Just for a bit of fun I cut together sections of different laps to try and look at how differently the car behaves with the 2 different suspension set ups... [video=youtube;h3zBb5ZeKKw]https://www.youtube.com/watch?v=h3zBb5ZeKKw[/video] From the Feb and April 2016 trackdays at Knockhill Racing Curcuit. Worth noting that the ASTs were only tested on 2 hours of very busy track time, so the laps were a lot slower than the BCs - this is just an initial comparison to see how the car behaves with the 2 different set ups - I have no doubt the ASTs will be faster once I have more seat time. Note that all else is equal bar minor geometry changes (-5 minutes toe each side and -2 camber with the BCs vs -4minutes toe each side and -2.5 camber with ASTs) BC's have 70N/40N Springs; ASTs have 80N/80N (should be 100N rear awaiting AST to deliver) For reference BC Racing Best Lap: 1.02.52 (1.02.63 also) Best lap on the ASTs I could manage that night was a 1.03.6
It definitely looks like you're more comfortable/tuned-into the old set-up to me. Also seems like your at the point where the car won't give you much more on the old set-up and the bouncing about you're getting on the back straight (reminds me of me at Hampden on Sunday ) is pretty comical in the comparison. Also the AST's look like they've so much more to give at the Chicane and Clarks Decent times on road tyres too !!!
100% mate - by that point, I had a lot of confidence in the BC set up - especially after using your advice on the damper settings (front much softer than the rear). Was just getting used to the ASTs, and with all the red flag stoppages and questionable standards I only managed 35 or so laps on them. Will be really good with the firmer rear springs hopefully - really need to work on a more aggressive turn in at the hairpin with them also
@papps do you have any advice for Spring rates on bc's for a mainly road going r26 and a setup? Regards KT
Absolutely steve - a lot more compliant on the bumps - I hadn't noticed the difference, especially on the approach to the hairpin, until Mark. had pointed it out to me. I'm still firmly of the belief that the BC's are a fantastic package for the value they offer, but the ASTs are a weapons grade suspension set up, and the price reflects that.
Nice comparison there Papps, I've recently upper the rear Spring rate and dampers to match on my BC's which seems to have helped loads at Snetterton. I'm really tempted with some AST's now as the car is no longer in daily use, only downfall is having to deal with that useless prick Kurtis lol Sent from my iPhone using Tapatalk
Coming here from my other thread about suspension. I think would be of great value for people who really do racing to see how each shock performs and understand where the differences come. I've made a lot of research about the BC and i'm sure they are very linear which is not what we would love. So my plan is to really dyno them once I put my hand on a set. But the nice comparison would the KW against the AST. People are asking 20£ to test a shock, so the price is not big by any mean as long as we have the shocks. My plan is to transform the BC's in something as good as the AST if not better and I think I have a plan already. Just need to see how good is the base shock. S.
Why bother. If you move to an adjustable damper you have a range to play tunes with to hit a sweet spot with a variable set of requirements, conditions and set-ups. A base set of damper performance values is fairly meaningless in isolation.
This is where people are assuming wrong things. Having an adjustable coilover doesn't mean you can set whatever you want. Understanding how a shock absorber works helps a lot. Just some food for thoughts: - an shock has 4 main areas of interest: low speed compression, low speed rebound, high speed compression, high speed rebound. Imagine you have only 1 clicker - look for linear, progressive and disgressive valving. See how different they can be - how the clicker works: comp - rebound cross-over; how controlable is through the whole adjustment range - hysteresis If anyone is interested, I can talk in much higher detail about this with pictures and knowledge. S.
Sure, but a damper and the detailed analysis of its performance, whilst interesting, is only part of a larger suspension solution for the general level of requirements on this forum. Most work to a budget and overall handling requirement. They buy what they can afford and to be blunt, don't even get the best out of small damper variations when viewed as an integrated part of an overall performance/suspension set up. For example, papps on here wasn't on a great lap time on AST's because of his driving ref track traffic, nothing to do with damper performance. I'm sure we would be interested if there are any damper differences between a R26 and R26R, but when they are bolted to different Spring Rates, running on different mass vehicles, what's the relevance of the data?
So the whole suspension is divided in 4 diferent items: - shock absorber and the way it behaves in isolation - springs rate and force profile (linear, progressive, dual-rate) - most of the coil-over springs are linear and they exhibit the same force through compression, so saying 7kg/mm should be the same unrelated with the brand - weight of the car, weight of each corner - being the same car, the weight should be very simillar. We are not running F1 cars and 20kg +/- will not make us change the shocks - suspension layout (arm position, point where it connects to the chassis) - because we talk about the same car (and M3RS has the same base layout of the front suspension), we can consider last point as not part of the discussion - suspension set-up (camber, caster, toe in/out) - this is something we are already discussing in here. If we want to become better (personally and as an community) we have to start from somewhere. Dyno-ing a shock is 20-30£, so nothing we can't deal with. Also, the shock has a great impact on how car is cornering, how we feel the car, how it behaves on the streets. Understanding this kind of things will make people choose the products they buy not by the colour or opinions on the forum, rather some more documented opinions. I'm not saying anyone should do it. Everybody is free to do whatever it wants. But I'm going to follow this path for my car and I'm just looking to see if there is anyone interested in this or not. Coming back to the R26 vs R26.R discussion, there are a lot of people on the forum who installed R26.R shocks on they're R26 and they rate them highly, even with the increased weight of the R26. But the price is so high. So having the data, what if we discover there is a much cheaper shock that can perform the same as the R26.R? What is we modify a shock to behave like one? What is we improve out own coilovers (BC, AST, KW...) to be much better suited to our needs? S.
