VHS Bilstein+ARBs kit review
I know it has been posted several times, but I thought I might share my recent experience with VHSs latest Bilstein + ARB kit.
For those not interested, simply skip this post :) . For those not bothering reading it all : it works great both on the road and on track (with sport tyres) but be potentially patient to find the right ride height. For those who care about the details
Thanks to this forum I exchanged with a lot of people here to enhance my wifes MG TF in order to obtain a reasonable daily car that could still be very enjoyable and quite efficient for track days. The initial suspension was the SP1 pack with its dampers amazingly still OK in terms of pressure and balance (less than 5% discrepancy when measuring them, no leak). So why changing? Well, as a daily driver the MG was way too harsh and felt like falling apart. On a smooth track it was OK though, but lacked a bit ultimate grip and didnt like curbs. For the ones who like technical details, the dampers were not correctly matched to the springs and in particular must have had a very bad rebound characteristic, bump being probably OKish. So time to change.
I was lucky to be involved with active chassis « a decade ago », in particular with active damping and semi-passive (LOL at that name today) and active ARBs so could, although everything is linked, assess spring, dampers and ARB independently.
Final body movements (not transients) having been OK in all directions with sport tyres (not semi slicks), and knowing how much comfort could go with grip and be addressed with dampers, we thought lets stick with the existing springs and look for top dampers. I know there are some adjustable ones on the market, I play with 4 ways on other cars, but I knew that fine developed 1-way or excellent wide range std dampers could do the trick and are fine for our use.. and pocket. Hence the Bilstein from VHS that have been widely described here. Once some adjustments done I used to like the balance of the original car and didnt want to ruin that, but talking to VHS around some technical terms convinced me they knew what they were doing and I went for there uprated ARBs as well. I was though afraid balance and comfort could be a problem as there ARBs are non adjustable sadly, a bit odd but well. Some members said ARBs were an interesting option regardless, so...
Now to the only little drawback. Fitting the kit was OK provided you have some time to do it but despite some care I initially had a shock: I wanted to maintain the original ride height, that is 10mm lower than std and went for the expected middle groove. All Ok at the rear, but the front looked more like a speed boat. I had 363mm instead of the anticipated 347mm. We tried all we could and exchanged in depth with VHS who proved to be very reactive. At the end I got my 347mm front, but that is on the lowest groove. It is not a problem though as it sits that way as it should on the middle groove. Explanations are various, tolerances playing together and 2 weeks driving the car on bumps to get the suspension settled. Due to the gas and also the damper mounting, each time you lift the car and go back the front seats amazingly high for a certain time, but it settles at the end.
My advice : fit the dampers and drive the car hard over bumps before doing a proper geo or thinking something is wrong. A week or so! To the ride height at the front: As we retain the std springs, I measured the spring stops distance and found that only the lowest grove gave me the same 29,5cm I had with the SP1 stops, so no way the middle groove could have worked in my case (the car sits on springs once some pressure is stabilised in the dampers). That was the only negative, was very confusing, but all well at the end.
To the test. On the road you can clearly feel the dampers are more sophisticated. Yes, they are generally softer. But they react sooner and are finer over small asperities, more progressive also. The biggest improvement is the rebound is now fine and the car is more like todays standards: a tad firm as as sport car should but ways highways more comfortable than and no more crashes. This has been reported before. The spring do still hold the car well and seem to go with the dampers. Someone looking for comfort only could just stop there, but then the car might be a tad on the soft side re roll and quick reaction on steering inputs, a bit lazy or easy going. Thats where the ARBs step in. On the road, the car doesnt suffer from right/left copying effects that could go with stiffer ARBs. In fact the car doesnt seem to feel stiffer over one side bumps, although not easy to assess apart from dampers (but some tests allow that). So no real negative in terms of comfort due to the ARBs. But some positive: the car feels like on rails at higher speed or when changing quickly directions. Steering feels better to that way, inputs being immediate. It is odd as you gain both stability and reactivity, which means the basic ARBs were far from optimal. The car is much more confidence inspiring.
On track, it is quite amazing. Grip is greatly enhanced by the suspension and sadly I didnt have my equipment to measure it precisely but I would say a tad over 1.1G lateral on Toyos is pretty amazing for such a car. It feels like on rail, is very reactive to steering inputs so less lazy and enjoyable while the controlled body roll, less than before, allows the suspension angles to work better (especially as camber cant be adjusted easily) hence a quite astonishing grip at the end.
