BJ4WE and total lack of balance

[RogerM]

Right then, before I make a choice between the for sale section or encasing the car in a block of concrete I want to make sure I am not missing a trick!!!

The BJ4WE seems to be a total piglet .... absolutely without balance in any way shape or form!!! The only place I have got it anywhere close to how I want it has been indoors on carpet and then it was passable at best!!!

The problem is a lack of balance, if you have front end grip you don't have rear and vice versa.

At kiddy I just couldn't get the nose into the corners without having the rear set so that you couldn't carry any throttle through the corners let alone adjust trottle mid corner.

At Coventry today I had absolutely no traction or sidebite at all and trying to set the car soft to help traction and sidebite it became really random (rolling about too much). I then stiffened the car back up and although it was much easier to drive it was a full second a lap SLOWER than when it was soft. Ok, it was consistently slow and much easier to drive but at least 1 second a lap slower than before (The top of the A went quicker than they had done all day so th track hadn't given out).

I've tried Richard Lowe's set-ups and working around those but they have FAR too much high speed understeer for my tastes.

I am convinced it is a combination of the rear inner link position not being outboard enough of the lower hinge pin and the fact the weight is too far back. Both of these will lead to the collapsing of the rear end.

My question is what have people done to deal with this this .... other than the S4 conversion obviously??

I have a couple more runs this year with the car and want to make sure I use them wisely. I don't mind rubbish placings due to constantly changing the car during the winter, all part of learning your way round a new car. The only problem is that I am going to have to do this with the 2wd too so have to move onto that in the new year.

If anybody can help I'd be greatful, if not I'm going to have to chance chassis.

[bert digler]

Right then, before I make a choice between the for sale section or encasing the car in a block of concrete I want to make sure I am not missing a trick!!!

The BJ4WE seems to be a total piglet .... absolutely without balance in any way shape or form!!! The only place I have got it anywhere close to how I want it has been indoors on carpet and then it was passable at best!!!

The problem is a lack of balance, if you have front end grip you don't have rear and vice versa.

At kiddy I just couldn't get the nose into the corners without having the rear set so that you couldn't carry any throttle through the corners let alone adjust trottle mid corner.

At Coventry today I had absolutely no traction or sidebite at all and trying to set the car soft to help traction and sidebite it became really random (rolling about too much). I then stiffened the car back up and although it was much easier to drive it was a full second a lap SLOWER than when it was soft. Ok, it was consistently slow and much easier to drive but at least 1 second a lap slower than before (The top of the A went quicker than they had done all day so th track hadn't given out).

I've tried Richard Lowe's set-ups and working around those but they have FAR too much high speed understeer for my tastes.

I am convinced it is a combination of the rear inner link position not being outboard enough of the lower hinge pin and the fact the weight is too far back. Both of these will lead to the collapsing of the rear end.

My question is what have people done to deal with this this .... other than the S4 conversion obviously??

I have a couple more runs this year with the car and want to make sure I use them wisely. I don't mind rubbish placings due to constantly changing the car during the winter, all part of learning your way round a new car. The only problem is that I am going to have to do this with the 2wd too so have to move onto that in the new year.

If anybody can help I'd be greatful, if not I'm going to have to chance chassis.

what tyres AND insert did you use

[RogerM]

Should point out I've been through .....

all rear link positions (1-3 washers as I can't get 4 in and rely on the nylock nuts)
both standard anti-squat settings .. and a bit of shimming
EVER Associated rear spring
Lots of oil changes

Smae at the front except I've not tried the longer link at the front as yet .... only so many runs in a day!

[RogerM]

what tyres AND insert did you use

Whatever is most appropriate on tyres and always use the DC Racing light blue inserts (same as the snee ones)

Trust me, it's not a tyre issue as I've tried "interesting" choices too.

