How do you get any aero downforce/less lift out of a ST185?

[OnAll-FOUR]

Most people here know alot about the engines on our Toyotas, but I'm looking for ideas on aero improvements to celica st185s.

There are plenty of kits on the web for later model celicas but the 185s have limited options.

A big GT wing would proably help but I still haven't seen one that looks like it belongs on the car. Another option would be a supra style high rear wing.

What about the front? canards? front air splitter? what would I need to do to get the most out of them?

I was thinking of maybe making some baffels in behind the front bar to help direct some airflow through the front heat exchanger for the intercooler. Would i get any areo benefit if included some wing elelments similar to below.



Maybe I'm just better off going for a rediculously wide body and fat tyres

[oldcorollas]

if you are going 150-200km/hr, then perhaps you can add something...
however the effect of the device, compared to the weight of the car, may prove to be fairly insignificant. and the time you need it most, cornering, it will likely have little or no effect.

as for the ducting, it should be sealed to not let any air around the radiator/exchanger anyway..

if you dropped it to like 50mm clearance, then splitter etc will have more effect, but ..

are you trying to get more corner grip? (what speed for cornering?) more straight line stability?

[2jzhilux]

try a big flat sheet of aluminium covering the whole underneath of your car
you want the air underneath to have as little resistance as possible so the car is sucked to the ground*











*disclaimer this may or may not work under 200kph

[OnAll-FOUR]

You guys are probably right about the whole speed thing. if i was just doing hill climbs and low speed events then wight would be more of an issue.

However what about a super sprint or track days at eastern creek or Wakefield? the car has a quoted top speed of 240kph. I'm not sure how close I would get to that in current trim, but with a little more power?

[Roundy]

a lot more power

i hit 170ish on the Wakefield straight, from what i have seen Justen hits ~240ish i think

the big thing i would look for with aero mods is to reduce drag, the reduction in lift is going to be minimal because on a street car you just can't manage the air-flow well enough (particularly under the car)

ducting/guiding the air into the radiators is a good start to improve their efficiency, have a look at the GT8 and see what Juestn did with the IC

as for what Ecotechilux said, the issue is more the ground clearance, for an underbody to work it can't get any more air from the sides of the car, which is where the low ride height and side-skirts come into it, however from what i have read, Cannards on the front end also help this cause by generatin vortices that help prevent air going under the car, and also reduce drag somewhat by keeping air out of the wheel wells...but at road speeds the improvement would be minimal

also any rear wing needs to be above the roof line of the car to work properly

Cheers
Nathan

[Rcubed]

turn it upside down?
oops sorry, i thought you said aesthetic improvements

[AndyTTR]

The concept with the flat underbody is to maximise the velocity of airflow under the car compared to the velocity of the air stream flowing over the car. The net effect is like a giant upside down wing - the difference in velocity causes a pressure difference, low under the car and high on top. The result is downforce.

Adding an underbody diffuser might not give you sigificantly more downforce on a road car, but it should reduce your drag and increase stability. I remember reading somewhere that the IS200 / 300 has a near flat surface underneath for this reason.

[celicapain]

most of the downforce on any serious race car comes from the underside of the car.
flat bottoms, diffusers and bees dick ground clearance all help you keep pressure/turbulance away from the underside of your car and let any air pressure on top generate downforce.
however you dont get very much aero assitance under 150km,/hr so there is little point doing anything like this to a road car, only on a circuit racer.
if you really serious about being able to drive upside down you should have a look at ground effects. they used to use this in formula one but banned it because it made the cars unpredictable. The idea was to use a suspended skirt on either side of the car to touch the road at all times creating a sealed tunnel underneath the car, allowing mind blowing downforce to be generated with minimal drag. some of the cars had more complex suspension systems for the skirts than they had for the wheels!

[Roundy]

they used to use this in formula one but banned it because it made the cars unpredictable. The idea was to use a suspended skirt on either side of the car to touch the road at all times creating a sealed tunnel underneath the car, allowing mind blowing downforce to be generated with minimal drag. some of the cars had more complex suspension systems for the skirts than they had for the wheels!

it didn't directly make the cars unpredictable...but if they hit a bump it could (and would) lose all ground effect downforce, net result, massive loss of grip quickly followed by a horrific crash

but ground effects are 100% irrelevant for a street car

[celicapain]

thats what i meant by unpredictable-going from planted to seriously planted.
and ya, ground effects like most aero doesnt work on the street, cept for reducing drag/increasing fuel economy.

[celicapain]

or you could just do this

[Roundy]

thats what i meant by unpredictable-going from planted to seriously planted.
and ya, ground effects like most aero doesnt work on the street, cept for reducing drag/increasing fuel economy.

that is mostly what i would look for...except it will reduce lift somewhat...but it won't be a lot, might notice it at eastern creek around turn 1 possibly

[Moppitt]

are you trying to get more corner grip? (what speed for cornering?) more straight line stability?

Would there be differences in the design of the underbody if we are going for one rather than the other? or are you refering to other easier ways to achieve the same ends?

I have heard it reported that undertrays do cut down on the road noise a lot as well, i think thats from reduced turbulance and having another layer between you and the tyre noise ect.

Looking at the underbody of all the new BMW's they all have some serious work put into the underbody trays ect, teh new e90 has almost flat (except for what only looks like channels for the air to flow... and a gap for the exhaust, but even that is pretty small) underbody all the way back to the rear axle.

[celicapain]

have you had a look at vortex generators? ive heard that they can make a difference and they are easy to fit. you just gotta get some of the big ones which actually do something.

[Sam_Q]

edger at autospeed has managed to get some decent downforce while playing with front difusers on one of his cars