Ohlins Camaro

[Abdi]

Originally Posted by Burt

I haven't found any "rules of thumb" on rake, other than that more rake encourages turn-in, up to the point where it makes the car unstable. I have a friend who has a lot of track experience (110+ track days, talks directly to manufacturers to make adjustments) and on everything from his Miata to his Viper ACRs, rake encourages response. In a sense, you're statically loading the car in the same way as when you trail brake, and lessening the roll moment in comparison to the front.

In the case of the Ohlins suggested ride height having some rake in it I'm pretty optimistic they tested and found that this was a good way of altering the balance of a Camaro. All things being equal it's been my experience that rake traditionally has been more or tuning tool for high speed aero dynamic balance of the car. That not to say that there is no mechanical grip benefits to having some rake. I'm no engineer so I'll quote a couple of my trusted sources for how rake alters the balance of the car.

"Rake can be used to change the balance of the car by altering the roll axis, the line between the front AND rear roll centers. True "level" rake is not measured by the wheel gaps or anything like that, it's the roll axis. The roll axis is simply the axis the car rolls around, with the roll couple being the a function of the distance from the COG and the roll center. The larger the roll couple, the more roll. The roll couple is a moment arm....for a given cornering force, the farther the COG from the roll center, the larger the moment."

"Start with a level roll axis, and lower the front of the car, and you usually end up with a greater roll couple up front --> a shift towards oversteer."

"Balance and grip are easier to tune with good spring, swaybar, and damper rates as well as a dialed in alignment. And you need to do this anyway first. If you have coilovers, it's a fun thing to play around with and you can find a nice solution (but remember to check alignment after every ride height change). It's nice to plot the roll centers and use that to determine your rake, but always remember what you're doing to other parts of the car with certain set-ups."

[Fondue Wormhole]

Originally Posted by Burt

I haven't found any "rules of thumb" on rake, other than that more rake encourages turn-in, up to the point where it makes the car unstable. I have a friend who has a lot of track experience (110+ track days, talks directly to manufacturers to make adjustments) and on everything from his Miata to his Viper ACRs, rake encourages response. In a sense, you're statically loading the car in the same way as when you trail brake, and lessening the roll moment in comparison to the front.

Well, it's not really the same. One problem is, especially on a Mac strut car, you don't know where the roll centers are going. With a Mac strut you can actually increase the roll moment the lower you go.

I tend to not focus on what other people are doing; I think it's a REALLY bad idea, but if you're friend is fast, and he runs rake, then have it...


As far as the Ohlins dampers and helper springs, I was very careful with my choice of words:

Originally Posted by Fondue Wormhole

You MAY be able to go lower by incorporating a helper spring; you'd just have to look at the numbers...

The whole point was: the ride height is adjustable, it just may not be as adjustable in the direction you want with that much rate. If they didn't want the ride height to be adjustable, they would have welded perches in place like the OEM dampers.

You can be too far into the stroke at static height, and conversely, you can be too high in the stroke. I've seen some Camaro corner weights showing 100 pounds difference between front tires. With a 1:1 ratio (close enough) and your 400 lb/in spring, there's 1/4" difference right there.

That's why you look at numbers, and don't guess, or assume. Obviously the guys at Ohlins have worked this out, and their recommended preload is certainly where you'd want to start, but it's not an absolute; it's a starting point...

[Abdi]

Originally Posted by Fondue Wormhole

Well, it's not really the same. One problem is, especially on a Mac strut car, you don't know where the roll centers are going. With a Mac strut you can actually increase the roll moment the lower you go.

I tend to not focus on what other people are doing; I think it's a REALLY bad idea, but if you're friend is fast, and he runs rake, then have it...

That is a great point!

As with many Mac strut cars, as the front comes down, static negative camber is lost, and toe in is gained and this by itself it not worth the sacrifice only to gain some rake.

Originally Posted by Fondue Wormhole

As far as the Ohlins dampers and helper springs, I was very careful with my choice of words:


The whole point was: the ride height is adjustable, it just may not be as adjustable in the direction you want with that much rate. If they didn't want the ride height to be adjustable, they would have welded perches in place like the OEM dampers.

You can be too far into the stroke at static height, and conversely, you can be too high in the stroke. I've seen some Camaro corner weights showing 100 pounds difference between front tires. With a 1:1 ratio (close enough) and your 400 lb/in spring, there's 1/4" difference right there.

That's why you look at numbers, and don't guess, or assume. Obviously the guys at Ohlins have worked this out, and their recommended preload is certainly where you'd want to start, but it's not an absolute; it's a starting point...

I agree with you completely and did notice your choice of words. My previous Ohlins R & T rear coilovers on my STi used a helper spring and it is was for the very reason you mentioned above.

