Spoilers

SuperRedMR2 · Post by **SuperRedMR2** » Fri Jul 17, 2009 8:35 pm

I know Toyota must have spent millions of £ developing the rear spoiler on our wicked motors, but has anyone fitted any other rear spoilers to them before?

Pictures please

LimeyMk1 · Post by **LimeyMk1** » Fri Jul 17, 2009 11:24 pm

MartG · Post by **MartG** » Sat Jul 18, 2009 12:30 am

Do a Google search for 'Plumley spoiler' - basically it's the standard spoiler moved rearwards where it receives more airflow - I have one as well as the 'chav' spoiler in my avatar pic

Tiny · Post by **Tiny** » Sat Jul 18, 2009 12:32 am

An evo rear spoiler with 20mm cut out the end some will call blasphemous but Crazylegs and i trial fitted one and it did look disturbingly good. square enough to fit in with the car but modern enough to really set it off.

coanda · Post by **coanda** » Sat Jul 18, 2009 12:37 pm

I'd love to see a pic of that on the car - I guess you'd have posted it if you had one?

I do wonder if anyones ever tried a fastback on their cars. It seems to me that the rear deck is really just generating drag and the rear spoiler doesn't do a great deal (toyota adding the roof clear extension just adds to my suspicions). I've been watching rain on the spoiler just recently and it really doesn't clear very quickly suggesting the airflow isn't very quick or laminar back there. This seems to fit with some results they put in racecar engineering mag just recently where they put a fastback on a noble, which has a similar rear deck......

MartG · Post by **MartG** » Sat Jul 18, 2009 1:14 pm

If you are inetersted in Mk1 airflow, have a read of this thread and the one it links to on www.mr2oc.com - they discuss some cfd analysis that has been done on the mk1

http://forums.twobrutal.com/showthread. ... t=analysis

coanda · Post by **coanda** » Sat Jul 18, 2009 2:01 pm

oooooo thanks! time for geek mode!

edit:
awww...another forum I need to sign up to...maybe later...to save the bother, did they get any believable results?

MartG · Post by **MartG** » Sat Jul 18, 2009 2:25 pm

coanda wrote:
awww...another forum I need to sign up to...maybe later...to save the bother, did they get any believable results?

Yes - some very interesting results, especially in the area of the rear spoiler and the bonnet ( vented bonnets are worth looking at )

mlhs · Post by **mlhs** » Sat Jul 18, 2009 5:13 pm

I recently done my dissertation on the aerodynamics of a MK1, concentrating on the spoiler looking at downforce. As many know the standard design has no or very little aerodynamic effect due to the design above the engine lid, and is basically for aesthetics. I researched and designed a few different spoiler designs and ran it through CFD analysis. The 'chav' type spoiler, although looks ridiculous was one of the better spoilers, generating a substantial amount of downforce. I am hoping to go into aerodynamics, F1 is my goal. If i get a copy of the software i was using im going to start a few little projects for my MK1.

cartledge_uk · Post by **cartledge_uk** » Sat Jul 18, 2009 5:16 pm

Tiny wrote:An evo rear spoiler with 20mm cut out the end some will call blasphemous but Crazylegs and i trial fitted one and it did look disturbingly good. square enough to fit in with the car but modern enough to really set it off.

Been done in the states and aus quite a few times, I have an evo spoiler in the garage I was going to use (been there over a year), I think mk1 chris is having it though

treyz32 · Post by **treyz32** » Sat Jul 18, 2009 5:24 pm

I do wonder if anyones ever tried a fastback on their cars.

It could be done, extend the c piller and taper inwards to the rear of the car. Not sure how it would improve airflow or if it would hinder cooling.

Heres a mock up:

MartG · Post by **MartG** » Sat Jul 18, 2009 6:08 pm

mlhs wrote:The 'chav' type spoiler, although looks ridiculous was one of the better spoilers, generating a substantial amount of downforce. I am hoping to go into aerodynamics, F1 is my goal. If i get a copy of the software i was using im going to start a few little projects for my MK1.

Given the Mk1's tendency for the front end to get a little light at speed ( something I've noticed myself on track ) I'm a little wary of running with my 'chav type' rear spoiler without doing something about the front-end lift first. I've already made a 'papal' type bonnet, with a vent which discharges into the low pressure area identified in the cfd plot, and I'm also thinking of fitting a front horizontal splitter to try and take advantage of the high pressure area around the nose

Tiny · Post by **Tiny** » Sat Jul 18, 2009 6:40 pm

coanda wrote:I'd love to see a pic of that on the car - I guess you'd have posted it if you had one?

His mrs' boy had bought it to be fitted to his BMW 525i..........yeah dont ask.