[bert digler]

Should point out I've been through .....

all rear link positions (1-3 washers as I can't get 4 in and rely on the nylock nuts)
both standard anti-squat settings .. and a bit of shimming
EVER Associated rear spring
Lots of oil changes

Smae at the front except I've not tried the longer link at the front as yet .... only so many runs in a day!

lifting the rear brace does help why i dont know but it does by placing two washer between chassis and block

[bert digler]

Whatever is most appropriate on tyres and always use the DC Racing light blue inserts (same as the snee ones)

Trust me, it's not a tyre issue as I've tried "interesting" choices too.

fresh ballistic pinks or blues

[bert digler]

fresh ballistic pinks or blues

sorry greens not blues

[bert digler]

http://users.pandora.be/elvo/

[RogerM]

Fresh pinks today ... greens might have been a little more consistent but I had enough trouble with one set of tyres and glue in the cold.

I've seen that guide, it's very good.

Should point out that I've been racing since the mid 80's and car set-up generally isn't a problem.

I do however need a car that you can lean on and carry lots of corner speed that will stand throttle adjustment mid corner. Too many years running a Predator in RRCi stock class to change now!

[bert digler]

Fresh pinks today ... greens might have been a little more consistent but I had enough trouble with one set of tyres and glue in the cold.

I've seen that guide, it's very good.

Should point out that I've been racing since the mid 80's and car set-up generally isn't a problem.

I do however need a car that you can lean on and carry lots of corner speed that will stand throttle adjustment mid corner. Too many years running a Predator in RRCi stock class to change now!

ive been racing 20 years and newer cars dont seem as forgiving as older ones i must admit my favourite car of all time was the cat xls just awesome in its day

[PaulRotheram]

I'll offer more help tommorrow as right now im currently completely exhausted from today. But one thing i noticed you say:

I've tried Richard Lowe's set-ups and working around those but they have FAR too much high speed understeer for my tastes.

I've tried richards car, and it is anything but how you have described. Infact richards car has the most steering i've ever experienced.. and very balanced. Something doesn't sound right..

[bert digler]

I'll offer more help tommorrow as right now im currently completely exhausted from today. But one thing i noticed you say:



I've tried richards car, and it is anything but how you have described. Infact richards car has the most steering i've ever experienced.. and very balanced. Something doesn't sound right..

the astro track at coventry is an absolute pig to drive in the wet it has no traction at all on the flipside its grippy as hell in the dry

[RogerM]

Fairysnuff .... look forward to your input.
My car is pushing like a mother to be of quaduplets on Richard's Set-ups!!!!

[Lee]

How many washers are you running under the ball stud on the front camber link? reducing this makes the car more positive, as said above you must be missing something? are you running a 1 way?

I run the same as rich, give or take a shim here and there, the car is always positive.

Silver springs all round , 30 wt blue piston rear and red 35wt front.

3 shims under rear camber link, 1 at front, std squat, outside on all wishbones and middle of towers. Always run a 1 way!!;)

[RogerM]

Front is 1 shim under and outer hole, rear is 3 under

I run a 1-way on the shaft .... never been a fan of them in the diff ... find having it on the shaft is much smoother to drive.

Interesting you say outside holes in the wishbones .... most of the set-ups I've seen have been using the inner hole on the front and all are inner on the rear. That might be the problem right there!!! Been thinking that there is a bit too much balance in the droop front to rear, usually prefer a car with less front droop than rear. My next step was going to be limiting the front by about 3-5mm in terms of the resultant droop.

Need to find somewhere to test over the next couple of weeks!!!!

[Lee]

In side holes on the front make it very random and snatchy and as you say increase droop which would give more lift on power and more weight transfer to the rear, and on power understeer;)

[RogerM]

that is what I would ahve thought but so many people seem to be running that location I slavishly followed .... fool that I am!!!

Right then, first change!

[matdodd]

I allways ran the inside holes on the xx4 but since going to the S4 have stayed on the outside hole on the front & inside on the rear on most tracks, it just seams to let you push much harder like that!

