Thinking about ditching BMR springs

[BMR Tech]

To add, for those who do not like rake:

Chris Ho, who is a non-BMR employee with a non-BMR sponsored nor owned S550 uses our components to win on a regular basis.

He does run the SP763 Kit, though, not the SP080 Kit. So this would be a 7/8" front and 1/2" rear drop compared to stock height.

2017 class champion, and has already started out 2018 with a flawless record, multiple top lap awards and track record times.

I have race winning customers with both our performance AND our handling springs ;)

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[wildcatgoal]

Show me the scales and documentation on that one. Sounds like propaganda to me.

Ug... you are an engineer - there has to be a way to calculate it.

If the guy at my garage lets me use his corner scale again, and I can line up the right cars to do it, I'll do some corner weight testing. That'll be fun. I'm estimating after seeing how easily weight transfers watching vehicles get corner balanced and they experiment with rake for aero within class limitations. I will ask if I can use that 4-point scale in the near future.

I'm sure BMR has their corner weights from testing to prove me wrong, anyway. The rates on the BMR Handling springs make sense to me.

Regarding the part I linked to, I misread your sentence structure... that's my bad.

 

[BmacIL]

Ug... you are an engineer - there has to be a way to calculate it.

If the guy at my garage lets me use his corner scale again, and I can line up the right cars to do it, I'll do some corner weight testing. That'll be fun. I'm estimating after seeing how easily weight transfers watching vehicles get corner balanced and they experiment with rake for aero within class limitations. I will ask if I can use that 4-point scale in the near future.

I'm sure BMR has their corner weights from testing to prove me wrong, anyway. The rates on the BMR Handling springs make sense to me.

Regarding the part I linked to, I misread your sentence structure... that's my bad.

Yes, I did a calculation. 100 is definitely high. I'd believe it at 60-70. Static weight isn't everything, however, despite having some negative effects.

 

[wildcatgoal]

Well... it’s 100 with my fat ass in the car. :(

 

[BmacIL]

Well... it’s 100 with my fat ass in the car. :(

I was assuming a 4000 lb car (so with driver).

 

[wildcatgoal]

To add, for those who do not like rake:

Chris Ho

2017 class champion, and has already started out 2018 with a flawless record, multiple top lap awards and track record times.

Good for him! What’s the competition in Manila?

Seems his first event in 2017 was uncontested in class. Did well most the rest of the year against 3-4 other common cars. Interesting competition format - kind of a “chase me” sort of thing. I’d like to try that format, actually. Good luck, Chris... but I gotta ask... how about the sweet Steeda branding stripe on the side of his car though, eh? That has to count for something!!!

 

[DickR]

Yes, I did a calculation. 100 is definitely high. I'd believe it at 60-70. Static weight isn't everything, however, despite having some negative effects.

My understanding based on decades of paying attention to this topic is that ride height changes do not change front/rear static weight distribution other than very very very small amounts due to very very very small changes in the front/rear center of gravity location.

I'm sure someone here can do the trig IF they have accurate and precise CG location data but even though I'm an engineer my trig skills are too rusty and my motivation is less than zero.

Any change in static weight would be from different component weights such as lighter springs, etc.

There are a huge number of factors which are impacted by changing springs, bars, bump rubber length and rates, dampers, and so on that result in handling and ride changes. Static front/rear weight distribution from lowering isn't one of them.

Note that intentional corner balancing by changing ride heights at one corner simply changes the side to side weight distribution at both ends of the vehicle. That is raising the right front makes it heavier compared to the now lighter left front and also makes the left rear heavier than the now lighter left rear. Total front weight and total rear weights do not change.

 

[BmacIL]

My understanding based on decades of paying attention to this topic is that ride height changes do not change front/rear static weight distribution other than very very very small amounts due to very very very small changes in the front/rear center of gravity location.

I'm sure someone here can do the trig IF they have accurate and precise CG location data but even though I'm an engineer my trig skills are too rusty and my motivation is less than zero.

Any change in static weight would be from different component weights such as lighter springs, etc.

There are a huge number of factors which are impacted by changing springs, bars, bump rubber length and rates, dampers, and so on that result in handling and ride changes. Static front/rear weight distribution from lowering isn't one of them.

Note that intentional corner balancing by changing ride heights at one corner simply changes the side to side weight distribution at both ends of the vehicle. That is raising the right front makes it heavier compared to the now lighter left front and also makes the left rear heavier than the now lighter left rear. Total front weight and total rear weights do not change.

I'm giving the dog a bone by saying, ok I'll play, let's look at it like longitudinal weight transfer, but by less than a tenth of the amount of brake dive you'd see under hard track braking. It's not really a fair comparison though.

Since you're not changing the longitudinal position of the center of mass but by only the tiniest of margins, it will have almost no effect.

 

[Bigred911s]

I have the Ford Street Perf suspension and love it. Gives 1" drop all corners.

 

[wildcatgoal]

Interesting! Well, as I always say -- I'm happy to be wrong. If I'm creating misinformation, I'm sorry. Damn do I need access to a 4 point scale again. Now I wanna experiment.

I wish I could swap the BMR Handling springs in my car and go to AMP in close succession to a prior track day there - compare times. Too cash flow poor to be paying for that kinda fun times.

 

[cjldad]

I don't think you will go wrong with either of your ideas, nor others mentioned in this post, though my preference naturally leans with what I use and drive every day:

Ultralite Linears
Fixed Pro-Actions
1/4" Spacer Rear

This setup is refined, sporty, and has a hunger for performance. You won't be disappointed.

Doesn't this setup pretty much equal the BMR SP080 stance??

 

[Roadway 5.0]

You engineer types always make me smile. Use math to design the baseline, refine with a driver relaying feedback, feel, and performance. The best chefs season by taste.

 

[BmacIL]

You engineer types always make me smile. Use math to design the baseline, refine with a driver relaying feedback, feel, and performance. The best chefs season by taste.

You just perfectly described how engineers do their jobs.

 

[wildcatgoal]

You just perfectly described how engineers do their jobs.

Thankfully not surgeons. I'd rather not be peppered to taste... :shrug:

 

[BmacIL]

Thankfully not surgeons. I'd rather not be peppered to taste... :shrug:

:lol::lol:

Thankfully most practiced medicine isn't iterative.

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