whats wrong wih the 2g suspension? (opinions)

[fjm9898]

i have been surfing around a bit and there are some great build threads and it brings up ideas in the suspension area

I know i already asked a suspension mod question

but i wanted to get opinions from you guys that have really put the time into your car and see what you think still needed a bit of work from the factory in the suspension area.

What kind of changes do you think they should of made to the suspension geometry? was something just not placed in the right area? i am asking these questions on a handling point of view. things that would fix quarks that you found that could be changed.

of course weight is always a complaint so let try and stay away from that. also lets try and keep adjustable parts out of question as a project car just wouldnt come with those kinds of things. so lets think of it in the sense of this was the sports car chassis by Mitsubishi and it was suppose to compete with the likes of skyline, supra, viper and so on with a similar price range to those higher end cars. remember, we are talking about suspension/handling not that they should of turbo'ed the hell out of it from the factory.

 

[TSI from Hell]

I'm pretty sure the 3Kgt was Mitsu's competitor to the Skyline, Supra etc...

As for suspension geometry amelioration, I think gixxerdrew could give you more insight.

 

[fjm9898]

i know the 3000gt was....... i am asking WHAT IF it didnt exist and the 2g was it and was competing with them in that price range. it was just an example statement.

 

[donniekak]

i know the 3000gt was....... i am asking WHAT IF it didnt exist and the 2g was it and was competing with them in that price range. it was just an example statement.

In that case, it would have had a larger engine, probably one of the 6g7x v6 engines. V engines are usually better off with 2 small turbos, so twin turbo. Of course it would have been awd, maybe eve all wheel steering. The interior would have been nicer, with more room. The body would have to be sexy and curvy. All this would have to cost around $50,000, in the late 90's.

So it looks like if there were no 3000gt vr4, and the eclipse was to compete, they would have to have called the 3000gt vr4, the eclipse.

To be blunt, there isn't anything you can keep from the 4 cylinder cheapish eclipse that will compete with the cars of the era that cost twice as much, without totally changing the car.

This is all from a factory standpoint. We all know a dsm can be modded to compete with lots of different cars.

 

[targett27]

Guys, the OP is asking about suspension, not any of the rest of the car. This is about what changes need to be made to the factory suspension to improve handling, we all know these cars can make the power to shine on the track, its the part where you turn thats the problem. Let's keep this thread on track because I want to hear the responses too!

 

[jtmcinder]

The main thing that I wish were different is the front bump-camber curve. The car has double-wishbone, so it could have been almost anything, but they didn't set it where I would have. Maybe they compromised so that the wrong-wheel drive could be the same as the AWD, but it should have been steeper.

The solution is to shorten the upper front arms and/or, if the rules you race under allow it, extend the upper eye-bolts (downwards). These will get it the bump-camber it needs.

Everything else is fine. The other things limiting the handling are the weight distribution and the fact that it's a pig. Those aren't the suspension's fault.

 

[arrowhead]

The main thing that I wish were different is the front bump-camber curve. The car has double-wishbone, so it could have been almost anything, but they didn't set it where I would have. Maybe they compromised so that the wrong-wheel drive could be the same as the AWD, but it should have been steeper.

The solution is to shorten the upper front arms and/or, if the rules you race under allow it, extend the upper eye-bolts (downwards). These will get it the bump-camber it needs.

Everything else is fine. The other things limiting the handling are the weight distribution and the fact that it's a pig. Those aren't the suspension's fault.

Could you be a little more explicit

 

[fjm9898]

thanks for those keeping on track and keeping their eye on suspension.
I do remember year and year ago one of those car and driver test drives of the car on the old Speed Vision and they did say the car handled quite well (of course back then) so it wouldnt surprise me if there are many complaints.

the gs/rs however they HATED the brakes, far to weak for the weight of the car.

