Tubular K-member points question

[TurboShortBus]

Just out of curiosity, I have a question about the points for Suspension/Brakes/Chassis rule 14:

 

14) Tubular K(cross)-members that do not change the location of the lower control arms +2

 

At least in the Mustang community (which is the only place where I'm remotely smart), the usual reasons for installing aftermarket tubular K-members, not necessarily in this order, are:

 

1. Less weight

2. Some are slotted for engine setback (but there are already points for this if setback exceeds 1")

3. So you can find the bolts and sockets that you inevitably drop from above

4. Helps with header clearance if you run longtubes

5. Reduced overall profanity

 

At first glance, this rule seems like a double-whammy to me, since points would already be assessed for the weight loss, based on the Weight Reduction section of the rules. At +1 point per 15 lb loss, there would be up to +2 points for the tubular K member weight loss, and then the +2 per 14) above. I can understand assessing more points for K-members that change the location of the suspension arms per 13), but what about K-members that don't move the mounting points of suspension parts, as noted in 14)? Also, if the steering rack mounts move around with an aftermarket K-member, they should be assessed +2 points per 15); however, this won't make a points difference if a typical set of offset rack bushings or bumpsteer kit is already being used.

 

Is there another performance advantage, other than front end weight loss, that I'm overlooking? True, tubular K-members allow you to remove about 25-30 lbs from the front of the car (the magazine ads that say "100 lbs off the front end with our K-member" are crap, as the stock SN95 Mustang K-member is only about 52 lbs), add that ballast to the rear, and maintain the same total weight with a better front/rear balance; however, ditching 50 lbs worth of HVAC equipment from the front of the car and putting that much ballast in the rear of the car makes a slightly bigger difference and is worth 0 points. I'm sure that many street-driven TT cars would rather keep their HVAC and use the tubular K-member. Or, are there bigger advantages with cars other than Mustangs? Like I said, I'm only Mustang-smart.

 

Thoughts?

 

Mark

Edited April 24, 2009 by Guest

[kbrew8991]

that sounds like a leftover from the points-for-parts days to me....

[Joshua]

Aside from the weight benefit, there's rigidity to be gained. However, since you can now stiffen up the front end with a chassis brace for 0 pts, that's not much argument against them. You make a good argument that changing engine mounting location, suspension pickup points and rack attachment location also incur points, so the tubular K-member results in "double" points assessment.

 

Is a K-member the same as a subframe? If so, and if they're allowed for 2010, I could drop 10 pounds off the front of my car with a $1k tubular subframe from V8 Roadsters .

[kbrew8991]

control arms mount to the outboard ends, engine mounts to the middle... you tell me

[TurboShortBus]

In the case of a Mustang, I seriously doubt that there is any rigidity to be gained with an aftermarket tubular K-member as compared to the stock, stamped steel monster that's under there. Also, typical Mustang tubular K-members are about $300-400. It might be different in Miata-land, though. I don't see a K-member being considered a subframe in either case, as it's just a big, common bracket that connects the suspension and engine to the front subframe.

 

I have a side-by-side comparison photo of my stock 1994 GT K-member and the aftermarket K-member that I replaced it with at home. I'll post it tonight.

 

If we're talking about losing 10 lbs for $1000, then you can already easily do that with a high-buck set of wheels with no questions asked!

 

Mark

[Trevor57]

This is why I have one sitting in my garage.

[TurboShortBus]

Here are photos, as promised, for the unStanged: the dirty yellow one is a stock 1994 GT K-member (~51 lbs) from my convertible, while the shiny black one is an AJE racing mild steel tubular K-member (~23 lbs). I seriously doubt that there's an appreciable increase in rigidity, if any.

 

 

 

 

Mark

[Trevor57]

If you really want to bitch about points how about this. The 94-95 is in the same base class as 96-98.

[TurboShortBus]

If you really want to bitch about points how about this. The 94-95 is in the same base class as 96-98.

Nah, I'm OK with that. The 94-95 5.0L Mustang GT was every bit as much of a heavy, gutless pig as the 96-98 4.6L SOHC Mustang GT. I'd still take the 5.0L over the non-PI 4.6L SOHC any day. It will take a bunch of work to get them down to the 3075 lb base weight, though. This is probably a fun topic for another thread...

 

Mark

[Joshua]

If we're talking about losing 10 lbs for $1000, then you can already easily do that with a high-buck set of wheels with no questions asked!

It wasn't clear in my earlier post, but 10lbs for $1k will never happen.

[TurboShortBus]

It wasn't clear in my earlier post, but 10lbs for $1k will never happen.

Maybe not in your car and definitely not in my car, but I'll bet that some crackhead with a bottomless wallet has done it before! lol

 

Now that I think of it, I was in Powered By Ford about 10 years ago when a tubby Pro 5.0 Mustang drag racer was there buying a $2500 titanium bellhousing because he did not want to lose any weight off of his 300+ lb ass. yeeeehaw good buddy

 

Mark

[IGZOSTD]

Thanks for bringing up another rule for me to b!+(h about.

