Raceland Dyno Test Results
#44
Junior Member
Thread Starter
Join Date: Jun 2008
Location: Fairfield, California
Posts: 436
Total Cats: -7
To a degree the concept is actually growing on me....a bit. And I do like the idea of installing something decent within a protective shell of a sort. I'm just not impressed with the insert they used, though I recognize they are building to a price point.
I have to admit, though, that not being as familiar with shocks as you are, I was completely surprised that there was another little shock inside what I thought was the shock. Learn something new every day.
#47
It's a little different for the Miata guys than the BMW guys. The BMW guys have to use inserts due to the strut style suspension unless they want to spend a little more. The idea of putting a monotube inside of a tube and then mounting that instead of just mounting the original monotube would only be for when you need to "hide" a shock (cheater). This is not as uncommon as you would think. A lot of oval track series have spec twin tube shocks, so the best way to get a rebuildable shock is to hide it in the gutted twin tube body.
#48
I will be posting all of the data on these shocks, along with pictures, later today.
For the individuals that want to get really detailed on the data, I suggest you download the Roehrig dyno software. Here is a link: http://roehrigengineering.com/Downlo...ads%20page.htm
Download the software and install in demo mode. I will post the data file and the software will allow you to see the shocks in full detail with all available graphs.
For the individuals that want to get really detailed on the data, I suggest you download the Roehrig dyno software. Here is a link: http://roehrigengineering.com/Downlo...ads%20page.htm
Download the software and install in demo mode. I will post the data file and the software will allow you to see the shocks in full detail with all available graphs.
#49
The main issue, is there's very little shape to the curves. The actual stiffness is an issue on the rear rebound, but the more important element is the shape of the curves.
The rebound is pretty much a linear line, which would suggest a piston that's allowing a lot of bleed around it rather than through it. That's poor design/manufacture/components.
Bump is similar, but clearly has a knee point where the curve 'blow-off' from the initial rate. Still, there's potential for a more low speed bump to keep those stiff springs under control for traction.
If you're interested, there's some useful stuff here: http://www.optimumg.com/OptimumGWebS...Tech_Tip_4.pdf
The rebound is pretty much a linear line, which would suggest a piston that's allowing a lot of bleed around it rather than through it. That's poor design/manufacture/components.
Bump is similar, but clearly has a knee point where the curve 'blow-off' from the initial rate. Still, there's potential for a more low speed bump to keep those stiff springs under control for traction.
If you're interested, there's some useful stuff here: http://www.optimumg.com/OptimumGWebS...Tech_Tip_4.pdf
#50
Please don't get too excited about this. There is still a lot that the dyno doesn't show. Remember when I told you guys that you can build two shocks that look the same on the dyno that will not react the same on the vehicle.
Not all linear graphs mean a linear piston. You can valve a digressive piston with a lot of bleed and it will look like a linear, as in the case with some Bilsteins.
Not all linear graphs mean a linear piston. You can valve a digressive piston with a lot of bleed and it will look like a linear, as in the case with some Bilsteins.
Last edited by Bernie S.; 12-05-2010 at 03:22 AM.
#51
Please don't get too excited about this. There is still a lot that the dyno doesn't show. Remember when I told you guys that you can build two shocks that look the same on the dyno that will not react the same on the vehicle.
Not all linear graphs mean a linear piston. You can valve a digressive piston with a lot of bleed and it will look like a linear, as in the case with some Bilsteins.
Not all linear graphs mean a linear piston. You can valve a digressive piston with a lot of bleed and it will look like a linear, as in the case with some Bilsteins.
I read your earlier comments suggesting there are attributes that the shock dyno doesn't show. I'm still trying to get a handle on that. Perhaps when I see the raw data it will make more sense.
#52
Just because the rebound curve appears alright, that doesn't mean it is. It depends on how they achieved the valving. If they used a linear piston, sure. If they used a digressive with a lot of bleed, then that is sort of old school and common with production units to cover flaws.
Picture a shock where the piston doesn't have any shims, only ports/holes. When the shock changes direction, there is nothing really controlling the low speed.
Even with the raw data, you can't confirm the valving for sure until you open the shock up.
Picture a shock where the piston doesn't have any shims, only ports/holes. When the shock changes direction, there is nothing really controlling the low speed.
Even with the raw data, you can't confirm the valving for sure until you open the shock up.
It will be interesting to view the more complete data when you get it. My point though, was the linear curve shown isn't bad, as PhilMD seemed to suggest. The curve alone (other than the rebound issue) isn't a reason to denigrate them.
I read your earlier comments suggesting there are attributes that the shock dyno doesn't show. I'm still trying to get a handle on that. Perhaps when I see the raw data it will make more sense.
I read your earlier comments suggesting there are attributes that the shock dyno doesn't show. I'm still trying to get a handle on that. Perhaps when I see the raw data it will make more sense.
#56
My opinion isn't quite as contrary to yours as you might think.
To a degree the concept is actually growing on me....a bit. And I do like the idea of installing something decent within a protective shell of a sort. I'm just not impressed with the insert they used, though I recognize they are building to a price point.
I have to admit, though, that not being as familiar with shocks as you are, I was completely surprised that there was another little shock inside what I thought was the shock. Learn something new every day.
To a degree the concept is actually growing on me....a bit. And I do like the idea of installing something decent within a protective shell of a sort. I'm just not impressed with the insert they used, though I recognize they are building to a price point.
I have to admit, though, that not being as familiar with shocks as you are, I was completely surprised that there was another little shock inside what I thought was the shock. Learn something new every day.
The revelation of the inserts will be nice for long term service. I'm doubtful we'll get a forum correct insert in there for performance. But then again....they are $300 CO's I just don't care.
ya left my best line out :(
These shocks have yet to surprise me. I got exactly, if not more than I paid for.
#57
Funny you should say that. I still haven't decided if I'll install them when they come back from Bernie. I might....just to be able to follow up on how they "feel" in the vehicle. In the meantime, I've become more and more enamored by the Xida's 949Racing is selling. They are an additional $200 if you want them with helper springs. You know what I'm thinking...."Are these the same coil diameter? Do I already have a perfectly good pair of Raceland helpers?"
#59
Junior Member
Thread Starter
Join Date: Jun 2008
Location: Fairfield, California
Posts: 436
Total Cats: -7
Those shims can be tuned to open and blow off pressure by the tuner. At low speeds they can be set to stay put, forcing the shock fluid through the bleed hole. When a large hit occurs (high speed event), the pressure spike forces the shims to deflect which opens additional ports. The damping curve now follows a different slope.
More or less bleed, and how it is combined with the control provided by the shim stack and piston ports, can sometimes mean shocks will have roughly similar plots but will arrive at those plots using different components.
#60
Please don't get too excited about this. There is still a lot that the dyno doesn't show. Remember when I told you guys that you can build two shocks that look the same on the dyno that will not react the same on the vehicle.
Not all linear graphs mean a linear piston. You can valve a digressive piston with a lot of bleed and it will look like a linear, as in the case with some Bilsteins.
Not all linear graphs mean a linear piston. You can valve a digressive piston with a lot of bleed and it will look like a linear, as in the case with some Bilsteins.