Longer B4.1 Vega on the cheap!

MHeadling · #1 07-01-2012

Hi Guys, Just a quick one to show you how to do a +6mm wheelbase mod on the Vega B4.

I understand there is a new long chassis in the pipeline for the Vega B4 but this will be a good stop gap and costs next to nothing!

The pics do the talking really, but just attack the rear arms with a dremel and make sure the diff outdrives have clearence.

I measured back 6mm and made the cuts.

As you can see in the second shot I have spaced out the top of the shocks with some blue spacers to keep the shocks in line.

I am yet to run it but Mr Xtreme's car went well with this mod so sure I'll be on to a winner!

grelland · #2 26-01-2012

did you test this yet?

I just did the same mod, and will have a go on an indoor clay track this coming Sunday

MHeadling · #3 27-01-2012

No yet , been racing 4wd, I will test it next Thursday

DCM · #4 27-01-2012

The difference between that mod and a +6mm chassis, is I would assume the gearbox is also 6mm further back, affecting the weight distribution, by just extending the wheelbase, you have moved the CofG forward not rearward.

bigred5765 · #5 27-01-2012

what dcm has said is right, all you have done in move cg forward wont work the same as lengthening the chassis,
you have also altered the angel of the drive shafts compared to the diff position which will also alter your forward drive

MHeadling · #6 27-01-2012

Well this mod worked well on Mr Xtreme's Vega B4 so looking forward to trying it out.

With the Vega B4 you flip the rear arms giving quite an extreme drive shaft angle, the car has plenty of drive so will be interesting to see if I can get it a bit smoother with a little more rotation.

If it doesnt work I'll just put it back to normal!

grelland · #7 27-01-2012

that's part of the fun, isn't it; testing new ideas ?

Next weekend will be the first in the 2012 Nationals Series here in Norway, so I will test it this Sunday, and based on the results, and hopefully some feedback from your testing on Thursday, I will have plenty of chance to put it back before the race on Saturday.

As usual, it will be me, and not the car that is the limiting factor

colmo · #8 27-01-2012

The X Factory chaps know of a mod Brian Kinwald came up with that extends wheelbase on the front, not back. Sorry, can't find the link atm.

janus_77 · #9 27-01-2012

Quote:

Originally Posted by colmo

The X Factory chaps know of a mod Brian Kinwald came up with that extends wheelbase on the front, not back. Sorry, can't find the link atm.

http://www.oople.com/forums/showpost...8&postcount=23

http://www.oople.com/forums/showpost...1&postcount=26

Changing the wheelbase this much is rear could be a problem. You can loose a lot of "drive" this way. The angle of the driveshafts is underestimated my most. While it can be more important is most low grip situations than wheelbase imo.

MHeadling · #10 27-01-2012

Thanks Janus, if it's good enough for Mr Kinwald good enough for me!

It'll be an interesting to test the mod iv done to the wishbone, the driveshaft angle looks quite Xtreme compared to other cars so be good to try out.

I'm racing on carpet so have plenty of grip to play with

colmo · #11 27-01-2012

As regards the original mod, I recall Mark Penney describing a mod that was the exact opposite of this (i.e. shortening the wheelbase and moving the CoG backwards, on a B4) on a particularly rough dirt track in England (Tiverton, was it?) - combined with no anti-squat, it was the only way to improve forward drive. It stands to reason that this mod would do the opposite, making the car more agile in high grip situations, but shedding drive.

The BK mod does the opposite to the OP's mod, moving the CoG backwards. You could always do both...now that really would be a limo...!

MHeadling · #12 27-01-2012

Cheers for all the posts guys, some good set up info here in this thread.

Grelland let us know how you get on, I should be trying my one next Thursday

Tomboo_91 · #13 27-01-2012

Quote:

Originally Posted by janus_77

http://www.oople.com/forums/showpost...8&postcount=23

http://www.oople.com/forums/showpost...1&postcount=26

Changing the wheelbase this much is rear could be a problem. You can loose a lot of "drive" this way. The angle of the driveshafts is underestimated my most. While it can be more important is most low grip situations than wheelbase imo.

Funny enough I played with this yesterday. The only thing I couldn't get right was the steeringrack-plate-thing to keep the same ackermann. Moving the rack forward would make it touch your topplate and shocks. Did you make any changes to it?

I also took a small slice off the steeringblocks underside. So I'm still able to run the steeringblock in it's lowest position.

janus_77 · #14 28-01-2012

Quote:

Originally Posted by Tomboo_91

Funny enough I played with this yesterday. The only thing I couldn't get right was the steeringrack-plate-thing to keep the same ackermann. Moving the rack forward would make it touch your topplate and shocks. Did you make any changes to it?

I also took a small slice off the steeringblocks underside. So I'm still able to run the steeringblock in it's lowest position.

I don't like the std. Ackerman anyway

, so I really didn't bother with it that much.

With inlines shimmed forward I just use the rear hole of the steeringrack and if I use traling with a cut casterblock I use the front hole in the steeringrack. But I'm on inlines shimmed forward about 96.8% of the time.

But to keep the same mechanical Ackerman. You can flip the steeringrack and cut-off the (now) front hole, since it will be rubbing the bulkhead badly. This way you can test and see if you like this setup.
But if you like it, I would strongly advise to make an alu. steeringrack plate. Since it takes a lot of material way of the rack. But its something I've not tried, but its a viable solution.
If your just trying to keep the same "feel" I just would re-adjust your Expo on your transmitter.

On it rubbing shocks, it should be close. But if its really rubbing, you could move the shocktower forward by putting 2 ~ 3 mm shims between the shocktower and bulkhead.
I always use this, but I do it to keep the shocks in the same angle as the arms.
When you keep having problems rubbing your just triing to get some extra steeringlock out of the car

. Just shave a bit off the shock location in the arm, so you van shim it forward just slightly. That combined with a moved shocktower gets the shock/arm angle back in the std. position

I allways run the steeringblock low, since you moving your pivot point higher up the hingepin on the arm, that makes the height of your wheelaxle higher than normal anyway. So I want to keep the steeringblock as low as possible.
But rather than cutting the steeringblock, I prefer cutting the arm. I've never had it break in that point even when it has been lowered

Hope this all made any sense......