Swapping front hubs for more caster?

[Donnie]

You could try a small plate with holes on the forward side of your extender and longer pinch bolts(effectively locking the carrier to the extention) to prevent rotation.

[Mr.Crossfire]

Yeah, I've been thinking that too. Well, to be exact I was thinking about making an U-shaped plate to cover both sides. Have been driving around a little now with the extenders installed. Gut feeling is that the body roll is now less, but I have not been pushing the car very hard, studded tires still on etc. At least the extenders have not twisted around or anything yet.

I even conducted a preliminary structure stiffness test:

http://mrcrossfire.kuvat.fi/kuvat/90q/osia/Alusta/20130330_011155.jpg

The strut was going into the bin, so I decided to sacrifice it to the science. Also in the picture is the first, aluminium(!) prototype. Jacked the weight of the car up with no problem whatsoever. Next week I'm going to test the structure with a heavy duty force sensor (up to 2,5t) and a hydraulic press. It will be tested until destruction. Btw. the shock absorber in the pic was wasted already, not bent by that experiment.

[Avantus]

After reading on weight distribution on the last pages.

I had my RS2 cornerweighted last year, and with 1/2 tank fuel that was 58/42.
I'm convinced that with some mods like aircon delete and some other stuff it should
be able to reach 55/45, which isn't that bad for a 4wd car.

[Mr.Crossfire]

Okay, yesterday it was time for some more serious testing. Here's the setup:

http://mrcrossfire.kuvat.fi/kuvat/90q/osia/Alusta/20130410_172535.jpg

I had two prototypes to test, the one in the picture is machined from aluminium, and the other one was machined from steel. Unfortunately I don't know the alloys, but I'm pretty sure that the steel one was regular S355.

Anyway, the results were such that the aluminium one bent with 1300kg load. That was really more than I would expect. The steel one bent with 2000kg, but I was somewhat surprised that the strut stayed intact! So all in all, the results were very favorable. I estimated that with the 816kg front axle mass in my 90q, with 1g lateral and roughly 80% of the load being at the outer tire the statical load would be something around 650kg. So it seems that I have a generous safety margin, considering that the real extenders machined from 42crmo4 have something like 2-3 times the yield strength compared to the regular S355. And it also seems that the original struts are also up to the task. The strut in the test was the 1-piece design, but I don't think the 2-piece design is much weaker. I will test with 2-piece strut also, but I need to aquire the parts first.

[90quattrocoupe]

I am surprised at that load, that the ball joint did not come apart.

Greg W.

[Audi_CQ]

Ready to accept orders?

[Ryss]

I think I will be interested in a set too, if the price is right.

[Mr.Crossfire]

I'll give them a spin around the track on sunday, and if I come out alive then I think I will be arranging the serial manufacturing. I have to contact the machining shop again, to see if they have time to make these. And they also said that 20pcs is the minimum quantity, so I need to see if there are some other people interested as well. Few people I know already here in Finland.

[Audi_CQ]

I'll take 4 (they fit both front and rear I assume?)

[90quattrocoupe]

I will take 6. That makes 10, half your order.

Greg W.

[my2000apb]

estimated price?

[90quattrocoupe]

I'll give them a spin around the track on sunday, and if I come out alive .............

So it is now Monday, are you still alive?

Greg W.

[vwmannen]

I would be interested i a set of 4 as well

[Mr.Crossfire]

Yes I am alive. The extenders worked fine, but the driver's side turned in its mountings under heavy braking. I have to make the bits to prevent that from happening. Other than that, the car was really fun to drive. I didn't dare to push it into extremes as this was first "summer" trackday and first time with the extenders etc, but according to the performancebox data, I managed to get something like 1-1.1g lateral (peaking at 1,2g) with practically no understeer at all. Of course it's not only due the extenders but the other modifications as well.

According to the quotes I have received from machine shops, the pricing would be something like 250-260e/pair. So a set of four ~500e or so. That would include bolts, nuts & the possible turning prevention pieces. Quite expensive due the tough material.

[90quattrocoupe]

Yes I am alive. The extenders worked fine, but the driver's side turned in its mountings under heavy braking. .

Glad you are alive. Just because we want the extenders.

Did it turn in the hub carrier or on the ball joint? The bolts in the slots didn't hold it in place? Interesting.

Greg W.