Fake - F7R Motorsport Daily

[pettaw]

I think that shielding was meant to be connected at one end only in that, which was weird for me, however it did make occasional misses go away. Who knows what other benefits such may have.

For me too. Cleaned up my crank sensor signal beautifully.

[zombeh]

I think that shielding was meant to be connected at one end only in that, which was weird for me

If you ground the shield at both ends you will have a ground loop, this is a bad thing(tm) and will make it noisy. You should ground it at one end only, ideally the shield for the crank trigger should be grounded to the nearest bit of the engine.

[volvosneverdie]

Bumpio. This thread is quiet.

Tooo quiet.

[Chris_C]

Yes, it is

[sven360]

Get the welder out,Joseph!!

That'll warm ya up.

[Chris_C]

2 new problems have cropped up (well, 3, as those in the know know... I will update the thread about the third very soon)

Bumpio. This thread is quiet.

Tooo quiet.

Well, I hadn't posted this as it's still not sorted, but there is a reason I havn't been updating my thread.

On the 7th Oct, Fake was written off whilst stationary in traffic. I was very lucky to have the supportive seats I do, my neck got away with it pretty lightly, however my lower back not so much, I still have issues with it if I don't sit with good posture.

Officially she is a Cat C write off. She looks *very* ill from the outside. I have pictures, but until I finish sorting out the insurance issues they will not be posted. So, after 8 months of not having her on the road, she was there for 8-10 weeks before *someone else* broke my car for once.

It's likely I will rebuild a valver, however I havn't worked out if this will be for myself or for recouping some costs. I just havn't driven the car enough in the last 14months to remember why I enjoy it and infront of that it hasn't been right for much longer. The wheels, suspension etc make it significantly more grippy and faster than a stock 300, but it doesn't handle like I want it to, nor how a stock car does. Whilst the F7R is an awesome engine I'm just not sure it's suited to the 300, at least the level to which I will drive the car and the reliability I insist from it. Tbh, I just need to think it through, but even if Fake does come back, there will be some fairly major changes.

I'll put an initial idea of my wheels are likely up for sale. You all know what they look like, most preference will go to someone able to swap for Leo's along with something else, either pound notes or shiney things. How much soley depends on the condition of the Leo's. I have 8 in total, one has a fairly epic bend however so it would be wrong for me to sell two sets.

[Speedy88]

Sad face, although I already knew. I know how much the car means to you, it's a great shame when things like this happen beyond our control.

Most of all, I hope your back gets better man, I suffer from a bad back too and I know how frustrating that can get.

As for your wheels... interested. Everything hangs in the balance though as the exchange for the GLS hasn't happened yet, nor do I have any money...

[jtbo]

Be careful with your back, old wounds can be quite annoying when one gets old, so best to do all tests and fysio etc. if possible, might save a lot of trouble at later.

I'm thinking that board members are having quite bad luck with other motorists, VND's car got damage once when parked, I think there has been others too, either bad karma or general level of drivers is not too great in there, either way it really pisses off when someone else does such things.

My co worker got rear ended at traffic lights, he has Volvo S40, luckily his tow hook did most of impact and car that rear ended his car was totalled, radiator, bumper etc gone, bags deployed and car was relatively low priced. Driver claimed that he did not see the car, now co worker's S40 is bright red and that was winter time so ground and surroundings were white, probably easiest colour to spot in those conditions, so anything is possible in here too.

Most important is that you are mostly okay, it could be always worse.

Handling wise 300 is not perhaps easiest to make handle perfectly, at front there is limited bump travel, which easily is affecting handling, especially when lowered, it can cause annoying situation where car 'randomly' starts to understeer, etc.

Also without camber changes it is quite difficult to achieve point and go kind of handling. When I did some measurements I found out that camber gain is positive with bodyroll, which means that if you have -1 degrees of front camber (I think car has -0.2 degrees or so at standard form), with bodyroll you end up with closer to 0 or even positive. Now when car is lowered it loses some negative camber because of this, which makes handling to suffer, but it is difficult to pinpoint as other changes happening same time are masking this.
Well, that is if my measurements were even close to correct, that is not always the case.

However what I have found is that to make 340 or 360 truly handle one needs to do serious modifications to front end, surely rear end too, but front is bit of challenge because there is need to get more bump travel and getting more of that is not very easy, also camber needs to be lot more negative and geometry should be played with so that one gets more negative camber with bodyroll, at least those are my impressions.

