Mr Poo the MunteR2

[AdamR28]

Some pics for @Petrus ...

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[Maurici]

Yiiiihaaaaa!!!!
Im so excited about crashing this one. Difuser and all. Will be absolutely spectacular!!

[Petrus]

See what you did Adam. Thanks! Much appreciated!!

Unfortunately that spot is not working in my case: I need to be able to swap for the OEM bonnet and the inner frame thwarts it. Also not a lot of ´meat´ from the edge for a fiber one.

May best be using the hinges after all. Lange flat head bolts may look not too bad.
Will be using those push buttons you have at back, at the front.

Am working on a tonneau cover. Maybe something for you to close the tub? If we get the first made, the second will be less pita. I´d do it without eyelets/buttons so you could fit it as suits yoú.

[shnazzle]

Loving it! More videos

[Topdownman]

I am still trying to work out where the half barrel is going!

[Maurici]

I am still trying to work out where the half barrel is going!

We drank the content ages ago... is now a surplus.

🤣 jokes aside, I have also spotted it, and wondering where it goes...

As I know you love mx5... im going to leave this here to be hated.

I expect a similar one in cadwell but with MrPoo.

Ladies and gentleman... MrPoo's inspiration, the original Munter. (Im now the lucky person fostering Adam's original pride and joy)...

Cadwell is a bit less power dependant as you rarely have your steering wheel straight, I expect the MR2 will keep up much better with heavy machinery.

@AdamR28 r you building the spare shell already?

[cptspaulding]

Love this thread.    

(Sorry, I'm very late to this one)

[AdamR28]

I am still trying to work out where the half barrel is going!

Passenger seat 

Managed to get a few more bits done on the car before Cadwell, namely an extra deflector for the front duct, tweaked rear ARB setup, and a set of louvred arch vents, aka The Cheesegraters.

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Awful, eh? Still, they are a talking point, and they won't harm.

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Tried to remove the rear ARB, bolt snapped, didn't have time to fix it properly.

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So had to do the welding in situ. Worked ok. The clamp slides up and down for adjustment, only one 13mm spanner required.

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Ready to rock! Bits of red tape because I kept walking into the Max Power Time Attack ALLLLthedownforce rear diffuser. I take the piddle but it does actually work, which is nice.


Anyway, yesterday (Cadwell) came round rather quickly, but once we'd left the house felt pretty chilled. There was a bunch of half a dozen of us who camped over the night before, had a BBQ, chatted some crap about cars and other things. @Maurici came along for 'Leg 2' of our car-swapping session, and apparently managed an amazing night's sleep in the back of his car. Legend.

The day started veerrryyy chilly, with talk of shivering in tents and extra hats, and even a bit of frost very early on, but was mostly dry apart from a couple of hail showers which just so happened to coincide with my sessions... 

The car went really well - the balance is better than last time, but it is still a bit too lairy. My thoughts now are that there is too much roll in the car, allowing the rear to toe out (a lot) under hard cornering and transition to throttle on the exit (squat). I have a set of Whiteline ARBs I'll play around with before next time. The front deflectors ground out a LOT (which sounds horrible - you can hear it on the videos) and the front splitter got a bit scuffed, so I'll raise it 10mm or so. Other than that, not much to do.

Buffeting in the cockpit is better (bearable now), brake pads hardly worn at all, tyres barely worn and they are actually pretty good (datalogger shows over 1.5g lateral through Coppice!), stuff didn't fall off (although Maurici gave it a good go, managing to bump a tyre wall mid spin - and somehow not damage the car at all, I'll let him explain that one!), and oil consumption has even reduced a bit. Slightly disappointed at that, given the previous oil burning rate would have seen a full oil change every 4 track days, which would have been perfect self-maintenance - never mind.

Minimal damage from 'the off'!

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I have a few more posh things to add to the 'Kill List', including a Cayman GT4, latest Focus RS, an M140i, and it appears the little Snotrag was also lapping faster than some 200bhp+ kit cars that were there. Bonus.

