Independent Rear

[Shortshift]

"I suspect that will be the prime differentiator..."

Thanks Sam - very helpful, but I'm not sure what 'that' is referring to in your reply above.  Are you talking about track surface quality being key to whether a DD or IRS would give best on-track performance in a Seven?  If so, I can follow that.

And hopefully Simon can add when he gets the chance.  I suppose that, really, I'm asking "why buy?".  Is it to make the car more comfortable when being driven on-road, or is it to extract improved performance when in track mode?

James

[aerobod - near CYYC]

It will be interesting to get the feedback on the on-limit behaviour compared with the deDion, along with comparable lap times for a given car for those who do the conversion. Hopefully a few people can do a benchmark of their cars on a track they are familiar with and as close as possible after conversion another set of laps with as many parameters the same as before conversion.

[BenF]

Hi James, I think Sam is saying that how well a car has been generally set up will outweigh (or cloud) the comparison of De Dion vs IRS.

I also agree that the effect of damping on car handling on the limit is very difficult to define and I cannot remember ever seeing it being the dominating factor, even in a couple of cases where I had a car break a rear damper during a race.  I would still argue global car balance is the main effect on limit handling.

Considering that most race tracks are smoother than public roads, I would imagine the main benefit is on public roads.

In terms of lap time, it is very rare to see a large lap time difference between different suspension concepts, unless one is very wrong in the first place.  This mod should be more about driving pleasure.

Oh yes and I also read LF, looks great, very nice job.  Looking forward to seeing this conversion on some 7s soon.

[Shortshift]

"I would imagine the main benefit is on public roads."

Great, I follow that too.  But is this public road 'benefit' primarily in terms of ride comfort, or outright performance, or just handling/driving pleasure now that you've added that dimension in to the mix?

Sorry to be stubborn about this line of thinking but I just want to know how I would enjoy the benefits.  As I said above, "why should I buy" (apart from bragging rights down the pub)?

James

[BenF]

I can't speak for others, but I always found that an S3 chassis tends to bounce around a bit too much on bumpy UK B-roads.  Not so much to affect performance, but more general driving enjoyment (my old S3 was very well sorted and was very quick through the corners).

I decided then to go for a CSR rather than an SV because I felt this bouncing was a limitation to enjoyment and I have not been disappointed.  It just is more comfortable on bumpier roads, you have to worry less about making corrections and reacting to the car moving around.  So I would hope to have a similar feeling with the IRS conversion.

[Simon.Rogers]

Ultimaetly I think road users will see most benefit.

We currently are not able to run it on the hillclimb cars due to MSUK rules but racing is OK 

Until I can drive it back to back its always going to be subjective but the increased traction should benefit any competition car.

[Shortshift]

"Ultimaetly I think road users will see most benefit."

Thanks Simon - good to have your confirmation of the view expressed by others - but at risk of sounding like a cracked record, how will this on-road benefit be recognised by the driver and, possibly, the passenger?  Is it improved performance (grip, traction, etc), or ride comfort (whether primary or secondary) or just control and overall handling - the driving pleasure element identified by BenF above.

As a potential purchaser (I'm guessing I could be within the target customer profile) I didn't think it would be this difficult to get to the crux of the "why buy?" argument!

Or is it just "bragging rights" after all?

James

[Simon.Rogers]

James

The gains are in all of the above things you have listed.

The first thing you notice is as others who have driven it and I myself described the lack of impacts "spreading" across the chassis.

You know the feeling, you see/feel the front wheel hit a service repair to the road surface and in that split second you brace for the impact at the rear.  Then it travels behind your backside across to the other wheel.  This feeling is removed.  Yes there is an impact but it seems to be isolated to the individual wheel and the damper/spring take care of everything.

As you will have read the car rolls significantly less and yet is not fitted with a rear ARB.

The way the car drives has not changed from your typical S3.  It's still perfectly balanced and nimble.

In my opinion you can not measure performance on the road.  That needs a stopwatch and as I said without identical cars that is going to be very very difficult to measure.

I would have done this to my hillclimb cars but rules currently prevent this being done.

 

Why Buy - signifficant improvement to ride comfort and i strongly suspect that this in turn will improve performance.

[Shortshift]

"Why Buy - significant improvement to ride comfort and I strongly suspect that this in turn will improve performance"

Many thanks Simon - I get it!

James