Bumper Coast-Down Test Results
 

Tailpipe fell off and took out the bumper. So I did some coast-down testing before re-installing the spare.

I did two pairs of runs in each direction. The one direction has an extra run as the run in the opposing direction in that pair was interrupted by traffic. This was done on a public road that was fairly flat and straight. Clearly it was not as flat as I hoped since I slowed more in one direction than the other in approximately the same distance.

Test ending in '002' (green lines) was without any bumper. Test ending in '003' (blue [and purple] lines) was with stock uncut bumper. You can note the starting or ending speeds, respectively, in the legend or whatever..

Direction 1 Start:

https://www.miataturbo.net/attachmen...ine=1406467861


Direction 1 Finish:

https://www.miataturbo.net/attachmen...ine=1406467861


Direction 2 Start:

https://www.miataturbo.net/attachmen...ine=1406467861


Direction 2 Finish:

https://www.miataturbo.net/attachmen...ine=1406467861

This is cool. Summerize the results for us?

Looks like, as we knew, no bumper is fastest, but on a ~83mph-35mph coast, what's the time difference?

Coasting down from 78.4 mph in Direction 1, for the given time interval, having no bumper resulted in a .9 mph slower final speed, on average.

Coasting down from 82.0 mph in direction 2, for the given tie interval, having no bumper resulted in a .25 mph faster final speed, on average.

Interpret that how you wish. My opinion is that the presence or cut of the bumper has little to no effect.

Is this NA or NB?
Also, does "no bumper" mean no bumper skin (core still on) or no bumper skin and core?

Come on Moti, you should know better than to bump a thread that's four years old.

OP hasn't posted here in about two years.