2007 Exige S Intercooler Air Flow Study

[shay2nak]

check out this pic of an Exige S whose rear clam was fettled... Looks to me you guys can go even further to open it up... maybe where i circled and maybe on the inside of the opening there's a few more mm to grind away?

[shoco]

The hybrid solution you speak of: I tried that once and didn't feel there was enough room. But, hey I could supply you with side panels and hoses and you could experiment.

And I notice you are in San Diego? I would love to brainstorm with you. Just spent the last couple days perfecting a filter that saves Chrysler minivan transmissions from self destructing. Let me know if I can supply anything you need.

[Mr. Know]

Originally Posted by shoco

Just spent the last couple days perfecting a filter that saves Chrysler minivan transmissions from self destructing.

They do it almost like clockwork. The one we had installed under warranty was no better (and sounded horrible) so we traded ours in immediately.

[apk919]

Originally Posted by shoco

The hybrid solution you speak of: I tried that once and didn't feel there was enough room. But, hey I could supply you with side panels and hoses and you could experiment.

And I notice you are in San Diego? I would love to brainstorm with you. Just spent the last couple days perfecting a filter that saves Chrysler minivan transmissions from self destructing. Let me know if I can supply anything you need.

Yes, my Lotus is in San Diego, and as of now, so am I. I would be interested in trying out the panels and hoses... it might be a couple of weeks before I'm ready to get to that stage... I'd also like to see your mod in person too.

Originally Posted by shay2nak

check out this pic of an Exige S whose rear clam was fettled... Looks to me you guys can go even further to open it up... maybe where i circled and maybe on the inside of the opening there's a few more mm to grind away?

It's hard to see the way the ductwork is attached to the clam, but there's not too much you can grind away in the area you indicated. Here are pics from the "fettling" so far:

1) Before fettling... rubber snorkel is disconnected and a light is shining in the gap.

2) Beginning of fettling... you can see how much material I'm removing

3) After fettling (for now). Road test tomorrow...

EDIT: Note that the rubber gasket on the clam's inlet has been removed... the Cup roof has a gasket on the mating surface already, the stock S roof does not. I moved the gasket from the clam to the stock roof for testing purposes...

[IamBatman]

can you show a pic of the tool you use to fettle the ic intake?

[apk919]

Originally Posted by serpentor

can you show a pic of the tool you use to fettle the ic intake?

Fettle with the Dremel, FTW!

BTW, the LED light attachment (as shown below) is very convenient for fettling.

[Bgwilly31]

GREAT Thread.

APK and the rest of the contributors keep up the good work.

[Smoky]

This is the best thread EVER!


Semi-tangent to the earlier tangent.... Shoco: I had considered another option, and with you and APK in the same place I thought it would be a good time to bring it up.

Do you think it would be beneficial to run the roof scoop to the airbox (where the snorkel currently enters)? Then one could take Shoco's side-inlet kit to improve airflow over the intercooler, and the roof duct could then be used to provide cool, clean air to the airbox.

I've looked at my engine bay a bit and even with the i/c installed it seems like there is enough room for a few bends and flex pipes to run the plumbing and it shouldn't interfere with opening the hatch either. The airbox doesn't need a massive amount of air going to it. It just needs access from which to pull cool air, and enough of it circulating around. Just curious as to whether or not you think this is a good idea, based on both your experiences in evaluating airflow through the roof scoop.

And Shoco, any plans to make a kit which will work with the rls intercooler? I'm very interested.



Back on topic: keep it coming! Can't wait to see the data after the fettling is done, to see if it makes a diff.

[Bgwilly31]

Originally Posted by Smoky

And Shoco, any plans to make a kit which will work with the rls intercooler? I'm very interested.



.

I dont think he made a sellable kit for the stock I/C did he?

[shoco]

Bgwilly- sorry you feel that way. But , yes I do,did,would,could can and will keep on.

Smoky- Yes , you could use the roof scoop for the airbox as size/flow is compatible and it might even sound fantastic. I never tried it as I sold the car in Dec and am playing the metals market with the money. Miss it .

APK - anything I can do to help, let me know. I will supply anything I have to save you time/trouble/expense. I am interested in data points that show conclusively which configuration would cool the best whatever that may be.

[apk919]

Originally Posted by shoco

APK - anything I can do to help, let me know. I will supply anything I have to save you time/trouble/expense. I am interested in data points that show conclusively which configuration would cool the best whatever that may be.

Thanks... do you have your car (or a car) set up with your ductwork? I can fairly easily log data from any car with a standard sized intercooler. All the equipment is portable and easily configured. Maybe we could do a baseline with your configuration

[apk919]

One of the things I had briefly mentioned was the need to calibrate the air flow meter... I set up a blower to force air into the roof scoop, and then took readings from the back face of the intercooler. Dividing the face into 15 segments (5 wide by 3 high), I took flow readings (in fpm) at all 15 segments, then a flow reading from the location that the meter would occupy during the rolling test. By averaging the readings, I could estimate the volumetric flow being forced through the intercooler by the blower by multiplying the average fpm by the area of the intercooler (0.6076 sqft.). Then the ratio of the average flow to the meter location flow would give me a correction factor for the logged data, i.e. if the average was 283.5 fpm, the meter read 374 fpm in its logging location, I'd have to apply (283.5 / 375) * 0.6076 to the logged fpm readings to approximate cfm through the intercooler.