Rear would need some more bars but only needed if there is lot more power and lot of grip, but I think it should be quite ok for soft surfaces, springs are rather soft and there is lot of travel and axle weight is not too great, good shocks and properly set up should help with grip on potholes and at launch etc.

However BMW 300 is probably easier platform as is even 200 series Volvo, alone huge amount of them used in motorsports has put lot of engineering brains to use long before these times, so those might be better suited for well handling car, however 240 is bit of boat. Today easiest way is of course to pick some old Skoda Felicia and put rallying stuff from rallying market into it, cheap to run and build, boring FWD but not awfully slow as being small and light.

It is then matter of choice, odd rwd car, mainstream rwd car or mainstream fwd car, surely mainstream is easy way, but is it really right way, would one get same satisfaction from there than from these odd choices we have made with 300 series?

There must be reason why 300 was first chosen, is that reason still most important or has years changed that?

Maybe there are some thoughts that would help or just make more mess, however more point of views is always better base to choose, maybe also driving good condition standard 300 series car might be good for refreshing memories why that was your choice in first place

[volvosneverdie]

Shit dude.

Bent update.

Glad youre alright though. Could have been worse I suppose.

Those wheels are seven shades of frickin awesome. Theyd look the very balls on Speedys new ride.

Hope you have a good xmas man, youre due a bit of goodness now eh?

[mat_91]

bad luck dude that my worst nightmare after working on a care for ages
hope it can be fixed

[Chris_C]

Thanks chaps,

Jani, I've still not got internet at new house, but I'll try to reply to that when I do. You raise a lot of good points that I didn't have clear in my mind and I need to think about!

[jtbo]

Thanks chaps,

Jani, I've still not got internet at new house, but I'll try to reply to that when I do. You raise a lot of good points that I didn't have clear in my mind and I need to think about!

Just remember that my measurements can always be way off. Also now that I checked I did remember camber gain wrong way around, it is only few millimeters change at edge of tire, but it is better to measure this properly first, my measurement included only top of tire and only when car wheel was on ground and wheel at air, one would get much better results by removing the spring and then measuring full motion range, both top and bottom of wheel and full rebound, neutral, full bump positions, ideal would of course be gain of 1-2 degrees of negative camber when cornering unless one is already running aggressive camber setting, that would work wonders in terms of cornering grip add toe to be neutral or bit toe out and it should be quite nippy and quick with direction changes, that combined with good caster angle there is by default should help to make car bite into corners well.

Rear should have -2 degrees of camber, now camber is affecting how car will turn in and how it will stick into corner and if you set front to be more than rear then you might end up with quick oversteer capabilities, but lack of rear arb and one at front is partly balancing that as is stiffer front springs, but remember with springs that there one must to get weight distribution to be able to know if front really is stiffer than rear.

I don't know how to put spring units to some lbs/in kind of, but GLT standard front were ~26kN and GL standard rear were ~15kN, now I wonder if these were kN/m or kN/m^2, anyway the SI standard ones from my memory, which you know to be rahter poor

Anyway good thing with playing around rFactor and alike is that it makes easier to get what effect different changes are in general sense, also one need to really do the work and learn from real world suspensions to be able to work with rFactor suspension, I doubt it will give precise exact effect but to get what camber and toe does, what different spring and damper setting does, those one can get there, however as there is no exact way to define suspension movement ranges, that is going to cause sim to be bit off among some other issues, especially with tyres, but I think that even live for speed being as free demo would work in there to get to know what each setting would effect, I think it is much easier that way than trying to figure out terms used in fancy books about car handling.

Then there is importance of roll centres, I don't know if you are familiar with those? This image should be helping there:


What ever change you do, if it causes roll center to start moving around more with suspension travel, then handling is going worse, if you can make it stay put then handling should be much better, control of roll center movement separates race car from road car, imo.

There are lot of great articles if one searches roll center with search engine of their choice, that is really important and often overlooked aspect, but if everything else is sorted these can still mess up the handling.

Some links that might be useful.
http://www.circletrack.com/techarticles ... index.html
http://www.neohio-scca.org/comp_clinic/ ... cs2007.pdf

It is lot easier to work out all the angles if one has access to some 3d modeling or cad program, it is much easier to measure from strut to strut distance than trying to figure out distances from side of car or even trying to get measures from imaginary center line of car. Surely one can do that with paper too.

