AdamR28

As above, its normal. Haven't heard anyone else mention it recently so assume people just get used to it.

Yeah those are just plain old bunny hops.

I hope you just gave him three quarters of it?

Well worth reading, in that case: https://www.waterstones.com/book/the-chimp-paradox/prof-steve-peters/9780091935580

Awesome stuff gents, look forward to the videos! In semi-related news, took my daily to a sprint event at Cadwell this weekend, which was brilliant fun. A different setup to normal - with 2 different layouts, cumulative scores for the 6 runs rather than 'best run counts', and penalties for hitting cones / falling off the track. A bit like a rally, really. Despite some much more potent and non-standard machinery, including one guy who considered his ITB'd-standalone-ECU'd-Ohlins-dampered-Enkei-RPF1-wheeled-bucketed-and-harnessed MX-5 to be 'standard', I ended up 4th (of 17) in 'Standard' class. The night runs using 90s Japanese candles were... 'interesting'. Not had the adrenaline shakes for a LONG time, but on Sunday that buzz was back Thanks a lot for your aero input Dave, great to have some known reliable info! I have a few bits and bobs to play with before my next track day now. From what I can gather Rowan, skirts are banned in F1 after issues with them sticking meant instant and huge drops in downforce at critical times. There are also strict rules regarding sizes / positions of other aero devices, so they have to use the wings to try and claw some of the gains back. Here's a good little video: From what I can gather there will be even stricter reductions in wing downforce for 2022, which will be balanced out by more allowance for ground effects - which will leave air coming off the back of the cars with reduced wake.

Well, the aerofoil thing flapped about like buggery so I ripped it off, and the steering wheel nearly fell off, but other than that... The aero works - surprisingly well. The car has natural understeer at low speeds (really obvious on the sighting laps), yet wants to swap ends at high speeds. It's also pretty fast in a straight line. It also appears my engine is a 2 stroke, as it burns oil and fuel in a 1:40 ratio. But who cares, it's a lot of fun! Upgrades planned: Mainly working the rear floor to sort the high speed balance. Found a great article (which I am guessing you had a hand in Dave? @monkeyseemonkeydo ) to help figure out the relevant geometries for a functional diffuser: https://www.racetechmag.com/2017/08/willem-toet-explains-motorsport-diffusers/ Obviously a car with marshmallow-like suspension is never going to have optimal aero, but if I can get the car balanced - even by reducing front downforce / adding some lift back in - that'll do nicely.

Nice solution! Do you have a link to the parts used?

And some stupid aero bits from this morning... By my reckoning, just this will be enough to improve the top speed of the car by 3mph!

I'd like to see this one. Not sure how to call it though, either way whoever goes in that car it'll be interesting!

Papers in the post Seriously though thanks for the heads up and link to that article, some good stuff on Speedhunters. I've not looked there before as I've not been bothered with making the car look like it crashed through a branch of Halfords, but will do going forward. The car is actually pretty much ready for the first outing now which is Saturday all being well, and I did vent out the bonnet just not as extreme as some solutions! The rad is left as standard but ducted in and out, so I'm hoping that will reduce drag a fair chunk. A few pics... Now pretty much bang on 750kg, which will do me. Gut feel is that I'm going to need a rear wing to balance things out, but we'll see... Maybe I'll try and go full McLaren Elva sometime No wind in the face at 70mph, apparently!

Nope! Appreciate it is confusing, but thousands of bikes prove it works...

Already seen that first hand. Borderline dangerous IMO. The video... felt forced. Normally his vids make me want to ride, this one made me dislike ebikes a bit more.

Yeah, you do flip it around - the removal tabs face the BB

Thanks for calling and emailing Pablo, glad we have it cleared up for you already.

I think that adaptor you have Leon is one that comes with BB7 brakes.

I reckon you could make a good 5% improvement, perhaps at the expense of aesthetics though - have a look at EcoModders forum for ideas!

Found another paper that agrees with the one Dave posted above, not the same results exactly but a general significant decrease in drag from fitting the tabs / deflectors / whatever: http://publications.lib.chalmers.se/records/fulltext/250512/250512.pdf (page 18 onwards). Note this study uses seemingly less wide tabs, and only fitted to the front. I think I'll shoot for about 40mm, spanning the width of the tyres, fitted front and rear. That brings me to another question... the wheel arch pressure plots in the paper above, after adding the wheel tabs, seem to suggest the pressure above the wing is much higher than below it. In which case, would running vents at the top of the wing have the opposite effect and allow air to enter the wheel arch area? Or would louvres / Gurneys sort this out? Appreciate it is a case by case basis but just thinking out loud... Rowan, I've seen some stuff on enclosed wheels / solid hub caps in my link above, plus this vid below. In short it can help drag but at the expense of brake cooling:

This. When calipers break it is almost invariably one or more of the following: - Random bolts / washers setup - Bolts not kept tight - Adaptor breaks first and takes the caliper out too

