Track Monster Rev 2

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1 year 6 months ago #3020 by HeadBall
HeadBall created the topic: Track Monster Rev 2
I started working on the next revision of the track monster. The first step is improving the suspension geometry front and rear. The next goal is to make it possible to use generic coil overs so I don't have to pay the Corvette tax. The work is slow because I'm not a great CAD designer. Anyway, it's a start.

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1 year 6 months ago #3021 by darkshadowford
darkshadowford replied the topic: Track Monster Rev 2
Nice! For improving the chassis geometry, are you looking at using a software like Adams Chassis? Any other big changes you want to do for Rev 2 vs Rev 1?

The Ginger

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1 year 6 months ago #3023 by HeadBall
HeadBall replied the topic: Track Monster Rev 2
Right now, I am building a model in Solidworks so I can simulate all the movements and measure/interrogate the model. I also have sSNAP (very old version) for doing some analysis. Do you have Adams?

Here is the work for tonight. As they say, you eat an elephant one bite at a time.

Ken

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1 year 6 months ago #3026 by darkshadowford
darkshadowford replied the topic: Track Monster Rev 2
I do have Adams, not very good at it besides some rough A to B comparisons. The hardest part is setting up the initial model and all the hardpoint locations. If I could get my hands on an existing C5/C6 Adams model I could do some simple calculations. I'm not familiar with Solidworks chassis modeling, hopefully it'll help you get the job done. I'm interested in seeing where you take the Rev 2 design.

Are you planning on using the C5/C6 knuckles like your current car, or do the new arms use a different knuckle?

The Ginger

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1 year 6 months ago #3027 by HeadBall
HeadBall replied the topic: Track Monster Rev 2

darkshadowford wrote: I do have Adams, not very good at it besides some rough A to B comparisons. The hardest part is setting up the initial model and all the hardpoint locations. If I could get my hands on an existing C5/C6 Adams model I could do some simple calculations. I'm not familiar with Solidworks chassis modeling, hopefully it'll help you get the job done. I'm interested in seeing where you take the Rev 2 design.

Are you planning on using the C5/C6 knuckles like your current car, or do the new arms use a different knuckle?


What information do you need from the C5/C6? I still have the coordinates from the first time I went through this. I believe it was actually Matt who posted them. I also have the CAD models for the a-arms and uprights.

In Solidworks, I'm just modeling the parts and then creating an assembly. Assuming I define the joints correctly, I can then move the suspension through its travel and measure the change in camber, caster, roll center, etc. It's not the cleanest way to do it, but it serves two purposes. I will have a model of the suspension done and then I can integrate that with the new chassis. When I designed the first chassis I never modeled the suspension.

As for the spindle, I'm still deciding. I am debating using fabricated spindles from Coleman or Howe. Brandon's car has the Howe stuff and Kenny's Panoz uses the Coleman stuff. They have the added benefit of being inexpensive and they use easy to find ball joints and bearings. My other concern is using parts other guys have so we can share spares when something breaks at the track. The Corvette stuff is nice, but the hubs are expensive and the options for brakes are limited (meaning really expensive to get big brakes). Hopefully, the geometry will help make the decision.

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1 year 6 months ago #3028 by darkshadowford
darkshadowford replied the topic: Track Monster Rev 2
Well I still have the old C5 data that Matt sent me too, that actually should be the majority of the hard points needed. Looks like the front has a spindle alignment, but I don't see it on the rear. Also need front and rear wheel center locations to really set alignments. Some assumptions needed on bushings rates vs spherical joints. Same with jounce/rebound bumpers. There is a rear stabar attachment, but still need stabar geometry (attachment to subframe locations), and all the front stabar geometry, which wouldn't be too tough taking a rough measurement off existing parts. Could use rough idea of spring rates. It'll be difficult, but doesn't look impossible. Should be able to kick out rough some camber gains, toe-curves, etc.

