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Kenny Brown AGS 4.5: Have I Been Living Under A rock Or Is This Brand New?

Dave_W

Cones - not just for ice cream
448
449
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Autocross
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Connecticut
Found this video where Kenny Brown is explaining his theory on where he wants the front & rear roll centers on an S197. The "we have something coming... that will blow your mind" comment may be about the Mumford link setup.
 

carver

breaker of wrenches
372
470
ontario
I,m curious watching the vid in the first post. After the 2:30 mark it looks like a lot of side to side movement in the rear axle. It actually looks unstable to me. It also looks like the axle is pushing against the left side exhaust pipe. Is that how they work? I'm thinking my pan hard bar has way less side to side movement. IMHO. I am not an expert in suspension it's just something I noticed....
 
4,599
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W2W Racing
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Pleasanton: 1/2 way between Sonoma and Laguna Seca
The YouTube video is dated March 2021 so I guess that's when he decided to go public with it.
I believe that video is unlisted, only those in possession of the link can view it. We weren't supposed to share it.
Kenny has done a few limited reveals to small groups starting with his speed therapy academy alumni who were able to buy the first 10 production units, then another limited reveal and 10 units went to the speed therapy group with the big public reveal yet to come.
 

Dave_W

Cones - not just for ice cream
448
449
Exp. Type
Autocross
Exp. Level
20+ Years
Connecticut
After the 2:30 mark it looks like a lot of side to side movement in the rear axle. It actually looks unstable to me.
I believe what you're seeing is body roll with the (much) lower roll center of the Mumford link.

With the Panhard & Watts, the RC is about axle height, so when the body rolls around that point, a camera mounted to the body and looking at the diff doesn't see much, if any, lateral movement of the axle, only rotation. But with the RC at ground level, when the body pivots around the RC a camera on the body looking at the diff "sees" the axle moving laterally with the body roll, but it's really the body moving on a different virtual pivot point. It's a frame-of-reference thing.

It does point out that you need to consider the change in body roll-induced lateral movement in relation to the wheels if you're running wide rear wheels/tires and are tight on wheelwell clearance. You might get sidewall rubbing with the Mumford when you didn't with a Panhard or Watts.
 

carver

breaker of wrenches
372
470
ontario
I believe what you're seeing is body roll with the (much) lower roll center of the Mumford link.

With the Panhard & Watts, the RC is about axle height, so when the body rolls around that point, a camera mounted to the body and looking at the diff doesn't see much, if any, lateral movement of the axle, only rotation. But with the RC at ground level, when the body pivots around the RC a camera on the body looking at the diff "sees" the axle moving laterally with the body roll, but it's really the body moving on a different virtual pivot point. It's a frame-of-reference thing.

It does point out that you need to consider the change in body roll-induced lateral movement in relation to the wheels if you're running wide rear wheels/tires and are tight on wheelwell clearance. You might get sidewall rubbing with the Mumford when you didn't with a Panhard or Watts.
I think I get what your saying but the Cortex video ( post# 20) looks rock solid in regards to lateral movement compared to the Mumford Link video but maybe it's just the camera angle and the way I'm interpreting it. :)
 
I think I get what your saying but the Cortex video ( post# 20) looks rock solid in regards to lateral movement compared to the Mumford Link video but maybe it's just the camera angle and the way I'm interpreting it. :)
I think its still what the other DaveW said, the RC is still setup close to axle height on that Cortex video and certainly not on the KB one.

My old tubeframe race car "Mustang" had a front RC at 3.5 and a rear adjustable from 4-8" and typically ran around 6. I could also put the instant center wherever I wanted it and everything had very long links and very little migration of those numbers. And a very low CG and polar moment (crank center about 8" off ground, engine set back 18" from axle center line)

My S197 has none of that. It seems like all the off the shelf panhard/watts for them have the rear RC way too high, but at least the Cortex offers a bit more adjustment (I purchased one, it is on backorder since June) but all that said, I can't figure how a super low rear RC would work without crazy spring rates and blowing forward bite. It seems to get back into all the shiznit I fought back in the Fox Mcstrut days where your front RC is subterranean and moving all over the place and no matter where the rear was, the slope was gigantic and it was wonky at best.

All that said, KB is not a joke and knows more than me, so I am certainly watching all this. A mumford was on my to-do list of the old tube frame car, I just never got around to it before tiring of the car. It offers a lot of advantages and IIRC the RC is crazy stable.

DaveW
 
Kenny actually didn't invent it, the basic concept was in an ancient engineering book he came across decades ago and liked the idea and developed it for the s197.
It’s called a Mumford link.

 

Dark Horse

2012 BOSS 302 LS 541
I installed the K-link this summer. My first impression while the car was on jack stands was that rear axle had a crazy level of articulation compared to the panhard bar. The car does handle differently so there is some learning curve on the new handling characteristics. The car feels much more planted at corner entry all the way through corner exit. At HMP, my home track, I bested my quickest lap time by 4 seconds between two back to back sessions. This was especially impressive considering i was running smaller diameter tires than normal (30/650 vs 30/680) and not having 5th gear due to no synchronizers! I am looking forward to seeing what the car is capable of next year with the larger diameter tires and a healthy transmission.
 

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