[Chris Doughty]

incoming spanner....

obviously my experience is from the S4 but I believe this option is universal between the 2.

front shock location on wishbone...

outside is safe and has mid-corner push.
inside keeps the car hooked up in the middle of the turn.

keeping the droop the same between these settings keeps similar on power steering, I find that letting the front droop more give you MORE on power response. (this is when using a one-way-diff. I never use anything different)

so I find if I want to make the car drive more from the front on-power I give it a slight bit more droop on the front than the rear.

typically I use axles level with chassis as a base setting for droop all round, a touch more on the front if I want the drive from the front feel.

also - if Lowe runs a one-way-diff and you don't thats where your heavy push comes from, especially on power.
you could try and tighten up your front diff, but you might loose turn-in

[KyoshoK]

Q: how is all your electronics placed?

[RogerM]

Thanks Chris, what your saying is true of my previous cars and makes perfect sense! That was part of the reason I kept the inner mounting point on the front as the car just seems to push like mad anyway so anything I can do to help with mid corner / corner exit steering is seen as a help.

As for the one-way diff ...... if it is absolutely required I'm probably going to move the car on and go for something else .... I dislike them that much. It's partly the way they drive and partly the fact that they seem to destroy everything around them!

KyoshoK, my electrics are all on one side .... servo, LRP Comp TC brushless then spectrum reciever .... I tried to get it all on one side to balance the motor weight as much as I could ... could probably do with a few extra grams to even it out further I agree.

[RogerM]

I know that they are frowned upon by the 1/10th off-raod masses but I have always run anti-roll bars on everything from the Optima Mids through Preds to the car that I ran when I was last racing 1/10th O.R.

So .... question is ... how many people run them or have tried them and what do you think about the instalation of them on the BJ4WE???
I'm not worried if the standard bars are too thick or thin as afterall they are just a bent bit of piano wire .....

[markwilliamson2001]

Most don't tend to run them unless on very high grip AND smooth tracks (both front and rear) or on smooth low grip dirt tracks (rear only to assist steering mid-corner).

HTH
Mark
I don't tend to run them at all tbh on any buggy.

[Northy]

I don't even run the on them Pred these days.

G

[Chris Doughty]

try a tighter front diff and slightly looser rear diff then Roger, this might give what your looking for.

one-ways give very much a 'drive front the front' feel to the car, I would have thought you would have liked it?

[Richard Lowe]

Can you post your exact setup Roger?

As Lee has said already we almost never run on the inside hole of the front wishbone unless desperate for steering, on the outside the car is very consistent.

I've only managed to get the centre one-way to feel right at one event, and that was Tiverton on dirt so generally the centre one-way is a no no.

Another thing to look for is how aggresivly you are driving, the car really likes you to be gentle and controlled - sit back, drive at 90% and let it do the work, 'ragging it' just doesn't work.

Something else I have found is the car always feels 'loose' and moves around more than most other cars, when it's set up correctly and is fast you are almost in a permanent state of drift.


Paul - I remember when you had a go with my car at Southport, you almost needed a change of underpants first time you turned into a corner haha :D

[super__dan]

As an outsider to the BJ4;-

Firstly to echo Pauls comments, I too have never driven a car with so much on power(controlable) as Rich's. You say you're running Rich's setup but without a one way diff then surely you're not, and a pretty massive change it is too.

Other than that, Rich Coates car was consistantly a pig when he got it, no obvious reason. I think it was traced to a tweaked bit of blue on it somewhere and more importantly a mis functioning centre one way, but I forget what or why but when he went to full time 4wd, he was instantly a country mile faster. Now he likes the car he's on a one way diff and was second at Worksop yesterday I think.

[Richard Lowe]

Dan, Rich's centre one way was broken and wasn't getting drive half the time, we removed it and the car improved but was still rubbish. When I rebuilt the car for him the back end was tweaked for some reason, I put it back together using the same parts and it was fine again :confused:

I blame the origonal owner, wonder who that was :p

[RogerM]

Can you post your exact setup Roger?

