THE ROVER SD1 FORUM

Punx0r · SD1 Regular Joined: 05 Nov 2006 Posts: 252

Can anyone kindly relieve me from my ignorance and tell me how many different types of rear spoiler there was for the SD1? I assumed there was only one type and I think I've dropped a clanger by buying the wrong one for my vitesse! Rolling Eyes

Anthony

ramon alban · Posted: Fri Nov 23, 2007 12:15 am Post subject: Re: Rear spoilers

Punx0r wrote:

Can anyone kindly relieve me from my ignorance and tell me how many different types of rear spoiler there was for the SD1? I assumed there was only one type and I think I've dropped a clanger by buying the wrong one for my vitesse!

Anthony, The original rubberised factory spoiler was fitted only to the Vitesse and is characterised by a little bit of "give" when pressing it with your thumb.

It has eight fixing studs on the underside and is no longer available new.

I believe there was an aftermarket "lookalike" rear spoiler made from fibre glass, hard to touch - dont know about fixings or availability. Check with Rimmers!

For perceived benefits and alternative/other viewpoints see

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Ramon

chris_derby · Posted: Fri Nov 23, 2007 2:56 am Post subject:

My old 2600 VDP had what appeared to be a Vauxhall spoiler on the tailgate, but Inever bothered taking it off as it looked really cool!!

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Auto Vitesse, gonna be a beast!

Lehto · Posted: Fri Nov 23, 2007 6:07 pm Post subject:

You propably ended up with a cosworth style spoiler Laughing

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Owner of 3 Rovers and 1 MG.

chris_derby · Posted: Fri Nov 23, 2007 7:03 pm Post subject:

Cosworth style? The spoiler on my 2600 had GM stamped on it, & I had one that looked exactly the same on my Cavalier...

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Auto Vitesse, gonna be a beast!

Punx0r · SD1 Regular Joined: 05 Nov 2006 Posts: 252

I shall have to take a photo of it next the the one on the car for you guys to see. It's the same sort of rubber, similar finish, but has four threaded holes on the underside and adhesive tape instead of studs. It's also a fair bit smaller.

The seller on ebay seemed quite confident that it was an SD1 spoiler.

And Royal Mail bent it in the post...

Rimmers do list a fibreglass rear spoiler on their website Smile

ramon alban · Posted: Sat Nov 24, 2007 11:52 pm Post subject:

5000SE wrote:

A rear spoiler creates downforce at the cost of drag (afraid I have to take issue with Ramon's article that the spoiler reduces drag - sorry Ramon but that's like saying holding up a board from the sunroof will reduce drag, because the spoiler increases the height of the 'slab' back end of the car, and it's the negative pressure area behind the car that causes more problems than the positive pressure in front of it (hence why NASCAR drivers tailgate, and why aeropanes are pointy at the back end).

The combination of lower ride height, front chin spiler and rear spoiler make a significant difference to the way the SD1 is planted to the road.
The reduced drag comes from the lower ride height (reduces the amount of air getting into the wheelarches and airflow under the car where drag is horrendous)and front spoiler, either deep chin or the standard S2 version (both of which reduce the air going under the car).

Hi Lawson, I'm coming around to your technical arguments hence my comment earlier in this thread of "perceived benefits and alternative/other viewpoints" which have been appended to my original essay in the interests of balancing the discussion.

If I may, I will add your alternative views/conclusions also?

But then, going over the original anecdotal evidence to which I had quite close contact, there still does not appear to be an explanation (not to include placebo Confused

) to rebut what happened to the car/person who told me of his experiences.

As additional comment to the overall subject that has been rumbling along, I had this cute idea for an experiment!

When summer comes and my TP comes out of storage, (as an alternative to removing my spoiler) I conceive it to be possible to strap an MDF board, from the top of the tail gate to the high point on the rear spoiler, to prevent the downforce generated by the spoiler itself.

If the alternative viewpoints are correct the MPG measured by trip computer over, say, a couple of miles should increase because of reduced drag compared with the anecdotal supposition (spoiler exposed) over the same track in the same conditions.

None of the above experiment would emulate the original SD1 shape of course, but it would be fun to find out.

On the other hand perhaps someone who is about to fit a factory spoiler might care to do some before and after measurements?

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Ramon