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Schumacher
(http://www.oople.com/forums/forumdisplay.php?f=46)
SX REAR MOUNTED SHOCK MOD
In jimmy's report (and what a great report) there's photo's of si moss's car with the rear shocks mounted behind the rear shock tower.
1/ What benefit does this have ? 2/ Is it only for certain tracks ? 3/ Do you run different oil's, pistons, spring with the mod ? Thanks in advance :D |
Hey Ste, There is an easy way of doing this mod, all you need are four long screws, 2x M3 locknuts and something to shim the tower back further. If you remove the wishbones from the gearbox sides, and literally put them on the other side of the car (but remember to get toe in right).... this achieves rear mounting positions on the wishbone, while wheelbase being marginally shorter (2mm). Then mount the tower on the rear of the tower mount, but with some spacing (I used about 6-7mm by using 4x Losi pistons I had lay around) and use longer screws here. Then using long screws to mount the shocks, followed by 2x lock nuts (so the shocks are behind the tower and nut under it as with the std shock screws). The only thing to modify is the rear bumper, which needs to be cut narrow as the blocks now hang further back than they did. You may need more antisquat, as the wishbone on LWB binds on the blocks otherwise.
I have seen two other ways of doing this. One involves swapping wishbone but not blocks, and then modifying the wishbone - this acheives a very short wheelbase. The other way is leaving the wishbones alone and redrilling them - so nothing else on the car changes - just the shocks. The benefit, is when the wishbone flex's, because the shock is on the rear it is now the front of the wishbone which flex's and this helps the car drive very bumpy tracks such as Talywain - this is where it was tried and was found to be good. It was done for a certain track, but this mod will give benefits on all tracks... as it also moves weight rearwards which I believe the car needs. it also does other things (depending on which way you do the mod, there are 3 ways of achieving the rear mounted shock). but the way most have done this, makes the car shorter, and the angle of the driveshafts creates better forward traction. I would not change the setup for the initial try. Shouldn't need to be any different. Ste, PM me your email address, I will email you some photos tomorrow of how mine looks. |
Good stuff Chris - I was just told 'its better over the bumps boss' - but you actually explained it all! :thumbsup:
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any images? :blush:
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hi chris, a quick question. Do you not run the roll bar on the back of your car? I'm assuming that with the wishbones turned round you can't use it any more.
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Mossy tried what Chris has said and yes the idea was to make the car better over bumpy sections. But at Ozfest he put the whish bones the correct way and just left the shocks at the back, The Team are just testing little tweaks here and there to fine tune the rear end a little. So Mossy did run the rear roll bar at Ozfest.
You will also notice that that he is running the car a little harder too (Grey springs) Tony |
Yeh to mount the rear roll bar, you will need to drill holes in wishbone for the way I have explained.
Some people have only swapped wishbones, not the blocks, but then file 3-4mm off the back otherwise the car is mega_short.com. I think Mossy has left wishbones alone but then drilled new holes for the shocks on rear of wishbone, so nothing other than shocks has changed. Apparently the method above gives better forward traction than this due to swept forward driveshaft angle. The way I have done it is somewhere between these two. Will be giving it a thrashing on Saturday. I haven't seen anyone achieve rear shocks with my method yet either. :blush: An unmodified car is still excellent. For example Grant Williams was in the A-final at Oswestry with his car unmodified. So its all down to personal taste. Don't just follow a trend like a mindless sheep thinking it is necessary, as it isn't always. ;) |
U3529 Cat SX Rear Shock Conversion
Schumacher will shortly be releasing a little conversion bag to move the shocks to the rear, the bag includes the hardware to do this as well as a new link mount to move the ball forwards to miss the shock.
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Where's the info on this boss
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Im intrigued
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Hay Chris, Jonesy was running the standard rear end too and he made top of the B at Ozfest....
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Yeh, Jonesy did well, I wanted him to make the A final.
I was just making the point that rear mounted shock mod may be more of a trend than a necessity. So dis-couraging everyone jumping on the band-wagon. Fair enough people trying it, I am, I intend to also try other mounting methods over time (possibly during Belgium). But im quite prepared to go back to front shocks. |
We made the change at Talywain like Chris said to try and allow the car to handle the smaller bumpy sections better. Shocks at the rear of the car have allowed me to run a stiffer back end with bigger hole pistons, allowing us to reduce some of the pak.
All i have done is drill a hole in the rear of the wishbones to allow me to just change the shocks rather than the wishbone direction aswell. With the wishbones flipped round i wanted to reduce the angle of the driveshafts to a more level angle, hence returning the wishbones to the original place. This is somethin we as a team are going to continue to develop, but the good thing is we have an extra option to try rather than just the standard shock layout. Si |
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Discostu ran his Cat last night at Faversham with the rear shock mod, he did by turning the arms and mounts round and cutting down the rear bumper.
The car looked good and drove well when I had a go with it. Stu get some pics up if you can! |
Yeh chris where's the pic's you promised :p:p
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LOL, in a minute or 5.... :lol:
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Those are the pictures. If anyone needs to see any other angles, just let me know and I'll do it.
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Think you've covered it fella :thumbsup::thumbsup:
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Chris you my hero :p
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:wub :lol:
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At Oswestry i mounted the shocks on the back of the wishbone, with wishbones in right place, to do this, dill a new hole on back of wishbone move shocktower to the rear of bulkhead, get a 30mm screw to attach shock so this clears the camber link, car felt alot better like this!
