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Post by 00crewchief00 on May 4, 2016 20:36:22 GMT 12
Has this been done before?
Obviously it may be weaker and not stand up to heavy contact but would have handling advantages.
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Post by Deleted on May 4, 2016 20:51:43 GMT 12
been done a few times - has to be a super instead of a normal stocky though due to the open driveshafts.
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Post by 00crewchief00 on May 4, 2016 22:28:40 GMT 12
Well that sux! There goes that idea.
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Post by nrp165 on May 5, 2016 17:43:29 GMT 12
isn't the problem a lack of forward drive?
I can see the advantage in reduced unsprung weight......but you can't achieve high levels of anti-squat with an irs?
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Post by 00crewchief00 on May 5, 2016 23:09:27 GMT 12
V8 supercars are now IRS they seem to go alright lol as do drift cars.
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Post by nrp165 on May 7, 2016 15:36:20 GMT 12
go for it then...........I obviously don't know what I'm talking about
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Post by Roger Ex 35A on May 7, 2016 18:08:04 GMT 12
go for it then...........I obviously don't know what I'm talking about Not true Vic rather follow your advice any day. Any way different as chalk & cheese, Aussie V8's tarmac, Stockcars dirt  |
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Post by 00crewchief00 on May 7, 2016 18:25:07 GMT 12
The jap street stocks handle pretty good too. And that's dirt rite? Lol ;p
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Post by The Observer on May 7, 2016 19:45:53 GMT 12
Hi crew chief Here's a thread on the rockets that nrp165 has built over the years. macgor.proboards.com/thread/3998/nrp-racecarsAt one stage he had the fastest superstock in the country, and was unlucky to be leading in points going into heat 3 of NZ title in HB. Unlucky, as there were 10 Rotorua cars in that final, with only one of them up on points. |
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Post by Roger Ex 35A on May 7, 2016 21:06:46 GMT 12
Hi crew chief Here's a thread on the rockets that nrp165 has built over the years. macgor.proboards.com/thread/3998/nrp-racecarsAt one stage he had the fastest superstock in the country, and was unlucky to be leading in points going into heat 3 of NZ title in HB. Unlucky, as there were 10 Rotorua cars in that final, with only one of them up on points. Enough said "TheObserver" I rest my case  |
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Post by 00crewchief00 on May 8, 2016 7:50:21 GMT 12
I do know who Vic is and what he has done I've even been inside one of is sheds, when the clout car was being converted. So i realise how great he and is knowledge are.
As i said however it has no relevance as its not available to stockcars only super which have roughly double the power and torque thus they would squat alot more from the start if using IRS.
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Post by Deleted on May 8, 2016 14:03:50 GMT 12
Ive looked at irs a few times in the superstocks, was considering building one with it for myself. Now this is based on what I researched and what others have already tried....
The up side - DOES take the hits. And with the flexible nature it handles exceptionally well in the arse of a super. your forward traction is great especially on a rough track - soaks up the bumps and puts power down far better than a live axle can. also if one side gets damaged its not night over or replace the whole shebang - its swap out that side alone. If you get pu on the wall - you drive off far easier than a live axle equipped car does and with an lsd instead of a locked diff your car turns and changes direction quicker as well.
Down side - CANNOT take off as fast, the flexibility is its undoing here. with so many universals and moving parts the off the start line get up and go is pretty bad, too much power and you will break your universals just trying to start each race. also - no anti squat, the system is flexible and limited at the same time by design and by nature, you can get fantastic forward traction - but your car will never handle like a live axle one and comparing a car with irs to a car with live axle is about as useful as comparing apples with pumpmkins. theres a world of difference...
thats the brief overview of what Ive learned - each car is always different anyway but irs is a whole new ball game. any setup tips and tricks for a live axle car are at best taken with a pinch of salt because even being a different car can mean it wont work - and this is a totally different drive system setup as well.
