View Full Version : IRS versus standard beam on a fast road/track car
Hi i was wondering if there would be much advantages in getting rid of the standard solid rear beam and converting to IRS? i know the camber and toe would be made adjustable(but it carnt be that hard making it adjustabe with the standard rear beam?spacers and tubbed rear arches with slotted holes like a BMW front strut?)
Would you really feel the benefit or is it mainly for rally cars?
Discuss lol
craig green
04-10-10, 10:43 PM
Sounds like a lot of work. But IRS is clearly better.
can you justify the cost/time involved & definately shave x amount of seconds from your lap times?
the best way to do it imo would be to find a car that has irs on a rear subframe and graft it in.
But bear in mind that unsprung weight should be a high priority
SR-Rally
04-10-10, 11:03 PM
It would be better but alot of work. My friend was in the middle of converting a spare shell he had to IRS, extremely gifted driver and machanic. Unfortunatly it will never be finished. :(
craig green
04-10-10, 11:09 PM
Something from a Honda/Rover maybe.
Hmmm i have a CTR sat on the drive!lol i have seen the H.H kits but is there anymore?
Yeah i presume it would have to be made out of alloy or if feeling flush titanium to keep the unsprung weight down!
If there was 2 Novas with identical specs on the same track(say combe) apart from one had standard beam and one had IRS.Roughly how much would it be quicker by at a guess?1 second? 3 seconds?
to be honest i dont think that the beam is a weak a link as its portrayed, theyres a LOT of flex in it
the problem with retro fitting irs is that it would be guess work, car companys spend millions on suspension development.
Do you use said car for serious competitive motorsport?
I didnt think so either.
Do you use said car for serious competitive motorsport?
I didnt think so either.
No i dont,as a matter of fact i dont even own a nova at the minute(just own loads of random parts for onelol )BUT i will more than likely be building one in the none too distant future and was just asking for opinions and thought it would be a good subject non the less.
It is a good subject not denying it, BUT so much for next to no gain IMO espcially given a non competitive situation.
You'll gain a couple of mm of adjustment either way & spec sheet will impress the man. Other then that, alot of cost for virtually no daily "useful" gain.
If IRS was so good on a SWB hatchback, every man an his petrol head addicted car owners son would have it fitted to all manner of track car. Ala 205 GTi's, 106 GTi's, RS Turbo's, Saxo's etc etc theres a lot of gifted poeple out there on other car owners forums that could easily do it, obviously they chose not for a reason.
I thought about it for a while a few years back just as something to do to pass the time lol
My idea was to lop the middle of the beam out, change the beam mounts for rose joints, and then add two droplinks from each half to some central mounting points on the chassis via more rose joints.
I know its crude but it was only a daydream OK lol
Could the money/time spent on this be better spent on 4 pot Brakes and high end Coilovers and see better results?
Weight removal & distribution. Free of charge.
craig green
04-10-10, 11:56 PM
the problem with retro fitting irs is that it would be guess work, car companys spend millions on suspension development.
Yeah but we undo it all in our sheds & driveways. lol
Nova's handle better with uber stiff ass ends anyway. Fitting IRS would be pretty negligable in the results dept IMO. Thats why it only stayed as a daydream lol
What I love to lol at this the size/thickness/rigidity of a standard 205 GTi rear beam compared a Nova one.
No wonder Nova rear ends go all outta shape on standard unmodified ones :S
imo its surprisingly cheap and simple to do, just requires abit of thought, wish i had finished it on the saloon now
Steve0011
05-10-10, 09:41 AM
imo its surprisingly cheap and simple to do, just requires abit of thought, wish i had finished it on the saloon now
have you got pics/description of what you did? :thumb:
basically weld a bit of cds tube between the beam mounting points to make the inner mounting points for some very simple trailing arms which attach to the original beam mounts and these new inner mounts.
Colin Smiths old Nova had IRS :
http://i5.photobucket.com/albums/y191/mrmazz/png%20nat09/PICT0079_Small.jpg
http://i5.photobucket.com/albums/y191/mrmazz/png%20nat09/PICT0080_Small.jpg
http://i5.photobucket.com/albums/y191/mrmazz/png%20nat09/PICT0082_Small-1.jpg
davidfox280585
05-10-10, 11:08 AM
rs turbos come with irs mike, though my s2 handle awful compared to my combo, corsavan,cavalier and the nova they handle pretty well just slammed i dont think it would be worth the effort the solid beams aint too bad
Do they David? Didnt know lol was just using that kinda car as a "hot hatch" example like lol
the rear beam has been fine for a lot of years on the nova/corsa etc... when people try to engineer more comfort into cars because the marketing people demand huge wide low profile wheels tyres.... they need to come up with clever stuff for comfort... thus those stupid vertical bushes on the front lower arms that mike needs to swap on the breadvan, and all the clever stuff they used as an advertising thingy on the new astra.....
most of it is there to fix the fact that the tyres give too harsh a ride. and good old fashioned suspension like on a nova is actually very good. the beam is exactly the same as having simple trailing arm irs & an antiroll bar.
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