Z-Car weight/ITS

I

irondragon

New member
To WIMC:
Who ever made it possible to have the competition weight of a Datsun 280Z drop from 2750+\- to 2505??
Would this person/group please show up in my shop and explain how I can excise this much weight from the car without destroying the structural integrity. And then be willing to drive the car.
Or, would this person/group like to address the idea that this weight readjustment was nothing more than pandering to the owners of younger ITS cars who did not want to have their power restricted.
If I am wrong in my analysis of what has happened, then tell me.
Let's have a bit of intellectual honesty here. Who did this??
Bill Miskoe - Iron Dragon Racing - Datsun 280Z - ITS Class winner at Nelson Ledges 12 Hour 2006
 
That's a rather confrontational post given that the weight change was designed to help you.

The "who" who did this is via an ITAC recommendation to the CRB if I understand it correctly. They ran the Z cars through the new process, came up with a weight based on expected power output and some subjective adders/deductions.

You got a significant break, and even if it is not totally acheivable, I'm trying to see why you should be upset about this? The only car that fell outside the performance parameters (in S) of the ITAC's process was the BMW 325, and it got hit with an SIR instead of weight. So, I'm not sure which of the younger cars benefited from the weight change (reduction) to your car?
 
I would be more than happy to have an unachievable low weight thrown at my car...It may take some cage restructuring but it could be done...the 280 is a solid car and any weight you can get out will only make your brakes happier.
 
280Z: 1975-1978
Source: Nissan Motors

By the mid-70's, emissions regulations became stricter and it took increasingly complex technology to meet them. As a result, Nissan chose to boost the Z's engine displacement and add a version of Bosch's L-Jetronic fuel injection, creating the 1975 280Z. The suspension was also upgraded to match the increased power. Produced for four years, the 280Z added a five-speed overdrive transmission in 1977 and in 1978, a special edition Black Pearl was offered, featuring red and silver accent stripes, rear window louvers and dual racing mirrors.Engine
Valve Gear Single Overhead Cam
Type 6 - cylinder inline
Horsepower 149bhp @ 5,600 rpm
Torque 163lb ft @ 4,400 rpm
Fuel System Electric Fuel Pump, Bosch L-Jetronic fuel injection
DriveTrain
Transmission 5-speed manual or 4-speed manual
Chassis Curb weight 2,800 lbs.
Dimensions
Wheelbase 102.6 in. (2+2)
Length 173.2 in. (two-seater) [/b]
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I have to believe it is possible to get dam close I know the bumpers are a big issue. R 180 and a 4 speed would help 280 Z struts are a lot heavier than the 240z units The Hatchs on the 240 are the same but are lighter. Early glass is lighter also.
 
Tnx to all for your replies.
The weight reduction for Z-cars may have been intended to help me, but as the new weight is unachievable it does not. Perhaps I should have been delighted by the intention but I am not.
I believe that it was done in an attempt to keep all cars in the class at about the same power to weight ratio.
Newer cars with higher p/w ratios have arrived and it seems ITAC wanted to keep them in ITS without restricting their power. Accordingly, some cars had their weights lowered.
Good enough if it could be accomplished, but I've been around long enough in the metal fabricating business to know that weight doesn't just go away because someone writes a new number in a box.
My original post asked the people responsible to show me how I could remove 250 pds from the car and maintain its structural integrity. None of the replies have provided an answer, even though some express dismay that I would object to what has been done.
Until someone actually proves that it can be done I think the process is flawed.
Why not deal with the p/w ratio problem differently: either restrict power ( which I don't favour as it is hard to monitor) or, more realistically, ballast up the more powerful cars which is not hard to do or to monitor.
Why is the p/w ratio issue not being dealt with in this manner??
Best Regards - Bill Miskoe Iron Dragon Racing
 
Bill, that's better.

The fact is that it is impossible to get teh pw/wt ratio perfect for all cars in the class. I think the target is in the 15:1 range, and the ITAC did a great job in my view in getting the 944s, the 325 (now restricted), the 240z and the RX7 balanced at that point.

There are some cars that 15:1 just won't work completely for because the weight just isn't possible or the power just isn't there (see 944 8v discussion), and unfortunately that is where the no guarantee of competiveness comes in. I'm somewhat in that boat myself.