My car was in for work at his and just looking at it i thought put it on the back of the car and just thought it looked really good nd yet so wrong but reallly right at the same time.

didnt think to take a photo.

mlhs · Post by **mlhs** » Sat Jul 18, 2009 9:43 pm

Treyz32: I made a CAD model in Pro E, with a similar type cover over the engine. However from the results i got it actually increase lift as apposed to negative lift or downforce. Surprising, i didn't really have much time to spend on developing the design to see if i could add vortex generators to help aid the slow onto the spoiler.

MartG: If i get the chance a front splitter would definately be something id try and put together. Relatively simple things to make, just depends on design and what you make it out of. I remember reading a little while ago of a member on s2ki making a front splitter out of mdf or similar and bolting it to the front bumper of his s2000. He reported that it increased the handling capabilities and the theory behind a splitter is very simple.

A book i used and referenced quite a lot in my dissertation was Competition Car Aerodynamics, was really helpful;

http://www.haynes.co.uk/webapp/wcs/stor ... &langId=-1

coanda · Post by **coanda** » Sat Jul 18, 2009 10:13 pm

mlhs:

any chance of a pdf of your dissertation?

I would expect the fastback to clean up the air over the engine cover, stopping it from going turbulent, it will also create differences in cornering. I can see that there could be extra lift from this, but I also wondered if it would cut down on drag a little. I need to re-read that noble article. Aircraft are my thing and I'm just starting to seriously get into cars so my reasoning on stuff could be a bit ar$e-about-face!

mlhs · Post by **mlhs** » Sat Jul 18, 2009 10:23 pm

Hey Coanda, I don't have my dissertation on my laptop sorry. Im on holiday atm and wont be back till mid to late october, maybe later.

As i mentioned i only ran the CAD model through CFD once with the astback design. As you mentioned it did reduce drag, but to me surprisingly added lift, as i thought that keeping the flow laminar over the car and onto the spoiler would generate more negative lift.

I may have some pics of before and after lying around on my laptop ill see if i can find them tomoz its a bit late, also the CAD model i used was simplified, because the CFD software i used couldnt cope with a fully detailed CAD model.

MartG · Post by **MartG** » Sun Jul 19, 2009 10:09 am

mlhs wrote:MartG: If i get the chance a front splitter would definately be something id try and put together. Relatively simple things to make, just depends on design and what you make it out of. I remember reading a little while ago of a member on s2ki making a front splitter out of mdf or similar and bolting it to the front bumper of his s2000. He reported that it increased the handling capabilities and the theory behind a splitter is very simple.

A book i used and referenced quite a lot in my dissertation was Competition Car Aerodynamics, was really helpful;

http://www.haynes.co.uk/webapp/wcs/stor ... &langId=-1

Yep - got that book a couple of years ago

When I was talking to my son about making a front splitter, he asked if I would be making it out of carbon fibre - I told him cf was too expensive especially given that a splitter is prone to damage, but that I would use a cheaper carbon based composite material called plywood

greglebon · Post by **greglebon** » Sun Jul 19, 2009 2:46 pm

Having read some of the related stuff from the States in the links, I feel I must make a point...

The Mk1 rear spoiler IS functional: it improves the cars stability in cross-winds....its not JUST for aesthetics...!

The Mk1 has a cd of 0.36, for info.
The Mk2 is around 20% better than this.....

Also, the front end lift was almost neutralised by the addition of the front lip on the Mk1: the early cars suffered from front-end lift at speed...!
A small splitter will greatly increase the front aerodynamics; go for it Mart!

I ripped my OEM spoiler off and replaced it with an adjustable CF one: the CF does have a positive effect at speed...I didn't test it for crosswind effects, mind you (I suspect a detrimental effect!

)

IMHO, it suits the car really well....?

mlhs · Post by **mlhs** » Sun Jul 19, 2009 6:57 pm

greglebon: I only simulated front to rear air flow 'The Mk1 rear spoiler IS functional: it improves the cars stability in cross-winds....its not JUST for aesthetics...!' obviously i didnt state that earlier, however im sure the spoiler adds some stability during cross winds.

I have a program my supervisor gave to me that he designed that calculates any car's coefficient of drag.

Simple test, but i found there wasn't anywhere i coul safely carry out the test in the time i had. ( probably best off uing an airstrip etc) Basically find a long level straight road, drive at 70 mph and pop the car into neutral, as soon as you put the car into neutral start a stop watch, and make a note of the time it takes to get to 60 mph, 50, 40 etc until you are stationary. Then you enter the results into his program and it calculates the results.

Would be interesting to see if it did give 0.36 cd.

Swiss Toni · Post by **Swiss Toni** » Sun Jul 19, 2009 7:57 pm

Not the most dramatic, but I do have one with a high level brakelight in it.... $\:D/$

www.imoc.co.uk/forums/garage.php?mode=v ... e_id=13193.

www.imoc.co.uk

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