I'm going through the very same thing and problem is , I don't think I'll even lose 25 lbs .But you could send 600 on a light driveshaft and lose a lot of wt. on a Mustang and this would be worth the wt. pt.

The exhaust rules are some of the worst , and senseless

But we should all be of good cheer -- at seasons end the rules will change yet again

[QUASAR]

In fbody land most run the stock k member. It has proven to be the strongest. People have actually broken aftermarket tubular units from the side loads of road racing. The intent of the design of these things (at least on muscle cars) come from drag racing vendors and they only care about being able to go straight and be light. Most fbodys run stock k member and stock control arms because of this. There is one aftermarket tubular piece for us that uses two tubes to connect across the middle instead of one and one guy in AI is using it with sucess last I heard.

 

Its not high on the priority list but it would be nice for some of the points you mentioned including easier access to everything under there.

[TurboShortBus]

While any given aftermarket K-member may be stronger than, no stronger than, or less strong than a stock one, and while that is a fine debate topic, I'm just curious as to why there seems to be a double-whammy on the points assessment if the suspension geometry and mounting points do not change, and the only performance advantage (that I can tell) comes from weight reduction.

 

Mark

[IGZOSTD]

Agreed

[RodeoFlyer]

Steve -

 

I believe I know which k-member you are installing, as I have the same one. It's a 18lb weight savings.

 

+2 for a piece that removes weight from the front of a Mustang is worth it IMO. There are plenty of other areas we can bitch about points.

[IGZOSTD]

Matt, It's Agent 47. Just finished taking the last 200lbs of unnecessary's out of the car. No more heat , no more air , no more rock and roll

[TurboShortBus]

+2 for a piece that removes weight from the front of a Mustang is worth it IMO. There are plenty of other areas we can bitch about points.

Well, as it stands right now, it's more like +3 to +4 if you don't replace the weight anywhere in the car, which is the double-whammy that I'm referring to. I don't see this as being any different than paying a combination of weight loss and modification points (there are currently no points for the latter) for removing 50 lbs of AC gear from the front of the car.

 

I'm not bitching about points here; other people are. I'm just looking for an explanation or a reason that I might be overlooking, that's all. But, if this is just a leftover item that can be cleaned up, then there's no harm in that.

 

As for me, I don't have a tubular K member in my TT Mustang, nor is one on my shopping list.

 

Mark

[Trevor57]

In my experience it is VERY difficult even to get down to base weight. Even if I wasn't a fat-ass. My car weighs 3078 by itself. That is a mostly stock 95, with one race seat, fully gutted from the b pillar back, no ac, no smog. So until you get the car around 2900 lbs, you won't really be getting double hit on points.

[TurboShortBus]

In my experience it is VERY difficult even to get down to base weight.

Nah, not at all, depending on what you start with.

 

As an example, my 2004 Mustang GT has a listed base weight of 3273 lbs. With all of my interior trim removed except for the dashboard and HVAC, my minimum competition weight is 3185 lbs (with me and no gas, and I'm only worth 187 lbs). So, it was very easy for me to get below base weight and, in this case, the K-member points would be a double hit.

 

While my examples might be Mustang-specific, my overall question applies to any car.

 

Mark

[IGZOSTD]

When I first stared, all I had out of the car was the spare tire , cats and air box , with wheels and dot slicks . I was still way over min. wt. at 3645lbs. with me and 7 gal. of gas After taking out door panels, door glass, head liner and all interior plastic around the windows front and rear seats and seat belts then adding in a full cage with NASCAR door bars right & left I was 50lbs under min of 3450 with 7 gal. of gas and me . This is with everything still behind the dash, and a stereo and rear speakers heat and a/c. So I think it was pretty easy to get to min. The hard part is to get much lighter is going to start getting tough. Carbon doors 50lbs, trunk about 16lbs. hood I haven't weighted yet. there's still a lot of small things up front and the stock bumper brace's

Keep in mind I'm going as light as the wallet allows and if I have to fill the tank and ballast that's great .

Mark I still agree with you that a standard k member replacement is just a lighter weight component. Lighter wheels and flywheel are more important and free as to points.

[32EVOIX]

I totally agree with you guys and although I don’t know much about the Mustang parts I can certainly attest to my Evo. My car has a 3 point front strut tower brace stock. It is also very heavy for a small car minimum competition weight 3263 lbs with the weight distribution 60/40. I would like to replace the stock piece with a light weight piece but I cannot without taking the points. The same goes for under the car braces, which the car has stock. They are all heavy steel pieces, and replacing them would offer no more or less bracing but rather weight savings.

[kbrew8991]

while I suspect this is a hold over from the points-for-parts era... never forget

 

Pick your frog and live with the warts

[IGZOSTD]

That's ok Ken as I have never been forced to kiss a frog

[TurboShortBus]

Can we get an official to weigh in here?

 

Mark