Racepace Tein Vs Others

[Roy]

Lol they do...we just need to be a little innovative. What size are you after?

[djr81]

Well it depends. I have a Whiteline front which is about right and a Cusco rear (fixed) which is too stiff. Was contemplating some more neg camber for the back to grip it up but my gut feel is I have too much stiffness back there. Will pull the front bar up and see how it upsets front grip. It used to be all ok until I put some different oil in the rear diff and now it turns like the diff actually works - which means oversteer.

On another topic what diameter springs do the MCA use?

[djr81]

May be the answer here:

http://mint-design.ca/2013/04/

Just wonder if the sway bar is spring steel or mild steel?

[niZmO_Man]

It should be spring steel shouldn't it?

[GTSBoy]

It's a spring......

[djr81]

Its hollow. You find me some hollow spring steel in 30mm od and 20mm id. I don't think there is such a thing.

[Ben C34]

You show me mild steel that won't snap after being flexed repeatedly.....

[GTSBoy]

I had always assumed that hollow ARBs were spring steel, the same as any other spring. A decent manufacturer of these things would either buy hollow material of the right composition and the de-temper it so they could form it, then re-harden and re-temper it to make it a spring again, same as they do for coil spring winding. If it is not possible to buy such material off someone's shelf, then I would have assumed that a decent manufacturer of such products would forge their own (admittedly, that's outside my abilities to imagine how they'd do it, but then so is most mechanical engineering going back to the blacksmith days!).

But at this point I have to ask why hollow bars are such a big necessity for you? You need a larger diameter hollow bar to achieve the same stiffness as a solid bar, especially if the solid bar is made from springier stuff. And the weight saving associated with having a hollow bar over a solid, is what? A couple of kg max? Almost all of which is sprung weight anyway. Seems easier places to get a small weight saving out of a car.

[djr81]

A solid 27mm bar is 4.5kg/m.

A 30/20mm bar is 3kg/m.

They are thereabout the same stiffness (Hollow 5% more).

So 3kg for the rear. Maybe another 2 for the front. Its all weight.

Just cant find an obvious answer to the question and material testers can only do so much.

[Roy]

Doesnt matter what the bar is...just use some 450 mild steel bar nachuned flat on two sirfaces and turn down the end to the id of the tube diam.

Then do a full pen but weld...wouldnt hurt to dowel or plug weld a 4mm pilot hole through the bar-insert just for insurance

[warps]

And ffs blend / peen the welds when you finish. For a little bit of extra work you almost eliminate crack initiators.

There are plenty of grades of steel between "mild" and "spring" (note neither of those have an actual standard defining what they are - they are more of a colloquial / marketing term). You can get higher yield strength steels by varying carbon and other alloying elements, and also give good heat treatability to allow the forming / tempering process.

Mild steel will flex within its elastic range forever. The reason that "spring" steels are used is to allow the spring to deform much further (higher strain) and remain in its elastic range. You'll find that the steels all have about the same modulus of elasticity. The main difference is the yield strength.

[djr81]

Yeah the spring steel - atleast the old school Australian AS1447 XK5155S & XK5160S have defined ranges of alloying content. As do any number of other grades down to your common or garden 250MPa yield strength mild steel. Just a matter of guessing what the bar would be made out of and matching that. Radiusing is good, haven't seen stress relief by belting It with a hammer for a long time but is a good method none the less.

[warps]

Yeh that was the point - you don't need to be chasing this magical spring steel. Plenty of other grades that can do an effective job of it.

Peening can be easily done with a needle gun - its fairly standard practice for crack repairs in high fatigue areas and critical welds (boom welding etc.). It's almost become second nature to boilies I my industry. They used to use the guns to chip the slag off, but now with gas and wire feeeders, they use the guns more for peening than getting rid of slag.

Of course as soon as you start welding onto the spring steel, you'll probably gain more from correct pre / post heat than peening or blending. Not something I'd be recommending your average backyarder with a Bunnings gasless MIG setup.

