Opinions on this suspension setup ?

[Rodeoflyer]

As for the weight. I would strongly suggest you take a really hard look at those K's... they are only about light, not about strong. I would avoid them like the plague. Saving weight is great when you don't shoot yourself in the foot in the process. Not only is the K subject to the torque of the engine, but the lateral load from cornering. You will have more weight, more power, and want to turn some corners, all of which will make life harder on a K-member and you are looking at a much more flimsy part.

I hate to hijack a thread that has already been hijacked once, but um - can you explain this a little more Sam? Not to sound like an ass, but this statement is misleading.

I'd hate to think pieces designed by the engineers at Griggs and Maximum are "flimsy". The only road racers running stock k-members are the guys in A-Sedan with it's ridiculously antiquated (Read: SCCA)and narrow-minded (Read: SCCA) ruleset.

*Quick Sidebar - for anybody that doesn't know about A-Sedan, they are stuck with 16" wheels and carburetors, stock k-members, and various other stupidities. They are basicly NASA CMC cars with 15k engines. You can't even run a new Camaro without putting 12" brakes on it and dropping a carbureted 305 in it. Then, if you win you get your car back in boxes after everybody cries and SCCA tears it apart.

I have Griggs on my race car, and the k-member on my street car was built by the guy that builds the World Challenge mustangs of Brandon/Mike Davis and Boris Said. Given their reputations and records, I just feel this statement sounds misinformed (which I don't believe Sam to be) or misleading (albeit hopefully unintentionally). I think the quoted statement could potentially do a disservice to shops that clearly know what the fuck they are doing.

Again - not in any way trying to be an ass (except the hating on SCCA - fuck them) , I just think this is a bad statement that could cost people customers unfairly. From what I have read, a poster has already been talked out of a BMR k-member. I'm not a fan of their control arms, but their k-member has been used successfully(although it isn't quite as light as they claim) in American Iron.

 

[SoundGuyDave]

Not sure about this year @ Road America, but @ the previous Runoff's @ HPT most every Hoosier runner was on A6's...

Just a softer compound, like most any road racing series that's not spec tired has. Michelin offers multiples for SportsCars, IndyCar has different compounds, F1, etc. Sure sometimes the compounds might be too soft, or the harder one too hard. But unlike adjustable dampers you can't change that.

Still working on the spring rates Dave and final pricing. Will have the bars out by Monday or Tuesday (need to finish some links for you).

Thanks, Sam, and +1 on the compound data. The autocross compounds work wonders for TT or TA type competition, but they just don't seem to hold up long enough for sprint race formats...

 

[Sam Strano]

To each his own..... The last place I think "light" is good is on control arms or what they attach to. I've heard the same claims from f-body guys "no problem" only to see the k's fail.

Like anything not all versions of something are the alike. Doesn't mean I hate all K-members, but I can tell you the one I was involved with for the f-bodies is a lot different than any other that existed. The K's for SN95 that MM makes, I'd happy sell to someone for track use. Don't sell Griggs, and frankly even finding a decent picture of their stuff is about impossible. Can't speak to it, would guess given their reputation it's fine.

We need not get into the rules thing. NASA has what I think are some stupid rules too, even as low as CMC and don't get me started about their "points" for TT classes. Some of the things you get dinged the same amount of points for in comparison to others is insane. Rules exist in any series, nobody likes all of them.

Further, we all have our opinions and as long as those opinions have some basis in fact beyond "because I think so" then I don't think I'm doing a dis-service to anyone, by trying to be straight and pass along my thinking to someone.

I never mentioned the K's you did, I was--mostly--talking about BMR, and those types. As a MM dealer I am comfortable with their parts. I think Griggs is nice from what I've seen but also hugely expensive, and I personally don't agree with some of the methods. I'd never chose to add the unsprung weight of a torque arm over a good 3 link or even something (for older cars) like a 5 link from Steeda. And I'm very familiar with torque arms, being I've f-bodies for years. In fact if I could change with any sort of ease my Camaro to a 3-link, I would.

 

[Sam Strano]

Thanks, Sam, and +1 on the compound data. The autocross compounds work wonders for TT or TA type competition, but they just don't seem to hold up long enough for sprint race formats...

That's my point, they can.... and have. Most Runoffs competitors were running them in their 20 lap races because they were faster. Now 90 degrees middle of the summer in a longer race, I'm right there with you.

 

[Rodeoflyer]

To each his own..... The last place I think "light" is good is on control arms or what they attach to. I've heard the same claims from f-body guys "no problem" only to see the k's fail.

Like anything not all versions of something are the alike. Doesn't mean I hate all K-members, but I can tell you the one I was involved with for the f-bodies is a lot different than any other that existed. The K's for SN95 that MM makes, I'd happy sell to someone for track use. Don't sell Griggs, and frankly even finding a decent picture of their stuff is about impossible. Can't speak to it, would guess given their reputation it's fine.