I'm looking forward to seeing the initial ride heights when we put it on the scales and see where we end up after it's full alignment.

[Notilloc]

So. . . . I'm dying to hear how they were on the track!

[Abdi]

Unfortunately, my summer plans have changed significantly since I've had two short notice trips for work. I'm active Air Force, and I've been home for a week. I'm not giving up on it though we still have three months of decent weather.

I have about 1,000 miles on them so far on the street plus and one auto-cross with New England SVT club and I can tell say that I'm usually grinning ear to ear ever since I installed the R&T's. At lowers speeds (10-35mph) the car is not as compliant as the OEM FE6. At speeds above 45mph the new found bandwidth for road imperfections and the precise response of the car as the weight transfers from the front and rear or side to side makes the car a lot more fun to drive. During the auto cross I set the knobs 7 clicks from full stiff at all four corners and drove that way for the rest of the day. I never fell like I had to make any more adjustments. My driving was the only thing needed the adjustment.

These are the real deal a very decent balance for daily driving and serious track worthiness. They are not perfect for one or the other but for my use they are exactly what I was looking for.

One thing to consider for those of you with aftermarket anti-sway bars or end links. The R&T's have a 12MM hole for the front end-links like the FE6. It is very hard to find aftermarket 12MM studded end-links or at least that's been my experience. The DSE links did not workout for me as those have 10MM studs which are designed for the JRI/DSE set ups. I've since been able to find a very reputable suspension manufacturer to make the end-links for me with 10MM studs for the DSE anti-sway bar connection and 12MM studs for the bracket on the Ohlins.

Apparently I was one of the first to purchase these and I received an email from an Ohlins R&D technician asking if I have had any issues or if I wanted to give them any feedback on where I thought there might be room for improvement. I suggested that they make an in house camber plate available and made them aware of the end-link hole size which can be the cause for front suspension clunking if the consumer is not aware. They offered to service and revalve them for me once a year every year and I can also request different springs rates if I wish. All of that makes me a happy customer.

Cheers,
Abdi

[Notilloc]

Originally Posted by Abdi

Unfortunately, my summer plans have changed significantly since I've had two short notice trips for work. I'm active Air Force, and I've been home for a week. I'm not giving up on it though we still have three months of decent weather.

I have about 1,000 miles on them so far on the street plus and one auto-cross with New England SVT club and I can tell say that I'm usually grinning ear to ear ever since I installed the R&T's. At lowers speeds (10-35mph) the car is not as compliant as the OEM FE6. At speeds above 45mph the new found bandwidth for road imperfections and the precise response of the car as the weight transfers from the front and rear or side to side makes the car a lot more fun to drive. During the auto cross I set the knobs 7 clicks from full stiff at all four corners and drove that way for the rest of the day. I never fell like I had to make any more adjustments. My driving was the only thing needed the adjustment.

These are the real deal a very decent balance for daily driving and serious track worthiness. They are not perfect for one or the other but for my use they are exactly what I was looking for.

One thing to consider for those of you with aftermarket anti-sway bars or end links. The R&T's have a 12MM hole for the front end-links like the FE6. It is very hard to find aftermarket 12MM studded end-links or at least that's been my experience. The DSE links did not workout for me as those have 10MM studs which are designed for the JRI/DSE set ups. I've since been able to find a very reputable suspension manufacturer to make the end-links for me with 10MM studs for the DSE anti-sway bar connection and 12MM studs for the bracket on the Ohlins.

Apparently I was one of the first to purchase these and I received an email from an Ohlins R&D technician asking if I have had any issues or if I wanted to give them any feedback on where I thought there might be room for improvement. I suggested that they make an in house camber plate available and made them aware of the end-link hole size which can be the cause for front suspension clunking if the consumer is not aware. They offered to service and revalve them for me once a year every year and I can also request different springs rates if I wish. All of that makes me a happy customer.

Cheers,
Abdi

Nice! Thanks for the update!

[cdb95z28]

Any new updates?

[fastbroshi]

Originally Posted by Abdi

They offered to service and revalve them for me once a year every year and I can also request different springs rates if I wish. All of that makes me a happy customer.

Cheers,
Abdi

That was great of them to offer that. I wonder if services like that come with shocks of that caliber and we just don't know it.

[JusticePete]

Originally Posted by fastbroshi

That was great of them to offer that. I wonder if services like that come with shocks of that caliber and we just don't know it.

They do, but not for free.

[SS Performance]

I know its been a few years but I was wondering what your thoughts are after all this time.

Do you still have the Ohlins? Did the springs droop any?

I am looking at the Ohlins and was wondering.

Thanks
Craig