B4 hooking on carpet

[stuey]

Hi Darren, its no offence to your carpet mate. I have often had trouble with my cars like this at your place, my fault for not getting on top of it. I might try front rims with no tyres, should knock the grip back a bit!

[discostu]

Originally Posted by stuey

Back again I'm afraid. I may have mis-diagnosed the problem a bit last time. On a fast sweeping corner, it looks like the front inside wheel is lifting as the back end is collapsing. The rear end then breaks away, which may have been why I thought it was hooking. It still has too much low speed steering, but I think i need to take the inner row of spikes off the front. I started on the following setup, which was similar to my first one I tried. (Sorry I didnt have a chance to try your one Richard).
Front:
middle on tower, outer wishbone, link 1A, 1 washer under ball
steering 30deg trailing
shock blue spring 35wt no.2 piston

Rear:
inner on tower, outer wishbone, link 1b, 1 washer under ball
2 deg anti squat, short wheelbase
shock silver spring 30wt no.1 piston

basically Lee Martins Petit carpet setup. except I didnt get a chance to change rear piston to no.2

yellow minipins outer row off

I tried removing the washer under the rear ball to stiffen the roll, no real help. Put it back, put 35wt oil in rear to try and stiffen a bit, no real help.
Added another washer to front link to try and equalise roll front to rear, and put blue springs on rear to try and stop it collapsing, helped a little but reduced rear grip a bit.
I have a feeling the car may have been diffing out from something I read on here, how much spin should it have if spinning a wheel by hand?
The carpet is very grippy, would a soft rear roll bar help keep the rear end flatter through the corner and stop it collapsing?
Thanks for looking

change the rear piston will prob help as number 2 has smaller hole

[PaulRotheram]

If its a case of the grip being very high then the front pins may well be causing the main problem.

options are as follows..

Definately change the rear piston, then the base set up is correct, the main changes you should need to change to improove things for your style are springs, oil, shock position wheel base and anti squat.

However if the springs and general locations are right I wouldnt worry about the rest if your not racing competitvely yet.

As Darren said, ask Kev for help, if he is your local fast guy then thats the best way. 'Most' top end drivers have experience with the B4 in one way or another and can provide general help, however ask drivers who run the b4 for more specific advice.

Tyres are a huge part of set up (about 90%), if they are not right then the car will be wrong.
If your running pins all round, try spikes on the front, or even try stagger ribs as they provide grip without the 'snap' effect, meaning the car will be safe and easier to chuck around.

Asking for help trackside is important, local fast guys know what works well, and will be more than approachable.

[stuey]

Thanks guys. As you say, the no.2 piston should help too, with that bit more pack. Gonna try taking a couple of rows off the front tyres inside and out, and maybe a soft rear roll bar if the no.2 piston doesnt support the rear better.

[Spencer Mulcahy]

Originally Posted by Richard Lowe

It sounds like the whole car is too stiff in general, and the front overdamped. Instead of the car leaning into the suspension on the outside it's lifting the inside and running out of droop on the back.

I've been playing about with B4 setups recently, trying different running weight and softening/stiffening the shocks as appropriate and think I've now found my lipo setup

You should be on pins all round, staggers on the front are for wimps

I've not done a setup sheet yet, but I'll list how my car is now so you can try it...

Front
35w/No2/Silver, middle on tower, outer on arm, 24mm ride height, no droop washers
Camberlink 1-A, 2 washers on the tower, -1 camber
30 degree caster, in-line axles spaced middle, 2 bumpsteer washers on steering block

Rear
25w/No1/Silver, inner on tower and arm, 24mm ride height, no droop washers
Camberlink 1-B, 1 washer on U brace, -1.5 camber
2 degrees squat, medium wheelbase

Weight-wise I'm running the Trishbits front bulkhead and brace (55g total), and the older style Trish squat block (28g). Cells are the Trakpower Dark 5000 40c (284g).

Setup like that the car has been fantastic on every track I've taken it to, carpet/grass/astro it's been great. I do seem to be Mr Steering though so if you want to calm it down a touch the trailing axles will dull down the initial turn-in and moving the rear shocks to the middle on the tower will make the car square up quicker and give you a bit more rear end grip coming out

If anyone wants a setup for there B4 I would strongly advise this one. I ran it today at Bury and the car was the best that it has ever been so easy to drive the steering was fantastic it jumped fantastic, just wish I had this setup at the start of this year. Cheers Rich

[stuey]

Think I have worked this one out now, and feel a bit of a plank. Despite virtually any setup changes I made, the problem never really went away. I am using JC wheels, and tried taking the inside and outside rows off the fronts. I had another pair of fronts on Associated wheels which only had the middle 4 rows left, from ages ago. I tried these in the second round, rather than trim the originals down more. Imagine my surprise when the car went from a difficult hooky snappy monster, to a slightly understeery very stable car! Apart from the slightly wider wheels, the only difference is the Associated wheels have got a decent insert, where the originals feel like they have hardly anything in them! The tyre wall must have been collapsing and making it very unpredictable. Just to try, I trimmed them down to the same as the other wheels, and the monster was back, but not quite as bad. The moral is, dont use crappy old inserts you find lying around

[petemid8]

Do you think hard inserts are the way to go then? Like schumacher blue?

[PaulRotheram]

Id not advise the schumacher blue foams, they break up in to dust pretty quickly!

The medium 'snee' foams are the ticket, they can be re used many times and can survive acetone soaks!

I think what Stuey has found is that using older foams were his problem, reason being as it wasnt filling the tyre carcas and keeping the tyre firm through corners.

[stuey]

Yep, I probably used some old ones that probably dont fill the tyre properly. This has made the tyre too soft and flexible, making the handling very difficult when the tyre was deforming. I have been advised to try Schumacher green medium inserts, and a rear insert cut in half is enough for a 2wd front tyre.

[Richard Lowe]

Originally Posted by Spencer Mulcahy

If anyone wants a setup for there B4 I would strongly advise this one. I ran it today at Bury and the car was the best that it has ever been so easy to drive the steering was fantastic it jumped fantastic, just wish I had this setup at the start of this year. Cheers Rich

[sime46]

+1 for that set up. I ran my b4 for the first time in 3years and ran this setup. Our carpet is low grip and I was on well worn tyres. I went up to blues on the front and the car was brilliant! Thanks to Richard for the info. I was amazed how quick and easy the car was to drive. Can't wait to try it at worksop. It's gonna be awesome. Thanks again.

[stuey]

Raced again last night, hooking/snapping problem solved. I stuffed a whole rear schumi green insert in the front, bit over the top but I didnt want it too soft. Apart from being a bit scary on new tyres, it was fine
Might try some expanding builders foam next time... only kidding!