Separate from Adams, depending on what you are trying to do and what you are predicting for vehicle sprung/unsprung weights and motion ratios on springs/bars, we could do some rough calculations for things like frt/rear ride frequencies, roll gradients, and some other cool attributes to predict understeer/oversteer, but it could help narrow down on spring rates, and with a little more effort, stabar rates.

The Ginger

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1 year 6 months ago #3029 by HeadBall
HeadBall replied the topic: Track Monster Rev 2

darkshadowford wrote: Well I still have the old C5 data that Matt sent me too, that actually should be the majority of the hard points needed. Looks like the front has a spindle alignment, but I don't see it on the rear. Also need front and rear wheel center locations to really set alignments. Some assumptions needed on bushings rates vs spherical joints. Same with jounce/rebound bumpers. There is a rear stabar attachment, but still need stabar geometry (attachment to subframe locations), and all the front stabar geometry, which wouldn't be too tough taking a rough measurement off existing parts. Could use rough idea of spring rates. It'll be difficult, but doesn't look impossible. Should be able to kick out rough some camber gains, toe-curves, etc.

Separate from Adams, depending on what you are trying to do and what you are predicting for vehicle sprung/unsprung weights and motion ratios on springs/bars, we could do some rough calculations for things like frt/rear ride frequencies, roll gradients, and some other cool attributes to predict understeer/oversteer, but it could help narrow down on spring rates, and with a little more effort, stabar rates.


Ryan
I can help you get some of the physical measurements. My current car has a rear cradle from a C5, so it has the sway bar mounting points. I also have several front sway bars, so we can get the measurements we need from those. The sSNAP program I have provides all the curves. The only issue is the program is old and runs on a Windows 95 laptop I have. The laptop crashes a lot.

I've written an Excel program that does a pretty good job of calculating camber, but I don't have the bumpsteer completely ironed out. I may download the Performance Trends demo again if needed as well. My last option is I also have CarSIM for full vehicle simulation.

My main concern with the current car is that it really doesn't live up to it's potential. The car is 1000 pounds ligher, and a couple inches lower, than a C5 Corvette but it doesn't really corner any harder. My car shines on corner exit, but everywhere else a well sorted Corvette is just as good or better.

Besides the obvious loose nut behind the wheel, the car really should do better. My goal is to make that easier by doing a few things.

1. Reduce friction in the system by replacing bushings with rod ends
2. Increase the range of adjustment (specifically camber in the rear)
3. Reduce the amount of anti in the system (anti-dive and anti-squat)
4. Confirm the roll angle aligns with the camber gain
5. Reduce the amount of corner entry and mid corner oversteer

We'll see how it goes.

Ken

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1 year 6 months ago #3033 by HeadBall
HeadBall replied the topic: Track Monster Rev 2
Not a lot of progress tonight. I did find a potential spindle supplier. Coleman Racing makes custom spindles based on their existing components.

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1 year 6 months ago #3036 by jaymsu
jaymsu replied the topic: Track Monster Rev 2
Engineers....... :pinch:


I'm sure you guys are talking in English but I don't get half of it..... I gotta go back to language school. :huh:

2006 Corvette w/ Z51 package: TOY4JAY III
2007 Corvette Z06 (550whp monster): TOY4JAY II
2002 'almost' stock Corvette coupe: TOY4JAY I

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1 year 6 months ago #3038 by darkshadowford
darkshadowford replied the topic: Track Monster Rev 2

HeadBall wrote:

darkshadowford wrote: 1. Reduce friction in the system by replacing bushings with rod ends
2. Increase the range of adjustment (specifically camber in the rear)
3. Reduce the amount of anti in the system (anti-dive and anti-squat)
4. Confirm the roll angle aligns with the camber gain
5. Reduce the amount of corner entry and mid corner oversteer


When you say reduce anti, you want the car to dive more and squat more? Just my $0.02, one idea I'd have is lower the spring rates. This might also help with the mid-corner oversteer. A car that rolls more is easier to drive since it'll give your brain a visual representation of where the car is compared to it's limit, rather than the brain trying to detect yaw. But it would be good to make sure the camber gains align with a higher roll gradient. Another idea, depending on your geometry, if your roll centers are around the same as a C5 but your CG height is much lower than the C5, that could cause some problems with instantaneous weight transfer, do you ever pull a front or rear tire off the ground?

