Can of paint and she'll look lovely 

It looks like a life size Lego Technic car

Quote from: Joesson on November  7, 2020, 13:41PS. 10/10 for ugly, you've got that nailed no adjustment necessary!

That made me laugh quite a lot. Ha. Thanks.


@Petrus , at the moment I have Tein lowering springs with 1 coil cut off the front and 3/4 of a coil cut off the rear. As standard they have the first one and a bit coils completely coilbound, so I figured this is a) safe and b) doesn't affect the spring rate much, if at all.

Ride height, to the lowest part of the pinch weld on the sill, has ended up 130 rear and just over 130 front - that's with the 25mm smaller than standard radius tyres, so working all that back it is about 5mm higher than standard despite the lowering springs!

As for handling balance, I can cope with understeer at low speeds as it allows you to trail brake more, but I really cannot deal with the front end not going where I tell it to at higher speeds or corners where you don't brake. So maybe if I can get the low speed balance close enough, I'll stick a big splitter or wing on the front for a laugh.


@JB21 I'm not expecting it to be able to get much over 100mph to be honest    Top of 4th gear looks to be just under 115mph so that matches 'ok'. I will add some sort of panelling to the front and sides though I think, mainly to keep driving water out and my arms in should there be any sort of bump.


Done a few more bits this morning and over the last few days, tidying up the rear end by making a new exhaust hanger / mount, enabling me to get rid of the weird 'cage' thing, and added a rear 'bumper'.

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Also chopped the ends off the standard rear ARB and added / cut and shut some (well, one side is, the other is fixed) adjustable drop links. This has in effect stiffened the rear ARB a touch which will help with the understeer, and gives me a bit of easy adjustment at the track if required.

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The ARB clamps are my own design and have an egg shaped / shallow V at the opposite end to the clamping bolt, so they clamp 1/2" through to 3/4" bars at 3 points (the sides of the V, and the bolt itself). The standard ARB is 15mm and I have some 5/8" (15.9mm) and 11/16" (17.5mm) bar knocking about, so can always increase rear ARB stiffness in future if required.

That said, I am not a fan of this on RWD cars. I spent a couple of years with a previous Westfield doing the maths, building and testing ARBs, changing spring rates, roll centres, etc - and ended up coming to the same conclusion as Caterham did when developing their R400 (I found the document after I'd finished, d'oh!): Soft springs and stiff bar up front, stiff springs and soft bar at the rear. It seems Toyota agree. And Lotus (no rear ARB on the S2 Elise, for example).

My feelings around this are:

- The ARB acts in torsion, so (depending on mountings etc) this effectively doubles roll stiffness for the same increase in single wheel bump stiffness. The front end of the car is what you feel first when turning, so it gives good driver feedback, and the softer single wheel bump is great for kerb-hopping.

- Uncoupling the rear as much as possible aids corner exit traction. If you have a really stiff rear ARB and are leaning on the outside rear tyre on corner exit, the ARB is then trying to lift the inside rear off the ground - not ideal.

- Mismatched wheel bump frequencies front to rear (front softer) means the car settles evenly after hitting a bump. The front hits it first, but oscillates slower, so by the time both ends have settled they are back in unison again.

- All in, my preference (and Caterham's) is to end up with the front ARB contributing around 40-50% to front roll stiffness, and the rear ARB 10-15%, then front wheel frequency around 10% lower than the rear.

I think Mr Poo is the same front and rear, or perhaps higher wheel frequency at the front, but I will test this at some point and lob all the numbers into my handling calculator.

Could you not bang a C60 box in this from the 2ZZ Celica? Mine tops out at 104mph in 4th. Should give you better acceleration?

Certainly interesting looking and pretty loud as well with no cat etc!

Aero wise i guess with speeds being achieved on a 1zz it should have not have too much impact on circuit but will be interesting to see difference with full body car running same power etc, funnily enough at weekend i was watching the wind tunnel test video Cletus did with Leroy his non-panel corvette compared to a full body car, results were staggering with something like 540hp needed to just push the air out the way at 170mph terminal speeds he does on drag strip with no panels, then only around 240hp for full body car to do the same!

Here is video link for some entertainment

Yeah, could change the gearbox but... cost and can't really be arsed. Fun to see what I can do with the standard stuff! I would definitely fit something with lower ratios if it died though.

Thanks for the link Ian, that is interesting and fun! In my head I had 0.7 for a Cd, so that's not far off then. I wrote a calculator when I built a previous car, so given that we're 'there' thought i might as well lob some numbers in it...