We need not get into the rules thing. NASA has what I think are some stupid rules too, even as low as CMC and don't get me started about their "points" for TT classes. Some of the things you get dinged the same amount of points for in comparison to others is insane. Rules exist in any series, nobody likes all of them.

Further, we all have our opinions and as long as those opinions have some basis in fact beyond "because I think so" then I don't think I'm doing a dis-service to anyone, by trying to be straight and pass along my thinking to someone.

I never mentioned the K's you did, I was--mostly--talking about BMR, and those types. As a MM dealer I am comfortable with their parts. I think Griggs is nice from what I've seen but also hugely expensive, and I personally don't agree with some of the methods. I'd never chose to add the unsprung weight of a torque arm over a good 3 link or even something (for older cars) like a 5 link from Steeda. And I'm very familiar with torque arms, being I've f-bodies for years. In fact if I could change with any sort of ease my Camaro to a 3-link, I would.

I agree with you on 95% of that Sam. Having a torque arm car, a 3 link car, and multiple 4 links in the past - i'll take a 3 link any day.

The Griggs stuff on my car came on it. I've slowly been swapping everything out so that it is all Maximum Motorsports. I'll never give Griggs a dime of my own money for multiple personal reasons, but I believe their HIGHLY overpriced products work well - not that my opinion means shit. Their results speak for themselves.

As far as rulebooks, I run TT with NASA think the rules are rubbish - but at least you are open to do things. That's a whole other debate - just had to get my dig in at the Spoiled Children Clowning Around.

As far as lightweight parts are concerned, I was speaking from both experience and public proof. There are shit parts out there from the UPR's and Granatelli's in the world. However, 95% of the aftermarket k-members on Mustangs that see road course duty are either Maximum or Griggs. American Iron is comprised of 90% Mustangs, with only some of the S197's running stock ones because they bought turn key FR500s'. The k-member on my car is the same k-member on the current American Iron champion's car - because he built them. None of them have failed because they are built properly. Lightweight doesn't mean light duty.

Your argument about lightweight k-members is just like Griggs saying that the S197 spindles are crap and are designed for failure. Again, the proof is public the FR500c and FR500s and their results are known.

This isn't me saying "because I think so". This is me saying it is a fact that there are literally hundreds of Mustangs road raced across the country on aftermarket k-members with no problems. It's not fair to the people that have done the math, testing, and fab work for decades to have you lump them in as unsafe or failure prone. The proof is out there.

 

[foolio2k4]

wow...awesome debates....So what do you guys think about the Agent 47 K-Member.

 

[Sam Strano]

And there are lots of cars that run oil you or I think is crap....and don't blow up. In fact for instance, I won't touch Mobil 1 because of issues I've witnessed. Do most have those problems? No, but even some who have can't believe it was the oil. Ok, that's up to them.

Same thing here. Ford is the one with the budget, not any of the rest of us. I can't imagine that given CAFE standards, cost of production and materials that they'd be using something way more massive than what they felt was necessary. Note that this does not mean I think all factory stiff is perfect.

You have here a part that not only locates the engine, but also takes a lot of load from the front control arms. And all K's bolt to the same locations as well. Take a 20 foot ladder, and lighten it. Could it "hold up"? Sure it could, I'd feel a lot better on one that didn't have holes drilled in it. Same argument can be made with drilled rotors. Lots of folks have them and don't explode 'em.... that's a stock sized brake that's been lightened. Would I run them? No, guessing you don't either.

All I'm saying is this: I'm not a fan of saving weight in an area that is subjected to those kind of loads.

 

[SoundGuyDave]

Sam,

I will agree with everything you've said here, but I think amplification on some points will be worthwhile...

The brake rotor analogy really isn't valid, since the holes aren't really there for weight reduction. They're there (putatively) for cooling. We all know that the holes create stress risers under thermal cycling that lead to cracking, which is why we don't run them in competition. A better analogy would be two-piece (floating hat) rotors. They retain all the mass of the friction ring to aid in heat management, but shave pounds in the hub area. Would you or I run them, class rules allowing? Oh, you bet we would.

K-members are kind of the same way. Yes, they locate the engine and provide attachment points for the front suspension, however the usage requirements of them are quite different between a mass-produced road car and a limited-use track car. Assuming that proper engineering processes have been followed (tubing size and material selection, gusseting and bracing, probably FEA studies), there's no reason that a track-oriented tubular K-member can't withstand the rigors of track driving. The stock production K-member has to withstand situations that a track-oriented piece simply won't. Potholes, curb hits, ungodly rough "roads", etc. are part of the design criteria for Ford. Also, cost of manufacture is a priority as well. It's simply cheaper to weld together two or three stamped pieces of metal than it is to cut, notch and weld up tubing on a jig. Also, I believe (don't know for sure) that the stock K-member has a crumple-zone function to dissipate energy in a front-end collision, which a track-oriented piece will not have to deal with (hopefully!).

