Do all 1st gen tubs weigh the same?

T

TomL

New member
I've seen some anecdotal evidence that early first generation RX-7 tubs (1979-80) are a bit (50-100 lbs) lighter than the later models. Most of the ITA/7 cars that I've seen that are close to minimum weight (adjusting for differences in driver weight) seem to be based on early tubs. No obvious reason this should be true. Visually they look the same except for some bracing near the rear wheel arches that is found on the early cars.

So, has anyone ever actually weighed both and determined if there is actually a difference, and if so how much?

Thanks
 
I've never seen any proof, and at 30 years old it would be hard to come by. Generally speaking I think the 79-80 cars are lighter, but also remember that the pickup points changed in 84-85 which I think is a greater advantage.

There will obviously be a weight difference in sunroof and non-sunroof cars.

The biggest and most often overlooked bit of weight savings in first gen RX-7's though is wiring. The whole wiring harness weighs OVER 50 pounds, and you actually need very little of it, especially if running data or aftermarket gauges.
 
The only thing i can find is, all the first gen's with 12a's were bunched into one group
that the curb weight was 2345 lbs. and one's with an automatic were 2380 lbs.
As was stated the sun roof cars weight was more due to the extra bracing in the roof area, plus the mechanics of the roof its self.
There was some additional bracing in the rear as Tom said. i think it was 83 and up.
the floor pans were also different from the back of the door edge to the spare tire well.
The lower valance on the 79/80 was lighter as it was just a stamped piece of thin sheetmetal and mazda then went to the rubber wrap around valance and bumper cover.
One other thing, i don't remember the year but mazda also changed the diameter
of the rear axles and made them more heavy than the earlier years. the trans in the 79/80 was about five pounds lighter due to the shift tower design.
My memory check has pretty much gone blank at this point, I know that there were several other small things that made the car lighter, maybe it will come to me about three A.M. in the morning.
Oh yea!!! the front struts on the early cars were smaller in diameter and weight was less than later cars and the brake caliper brackets were lighter but would flex. OK back to sleep now.
 
Chris Taylor said:
I've never seen any proof, and at 30 years old it would be hard to come by. Generally speaking I think the 79-80 cars are lighter, but also remember that the pickup points changed in 84-85 which I think is a greater advantage.

There will obviously be a weight difference in sunroof and non-sunroof cars.

The biggest and most often overlooked bit of weight savings in first gen RX-7's though is wiring. The whole wiring harness weighs OVER 50 pounds, and you actually need very little of it, especially if running data or aftermarket gauges.
Click to expand...

I don't believe it is legal to remove the wiring, only repair it if needed. I would love to be wrong on this.:)
 
Thanks guys.

Joe - If you remember all that, I think you you're under hypnotic recall already - no sleep needed.

Chris - I've never heard of that the pickup points were changed on the later models. Are you talking about front or rear, and in what direction are they moved? If they're in the front, could you move the points by swapping crossmembers and tension rod brackets? 50 pounds for a wiring harness? I've seen one that big on some cars (my Nissan, for example), but the one in my '79 RX7 isn't much over 10. Are the later ones that much heavier?
 
Tom, the rear four link pick up points on the tub were moved up. also the rear subframe was changed to add travel to the rear.
 
The pick up points on the rear trailing arms were moved on the body. 84-85 only. The bracket lowers the frt of the arm approx 1 inch. Wrong direction when lowering the car. The tubs were 2 pieces of sheet metal thick at the rear upper pickups with a brace on the floor in 79-80 chassis. Later chassis are three pieces thick at that point which is why later cars rust out more at the seat belt mounts. Lots of places for moisture to sit. I dont tghink the a pillars were as thick early on either and sunroof frames/brackets are on all chassis after 81 weather it has one or not. Stupid things you learn when stripping cars for the scrap yards.
 
I'm surprised that Dick has not checked in... I know he chose a 79/80 for a reason on his rotisserie build and based on my conversions with Dick he knows the differences down to a pound or less. The man is a machine when it comes to this stuff!

If you are not on it already rx7club.com is an awesome resource for these cars and has a number of really good guys on it.

I do know that "everyone says" the early cars are lighter, but my knowledge stops there... I do know that I don't like the look of the rear of these cars, but maybe it could grow on me...
 
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