 

[fjm9898]

anyone else?
i would love to hear more about your proposal jtmcinder

 

[jtmcinder]

If you search around, you'll see that I shortened the upper front arms by about 5/8" to get more static camber and a slightly better bump-camber curve. I was racing in Street Mod with that car and I read the rules as not allowing changes to the eye-bolts that hold the upper arms to the chassis, so I didn't change them. If the rules are more liberal than I thought, you'd just need a spacer so that they stuck further downwards to get even more static camber and a much, much better bump-camber curve. In fact, the curve might now be steep enough that you could delete some static camber for better straight-line braking.

The key here is keeping the tires at a slightly negative camber even when the car rolls. This is why bump-camber curves are so important: they specify how much camber you gain as the wheel is pushed up (into bump). Thus, bump-camber is how much camber you gain from suspension geometry as the car rolls in a corner. If you can get the curve up to being even vaguely close to 1:1, then the tire maintains the same camber, even when the body rolls.

- Jt

 

[importracr317]

If you search around, you'll see that I shortened the upper front arms by about 5/8" to get more static camber and a slightly better bump-camber curve. I was racing in Street Mod with that car and I read the rules as not allowing changes to the eye-bolts that hold the upper arms to the chassis, so I didn't change them. If the rules are more liberal than I thought, you'd just need a spacer so that they stuck further downwards to get even more static camber and a much, much better bump-camber curve. In fact, the curve might now be steep enough that you could delete some static camber for better straight-line braking.

The key here is keeping the tires at a slightly negative camber even when the car rolls. This is why bump-camber curves are so important: they specify how much camber you gain as the wheel is pushed up (into bump). Thus, bump-camber is how much camber you gain from suspension geometry as the car rolls in a corner. If you can get the curve up to being even vaguely close to 1:1, then the tire maintains the same camber, even when the body rolls.

- Jt

For your weekend warrior autox-er, could they acheive similar results with, say, RRE camber plates (pillowball upper mounts)? .... rather than going to the extreme of shortening the upper control arm. I don't think those plates get you more than an additional 2-4* positive or negative (which is still a lot), but it's better than nothing...

My contribution to the OP's question - I think the car is fairly balanced, save for a tendency to understeer at the limit. Better (ie, thicker) sway bars and some more progressive rate springs could've improved the design, but in my humble, nOOb opinion as far as suspension engineering goes, the 2G design isn't a terrible one.

 

[jtmcinder]

For your weekend warrior autox-er, could they acheive similar results with, say, RRE camber plates (pillowball upper mounts)?

Com'on. Camber plates on a 2G?

 

[fjm9898]

jtmcinder - was that mod to your arms in a thread some where? what kind of thread? i would love to see how you went about it.

So to sum up basically your saying that if the UCAs had added a bit more meat to the base of the eye bolts forcing the inner part of the arm to be lower this would save the bump camber issue.

Would this put any odd angel in the ball joint. i would think you would need to run more camber in the joint to match the change in angle

 

[TunaTalon]

At the risk of sounding like captain obvious the first thing to change on a stock DSM to make it corner better is performance tires with stiffer side walls and wheels to match with wider rims. The 2G DSM was compromised to be more like a touring car compared to the 1G compromised toward performance.

After trading in my 91 Talon with upgraded wheels and tires for a brand new 1998 Talon my wife got tired of me saying "I hate these tires" in every corner of Mo highway 47 on the way to Hermann wine country.

No one has mentioned sway bars yet. My RM racing bars seemed to make the Talon corner flatter and more neutral than the stock bars. The stock bars still leave a lot of under steer preferred by corporate lawyers.

 

[fjm9898]

I think the car is fairly balanced, save for a tendency to understeer at the limit. Better (ie, thicker) sway bars and some more progressive rate springs could've improved the design, but in my humble, nOOb opinion as far as suspension engineering goes, the 2G design isn't a terrible one.

i think sways and damper/spring rates are always a given. but there is a happy medium that has to be reached in a car designed to be a daily driver which is why those components arent as stiff as we would like in a track style car.

 

[jtmcinder]

The 2G DSM was compromised to be more like a touring car compared to the 1G compromised toward performance.