Forum didn't care about my formatting. So the whole suspension is divided in 4 diferent items: Shock absorber and the way it behaves in isolation Springs rate and force profile (linear, progressive, dual-rate) ' - most of the coil-over springs are linear and they exhibit the same force through compression, so saying 7kg/mm should be the same unrelated with the brand Weight of the car, weight of each corner ' - being the same car, the weight should be very simillar. We are not running F1 cars and 20kg +/- will not make us change the shocks Suspension layout (arm position, point where it connects to the chassis) ' - because we talk about the same car (and M3RS has the same base layout of the front suspension), we can consider last point as not part of the discussion Suspension set-up (camber, caster, toe in/out) ' - this is something we are already discussing in here. S.
If your trying to do the job properly and understand the basic calculations its very important to know. I have bad personal experience of this. I calculated what I thought were correct front and rear spring rates for my 944 race car based on a mixture of known spring values from several different race car setups and some basic theory. I then bought a race damper set from GAZ that was supposed to be bob on for the car and those sort of rates. Wasted my first season racing as the car suffered from comical roll oversteer into corners that couldn't be corrected with damper adjustment. Later when I had them dyno'ed it was plain to see, the rears had loads of low speed damping, the fronts practically none. Twiddling the adjusters didn't alter that fact just made em stiffer or softer overall i.e. it did very little to change the fact that the rears had loads of low speed damping and the fronts none. The outfit that I knew who loved the GAZ dampers were running front springs 150 lb/inch stiffer than mine but they only got there by trial and error over several years (they had no logical reason why their spring set was the business other than that they had spent several seasons tweeking their way to it). This is what it comes down to really, you can get really close to optimum straight off the bat or one can burn the cost again mucking about with multiple spring sets and endless testing.
That's a confusing post. You went for a front spring rate that was 150 lb/inch softer than a well proven Gaz set up and then had issues.
What I think NJH is trying to say is very similar with what I was saying a couple of posts above: this forum only compared shocks based on they're label and spring on rate. We should go deeper into shock dyno-ing if we really want to understand something or improve our cars. Until then, is just bragging of who got the most expensive shocks or the stiffest springs. S.
NJH was talking about a suspension set up for racing, so depending on the series Tech Regs you are either constraining to fixed spring and damping with no choice or you could be free on either or both. In any case, if you had free choice, then you do the research and find out what suspension the front runners and teams are using and have honed with experience. That is more important than a bit of random damper technical data. In any case, if you had free choice on springs and dampers and you were really concerned about being competitive, there would be better choices than Gaz.
I did and I bought spring rates based on that data. I didn't know at that time what one particular outfit who developed the GAZ system was running as they are very secretive about it, GAZ themselves also a bit useless as they had their own spring setup which was really just a fast road setup similar to that they bung on every car (completely different spring rates to the successful race setup). If one looks carefully at a lot of aftermarket systems they often show the signs of setups that really haven't been developed at all, look for example at the number of systems using 450 lb/inch or so springs. Front running teams closely guard their suspension setup data, I don't know of a single example of any suspension manufacturer which supplies exactly what the front running teams run as for front running race teams this stuff is well within the realms of what they consider to be their IPR. I know a guy whom for example has run cars for years in the very tight MX-5 championship (used to be MA5DA), every damper set they got went straight off for testing and perhaps rebuild, they also had their own secret springs and setup data. If one looks at the regs they pretty much always say springs are free even if they specify a particular damper make and model. Did you know for example that there is sometimes poor correlation between what the damper clicks give in terms of damping on one set of dampers to another, or worse the left and right can give different results for the same number of clicks. You only find this stuff from dyno testing. Ultimately this is the difference between real experience from racing and ill informed assumptions.
I do sense from your posts NJH that your delve into racing was not a particularly enjoyable process. Anyway, whilst you are not going to necessarily find what a rivals detailed suspension settings are, down to the number of clicks and geo tweaks, when you build a car for a series and you have complete freedom on suspension it's easy to find out what suspension types, rough camber, ride heights the front runners are using and the whether they are on GAZ or AST etc. If you chose a series that has a lot of freedom on the Regs then it's going to equal big costs and for a rookie driver that maybe wants to build their own car that is a minefield of development, unless they use race proven teams or buy a car off the series with known pedigree. A big budget experience that also needs track time and experience to sort. That's why many club racing series limit both spring and damper choice for that very reason. Level playing field, keeps costs down and removes the need to keep over theorising a solution that ultimately doesn't work.