Same ladder analogy: Yes, I would feel more comfortable on a non-lightened 20' ladder, BUT, if the original ladder was built from 3"x3" .120" wall high-carbon steel box tubing and 360* tig welded at all joints, I honestly wouldn't care if you decided to take a holesaw to the uprights every 6"...

If anybody is considering buying a K-member, it's a decision that shouldn't be taken lightly (pun intended). I would be a LOT more inclined to trust the design work of Griggs, Agent47 or Maximum Motorsports than I would UPR or Granatelli.

All that said, if it were easy to take weight out of our tutu-wearing sows, the K-member is probably one of the last things that would go. As it is, though, after all the "easy" weight reduction mods, it's still very hard to drop the car's weight under 3200lbs (without driver) without making some serious compromises somewhere. I would rather do a K-member from a company that actively races the S197 on track, than I would slapping on carbon doors without caging the car first.

 

[foolio2k4]

Well said to both

 

[Sam Strano]

Actually, drilling rotors is to drop rotational mass, not for cooling. If it was for cooling you can bet cars that have brake issues (like Cup cars) would be running them.

Porsche was the first to use drilled rotors on their 908/2 hillclimb cars in the 60's. But not on their road-racing cars. Why? Well, you are a lot less hard on brakes in a hillclimb... and they did it to cut the mass down where they thought they could get away with it. I learned this from an interview with Brian Redman fwiw.

So yes, it is about weight. It's be spun now that drilling lowers temps, but I've never see that actually be the case. You go gain surface for cooling, but also loose mass to absorb heat, and since pads fade, not rotors.... it doesn't really work that well.

As for street use vs. race use. Racing, well road racing/autox, puts far more lateral load into the car than street loads do. Yes, there aren't many potholes, but racetracks pile on their own abuse. We hop curbs. Ever seen cars run @ Sebring? Nelson Ledges in Ohio is a fast race track that's as bad as the worst 25% of paved or even chip-sealed public roads here in PA. And maybe that's part of my issue. I don't live in a nice temperate climate, but rather a place where road imperfections exist, on the street and on tracks.

I never said all K-members were junk. Saying I did because I didn't call out specific ones that aren't is like saying I think one's girlfriend is ugly because I didn't call her pretty.

I agree that if your ladder was made of 3x3" steel you could afford to cut so out. But again, many are assuming the stock part is miles and miles overbuilt. What normally is these days, on cars, or otherwise???

 

[SoundGuyDave]

Actually, drilling rotors is to drop rotational mass, not for cooling. If it was for cooling you can bet cars that have brake issues (like Cup cars) would be running them.

Porsche was the first to use drilled rotors on their 908/2 hillclimb cars in the 60's. But not on their road-racing cars. Why? Well, you are a lot less hard on brakes in a hillclimb... and they did it to cut the mass down where they thought they could get away with it. I learned this from an interview with Brian Redman fwiw.

Interesting!! You learn something new every day! Reducing mass on the friction ring of a rotor is seriously the wrong way to go about it... The rotor hat, however...

As for street use vs. race use. Racing, well road racing/autox, puts far more lateral load into the car than street loads do. Yes, there aren't many potholes, but racetracks pile on their own abuse. We hop curbs. Ever seen cars run @ Sebring? Nelson Ledges in Ohio is a fast race track that's as bad as the worst 25% of paved or even chip-sealed public roads here in PA. And maybe that's part of my issue. I don't live in a nice temperate climate, but rather a place where road imperfections exist, on the street and on tracks.

I'm out of Chicago, so I feel your pain! I'll still argue that a production-based component is engineered to withstand stresses orders of magnitude greater than we see on the race course. Hopping the curbs at Sebring? I'll raise you "suzy soccer mom" in her V6 mustang missing the driveway to her suburban home because she was texting... That impact (4" vertical) has a much higher impulse load than the curbs at Sebring, or Road America, or Gateway. At least the track curbs generally have shoulders to them! I will readily concede that a track car will exhibit higher average (RMS, for the math-friendly) loading than a road car, but lower peak loading.

I never said all K-members were junk. Saying I did because I didn't call out specific ones that aren't is like saying I think one's girlfriend is ugly because I didn't call her pretty.

Never said you did, but damn, that's some funny stuff right there!

I agree that if your ladder was made of 3x3" steel you could afford to cut so out. But again, many are assuming the stock part is miles and miles overbuilt. What normally is these days, on cars, or otherwise???

I hear you, there... Still, I've had the K-member off my car before, and it's wickedly overbuilt for what we need it to do. Still not a good project for a company who'se R&D department consists of a pair of Xerox machines, but not beyond the capability of a competent fab shop that is familiar with the rigors race cars are exposed to. Not saying that I'm going to order one any time soon, but... I think I can sum up by saying that replacing the K-member with a tubular version is not the first place that I would look to shave weight off the car, but not the last either. Bumper beams, anyone?

 

[LAK3RS]

I love this forum! I've never been big on the whole corner carving aspect of things, but this has been a great read and is filled with wealthful knowledge!