Roxanne - budget milano/75 track car

[Andrew_TRC Mag]

Quote:

Originally Posted by AR4me Funny you should ask. Here is the story. During Saturday (and also last race at Buttonwillow), the rear would get very squirmy under braking. It was partially the reason for two spins at the entrance to Turn 9 this weekend at WSIR I had previously at WSIR run this exact same setup with Hoosiers (but without ABS) and did not have the problem. Between that WSIR event and the Buttonwillow event where it got squirmy, I put back ABS and switched to Nitto NT01. The reason for putting back ABS was that with the negative camber on the rear, the rear would lock up quite easily. With the ABS I wanted to put in insurance against lock-up since tires are costly...

[AR4me]

Hi Andrew!

That sure was a lot of questions I'll try provide some answers.

First off, yes I agree, -4 is too much. I will aim for -2 with the next Dedion - going down based on yours and Grant's comment...

Brakes are completely stock, except for pads - Porterfield RS4, fluid, and flex lines. Same pads front and rear. Hot tire pressure with Hoosiers (R-compound road legal) is 44-45 (fairly normal), while with the Nitto NT01s I run slightly lower, about 40 hot (their recommendation) - same hot tire pressure left and right. Yes, I could run an adjustable brake bias with remote, but as you also suggest, sort the basics first - the camber really seems excessive from all observations.

Yes, we run willow springs clockwise with a very high speed long right sweeper (full throttle coming down the back straight through the sweeper if you got the b...), and other high speed turns. No wheel spin out of corners, LSD is 50% and working nicely. Similar uneven wear on right rear, but the track is much more friendly to the right rear.

I have run it on 15" in the past, and it actually worked well. Too many other changes when I switched to 17" to really make a call , but I will try bring a set of 15" next time.

Thanks for the suggestions.

Jes

[Gilles]

[quote=AR4me;658295]
Yes, we run willow springs clockwise with a very high speed long right sweeper

Hello Jes,
What times are you running at WSIR?
Please let me know about your next event, I would love to see your car running.
Gilles

[AR4me]

Hey Gilles,
On the Nitto NT01s in the 1:42s on Saturday, probably about 1 sec off earlier this year on good Hoosiers. I'm looking forward to getting the rear camber into a more reasonable range, then I hope the Nittos will work really well.

Roxanne's sister will arrive next weekend, i.e. I'm going on a road trip to pick her up. I'll probably take that car out for some open testing laster this year for shake-down and to fully sort it.
Jes

[Gilles]

[quote=AR4me;660642]Hey Gilles,
On the Nitto NT01s in the 1:42s on Saturday, probably about 1 sec off earlier this year on good Hoosiers.

Hi Jess,
It seems that the NT01's don't like too much pressure, I like 39 (hot) but there are some guys that run them at 37-38 but never above 40 otherwise they start to get greasy, this pressure was recommended by the Nitto Rep and it seems to work well, you may want to give it a try

[geh458]

Quote:

Originally Posted by AR4me .....Roxanne's sister will arrive next weekend.....

[AR4me]

And a truck like yours to pull Yes, a double trailer and ability to bring both Wouldn't that be cool? I'll keep on dreaming until I win the lottery
Jes

[AR4me]

So, the next race is next weekend, and I'm trying to get Roxanne ready. Since I didn't feel like cording another rear left tire (running WSIR again), and risking a blow-out... it needed a new Dedion. Thanks to SamW I picked up a Dedion from the Greyhound station this week Thanks Sam!

While I initially thought the -4* (or slightly more) on the current Dedion was the main reason for the corded tire at WSIR last event, I learned differently today. After the event I pretty much put the car on jack stands and didn't look closer until today. Guess what, the rear left wheel bearing (corresponding to the corded tire) is shot, toast, done The hub wiggles around Now, I have no firm idea why it failed - it has probably seen 7-8 events since last replacement. I suppose suspects are the excessive camber, the 25 mm spacer...

Anyway, the Dedion from Sam gets new wheel bearings, wire-brushed, paint (a bit rusty being from GA), -2.5* camber, 4 mm toe in. Roxanne also needs rotors and pads all around. I'm hoping to get Roxanne ready, but it is going to be close since time during the week is limited. This morning I cleaned up the Dedion and dealt with frozen items on the Dedion Colin and I did one side of the Dedion this afternoon and will do the other Sunday moring. Hopefully, there is enough time to finish the other stuff.

Pics are on Colin's camera and will follow later.

The failed wheel bearing is going to add fuel to Grant's speculations regardinig rear wheel bearings - WSIR _is_ hard on the rear left...

BTW, it is going to take some time to get the 3.7 done, but that is a different story... It is on jack stands next to Roxanne and has received most of the attention lately.

