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R180 vs R200, and more...


Guest Anonymous

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Guest Anonymous

Hi.

 

I have a '70 240Z begging for a V8. Unlike most people here, I've decided a Ford 302/347 is the way to go.

 

I have a question about rearends. I couldn't find just the right forum for that, so I decided the almost all encompassing "Tech Board" would be the right place. Hopefully...

 

Part of my quest is in keeping the car very light. I'm shooting for a finished empty weight of under 2200lb.

 

That in mind, how many of you are successfully using R180s (with LSD) in V8 swaps? My car will never be launched on slicks, but it will be auto-xed and (probably) open-tracked on race compound radials.

 

I'm also a bit worried about the effects of speed on the drivetrain. When I dynoed my car, I decided to make the pulls in 3rd gear because I'm not too comfortable with the general condition of the car yet. We've already had a vintage car destroy a driveshaft on our dyno at 120+mph, and it was a very scary experience.

 

Ideally I'd want a car I can safely take to 150mph whenever I want to. Will the stock halfshafts, hubs, etc take that sort of speed? If not, what should I do?

 

Thanks very much for any and all comments.

 

 

 

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Michael Sen-Roy

Houston Performance

281-893-6080

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The case of the R180 isn't the issue. Bob Sharp and others commented to this issue and what the real problem was when they were running R180s in the early days of racing. Heat is one big factor. The other is Ujoints. You always hear people refer to half shaft failures, but most of the time it isn't the actual half shaft, but the Ujoint. Heat related cracks in the case is the other, cooking the internals and causing bearing failures. Sounds like you are gonna be doing the same type of events I'm doing, so here is what I have done so far:

 

I'm using the beefy R200 rear out of the 300ZXT with the factory LSD and 3:7 gears. I'm using 280ZX rear half shafts with Spicer Ujoints for now, and if this rear (Which has lasted two cars, and won me a championship in the regional Solo2 events) holds up, I plan to plumb in a Diff cooler and fabricate some safety hoops for the axle shaxts so they won't take out the brake lines if they fail. The cooler will address heat related stress cracks in the diff case that plagued Sharp and others in the early days, and the Spicer joints will help combat the failed axle issue. IF I run into problems, I'll be looking into other alternatives for axles first, then other options for rears second...

 

I have no plans of serious drag racing, but will take it to the strip with street tires, so I won't put as much stress on the rear as running drag radials or full on drag slicks. I am running a 265-50-15 on the rear, which will put a little more stress on the axle shafts though. I might run a road race slick, or a BFG R1 type tire for some of the high speed event, but like yourself, I'm gonna be road coursing and autoXing it, with the occassional hill climb or top end run.

 

Glad to see someone doing the 302 swap. I think the Ford is a very formidable option in the Swap arena!

 

Mike

 

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"I will not be a spectator in the sport of life!"

mjk

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Guest Anonymous

It had occured to me that 180mm is a fairly large r&p for such a light car. This is one reason I didn't think a swap was necessary. The heat issue did _not_ occur to me though, thanks for pointing that out.

 

So, looks like I'll probably take the weight penalty in order to make the car a little more reliable. Next question, then, what's the tallest R200 gear ratio available? I want something tall so 2nd gear goes a long way in auto-xing.

 

I have excellent access to Ford knowledge and parts. They're lighter, smaller, etc. It seemed like the logical thing to put into a small, light car.

 

Thanks again!

 

 

 

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Michael Sen-Roy

Houston Performance

281-893-6080

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Guest Anonymous

How did you get your car down to 2500lbs?

My car weights 3005 with driver, roll cage, two stock seats and heater. All other non essentials are gone. Car is all steel. SBS w th350.

 

Would like to put car on a diet.

 

Thanks

 

Bubba Fett

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Guest Anonymous

Bubba, my car is under 2300lb as is, with the original engine. It also has a/c, which is coming out. I figure that, along with the blower motor and various uneeded things under the dash, will drop about 30lb.

 

Race seats will drop a little more, not much. I will be going through the car and dropping all non-essentials, so a little more weight drop there (no idea how much). Also light wheels, etc.

 

A 302 with aluminum heads weighs less than the 240 engine. I'm not sure of the T-5 vs original tranny weight comparison, but a T-5 only weighs 71lb.

 

You have a heavier engine, and a much heavier tranny. Plus a roll cage, which is probably close to 100lb. Also, you're counting the driver, I'm not. smile.gif

 

 

 

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Michael Sen-Roy

Houston Performance

281-893-6080

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Guest John Adkins

The early Zs ('70-'71) are lighter than the 280Zs also, because the later Z have big bumpers, more crash reinforcements, etc. that the early Z dont...

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