Been using your Bury starting set-up as a base but have been up and down upto 2 spring grades at both ends (keeping a balance and also biasing one end by one grade). Also run links from the longest to the shortest (as your Bury set-up). I might have mis-read the sheet but it still looks like it's on the inner hole to me! Car always feels poor no matter whatTBH.

As Lee has said already we almost never run on the inside hole of the front wishbone unless desperate for steering, on the outside the car is very consistent.

Been REALLY desperate for steerign on ever run .... the sliding back end I can live with ... so long as the front isn't pushing hard at the same time which has been the case.

I've only managed to get the centre one-way to feel right at one event, and that was Tiverton on dirt so generally the centre one-way is a no no.

I am really not a fan of front one-ways, not even a little bit as I find they make the car inconsistent as you modulate the throttle to control turn radius and absolutely unpredictable when you have to shut the throttle mid corner (say to avoid somebody having their own accident). Not really keen on spending big bucks on something that I will probably use once and then leave in the box so unless somebody has one I can borrow to try it's unlikely to happen.

Another thing to look for is how aggresivly you are driving, the car really likes you to be gentle and controlled - sit back, drive at 90% and let it do the work, 'ragging it' just doesn't work.

I'm an old stock racer and thus I try to keep as much corner speed as possible and be gentle on the sticks (couldn't afford to scrub off speed as you didn't have any power!). In fact when I have a car to my liking I only really use full lock in low speed hairpins and to get out of sticky spots. Most people can't drive my cars as they need such a light touch.

Something else I have found is the car always feels 'loose' and moves around more than most other cars, when it's set up correctly and is fast you are almost in a permanent state of drift.

That is fine by me, rather that than it grip rolling and snatching about!!

Paul - I remember when you had a go with my car at Southport, you almost needed a change of underpants first time you turned into a corner haha :D




I am greatful for any help offered at the moment as I am currently of the opinion that nothing other than a re-engineering job to move a fair chunk of the weight forward is going to help. If that is the case I'd probably try a different chassis as I just don't have anywhere to test without driving for around 1.5 hours plus due to living in racing no-mans-land ... Cheltenham.

Any further suggestions (other than fitting a one way diff)????

[RogerM]

try a tighter front diff and slightly looser rear diff then Roger, this might give what your looking for.

one-ways give very much a 'drive front the front' feel to the car, I would have thought you would have liked it?

Chris,

front diff is much tighter than the rear (but still working nicely if you knwo what I mean). Rear diff is just on the limit of slipping on high grip stuff!!!

I have never really got on with one-way diffs. They are probably managable if your in a heat where your not likely to have to drive around others but even when I was racing before as an F2 I always seemed to be seeded low (....think StuW was trying to tell me something :rolleyes:)

More than anything (other than the price) the fact that the S4 has to run a one-way diff or full time 4wd is what put me off going that route!!

I do like the drive from the front feel but it has to come from the chassis. I so nearly got the Pred again when coming back into the sport but the lack of support troubled me.

Thanks for the suggestions by the way.

[gordy]

You'll have somewhere to try it out soon Roger. We're building a 10th off road track at Ledbury, next to our rally cross track. And if you are getting rid of the BJ4, fire it in my direction!!

[Lee]

Sorry roger, one way`s are the future,

You can even use the brakes when using the 1 way in the BJ4, it is very consistant, lots of high and low speed turn in, its just so easy to drive.

Stick with it, possibly ask rich or myself for a go if were about and see how ours compare

[matdodd]

Most people do run oneway diffs now Rog, the only people I can think of that dont are Yardy & Daz! It might be worth taking a look at Yardys D4 setup.