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Post by chris13w on May 8, 2016 22:20:20 GMT 12
Ive looked at irs a few times in the superstocks, was considering building one with it for myself. Now this is based on what I researched and what others have already tried.... The up side - DOES take the hits. And with the flexible nature it handles exceptionally well in the arse of a super. your forward traction is great especially on a rough track - soaks up the bumps and puts power down far better than a live axle can. also if one side gets damaged its not night over or replace the whole shebang - its swap out that side alone. If you get pu on the wall - you drive off far easier than a live axle equipped car does and with an lsd instead of a locked diff your car turns and changes direction quicker as well. Down side - CANNOT take off as fast, the flexibility is its undoing here. with so many universals and moving parts the off the start line get up and go is pretty bad, too much power and you will break your universals just trying to start each race. also - no anti squat, the system is flexible and limited at the same time by design and by nature, you can get fantastic forward traction - but your car will never handle like a live axle one and comparing a car with irs to a car with live axle is about as useful as comparing apples with pumpmkins. theres a world of difference... thats the brief overview of what Ive learned - each car is always different anyway but irs is a whole new ball game. any setup tips and tricks for a live axle car are at best taken with a pinch of salt because even being a different car can mean it wont work - and this is a totally different drive system setup as well. Well, there are some correct bits and some not so correct bits in that description... Main advantage of IRS is unsprung weight, which does help handling, but probably not to the same degree on dirt as it does on a firm surface. You CAN get anti squat on an IRS, the Lotus 72 F1 car was famously designed with LOTS of it - they took it straight back out again though, as it was impossible to drive. (Chapman wanted to use anti dive and anti squat at each end to keep the car at the same ride height, probably for aerodynamic reasons, more than anything else). On an IRS its done by making the instant centre of the longitudinal links point uphill towards or above the centre of gravity - but what that means is the linkages bind up horribly under power, which is not a good thing. Anti squat on a dirt car is different to pretty much any other form of racing, as its done with lift arms - and preferably birdcages to take out any of the bind in the suspension linkages. So you can get big amounts of anti squat, without the bad side affects - so that plants the tyres off the turn - drag racing suspension is probably the only similar concept. Of course, lift bars are also banned on Stockcars aren't they, so its not really much of a factor anyway in the class? As to if its strong enough, guess that all comes down to how well its built. And just fixing one side when damaged, is probably no easier than just taking out a complete axle assembly is it? I guess its all academic if you aren't allowed them in the rules though. |
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Post by Deleted on May 9, 2016 13:59:02 GMT 12
Well I suppose I should have said anti-squat is difficult, instead of saying there is none... as for unsprung weight - yes, its a handling advantage - but I personally would say the important advantage for us is less possible damage to the more expensive suspension components of the system, purely a cost/saving thing....
Fixing one side of the irs on my b saloon does seem alot easier and quicker than fixing a winters diff with damage on one side - just like a normal closed tube diff, I can replace an axle in minutes while it can sometimes take that long just to get a quickchange out of the hole on other cars. its literally undo two bolts and I can slide the axle out on mine if I hold the hub etc out of the way....
Moving on though - lift bars are still legal for stock cars, but yeah the irs is still illegal due to open tube design so still an academic debate.
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Post by nrp165 on May 9, 2016 18:47:33 GMT 12
Hi Chris...........in the interest of always learning,I'll hijack this post.
I can understand the anti-squat effect of angling the rear radius rods upward.