Must be the eXtreme MotorsPOO stickers and mirrored 'FULL SEND' that Maurici made up and stuck on. Thanks mate 

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Just realised I forgot to mention the side air curtain generator things and a hugely cut out front wing. There they are. I say wing, because I didn't have time / couldn't be arsed to do the other one. So it'll probably stay like that forever now.

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Video from my perspective...

And Maurici has one which I'll let him post up if he likes.

Cheers for reading!

[Maurici]

Yep. I did manage to crash (pretty heavily from the inside) in barns... did about a 360 and managed to hit the tyre wall while spinning in the grass... wall deflected a lot and I was expecting the same result in the car. I still cant beleave i didnt damage anything. Took the car out of track on my own... I was medically checked and all. Despite i got a new wristbant and i was cleared for driving again, I called it a day. Again... sorry @AdamR28, it could have been much worst. It now feels wrong that I joked about it in my last post.

Pretty ashamed about the whole thing... specially because for what Adam told me, watching from the outside they were expectind the crash in hall bends for several laps.

I was driving waaaaaaay to hot and the car is still a bit of a handfull. Mostly controlable... till you flogg it in to the barriers. Pretty fun tho.
This is my morning session. Sadly the crash was not recorded...

[AdamR28]

It now feels wrong that I joked about it in my last post.

Makes it even funnier if you ask me! Really not a problem mate, no need to apologise - only thing that matters is that you aren't hurt and will still continue to drive like a lunatic again in future

[shnazzle]

That looks like such amazing fun. Good driving!
Love the thread. It's properly different but brilliant

[Gaz mr-s]

@AdamR28   is Maurici needing to be smoother going in to corners?  I can understand you using opp-lock in the wet, but is it needed in the dry?

[shnazzle]

@AdamR28  is Maurici needing to be smoother going in to corners?  I can understand you using opp-lock in the wet, but is it needed in the dry?

Looks like it was intentional. For fun

I'd be doing the same for laughs and practice.

[Maurici]

@AdamR28   is Maurici needing to be smoother going in to corners?  I can understand you using opp-lock in the wet, but is it needed in the dry?

The car's back end is extremely loose.
Even without wanting it, the rear rotates A LOT... and the line between rotating it with throttle and having the back end completely off was waaaaaay to fine
Shall i be smoother? Probably... but I maybe also need more talent to keep the car rotating without having to go completely sideways...

Or just stop driving that bloddy thing before it kills me🤣🤣🤣

[Roj]

I love this build. Home built, light, quick, cheap, totally original, stone great engineering, doesn't look like much but pisses off big bucks cars... Perfect!

[Petrus]

Even without wanting it, the rear rotates A LOT...

That comes with a low MR2 ;-)

As you mentioned already, playing tith the ARBs can help. Going front relatively stiffer would balance the car towards more rear grip.
Mind you, it will still rótate just as quicky, that is the low moment of inertia, but the rear might let go less binary.

Also tyres. Find a set that has a broader top.

Lastly the driving.
The tyre adhesion graph has TWÓ points with the same grip; one before the top, one over. The latter is at a larger angle of slip so scrubbing off more speed ánd it is at the downward slope meaning more slit anle = léss grip = going quicker.
Driving at the one on befóre the top is exactly the same max corner speed, less power needed to maintain it and it has more margin of control.
Works like that on motorcycles too :-(

[Maurici]

Cheers @Petrus .
The MunteR2 has pretty much standart ride height... according to Adam, the toe out transition in roll (bump) with the current geometry is what screws the back end.
The current plan aparently is stiffen quite a lot the rear ARB keeping the suspension as it is so it will limit the roll and make the back end more predictable.
Obviously front will have to be stiffened equaly to balance the front/rear grip. Adam will explain it way better than me.
We are familiar with tyre behaviour too. Will see how many times I crash it till it behaves how we like .

Eres de Malaga? No es muy comùn encontrar españoles en foros ingleses!

