]

race teams have plenty of cash, can get access to track testing and don't have to share with the guy doing odd data logging, they test on dynos and wind tunnels too, last time i checked they didn't drive dynos or wind tunnels around on a track.

i've tried getting into my local track to do testing of hardware and stuff, they're not even remotely interested and want me either to rent the track for the whole time, or go with a group which just doesn't work since when you're doing this sort of work you're stopping and starting all the time, and it just annoys everyone, plus you end up spending most of the time explaining what you're doing.

plus the track is relatively flat, changes a lot and its difficult to repeat the results, a great big long straight going up a hill is like a dyno with real air flow and you don't have to speed.


also race cars aren't usually street legal

[apk919]

Originally Posted by dmh

NYC--Where else in the country do you have access to more tracks within an 8-hour radius than we do? Hell, Englishtown is $350 for the day!
Who cares what an intercooler does on the street as there are laws to abide by. It is only about racing on a closed course of some sort that matters.
(Lightning, Thunderbolt, Englishtown, Pocono, Monticello, Lime Rock, Watkins Glen, Summit Point, VIR, Mid Ohio, Nelson Ledges, Mosport, Mt. Tremblant, Calabogie, Shannonville, New Hampshire, Beaver Run,...did I miss any?)

My Lotus is in San Diego... but I get your point, there are plenty of tracks within 300-500 miles...

Originally Posted by dmh

...or here! But it still will not replicate the track. That is why race teams test on a track.
I am still lost on the entire street thing. So I best let it go.

Obviously race teams never drive their car on the street, so street performance is meaningless to them. But not to me. They also usually have significant logistics support when at the track (spares, tools, etc.)

I don't disagree with the desirability of testing on a closed track... but street testing can be a useful, convenient, and economic alternative.