But if the wheel's spinning-high horsepower on dirt,for example-surely this is negligible-whereas a torque arm/lift bar plants the wheels irrespective of traction-which then increases,and so-on
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Post by chris13w on May 9, 2016 20:27:12 GMT 12
Well I suppose I should have said anti-squat is difficult, instead of saying there is none... as for unsprung weight - yes, its a handling advantage - but I personally would say the important advantage for us is less possible damage to the more expensive suspension components of the system, purely a cost/saving thing.... Fixing one side of the irs on my b saloon does seem alot easier and quicker than fixing a winters diff with damage on one side - just like a normal closed tube diff, I can replace an axle in minutes while it can sometimes take that long just to get a quickchange out of the hole on other cars. its literally undo two bolts and I can slide the axle out on mine if I hold the hub etc out of the way.... Moving on though - lift bars are still legal for stock cars, but yeah the irs is still illegal due to open tube design so still an academic debate. I'm not a Stockcar person - its 5th coils on the end of a lift bar that are banned then isn't it? |
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Post by chris13w on May 9, 2016 20:51:01 GMT 12
Hi Chris...........in the interest of always learning,I'll hijack this post. I can understand the anti-squat effect of angling the rear radius rods upward. But if the wheel's spinning-high horsepower on dirt,for example-surely this is negligible-whereas a torque arm/lift bar plants the wheels irrespective of traction-which then increases,and so-on Anti squat is the amount of force resisting the "sinking" affect on the rear end. With a mechanical linkage like a 3 or 4 bar, its a function of where the instant centre intercepts the CG - so level bars are going to be about 0%, where as something above the CG will be 100+% (But extreme angles cause binding). So if its got more than 100%, the back end will lift - and that means there is downforce on the rear tyres, just with extreme binding and lots of other negatives. (Presumably the tyres are spinning less when they have force pushing them into contact though). With a lift bar, its a function of the engine torque, diff ratio and the length of the lift bar as to how much force there is downwards on the rear tyres, and if the axle is rotating in bearings, then the linkage can be free of binding at the same time. So they are different types of leverage causing the downforce, and yes, I agree with you - its why a lift arm is better than an IRS on dirt, from the point of view of traction. Where as on most other surfaces, an IRS will be better for overall handling. (Except drag racing, because a dirt track is just two drag strips connected with corners).  |
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Post by Deleted on May 9, 2016 22:25:23 GMT 12
Well I suppose I should have said anti-squat is difficult, instead of saying there is none... as for unsprung weight - yes, its a handling advantage - but I personally would say the important advantage for us is less possible damage to the more expensive suspension components of the system, purely a cost/saving thing.... Fixing one side of the irs on my b saloon does seem alot easier and quicker than fixing a winters diff with damage on one side - just like a normal closed tube diff, I can replace an axle in minutes while it can sometimes take that long just to get a quickchange out of the hole on other cars. its literally undo two bolts and I can slide the axle out on mine if I hold the hub etc out of the way.... Moving on though - lift bars are still legal for stock cars, but yeah the irs is still illegal due to open tube design so still an academic debate. I'm not a Stockcar person - its 5th coils on the end of a lift bar that are banned then isn't it? Yup. just a question - youve wrapped your head around this better than i have after all - I have forward facing traction links on my irs and they mount to the bottom of the hub carries, If I was to lift the forward end of those links would that give a sort of antisquat effect to any degree? or just make it even more likely to step out on a slicker track? |
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Post by chris13w on May 10, 2016 19:17:42 GMT 12
I'm not a Stockcar person - its 5th coils on the end of a lift bar that are banned then isn't it? Yup. just a question - youve wrapped your head around this better than i have after all - I have forward facing traction links on my irs and they mount to the bottom of the hub carries, If I was to lift the forward end of those links would that give a sort of antisquat effect to any degree? or just make it even more likely to step out on a slicker track? Yes, if you raise the front mount of a forward facing link it will increase the anti-squat. Build it with some alternative mounting points (like a 4 link would have) and just experiment with it. |
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Post by Deleted on May 10, 2016 21:10:46 GMT 12
Yup. just a question - youve wrapped your head around this better than i have after all - I have forward facing traction links on my irs and they mount to the bottom of the hub carries, If I was to lift the forward end of those links would that give a sort of antisquat effect to any degree? or just make it even more likely to step out on a slicker track? Yes, if you raise the front mount of a forward facing link it will increase the anti-squat. Build it with some alternative mounting points (like a 4 link would have) and just experiment with it. awesome - last thing I needed to sort after anzac weekend {apart from the throttle getting stuck wide open!!!  } |
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