818r ncm msp

[Mitch Wright]

mitch car.jpg
No video yet but car does look good on track

[Rob T]

Mitch. Looks great. I'd love to see some performance specs from your day. Let's see how these cars are working t the track. Rob

[AZPete]

It looks like a calendar shot to me!
ah,
ah,
ah,
Performance is not important, it's all about looks!

[Mitch Wright]

Rob, have a clutch hydraulic/TO bearing problem I am sorting out. Only got a few laps in before it started acting up again, pulling the trans this weekend to see what is going on.
Pete it would be a good shot other than the blue peices of tape around each wheel that I make set change notes on. Photo shop lol

[DanielsDM]

Good to see it out on the track!

[Pearldrummer7]

Awesomeeeeeeee. More high res pics! NCM looks like a sick track

[Mitch Wright]

Finally got a break with weather and work schedule and got the car back out on track yesterday after a front spring and rear wing angle change. Will get the data down loaded today but pleased with progress and feel of the car. Running the 3.2 mile track had a best time of 2:07.8 which is more than competitive in NASA ST2. Going to make a change on the rear toe trying to make the car more comfortable in a few spots. Driver needs to get more comfortable and more consistent.
Was seeing 130mph in a few place now, last time out top speed was 125-6.

Sorry no video, but will make sure I have the camera on next time out.

[Hindsight]

That's awesome!! Do you know what Spec E46 BMWs run at NCM? Trying to gauge lap time based on that since I'm pretty familiar with their performance level.

Are you adding more rear toe? I am guessing you stiffened the front springs a bit? Are you running a front sway bar? From the pic above (from last year), it looks like you are getting a lot of body roll.

[Mitch Wright]

Correction, browsing through the date log my quickest time Thursday was 2:09:8 not 2:07 that I saw on the dash, must have been a ghost.
I don't believe we have had any of the quick Spec E46 cars visit us yet, the March NASA race the quick time was 2:28.3 I would think they should be in the high teens. A NP01 gets around in the 2:13's and Spec 944 2:27 and Honda Challenge 2:23.

Yes I added rebound front and rear, went from 5* to 2* of wing then the spring change 300#-350#(top speed increased 6 mph in part to improved exit speed and reduced drag) Looking through the data log today I was seeing 133.5 mph in a couple of place on the track, 127 was the top speed before this last time out. I have not installed a front bar, I do have one mocked up .750 .065, 083 and .095 wall 4130 to finish. I am waiting on the slide clamps and bar mounts to arrive.
Chin Motorsports is here this weekend I am going to try to get the car back out Sunday run a for few laps then try a little more rear toe in then the 400# springs.

Right now the car has zero understeer anywhere on our track, I would like to get the car to push some then back it up to just touch of corner entry push on the high speed corners.

[johngeorge]

Hi Mitch, adding front bar will add grip to the back, inducing slight understeer. Might be just what you are looking for and also with the added bonus of controlling the roll, seems like a lot in the pic.

[Mitch Wright]

Thanks John, that is the line of thinking I have as well.

John your Gen3 Coupe out of the box is impressive nice work.

[Hindsight]

Great info Mitch, thanks. So you are going with 400# rear springs then, or going from 300# to 350# and not 400# front?

I'm very interested in seeing your front sway bar setup!

Like, you I have the same zero understeer anywhere on the track and I too would like mine to push just a bit and back it up from there a tad. I was really hoping to do it with an adjustable bar because spring changes are more of a pain and cost money every time you want to make an adjustment.

I need aero and some slicks lol.

[Mitch Wright]

Right now we are getting ready to move so most all my tools and equipment are packed up, I hope to have my garage shop set up in the next few weeks or at least enough so I can get to my stuff. My bar sliders and mounting blocks are expected to arrive Friday
I will take some photos of the bar when I can get to it.
I am running BFG R1S slicks with aero, I currently have 350# front springs and 500# rear, that is were I will start once I get the bar installed. I have a set of 400# front springs I will try before I install the bar just to see what that change is. I have a set of 550# and 600# rear springs but not planning to try them until I start playing with the front bar.
Currently the car is living at the track so I can play with some stuff working out of my small tool box.

[Hindsight]

Mitch, can you talk a bit about the sway bar you are fabricating? IE how are you attaching the arms to the tube, etc?

I've done some research on building a bar of my own and it seems fairly straight forward: Use solid 4130 rod, use a torch to heat the area you want to bend, bend it, have the ends machined flat, then have it heat-treated. I'm leaning that direction. Need to find a shop that can do the machining and heat treating though.

It could be easier to do a tube-type setup (where I have a straight tube that I cut to length and weld arms onto) but I'm unsure of the calculations required to determine force, compared to the solid bar I have on there now. I'm sure there is some data out there somewhere... just need to search for it.

