Shelby vs a Kirkham (aluminum)

[Allan A]

I was just wondering how much the copper suspension weighs with the copper body. If you add the copper suspension to the aluminum body with a aluminum steering shaft and stainless steel gas tank are you lighter than a viper?

Allan

[bret a ewing]

Doesn't Shel make a carbon fiber?

Wonder what that weighs?

[Geardaddy]

David,

Please post the weight differences between your car and a CSX

car. I think there are enough undecideds like myself on this

forum who appreciate as much information as possible, that may

sway our decision in one direction or the other.


Good Luck,
Tony Fischer

[David Kirkham]

Turk,

You stated, ”Your references BECAME the original car somewhere into your argument. If you mispoke that is OK. “

I did not misspeak.

There is some confusion here because of two different threads which are talking about the weights of various cars. On the other thread I stated:

“I was impresssssssed! I sat down and calculated the power to weight ratio of a 330 horsepower small block in one of our new lightweight cars to the power to weight ratio of an {original} (brackets added) big block...I was stunned--it was within 5%.”

I guess most people just don't understand how much power the 427's, (or should I say, the stroked monster 490+ cubic inch engines) are making today compared to the {original} (brackets added} 427’s. The original was FAST--today we are crazy—maybe a little bit too crazy.

As you can see there is a substantial difference between an {ORIGINAL} (brackets added) iron everything 427 at 2413 pounds and a Kirkham aluminum everything 427 at 2148. (The weight I quoted was 2413 pounds, clearly the weight I noted of CSX3104, an original car and not the weight of CSX 4238 which was also noted.)

Interestingly, a current CSX4238 car with aluminum heads and an iron block is almost exactly the same weight as our {original CSX3104} (brackets added). 3104 had iron heads on it when it was weighed, (it has aluminum heads now), and there is a 40 pound savings when you use aluminum heads so the numbers are very close which is quite interesting, considering CSX4238 has an aluminum differential in it and aluminum heads it should have a 60 pound weight advantage over an original car but the numbers indicate the cars are within 13 pounds of each other. I am not sure where the other weight is. (My only comment here on a CSX4000 car is that “interestingly” that is weight is “very close” to an original car’s weight.)

So, from the numbers I have gathered, a small block of {yesterday} (brackets added) is really the same weight as a lightweight big block of today. The lightweight big block of today may even be lighter. “Yesterday” refers to original cars and not to CSX 4000 cars.

So, it seems the British were right—to a point. The {original} (brackets added) car with iron heads, flywheel, and an iron block really did stink—I don’t think anyone disputes that.


If you want the mind altering acceleration of the {original car} (brackets added), then you really only need a 2050 pound car with a small block pumping out 363 to equal an original 427 with 425 horsepower in a 2400 pound car.

As you can clearly see, your comment, “Your references BECAME the original car somewhere into your argument. If you misspoke {sic} that is OK.” is incorrect. I did not misspeak.

You also said, “Not all Kirkhams have billet suspension pieces. I would say most DON'T.” You are incorrect in your statement. The vast majority of our cars are now delivered with the aluminum suspensions. We have sold approximately 400 427 cars and 50 289 cars to date. We switched from original style tubular steel suspensions at around serial number 200 on our cars. We have sold approximately 150 cars to Shelby—over 120 of them were sold to Shelby before serial number KMP200. I imagine our aluminum suspensions now outnumber our original suspensions by 2:1.

You stated, “If you were comparing the KMP to CSX3000, why are you weghing {sic} the CSX4308?” I simply offered the weight because we had the data and I figured someone might be interested. I never discussed the driving and handling of a CSX4000 car…I have never driven one so I could not comment.

Allan,

You posted, ” I was just wondering how much the copper suspension weighs with the copper body. If you add the copper suspension to the aluminum body with a aluminum steering shaft and stainless steel gas tank are you lighter than a viper?”

As I said in an earlier post, we have never sold a car with an aluminum steering shaft.

We have never made a copper suspension—although I must admit it would certainly look cool (all engineering studies aside). I think even our heavy copper-bodied car will all of the heavy iron engine components will not weight nearly as much as a Viper.

bret a ewing,

I do not know what Shelby is or is not making at this time. If Factory Five information would be of any value??? Dave Smith, once told me his carbon fiber body weighted 80 pounds. He was quite surprised when I told him our aluminum body was the same weight so there was no weight savings.

Geardaddy,

That is a GREAT idea. I think I will have to make a list. Sorry, it may take a while as we have 6 cars to deliver to California within the next week and a half—not to mention the cars heading east.

