AeroMod Me! (1997 Acura CL)

[AndrzejM]

Originally Posted by ChazInMT

I'm not so sure a Kamm would help much without it being meticulously designed and built, and even then you might only get 5-7%. Reason I say that is your roof to rear glass transition area radius is freakin huge, there are papers done on this that show a big rear radius improves Cd a lot.

You don't need to design your kamm using rocket science just a common sense, aero template and remember to taper it to the back. And you can get good numbers from that Berta kamm coastdown test

[Weather Spotter]

Grill blocks
Smooth wheel covers
Side mirror delete. I have had mine off for 2 years and the inside mirror works great!
Belly pan
Kamback. Leaving room for a boat tail ( you might not have space now but you will want one someday)
Take the tires right to max side wall.

[ChazInMT]

Different cars have different aero characteristics to begin with, Andrzej & Weather had cars ideally suited for a Kamm, there was essentially nothing aero about where the air left the backs of their cars. This Acura has quite a bit going for it in that the top of rear glass area has a large radius, and I've seen papers that show this is great for reducing the Cd. I'm not saying it's ideal, but, without knowing what the air is doing, a half-baked attempt to "Fill the Wake" in the case of this Acura CL will end up hurting the Cd. A very well executed Kamm going all the way back to the tail lights and having the sides shaped correctly would be the only way a Kamm would be an improvement on what is already a fairly aero car. The sides would be key to getting it right. We all know how to do the top part.

I pretty much gave up on making a Kamm for my Civic due to this reasoning.

[2000neon]

I think Chaz is right here. If nothing else the rear of the Acura is pretty different than the BMW, WS's matrix, the fiesta or even my Neon. All the basic stuff would still apply though as you said, especially for the top.

If you're thinking of a kammback, I would suggest leaving it towards the end and do the other mods first like air damn, grill block, etc. The time and effort involved in building an effective kammback could easily be spent other places first.

[nbleak21]

Originally Posted by 2000neon

If you're thinking of a kammback, I would suggest leaving it towards the end and do the other mods first like air damn, grill block, etc. The time and effort involved in building an effective kammback could easily be spent other places first.

Good point. It is definitely time to do some front end mods, intake temps in the low 50s just isn't cutting it for FE, I had to P&G much more to maintain a reasonable average.

Anyone have a good reference for front nose cone designs?

[AndrzejM]

I think there is definitely area for improvement at the back of the car

[Sven7]

Nose cone may net you less improvement than the Kamm, actually. Block off those holes up front, get the wheels taken care of, then think about the rear end.

BUT BEFORE YOU DO ANY KAMM STUFF make sure you tuft test the rear window. If it has attached flow, as Chaz said, you may not even bother. It will not be ideal, but if it's there it may get you by. Depends how much you like to tinker.

For highway FE, I saw about 25% MPG increase without a boat tail, and 46% increase with one. With all we've mentioned in this thread you may be able to top ~35mpg on the highway at 60mph.

[serialk11r]

I saw a CL up close yesterday while walking on the street, I feel like the rear is probably slipperier than most cars out there...The sides taper in more than a lot of cars (especially from that time period), the rear window has some nice big radius turns on the C pillars and slightly tapers in. Maybe some tuft testing first to see how the air is behaving? Just eyeballing it I would suspect that the air reattaches at the end of the trunk.

I think CLs are extremely pretty cars, if it were me I'd go for areas that don't impact aesthetics first, especially since your mpg is not that bad to begin with. I would cover the bottom up and block the grille first. The rear bumper has a nice angle to begin with. You could also put some subtle fairings behind the rear wheels.

[RiderofBikes]

looking at it now with the template, doesnt look bad as i thought. I didnt have much time to look before with my kamm response. Maybe a few inch extention to your spoiler could make a small improvement.

Agreed with others on buttoning up the front, and front/rear belly pans. haven't seen what it looks like under the boot area, but if like other hondas i've seen, its a parachute. still not as big as mine.

With your CL lowered, i assume you've also made a roll bar change, and aligned everything properly. How is your chamber?

[YeahPete]

I would leave the spoiler as is. You could extend it or whatever but I dought it will be worth it. If anything just block off the gap between the spoiler and the trunk to help keep that pocket of air in place.

Go with the grill block, and wheel covers.