Wow. You don't often hear people refer to a switch from struts to double-wishbone as a "compromise," but this is the internet, so, if you're patient, you'll hear just about anything, I guess.

As to the mod to the upper A-arms: you weld small flat plates to the outsides of the "ears" on the inboard end and then drill new holes for the bolt about 5/8" inwards from the ends compared to the original holes. Then file off the ends of the ears so they don't gouge the inner fender. Et voila! Lots of static camber and slightly better bump-camber. Perfectly legal in Street Mod, too.

 

[fjm9898]

one i have the time ill dig deeper in search and see if i cant find your thread on it.

If you would be interested i am working with a shop to CNC a few parts and a fabricator for others, so.... if there is some level of interest in a CNCed part i could have an extra couple run off.
This is why i was asking about what mods really should be done that can help the current suspension as i wanted to possibly get a few bits made to fix any major down falls.
the holly grail of this being all new CNCed suspension components to save weight and add in those tweeks. probably wont go that far unless there is some major flaw we cant overcome with simple mods.

 

[jtmcinder]

Well, given that the threaded section on the front eye-bolts isn't really long enough to do the mod I suggested, maybe making some long eyes with sphericals would be cool. (I don't have a DSM any more and I run in Stock, so this would be for others.)

 

[arrowhead]

If you search around, you'll see that I shortened the upper front arms by about 5/8" to get more static camber and a slightly better bump-camber curve. I was racing in Street Mod with that car and I read the rules as not allowing changes to the eye-bolts that hold the upper arms to the chassis, so I didn't change them. If the rules are more liberal than I thought, you'd just need a spacer so that they stuck further downwards to get even more static camber and a much, much better bump-camber curve. In fact, the curve might now be steep enough that you could delete some static camber for better straight-line braking.

The key here is keeping the tires at a slightly negative camber even when the car rolls. This is why bump-camber curves are so important: they specify how much camber you gain as the wheel is pushed up (into bump). Thus, bump-camber is how much camber you gain from suspension geometry as the car rolls in a corner. If you can get the curve up to being even vaguely close to 1:1, then the tire maintains the same camber, even when the body rolls.

- Jt

I am a little confused, do you lose camber in bump or it remain static, or you gain camber.

 

[jtmcinder]

I was using a abbreviated way of saying it that might throw some people.

The suspension, both stock and after modification, gains camber as the wheel moves up. The question is whether, when the wheel's vertical movement is due to body roll, the outside wheel gains as much camber from the vertical movement as it is losing to the body roll.

The stock set-up doesn't gain anywhere near as much from the vertical movement as it is losing to body roll. This is the primary reason why increasing total roll resistance is so important to handling. You've got to stop the body from rolling and taking away your outside front camber.

After modification - as in: shorter upper arm and lower inboard upper pick-up - the bump-camber curve finally almost equals the loss of camber due to body roll. So now you can run less static camber and have better straight-ahead grip, especially braking, and still keep the outside front tire "happy" in a corner.

Again, I have a tendency to jump straight to the core issue: will the geometry of the suspension give you enough extra camber to cancel the loss due to body roll. But you should probably separate it into the two bits: the gain in camber due to vertical movement and the loss in camber due to body roll.

If you grok this, then you see why double-wishbone pwns struts for road racing: there is no way that a strut-based suspension will ever have the geometry required to gain as much camber in bump as you are losing to roll. Why Mitsu didn't engineer in a steeper bump-camber curve to the 2G front is beyond me. If I wanted to have to run 3* of static front camber, I'd have bought an Evo. Oh, wait ... I did.

 

[TunaTalon]

Wow. You don't often hear people refer to a switch from struts to double-wishbone as a "compromise," but this is the internet, so, if you're patient, you'll hear just about anything, I guess.

That’s known in the business as a straw man argument where something that is not said is disputed in a snarky attempt to discredit what was said. You see that on the internet thousands of times a day. My comment did not mention struts or any other component difference between the generations.

