CivicTail project: ginormous aerodynamic tail on '07 Civic sedan

[freebeard]

Originally Posted by aerohead

I've heard of gasoline engines with dual throttles,one for low speed,then transitioning to the secondary for higher power settings.I've never seen one,but it sounds like a good compromise.

Really?


http://www.edelbrock.com/automotive/mc/carburetors/94-series.shtml

these kits include straight throttle linkage and triple-deuce kits include our exclusive progressive throttle linkage #1033 originally designed by Vic Edelbrock Sr. back in the late 1950's for small-block Chevy.

http://jiminglese.com/weber5_009.htm

This is the standard twin progressive Weber DCOE system shown as shipped. It comes with a low-pressure fuel regulator, fittings, and base gasket.

This unit replaces any standard four barrel. The progressive linkage is important for economy, so it is standard on all the units.

I can't find an embeddable picture so they don't get the free advertising: 32/36 DFEV Weber Carburetor Two Barrel Progressive Carb, Electric Choke Linkage

[California98Civic]

Originally Posted by freebeard

... I can't find an embeddable picture so they don't get the free advertising: 32/36 DFEV Weber Carburetor Two Barrel Progressive Carb, Electric Choke Linkage

Is this it?

[freebeard]

Yes. That would appear to be it.

[aerohead]

I was referring to an EFI system which utilized separate throttle bodies.With an independent idle circuit.The primary throttle would handle low,to mid loads with a long (torque) runner,then transition closed as the secondary bore short,high-speed runner opened for Bahn-storming.
The idea was to have throttles which would always be near WOT.

[freebeard]

Ooops. I guess I thoroughly derailed a boattail thread.

Sorry.

[aerohead]

Originally Posted by freebeard

Ooops. I guess I thoroughly derailed a boattail thread.

Sorry.

In a way,it's very germane to the issue of Metro's low gain from the tail.And it's the 1st instance where we potentially see the issue of gear-matching/load-matching vs MPG from streamlining.
I think Darin's mods really lowered the CIVIC's drag.There's nothing in the public domain ever published which would debate that.But the mpg,as a consequence of the drag reduction is the sticking point.
And we have no way,beforehand,to predict how a particular vehicle is going to react.

[ECONORAM]

Originally Posted by Cd

Metro, before you remove the tail, could you please do a coast down test for us ?
With talk of the BSFC being a culprit, your mileage might not improve with the 'tail, but if the 'tail had a change in aero much like previous designs, it would certainly show an improvement in the length of the coast.

( I'm not suggesting you do it this weekend, but rather at your convenience before you trash the tail.)

You, sir are a scientist. Thank you for presenting the facts as they are. Something such as this could come as a huge blow to the ego, and it would have been easy to simply avoid this re-test all together, or make up some excuse.
By presenting the facts - no matter how depressing the results - you help us all.
Thank you.

Too bad I didn't think of it until now, but if BSFC was the issue, loading another 200-300 lbs in the car might have provided enough load to get some good tests.

[mathump]

If aerohead is correct, maybe the solution is to put in the CVT transmission to optimize load on the engine. Of course it may be easier to transfer the tail to an already CVT equiped civic. You can use my hybrid if you like. Still impressive as my unmodified hybrid gets 42mpg on average. Best I've seen is 55.

I'd like to see tuff tests on the kam and tail first.

[Fat Charlie]

Originally Posted by mathump

If aerohead is correct, maybe the solution is to put in the CVT transmission to optimize load on the engine.

Abdicating all control over how the power gets put down isn't a good move. Yes, it's more efficient in steady, predictable acceleration, but there's a lot more to driving than that.

[MetroMPG]

mathump: I posted some images of tuft testing in the "big build thread" for this Civic.



More discussion here: http://ecomodder.com/forum/showthrea...tml#post469951

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CVT:

I've since sold the Civic. But I'll get a chance to try out the theory when I repurpose the Civic's tail on my winter beater 2004 Prius. I'll be starting work on fitting it in a week or so.



http://ecomodder.com/forum/showthrea...ing-32497.html