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.

 

[UofACATS]

shorten the upper front arms

What I planned on doing.

extend the upper eye-bolts (downwards).

What I now plan on doing. That's such a good idea

 

[cbarr0288]

What I now plan on doing. That's such a good idea

Take pictures and make a tech article if you do this!!

 

[importracr317]

Com'on. Camber plates on a 2G?

.... could've sworn I saw them on RRE's site. I know Tein has them.

Were you saying they don't exist? Or aren't necessary? ...

 

[TSiAWD666]

.... could've sworn I saw them on RRE's site. I know Tein has them.

Were you saying they don't exist? Or aren't necessary? ...

They don't exist because they are incompatible with the 2g's suspension design. RRE's site listing was a long-running goof that confused many a 2g owner.

 

[UofACATS]

Take pictures and make a tech article if you do this!!

Yes sir. I plan on shortening the upper arms 5/8" as jtmcinder has done, plus a few experimental lengths to see what happens. I'll also experiment with dropping the eyebolts different lengths.

I have a 95 Talon AWD shell I'm using as my test piece. I can pull the front suspension and rotate the wheel through the entire ROM. But that's enough talk from me.

 

[jtmcinder]

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.

I understood what you meant; I just don't agree.

"Performance" is too general a term. What kind of performance? If we're talking about trying to turn on smooth tarmac, then, I'm sorry, but struts will not equal double-wishbone. The only downsides of double-wishbone are more unsprung mass and less suspension travel. Thus, the only time that struts beat double-wishbone in terms of performance is racing on bumpy roads ... aka rallying.

In other words, if the car is meant for racing on tarmac, anything other than double-wishbone is the compromise. Why do so many cars have struts when they are never meant to go off-road? Because it's much cheaper and simpler, plus won't have problems on speed humps or other unexpected bumps in the road.

On the other hand, a car that is intended to spend time on tarmac and could have had double-wishbone but has struts, instead, such as an Evo or a 1G, is a compromise. It's not quite as good as it could be on tarmac, because of the geometry of struts, but it has tons more travel and has less unsprung mass than a car with double-wishbone. Thus, it's a compromise.

Again, I know what you are saying. I just think that you have it exactly backwards.

If you disagree, then please tell me what should be different about a 2G if it is meant to race on tarmac. What, exactly, is this compromise you see in the design of the 2G?

 

[jtmcinder]

you need to make sure you stiffen the rear a good amount the eclipse has good steering but it has a very heavy back end and whenever you take a turn fast the heavy back end shifts and slides out first is to get a rear strut tower bar next get stiffer and lower springs after that make sure the camber and caster of your wheels are correct because if not it will jill the whole point of you doing anything after that go weight reduction like if you have a massive gst spoiler on the back that weighs about 50 pounds and then if you go carbon fiber on hood and trunk then you will lose at least another 100 pounds and after that remove the spare tire and put a can of fix a flat in there thats what audio shops do when they use the spare tire well for extra air space and after all that is said and done make sure you have good tires and a good front strut bar and then check the sway bars and all bushings and ball joints if everything is good then your handling should be comparable to at least a dc integra gsr hatchback

i think

I'm sorry to say that you think incorrectly.

These car understeer.

Strut-tower bars are nearly worthless until you have very high spring-rates. The chassis of a 2G has terrible torsional stiffness, but the problem is in the area around the driver, not between the wheels.

150# from the spoiler, hood, and trunk?

Most of the rest is babble.

 

[Calan]

you need to make sure you stiffen the rear a good amount the eclipse has good steering but it has a very heavy back end and whenever you take a turn fast the heavy back end shifts and slides out first

I wish.

As Jtoby said, these cars suffer from understeer; not oversteer.

From what I've noticed... on an AWD car, attempting to make the back end come around with sway bars or heavier springs doesn't accomplish a whole lot. The center diff will normally see this as a loss of traction in the rear and try to compensate for it. If anything it tends to just make the understeer less predictable. At least it did on my car.

I'm pretty happy with the balance of my 1G now, but it's taken a lot of trial and error (and adapting to the way it handles) to get there.