[Snowman]

I recall Snowman on here went from RPM built Teins to full house MCAs and the car was worse but after some tuning and tweaking the thing was equally epic...winning Targa in his 34.

What the net gain was going to full house MCAs after purchase, rebuilding and development was over the Teins????

There was no doubt the overall net gain on the MCA's was up over the RP Teins (you would hope so given they were more $$$). That said the MCA's were no walk in the park to set-up to get those gains. In fact with very small changes in bump or ride height they were worse than the RP Teins. When we went from the blue R34 to the white one with the same set of shocks it took me 6 months to re-find the sweet spot on the MCA's just due to the change in overall weight and weight distribution in the two cars. And I'm talking a change of 2s / km with no other changes to the car other than getting the bump and ride height settings right.

My experience with the RP Teins was they had a much broader sweet spot which made them a great shock whether you were at PI, Sandown or Targa without having to change anything on set-up - where as the MCA's could get you and overall net gain, but only if you dialed the shocks in exactly right at each different place. So if you were comfortable in doing that the MCA's were ahead - if you wanted a set and forget shock then the RP Teins were the winner.

[niZmO_Man]

^ Good insight.

[Snowman]

Another thing many people don't appreciate is how much actual change in compression is generated by the little knobs on the top of the shocks.

If you put the RP Tein shocks on a shock dyno and change the setting from full soft to full hard you might only see a 2% total change in value. These shocks through years of development have the valving and stuff nutted out to work well with these cars which is why when pretty much anyone bolts them in they work well and really clicking the knobs is just fine tuning personal preferences.

In something like the MCA's the difference between full hard and soft can be 10% total change and that is why they can be much trickier to get set up correctly. You look at the full top of the range stuff like the full race products from Ohlins, Sachs, Supashock (what I now use), KW etc and that number can be even higher.

But this is one of the reasons why these "race" shocks cost more.

It has positives and negatives. I know I needed the help of Steve Glenney to get my MCA's dialed in properly but it was a great learning experience of what compression, bump, ride height all effect on a cars behaviour.

[vesh]

Thread revival...

I currently have Tein RS coilovers in my R33 GTR (Racepace Spec) and find them ridiculously hard. On the other hand the Tein RA coilovers (Racepace Spec) in my race car are perfect.

I am looking at purchasing some new suspension for my street car. Looking at either the Bilstein B16 or MCA XR Red series.

Does anyone run either of these in their car?

[JGTC]

I was in a similar boat 6 months ago, i had narrowed it down to Bilstein PSS9s and MCA Reds as they were able to be serviced in Aus.  Other options were KW V3 and Ohlins DFV/R&T which have limited support in Aus.

I went with MCA Reds, valved for hillclimb/tarmac rally (ie. street surface), spring rates were 12kg front / 5kg rear, they have been great on sydney roads, more compliant at the speed limit than the stock M-spec suspension that came with the car, but at the same time doesn't bottom out in crests and is noticeably more stable under braking and turn-in when moving quickly.

From all accounts they are more comparable to the Bilstein Clubsport package which is $5K+which provides custom valving and spring rates, the PSS9 coilovers are a factory preset to suit the model of car (which is also no doubt research and a good balance for street/track)

Below is some feedback i got from talking to Heasmans and MCA during my search;

 

[Roy]

On ‎23‎/‎11‎/‎2016 at 11:46 AM, vesh said:

Thread revival...

I currently have Tein RS coilovers in my R33 GTR (Racepace Spec) and find them ridiculously hard. On the other hand the Tein RA coilovers (Racepace Spec) in my race car are perfect.

I am looking at purchasing some new suspension for my street car. Looking at either the Bilstein B16 or MCA XR Red series.

Does anyone run either of these in their car?

Have you asked the question why there is such a difference between your street car and your RS and RA? They are a similar shock so imagine there is either something in the springs you are running or perhaps the RS are still std valving as they come from Japan? It would be worthwhile asking the question.

They definitely are a good solution as they work well on the street and can be made to work quite well on the track to!