New name and and new engine for Mina: an e30 for the GF

[Andy.B]

Hell to the yes.

Whenever I am about to make a particularly questionable decision regarding a worryingly cheap diy solution, I just ask myself, "What would Ether-D do?"

[jt223539]

Any pictures of what you are doing on the rear for adjusters? I am looking for a affordable way to get adjusters in the rear of my e30, and you may have the solution I am looking for.

[Mr. Tasty]

Spring rates are an intensive property, why would halving a 10 inch 375lb/in spring double the spring rates? With the lb/inch rate, you are goings to have two, 375 lb/inch springs now.

[efficient]

oh my that strut. must suck living in ny and owning a rusty car.

[Andy.B]

Spring rates are an intensive property, why would halving a 10 inch 375lb/in spring double the spring rates? With the lb/inch rate, you are goings to have two, 375 lb/inch springs now.

http://www.eatondetroitspring.com/cuttingcoilspringscalculations/

[Mr. Tasty]

http://www.eatondetroitspring.com/cuttingcoilspringscalculations/

Interesting concept, I would love to see some "real world" testing with loads to test it.

[Ether-D]

Whenever I am about to make a particularly questionable decision regarding a worryingly cheap diy solution, I just ask myself, "What would Ether-D do?"

I just lolled so hard. Thank you! I may have to sig that shit. Yep…

With money, being a badass is easy. With no money, being a badass takes skills bitches! (and a certain willingness to try just about anything)

[Andy.B]

Think of a diving board. The farther out you walk, the bouncier it gets. When you get to the end, it will be drooping towards the water just by standing on it. It's because the spring rate of the board acting against your weight is lower the farther out you go from the fixed end. That is why driving boards usually have rollers underneath to roll towards or away from the middle. It allows the diver to adjust the diving board to their desired spring rate.

A coil spring works the same as a diving board. It's just wound into a coil instead of being straight. If you took that same piece of coil spring and straightened out out you would have a piece of metal with the same spring rate. By cutting it in half, there is less metal to flex, raising its spring rate.

You don't need real world testing. It is math. I know it can seem counter intuitive, but that's how it works.

[Mr. Tasty]

Think of a diving board. The farther out you walk, the bouncier it gets. When you get to the end, it will be drooping towards the water just by standing on it. It's because the spring rate of the board acting against your weight is lower the farther out you go from the fixed end. That is why driving boards usually have rollers underneath to roll towards or away from the middle. It allows the diver to adjust the diving board to their desired spring rate.

A coil spring works the same as a diving board. It's just wound into a coil instead of being straight. If you took that same piece of coil spring and straightened out out you would have a piece of metal with the same spring rate. By cutting it in half, there is less metal to flex, raising its spring rate.

You don't need real world testing. It is math. I know it can seem counter intuitive, but that's how it works.

No moment of inertia involved in a spring, but I can kind of understand your points. You are saying it has nothing to do with the material properties that would normally provide spring rates, but revolves around forces sitting on top of of spring coils?

[Andy.B]

No moment of inertia involved in a spring, but I can kind of understand your points. You are saying it has nothing to do with the material properties that would normally provide spring rates, but revolves around forces sitting on top of of spring coils?

I'm not saying that. The material has its own properties that effect spring rate, but an inch of material X does not have the same flexibility as 2 inches of material X just because they are made of the same material.

I think you are over thinking this.

[Mr. Tasty]

I'm not saying that. The material has its own properties that effect spring rate, but an inch of material X does not have the same flexibility as 2 inches of material X just because they are made of the same material.

I think you are over thinking this.

I figured flexibility would be the same for the coils after the dead coil, because of the similar vertical compressive forces. That's why I said I wanted to see actual force graphs, not that I doubted you. I understand Hooke's Law but I didn't think that would apply here.

[Andy.B]

e28 3.25 diff is in, and rear coils are in:



I think I am going to cut up a hockey puck to make a better centering ring for the spring, but as it sits, the bump stop will keep it from falling out. I think that with shorter shocks (probably camaro rears), it will be captured nice and snug.

The e28 rear/e30 auto front driveshaft combo will fit. CSB mount is about 1.5 inches too far forward, but I may be able to just weld a bolt in place and bolt it in, as it still sits on the 'shoulder' type mount area for the CSB.

All that is left is to shorten the shift carrier and selector rod, bolt in the drive shaft, and weld the m30 downpipes to the e30 exhaust. Hopefully we will have it driving in the next couple of weeks.

[Andy.B]

I test fit the g265rear/4hp22 front, and while the length is acceptable, there are two problems. First one is the previously mentioned issue of the CSB not lining up. The second issue is that the 4hp22 from an m20 car has a small guibo, while the g265 is a large guibo.

From another post, it looks like an m10/auto driveshaft is in between the m20/auto driveshaft and the m20/manual driveshaft in length, which should make it a usable fit behind the g265. Fingers cross while I go down the rabbit hole of research.

If anybody knows the length of an m10/auto driveshaft, I would love to know.

Also, does the g260 transmission output flange swap with the g265 output flange?

[Andy.B]

When I converted my car to coil overs, I paid a machine shop to machine down the strut inserts, and to cut and section the strut housings. I payed $125 total, iirc. Certainly not a bad deal, by any means, but this time I wanted to see if I could do it cheaper.

How to modify mr2 shocks for e30 fitment, the cheap way:


I put some grease on the strut insert, clamped down the housing, and slid the insert into the housing. Then I tightened the nut down on the shaft, held a file against the section that needs to be filed down, and spun with an impact wrench. It took about 3 or 4 minutes per strut, and saved me $25 at the machine shop.



Next up was to section the strut housing 2 inches. I bought a metal chop saw from Home depot for $179. Sure that costs more than the machine work work have, but now I have a chop saw I can use for all sorts of things. When it came time to piece an exhaust together out of the stock e30 and e28 exhausts, it paid for itself in time saved with the ability to make perfectly straight and square cuts through exhaust pipe.

A quick cut with the chop saw, and a few minutes welding, and I had 2" shortened strut! A straight section of e30 exhaust pipe works perfectly to line up the top and bottom parts of the housing for welding, as it is a snug fit into the housing.

All assembled:

[Andy.B]

The car is now waiting in my driveway until I can get a small guibo output flange for the transmission. I've been hunting around, but have had no luck so far.

In order to get the car moving under its own power, I need one of these guys:

The small flange guibo has holes that are 2.6" apart, while the large flange is 3.12".
The part number for the small flange is 23211228298.
It looks like this:


If anybody has one they are willing to sell, send me a pm!