I know you mentioned getting dampers that were easy to rebuild. Have you played with the damper tuning for corner entry?

Also, are you thinking of going to a larger staggered tire set-up? For a car with a high rear weight bias, more rear tire would help even out the car (or less front), if not, a big rear wing would help too. Have you tried capturing tire temps? Also, one big difference from a C5 is the aero, are you designing rev2 with a little more aero?


The Ginger

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1 year 6 months ago #3040 by HeadBall
HeadBall replied the topic: Track Monster Rev 2
Lots of questions, so I'll try to break them out.

1. I want less anti dive and anti squat because I believe the suspension is getting into a bind situation. I say this because of the trouble I have with the front tires locking up under braking and also because of the way the car will suddenly break loose under power sometimes. The anti geometry was designed for a car with a wheelbase about a foot shorted and a CG higher. From the reading I've done on the subject, there is little to no need for anti on a race car. Production cars use it to reduce the feeling of the car pitching for passenger comfort.

2. I've only seen the car pull a front wheel off the ground at Mid-Ohio in the esses. I don't consider that to be much of a problem.

3. I've never played with the dampers. They have never come off the car since I built it. I have no idea if they even work. They were used when I bought them over 10 years ago. This is one of the reasons I want to design a system that will work with more generic shocks, so I don't have to pay for Corvette specific items.

4. I've tried lots of tire combinations throughout the year. This year, I'm going to a 255/17 tire in front. However, I'm doing this with the goal of increasing front grip by getting to operating temps faster and also to reduce the amount of feedback I'm getting in the steering. We have a tire pyrometer but we have done a poor job of collecting data. I'm blaming the intern.

5. I may do some aero, but that is secondary to getting the suspension improved. A C5 without a wing and splitter isn't making much down force, but it does have a higher top speed.

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1 year 6 months ago #3045 by Grog
Grog replied the topic: Track Monster Rev 2
So I hate to ask, but...

1) Have you conclusively determined that geometry in the current track monster is wrong?

2) if so, that it cannot be reasonably reconfigured?

3) if not, could it be worth paying an suspension expert to see if it just needs a better setup (Toe, camber, cast, spring rates, damping, tire sizes, tire pressures)?

4) Or is Rev 2 as much for fun as it is an improvement?

92 Miata (~92 whp)
Slow is smooth. Smooth is fast.

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1 year 6 months ago - 1 year 6 months ago #3046 by HeadBall
HeadBall replied the topic: Track Monster Rev 2

Grog wrote: So I hate to ask, but...

1) Have you conclusively determined that geometry in the current track monster is wrong?

2) if so, that it cannot be reasonably reconfigured?

3) if not, could it be worth paying an suspension expert to see if it just needs a better setup (Toe, camber, cast, spring rates, damping, tire sizes, tire pressures)?

4) Or is Rev 2 as much for fun as it is an improvement?


1. The geometry isn't "wrong". It needs to be improved. I know that the camber gain doesn't match the roll angles I see, and I know it has too much anti dive. I also know that it has urethane bushings.

2. Any one of the items above can be solved with some cutting and welding. However, when you combine a few of them, AND the fact that I want a safer cockpit, it's easier to build a new chassis.

3/4. I'm not paying anyone. This is part of the fun for me and as an engineer, I would rather learn myself.

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Last Edit: 1 year 6 months ago by HeadBall.

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1 year 6 months ago #3048 by darkshadowford
darkshadowford replied the topic: Track Monster Rev 2

HeadBall wrote: Lots of questions, so I'll try to break them out.

1. I want less anti dive and anti squat because I believe the suspension is getting into a bind situation. I say this because of the trouble I have with the front tires locking up under braking and also because of the way the car will suddenly break loose under power sometimes. The anti geometry was designed for a car with a wheelbase about a foot shorted and a CG higher. From the reading I've done on the subject, there is little to no need for anti on a race car. Production cars use it to reduce the feeling of the car pitching for passenger comfort.