Thanks again Dave! Yeah what I was meaning is that the MR2 seems different to most, maybe because of the low nose. A picture will tell it better than my words (the car in the photo has a body kit with a slightly extended 'nose' but not too much)... Having compared the vent locations on the VX220 and Elise - the closest cars I could find in terms of nose height - they seem to be quite far back, much more so than the pressure plot from a 'normal' car would suggest. Been trying to work out some CFD software for myself the last few days but not having much lock with OpenFoam or any of the free CAD stuff. Perhaps it's a step too far and will just swallow too much time anyway! The handling as standard is moderate understeer at low speeds and a bit 'agile' at higher speeds. Apparently with the roof on and no spoiler, the rear creates a fair amount of lift (looks like it from the above image too). Obviously this will all change now so I'll have to suck it and see. Hoping the balance will be better having blocked the nose off, ducted it out, and removed the roof! I can tune handling fairly easily with alignment though. The rear has mild toe out in bump, so running either slight toe in or parallel will give quite different characteristics!

That's all brilliant info Dave, and pretty much what my research turned up just with a few extra nuggets - thanks a lot, really appreciate your input! The idea behind venting out of the bonnet is to get rid of the air that otherwise would be flying around behind the rad, yeah. I've already found some CFD images from the MR2 and surprisingly most of the bonnet is in negative pressure (I think it's because the 'line' between the bumper and bonnet is quite low compared with a 'normal' car, which seems to have a region of extreme negative pressure right at the front of the bonnet, then transitions to high positive pressure at the base of the windscreen?), so had carte blanche with the vent location. Cut that the other day (and left a Gurney at the front), just needs the ducting finishing now in the style you said. With the car being rear engine, and just having a few long alloy pipes running from back to front in a small tunnel, there's not too much heat going on so I figure I can seal the floor pretty effectively. To my untrained eye it doesn't look too bad as standard (for an older car), certainly better than a FWD car with no undertrays and an exhaust that runs all the way back, but can defo be improved. There are various 'features' with handy holes already in adequate positions for popping some rivnuts in, so that's the route I'll go. Looking from the front... appears my car is missing those deflectors / diffusers in front of the front wheels! And from the back: The lowest part of my exhaust sits pretty much level with the bottom of the sump, so I'm not sure how much room there is to fit a diffuser. Have chopped a ton out of the rear bumper instead, while still leaving just enough to make it look car-ish That image is a pretty spectacular demonstration! I had intended to just add a pointy 'tail' to the rear of the roll bar, a bit like the bottom right of the below pic. The tubing is 50mm diameter so with a 100-125mm tail I figure that will reduce wake significantly and should at least halve the drag from the roll cage. And look pretty bloody weird in the process = win. Any thoughts / data on completely enclosing the rear wheels, aka the early Honda Insight? From Ecomodders forum I can see it will drop some drag, but I am wondering if I might run borderline on brake temps if I do that - the car is about 63% rear weighted and the rear brakes carry out a high proportion of the braking! Perhaps just stick with wheel tabs, plus try to a.) keep air out of the arch, and b.) vent the tops like on the front?

Thanks for liking Rowan's post Dave, thats a good clue! From what I can tell, pretty much in this order... I'm more thinking about drag than lift / downforce, for now anyway. - Block off excess holes in the front bumper. - Vent out of the bonnet. - Flat floor. - Diffuser makes a small difference, better if the air gets to it in good 'condition', I won't bother for now. - Vent out from wheel arches. - Deflect air away from the front lower faces of the tyres. - May even add some streamlining (bits of plastic gaffer taped into an aerofoil shape) to the roll bar. The MSA rule book specifically states you're not allowed to do this for competition, so that means it must do something if you do! There's a reasonable amount of CdA going on there (not far off 10% of the total drag of the car, from my maths!) so if I can halve it that'll be a nice easy gain. But who knows what I'll end up doing

Hadn't seen these - but I have now - thanks dude! What's 'comforting' is that the theories all the YouTube Experts™ talk about align, hopefully meaning they're not bullshit, ha.

1ZZ and staying that way. Put waaaayyy too much time and effort into that manifold to swap now At the moment I'm not sure, perhaps 730kg ish, then likely 750+ once I've added aero bits n bobs.

I wanted to leave it body-less, but then checked some more TDO's T&Cs more carefully and I think it'll be borderline, and not worth the hassle. So the regular bodywork is back on and I've spent the last few days in a YouTube 'race car aerodynamics' black hole, mostly in the hands of Kyle.Engineers, who used to be at Merc F1 apparently: https://www.youtube.com/channel/UCh3tzzP6n5b1EWcMUpiEhXg. Aero is something I've never really bothered with before so it's nice to learn something new! I figure even though the car will be heavier, it will still be ugly as hell and overall faster than no bodywork. How much left to do on the TT Luke? What sort of spec is that engine that's going in? Looks like it'll be fun for some road blasting! Good call on the tyres Sam, far too many people stick 888s or similar on kit cars for the road, then wonder why their cars are scary in the cold and damp And because this thread still needs things to look at (this is obviously pre bodywork fitting)...