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Old 04-04-2010, 01:03 PM   #1 (permalink)
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Clara - '94 Vauxhall Cavalier LS
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worthwhile changes? (spoiler / bumper)

Im slowly getting a grip on the whole aerodynamics basics, although just when something makes sense you bring in other considerations and it all gets very confusing again haha.

Anyhow, looking for basic improvements to the car, Im considering options that came stock, and Id hope youll be able to help say "better!" or "worse!"

First up, rear lip spoiler......

Stock car (actual vehicle)...

EDIT: Better view of rear WITHOUT spoiler

SRi Lip spoiler (hard to find pictures of on the net)

As you can see its very subtle, just a small additional flick and extension outwards. From what Ive read, the Lip Spoiler could well be an improvement?
If it helps I *think* (measured in photoshop) that the rear hatch angle is around 20 degrees

Second up, Front Bumper...



Obviously both would be grille blocked

(I already have a grille block / rear wheel covers / etc planned, these are for future additions, and at present Im just trying to get some form of FE baseline before I get all excited and start modifying )

I know they are not great pictures... but best I can find

Thanks for your input


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Old 04-04-2010, 01:30 PM   #2 (permalink)
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Mirage - '93 Mitsubishi Mirage ES
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I don't know about the spoiler (even if it is in fact functional), but the front bumper looks like it would be an improvement. Not only in aero, but cosmetic.
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Old 04-04-2010, 01:43 PM   #3 (permalink)
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Tank - '96 Ford Aspire 4 door
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If it's an outward extending spoiler, it should help cleanly detach airflow off the rear. The GSi bumper definitely looks smoother, and should help a little aerodynamically and a lot asthetically.
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Old 04-05-2010, 07:47 AM   #4 (permalink)
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vectra a - '95 Opel Vectra GLS
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hi colonelk

nice to see another cavalier/vectra on here.

i've been wondering about the stock lip spoiler too. because unlike other spoilers is extends the trunk. i can see no reason how it might hurt fe, than again i don't think i't will have that big an impact either. the sideskirts might actually have a little function to them as well as they're rather similar to what the calibra had, wich is basically a rebody of this car.

i've done a few mods on my car i'm quite happy with, the best thing to start with is an undertray, and some front wheel dams. both are quite easy to do.

the wheel dams are based on measurements i took on cars that have them, they're just screwed unto the plastic wheel well liner

on thing i found with wheeldams is they really don't work when they're to big... on a lot of cars they seem to be aimed more at deflecting ait away from the area behind the tires than the actual tires, so i just modeled them after real life examples rather than try to cover the whole tire (wich is difficult with this bumper anyway)

the wheeldams are independant from the undertray, but they do prevent dirt that's kicked off the tires to be deposited on the undertray that extends lower than the original wheel well liner

the undertray is made from coroplast, and an aluminum L beam. this is attached with two L brackets to the bumper; than the precut coroplast was attached to this beam with zipties and at the front behind the bumper lip with a few screws trough the plastic of the bumper.

funally at the back two zipties pulled it agains the subframe to make a very solid construction.

the louvres where an experiment, and i sugest leaving them off as i suspect they actually let air in rather than out.

the undertray has the aditional advantage of dampening road noise and keeping dirt out of the engine bay. i'm considdering deleting the lovres and adding some support halfway the subframe to give the tray a more vavorable curve, right now it's smoorh with a dip down at the end, i'd rather have it curve down than go more parallel to the road. i'm also thinking about an extention so that i'll cover the rest of the engine, but i'll do that in aluminum and exhoust and oil sump clearance might make this less straightforward

half of the topgrill was blockd from the factory on my car, as also the lowest row of the bottom grill (this might be standard on all cars, not sure about diesles)

as a resuly any aditional blocking tended to leave the car getting very hot is stop go traffic.

another problem is the airbox takes the air from an area behind the bumper that's fed by the grille, so blocking it off seemed to cause the engine to loose power and FE went down... if you do a partial grillblock, i sugest blocking the side farest away from the airbox.

i'm curently thinking about a (partial) rear undertray, there's some big gaps there especially the transition of the spare wheel tub to the bumper.

the spare wheel well has some rubber plugs that cover (waterdrain?) holes wich would allow things to be attached without drilling.

i've been thinking about rear wheel skirts as well as the car lends ifself to it. but i'm reluctant to drill such a rust prone area.

a setup like the omega/carlton would be cool
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Old 04-05-2010, 05:48 PM   #5 (permalink)
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template thread

I just posted a list of cars with spoilers you might want to take a look at,at the Aerodynamic Streamlining Template thread.
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Old 04-06-2010, 09:01 AM   #6 (permalink)
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Clara - '94 Vauxhall Cavalier LS
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Excellent to see another cavalier/vectra indeed

The Diesel has no grille blocking as standard (I know my old 1.6 petrol had a grille block like yours)

I like the work on yours! I plan to do most of this once I have some form of baseline (ok, after I refill next!)

Rust on my arches is no problem as I have a welder

And thanks to the others for your input

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