From past experiance when ive gone from a good setup with a oneway diff to the same setup with a diff in the front its understeer city :(
If I was you id try Rich's setup to the letter, it allways looks good

[Richard Lowe]

I'll have to put the final 'magic' setup up in the setups thread, it's almost as the Bury setup but with a few tweaks here and there that make it more consistent.

You also said you only had 3 washers under the rear camber link, try to get some longer Losi Ti ballstuds and get 4 under there, it makes a big difference!

Don't be scared of the one-way diff, if you have a go with either Lee's or my cars you will be amazed how consistent and balanced they are :D

Are you going to the indoor finals? If you are and still having trouble by then throw the car on my table on Sat and I'll give it a going over for the Sunday ;)

:::EDIT::: - I've just had a look back at the Bury setup, copy it exactly but goto the outside hole on the front wishbone and medium wheelbase ;)
Run the rear as wishbones level and the front slightly lower.

[Gaz_Stanton]

How about something like this to cure your handling probs Roger... :D :p
http://www.oople.com/rc/photos/mako/imagepages/mako10.html

[matdodd]

Like what Gaz?

[RogerM]

How about something like this to cure your handling probs Roger... :D :p
http://www.oople.com/rc/photos/mako/imagepages/mako10.html

Still bar far the best handling car I have ever had the good fortune to own!!!! Don't think I would have held my F2 that last year with anything else!!!

She had so much front end grip you just didn't need the front one-way, ran quick even with permenant 4wd. You ran yours with a one-way diff didn't you (it's sitting on the desk in front of me as I type), must have been crazy!!!

Anyway back on topic!

[RogerM]

My memories of one-way diffs are;

R1 broken front driveshaft
R2 broken other front driveshaft
R3 broken transmission
R4 broken everything as you drive like a donkey as you can't get anything with just one round anyway.

:(

On top of that there is the cost issue;

£60 for the one-way diff
£12.50 for the Shiny CVDs (so they stand some chance of lasting)
£5 for the springs to keep the outdrives in the one-way unit

£77.50 is a hell of a lot to throw at an 'upgrade' that may not suit me.

If the BJ4 does require a front one-way diff to make it work then I guess it's going to see big changes (or an Ebay listing).

Richard, thanks for the offer of help. If I am at the indoor finals with the BJ4 I'll take you up on that kind offer.

Time is running out however as I have to get a 2wd somewhere close before the start of teh season too.....

[delanobe]

Somebody has the article code of the long Losi ball studs (I need them for the 4 washers under the rear camber link).

When you say "short camber link", what does this mean exactly? :confused: Still learning! :rolleyes:

Thanks!

[Lee]

roger, i only use the one way, i dont use the springs in it or the shiny CVD`s, my car is totally standard:D

[super__dan]

Roger

You’re asking for help, everyone that is quick is saying use a one way diff and no-body has any issues with using it. So it’s either don’t buy one and have an apparently slow car that doesn’t suit you, or buy a one way and have a fast car that doesn’t suit you! ;)

You’re right about the cost, but everyone I race know and race with (not just F1’s now but all the lads I know) uses one in a range of cars (XX4, X5 and BJ4’s primarily though). My shiney front CVD’s have been in since the indoor finals so have done a whole season and though a little worn, they won’t be changed anytime soon.

[Southwell]

I didn't like the one way to start off with but after a couple of meetings the car started feeling so much better. I don't think i would go back to a diff.

[RogerM]

First of all I must thank everybody for all the thoughts, ideas and information. It is greatly appreciated.

Lee,

are the standard (non shiney) CVD's holding up ok??? I've been told by most people that they don't last long and should be changed out at the time of fitting a one-way diff. It's interesting if you think they (the kit black ones) are ok on your car


Dan,

I appreciate what your saying mate. My experience of them on several other cars (xxx4, Yok BCS) is that they don't suit me ..... I even ran non-oneway driveshafts on my old Procat!!! Shiney CVDs are supposed to be quite strong and wear resistant so I'm not suprised yours have lasted well.

