Cookie200sx

Did you move the spring over to the new outdrives?

trf211

My base setup for sdrc.

18mm, +2 axle and diff height, kit springs kit pistons kit eyelets, 32.5wt front 30wt rear, 5° caster, +1 HT steering, center center C/D, shock positions front-2C, shock position rear-2A, rear camber link-1mm carbon plate on hub/1mm on ballstud on hub/3mm on tower(position 2).

RogerM

No issue with the rear bar, a 0.2 step change gave a similar handling change to what I would have expected changing 0.2 step on the B6. To be fair I haven't messed with it much other than going +/-0.2 to see how it reacts, the 1.2mm kit bar seems to be the sweet spot for the tracks I've been running on.


This is interesting, I've not noticed any issues and I have 2 ball diffs running, one built from parts like yours and one from a B7D kit. Both felt exactly the same to build, ran in at the same rate and did the usual set it once and leave it alone for months reliability of setting.
The one built from parts has a non-caged thrust bearing along with being set medium-tight (1.25 revs on the 180deg flick test) and has done around 40 packs of running, the B7D kit diff is absolutely as kit including the caged thrust race some people have struggled with set loose (1.75 revs on the 180deg flick test) and that has done about 10 packs.

Running both cars again tomorrow, weather playing ball of course, so will feedback if I notice anything strange with them.


If you are really concerned pick up a set of B6 69mm driveshaft bones and use the B6 outdrives. I have tried this back-back with a B7 ball diff and from what I could tell there was 'maybe' a little more grip with the B7 diff than the B6 diff set to the same (on the highly scientific flick test) but it is hard to tell so I'd be happy running either setup on astro.

RogerM

I've cut your post down to just the bits I want to reply to.

I have found something similar with the springs, the whole car is so nicely balanced that I feel that will be a rule of thumb in as much as not going out of step by more than +/-1 grade. Grey/White seems like the perfect balance in low grip and yellow V2 / yellow V2 seems to be spot on in high grip. If I end up on Blue / Grey tomorrow on dry astro I won't be at all surprised, although I suspect something more like Yellow / Blue might be the end point.

Again I've found the same with oils, no longer are we having to slow one end of the car to help the other. On low grip I ended up on 32.5/27.5 using 2x1.8 +1x1.1 & 1x1.8/1x1.9 + 1.1 pistons. Even in the dry tomorrow I expect to only be going up 2.5wt all round based on what I've learned of the car so far. Can really let the shocks do their job of keeping the wheels in contact with the track surface and doing all the roll / pitch stiffness control with the geometry as it really should be, excellent :-)

I was talking to my friend who took the TQ at the meeting on Sunday who was running the B7 for the first time, I convinced him to turn his brakes down but add a bit of extra drag-brake at the end of practice. Wish I hadn't as before that I was faster LOL. Our best lap times both came when we had the brakes set so the car could flow more naturally through the corner (17.17 for him, 17.20 for me ... next best lap time was a 17.42 in that round).
It goes back to what I said before about driving the car smoothly and not beating on it giving the best result, glad you are finding the same thing on totally different surfaces.

Antisquat is very effective on this car, very. I ran pro-squat on the B6 on occassion and it kind of helped with weight transfer off the front in low grip but not hugely. Equally I would run more antisquat when I wanted rotation and/or popping jumps on higher grip but most of the time it was left at the stock 1deg as it wasn't a dramatic change.
On the B7 though it is a VERY noticeable change, as you have found 0.5 change makes a real difference.

If you haven't noticed I'm exceptionally happy with the way this car responds to adjustments and the fact there are no compromising band-aids needed :-)

NickMG

Roger, I found the problem with the diff. The brand new thrust race had destroyed itself while I was running it in on the bench. Fitted another and all is fine. I had begun to doubt myself before I found the answer. 🙂

BigBuckORamma

That is the same pill configuration i was running as well, based off of the Spencer Rivkin Setup. But i am convinced that worked on his setup, because he was running a Gear Diff at the time when he ran that at club racing at Hobby Action.

I am currently running .5 Down and In on the C, and 1 Down Middle on the D.