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So basically that gives a top speed of 109mph if I have 140bhp at the fly, 20% drivetrain loss, drag coefficient of 0.7 and the 'usual' coefficient for frontal area of width * height * 0.8.

Dropping Cd to 0.6 gives an additional 5mph. I don't think it will be worth the effort, haha.

Standard Cd for our cars is said to be 0.353 (roof up, windows closed), giving a CdA of 0.592 (metric units), which gives a theoretical top speed of 131mph with 138bhp, from my calculator. Published figure is 130mph so that's close!

I'll chuck Leroy's numbers through when I get chance, be interesting to see how the calcs match the wind tunnel - but my Westfield was really close. I'd estimated a top speed of 132mph and it does reach the limiter at 126mph ish fairly easily, with a bit more to go.

There's an online calculator here too, which broadly agrees with my findings: http://warped.org/vw/calc.html

20% drive train loss is pretty high don't you think?
Its effectively the same a fwd hatchback in that respect.
No prop shaft light weight gearbox only 4 cylinders.
Not that it really matters just my thoughts.

Yeah I would agree - just went for the same number throughout and what most dyno operators seem to use. Be interesting to get an 'at the hubs' figure.

Quote from: AdamR28 on November 10, 2020, 12:01Yeah I would agree - just went for the same number throughout and what most dyno operators seem to use. Be interesting to get an 'at the hubs' figure.

It would be interesting.
Most dynos quote 20 or even 25 percent for losses makes them look good cos you never get a before mods run.

I'll have a ring round some local dynos, see if any of them have had a standard MR2 on them - obviously the actual numbers may not be right, but to see a comparison would be good!

Just leaving this here as a reference for myself. Maybe I won't need that brake bias valve after all...

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Quote from: AdamR28 on November 11, 2020, 06:12Maybe I won't need that brake bias valve after all...

The lager size at the rear might just do it.

I réally, RÉALLY enjoy this thread Adam. It is much too rare to see ome calculate to get into the ball park.
I love the formulae involved in the fysics as it adds to understanding and have my trusty ´91 TI-68 next to me on the sofa. Early seventies bought Irvings Tuning for Speed and got hooked on this from the gas/wave speed explantion/calculations in it.

As to aero, the lack of it will do away with the airfoil effect so yours will not have lift.
Adding some spoiler/wing at the rear would provide a breat/tear off ledge for the turbulent air´stream´ and reduce the drag. Because of the turbulence it will not result in much negative lift anywhichway so you can keep it flattish and it will not change your spring rate/suspension frequencey at speed.

Yes! 200bhp/ton!
I'm like, totally taking credit for that, thanks

So good to see proper engineering in a build thread. I'm thinking you must be in aerospace or automotive eng in some way? Leaning towards aerospace seeing the drag calcs... (Aero MSc here)

Also, I haven't checked in for a week or two, the accelerated timeline is amazing, how do you make such fast progress? I imagine it involves 100% less standing around scratching your head than my projects, and a better ratio than one hour completed work to ten hours researching online with 50 tabs open...

Love the little vid with you coming flying out the workshop at full chat haha

Quote from: iffyT on November 11, 2020, 18:07Love the little vid with you coming flying out the workshop at full chat haha

It was quite surprising yes :-)

As an aside, I certainly think the Cd is less than 0.7 if we compare to Leroy.
For one, the Munter doesn't have 2 massive turbos and a plenum chamber the size of a tool box sticking into the airflow, or a massive wing (or is this planned??). The Corvette also has a larger frontal area.

Have you thought about perhaps using some 3mm perspex like here: https://www.perspexsheet.uk/blue-750-perspex/ (I think you can find it cheaper), some rivnuts, and a heat gun and some old carpet and plywood as a former and go for a Ariel Atom type vibe?
Could help fill in some of those bits likely to cause turbulence, and maybe alleviate some of those horrified looks when you turn up at a track day (and beat their M3 by 2 seconds a lap)

Quote from: iffyT on November 11, 2020, 18:07Yes! 200bhp/ton!
I'm like, totally taking credit for that, thanks

Credit absolutely 100% yours, but sadly your dreams may have just been dashed... more on that in a bit.


I'm actually in the business of selling mountain bikes (weird looking ones with no seats for doing tricks on, specifically).     Though I kinda fell into that while at uni, starting up my business while 'studying' a very vague form of engineering - pretty much none of which I've used since.

