Extreme front airdam - a test

[landspeed]

OK, I will be doing a semi scientific test tomorrow. I have just fitted a fairly extreme front airdam to 'Bluey II' (as well as a partial grille block and small rear wheel skirts - just the upper 1/3 of the wheel arch).

I never noticed a major difference with the last two, but I just went for a
quick test drive with the air-dam, and it seemed to be significantly more
economical.

Tomorrow, I am going to do a round-trip of 600 miles, and will see what my long-distance fuel economy is. I have some comparison tanks - I drove the same road a few months ago, in similiar weather conditions (actually it was a little warmer when I did the comparison tank). I'm hoping that the air-dam will make a significant difference to the economy on the journey tomorrow!

The total distance is 800 kilometres... It would be cool if I could do that all on one tank but I don't think that is possible. We will see...

I will post pics of the air dam + an analysis once the test is complete, later this weekend!

[Antares2k6]

I look forward to seeing those. Would like to see how the numbers work out. Anxiously waiting to see mpg for home made air dam.

Joel

[flydelsolsi]

Could you fiberglass or bondo a factory bumper to eliminate air pockets? Would it stick to a plastic bumper. That is an idea I have been kicking around.

[GasSavers_RoadWarrior]

Just "key" the surface well by crosscutting with 60 grit.

[landspeed]

OK, I will put photos up tomorrow (although I'm removing the airdam today as it has shown it is VERY effective, and I will start making a permanent one soon, with some improvements in aerodynamics.

I got just over 35MPG(us), in very suboptimal conditions (downhill at 110km/h with braking, and uphills so steep that the torque convertor unlocks. On my car it is a very 'slippery' torque convertor, so when it unlocks, the revs jump from e.g. 1900RPM to 2500rpm :O (causing a 25%-33% increase in fuel consumption with no benefit at all).

I accidently drove past my road on the way back, so ended up doing my 'commuting' run for a few kilometres. I could keep the Supermid at a 3.2ms injector pulse, and maintain speed, whereas usually (even when fully warmed up), I need 3.6ms. This was over a 2 kilometre stretch.

With Bluey I, the grille block did make a difference (and the rad block made a difference made a difference with Bluey II as well). The partial wheel skirts also probably made a difference - although I didn't notice it.

This air-dam, however, makes a ridiculous difference. The car sounds quieter when you drive, and you have to use noticeably less pedal to maintain speed. I think with my car, that aero-mods are the way to go. I think within the next few months I will have the second most extreme car on gassavers (and will save more fuel as no-one will want lifts in my car ).

Oh, and now I have nearly all the parts for a manual conversion (all the difficult to obtain parts). Also got a better exhaust manifold, two starter motors, and a spare alternator (which I think is going to be made into a wind turbine in a few weeks time, maybe to charge a 2nd-hand car battery, to charge my bicycle battery from ).

[dieselbenz]

I can't wait to see pictures of this thing.

[Project84]

My saturn has holes in the front bumper to allow air to pass on to the radiator and if I wanted to construct a good grill block, i'd have to cut into the bumper and remove some material that is in the way of making it a flush install. I'm worried about cutting it up for FE, but I have the material to install the grill block, and I'm kicking around the idea of an air dam too... this post has me thinking about my car more and more, I'm very excited to see pics of yours and read your FE improvement.

[landspeed]

Here is a pic of the car, during the final revision of the aero 'kit'



You can see partial rear wheel skirts, lower grille block (note, I removed the passenger side grille block, where the transmission is, due to engine coolant temperatures going too high). I actually just added the upper grille block (between the headlights) at this time. This was just prior to returning home on the journey. This configuration seemed to net slightly better MPG (but only about 1.5%), so this may just be random variation. I later removed the upper grille block as the air temperature went up later in the day. This made no difference to MPG, so the main frontal aero improvement seems to have been the air dam.

You can also see the front air dam. This was simply coroplast, duck-taped onto the front bumper, with three pieces of coroplast reinforcing it (braces) behind it. The centre one had a tube of coroplast reinforcing it. This held up to 62mph driving (70mph for a few minutes in total) without any problems, and also got grounded out a few times with no problems (except that it wore through the tape holding the reinforcing bars so I replaced this twice). Also note that it doesn't even go around the whole of the front bumper - it stops about 10cm short of the edge, reducing the efficiency of the airdam.

All this stuff has been removed now, but the mileage was amazing. The downside was the 'overheating' (it never overheated but went slightly above half on the gauge which I was not happy with). Once I get the manual gearbox, this will no longer be an issue (as I can generally use less petrol, producing less heat, and also do things like engine-off-but-in-gear coasting with the gas pedal held to the floor, and hot fans on full, for rapid cooling. You can't do this in the auto - and have to leave it idling down most of the hills to stop the bearings being destroyed.

So. the above was 'Version I' of the front air-dam + associated stuff.

Version II will be coming soon:

() Silver duck tape on hubcaps for cheap moon discs!

(a) Super Extreme Front Airdam (secondhand bumper from breakers yard... Airdam starting at the position of the numberplate (further forward), so even more air goes over the car instead of under (as it would 'lower' the point at which air decides to go either over or under the car. The airdam will also stick out forwards very slightly, so even more air goes over the car.

(b) Full rear wheel skirts (removable for tyre changes / tyre PRESSURES etc). I found this annoying when trying to pump up the tyres before the journey even with the partial wheel skirts but I was just lucky in terms of the air valve placement.

(c) Adjustable grille block (with manual choke cable as described elsewhere, on this site I think).

And then...

(d) Moderately extreme rear boat-tail as described earlier
(e) Wheel spoilers and boat tails
(f) Undertray later on

[theholycow]

Is it just an illusion caused by the rear wheel skirts, or is the car a lot lower in the rear than the front? Looking at the side compared to the road it appears that the rear really is low and the front is high. Was that done on purpose, or is it just normal wear and you don't want to waste money on new springs?

[ZugyNA]

Originally Posted by landspeed

All this stuff has been removed now, but the mileage was amazing. The downside was the 'overheating' (it never overheated but went slightly above half on the gauge which I was not happy with).

Strange thing about the overheating...because the air dam SHOULD help create a lower pressure area in the engine compartment...helping to "pull" air into the engine compartment?

Need to be sure the intake air isn't deflecting off the radiator instead of going thru it? If the low pressure area is in front of the rad (it is?)...the air might be going UNDER it? Make a crude duct? I think you want ALL air coming into the engine compartment to go thru the rad...and you want just enough air coming in to keep the temp gauge centered?

I'm sure you don't want the cooling fan running if you can help it. An indicator light on the hot wire to the fan will tell you when it actually runs...which should be only when stuck in traffic on a hot day?