[project] 205 Mi32 Project - The Twin Mi16 Engined 205

[bales 1]

what makes you say that?

 

You would theoretically get a slightly more agile car and a quicker turn in - though less stable through fast corners.

 

When we built our formula student car at uni we had quite a bit narrower rear track than the front as we need such a manouverable car and we never get to high speeds. So whether is good on a road(ish) car I wouldnt like to say.

[brianthemagical 1]

i think, of the top of my head, that 306's and 205's are wider at the front.

[Guest rems11]

You are very crazy because it 's hard to synchronize 2 engines!!!

[Subby 0]

just read the whole project mate, and awesome work. Well done!

[Dave G 0]

mental little project you have had going on there, nice thread to back it up to

[NeilGTi85 5]

That is some insane project, what sort of RR figure's did you get?

 

Ive seen the "Pug1off" twin V6 306 and that is on par with your twin MI.....

 

Neil

[cybernck 402 1 Cars]

haven't got it RR'ed... yet.

[Grim.Badger 15]

i think, of the top of my head, that 306's and 205's are wider at the front.

 

I know 205s, especially base models, are a fair bit wider at the front

 

1.6 GTi (I think)

Front track: 1.382m (54.4")

Rear track: 1.339 (52.7")

 

Cybernck - I've probably skimmed over it, but are you planning on putting a turbo on the front engine as well? I would presume not as you would then surely start losing traction Although I suppose if you are sprinting in staight lines then that isn't as much of a concern as usual I suppose

[cybernck 402 1 Cars]

yeah that's planned too but we first need to shoe the front wheels into some Toyo R888's

as the traction is bad as it is. maybe we'll fit a supercharger on the front engine, to try that

route too... or maybe simply "cheat" with NOS, as that solution won't give us more traction

problems and the engine would stay standard for normal single-engine driving .

[Guest johnston_evo3]

Been reading this and re-reading this and just got 1 comment to make AMAZING

 

I was thinking of doing something similar with all the bits i have lying about except only engines I've got are 2x1.6gti's.

 

So I was wondering with hindsight being the wonderful thing that it is, layout wise is there anything you'd change???

 

For example i see you've been saying about her squatting and loosing grip at the front would you change the rear suspension from standard front to something else with anti-squat geometry built in????

 

 

Iain

[cybernck 402 1 Cars]

thanks for the compliments .

 

well for one, we'll definately need to get some coilovers for the rear too,

to be able to play with spring rates (not sure if softer or harder is better

in our case?) and height ofcourse, but other than that, a pair of R888's

would definitely help a lot .

 

got any constructive ideas?

[Batfink 201]

you probably want softer as you want the weight transfer to move backwards over your rear wheels to help traction.

[cybernck 402 1 Cars]

i would want that if i had RWD... and the opposite with FWD .

 

but with my FWD+RWD, there's enough traction on the rear even with the turbo on

and not enough traction on the front with a standard DFW engine, hence why i don't

want to turbo the front engine - it might make the car a lot slower off the mark .

[Guest johnston_evo3]

I remember we used to turn (i think) the bound up on 2way proflex at the back on a evo 3 rally car i used to prep to stop her lifting the nose under acceleration but that was so the spring rate could be kept for over the bumps, something i dont think you'd need to worry about.

 

I've been trying to think of a way to do a trailing arm or 4 link setup (think grp4 mark2 escort) but set the links to keep body level rather than hunch down at the rear.. As i'm looking to use mine for track days dont fancy losin the front end grip out of a corner.

[Grim.Badger 15]

i would want that if i had RWD... and the opposite with FWD .

 

but with my FWD+RWD, there's enough traction on the rear even with the turbo on

and not enough traction on the front with a standard DFW engine, hence why i don't

want to turbo the front engine - it might make the car a lot slower off the mark .

 

I'm no expert or mathematician but I would assume that you treat the car according to which engine has the most power, unless they are very close. So for example if you have a lot more power at the rear then treat it as a RWD car could be talking bo****ks though.

