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Discussion Starter · #1 ·
One of my biggest Annoyances of my car is how fast the motor is turning on the highway. I run 205/45/16 tires and at 80 mph on the gps the car is at 3500 rpm in fifth. It sucks! So I figure my two choices are to change the primary gears(if I can find a set), or swap up to a bigger tire and wheel combo. I would need to run at least 18's if not 19's. I kinda like the look of my super aero's so i am curious to see if anyone can do some math and tell me how much the taller gears will slow the engine speed down.

I am not going to put the huge sidewall tires back on nor will I ever slow down.;)
 

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I agree 1000% with you.

I have the exact same "problem". Its kinda a problem everyone has with these cars.

The only person on this board that I know has type 8s is ironjoe. But not sure if he's put them in or not.

No joke, I would, if I ever had a trans out of the car, would draw up the gears for type 8's and mill them out. Its one of those projects I'd wanna do in the far future though.
 

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If you ever find a source, I'm in for both my classics.
 

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In all honesty, I dont think it would be all that hard at all.

I know the number of teeth needed on both the input gear, and the output gear. If I just knew all the other info of the dimensions and such, make them, and either just take off links or add links to the drive chain.

How much harder could it be then that?
 

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In all honesty, I dont think it would be all that hard at all.

I know the number of teeth needed on both the input gear, and the output gear. If I just knew all the other info of the dimensions and such, make them, and either just take off links or add links to the drive chain.

How much harder could it be then that?
DrewP's brother is a machinist. My vert needs a trans anyway so I'm definitely in.
 

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there is just one issue, you would most defiantly have to make both gears tho. The stock primary gears the teeth are staggered so you couldn't machine them. you would have to have both machined out. there was a discussion on Saabrally.com about making the 4 row chains relating to the same issues. but iam sure someone could figure it out.
 

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I think DeLorean has some interesting setups in his transmissions - get him into this discussion, as I know he has rebuilt his SPG's transmission a few times and replaced it many more. I know there is some "rare" gears in his now which will probably get transfered into w/e trans goes in next (which may be this year since he now has more garage space to work in)
 

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The only person on this board that I know has type 8s is ironjoe. But not sure if he's put them in or not.
Yep I have Type 8 primaries installed. They've made a huge difference everywhere. 1st gear in these cars is terribly short, so having a taller 1st is very helpful. Also the obvious benefit of having lower revs at highway speeds is nice.

They were not cheap :oops: but totally worth it. Scour the UK forums and eBay UK, they turn up from time to time.
 

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there is just one issue, you would most defiantly have to make both gears tho. The stock primary gears the teeth are staggered so you couldn't machine them. you would have to have both machined out. there was a discussion on Saabrally.com about making the 4 row chains relating to the same issues. but iam sure someone could figure it out.
Are they 4 rows of gears/chains? I've never looked at one close enough to know. I've only seen pictures. Is the chain also staggered, or are 4 separate?

But in my head it doesn't seem terribly hard.
 

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Are they 4 rows of gears/chains? I've never looked at one close enough to know. I've only seen pictures. Is the chain also staggered, or are 4 separate?

But in my head it doesn't seem terribly hard.
stock ones are 3 row, upgraded rally ones are 4. The hard part is getting the gears out of your head, and into the real world. Gears are apparently exceedingly expensive/difficult to produce, thats been the main issue with getting a set made up at this point.

Paul
 

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I totally understand that. Thats why I need to look at it for about 10 minutes, then think about it for another 3 days and realize it probably wouldn't work out.

Being a ME major, with a machine shop at my (semi) disposal should help in the couple years to come.
 

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So, I had a discussion about this with my brother. Since he has taken a mechanical design class, he knew lots more about the processes of designing a gear set. He brought up alot of good design/strength determining factors that would need to be accounted for.

He said he'd be in to help.

If someone would be willing to send me a primary gear set, chain as well, we can get started drawing/designing a new gearset that has the 0.72 ratio. My brother has just this semester left of college, with only one real class, so hes got alot of time on his hands.....to design a new gear set.
 

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Discussion Starter · #15 · (Edited)
I don't have a set but could work on getting one. I could buy a spare trans and take a set out. Somebody has to have a set sitting around though. Do we know if the teeth are staggered for strength or to be smoother. Better yet we could try to get some drawings of the type 8's. I would put money on the fact somebody has them.
 

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ive heard rumors that an auto trans can donate gears that make for long legs... but i have no proof
You may be right. I converted my SE 'vert from auto to manual a couple of years ago. I've done NOTHING else for go-fast on that car and yet it really scoots. I suspect the primaries are taller. One of these days I'll have to crack into it and stare-and-compare it to the Commem.
 

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haha, I have an automatic, which is only a 3 speed!! So ya, I'm doing 60 MPH and 3500 RPM's!! Be glad you don't have an automatic. I really need to do a manual conversion!!
 

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ive heard rumors that an auto trans can donate gears that make for long legs... but i have no proof
Not quite sure, just thinking about the whole thing. The reason why people want the type 8 gears is that they offer a lower ratio from engine to trans.

The auto gears have a much higher ratio.

Thats the only reason why I'm thinking this may be false.
 
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