My fears regarding the front/rear balance proved non founded : balance is pretty neutral, very safe and can be adjusted with front tyre pressure, I didnt feel the need to play with ARBs. Now given the car achieves greater speeds in no effort, doesnt roll and is like on rails while having great grip even over curbs, I thought perhaps when being over the limit the car would start to bite. Not so. The car remains as forgiving as ever, extremely high time constant for a small mid-engined car, no sudden brake away or behavioural characteristics change. Very easy to push it. It is probably best that way given the type of car it is. On a dry track only, to remain in line with the quick input reactions experienced over the range, and at the grip limit I personally would have wished a car that is still sharper and more reactive to lift off or throttle inputs in terms of front/rear balance. But hey ho! This is on track at the limit, it is not my race car (nor a race car at all!) and it is also to be used on the wet and on the road every day so it is for sure better this way. And still as sharp as some German sport cars and most important: it is really fun and very safe with this suspension, put a real grin on my face.
At the end the full VHS kit works great as a package on the road, giving the MG a comfortable modern ride, while thanks to competent development these simple components work great in terms of overall grip on track without affecting the car negatively or pushing it over the original concept. It simply enhanced the car over the entire user ranges and extended it (easier to live with while amazing on track).
I know one could still fit stiffer springs, but from experience that would be a bit too much IMHO on the road unless you have soft wall tyres or run only high speed Autobahnen or smooth roads or like it a bit harsh. I know there are adjustable dampers around, and that can be an improvement as if I would race only, which is not the purpose, I would have adjusted the damping a tad harder, but just a tad to retain the grip. But then the current compromise is just great, and no need to adjust anything and I am not sure affordable adjustable damper scan match that quality and most important development when it comes to defining the bump and rebound curves (usually they are standard and adjustability over the fixed range means second best compromise). The ARBs are fine as they are, as are the springs, both adequate on road and on track if running sport tyres. The car is IMHO anyway not really suited to high grip tyres (semi slicks or slicks) unless rebuilding it for it.
All just IMHO
I hope this helps
Claude
PS : not advertising, just happy as is my wife with this transformed MG despite the initial hassle with the ride height.
For those not interested, simply skip this post :) . For those not bothering reading it all : it works great both on the road and on track (with sport tyres) but be potentially patient to find the right ride height. For those who care about the details
Thanks to this forum I exchanged with a lot of people here to enhance my wifes MG TF in order to obtain a reasonable daily car that could still be very enjoyable and quite efficient for track days. The initial suspension was the SP1 pack with its dampers amazingly still OK in terms of pressure and balance (less than 5% discrepancy when measuring them, no leak). So why changing? Well, as a daily driver the MG was way too harsh and felt like falling apart. On a smooth track it was OK though, but lacked a bit ultimate grip and didnt like curbs. For the ones who like technical details, the dampers were not correctly matched to the springs and in particular must have had a very bad rebound characteristic, bump being probably OKish. So time to change.
I was lucky to be involved with active chassis « a decade ago », in particular with active damping and semi-passive (LOL at that name today) and active ARBs so could, although everything is linked, assess spring, dampers and ARB independently.
Final body movements (not transients) having been OK in all directions with sport tyres (not semi slicks), and knowing how much comfort could go with grip and be addressed with dampers, we thought lets stick with the existing springs and look for top dampers. I know there are some adjustable ones on the market, I play with 4 ways on other cars, but I knew that fine developed 1-way or excellent wide range std dampers could do the trick and are fine for our use.. and pocket. Hence the Bilstein from VHS that have been widely described here. Once some adjustments done I used to like the balance of the original car and didnt want to ruin that, but talking to VHS around some technical terms convinced me they knew what they were doing and I went for there uprated ARBs as well. I was though afraid balance and comfort could be a problem as there ARBs are non adjustable sadly, a bit odd but well. Some members said ARBs were an interesting option regardless, so...
Now to the only little drawback. Fitting the kit was OK provided you have some time to do it but despite some care I initially had a shock: I wanted to maintain the original ride height, that is 10mm lower than std and went for the expected middle groove. All Ok at the rear, but the front looked more like a speed boat. I had 363mm instead of the anticipated 347mm. We tried all we could and exchanged in depth with VHS who proved to be very reactive. At the end I got my 347mm front, but that is on the lowest groove. It is not a problem though as it sits that way as it should on the middle groove. Explanations are various, tolerances playing together and 2 weeks driving the car on bumps to get the suspension settled. Due to the gas and also the damper mounting, each time you lift the car and go back the front seats amazingly high for a certain time, but it settles at the end.