All these measurements will help to some extent. Scrub is one that is giving steering feel.


Trail is effect of caster, this is what makes wheel to countersteer automatically.


There is indeed quite many things to consider when making car to handle, measuring all realiably is going to be quite bit of work, but it is better to make bit of work there than just slap some random pieces together hoping it will work, or slapping pieces together as others too that too, science is there so one can take measurement and plan things ahead then build and measure difference to know if it really did improve as feel of one's butt is alwys subject to errors.

Measuring alone is not the easiest thing, it is so easy to get lot of errors there and doing that on drive or in small garage is quite a pain, however there is lot to be gained from measurements.

These are my measurements, subject to great errors naturally and as I typed names while measuring, they can be bit difficult to understand, refplane is car bottom for example, all are millimeters, anyway it would be good if many of us could do all these measurements and few more if possible, we could put that to some knonledgebase then which would be information that is almost impossible to come by from any books or manuals and still this information is valuable if planning improving handling or putting car to simulation. Should really take photos from measurements some day as that is only way to really tell how I have measured these and from there it would be easier to spot errors in methods so I could make better measurements, it is just bit difficult with only two hands.
This are is such that I think there will be forever something new to learn for me, also because my memory is what it is, sometimes I remember things clearly, only thing is that my memory picks part of one thing and other part from 2nd thing without me realizing, so there always can be errors, just a word of warning if anyone has managed to read this far

Code: Select all

2-5	Scrub
70	trail
185	tire top to inner arch when car is lifted
200	front refplane
205	rear refplane
105	steering arm length
340	effective leverage arb
80	lower balljoint from ground height
320	steering arm to steering rack distance
320	lower arm pivot to lower balljoint distance
215	lower arm pivot height from ground
250	steering arm inside end height from ground
220	steering arm outside end height from ground
115	lower ball joint to wheel hub
245	compressed spring
235	arb link to strut
8	worn brake disc
250-280	strut below spring length
200	strut center to top of brakedisc
215	strut top to bearing cup
1045	strut top to strut top distance
15	strut top cover diameter
140	strut tilted back from vertical
590	strut length
67	strut top above tower
800-802	strut top from front light
450	rearward lower arm length
250	rearward lower arm inner point from front lower arm inner point
210	rearward lower arm height from ground
625	lower front arm pivots from each other
670	steering arm inner end to inner end
1220	steering balljoints from each other
1350	bdisc to bdisc, front
120	steering balljoint from center of wheel
150	contact patch width
40	tire's upper sidewall from inner wheel arch when car lifted along x-axis
130	tire contact patch length
47	tire upper sidewall from inner wheel arch when car resting on ground along x-axis
1346	front track from front of tires
1365	front track from rear of tires
59	width rear leaf
9	thick rear leaf
1250	length rear leaf

Well, hopefully some of this has some help to someone, suspension stuff is not overly difficult once one get hang of it, but there are things that tend to be bit taunting, like when one is going to change suspension arms, that is bit more of work as it is all 3 axles that affect to same things and you get different traits and feats with each, almost anything still works somehow, but to get desired result it is going to be bit of challenge, 1mm off is going to have already some effects so building too is not going to be very easy.

Anyway to get more camber to front one has to somehow get lower balljoint to go outwards more, it is very tiny what one can gain with moving strut top, so only way I know is to move lower balljoint outwards and there is few ways to do it, balljoint itself can be changed or lower arm or crossmember, then there is changes in other geometry too which one would like to avoid is plan is to change only camber, well that dependecy is what makes stuff quite fun as challenging, but it is not really so difficult at what it first may seem and there will be results from all that work.

Still it leaves problem with low amount of bump travel, but one can work around of that by accepting higher ride height and dealing rolling with other methods, that is easier to achieve than making new front of the car as to get more bump travel one would need to move strut tops, move inner wheel arches, design new front suspension mounting points etc. At least I don't think there is easier way to do it, surely making damper piston arm or coil over setup is not going to be enough as wheel arches come to way and lower arm motion range is designed to only so much upwards.