I bet you can get 100 lbs off the 280z and with the power it makes, you should be very competitive with the other makes in S. The big problem was the unrestricted 325. While I would have preferred it got weight, the SIR and now the impending move of most of these cars to ITR should have fixed this.
 
Tnx to all for your replies.
The weight reduction for Z-cars may have been intended to help me, but as the new weight is unachievable it does not. Perhaps I should have been delighted by the intention but I am not.
Best Regards - Bill Miskoe Iron Dragon Racing [/b]
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What have you done in an attempt to acheive the lowest possble weight? More importantly, how close have you come?

I find your comments disengenious, because it's stated as an absolute....if you can't make minimum, it doesn't help....but if you can make less than the old minimum, it has to help.

There's gotta be a middle ground, but you're not appreciating that.

Oh, and "Pandering"?? Please.......read my sig....my car is a thousand times more popular than yours and buckets of guys say the new weight is unacheivable, and, even if it were, it wouldn't be nearly enough...I have the original poster child for what your'e getting at...so don't say that I "don't get it", and am pandering.
 
2430# for a 240Z, 2505 for a 280Z, that'd be a delta of 75 lbs. I don't think there's 75 lbs more metal in a 280Z tub, having cut up both 240Z's and 280Z's and actually having welded 1/2 of one to 1/2 of the other. It'd be close, but I think with the right cage design and some work it can be done (like are you using a factory windshield or aftermarket? Some aftermarket ones weigh as much as 11 lbs less. Oops, you didn't hear that from me).

Personally, I always hired little drivers. :eclipsee_steering:
 
K, I know the struts are heavier in a 280 and the 75 lbs is likely the bumpers. The deck lid(hatch) can be about 8 lbs different between an early 240 and late 240 but I am not sure how it compares for the 280...Cage is a good question and removal of ALL the extra sound uncoat is a must.
 
K, Joe, are the 240z/260z/early 280z tubs essentially the same?
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the 69/70 tub is the lightest includind suspension bits. the mid 70 to late 72 was a little heavier than the early cars mostly due to heavier parts used in the suspension, the late 72 early 73 cars have better metal in the rear suspension areas that added weight. I have never had an issue getting a late car down to the current weight for ITS with a proper cage. The early 260 I am sure is the same at the latest 240. I think I stll have all the supp/addons to the factory books in my shop.

Joe

Edit, I did forget the suspension in the 280 is heavier than the 240. I am betting a person could save about 35 to 40 labs running the early strut housings.
 
240-260-280Z tubs are similar.
However the 280's have federally mandated bumpers which are considerably heavier, along with some framing reinforcements to support them.
This is weight that can't be taken out. Original bumpers are required in ITs and the frame elements are just too much built-in to be removed.
Bill
 
Bill sent me this is a private e-mail as well so I will answer here.

Bill, you ask for specifics on hwo to get your car down to weight. Without any of us seeing it at a shop, I am not sure how you can expect a real answer...but try this:

1. What weight is the car at now?
2. How much do you weigh?
3. How much gas do you run?
4. What struts are you running?
5. What exhaust are you running?
6. Provide a picture of the cage so some experts can see if there are 'extra' bars in there
7. How much enduro stuff do you run in the car all the time
8. How much do your wheels weigh? What tires do you run?
9. Is 100% of the undercoating gone?
10. Do you run a cell? How big?

All of these are designed to prove/disprove any amount of weight than come out.

I am sure there are plenty of other questions to ask. You say in your e-mail to me that you had hoped the ITAC would make new recommendations on weights for your car. It would seem like you want, what you perceive to be, a more attainable weight. But what is the net/net? Nothing. If you are at 2750 in a 280Z, I think you have a lot of weight to remove. If there is 100lbs of difference in bumpers and chassis, that still brings the car in well under 2600...

Having said all that, just like the 944 excersize, if this car CAN'T get close to minimum, it should be considered for ITA IMHO.
 