Below are the calibration matrices for the pre- and post- fettle calibrations. Notice that after fettling that the average flow is higher, and better distributed across the face of the intercooler. I also tried two positions for the meter during the post-fettle calibration... the original pre-fettle position, and an alternate position that gave the same static flow as the pre-fettle position

First (left) image: Calibration matrix before fettling
Second (right) image: Calibration matrix after fettling (with alternate sensor position)

[Pestodude]

Originally Posted by Smoky

This is the best thread EVER!




Do you think it would be beneficial to run the roof scoop to the airbox (where the snorkel currently enters)? Then one could take Shoco's side-inlet kit to improve airflow over the intercooler, and the roof duct could then be used to provide cool, clean air to the airbox.

I've looked at my engine bay a bit and even with the i/c installed it seems like there is enough room for a few bends and flex pipes to run the plumbing and it shouldn't interfere with opening the hatch either. The airbox doesn't need a massive amount of air going to it. It just needs access from which to pull cool air, and enough of it circulating around. Just curious as to whether or not you think this is a good idea, based on both your experiences in evaluating airflow through the roof scoop.

Smoky, I love this idea, if it's doable. I'm having the Proalloy chargecooler installed (Sector 111 is using my car as the fitment test mule). I'm thinking, hmm, now I've got this scoop on the roof in cool air doing nothing. Maybe I can direct the flow into the airbox. Would it f up the fuel/ air ratio I wonder?

[apk919]

And now some results...

First, it was not a good day for data logging... it was gusty enough to cause a lot of noise in the data. Second, I tried two different locations for the air flow sensor, as mentioned above. The first location was identical to the pre-fettle sensor location. I actually got slightly lower flow, but that was anticipated because of the changed calibration matrix. The second location was chosen to give the same flow during the static calibration post-fettle as the first location gave pre-fettle. That gave higher flows. But once both locations were corrected by the calibration factors, the results were close to identical (as they should be).

Basically the amount of fettling so far has increased flow over stock by about 20%. I'm not particularly happy with today's data though... so more investigation is in order. On the other hand, 10 minutes with a dremel tool and you get at least 20% more air through your intercooler. Not bad, but I'm not done yet. Also, I noticed during the static tests that some air was escaping from under the roof/clam interface and along the clam's rain gutter. More room for improvement.

Note: The vertical axis on the previous graphs were in fpm... those below are in "corrected" cfm (as per discussion above)

Graph 1: pre- and post-fettle data with original sensor location post-fettle
Graph 2: pre- and post-fettle data with alternate sensor location post-fettle

[Smoky]

Originally Posted by Pestodude

Smoky, I love this idea, if it's doable. I'm having the Proalloy chargecooler installed (Sector 111 is using my car as the fitment test mule). I'm thinking, hmm, now I've got this scoop on the roof in cool air doing nothing. Maybe I can direct the flow into the airbox. Would it f up the fuel/ air ratio I wonder?

I don't see why it would. It's basically the same thing as placing a filter into a cold-air position (like AEM does with other cars). Except in our case one is bringing the cold air to the airbox, rather than placing the airbox (and an open element) into the air (such as a fenderwell).

No pressure change would occur. Just the air source. And any rain that would enter the scoop would get trapped on the sides of the ducting and evaporate long before it reaches the airbox entry.

The engine would get the same amount of air as before, just ambient temp air. The ECU is well able to adjust for air at ambient temps flowing past the MAF. That would not be a problem.

It would just a be a cleaner, cooler source of air. If anyone knows someone who could take the OEM hood scoop bellows and mod it or use it as a template to create a modded version, one that captures the scoop air and funnels it down to a port, then the next few steps (tubing/plumbing to the airbox) would be fairly straightforward.

Perhaps we could pool resources and make it happen. Test it on our cars. See if it makes a difference one way or the other.




apk the graphs are fantastic! Really clear data. Very, very cool to see someone going through with real data collection. You're a true Mythbuster!

Any chance of throwing in the non-cup roof (Exige S) into the data? Do you still have one available?

Thx for the great reporting!

[apk919]

Originally Posted by Smoky

apk the graphs are fantastic! Really clear data. Very, very cool to see someone going through with real data collection. You're a true Mythbuster!

Any chance of throwing in the non-cup roof (Exige S) into the data? Do you still have one available?

Thx for the great reporting!

Thx! I've been getting better/faster at swapping roofs... but I think that I'm going to wait until I've done more fettling, etc. before I swap the stock roof... but that is in the plan... (and yes, I have access to both the Cup roof and the stock Exige S roof)

[ozracer]

Awesome job guys. Taking into consideration heat soak or intercooler efficency could there be any gains through the use of thermal coatings to the ic unit to reduce temps. It works for exhausts could it provide further gains in conjunction with this fettling?

[Ade]

Nice work, 2 things I would add, first have a stainless heat sheild made to go between the IC and the engine to remove the heat soak from the engine, second the problem with making the roof scoop into the air filter duct will come about when you try to remove the old ducting from the clam, it is bonded on. I considered this after I fitted my charge cooler and then dropped it after fitted the Lotus Sport uprated airbox as I felt that mod would then have no benefit.

[...m...]

...i'm interested to see comparative data using side scoop intakes...i've wondered how cool the air really is coming into the exige roof scoop by comparison to other points along the body - i know that when i put my hand out the roof of my elise at speed, i can feel all that radiator heat in the laminar flow licking up and over the roof...

[jasondew]

Originally Posted by ozracer

Awesome job guys. Taking into consideration heat soak or intercooler efficency could there be any gains through the use of thermal coatings to the ic unit to reduce temps. It works for exhausts could it provide further gains in conjunction with this fettling?

a thermal coating on the IC will reduce it's ability to cool the charge air. it works both ways.