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PostPosted: Tue Dec 05, 2017 7:57 pm 
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alwaysinboost wrote:
great job with the new rule set.

Greg G. wrote:
you haven't driven a car that has power that is absolutely unusable because of inherently flawed suspension design, as you watch Miatas and S2000's at full throttle sticking around corners.


so much of this.


^ says the guy with an e36 with stock suspension arms and no metal bushing with all the TTD track records in two regions. i bet you two beers that you're building an e36 sedan to get .7 for arms and .2 for 4 door right off the bat ;)

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PostPosted: Wed Dec 06, 2017 4:40 am 
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Quote:
We are going to start conservative, as we can always decrease the assessment in the future if we find it appropriate.


The only feedback I've been hearing, from anyone, is that 0.7 is far too aggressive. I thought we wanted the rules to start "conservative"?

Quote:
...you haven't driven a car that has power that is absolutely unusable because of inherently flawed suspension design, as you watch Miatas and S2000's at full throttle sticking around corners.


I had an E36M3 track car. it was a beast and put power down excellent at corner exit. I've also rode in an E36M3 with stock rear control arms at an autocross, which is tighter and even harder to put power down that road racing, and the car was unbelievably stuck - he was flooring it through tight turns.

Also, one reason a miata or FRS or RX8 or S2000 with 140-150 torque can go "flat-out" through corners is because they have so much less power and torque at that RPM! Of course a torquey car like a BMW or 370Z or Mustang will need to feather the throttle.

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PostPosted: Wed Dec 06, 2017 5:06 am 
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cadmad wrote:
One region states how the M3 sets track records, and another region has S2000's destroying everyone, and yet another has Miatas and FR-S's leading every event. NASA has been fairly vigilant over the years to try to ensure that no single model becomes the only possible winning model in ST/PT/TT classes. I don't expect that to just stop.


ALL of those cars have superior suspensions.
incorporating points for upper "A" arm suspensions opens the door for everyone else.
NASA has found the great divide!
great job![/quote]

Actually, the NASA rules are claiming that the BMW M3 does not have a superior suspension design, despite an extensive win and track record history.

I don't mind being very specific here. I believe the intent of the A-arm rule is to allow cars such as the MINI or Nissan Sentra or Neon or RWD cars with front struts and solid rear axle to have a fair and honest adjustment to offset real-world cornering disadvantages. However, I (and multiple others who have owned and raced BMWs and are not afraid to speak up) believe this modifier specifically against A-arms intentionally penalizes those cars while not penalizing BMWs, which are at no real-world performance disadvantage. If anything, the large torque advantage of a BMW (something that is measureable and not speculated) should offset any possible cornering advantage of a A-arm car. We also forget that A-arm cars lose contact patch and therefore braking traction more than strut cars, a disadvantage of A-arm cars that is glossed over.

Should we have a modifier to help the TRULY disadvantaged cars stated above? YES.

So how should we re-word the modifier? "+0.7 for cars with upper A-arms or multilink suspension designs."

Or, if people don't want to be penalized (like A-arm cars currently are!), we give a credit to: "Cars with struts at all four corners, or cars without a multilink or upper A-arm design".

As it's written, it's a ticket for a spec-BMW class.

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PostPosted: Wed Dec 06, 2017 5:08 am 
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f1honda wrote:
alwaysinboost wrote:
great job with the new rule set.

Greg G. wrote:
you haven't driven a car that has power that is absolutely unusable because of inherently flawed suspension design, as you watch Miatas and S2000's at full throttle sticking around corners.


so much of this.


^ says the guy with an e36 with stock suspension arms and no metal bushing with all the TTD track records in two regions. i bet you two beers that you're building an e36 sedan to get .7 for arms and .2 for 4 door right off the bat ;)


so much of this.

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PostPosted: Wed Dec 06, 2017 6:27 am 
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hufflepuff wrote:
cadmad wrote:
One region states how the M3 sets track records, and another region has S2000's destroying everyone, and yet another has Miatas and FR-S's leading every event. NASA has been fairly vigilant over the years to try to ensure that no single model becomes the only possible winning model in ST/PT/TT classes. I don't expect that to just stop.


ALL of those cars have superior suspensions.
incorporating points for upper "A" arm suspensions opens the door for everyone else.
NASA has found the great divide!
great job!


Actually, the NASA rules are claiming that the BMW M3 does not have a superior suspension design, despite an extensive win and track record history.

I don't mind being very specific here. I believe the intent of the A-arm rule is to allow cars such as the MINI or Nissan Sentra or Neon or RWD cars with front struts and solid rear axle to have a fair and honest adjustment to offset real-world cornering disadvantages. However, I (and multiple others who have owned and raced BMWs and are not afraid to speak up) believe this modifier specifically against A-arms intentionally penalizes those cars while not penalizing BMWs, which are at no real-world performance disadvantage. If anything, the large torque advantage of a BMW (something that is measureable and not speculated) should offset any possible cornering advantage of a A-arm car. We also forget that A-arm cars lose contact patch and therefore braking traction more than strut cars, a disadvantage of A-arm cars that is glossed over.

Should we have a modifier to help the TRULY disadvantaged cars stated above? YES.

