Flat Floor Tray

[craig_mr2_mk1]

I'm thinking of making a flat floor tray for the bottom of my MK2 Turbo. Has anyone done it and what material did you make the floor tray out of?
Did you cut out the floor below the engine or drill big round holes or just leave it covered? All info would be helpfull & any pics would be nice too.

Thanks,
Craig.

[bri0905]

I haven't done it but have been thinking about it.

I think there would need to be some louvres or vents feeding air up into the engine bay. As far as i'm aware the standard design pushes air up from the ground over the engine and out the engine lid.

If it's for a track car this would probably be more important to keep temps low.

[craig_mr2_mk1]

Yea this is for a track car/Sprint car. Been thinking about doing it for a while but haven't got round to it yet.......

[jasongtr]

i know nothing about this but i would guess you would need to be careful as you are messing around with airflow under your car, perhaps if you get it wrong you will induce lift, just because it works on a race car doenst mean it will work on an mr2 without any other aerodynamic mods

but like i said im clueless just pointing out a potential problem that you may not of considered

[Shmed]

I'm thinking about this too. I was thinking a fairly thin sheet of aluminium would be best, light, rust resistant and fairly easy to work - not that strong, but you don't really want to be grounding it anyway.

Things I thought might be of concern are:

1. What Jason said
2. What bri0905 said
3. Airflow into the Chargecooler/engine rad
4. Strength of the mounting points - I would use the holes thatthe plastic undertrays use

[Shmed]

With respect to no.3, I was thinking of channelling air through the bumper (big opening at the bottom) past the rads and into the frunk, then getting a Border type bonnet and pushing the air out that. Obviously there'd need to be some frunk mod too to stop it 'vortexing' if that is the right terminology (I might give Ross Brawn a call )

[monkeyra]

There is a long thread about this on one of the USA mr2 boards in their aerodynamics section. Worth a read, and someone on there has all the dimensions needed.
Something I've also been meaning to do!

[craig_mr2_mk1]

Do you have a link to the American tread as I dont use there forums at all.
Cheers,
Craig.

[Shmed]

You won't be able to view unless you're a member mate. Takes a few days for them to authorise your account too.

[matt.m]

Rogue designed and fitted a flat underside for a mk2 super GT car ....give Patrick or Matt a call.
The rather nice 2.2L Turbo black and orange car featured on the Super GT thread:



Hope it helps.
have fun
Matt
www.teamresinexracing.com

[monkeyra]

Loads of threads on MR2oc.com :

http://www.mr2oc.com/showthread.php?t=331965

http://www.mr2oc.com/showthread.php?t=372651

http://www.mr2oc.com/showthread.php?t=300276

http://www.mr2oc.com/showthread.php?t=277999

[Century Motorsport]

I'm pretty sure you can buy the cad drawings off someone in america. It'll be in the american OC.

IIRC they stopped at the engine bay though which isn't ideal... to make it right you need to have a full floor with a couple of decent tunnels to make some proper aero.

Make sure the floor is billiard table flat, no dents or undulations and get the car as low to the ground as possible ... that should see you some decent performance gains!

[pbmr2]

i'm doing a similar thing to my mk2, got a mate who is a fluid dynamics expert designing it all for me.. because i'm a simpleton when it gets to the heavy aero stuff

at the rear the diffuser needs to expand the air by as much as possible without seperating the flow.. i'm changing the front bumper shape so the whole underside of the car basicly becomes a long venturi. for this i'm adding skirts (not the styling kind) of rubber to futher control the pressure under the car. we've found that anything more than double the expansion tends to give flow seperation. again it's all down to the venturi calculations.

to try and further clean up the under body flow, i'm dividing the airflow from round the wheels away from the under chassis air. most of the front wheel air pressure will leave via a wing vent, with a gurney at the front. however due to brake ducting much venting is still needed.
the air (under side) is then reused as intake for the rear brakes. rear arches are vented directly backwards, seperated from the under chassis flow. using a large hole cut through the chassis and rear bumper.

he's using autocad to do the drawings so i'm sure i can get a copy of them and post them up if you like. not got anything on the car yet as it's still in the strip down stage.
i'm hoping to have the first draft of the aero on the car around June.

we're planning on using 3mm(ish) plastic sheeting. as it's hard wearing, won't deform from impact and it's easy to work. also comes in big enough sheets that a single piece can be used..

the underside is only one of the 6 sides you need to worry about though.

[Century Motorsport]

[tonigmr2]

Gartrac racing did one for the front half of my MK1...out of aluminium. Haven't had a chance to test it yet...

[dantheman]

ive given this a lot of research and thought. it depends on whether you are just trying to reduce drag or if you actually want to generate downforce. for drag purposes anything flatter than the standard undertrays will be good. for downforce you really have to completely remodel the airflow around the car. compare the mr2 with any modern lotus and you will see what i mean.

1) rad airflow must go through the frunk and over the windscreen
2) large and low front splitter
3) air from the front bumper should be fed to the wheels for brake cooling. mudflaps and turning veins are required to stop turbulent arch air from going underneath the vehicle
4) sideskirts that go as low as you dare
5) engine bay airflow cannot be affected. minimum requirement is a mini diffuser at the front edge of the engine bay. an underbay scoop is even better. engine lid fans would be best of all. the more air you can suck out through the engine bay the more effective the rear end aero will be
6) you must negotiate the sump, rear subframe and exhaust without sharp turns or step changes. this is by far the hardest part. there is no point in having a rear diffuser if the air that is fed to it is turbulent.
7) rear diffuser should be long and shallow, about 7 to 10 degrees. with diffusers like this less is more, otherwise flow just wont stay attached.
8 ) if you can manage to get flow tunnels and venturi structures involved, with successfull use of strakes and vortex generators you have done well.

bear in mind changing the airflow around the vehicle will affect the handling, far more significantly at high speed than low speed. A change like this must be considered within the bigger picture of your whole tuning package.