TTX25 Dampers - experiences

[Steve Slowboy]

Hi All,
I'm new to this forum - stumbled across it whilst investigating dry sump systems for my hill climb car.
My car is slightly different to the ones you all build, but is still a motorbike engined single seater;

It's called the PCD Saxon - a carbon tub'd single seater hillclimb car fitted with a GSXR1100WP motorbike engine. Full wings and slicks and weighing it at 224kg and with over 200hp.

I'm in the process of investigating replacing the rear dampers to gain adjustability in order to improve the traction and weight transfer capabilities - it's currently fitted with modified formula V Penske (non-adjustable).

The problem I have is space and weight - there's not much about "off-the-shelf" that would fit the bill and be affortable!

I stumbled across Warwick uni's formula student car at this year's Autosport Show and spotted the tiny Ohlins TTX25 dampes they use. I got speaking to the chaps on the stand and then chatted to the guys on the Ohlins stand.

The TTX25's appear to be an almost perfect solution for me - offering a huge range of adjustability, suitably compact and light weight, and most of all - affordable. "Normal" 4-way adjustable dampers are serious money and way to big.

I was kindly sent up a demo unit from Auroc to check fit, and along with my attempts at superimposing the CAD file onto my car drawings, it's all looking very do-able.

So, my questions for you folk that have used these are what are they like to live with?
Do they last the distance? What's their reliability like? How easy were they to dial in?
Any other comments or concerns?

All help greatly appreciated,

Cheers
Steve

[acedeuce802]

Unfortunately, I cannot comment on these dampers. But, do you have any pictures or videos of your car?!

[PatClarke]

Steve,
You have the Saxon? That is a really nice car with a very good pedigree. Is that not the car designed by Martin Ogilvy?

The shocks you speak of also come brandes as 'Cane Creek' and are probably the damper of choice for most serious FSAE competitors! Very good dampers indeed!

If you can get yourself to FS at Silverstone in July, you will see many applications of these dampers and can talk with some very smart young students who are using them!

If you get there, look me up and I can introduce you to whoever you might want to meet.

Cheers

Pat

[mdavis]

We've been using the ohlins ttx25's for many years now (in their other form as the cane creek's since 2007). They're great dampers. Very low hysteresis, and like you said, a very wide range of adjustability. We've had 1 problem with a damper failing and that was more due to user error (team members being stupid is honestly the only thing I can come up with) where we tore up the aluminum manifold. We still have the original dampers on our 07/08 cars, and they got used a lot, even after the 2-3 competitions they went to.

[SNasello]

The current version of the Ohlins fsae dampers are valved pretty soft compared to the original cane creek. There has been a few revisions to the damping curves over the years, so make sure you get the ones you want. The fact that the car only weighs 224kg means you can probably use the newest version, TTX mkII without problems. Just make sure that pick the right motion ratio when installing them. Otherwise the range will be too huge and you will end up with too big of a span between each click.


The range of adjustment is very large, perhaps too large. The biggest problem with setting them up is trying to go by the damping curves that you are provided with. They do not give a very good idea of the effect of low/high speed adjustments. I would suggest getting one of them dynoed with different low/high speed combinations. This will be invaluable.

[Jon Burford]

the Saxon is such a beautiful car, I would love to drive one!
We run the TTX dampers, we like them. I would as advised have a look at the bare Cane Creek units as they will save you a lot of money!
We will be at Silverstone, come find us if you make it up there.

[Steve Slowboy]

Thanks for the feed-back! Nice to hear that the TTX's are holding up ok. Our UK hills are pretty short (generally less than 50 seconds driving0 but I don't intend to have to replace them for a while!

It is the MkII's that I'm looking at and will most likely need to make up extended top-eyes to fit the car, along with getting some springs wound for me as the car runs 120 lb/ft springs at the moment.

The motion ration is 1:1 so hopefully no worries with the possible settings, though I'll try and get an approximation of damping based on the dyno curves of my Penskes (though their low-speed damping is pretty poor).