I will also post some of the part differences that I see.

David

[Slow8]

Whle I was at Kirkhams today, we weighed a CSX4xxx car minus engine and transmission. We weighed a Kirkham 427 with a steel frame minus engine and transmission and a Kirkham 427 with stainless frame and several lightweight goodies minus engine and trans. I did not write the numbers down, so I will let David post the numbers, but I was really surprised at how much less the Kirkhams weighed. The lightweight car actually had me (us) checking twice to make sure that the forks from the forklift were clear from the frame of the car and the full weight was on the scales. David went to great lengths to make sure that the cars had equal equipment (batteries, fuel regulators, nuts and bolts to hold the parts, etc...).

Kirkhams make a great product and work hard to make it better. Some people don't think that is the way to go but it makes sense to me.

[Turk]

David,
NOT TRUE again!!

There was no discussion by you on that thread at the time
rsimoes posted the following

It seems that the the Shelby is about 300 pounds heavier than the Kirkham. (aluminum body and block and rear on both)

I simply asked how that could be?

How can there be 300 lb. difference between the two cars?

I have no idea what other thread you might have been discussing the virtues of small blocks, or 289 cars or whether the Brits were right. I try not to read everything you write. I have high blood pressure.

I simply asked a question to another member after his post. No malice no sarcasm, nothing!

You jumped all over it with some elaborate explanations of different engines and aluminum parts etc.

That was NOT the question. Get it?

Go back and read for Christ's sake.

Since you keep coming back, tell me how a KMP weighs 300 pounds less than a Shelby? Hell you built both of them!!

Even with your aluminum mods, do you save 300 lbs. in suspension pieces? I don't think so.

I am not interested in all alloy car, like attempted to list. That is not what most of us have. Like you said you are "now" shipping.

I took off the all the alloy pieces you put on my car, and changed it all to Shelby. Does my car now weigh 300 pounds more?

No it does NOT.

It is also not true you never drove a CSX4000 car. You had my CSX4148 for sometime. Some one there drove it. Ask them if they drive better or worse.
I have no idea, again that wasn't my question. If you want to pick a fight with me, pick something good to fight about .I am not going to dignify you setting up different premises and arguing from both sides of your mouth at the same time.'
Enough!!

[David Kirkham]

Turk,

You stated, “There was no discussion by you on that thread at the time…” with regard to Rsimoes post, “It seems that the the {sic} Shelby is about 300 pounds heavier than the Kirkham (aluminum body and block and rear on both).”

Technically, you are correct there was no discussion by me at that time on the thread. We did, however, communicate with Risomes through emails, about these very weight issues. Otherwise, where would Risomes have gotten the information—except from us?

You then asked, “How can there be 300 lb. difference between the two cars?” Your question was posted after my post on the other thread where I detailed the weights of the different cars and I imagine you read it and I answered accordingly. If you didn’t read it, certainly others did and could have easily been confused.

Then you stated, “Since you keep coming back, tell me how a KMP weighs 300 pounds less than a Shelby? Hell you built both of them!!” We do not build Shelbys and we have never claimed to. Our cars are very different from Shelby’s cars with the exception of the frame and body. Shelby does not use our suspensions. As you very well know, Shelby only buys frames and bodies from us and on rare occasions a few other parts. My comments, as I described above, were not directed at the current CSX4000 cars, but rather at original CSX3000 cars. I simply posted the weights of the cars we have weighed and detailed the differences (iron blocks, heads, etc.) so people could see exactly what was going on.

You then stated, “Even with your aluminum mods, do you save 300 lbs. in suspension pieces? I don't think so.” I NEVER claimed a 300 pound weight savings over an original car with our suspension alone. I have only claimed an 80-100 pound weight saving with our suspensions and I estimated a 150 pound savings overall with all of our modifications. (The 20 pound difference being due to ongoing refinements in weight reduction). As I said above, “I have only said I think our car, not counting the engine and transmission, is probably 150 pounds lighter than an original car.” I have never claimed our suspensions make our car 300 pounds lighter.

You stated, “It is also not true you never drove a CSX4000 car. You had my CSX4148 for sometime. Some one there drove it. Ask them if they drive better or worse.” You are incorrect. No one here at Kirkham Motorsports drove your car. If you remember correctly, we even urged you not to drive your car as, in our opinion, we believed certain repairs needed to be made before it could be safely driven. You elected to send the car elsewhere for review and we shipped it without ever driving it. Again, I do not believe it would be proper to comment on the handling of a car I have not driven.