 

[jtmcinder]

Agreed. When you apply standard thinking to 2G AWDs, you often get a car that snap-spins and is just about uncatchable. Have I obnoxiously mentioned how much I love the Evo X lately? tee hee

 

[Calan]

Have I obnoxiously mentioned how much I love the Evo X lately?

Well no... but you have obnoxiously mentioned a few other things.

 

[jtmcinder]

For those keeping score at home, that would be Craig 1, Toby 0.

 

[fjm9898]

very good read fellas and i must say as far as arguments go very civil compared to some forums i have been on

once i get the car on the road and start seeing the issues for myself first had i will be sure to start a new thread in the suspension area and see what we can worked up. maybe some CNC'ed parts or what ever. for sure i will be trying the eye bolt change. To bad we cant get the ball joins on the SPC arms to work properly
speaking of that... is there an off the shelf ball joint we could use that is proven with the SPC arms are modified to fit them? or would be need a whole new arm produced?

 

[jtmcinder]

I wouldn't be so sad about the SPC adjustable upper-arm ball-joints not being available or not being reliable. That was never the right approach, IMO, because it cost you too much travel. The answer was always, again, to be humble, my method of just shortening the arms, themselves.

Plus, it's cheaper.

ps. agreed about the thread; usually when I get going, I ruin the thread with my testosterone poisoning; it helps that while Tuna and I often disagree, I, at least, have respect

 

[fjm9898]

ya i just liked the SPC arms for being lighter then stock and having the adjust-ability.
So that is why i asked if there was an aftermarket joint out there that was proven to hold together that we could design a new lightweight arm with the shortening mod in there as well as the adjust-ability

 

[TunaTalon]

I understood what you meant; I just don't agree.
What, exactly, is this compromise you see in the design of the 2G?

Of course the multi-link suspension has better geometry that struts. Everyone who gets past newbie status knows that. Your very public assertion that I considered the multi-link a downgrade from the 1G struts was first class flame baiting. (testosterone poisoning?)

I can understand how you might not agree that the 2G is more like a touring car than the 1G if you limit the comparison to suspension, and then stay strictly inside the box of geometry. However; there is more to the driving experience than Geometry. When I traded my 1991 Talon for the 1998 I expected improved handling with the change to a multi-link, but was disappointed. The new Talon was smoother than the old 1991 on straight and level but sucked on tight rough corners.

The clever Mitsubishi engineers allowed me to change from the car that the Mitsubishi front office wanted to the car that I wanted with only new shocks, sway bars, tower braces, tires, and wheels.

And if you can get out of the suspension box and look at overall the car there were other changes in the direction of touring and away from boy racer:

Smaller turbo
Higher velocity intake manifold
Torque curve moved down

There are probably more but this is a suspension thread. As I said in my first post in this thread the first and cheapest way to improve the handling of a stock 2G is to upgrade the tires and wheels. All else here is just in response to snark.

ps. agreed about the thread; usually when I get going, I ruin the thread with my testosterone poisoning; it helps that while Tuna and I often disagree, I, at least, have respect

Ok, ok enough already with the testosterone poisoning. How about something useful?

I have always thought of my Talon as having a multi-link suspension which was different from the olde Honda double wishbone. In your prior post you called the 2G geometry a double wishbone. Hah, I said, I've got him now and checked one of my 2G talon shiny brochures. They called it a double-wishbone/multi-link.

What gives? I still think that there is a difference between the geometry on my Talon and what I remember about Honda advertising back in the day.

 

[ed1380]

What would you consider high spring rates?

I'm sorry to say that you think incorrectly.

These car understeer.

Strut-tower bars are nearly worthless until you have very high spring-rates. The chassis of a 2G has terrible torsional stiffness, but the problem is in the area around the driver, not between the wheels.

150# from the spoiler, hood, and trunk?

Most of the rest is babble.

 

[jtmcinder]

700 or more in the front; 375 or more in the rear.

 

[Ludachris]

The two things I would change about the 2g suspension (outside of what Jtoby mentioned) isn't actually part of the suspension - it has to do with the chassis. The chassis itself is more flexible than the 1g, so you have to put a lot of effort into stiffening right out of the gate. The second would be the clearance, or lack thereof, for significantly wider wheels and tires.

 

[Zefal151]

700 or more in the front; 375 or more in the rear.

