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Old 08-06-2008, 09:01 AM   #1 (permalink)
Master EcoModder
Join Date: Feb 2008
Location: belgium
Posts: 663

vectra a - '95 Opel Vectra GLS
90 day: 37.51 mpg (US)
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wheel dams V2.0 - not so good...

the first mod i did to my vehicle where wheel dams, but i took them off after i installed my undertray.

for lack of better pictures i drew the basic configurations on a picture of a "clean" setup

custom undertray:

original dams... replaced these today:

no real negative feeling in car's response, exept it might cause the breaks to get hot. and they don't actually touch the undertray so teh air deflected sideways might still hit some engine components.

new dalms inspired by VW design, based on the assumption most air would go below them and a lille above.
in reality these where unpleasant to drive, the car didn't coast, and there was more noise, however the later could be a result from connecting the subframe to the car's bumper and allow vibrations to be transmited. if anything positive the car felt a bit more stable in the curves.

after two days driveing it was clear to me these where unlikely to improve FE and i swapped them for the original setup, car emediately drove much more pleasant.

however since the old dams don't extend much beyond the original front dam perhaps a combination of the two might work?

i think the large gap above the new dams where a mistake perhaps they acted as spoilers and renerated some downforce, but i don't think they decreased drag
yet if the opeing above them was sealed that might work...

however the original dams are much smoother, so perhaps i'd better just replace these with slightly extended versions and maje a small opening where i think some breake cooling air would be needed, that would give me peace of mind.
or should i go for something like this:

any thougts on these designs?

aer·o·dy·nam·ics: the science of passing gass

*i can coast for miles and miles and miles*
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