To run the wishbones around, dill a new hole for the roll bar, turn the wishbones around, leave shocktower on the back of bulkhead, job done, not sure why you need to play around with blocks or cut bumpers like Chris has done, mines fine, car was much better like this than with wishbones the same way, could throw it a lot harder into the corner and get on power much earlyer too! I am even running mine with the quick klips at the back of wishbone to make it even shorter! Pics below, i have made my own carbon bracket to straighten up the cambe links but thats it! http://photos-h.ak.fbcdn.net/hphotos..._8084987_n.jpg http://photos-a.ak.fbcdn.net/hphotos..._6807318_n.jpg http://photos-b.ak.fbcdn.net/hphotos..._2524334_n.jpg http://photos-c.ak.fbcdn.net/hphotos..._1480679_n.jpg |
The reason I have done it my way and not yours is - I don't need to make a new camber link mount, and I don't need to drill new holes on the wishbone (which im not confident I can do evenly - which would spoil the whole point in doing it)
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been thinking about the way you have done it chris, and it isnt going to shorten the wheelbase, which is what turning the wishbones around acheives and provides more traction!
not saying your way is wrong by any means Paul |
hey paul
i had a little play last night with the wishbone mod i turned the rear arms and hangers around when you do this the wheel base is about the same as standard position it seem to genarate good on power traction i think the only fair test can be done is to try all methods back to back i tried the same mod on the d4 and it seem to create the same effect it would be good if shumacher would bring a option to do this. stu |
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just re read your post its not just to shorten wheelbase it also to move the weight distribution of the rear of the car which would make a bigger diffrence in my opinion. i also tied the same mod on my corraly rdx phi the arms were kept the same just moved the shocks and on my tc it locked the back end of the car so much so i struggled to get it to rotate on tight high bite tracks. stu |
You say there the same lenghth but it should be shorter!
Mine is about 5-7mm shorter depending where spacers are than the standard cat, but we noticed at racing last night, 3 cats with the mod with wishbones around, all had different wheelbase, which is strange! Paul |
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yeah if you turn just thre arms around it is much shorter if you turn the hangers around and trim the bumper it moves the rear arms further rear ward i sat mine next to a standard cat last night it was pretty much the same certanly not 5-7mm diffrence i think it all depends on how the mod is done. stu |
I have to admit, I didn't catch on straight away that Chris was talking in his initial post about turning the blocks round as well - this will keep the wheelbase "similar".
Personally, I have tried is with just the shocks moved - and wishbone drilled, and this made maybe a tiny difference. I then tried it with the wisbhones flipped, and the wheelbase shortened by a chunk. This felt good, but maybe a touch too much. I have since modified some bits to take the wheelbase back 2mm, and this feels good. It is shorter than std, but not as short as it can be. Schumacher are indeed making a small kit of parts to reverse the shocks. I'm not 100% sure what parts are coming in that kit to be honest, but it should be available shortly. |
ive just measured the wheel base standard is about 278 depending on spacer location mounts and arms turned round measures about 277 again depending on spacer locations.
stu |
I don't want or need to shorten the wheelbase, I generate a bucket load of forward traction already. Doing the way I have done means the wheelbase is around 1-2mm shorter, no more, than a standard car. But aswell as not needing to drill and risk uneven distance holes, nothing except the bumper is modified and so I can easily put it back - and use parts when the Schumacher kit is ready.
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This thread reminds me of touring cars.
You should be ashamed of yourselves :lol: |
:blush: Now YOU say it, I am, I really am.
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Rear mod now available, info from Schumacher - :)
New CAT SX Rear Shock Conversion The new CAT SX optional shock layout modification has been developed by the Schumacher design engineers in conjunction with our Race Team. It has benefits for varying types of tracks, however is especially good on very bumpy ones and those with low traction. The tuning bag comes with all the parts required to reverse the shock position to mount on the rear of the wishbone and reduce the wheelbase by 6mm. This enables greater rear weight bias, a more angled rear driveshaft and a more rearward wing position. All these things give the car more rear traction, however at the expense of high speed steering on most surfaces. The new 4mm thick C/F camber link bracket included in the pack also allows for multiple link length’s due to its alternate hole positions. |
It's great to see the team and schumacher going forward with idea's like this and bringing them to the masses. :thumbsup::thumbsup:
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ive been reading this thread and scratching my head. personally i dont believe there is an issue with where the shocks are on the rear end. myself and matt both made the A final at the tally national to be fair i didnt drive that well in the finals but matt qualified and finished very respectable. and then with oz car was awesome from the word go another solid A final. dont think the car could of been better. within the finals i felt i could push alot harder than mossy and was a touch quicker when together in the finals.
this dosent mean to say the next look rear end is wrong as i havent had a chance to try it out. i personally think the issue with the rear end could be solved by increasing the volume of the shocks. i have metioned this the the big man :thumbsup: |
Just seen the pics on redrc, so does this mean you swap the blocks/arms round to mount the shocks on the rear?
I take it does as just drilling the arms will keep the same wheel base and it mentions short wheel base in the info |
well i have see the schumacher mail news to day...:thumbsup:
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