However, I'm also a huge believer that if someone is interested in something then they'll put the time in to research and learn it themselves - cars and all things related holds my attention (perhaps too much of it sometimes!), hence the additional learning.

I go through phases of not sleeping very much, so getting up early and cracking on a for few hours before work is a good way to fill the time, and this time is wonderfully interjection-free. I love the solitude and peace of being up before 90% of the population (a virtual Covid-safe high 5 to all the other slightly autistic, borderline Aspergers or otherwise 'on the spectrum' sibling-free folks out there). With this project in particular, the lack of fucks given to neatness or cosmetics means I can just smash my way through stuff quickly!

Related to the above... I thought about posting this a few weeks ago, but having not been on the forum very long thought I'd leave it. But, I feel good today so why not. Cars help with my mental health. Tinkering and learning gives my mind something to do, a distraction, a focus, a challenge, a creative outlet, a release.

Mental health is something I've struggled with for more years than I haven't. Anxiety, low self-esteem, depression, an admittedly half-arsed suicide attempt in my late teens, then recently counselling, CBT, learning more about how the brain works, and support from those around me 'in the know' have started turning that around.

Now, this sounds a bit pie in the sky - and it can be difficult at times - but whatever traits you have which you may give yourself a hard time about can be positives under the right circumstances. A painstaking attention to detail, bordering on obsessive, and huge sensitivity to outside influences (interaction with mechanical things, noise, light) makes my brain ache at times and really takes the wind out of my sails, but on the plus side it has allowed me to build a successful business and do some truly unique things with cars, bikes and other mechanical objects. Everyone has a special talent of some sort - whether that is recognised by conventional education or not - and even though it can feel a burden, look for the positives!

Having opened up over the years about my mental health to various people - ranging from 'known them for 15 years' to 'randomers on a forum' - the responses have ranged from 'flip, I had no idea' to 'same here' to 'mate, that was brave, kudos'. I can't recall a single negative response. So if you're also struggling (seems common at the moment!) don't worry about speaking out, there's tons of support all over the place. Me for example - I'll never judge, so even if you just want to ramble a load of stuff to someone you'll never meet, and feel the weight of that burden drift away as you hit the 'send' button, you know what to do 

On other forums I have started a 'Mental Health Thread' for all to contribute to, and would be happy to do so again if deemed appropriate.


Anyway... back to Mr Poo. I'd previously had a read through some track day companies' T&Cs and thought the no bodywork thing was a bit borderline. I posted a few details on another forum which has a few TDOs on it and one point blank stated if I turned up, I wouldn't get on track, because the car 'looked poopoo'. No other reason. He couldn't argue with the safety aspect, and in fact agreed with me in some ways, but just it looked poopoo and that was that. Sadly, first impressions count, and being faced with an early bath from what should be a nice day out doesn't sound like my idea of fun.

So, the grinder was employed and a few kilos shed. Bonnet from 11 to 6kg, rear lid from 8 to 4kg, doors from 28 to 5kg (ish).

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And now he / she / it looks like this:

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Look how wonky the front end is from that shunt, haha.

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Decided the petrol cap mechanism was too heavy:

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And a shot of the standard side impact bars compared with what I've fitted:

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Doesn't look like I'll be able to stay under 700kg, but at least the car will be faster round a lap thanks to a much lower Cd!


Inspired by @JB21 's thread, I decided to look at some aero improvements: https://www.mr2roc.org/forum/index.php?topic=70241.0

First up, reducing drag and lift at the front. 'Free' power and better handling for very little work, can't complain.

As standard, the size of the opening on the front grille is tiny once it's been mostly blocked by the numberplate. We also have those alloy pipes running down the full length of the car acting as big heatsinks. I've also seen a document where a 2.0L plane was successfully cooled with a 5x11" inlet, and have the nosecone on my 200bhp+ Westfield blocked off to a hole smaller than that, so figured we don't need such a big hole... less air being 'swallowed' by the frunk area means less drag and less lift.

Hole is 6 and a bit x 16 inches, so I may close this more if the car sits at normal coolant temp.

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Couple this with a way to get air out of the frunk area... and hopefully it is a decent gain (ducting not finished yet).

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The location, I'll admit, is a bit of a guess. Having looked at other similar cars (VX220 and Elise) I figure the low pressure area is a little further back than front engined cars which have a higher 'line' between bumper and bonnet, so the duct can go a bit further back.

The pressure plots below also helped with location identification. Blue is low or negative pressure, red is high pressure.