Adam - if you look at zipp.co.uk and search for PCD Saxon there are a few photos taken by Rich Danby at a few of the British Hillclimbs I was at last year. Also search for PCD Saxon on you-tube - I've uploaded a few onboard videos, though without the data overlays. (I run with a Chasecam PDR100 and DM10 data logger - which has GPS, g-force, revs and oil pressure logging). With the sticky hillclimb Avon radial's i regularly see over 2 g cornering forces.

Pat - yep, it is the Martin Ogilvie designed car - I've bought the complete car, all moulds and the design rights for it. I'm in regular contact with Martin and he's currently looking at the installation of the Ohlins for me so hopefully will come up with a sensible solution - especially difficult as the stroke is limited compared to the Penske's so I'm going to have to be careful how I install them to maintain adequate droop and bump.

Jon - there were only ever two Saxon's built - and the other one is in the Lane Motor Museum in Tennesee in the US, so it's unlikely you'll ever get to drive one! It's a pretty compact car and fits me like a glove so if you're much over 11 stone and 5'7"" you're unlikely to fit in it!

Cheers
Steve

[Kevin Hayward]

Steve,

The PCD Saxon was our inspiration for the 2003 UWA car (and onwards). We repurposed many of the design ideas, particularly the wheel-hub-brake setup and the chassis/suspension layout. I regularly look over pictures of it as a design comparison.

Not much more than 200kg with a considerably larger engine and an aero package. There is lots to learn from that car when designing FSAE vehicles.

Kev

[whiltebeitel]

Steve, for your spring rate range, an option the the Tanner Orange Hot series springs. We've measured them to be pretty accurate for spring rate and come in 5 lb/in increments right in the range you use.

[Steve Slowboy]

I had a look at the Tanner range of springs, but it's not clear what the ID is - some quote 34mm and some sites quote 1.625".

Does anyone know for sure if they are available in 36mm ID?

Cheers
Steve

[Crispy]

These Tanners (http://pitstopusa.com/i-5070913-tanner-orange-hot-quarter-midget-spring-120-lb-5-tall.html) are 1.63" ID. We use them, as well as the equivalent Eibach springs on our Penske 7800s (the red quater midget shock).

I don't recall ever seeing quarter midget springs (Tanner of Eibach) on the TTX/Cane Creeks. I think you would need custom perches if you wanted to use them, although I'm not certain. I'm also not certain about the clearance between the spring and reservoir.

[whiltebeitel]

Originally posted by Crispy:
These Tanners (http://pitstopusa.com/i-5070913-tanner-orange-hot-quarter-midget-spring-120-lb-5-tall.html) are 1.63" ID. We use them, as well as the equivalent Eibach springs on our Penske 7800s (the red quater midget shock).

I don't recall ever seeing quarter midget springs (Tanner of Eibach) on the TTX/Cane Creeks. I think you would need custom perches if you wanted to use them, although I'm not certain. I'm also not certain about the clearance between the spring and reservoir.

When we have used them, we do have a pair of small aluminum rings the take up the difference on the TTX25 perches. There is no issue with spring to reservoir clearance.

[Luniz]

On the drawing it says ID should be 36.30mm +0.50
http://zupin.de/uploads/tx_use...ads/db_springs_s.pdf (http://zupin.de/uploads/tx_userzupindownloads/db_springs_s.pdf)

We have been using H&R springs with an ID of 36mm since the last 3 years and as they sponsor quite a lot of teams, they already have a large variety of springs this size, some of which are custom wound for fsae teams. They even have helper springs in this ID.

I'd suggest you give them a call for the exact list of exact spring rates...

[Steve Slowboy]

Luniz,
Thanks - I'll look into the H&R springs as an option. I'm very tight for space so the Tanner one's won't fit.

The car's designer had come back with a suggestion to change the rockers (motion ratio) to regain the suspension travel. He also advises against using very long extension top-eyes due to side loading, so has suggested a revised lower damper mount to compensate.