2. I've only seen the car pull a front wheel off the ground at Mid-Ohio in the esses. I don't consider that to be much of a problem.

3. I've never played with the dampers. They have never come off the car since I built it. I have no idea if they even work. They were used when I bought them over 10 years ago. This is one of the reasons I want to design a system that will work with more generic shocks, so I don't have to pay for Corvette specific items.

4. I've tried lots of tire combinations throughout the year. This year, I'm going to a 255/17 tire in front. However, I'm doing this with the goal of increasing front grip by getting to operating temps faster and also to reduce the amount of feedback I'm getting in the steering. We have a tire pyrometer but we have done a poor job of collecting data. I'm blaming the intern.

5. I may do some aero, but that is secondary to getting the suspension improved. A C5 without a wing and splitter isn't making much down force, but it does have a higher top speed.


I'd agree with all that, especially number 1 & 4. Dang intern, maybe I can help you get some tire temps this year. Are you considering putting the rear wing back on? If you know your current spring rates, I could do some rough calculations on roll grandients.

The Ginger

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1 year 6 months ago #3049 by Grog
Grog replied the topic: Track Monster Rev 2

HeadBall wrote:
1. The geometry isn't "wrong". It needs to be improved. I know that the camber gain doesn't match the roll angles I see, and I know it has too much anti dive. I also know that it has urethane bushings.

2. Any one of the items above can be solved with some cutting and welding. However, when you combine a few of them, AND the fact that I want a safer cockpit, it's easier to build a new chassis.

3/4. I'm not paying anyone. This is part of the fun for me and as an engineer, I would rather learn myself.



1./2. I get that. Redo the front and rear, then redoing the middle doesn't make sense.

3./4. As an engineer as well, I totally understand. I would consider it tuition if they let you watch and learn along the way...but I agree more fun to do it yourself.

It will be fun to see the progress. (And the final product, of course)


Carry on.

92 Miata (~92 whp)
Slow is smooth. Smooth is fast.

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1 year 6 months ago #3050 by Grog
Grog replied the topic: Track Monster Rev 2

HeadBall wrote:
1. The geometry isn't "wrong". It needs to be improved. I know that the camber gain doesn't match the roll angles I see, and I know it has too much anti dive. I also know that it has urethane bushings.

2. Any one of the items above can be solved with some cutting and welding. However, when you combine a few of them, AND the fact that I want a safer cockpit, it's easier to build a new chassis.

3/4. I'm not paying anyone. This is part of the fun for me and as an engineer, I would rather learn myself.



1./2. I get that. Redoing the front and rear, then redoing the middle doesn't make sense.

3./4. As an engineer as well, I totally understand. I would consider it tuition if they let you watch and learn along the way...but I agree more fun to do it yourself.

It will be fun to see the progress. (And the final product, of course)


Carry on.

92 Miata (~92 whp)
Slow is smooth. Smooth is fast.

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1 year 5 months ago #3060 by HeadBall
HeadBall replied the topic: Track Monster Rev 2
I finally went back to my original suspension layout and checked what kind of anti-dive I have in the current Track Monster. I downloaded the demo of Performance Trends Suspension Analyzer and loaded the 2001 Corvette file they have. Below is what I found:

Setup Anti-dive
Stock C5 anti-dive at curb height 54%
Increase wheelbase to Track Monster 61%
Reduce CG height 2 inches 68%
Dive 0.5" 70%
Dive 1.0" 72%

The Track Monster wheelbase is about 14" longer than the C5, so that bumps the static anti-dive up by 7%. Based on my best guess, the CG is about 2" lower, so another increase of 7%. When I installed the suspension, I set it up so the suspension was lowered a bit (basically already into bump compared to a stock Corvette). I don't remember the exact amount, but it looks like I'm adding another couple percent. So, the data does show the changes I made to the original Corvette geometry have increased the anti-dive by a good bit. Turns out, I'm not completely crazy. :silly:

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