The slight tow in made a difference. And i ran back to back with .5 in middle, and it was better, but i would still lose traction and get loose on corner exit when the full power came in, when i switched to .5 in and down on the C, and that looseness was gone. Car was locked in on corner exit. It did have a little push. But it was "safer" that way, and i didnt have time to tinker further in Free Practice.

Next i will try .5 Down Mid in the C, and see how that compares to .5 Down and In. See if that allow the car to rotate a little easier and square up better in the 180's.

BigBuckORamma

It does not. They are shot in the same molds, which is where the problem is located.


I wish i had the time and the money to measure screw holes, and look inside the gearbox for witness marks on the molds, and be able to tell which witness marks apply to which mold, and find the transmission cases with the lease amount of slop in them. Because transmission fitment does seem to be more mold specific than just a result of plastic shrink rate, and handling during manufacturing.

trf211

Just to be clear I'll explain why I made some of these changes. The past month I started on the kit setup which was decent, in my opinion too soft on the front end and too stiff on the rear end. You can see this by people drilling the rear piston, I tried it(2x2.0, 2x1.9+1.2, 2x1.9+1.3, 2x1.9+1.4, 2x2.0+1.2) and the on throttle grip is way way better for sure but the pack starts becoming too low and low speed damping is too fast. This search for weight shift at low speeds is due to the leverage rate and shock speed of shock position B on the arm, it is just slightly too stiff spring rate and too fast of a shock shaft speed that pack kicks in too early. Shock position A on the arm doesn't require any modifications to the shock package(2x1.9h 30wt), low speed on throttle grip is phenominal and same with braking(instead of turning my throttle and brakes down when I built the buggy, I was now turning up punch and brakes). The rear is more likely to lift during braking on position B due to the stronger spring preload require to retain ride height, position A with its softer leverage rate and slower speed stays in contact with the track better.

Center center pills with the 1/1/3 camber link combination make the car feel 'in' the track vs ontop of it. You can drive it much harder at the limit on before it bites and wants to flip. The narrow pill setup feels tall and dumpy compared to center. Moving the upper shock location on the rear from 3 to 2 also settles the buggy into the track.

I'm an entire lap faster on that setup vs the box setup, I really recommend testing it out.

ChocoTaco73

iTrader: (5)

Guess I'll throw in my B7D experience from this weekend on its maiden voyage. I ran kit setup and found I only needed to move the battery forward maybe 4mm or so and the car was dialed. Granted, a few of the locals (Rainman's in Bakersfield) were changing the shock package to one similar to what BigBuck mentioned but I was trying to change as little as possible and concentrating on my driving since the car felt so good anyway. I'm very impressed, I brought my LD3 (w/B7 hubs) and box stock Mugen MSB1 along for the ride and after 1 pack I put my LD3 away (still need to fine tune w/the B7 hubs, probably would've been better with stock pieces) and the Mugen has potential but it was clear which one was closest to the mark. The B7 was easy to drive consistently quick, carried a lot of corner speed but would also rotate on a dime and power out of corners if I needed to. I was not a fan of the B6.4 but had high hopes for the B7 and it did not disappoint. Running 17.5 Reedy SP5, 31/72, hardwired fan w/duct, no issues with heat or lack of speed/punch. Not having a local track it may be a little while before another road trip to race again but I'm looking forward to tweaking the setup a bit and see how it responds.

76jimmy

iTrader: (28)

Finally got my b7 on a track for some practice laps. I haven't had a car on a track in almost a year so I had some rust to get off. Car felt great with fuzz rears, swaggers front on industrial carpet. I need more time on it to get comfortable as I was with my 6.4. I'm happy with it. I'm not as serious of a racer as I've been in the past. Glad I've got a solid buggy to hit a few track days with.

Rettich

So is it possible to use 12mm springs ob 13 mm shocks?
Or do u use 12mm shocks?

BigBuckORamma

Use the 12mm spring Shock Cups, and invert your adjustment ring, so the 12mm spring has a flush surface to sit against.

fat500

iTrader: (51)

On Dirt how do you guys like it

todb

iTrader: (68)

It's been very good on clay for me. I haven't been this confident in a buggy for a long time.

ChocoTaco73

iTrader: (5)

On wet clay this weekend the buggy was great, even the track was a bit slimy I never felt like i was lacking in traction. So much better than the B6.4!