Basically, I'll need to get new rockers, new top-eyes and new lower mounts machined up. This is beyond the capabilities I have in my garage so will have to outsource this once I've tidied up the drawings.

I'll keep you posted, but I will be going down this route as the Ohlins do seem to me to be the perfect choice for the Saxon.

Thanks for all the advice folks,

Steve

[Ceboe]

Hi,I'm looking at buying these dampers for our next car but I'm struggling with the measurements I can find online.

They say the damper has a free length of 200 mm with a stroke of 57 mm.
Does this mean that when the damper is half compressed, the length of it will be 171,5 mm? (200- 57/2= 171,5)
Thus having 28,5 mm of travel in both directions?

[jlangholzj]

Originally posted by Ceboe:
Hi,I'm looking at buying these dampers for our next car but I'm struggling with the measurements I can find online.

They say the damper has a free length of 200 mm with a stroke of 57 mm.
Does this mean that when the damper is half compressed, the length of it will be 171,5 mm? (200- 57/2= 171,5)
Thus having 28,5 mm of travel in both directions?

How i interpret it: total of 200mm of length with an allowable 57mm stroke. total closed length of 143mm.

[old soldier]

Hi?I come from a China FSAE team named HRT,we have used CCDB in 2011 and TTX25 in 2012,but It seems that I didn't know to adjust it to best condition,Do you have any good ideas to share with me? Thank you!

Originally posted by Jon Burford:
the Saxon is such a beautiful car, I would love to drive one!
We run the TTX dampers, we like them. I would as advised have a look at the bare Cane Creek units as they will save you a lot of money!
We will be at Silverstone, come find us if you make it up there.

[old soldier]

Hello Kevin
It my fist time hear The PCD Saxon?If you can provide some detail photo of it?I want to learn the design of it for our 2013 racecar.Thank you!

Originally posted by Kevin Hayward:
Steve,

The PCD Saxon was our inspiration for the 2003 UWA car (and onwards). We repurposed many of the design ideas, particularly the wheel-hub-brake setup and the chassis/suspension layout. I regularly look over pictures of it as a design comparison.

Not much more than 200kg with a considerably larger engine and an aero package. There is lots to learn from that car when designing FSAE vehicles.

Kev

[Owen Thomas]

I didn't know to adjust it to best condition,Do you have any good ideas to share with me?
Ohlins has damper dyno plots available on thier website (http://www.ohlinsusa.com/ohlins-ttx-25-fsae), as well as a wealth of other information. You can use this and your intended suspension frequencies (ride & roll) to get a baseline setting for your vehicle. The rest is engineering.

[HenningO]

Originally posted by jlangholzj:
How i interpret it: total of 200mm of length with an allowable 57mm stroke. total closed length of 143mm.

Remember that the end-eye on the TTX25 (like on many other dampers) is just threaded onto the shaft. If you are struggling with packaging/rocker interference it's a pretty straight forward task to manufacture one yourself with whatever dimensions you want.

[jlangholzj]

Originally posted by HenningO:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by jlangholzj:
How i interpret it: total of 200mm of length with an allowable 57mm stroke. total closed length of 143mm.

Remember that the end-eye on the TTX25 (like on many other dampers) is just threaded onto the shaft. If you are struggling with packaging/rocker interference it's a pretty straight forward task to manufacture one yourself with whatever dimensions you want. </div></BLOCKQUOTE>

It sounded like he was struggling with understanding ohlins specs...for some reason...Just was clarifying what appears on ohlins drawings and website

[Steve Slowboy]

Old Soldier,

If you google PCD Saxon images, you'll find loads of photos of it in action in 2011 and 2012.

I'm in the middle of a complete strip down and rebuild in the off-season. The tub is getting repainted, a new gear cluster from Nova and a new paddleshift control ECU as the old one was problematic and helped in wrecking my gear box. I've pretty much replaced the whole wiring harness as well - to suit the new gearchange ECu and to reduce weight.

I haven't got round to doing the TTX dampers - yet! funds were severely depleted having to replace the gearbox....

Cheers
Steve