[Petrus]

Cheers @Petrus .
The MunteR2 has pretty much standart ride height... according to Adam, the toe out transition in roll (bump) with the current geometry is what screws the back end.
The current plan aparently is stiffen quite a lot the rear ARB keeping the suspension as it is so it will limit the roll and make the back end more predictable.
Obviously front will have to be stiffened equaly to balance the front/rear grip. Adam will explain it way better than me.
We are familiar with tyre behaviour too. Will see how many times I crash it till it behaves how we like .

Eres de Malaga? No es muy comùn encontrar españoles en foros ingleses!

Thanks Maurici.
I think that it the wrong way round. It will redúce grip at the rear.
The simplest is to cut down the spring a bit to set the ride hight a bit lower. That will address the geometric issue.
Than stiffen the front ARB móre than the rear. That will give relatively more grip at the rear.

The ARBs are so simple to play with. Just try.

Pues si soy residente en la provincia de Málag desde 20 años pero nació en los Paises Bajos. Dus Nederlands gaat ook perfect ;-)

[Maurici]

Cheers @Petrus .
The MunteR2 has pretty much standart ride height... according to Adam, the toe out transition in roll (bump) with the current geometry is what screws the back end.
The current plan aparently is stiffen quite a lot the rear ARB keeping the suspension as it is so it will limit the roll and make the back end more predictable.
Obviously front will have to be stiffened equaly to balance the front/rear grip. Adam will explain it way better than me.
We are familiar with tyre behaviour too. Will see how many times I crash it till it behaves how we like .

Eres de Malaga? No es muy comùn encontrar españoles en foros ingleses!

Thanks Maurici.
I think that it the wrong way round. It will redúce grip at the rear.
The simplest is to cut down the spring a bit to set the ride hight a bit lower. That will address the geometric issue.
Than stiffen the front ARB móre than the rear. That will give relatively more grip at the rear.

The ARBs are so simple to play with. Just try.

Pues si soy residente en la provincia de Málag desde 20 años pero nació en los Paises Bajos. Dus Nederlands gaat ook perfect ;-)

Well. Will leave the geo setup and discussion to Adam, who happens to know a bit more than me on the topic

Im from Mallorca, but life got in the way and ended in Cheshire, uk... hope you enjoy spanish weather a bit for me... 

[Iain]

Had a good long read of this thread today. Great work, love the out of the box thinking and great ideas of building what and how you want it to be.

[Petrus]

... hope you enjoy spanish weather a bit for me... 

I will, I will, it´s a rotten job but sómeone will have to do it :-)

Staying with Bubbly; Antequera gf, and for sure enjoying doúble ;-)
This evening open air concert en ´el Cortijo´.

Tomorrow in the mountains with Mountain Girl; Vva del Trabuco.
Lunes, a por Torremolinos.
Ademá un dia de semana que entra a Motril. Iré por carreteras comarcales de Granada con el MR2.

[Gaz2405]

Watched this round Caldwell on YouTube last night, looked to go really well!

[AdamR28]

Thanks for the input and comments guys - glad this thread is offering at least a little entertainment!


I'm going to brain-splurge a bit now, but hopefully some of it may make sense and even assist another member in future.

So, the main issues with the car at the moment... these can be driven around but that's not really my style, I like to feel completely in-tune with the car so I can take my brain out and just enjoy.

1) It bottoms out all over the place. Solution: Raise the front splitter a bit. Simples.

2) It oversteers like buggery. Solution: A bit more long-winded.

So we know the rear of the MR2 toes out in bump. This is a desireable characteristic for a low powered sports car, allowing the rear to roll through the corner without scrubbing speed off. Porsche spend millions developing these sorts of 'active rear steering' systems for their cars, we have a budget version already built in.

It seems that one of the main reasons for toe out in bump is actually to produce the opposite effect, toe in under rebound - what this does is help to tuck the rear back in if a less experienced driver gets into oversteer and lifts off the throttle. The lift shifts weight to the front end, making the rear suspension extend, and the outside rear wheel goes towards toe in, keeping things in line.

However, when you have an experienced driver who keeps his or her foot in during oversteer, this makes the car bite / squat more at the rear, compressing the suspension further, and giving more toe out, which means more oversteer!