Ian, my problem is that not only do I not like the snatchy way they drive (especially how they feel as you go on and off the throttle mid S-bend) but also my last experience of one was that I didn't finish a race all season due to a transmision failure, of some sort, in each and every run.



I think that the evidence is mounting ....... the car needs a one-way diff to perform well in the UK. I'm going to have to think about my options.

Out of interest has anybody had a BJ4WE go well with a centre one-way fitted or is it all doomed???

[Southwell]

Without actually seeing the car that seems like the slipper (or lack of) is putting too much stress on the tranny.

[Lee]

Roger,

Yes im using the Kit black ones, i have had the car since october 2006 and its been used indoors and out, including dusty/sandy/wet tracks so it had a fair bit of abuse and i only ran the diff for one meeting, so i have had the 1 way in for a year now. I have never even opened up the front diff casing or had the need to re-build/replace the driveshafts.

The BJ4 doesnt actually feel like its using a one way, it feels very neutral yet positive and never snatches.

All this may be because i drive like a touring car girl though:confused:

[Northy]

You’re right about the cost, but everyone I race know and race with (not just F1’s now but all the lads I know) uses one in a range of cars (XX4, X5 and BJ4’s primarily though

and an X11 on occasion..... :D

G

[tony6187]

HI I RAN A BJ4WE LAST SEASON AND TRIED ALL THE OPPTIONS(ONE WAY,CENTRE ONE WAY,DIFF) AND FOUND THE CAR EXTREMELY QUICK WITH THE ONE WAY BUT INCONSISTENT.WITH THE CENTRE ONEWAY THE CAR WAS QUICK AND EASIER TO DRIVE BUT I FOUND THE DIFF JUST AS QUICK AND FAR MORE CONSISTENT.HAVE SINCE SOLD THE CAR(GETTING B44) AND UNFORTUNEATLY DONT HAVE ANY OF MY SETUPS :(.SORRY CANT BE MORE HELP BUT I DID FIND THE CAR EXCELLENT.

[Richard Lowe]

I think that the evidence is mounting ....... the car needs a one-way diff to perform well in the UK. I'm going to have to think about my options.

Out of interest has anybody had a BJ4WE go well with a centre one-way fitted or is it all doomed???
You are better off running the car as kit with full time 4wd on our tracks than you are running the centre one way. The centre one way makes the car inconsistent on corner entry and gives lots of mid corner 'pivot', it seems to work well on broken up dirt/clay but thats about it.

You could always get the one way diff from *ahem* ebay *cough* ;)

Don't worry about reliability, the diff I have in the car now I've been using for so long I can't remember and have never had a non-finish caused by it. The front gears are indestructable and even the standard black CVD's are almost impossible to break, if you are unlucky they might bend without the outdrive springs - but you will finish the race :)

[PaulRotheram]

Funnily enough.. i have a front one way for the BJ4 WE.. it just needs the diff gear for it.

Could maybe come to a deal? :)

[RogerM]

Funnily enough.. i have a front one way for the BJ4 WE.. it just needs the diff gear for it.

Could maybe come to a deal? :)

Maybe we can Paul, please PM me.


Right then, I'm going to give one a try (assuming I can get one) as it seems most people are happy to run them. If I don't I guess I'll never know and as I say many times a day at work .... "Every day is a school day!!"

[RogerM]

You are better off running the car as kit with full time 4wd on our tracks than you are running the centre one way. The centre one way makes the car inconsistent on corner entry and gives lots of mid corner 'pivot', it seems to work well on broken up dirt/clay but thats about it.




That sounds very much like the problem I have with the car ...... leaves me only two options ...... will try the diff before trying a different car!!!:o

[thaking]

Roger!
take a look at my car, i`ve made a piece that lower your rear links about 6mm, this will balance your car i think, it worked for me......

[RogerM]

I have something very similar drawn up ready for manufacture. Thanks for sharing the idea with us though.

:)