Jes

[dbgrubbs]

"Anyway, the Dedion from Sam gets new wheel bearings, wire-brushed, paint (a bit rusty being from GA)"

If memory serves, that's COLORADO rust!!

[AR4me]

Quote:

Originally Posted by dbgrubbs If memory serves, that's COLORADO rust!!

[Grant]

Ouch, that sucks to hear. Rear wheel bearings aren't cheap. As you know, I'm using a 20mm spacer/adapter and I'm not looking forward to using them with some grippy rubber..

Thanks for letting us know what is going on!

[SamW]

Actually it is northern VA rust, not much salt used in CO, then it made it's way down to GA... The dedion has covered a good part of the country!!!

Hopefully it will work out for you, I put new wheel bearings in the dedion that replaced that one. Were you able to free up the spherical bearing some?

[AR4me]

Yes, spherical bearing is fine.

We finished adding camber and toe-in this morning without any issues. We have a straightforward procedure in place by now, and the most time is spent measuring, measuring, measuring, re-measuring, and re-measuring as we go along. This one was obviously done out of the car which _is_ much easier. I'll post some pics later. We ended up doing -2.7* camber and 4 mm toe-in.

But, but, but ... Everything related to the wheel bearings came apart easily, EXCEPT for the wheel bearing retaining rings. Both frozen. Even impact gun on tool made to fit the retaining ring pattern (with 1/2" socket welded onto plate). Pretty thick, but after pounding at it for some minutes it would eventually strip the "ears" on the tool We tried heating the hub. I think the last resort will be to weld a socket or plate 1/2" drive onto the retaining rings and hit it hard with the impact. But, even it came apart within 5 min, I would be out of time, unfortunately. Tired, burned out, pi$$ed, bummed, but happy to be in the recliner instead of under the f....... race car.

So, out of time - no race next weekend since I will not have time to finish it during the week due to work Oh wel...

Jes

[AR4me]

Here are some pics and information on the method that works well for us for adding camber and toe to the Dedion in a controlled manner.

First, get the Dedion on a reasonably level area and mark the location on the ground - both wheels and front Dedion pivot point.

Secondly, get your reference measurements of camber on both wheels and toe. To get exact camber, measure in reference position and rotate Dedion 180* (make a U-turn), re-measure camber of the two wheels (now in opposite positions), and average for each wheel individually. This will accommodate for a non-level work area. As you can see in the pic one wheel measured -0.6* in one position and -1.1* in the opposite position. It's true camber is then -0.85*. The target is -2.5*, and hence we need to add -1.65* - keep in mind that the camber gauge measures absolute "tilt" of wheel (surface-tilt + camber of wheel). If the wheel is worked on in the position that resulted in a measurement of -0.6*, we need to arrive at -0.6*-1.65*=-2.25*. For the toe we note the reference measurement, and divide the distance to 4 mm toe-in in two. That is the change in toe we need to add to each side.

Thirdly, we mark the Dedion sufficiently far in so that the half-shaft will not foul the Dedion after the bend has been introduced. To allow easy control of toe and camber we make a cut in the same plane as the wheel - roughly 0* camber and 0 mm toe-in.

Next, the big angle-grinder comes out. It is quite easy to get a straight cut with a single cut using a big blade, following the mark on the Dedion.

Jes

[AR4me]

Once cut, not all the way through, but to the point where it will bend with some pursuasion - don't want it too loose.

We bend it to the correct camber and check that toe is about right. It does not have to be exact. We then put a tack-weld top center. Now camber is fixed.

We then wedge in a small object, e.g. screw-driver, back or front to fine tune the toe.

As we weld up the cut we continuously check both camber and toe to make sure the heat does not distort too much. The place you weld will contract. So, you want to try get weld evenly from all sides, in some sense. You can also run extra beeds of weld to try correct final alignment if it is off. Of course, you can only correct so much.

The pictures show, in order: checking the camber (you obviously have to check camber at vertical - some camber gauges have level built in - this one doesn't, hence the home depot level), checking the toe, and the welded up cut. In this particular case we have a final camber of -2.7* and 4 mm toe-in. It is our experience that the final welding adds about -0.2* to -0.3* camber. This is natural since the cut (and hence the weld) is on the upper portion so to speak, while the Dedion is not cut at the bottom. However, the -2.7* was so close to the target of -2.5* that we decided not to correct. Had the two sides been different we would have corrected.

What is needed:
1. Accurate toe measurement tool.
2. Accurate camber gauge.
3. Big angle-grinder (we use a 10" cut-off blade)
4. Welding equipment and skills.
5. Basic trigonometry skills.

Somewhere in this thread there are pics and info from when we did the first Dedion in-car. It is quite a bit easier to do out of car.

Jes