I began this rant to try to bring some daylight into the swamp of how the p/w ratio concerns were being resolved. So I'm happy with the resulting discussions and have learned a lot.
But the questions which I still find left unanswered are these:
-how were the Z-car weights determined?
-is there a 280Z which is both class compliant and structurally competent which weighs 2505 pds?
-why was the decision made to encourage possibly illegal andf unsafe weight removal from low powered cars, rather than to ballast up high powered ones?

It is not a question of how much weight I have stripped out of my car but rather of whether the specified weight is attainable at all. If not then the process is flawed and the resulting p/w ratios are phony.

Several people have been very helpful with suggestions for weight removal, and I appreciate them. Some are applicable to my racing situation and some not. For instance, the car is a 12-hour enduro racer and therefore I have opted for more fuel capacity than a sprint racer would choose.
But I am a bit leery about taking out cage elements. Cage design is a bit of a guesswork job at best as no one really knows what impact loads will be applied to which pieces. So I don't like p/w ratio solutions that encourage people to lighten cars by removing structural elements.
My whole purpose was to try to get ITAC to rethink the p/w ratio problems and to create realistic solutions.
One reply indicated that the writer thought I was confrontational and this is correct. Fact is I see this as a situation which needed to be confronted and I have attempted to do it in an agressive but polite way with no name calling or derogatory statements about individuals.
Best Regards - Bill Miskoe Iron Dragon Racing
 
Bill - please address the questions I asked. I have never sat in your car but I have raced against it and seen it. I wouldn't classify it as a 100% sprint-car effort. THAT is what these specs rely on. If you can get into the low 2500's with a new (and safe) build, it is fine as is. Just because your enduro-centric car is overweight has no bearing on the issue actually. In answering the questions for us, we will get an idea of what is left. 2 Z-car guys have weighed in expressing that they are confident the weight is possible. Your expereince with your car may be contrary, but lets learn why.

- NOBODY is suggesting you sacrifice safety but the fact remains that there are plenty of 'overbuilt' cages out there - and while that is great, it can't be a classification data point.

You have a choice. 2505 in ITS or around 2900 in ITA (should it be determined that your make/model can't make weight). Some guys consider adding weight to there cars to be a safety issue as well. Reducing the min weights to the low end on some cars is a lot easier that telling a lot of cars they have to add weight. Bottom line again - if the 280Z can't hit in the area of that weight, it should be considered for a move (and that day is the day I stary building one - Hello, Rebello?, Top Tech? - I love those cars.)

Rants are great but lets fill in the blanks on your prep level and current weight before we go marching off into the night with our pitchforks.
 
Bill - please address the questions I asked. I have never sat in your car but I have raced against it and seen it. I wouldn't classify it as a 100% sprint-car effort. THAT is what these specs rely on. If you can get into the low 2500's with a new (and safe) build, it is fine as is. Just because your enduro-centric car is overweight has no bearing on the issue actually. In answering the questions for us, we will get an idea of what is left. 2 Z-car guys have weighed in expressing that they are confident the weight is possible. Your expereince with your car may be contrary, but lets learn why.

- NOBODY is suggesting you sacrifice safety but the fact remains that there are plenty of 'overbuilt' cages out there - and while that is great, it can't be a classification data point.

You have a choice. 2505 in ITS or around 2900 in ITA (should it be determined that your make/model can't make weight). Some guys consider adding weight to there cars to be a safety issue as well. Reducing the min weights to the low end on some cars is a lot easier that telling a lot of cars they have to add weight. Bottom line again - if the 280Z can't hit in the area of that weight, it should be considered for a move (and that day is the day I stary building one - Hello, Rebello?, Top Tech? - I love those cars.)

Rants are great but lets fill in the blanks on your prep level and current weight before we go marching off into the night with our pitchforks.
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Bill, Your right.....When I was consulted I said that the weight was too light....NOt because it couldn't be made or that it was unsafe but because I felt I could get better HP than the P/W they were shooting for. I am still convinced even with out an ECU it could make the HP to get the job done in that car. Of all the z's classed I feel the 280 has the best shot at front runner status.....Maybe I'm stupid or maybe I am good who knows....but the car is 400cc's bigger has better valve area a good head better cam profile, EFI, 5 speeds better rear brakes and only has to be 75 lbs heavier....No brainer to me.....WIll not beat a non restricted E36 but is gonna run at the pointy end if done correctly.
 
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