[Mitch Wright]

It is pretty straight forward here is the calculator that I have been using http://www.gtsparkplugs.com/Sway-Bar-Calculator.html
My mock up is made from .750 conduit to play with fit and Arm location. I have made bars using both spring steel and 4130 tubing, the bars I am making for my 818 are 4130 tubing stating with .095 wall, I have .120, .083 and .065. If you don't have a bender you can plug both ends pack the tube with sand heat and bend, that will prevent you from kinking the tube.
My plan right now is to fish mouth bar on either end and weld the arms to the bar. Before I do that I need to make sure I can get the bar out with out too much grief. If removal is a problem I will weld on a flange on one end and the arm and bolt the arm to the bar.
The 4130 bars I have made in the past for our Trans Am and World Challenge cars I never have heat treated, not saying it is the right way but the bars always did the job.
When I had the car out Sunday I was also looking at and toying with the idea of moving the arms inboard of the bar mounts which will (I think) provide a ton more room for the arms.
I am now excited to get back to building my front bar, which will be a few weeks once we get moved and I set up the garage.

[Hindsight]

Thanks for the input. Great idea on using conduit!

What's the point of using hollow instead of solid core bars? Lighter weight for the same effective leverage (assuming larger diameter on the tube version)?

[Mitch Wright]

Weight is the reason we have used hollow Bars. On the Trans Am and Late Models we used up to 2" OD tubing.

[Hindsight]

Great info thanks Mitch.

Another question: When welding the arms to the bar, is there anything special you do beyond welding around the perimeter? IE do you drill a hole and put a bolt or a roll pin or something else through there?

[Mitch Wright]

No just fish mouth the tube if using tube for the arm, that will give a strong joint. I do drill a small hole as vent in the bar if I am capping the ends. If I am using a blade for an arm I will drill a hole in the blade to slide the tube through to be able weld both sides.

[Hindsight]

I'm planning on using a solid bar so it sounds like what I had in mind will work - drilling a hole in the blade, sliding it on to the bar, then welding around both sides.

[DanielsDM]

Thanks for the input. Great idea on using conduit!

What's the point of using hollow instead of solid core bars? Lighter weight for the same effective leverage (assuming larger diameter on the tube version)?

With a solid bar the material in the middle isn't doing anything except adding weight. Play around with the calculator Mitch pointed to; Just for comparison enter the following:
A=10
B=31.94
C=10
OD=.75
ID = 0 (solid bar)
The stiffness calcs to 100lb/in

If you change ID = .25 (.250 wall tube, very thick), the stiffness drops to 98.8 (the middle .25 does essentially nothing)
Change ID = .375 (3/16 wall tube), the stiffness drops to 93.8 (the middle 3/8 isn't doing much either)
Change ID = .500 (1/8 wall tube), the stiffness drops to 80.3 and the weight is only 56% of a solid bar.

Another reason to use tube is you can build bars with the same OD but different wall thicknesses and they will be a direct swap, no need to change mounting bushings.

[Hindsight]

That makes sense Daniel - I hadn't thought about the fact that you could keep the same OD while increasing stiffness via wall thickness. Pretty cool idea. Only thing is I wonder how many wall thicknesses are available in a single OD? I'll have to do some searching on McMaster.

I will say that I'm having fun researching and learning about the finer aspects of track setup..... things like how to test for ideal static camber, camber gain, suspension frequency, etc. Fascinating stuff. I also think it would be a lot of fun to build a custom sway bar for the 818. If I find a bar size and setup that works well, I might offer it here to other forum members.

[Mitch Wright]

The last of my sway bar hardware arrived yesterday so no more excuses not to finish.
Sway bar hardware.jpg

[Hindsight]

I give up - what are those pieces for? Are the red pieces to make the swaybar adjustable without having to drill adjustment holes in the end of it?

[Mitch Wright]

Yes the red anodized parts are sliders/adjusters that slide up or down the arm to increase or decrease the bar stiffness. The green Delon bits are the sway bar mounts.

[Hindsight]

Very cool! Means that if you bend a bar instead of welding arms, you don't have to mill the ends of the bar flat and drill holes through. I'm sure it also makes using a hollow bar much easier. Looking forward to seeing the end result.

[fastzrex]

Another online source for 4130 tube I have used is onlinemetals.com

There are at least 10 different wall thicknesses available in .75" OD.

[fastzrex]

It is pretty straight forward here is the calculator that I have been using http://www.gtsparkplugs.com/Sway-Bar-Calculator.html
My mock up is made from .750 conduit to play with fit and Arm location. I have made bars using both spring steel and 4130 tubing, the bars I am making for my 818 are 4130 tubing stating with .095 wall, I have .120, .083 and .065. If you don't have a bender you can plug both ends pack the tube with sand heat and bend, that will prevent you from kinking the tube.
My plan right now is to fish mouth bar on either end and weld the arms to the bar. Before I do that I need to make sure I can get the bar out with out too much grief. If removal is a problem I will weld on a flange on one end and the arm and bolt the arm to the bar.
The 4130 bars I have made in the past for our Trans Am and World Challenge cars I never have heat treated, not saying it is the right way but the bars always did the job.
When I had the car out Sunday I was also looking at and toying with the idea of moving the arms inboard of the bar mounts which will (I think) provide a ton more room for the arms.
I am now excited to get back to building my front bar, which will be a few weeks once we get moved and I set up the garage.

Mitch, I see you do not heat treat the bars. Do the bars' torsion rating stay the same through a normal season? Or have you had a funky handling one day and replacing the bar fixes the issue?

[fastzrex]

The last of my sway bar hardware arrived yesterday so no more excuses not to finish.
Sway bar hardware.jpg

I would also like to see your assembly. Looking forward to pictures!