zetecspit Posted April 17, 2016 Share Posted April 17, 2016 Now I am brave enough to give the new diff some abuse, I have found the car suffers from tramping. If there a way to reduce this? Spec is Scooby 160 diff Std (ish) rear transverse spring CV jointed shafts on nicks Rotoflex uprights, std GT6 mk2 radius arms. Koni shocks I suspect without major re-work the answer is skinny slippy tyres or no hard starts....but you never know! Cheers Clive Link to comment Share on other sites More sharing options...
esxefi Posted April 17, 2016 Share Posted April 17, 2016 it can de designed out,but a bit harder if you retain the leafspring.ideally needs a top wishbone and careful positioning to provide antisquat. probably why you don't find many serious drag cars without a live axle as it's easier to dial out of the set up. there are some schematic diagrams on the web showing the theory of it,can't get one to paste though.punch in 'anti squat' under images. Link to comment Share on other sites More sharing options...
Nick Jones Posted April 17, 2016 Share Posted April 17, 2016 Hmm...... never got mine to tramp...... though I don't make a habit of high energy launches out of respect to my diff/wallet! My faather Mk4 Cortina was the king of axle tramp though even with a limp and asthmatic 1.6 pinto. I'm inclined to blame the diff mounting not the suspension though - and I say this because surely the torque reaction is passed back to the diff and not the vertical links. Is it your long pressed-metal front mounting plate flexing? Nick Link to comment Share on other sites More sharing options...
zetecspit Posted April 18, 2016 Author Share Posted April 18, 2016 I like your thinking on that front plate. It really seems to have little stiffness, and yes, it seemed to have flex even with me pushing it in situ. Maybe I will have to develop some bracing sections. My general opinion is that the spring "bracket" and that front plate are both under designed. Hence my spring bracket has fishtales, 6 in all though 4 may have been enough in just the corners (I have a pair central to the spring line too. Maybe the solution is a horizontal fillet or 2, at least as a starting point. But that will have to wait, the issue can be controlled by not launching the car. Maybe there is an advantage to having a fear of breaking the diff! Link to comment Share on other sites More sharing options...
Nick Jones Posted April 18, 2016 Share Posted April 18, 2016 You may also be taking the lead in the extreme durability testing of the Rover 100 shafts and CVs....... Nick Link to comment Share on other sites More sharing options...
zetecspit Posted April 18, 2016 Author Share Posted April 18, 2016 Those shafts were used on a lotus IIRC, and certainly the MGF 160's etc (ok, slightly different lengths) so should be more than adequate for what the zetec can produce. I hope! I was thinking of an ST170 on ITBs with the cam properly controlled That would put power a tad over 200bhp at the flywheel. But with a nice flat torque curve. Maybe I should stick with the easier/less complex standard 2 litre and be happy with that. The cars seem to struggle at this end of the scale. Besides, the limiting factor is that I am a numpty driver with less than honed skills! Link to comment Share on other sites More sharing options...
Bobbyspit1 Posted May 5, 2016 Share Posted May 5, 2016 Clive, sorry mate whats Tramping? Sorry found it on youtube https://www.youtube.com/watch?v=BVQ5iZQTQJI Now I am worried I have the option to add traction control to the MS? Rob​ Link to comment Share on other sites More sharing options...
zetecspit Posted May 6, 2016 Author Share Posted May 6, 2016 I have noticed the diff if banging on the tub when I try ie stabbing the accelerator or changing gear a little hard. So there is some movement happening. I plan to have a proper look soonish, but have the CT autosolo this weekend. That will give it a workout.... I am hoping a stiffener rib or two across the plate will solve the issue. An essentially flat 5mm steel plate that is 300mm (guess) between centres is probably asking too much. Link to comment Share on other sites More sharing options...
zetecspit Posted May 6, 2016 Author Share Posted May 6, 2016 As I am waiting for a call back from the council, I decided I had plenty of time to crawl under the car. And the cause of the banging is revealed. One of the 4 (offside front) 12mm boltheads bolting the diff to the front mounting plate is hitting a bracket which I think is the old handbrake quadrant mount. The gap at rest is approx 15mm, but if I push the nose of teh diff up with my hands I can see the plate flex a little, and get a few mm of lift. Looking at the plate reminds me that not only is the plate 300mm wide (ish) but also long http://www.triumphcars.com/images/fm70893u/124.jpg so needs extra strength/flex resistance side to side AND front to back. And not much space available. And not a job that can be done without getting the plate off.... Link to comment Share on other sites More sharing options...
zetecspit Posted May 6, 2016 Author Share Posted May 6, 2016 And still waiting for the phonecall............. Link to comment Share on other sites More sharing options...
Nick Jones Posted May 6, 2016 Share Posted May 6, 2016 15mm.......! How much would it move if that bracket wasn't getting in the way? They are a long and flexible shape and I've never liked the 2 dimensions only design. Slightly different take on it here http://sideways-technologies.co.uk/forums/index.php/topic/7092-steel-r160-diff-plate/ but I'd still like to see a 3rd dimension added longitudinally - the absence of that is what is causing your flexibility. Nick Link to comment Share on other sites More sharing options...
zetecspit Posted May 6, 2016 Author Share Posted May 6, 2016 I was going to make a plate out of 8mm steel, but the 5mm one ws offered all pre-cut etc so seemed a good idea. I may be able to drop teh plate off the diff in situ, and I have some bits of box section and other stuff kicking about. I was asked why I used fishtails on the spring bracket, I think this issue explains why! A few extra ounces of metal well spent. Link to comment Share on other sites More sharing options...
pomwah Posted May 6, 2016 Share Posted May 6, 2016 And still waiting for the phonecall............. "Ring, ring" Link to comment Share on other sites More sharing options...
zetecspit Posted May 6, 2016 Author Share Posted May 6, 2016 Ah, sorted. Nice council lady, met her, showed her some plans now and all smiles and agreement. I suspect it took a while for her to get the message from reception! Actually, she remembered me from 5 years ago when we last had dealings, and she has been my point of contact now for over 10 years. All good and dandy! Plus the weather is gorgeous, a fine day to live on the south coast of this normally damp island. Link to comment Share on other sites More sharing options...
zetecspit Posted May 7, 2016 Author Share Posted May 7, 2016 Slipped onder the car, and fitted a 12mm thick exhaust hanger strap as a bumpstop, using a bolt through the strap and onto the redundant handbrake quadrant bracket. I don't expect it to last forever, but I was thinking the 'solo tomorrow may get tiresome, plus restricting the movement will reduce fatigue on all the brackets. While under there I got thinking. I reckon moving the chassis diff mount brackets right forwards may be the solution......after all the sensible position is as far forward on the diff as possible. Link to comment Share on other sites More sharing options...
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