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I went out the the shop and picked up a little, I need to get the engine set together and set into the car to get weights but I just wasn't feeling it

Mentally I've decided I'm making new stub axles so I need to rear A-arm mounts. I need a rotation, the bottom is easy but up top its welded. The needs to move up/back, the rear down/back....or looking at it maybe just move the rear back and let the front come up a bit more so I don't need to raise the rear as much and maybe also use a bolt-on fork like the lower for the toe adjust.




Also I'm thinking about the rear roll high and how high it is compared to the front in the factory setup...F25, R103 is a huge difference and and cause the front outer corner to drip quite a bit. Also I remember really struggling with rear grip coming out of the corners, the height roll center doesn't help that either. So my new plan is leave the rear roll center right where it is down around 53mm, at least for now.

All of this math and engineering makes me think of all the racing and design that has gone on over the years. I know the computer helps a great deal but back in the day it was all hand drawn.
Thinking about Indy cars and F1 cars back in the 70 - 80. What a time for innovation. Even NASCAR and the parameters they had to work in with very little engineering. I know at one point in NASCAR they were moving front A-arm mounts weekly trying to find a sweet spot. Sway bars were huge and it was a lot of trial and error.
Seeing you sort the math and explain it is just fascinating. I can't imagine how much better my 74 Camaro could be with that kind of engineering applied.

_________________
Wade Williams
Master Ferrari Tech
Restoration Tech
Engine Machinist
Fabricator
Racecar Driver

Its most like our cars were made in another century..... The 308 was wrapping up design in 74-75? so 50 years ago and wasn't all that different from the 206/246 so 55-60 years old? Camaro about the same I guess. That is the whole restomod game...it looks so nice it should drive nice.

I spent about an hour piecing together the engine so its about ready to set in place to get weight. I was going to cut the motor mounts but for whatever reason I couldn't find my lathe chuck wrench and about the time it was pissing me off my son asked for some help and that was that for the night.

Just when I thought this thread couldn't get any more interesting. Thanks so much for sharing your thoughts and calcs about the suspension stuff.

Here's a question about requirements - do you think that there might be some value in retaining more roll and dive/squat for a street-driven car than you'd want in a dedicated race car? I think that Mazda attributes some of the "fun factor" of the Miata to those dynamics as they give the driver more feedback and increase the feeling of engagement (even if it's at the expense of outright performance).

Maybe it's a dumb question to ask someone who modified a 40 year old V12 to have Hayabusa valves and combustion chambers and make 900 hp.

Got an email for head gasket guy, they are in production!  I guess the issue was he wasn't sure how to do the sealant silk screening but he came up with something and gaskets are a go!



I've been playing around a little with and online program, Vsusp....the best I can tell the 308 suspension was always a hot mess.  Up front looks fine at rest



But it got super soft spring so hard brake and you have this



Then try to throw it into a corner and WFT



This basically says its going to want to plow like a mother because the rear roll center is up near 4" so basically all the corning load is on the outer front tire.....and I recall my first autoX with the car total stock there was no braking into the corner allowed.  

The car at its current ride height I have this



the same as stock with brakes, hot mess

Adjusting the bolt-on lower A-arm mounts frame mounts  up about 16mm (there is a kit available from super performance) gets it here



then brakes with about 60% anti-dive also baked into the lower A-arm mounts and roll controlled with stiffer springs and swat bar gets it here.



not great but okish.



In the rear it starts with a roll center up at 103mm, so when its lowered that actually makes the roll center much more rational



then when you brake (with anti-squat/lift) and corner nothing very bad happens



I want to play around a little more before I start cutting, particularly to see what can be done about the front roll center migration (moving right/left in corners) but I think its workable as is and I could very skip the rear anti squat and not be too bad.

I did get the engine kind of slapped together so I can set it in for a weight....hopefully this week.

You know....I'm not sure. Every manufacturer has specs they set to make the car feel the way the marketing team says it should feel so for sure they might be deciding roll and dive are good. I did read that no brake dive or accel squat or roll in corners confuses drivers....they have a hard time judging acceleration rates. without the movement. Personally I've never driven a car I thought was too stable, but I have drive cars I found too stiff/harsh so for me personally that is kind of where the lines get drawn.

On the 308 I thing a big part of what I'm not liking currently is related to the short wheel base and longer body. The body move quite a lot in pitch even though the axle numbers are not too bad. hopefully it will be better with a few minor changes.

Floors to sand before there is car time again

House project is stuck on color choice so thinking about the car's stub axles again.

So a 308 uses a 40mmID outer bearing and it looks like modial8 uses the same axles...they are well known to break with race use and I know for sure have also broken in autoX use.

A 348 axles uses a 45mm ID bearing and early cars the same CV joint as 308 so are a possible upgrade option.

328 and 3.2Mondial use a different axle from 308 and 348....anybody know what size the outer bearing size is? I don't ever recall hearing about broken 328 stub axles so I'm guessing 45mm but would love to know for sure if these are an upgraded part.

I found an OLD fchat thread from 2001 that was talking about 308 stub axles and included a 328 that lost a wheel at the track and blamed a poor design with inadequate radiusing and no heat treat, apparently fixed on the 348. I saw a couple 348 left side wheel carrier assemblies on ebay for around $1000-$1300, no rights to go with. It will likely be $2.5-3k if I go down this path. I'll likely end up making stub axles....

I know this suspension/stub axles is a little ping-pongy but I don’t want to fix the suspension and then change the wheel carriers and need to fix it again. The 348 stuff is a pretty pricey so kind of refocused on making stub axles and I have confused myself a bit. The 308 uses a 40mm (1.575”) ID bearing, the 328 and 348 a 45mm (1.772”) ID bearings but the 328s still have issues, maybe material, maybe design, probably both.

My plan was grab grab some US diff axles to use as blanks and start cutting knowing they rarely break and ASSUMING that was because they are big and heavy…wrong. The big bearing ford 9” and all the mopar use a 1.564” ID bearing, not quite 40mm. The small bearing 9” and a lot of GM stuff use 1.53”. There are some GM trucks with 1.618”…WTF? These things don’t break without REALLY trying and they are smaller?

Design wise the US axles all have a pretty decent radius between the wheel flange and bearing surface and that must be where the magic happens. For sure the US axles are heat treated and the 308 are not for whatever reason. The ferrari stubs have a nut torqued on to hold the CV flange, that is an extra force I guess.....but it feels like a slight design change will sort the issue. Just not certain the off the shelf US axles have enough metal where I need it, I think so? I probably need to pull mine apart and get some measurements so I can be strategic about what I order.