Even the badge creates a significant high pressure area and lift! The little lip in front of the duct seems to create negative pressure thereafter, which is good.

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This looks fairly close to the MR2, especially with the bulges at both sides.

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Notice how far forward the low pressure area is (dark blue strip) on this car with a quite high 'line' and sharp transition from bumper to bonnet.

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This also looks pretty close to the '2, and has a fairly uniform pressure plot over most of the bonnet.

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So, with positive pressure going in (all the nose areas are bright red), and either negative pressure or neutral areas on the top of the bonnet, you can pretty much put the duct anywhere and air will flow out.

But why not help it on its way. The hole is pretty much the same size as the grille opening - I think, in theory, it should be a little larger as the warmer air on the way out has more volume, but I figure a bunch will escape down the sides of the rad and ducting (I can't be bothered making it really tight / neat).

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The little Gurney style flap helps to lift air up and over the hole, which generates negative pressure and 'sucks' air out. It is also a useful tool for breaking the airflow of the back of an object, reducing turbulence behind it and thus drag. I'll probably stick one on the very back of the car as well, for a laugh, and obviously on top of the 'windscreen' to help lift air and water over the occupants.

And some really scientific testing 

Without flap... turbulent air immediately upon separation from the bonnet surface.


With flap... air is sent up and over - creating slight negative pressure where the hole is.


I think. I'm no aerodynamicist that's for sure, but it makes sense to my brain 

Mental health is like the last medical taboo.
Still people out there that don't believe in such a think.
I've been in therapy on and off for 18 months now and some days are hell and others are heaven.
Good luck on your journey.

I was getting excited for a minute there, I thought you had posted some ideas for painting the car....

Wind tunnels are so last year!

Quote from: iffyT on November 11, 2020, 18:07Yes! 200bhp/ton!

Over 250 is where the real fun is 😉

That's where mines at although I've added power not lost weight.

Quote from: 1979scotte on November 13, 2020, 16:03Mental health is like the last medical taboo.
Still people out there that don't believe in such a think.
I've been in therapy on and off for 18 months now and some days are hell and others are heaven.
Good luck on your journey.

It is only recently that I have made use of "Recent posts" and reading posts "backwards" is sometimes not the best way.
This post being a particular one of note, completely out of the blue we are into what can be a "taboo" area.
Having now read the thread in sequence I can see that we have, at least two, I shall call them brave members who tell other members of some of the troubles they experience.
Having met and regularly exchange  banter with one and followed the interesting and positive thread of the other I was surprised. But  that they feel that they can " speak openly" on this Forum , must show the generous and understanding nature of the Members.
Hopefully,  the old saying that "a trouble shared is a trouble halved" will prove true and that sharing with however Members are active on here, will severely help reduce their troubles.
Thank you for sharing.

Much better with the bodywork back on mate. If you make a front splitter make me one too, lol.

Fair play with opening up on mental health too. I also suffer with it after losing a lot of loved ones far to early in horrible circumstances and i was also caught up in an industrial explosion/fire in work which resulted in fatalities and injuries to good friends. My boy also lives with ADHD so i understand what you're going through.

Having met up with you at three sisters you'd never know you struggle with mental health. My mate also struggles and he can be a bit awkward talking to strangers, you didn't come across like that at all.

Found this Adam if any good to you.

Quote from: AdamR28 on November 13, 2020, 15:17the responses have ranged from 'flip, I had no idea' to 'same here' to 'mate, that was brave, kudos'.

Put me down for 'same here'. Depression sucks balls but I do find it comforting that some of the most driven, capable and nice people I've ever met suffer similarly. My friends and family help me get through the rough patches, although unfortunately my project outlets sit gathering dust when times are hard. One thing I wish I could change.
All the best mate, and back at ya if you or any other of you mr2 peeps ever want to chat, PMs are open.

Car looking more svelte with the body panels on!

Quote from: iffyT on November 13, 2020, 23:42Car looking more svelte with the body panels on!

Recogniseable as an MR2 again.
The unwanted lift caused by the airfoil OEM shape is spoiled by the absence of the windscreen anyway.

Quote from: AdamR28 on November 13, 2020, 15:23So, with positive pressure going in (all the nose areas are bright red), and either negative pressure or neutral areas on the top of the bonnet, you can pretty much put the duct anywhere and air will flow out.

Hence I cut two vents where I best liked them aestetically.
Together they are still smaller than the entry but it is more than nothing.