With all that it should be possible to make best out from 300 for sure, don't know if it will then still be quite what wanted, but it is a lot further from standard 300 and probably outperforming most other cars on road, might be bit overkill though

[jtbo]

Chris, I think that one of best improvements to handling might also be upgrading rear springs and dampers.

If I'm not horribly mistaken from front/rear weight ratio, I get natural frequencies of 1.53Hz front and 1.10Hz rear, 360GL.
This of course adds to understeering together with front riding on bumpstops when cornering, effictively increasing spring rate and of course natural frequency. I have no bumpstops (those rubber pieces at damper piston) here so that I could measure and calculate them (I forgot to add those when changed front dampers and managed to loose them) so I can't really tell how much their effect is, but from my memory they are around 50mm long and compress quite easily, maybe starting to add up when there is 40mm bump travel?

GLT rear springs were different too I think? Would need thickness and width of those to know if they are any different. I know front springs, with those I get 1.56Hz to front. If rear springs are same, but used blocks, then it would be just bit of worse, haven't checked v*dis for partnumbers yet.

This all is of course related to rFactor, but it really is same physics in play, this is my learning to understand it better thread about it:
http://www.nogripracing.com/forum/showt ... p?t=278913

You can use this for calculating such, if there would be adjustable dampers with them tested at shock dyno you could even know are you under or overdamped for springs and weights. Unsprung weight is btw not too accurate, should really get over with it and measure that too, well rear axle is something I'm not going to take off.
http://jtbo.pp.fi/tiedostot/rfactor/all ... _volvo.zip

Anyway armed with that and doing actual corner weighting of car it should be no problem to address most of handling issues, well if you can get adjustable dampers that actually are in correct range, allowing enough adjustment for bump and rebound so that one can actually get setup right.

I would think that cutting bumpstops to half, adding stronger springs that have offer same ride height to front and getting 2nd leaf to rear, preferrably not so strong as main leaf is, also having matching dampers to that setup and it should handle really nicely, add camber + better rubber and you should have a cornering machine.

There is however no guarantee, but one thing is sure, with standard bumpstops + lowering and standard rear springs it will understeer, a lot and only power can overcome understeer or in case of open diff spin inner rear wildly

Maybe some of help for someone.

[Evoman]

That was very interesting! Alot to take in though, so thats 1 person that read it all Those measurments might be useful for me later. Im keen to make the car handle better too

[jtbo]

That was very interesting! Alot to take in though, so thats 1 person that read it all Those measurments might be useful for me later. Im keen to make the car handle better too

I just checked green books and according to them all springs for B200 models have same rate, but length is different, my GLT aftermarket springs were mentioned to be bit stiffer and bit lower, but when I do numbers I get 26010N/m for aftermarket and 28304N/m for greenbook springs.

Also my car's rear leafs are 59mm wide, when green book states 60mm, maybe they shrink when they get old?

With greenbook values I get 1.63Hz front and 1.12Hz Rear when 56% of weight is at front, with 53% of weight at front I get 1.68Hz front and 1.08Hz rear, now weight distribution is between those two, I'm pretty sure of that, but I really can't tell for sure, anyway that has not too much of impact to fact that rear is super soft compared to front.

Also disclaimer, everything can be off by a mile

Those modern FWD cars are indeed bit funny, they have 1.3-1.4Hz at front and 1.5-1.6Hz at rear, putting such ratio to our cars would make them quite difficult to drive, spin at every roundabout or so, but surely that would drift a lot

There is still a lot to learn for me too, but basic idea is something quite clear, there is of course real world limitations then, when you compute something you can get perfect values, in reality you have to make compromises, but knowing this all helps making right choices at least if nothing else.

Basic idea is that when you have lower natural frequency at rear it is understeer and when lower is front that is oversteer, but there are more to it than that, bumpstops, dampers, wheel aligment and antirollbars all affect to it, but spring ratio front/back is foundation where I think one should start to build.
With enough of engine power and welded diff it is however perfectly possible to overcome this understeering character, however it still is there lurking and trying to surprise, but yes, with lot of power one likes to have understeering as it is easier to use that power then, not the fastest way though.

Those are points that I think might help too when learning stuff

edit: Oh yes, sorry about odd units for springrates, that is because rFactor uses SI units, but in realworld we use LBS/in or Kg/cm^2 etc, try to find conversion from http://www.convertunits.com/ might be for /mm but multiply by 1000 to get /m etc.