Hi,
Firstly an apology for the length of time it’s taken to get to the point of reviewing this ABR, you make plans and then life gets in the way, anyway it’s on the car and I’ve driven it!!! :shock:
The bar is very well made, radius’s are as large as are practical (good for fatigue resistance) and the fit is excellent. Please note the area of the inner wings of our car have already been opened up slightly to provide clearance around our previous ABR, it appears some cars need this and some don’t, each car is different, in fact each side of each car is different. Bare this in mind if you order one, any extra clearance needed will be small and easily achieve with a little gentle tin bashing/jacking.
On the road the transformation is remarkable; please understand that our car is quite modified now so it is difficult (impossible) to assess this modification in isolation but even compared to our previous 24mm bar this 25.4mm the feel is different, even less roll in the corners. Considering “normal” driving, the bar modernises the feel of the car, you’ll have to decide yourself if that’s a good thing or not? Gone is the rolling nature of the drive, replaced by a much flatter attitude, as I say much more like a modern car would be.
OK so with all of the above said should we all rush out now and order one? Unfortunately a question that sounds as simple as this is surprisingly hard to actually answer. To make an attempt to answer it we need to go through a few things regarding P6 handling and more specifically what the front end is doing. Gavin is way more up on all this stuff than me but this is the just of things, he may come along and elaborate or correct me
Lack of front camber recovery in roll is a big issue with the front suspension geometry, ie when the car rolls the geometry of the front suspension fails to correct for this and the front wheel tucks in under the car and it understeers. This can be seen in the picture below (24mm bar fitted), this eats tires as well as losing loads of time, and it also feels very disconcerting as the bloody thing just won’t turn!!! Increasing the roll stiffness at the front has an obvious effect on this, more stiffness = less roll = less wheel tucking in = better turning = improved times, which is all good
but unfortunately the front suspension is not working in isolation. A much stiffer front end, and this 25.4mm bar increases it by some 220% over standard, will increase weight transfer at the front which in turn reduces grip and will result in increased understeer. So we have two opposing effects contributing to our original goal of improved handling :evil: With our car we have increase rear spring rates so we have stiffened the rear as well so this lessens the weight transfer effect so we can take full benefit of the improved camber control without so much of the negative issues.
It is extremely hard to know how an otherwise standard car would handle with just this ABR fitted, my gut feel is that it may well be too stiff and all though the car would indeed roll less in the corners overall front end grip might actually be worse.
To most on here all of this is of little consequence as we are talking at the limit handling here, if you fit this bar and drive the car well within its limit all you will notice is the much reduced body roll, which will make it feel more modern. If you want to get the best out of it then fit in along with stronger rear springs, for an otherwise standard car it might be worth considering a mid-stiffness bar. A 22mm bar has been talked about, this might be more appropriate for an otherwise standard car, for reference torsional stiffness percentages over “standard” are listed below (Gav. feel free to check my math :?: ):
22mm bar 145%
24mm bar 188%
25.4mm bar 223%
If you go with stronger rear springs then obviously you can move towards the stiffer bars.
Please understand this is not an exhaustive scientific test, just the best we can do with short run time and limited resources, it would be nice to do back to back trials with various diameter options. The event on the 11th was in fact cancelled due to lack of entries so we are still seeking a full anger event to run on. The above is a review of our observations so far.
On a side note our car went through the MOT this morning without issue, MOT’s here are all state run, no garages, there is no “advisory” process it’s either right and passes or it fails. As most will know our car is no oil painting but it’s right in all the right places :wink: it’s nice to see that the look didn't prejudice the test
All for now, Tim