I would say that its worth looking into why manufacturers chose certain 4x4 bias' as it may give you ideas, especially if you can find out the bias for things like the GrpB Golf which iirc had two engines but I suppose a rally car has different needs to yours. I'm probably just telling you things you've thought about though

 

Edit: Hmm, just been trying to find that Golf on the internet and I can't, I think it may have been my imagination but I'm sure VW produced a prototype for a twin engine Golf for GrpB just before the rally was cancelled, but maybe I'm thinking of the Visa that had two engines

Edited March 31, 2008 by Grim.Badger

[NeilGTi85 5]

I have a video of the twin engined golf at home from a 1/4 mile run.....ill try and find it later. It was a road going car though,

 

Neil

[Grim.Badger 15]

I got a bit mixed up there, started talking about 4x4 transfer box bias and then ended up on twin engine cars I know what I mean though My point is basically that if you look at the choices manufacturers make when deciding how much power needs delivering to each pair of wheels then you at least have somewhere to start with sorting out your suspension ratings

[cybernck 402 1 Cars]

NeilGTi85> he's not talking about that Golf, but i know which one he's on about .

 

Grim.Badger> the main difference between 4wd and our fwd+rwd car is that 4wd ones

have a center diff which is, although there's a pre-set front:rear ratio, usually able to

alter the ratio to get the best traction, while in our situation it doesn't happen .

[Guest johnston_evo3]

The other thing with looking at the torque bias on 4wd cars is usually its manufactered for your run of mill joe bloggs who thinks he can drive fast and therefore has a "safety" element built in

 

i.e. 50/50 or 40/60 will cause understeer due to the bias plus weight of the engine over the front axle to which most folk will lift off the power and normality will be restored..

 

"proper" rally developed road cars cossies interglales etc usually go with a 60/40 to the rear for the chuckability something you dont need for drag racing.. plus lsd in the centre diff something which doesnt exist in cyberncks car obviously

 

BUT!!!!! correct me if i'm wrong but it sounds like cybernck's main problem to keep grip at the front is more to do with weight transfer

 

my theories being fix weight transfer keep all 4 wheels on the ground OR tune the 2 engines different rear one for off the line grunt and then the front one for the top speed once suspension levels out again....

[Grim.Badger 15]

So if I'm reading this correctly, you want the rear engine to reach peak, or at least high power sooner (so the turbo engine is probably well suited) than the front engine whilst at the same time making sure that the rear engine doesn't pull the nose up, or if it does then the front wheels stay on the ground.

 

So if I have my physics hat on, as the rear engine tries to pull up the nose the stiffness of the springs will effect how the rear engine will pivot the car, soft springs will compress as the rear engine revs up and will dig the rear end down rather than lift the nose up whereas hard springs will stop the rear digging down increasing the amount that the front lifts.

The front end is a different storey, you want springs that have a long unsprung length so that they keep the front wheels on the floor as the nose lifts, but at the same time they need to apply decent pressure to the wheels otherwise they will just slip and skid; I would get stiff coilovers with stiff helper springs (if you can get helper springs in different rates). I suppose you might not need a long unsprung length or helper springs, it all depends on how much the nose lifts, but I would certainly say hard springs would be best.

I'm no expert, but I think I'm right; the problems will be getting a decent ratio between front and rear springs.

[cybernck 402 1 Cars]

yep that's exactly one of the two ways i see it .

 

the other way is doing it what FWD boys do - they obviously don't have drive on the rear wheels

so don't need the car to squat down and aid traction, but at the same time they don't want the

wieght transfer to lift up front end and loose traction - so what they do is have the front low and

hard while the rear is very hard but high up, to counteract the weight transfer.

 

so when applying this logic to my case, i realise/think that soft rear end actually makes the front

wheels spin more easily, taking some weight off of them, while with the rear end high up and hard

both ends would benefit?

 

hmm...

[nimmo 0]

well done on the whole project, i will be starting my own very soon you have definately given me some idea's

[holland_gt 0]

scary car by the sounds! Loved the project, well done!

[de Noir 0]

Nick, hats off. I adore your bravery... Me, I wouldn't dare to drive this... thing...

Edited September 10, 2008 by MH_

[pip470 61]

First of all great project, It must of took a lot of skil and dedication to get this far. I would like to give a suggestion that i would like to try as it seems good in my head. The suspension setup i would like to try is jack the rear end up like mine, ( have a play with different ride heights) lower the front with really stiff shocks like the spax coil overs i have. But this is where the differance to my set up is, keep the rear shocks soft, so that whan you launch of the line, the rear will sqaut but hope fully the front will not lift. so what you have is quite a level car. My only concern is that when you lift off the power the back end will bounce up and become un stable maybe in between gears. I dont think this will be too much effort to try at a race track and if it was clear it didn't work, Its easy to put back. Does this sound reasonable or a load of rubbish? Phil