So how should we re-word the modifier? "+0.7 for cars with upper A-arms or multilink suspension designs."

Or, if people don't want to be penalized (like A-arm cars currently are!), we give a credit to: "Cars with struts at all four corners, or cars without a multilink or upper A-arm design".

As it's written, it's a ticket for a spec-BMW class.[/quote]

Agreed 100%. I'm not sure why it is being ignored that M3s without metal bushings or any fancy suspension arms are already extremely competitive cars.


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PostPosted: Wed Dec 06, 2017 10:36 am 
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Hey! Looking to get some clarification and understanding on a couple of the rules...

5) Non-OEM metallic and/or spherical design replacement suspension bushing
modifications on control/camber/toe arms/links, panhard rods, watts links, and
torque arms shall be assessed a Modification Factor which is in addition to and
additive to #3 & #4 above.

6) Non-OEM shocks/struts with an external reservoir (or piggyback) OR
with shaft diameter 40mm or greater shall be assessed a Modification Factor.

I have a BRZ and have a basic coilover setup (Fortune Auto 500's), do either of these two rules fit doing a coilover setup like that? I guess I just don't really know the exact bushings they are talking about and then I also don't know if I know if the shocks are 40mm or not. I think I assume that I do not have to take these hits but thought I would ask for some help understanding.

If I don't have to take these (knowing I also have to take the double wishbone and I have control arms), I think the rules are fair to me. I should be able to compete pretty well with my current setup (which last year was just into TTC).

Thanks for the help!


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PostPosted: Wed Dec 06, 2017 12:31 pm 
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hufflepuff wrote:

The only feedback I've been hearing, from anyone, is that 0.7 is far too aggressive. I thought we wanted the rules to start "conservative"?


Conservative is to start out with more ballast or less power for these vehicles, and allow lighter weight or more power in the future if needed. Despite your local BMW success, which could certainly be track dependent, or driver dependent, or $$$ dependent, our National data don't seem to show the same findings.
We are aware of the BMW not having upper A-arms, and we also have a lot of data from the past, showing that vehicles like the Miata in PTD/TTD were faster than well prepped PTC/TTC BMW's with good drivers (same goes for FR-S/BRZ, and S2000's tended to dominate the C class). Most of these cars were actually Dyno re-classed, and we know where their Wt/HP ratios were at and how much room they had for additional Mods. The A-arm Mod Factor brings these vehicles very close to where they were at using Dyno re-classing (maybe 0.1-0.2 off). Is it possible that we will need to do something about the BMW's? Maybe or maybe not, but despite some folks opinions that rules should be in stone forever, we don't have a problem making small adjustments to try and keep the competition at the driver level if possible. We have seen what can happen with factory supported Miatas and FR-S's, and on more than one occasion it has gone like this: BMW sets new TT track record, and then Miata or FR-S or Boxster goes out in a later session and beats the new record by 4 seconds. So, we are not going to make changes to this Mod Factor at this time, so you can stop repeatedly arguing about it. We get your opinion, and you may end up being correct, but we are going to let the cars do the talking, not the bench. Yes, it was debated if the number was too high, and NASA executives decided to keep it there to start. If it did turn out to be a "BMW spec class", that wouldn't last too long.

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PostPosted: Wed Dec 06, 2017 12:39 pm 
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badamowski wrote:
Hey! Looking to get some clarification and understanding on a couple of the rules...

5) Non-OEM metallic and/or spherical design replacement suspension bushing
modifications on control/camber/toe arms/links, panhard rods, watts links, and
torque arms shall be assessed a Modification Factor which is in addition to and
additive to #3 & #4 above.

6) Non-OEM shocks/struts with an external reservoir (or piggyback) OR
with shaft diameter 40mm or greater shall be assessed a Modification Factor.

I have a BRZ and have a basic coilover setup (Fortune Auto 500's), do either of these two rules fit doing a coilover setup like that? I guess I just don't really know the exact bushings they are talking about and then I also don't know if I know if the shocks are 40mm or not. I think I assume that I do not have to take these hits but thought I would ask for some help understanding.

If I don't have to take these (knowing I also have to take the double wishbone and I have control arms), I think the rules are fair to me. I should be able to compete pretty well with my current setup (which last year was just into TTC).



Thanks for the help!

You do not need to take #5, as it does not apply to camber plates (not listed).
I don't think you need to take #6 based on the photos, but I can't find Specs on the Fortune Auto website. So, you should contact Fortune Auto, and ask how big the shaft diameter is on your shocks.

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PostPosted: Wed Dec 06, 2017 12:42 pm 
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914porsche209 wrote:
Hey Greg,
Thanks for getting these rules out. I hope ST5 has a good turn out!
Can I get a clarification on 6.1.8. (5) Theres no mention about torsion bars here. My adjustable camber plates are mono-ball too.
Also, can I remove my torsion bars and switch to coil-overs?
Thanks,
Shane
Porsche 914
PS. That mid engine -.4 hurts!

Yes, you can convert to coil-overs.
Camber plates are not listed as requiring the Mod Factor for sphericals.

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PostPosted: Wed Dec 06, 2017 2:23 pm 
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Where do the tire recommendations stand? Classing the 100TW budget r comps with Hoosier R7s is off.

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