NOR-CAL General Chat.

[Cabriolet]

my car has mad under steer because I fly into corners to fast

gas in a corner, not brake. also make sure the front camber is higher than the rear. the only car that i had issues with was my mtech2 un-steering. hence the reason i had the frame straightened

[kronus]

Actually, the rear is typically much less rate at the wheel than the front with basically all setups ever done on an e30. The motion ratio is ~.65 making the rate at the wheel about 42% of the spring rate. In order to attain equal rates the rear would have to be more than double the front.

The rate does matter, but it's only one variable of many when it comes to handling and there is more than one way to skin a cat.

interesting

http://www.e30m3project.com/e30m3per.../eff_rate2.htm is a good read also

apparently the rear effective rate is 45% of the spring rate, but the front is 88%. That makes the effective spring rates on a 450/700 setup 396f and 315r, which makes sense given the weight distribution.

I'm curious what the actual effect on handling is. From playing with it a bunch at the track, it seems like as long as it's stiff enough to cut down on roll/pitch during weight transfer, and soft enough to not skip sideways, it's good.

[JinormusJ]

Ah, finally getting into the good stuff; I heard the trailing arm geometry causes a loss in at wheel spring rate, but I wasn't sure what the hard figures were on it. Calculating it out using that ratio then, 650# springs in the rear comes out to around 380# after the suspension ratio is applied, which means the fronts are still stiffer to combat the e30's oversteer

Kinda one of those "the more you know moments". Kinda cool knowing about it though

Now my only question is... If someone were to convert the rear into a trailing arm/strut hybrid and move the spring onto the strut (I've seen it done and there are some non-ghetto aftermarket companies that sell rear strut conversions), would I be able to run regular spring rates without having to calculate for the huge trailing-arm ratio?

[kronus]

Now my only question is... If someone were to convert the rear into a trailing arm/strut hybrid and move the spring onto the strut (I've seen it done and there are some non-ghetto aftermarket companies that sell rear strut conversions), would I be able to run regular spring rates without having to calculate for the huge trailing-arm ratio?

the rear ratio will go the other way a bit because the shock mount points are aft of the half shafts.

[Wh33lhop]

interesting

http://www.e30m3project.com/e30m3per.../eff_rate2.htm is a good read also

apparently the rear effective rate is 45% of the spring rate, but the front is 88%. That makes the effective spring rates on a 450/700 setup 396f and 315r, which makes sense given the weight distribution.

I'm curious what the actual effect on handling is. From playing with it a bunch at the track, it seems like as long as it's stiff enough to cut down on roll/pitch during weight transfer, and soft enough to not skip sideways, it's good.

The e30 doesn't really follow traditional handling rules I've noticed, and different things seem to work for different people. Some remove the rear sway, some run a big one. Higher front rate seems to improve front grip, likely due to less roll-related camber loss. I think it just has mediocre geometry and that means the contact patch sometimes does funky things under extreme conditions. I would obviously agree that there's a sweet spot but given the e30 truck's weight distribution (have you guys measured it?) I would take its behavior with a grain of salt if I were to extrapolate it out to a "regular" e30.

[Wh33lhop]

Now my only question is... If someone were to convert the rear into a trailing arm/strut hybrid and move the spring onto the strut (I've seen it done and there are some non-ghetto aftermarket companies that sell rear strut conversions), would I be able to run regular spring rates without having to calculate for the huge trailing-arm ratio?

Yes, but the motion ratio of the rear shock is more like 1.1:1. Also, this begs the question of... Why? You'd rather do that whole conversion than some simple math?

[Cabriolet]

Yes, but the motion ratio of the rear shock is more like 1.1:1. Also, this begs the question of... Why? You'd rather do that whole conversion than some simple math?

now if you only put this much effort into fixing your e30. i need another beater30 to roll with

[kronus]

The e30 doesn't really follow traditional handling rules I've noticed, and different things seem to work for different people. Some remove the rear sway, some run a big one. Higher front rate seems to improve front grip, likely due to less roll-related camber loss. I think it just has mediocre geometry and that means the contact patch sometimes does funky things under extreme conditions. I would obviously agree that there's a sweet spot but given the e30 truck's weight distribution (have you guys measured it?) I would take its behavior with a grain of salt if I were to extrapolate it out to a "regular" e30.

we've not corner weighed the truck, but given how much metal we've now lost off the front (no valence, accessories, headlights, foglights, electronics, cored hood) and how much we gained in the back with the fuel cell and cage, I think it's not far off.

my theory is that the wide variety in opinions about e30 suspension setups comes from the changes not actually causing much operational difference in actual handling and performance.

Top Gear ran a test a few seasons ago where they compared the stock and performancey (lower, stiffer, wider tires, bigger sways) versions of some new hot hatch, and the stock one ended up being faster.

[Thizzelle]

gas in a corner, not brake. Also make sure the front camber is higher than the rear. The only car that i had issues with was my mtech2 un-steering. Hence the reason i had the frame straightened

i know, i was saying i just enter to fast, brake late, so car tends to just go straight. FUCK BRAKES, RIGHT

[Wh33lhop]

now if you only put this much effort into fixing your e30. i need another beater30 to roll with

:( I need to swap subframes with our resident White Russian.

[Wh33lhop]

i know, i was saying i just enter to fast, brake late, so car tends to just go straight. FUCK BRAKES, RIGHT

You don't middle pedal so good.

[Cabriolet]

:( I need to swap subframes with our resident White Russian.

i need more info on this situation. and want me to loan a hand.

[Wh33lhop]

i need more info on this situation. and want me to loan a hand.

We are not quite sure of the situation yet. I think I might wind up taking my stock subframe over to press out the bushings and then just slap it in, but I still don't have my stock trailing arm bolts which is a problem. Don't have any spares, do you?

[Cabriolet]

We are not quite sure of the situation yet. I think I might wind up taking my stock subframe over to press out the bushings and then just slap it in, but I still don't have my stock trailing arm bolts which is a problem. Don't have any spares, do you?

i have a press, TAB tool and a compressor if u wanna do it when oliver does. i also have a full set of AKG mounts at home #SFDS308. new in box i could sell you as well

[blazinxpk]

HI GUYS


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