This reared its head at Cadwell many times, and was more prevalent with a passenger in - more compression on the suspension due to more weight in the car = more toe out.

Compare the oversteer here at 1:59:

To that here 4:36:

Perhaps on a more 'normal' track version of this car the whole rear toe thing isn't too much of an issue, but with very soft suspension and aero (which actually works - the car pulls 1.5g through Coppice and 1.3g on other flat high speed corners - it should only be doing about 1.0 - 1.1g on these tyres!), the wheels are moving up and down a lot, and the suspension is under considerable load. Note comparison to other cars: https://fastestlaps.com/lists/top-grip-kings

Now, the standard rear bushings are pretty floppy, for compliance on the road. Under the sorts of loads I'm subjecting Mr Poo to, the rear end is going to be flexing all over the place. I think I need to add some more static toe to get the rear end to not go into wild toe out under load. I could spend ages and loads of money adding fancy bushings / rose joints etc, but I can't be arsed. That isn't what this car is about. So a bit more rear toe in it is.


There is also a lot of chat online about adding loads of roll stiffness (springs and / or ARBs) to the front of these cars for track use - which would have the effect of adding understeer / reducing oversteer - but I'm not sure. I like the car to rotate when I tell it to, and I hate understeer. The car is for fun, not racing, so while it may be faster with some more 'push', that isn't the aim.

The car also doesn't have excessive body roll, and body roll is what tells the driver what's going on with the car (more body roll = more feedback). So I am a little loathed to stiffen the car. See below.

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(Photo copyright MSV, I have since purchased this photo)

The rear toe change is also very easy to do - so that's my next step. Completely at odds with what 'the internet' says I should do, but hey, isn't the whole car?



A couple of questions in the posts above...

Opposite lock in the wet or dry is no different. The car gets a slide on to x angle, it needs y amount of steering lock to keep the car pointing forwards. You just (usually) see it more often in the wet because the driver has more time to react to a slide (lower grip levels means the car transitions the point of adhesion with less violence), thus they let the car get closer to the limits more often. In the dry, the car can get away from you very quickly (especially with stiff suspension and sticky tyres), so most drivers don't go there for fear of binning the car. The 2nd video in this post at 4:36 (and also a few times at 1:02) shows a lot of opposite lock, applied and removed very quickly - in the wet this would take place over a much longer period of time, so it is also more noticeable. But let me tell you, in the car this is pretty scary!

Maurici is pretty aggressive with the car. That's his style. He prefers a car that has more understeer because of this - it means there is a wider window before it gets out of hand. This in itself is a testament to his skill and car control, 1) that he has generated a preference and 2) he can still catch a car that oversteers a lot!

The ride height of the car I mentioned earlier in the thread and will go and have a look after this post, but from memory it is technically around 10mm lower than standard. The car just looks stupidly low because of the splitter and tiny wheels / tyres (2" smaller diameter than standard). I knew lowering it a lot would significantly upset the geometry, so didn't want to do this.

Not sure when the next outing will be, so this thread may lie dowmant for a while now...

[AdamR28]

Total: 306lbs / 140kg of downforce! That would be enough to lower the car about 15mm at speed, which would be, er, interesting.

Just spotted this...

It looks from photos that the car does drop ride height noticeably at high speeds.

Estimating 1.0 - 1.1g (say 1.05) of lateral g without downforce in an 830kg car (inc driver and fuel), but it actually pulling 1.3g consistently, means the car 'weighs' (generates vertical load) of more like 1020kg at high speeds. I can't say that is 190kg downforce, but there seems to be around 190kg difference between the amount of lift the standard car produces, and any amount of negative lift (downforce) Mr Poo has. Significant!

[Maurici]

Maurici is pretty aggressive with the car. That's his style. He prefers a car that has more understeer because of this - it means there is a wider window before it gets out of hand. This in itself is a testament to his skill and car control, 1) that he has generated a preference and 2) he can still catch a car that oversteers a lot!

I'm now over the moon... taking in account I had a shag with the tyre wall...

Thanks!