You stated, (with reference to our aluminum suspensions), “That is not what most of us have. Like you said you are "now" shipping.” Again, you are incorrect in your statement. For the past 2 years we have only sold 1-2 original type suspensions/year. Our aluminum suspensions outnumber original type suspension by about 2:1. At our current sales rate, billet aluminum suspensions will shortly, outnumber original type suspensions by 3:1.

David

[Anthony]

David, not that I want be part of this discussion, but have you installed any of David Kee's aluminum cased toploader trannys?

[David Kirkham]

Anthony,

I have not yet driven a David Kee aluminum top loader transmission, so I can't comment. I have driven quite a few of his iron transmissions and they are great.

I am going to build myself a new car shortly, and I will be using the new 5 speed Tremec 600 transmission in it. I really like the gear splits in the tranny and it weighs the same as an iron top loader. The aluminum top loader is about 20 pounds lighter.

David

[Anthony]

David,

I see all these people talking about the new TKO600. But, the gear spreads (2.87 first) are really similar to, just a touch wider, than a wide ratio toploader (2.78 first), but with an overdrive.

I'm not a racer, no experience other than Run-n-gun. I have a wide ratio TL with a 3.07 rear, and I think the wide ratio TL is just a little too wide. I'm seriously considering changing to a true close ratio tranny , either a CR toploader (maybe one of Kee's aluminum versions), or a custom CR jerico/G-force 5 speed, keeping the 3.07 rear in either case.

I just think the WR toploader gears are spread alittle too wide, and you're really not gaining anything with the TKO600, except for an overdrive, which you really don't need , as to gear the cobra correctly with first gear (2.87), you will need to run sometyhing like a 2.88 or 3.07 rear otherwise first gear is geared too low, and then you probably don't need overdrive with those rear ratio's.

To each his own.

[Anthony]

David,

Have you raced a cobra with a wide ratio toploader yet? I would think it will be very similar to the new TKO600.

[Excaliber]

Anthony, I love the close ratio gears on my top loader, BUT, I'm not crazy about the 1st gear ratio being substantially higher than in the wide ratio. With a 3.07 rear gear and a close ratio I calculate you could do over 70 mph in 1st gear alone! A ratio that high is going to be hard on your clutch (by the way).

The original Comp cars ran a close ratio, but most of the time ran a pretty low rear gear, like 3.73.

[David Kirkham]

Anthony,

I think you would be really unhappy with a 3:07 gear and a close ratio transmission. I think you would be able to go even over 70 mph in first gear. You would really have to slip the clutch to get it to move anywhere.

I really like the Tremec 600 and wide ratio transmissions in our cars. I do not like the close ratio transmissions at all in our cars. Of course, on the track, however, you would want to have a close ratio because you are not really starting from a stop so a longer first gear is not a problem. Starting from stop signs and stop lights would get to be pretty annoying with a close ratio and a 3:07 differential.

In the end, however, only you can decide what gears you like and are happy with for your particular style of driving.

David

[Turk]

OK David.

Whatever..

TURK

[Anthony]

David, Ernie

I believe some of the comp cars ran a CR toploader with 3.31 rears (first gear multiplication = 7.68). I am currently running a M21 ( 2.20 first gear) with 3.36 rears in my 442, and it's OK ( first gear multiplication = 7.39) .

With my cobra, I may try McLeod's soft-loc clutch, made to slip for launching, so I think it will be OK even if I go with a CR toploader ( 2.32 first) with a 3.07 rear (first gear multiplication = 7.12) . Obviously the 3.07 rear is nice for cruising.

If I do it, I'll try to remember to let you know how it works out.

If a cobra with a CR toploader and 3.54 rears ( first gear multiplication = 8.21) can do 65 mph in first @ 6500 rpms, then with 3.07 rears, it should be able to run 75 mph in first or reverse.

[Excaliber]

No doubt they would vary the rear gear for the track in question. I'm sure the 3.73, for instance, would be to low for long straight away tracks. But it is a number I've heard in reference to the Comp cars. If I had my choice, 3.5 rear with a close ratio!

Sure 5 speed is great, but I kind of like that "original" thing I got going on with this car. Maybe the next one...

You can bet the Dragon Snakes ran down in the 4's for a rear gear.

[ToyCollector]

3:42:1 is the way to go if running a 4 speed. Still happy with it.

[David Kirkham]

We have found most customers are happiest with a 3:42 for both the top loader and the new Tremec 600. Some are happier with a 3:31 and a top loader and some are happier with a 3:42. With the Tremec 600, most are happiest with the 3:42.

David