My advice : fit the dampers and drive the car hard over bumps before doing a proper geo or thinking something is wrong. A week or so! To the ride height at the front: As we retain the std springs, I measured the spring stops distance and found that only the lowest grove gave me the same 29,5cm I had with the SP1 stops, so no way the middle groove could have worked in my case (the car sits on springs once some pressure is stabilised in the dampers). That was the only negative, was very confusing, but all well at the end.
To the test. On the road you can clearly feel the dampers are more sophisticated. Yes, they are generally softer. But they react sooner and are finer over small asperities, more progressive also. The biggest improvement is the rebound is now fine and the car is more like todays standards: a tad firm as as sport car should but ways highways more comfortable than and no more crashes. This has been reported before. The spring do still hold the car well and seem to go with the dampers. Someone looking for comfort only could just stop there, but then the car might be a tad on the soft side re roll and quick reaction on steering inputs, a bit lazy or easy going. Thats where the ARBs step in. On the road, the car doesnt suffer from right/left copying effects that could go with stiffer ARBs. In fact the car doesnt seem to feel stiffer over one side bumps, although not easy to assess apart from dampers (but some tests allow that). So no real negative in terms of comfort due to the ARBs. But some positive: the car feels like on rails at higher speed or when changing quickly directions. Steering feels better to that way, inputs being immediate. It is odd as you gain both stability and reactivity, which means the basic ARBs were far from optimal. The car is much more confidence inspiring.
On track, it is quite amazing. Grip is greatly enhanced by the suspension and sadly I didnt have my equipment to measure it precisely but I would say a tad over 1.1G lateral on Toyos is pretty amazing for such a car. It feels like on rail, is very reactive to steering inputs so less lazy and enjoyable while the controlled body roll, less than before, allows the suspension angles to work better (especially as camber cant be adjusted easily) hence a quite astonishing grip at the end.
My fears regarding the front/rear balance proved non founded : balance is pretty neutral, very safe and can be adjusted with front tyre pressure, I didnt feel the need to play with ARBs. Now given the car achieves greater speeds in no effort, doesnt roll and is like on rails while having great grip even over curbs, I thought perhaps when being over the limit the car would start to bite. Not so. The car remains as forgiving as ever, extremely high time constant for a small mid-engined car, no sudden brake away or behavioural characteristics change. Very easy to push it. It is probably best that way given the type of car it is. On a dry track only, to remain in line with the quick input reactions experienced over the range, and at the grip limit I personally would have wished a car that is still sharper and more reactive to lift off or throttle inputs in terms of front/rear balance. But hey ho! This is on track at the limit, it is not my race car (nor a race car at all!) and it is also to be used on the wet and on the road every day so it is for sure better this way. And still as sharp as some German sport cars and most important: it is really fun and very safe with this suspension, put a real grin on my face.
At the end the full VHS kit works great as a package on the road, giving the MG a comfortable modern ride, while thanks to competent development these simple components work great in terms of overall grip on track without affecting the car negatively or pushing it over the original concept. It simply enhanced the car over the entire user ranges and extended it (easier to live with while amazing on track).
I know one could still fit stiffer springs, but from experience that would be a bit too much IMHO on the road unless you have soft wall tyres or run only high speed Autobahnen or smooth roads or like it a bit harsh. I know there are adjustable dampers around, and that can be an improvement as if I would race only, which is not the purpose, I would have adjusted the damping a tad harder, but just a tad to retain the grip. But then the current compromise is just great, and no need to adjust anything and I am not sure affordable adjustable damper scan match that quality and most important development when it comes to defining the bump and rebound curves (usually they are standard and adjustability over the fixed range means second best compromise). The ARBs are fine as they are, as are the springs, both adequate on road and on track if running sport tyres. The car is IMHO anyway not really suited to high grip tyres (semi slicks or slicks) unless rebuilding it for it.
All just IMHO
I hope this helps
Claude
PS : not advertising, just happy as is my wife with this transformed MG despite the initial hassle with the ride height.
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publié par vb @ 07:40
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