Quote:
Originally Posted by arcosine
I sold my 91 CRX HF because it was a California model, 3.25 final drive, and also when I went to bleed the brakes, the fitting broke due to rust. The Saturn is a bigger car, more frontal area. I'll take a peek at the photos.
I cut 6.5 inches off the rear wing, riveted it back together and need to make some brackets to mount it behind the deck.
Looks good... 1991 was a long time ago, I worked for l Douglas Aircraft Company (Mc Donnell Douglas). I had a 1977 honda accord with a 1981 1355cc civic cvcc engine milled to 10.25:1 compression ratio, advanced ignition timing, jetted lean and a taller fifth gear. I got 50 mpg consistently without hypermilling. It would have done better with some aeromods! It finally burnt a piston.
Lets see... If I assume that your CRX top speed was 100 mph and had a 7 mph increase with the tail, then the reduction in drag would be 1-(100/107)^3 =22%, pretty good.
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*The 1st-gen CRX 1.3-liter was rated by Honda @ Cd 0.32 and 18.5 ft-sq frontal area.Hucho ran it in VW's tunnel and reported Cd 0.35,for a drag factor of 6.475 ft-sq.It's top speed was 93 mph and returned 52 mpg at 55-mph (naked).
*By 1990,with the 'kit',and cardboard and duct tape mods made at 4,420' Bonneville
she ran 97.6 mph,up from 89 and change 'stripped.' When I left the Salt Flats,her mileage was up into the low 60s.
*I never could get her out of 3rd gear,so Hucho's CdA/top speed relationship doesn't help much.
*From the increase in mpg,I could use GM's mpg/CdA relationship to reverse-engineer the Cd,at 0.235 and CdA= 4.347 ft-sq which was confirmed over the phone in conversation with GM's Aero Lab personnel.
*At Chrysler Proving Grounds,one of Car and Driver's road warriors saw 98 mph @ 52-degrees F.
* Coastdown tests showed Road Horsepower to be 8.55 hp@ 50 mph,and 19.5 hp @ 70 mph.
*At nearer standard temp and pressure,she's run an even 100 mph.
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I have data for the 1991 Saturn SC and they report a Length/Height= 3.474,Cd 0.32,and Af= 20.1 ft-sq,for a CdA= 6.432 ft-sq,(a little better than the stock CRX).
*The front of the SC is great even by today's standards.Your airdam mods will correct the flow going under,so she'll be 'fully upgraded.'
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*1st-gen Insight is Cd 0.25 @ L/H= 2.854 (more like a K-form roof and nice body plan taper)
*Your CRX was Cd 0.29 @ L/H= 2.956 (roof is great but doesn't get the extra kick of plan taper).
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I think that the SC will respond really well to the tail mods.If you run a little longer tail than I did,even with the larger frontal area her CdA should come in below 5-ft-sq,easy!
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I would have liked your Accord.My mom had an automatic trans version and I could never coax more than 36 mpg out of it in straight hwy driving.