Top Speed Runs in S2

[Keeper of The Kitten]

From a purely theoretical point of view - yes, but not much.

It breaks the airflow coming off the tail of the car, it does provide some flat decklid as well which is beneficial. But consider it to be part of the whole shape, not a component in isolation.

What you really have to consider, though, is that significant aero effects are minimal below about 80mph anyway.

Drag is an issue at much lower speeds but frankly making "downforce" (negative lift) is highly unlikely. You can achieve it with massive wings at low speeds, but I mean huge wings - like half the size of the whole car! The sort of thing you'd see on a sprint car. There are autocross cars in the US that run giant wings for low speed competition.

So to sum up, think of the spoiler as just a small part of the whole package. It certainly won't do much on it's own.

[stiglet]

Cheers. I always just assumed it would do very little as the flow would probably seperate off the rear window at any speed where the spoiler would be useful. I'm guessing this is not case?

Sorry for going off topic!

[Keeper of The Kitten]

It might well separate off the rear window - that's something which can potentially be tested with wool tufts taped onto the tailgate at different points, and get someone to observe from the rear seat while driving - maybe get a video camera onto the job!

[Keeper of The Kitten]

Anyone remember the old Cavalier estates?

They were GM "J" cars, I believe the design was Australian

They had a spoiler-like section at the top of the tailgate that allowed air to flow down over the rear window, mainly to keep it cleaner than would otherwise be the case....

....so potentially, something at the upper end of the tailgate could help to keep air attached?

I'm not saying it should be done, it's just food for thought....

Nothing should ever be done without at least conducting some kind of testing!

I doubt we could get strain-gauges bonded into suspension, which would give a nice idea of the loads applied, but as a very rough guide maybe suspension deflection measured by pots could be used instead? It's rough as hell but it would give a feel for changes as speeds increased.

I believe a chap on here might be able to tell us how costly that would be? Data logging has become an awful lot cheaper in recent years for a few channels of data

[stiglet]

I have a bullit cam with a suction mount. Tempted to stick it to the rear window and try this out.

I wonder where i could steal some potentiometers from...

[Keeper of The Kitten]

Start with wool tufts and the camera!

If there is an opportunity to log data with pots it would be great - strain gauging would be even better but I suspect the struts on a road car don't have enough flexibility to get a decent reading from.

[4WheelDrifter]

i must admit that mine felt fine at a speedo registered 175.it doesn't have an undertray.also i've put my tom tom in a few cars and they are all roughly 5 mph faster on the speedo at any given speed.

Speedo registered 175 mph? Nice one.
I challenge anyone with a stock S2 speedo to go faster than that.

[Ross]

Nice one Doug... I must admit, before I stuffed the Coupe I saw it as a potential "project 200" by upping the power and putting an S4 'box in it. It's one of my life goals to drive at 200mph. Always worried about the stability though.

For what it's worth, I maxed the speedo out on the old Coupe when Tom rebuilt the engine. It was running on H&R's and Biltein's, 215/45/17 rubber and no undertray. It was a straight and smooth test-track :mischeif: no wind and crisp 6am air... it actually felt very stable though i would have been nervous about any corners 6600RPM = 165mph so still a good bit wide of the mark! Would have loved to see what was in it with the 430bhp and 7400rpm redline (mihnea was confident it would have made it - i think we figured it to be about 180-185)

Ross

[philS2]

Speedo registered 175 mph? Nice one.
I challenge anyone with a stock S2 speedo to go faster than that.

Must admit,i took my clocks out the other day to chip off the paint around the needle centre,and i spun the speedo needle round by hand and it stopped just short of 175.But it did look like it was 175 when i was doing the speed test(on a local disused runway).I actually moved my head forward a bit to get a good look.So in actual fact i could have broke the 200 barrier and not know it.

[4WheelDrifter]

Must admit,i took my clocks out the other day to chip off the paint around the needle centre,and i spun the speedo needle round by hand and it stopped just short of 175.But it did look like it was 175 when i was doing the speed test(on a local disused runway).I actually moved my head forward a bit to get a good look.So in actual fact i could have broke the 200 barrier and not know it.

I noticed on my runs that the speedo hit the stop at about 174, but the tacho kept climbing. It's a shame if you didn't take note of the revs, you may indeed have cracked 200 without knowing.
Just don't tell the guys with the plasma gauges about the stop.

[wiberg]

The VW Golf mkIV R32 HGP Biturbo has done 323kmh on the test track Nardo.
Should the S2 really have such worse aerodynamics than the Golf?

I know for a fact the the HGP Stage 2a (1bar turbo boost/515hp) will do 310kmh on GPS

[Doug_RS2]

So - My S4 Biturbo - removed wipers, wing mirrors, rear spoiler, used a laser cut number plate instead of no plate. I have added water/methonal injection. Temps were around 24deg C and a head wind this time. The Ruf RT12 did 201 (instead of 212mph). I did 198mph. Videos in the next couple of days. Beat the Mclaren SLR, Diablo VT, the big power Ultimas - lots of nice cars there - i think i was 2nd fastest! Need to finish the S2 and get the nos kit on.

[quattronutter]

good work doug,when are you fitting the nuclear reactor for light speed

[S2central.net]

Big UP to Doug there and the MRC boys with balls of steel... So tantalisingly close to the magic 200mph with the head-wind and what a way to embarrass some exotica on the day - even if you weren't strictly street legal without wipers and such - that is mighty fast - way faster than I'd ever dare.

[Rusty]