I owned 1G and 2G AWD Talons back to back, both purchased new and driven for a while on stock suspension, and stand by my actual statement that the 2G was compromised more toward touring than the 1G.

 

[cbarr0288]

Wow. You don't often hear people refer to a switch from struts to double-wishbone as a "compromise," but this is the internet, so, if you're patient, you'll hear just about anything, I guess.

..

As to the mod to the upper A-arms: you weld small flat plates to the outsides of the "ears" on the inboard end and then drill new holes for the bolt about 5/8" inwards from the ends compared to the original holes. Then file off the ends of the ears so they don't gouge the inner fender. Et voila! Lots of static camber and slightly better bump-camber. Perfectly legal in Street Mod, too.

So would this be a good thing to mod on a FWD? You mentioned it may have been engineered that way in the first place to make the FWD drive more like the AWD..

Bump camber is .. camber while in compression?

 

[jtmcinder]

Yep, bump-camber is the increase in camber under compression.

As to whether the lowered eye-bolts would be good for wrong-wheel ... er, front-wheel drive: absolutely! The biggest advantage of having a steeper bump-camber curve is that you can run less static camber. The need to run lots of static front camber to get these pigs to turn is what helps to kill a FWD launch, just as it hurts straight-line braking on both drivetrains.

 

[jtmcinder]

I owned 1G and 2G AWD Talons back to back, both purchased new and driven for a while on stock suspension, and stand by my actual statement that the 2G was compromised more toward touring than the 1G.

Okey-dokey. If you weren't referring to the switch from struts to double-wishbone when you said (now twice) that the 2G is a compromise between a 1G and a touring car, then what aspect of the suspension are you calling a compromise?

ps. kind of cool that you brought up "straw man" arguments, but I didn't actually intend to misrepresent your position, so it's a tad off-base; I saw you call the 2G suspension a compromise in comparison to the 1G and, given the topic of the thread, could see no option besides struts vs double-wishbone

 

[TunaTalon]

Okey-dokey. If you weren't referring to the switch from struts to double-wishbone when you said (now twice) that the 2G is a compromise between a 1G and a touring car, then what aspect of the suspension are you calling a compromise?

ps. kind of cool that you brought up "straw man" arguments, but I didn't actually intend to misrepresent your position, so it's a tad off-base; I saw you call the 2G suspension a compromise in comparison to the 1G and, given the topic of the thread, could see no option besides struts vs double-wishbone

Except for cars costing over a million dollars, all design aspects of all cars are compromises between competing goals. That's what makes engineering challenging. Go back and read my posts again. My position is that the compromises in the 2G are more in favor of touring, and the compromises in the 1G are more in favor of performance. Not that the 2G is a lesser (compromised) version of the 1G. In my opinion; the goals of the Mitsubishi engineers were more like the goals of the DSM community but design compromise directions were set by bean counters in the corporate management.

Clever engineers can design a car the way that corporate wants for showroom look and feel while leaving a car that can be easily modified to be more like they would want it. For example the double wishbone suspension you mention allows constant geometry with cornering forces but the corporate goal of a compliant ride resulted in narrow wheels and tires with floppy sidewalls. Tires are part of the suspension, when the sidewalls flex the geometry changes. Replacing the wheels and tires on a DSM takes better advantage of the suspension geometry.

Corporate lawyers want cars that under steer so the oblivious drivers are less likely to get in trouble. Changing the differential stiffness between the front and rear bars can change that to more like what the Mitsubishi car guys would like in their car.

Although not suspension, the same design compromises in the 2G resulted in a smaller turbo for less turbo lag. That's easily fixed. And when told to keep the HP down the car guys on the drawing board put a kink in the upper intercooler pipe and made the exhaust restrictive. That was easy to fix on my Talon.

As an old phart retired designer I have more respect for the engineers that created the 1991 Talon for a price that I could afford than for the designers of the McLaren F1 who when they needed a good reflective material simply choose gold.

Clever modifiers can take advantage of the original designers intent without a lot of expense. Or stubborn olde pharts can try to make the DSM into something it was never intended to be.