Is there a conversion chart I could use? I have 13k front and 10k rear

 

[TunaTalon]

The two things I would change about the 2g suspension (outside of what Jtoby mentioned) isn't actually part of the suspension - it has to do with the chassis. The chassis itself is more flexible than the 1g, so you have to put a lot of effort into stiffening right out of the gate. The second would be the clearance, or lack thereof, for significantly wider wheels and tires.

Resonant frequency of the chassis is a good proxy for chassis stiffness. The C5 Corvette has a resonant frequency of about 21 Hz for context.

I accidentally found a way to calculate chassis stiffness in Hz when a tire went out of balance.

My Talon had a vibration that peaked when the frequency of the wheels rotation matched the chassis resonant frequency at about 80 MPH. It was a few years ago but I remember it being about 18 or 19 Hz

The calculation starts with the tire revolutions/mile; for my car 836 revs/mile.

Revs/mile * mph = cycles/hour
cycles/hour / 60 = cycles/min
cycles/min /60 = cycles sec or Hz.

In my case 836 revs/mile * 80miles/hr = 66880 cycles/hr
66880/ 60/60 = 18.5 Hz

If you don't mind adding a wheel weight to one of the front tires this technique will allow an obective measurement of any modification intended to stiffen the chassis.

 

[knochgoon24]

Is there a conversion chart I could use? I have 13k front and 10k rear

You're converting from lb/in to kg/mm.

1 lb/in = 0.0178579673 kg/mm.

700 lb/in = 12.5 kg/mm
375 lb/in = 6.7 kg/mm


For comparison, I'm running 600F/350R. I just got some RM Racing sway bars. This weekend, there's a 2 day autox event at an airport nearby. I installed just the rear one for now. I might swap the front in Saturday afternoon before the second day Sunday to see if I like the additional front. We'll see.

 

[TunaTalon]

I just got some RM Racing sway bars. This weekend, there's a 2 day autox event at an airport nearby. I installed just the rear one for now. I might swap the front in Saturday afternoon before the second day Sunday to see if I like the additional front. We'll see.

Please report back here (or PM a link to me if on another thread) on your results of the RM racing sway bars on your 2G AWD Talon.

On Sept 27 I was forced off of I44 by an oblivious driver and got both left wheels in the dirt well below the pavement. While clawing back to the pavement the Talon was high centered at an angle to the road at about 65 to 70 MPH. The impact and the angle caused the car to skid and I was only able to catch the first slide before a snap 180 where the engine died going backwards down the highway. The skidding reduced my speed enough for a gentle roll into an embankment muffler first. RIP Thermal Research cat back.

I know my RM racing sway bars reduce the native under steer but wow, that was a fast spin. For what it's worth I was at lift throttle until the engine died. Then I was a spectator.

When you get both sway bars on and end up at lift throttle with all four wheels sliding, well don't take notes right then, but let me know later if your Talon does a snap spin.

 

[jtmcinder]

I'm not sure if calculating something like the resonant frequency of the chassis gets at the real problem with the 2G. The problem is the lack of torsional stiffness between the axles (as anyone with a 2G with a sunroof is probably aware). The reason that this is a problem is that, for example, the standard trick of increasing rear roll stiffness so that the outside rear wheel keeps the inside front on the ground doesn't work anywhere near as well. Instead of moving grip forward, you end up just losing rear grip and now the car snap-spins.

The torsional stiffness is so bad that I actually calculate everything for the front and rear of the car separately and then, when the two values of, for example, roll angle differ, I pretty much split the difference. I know that that's ridiculous, but it seemed to work better.

Since Chris has opened the door to ragging on anything that hurts 2G handling, let me add that the weight distribution is awful. Given that many makers had already figured out how to do mid-engine-rear AWD, I wish that the DSM (and the Evo, for that matter), was mid-engine-front AWD, instead of front-engine AWD.

 

[TunaTalon]

I'm not sure if calculating something like the resonant frequency of the chassis gets at the real problem with the 2G. The problem is the lack of torsional stiffness between the axles (as anyone with a 2G with a sunroof is probably aware).

With one front wheel out of balance the resonant frequency of the chassis will increase as the torsional stiffness increases. The imbalance forces will work to "twist" the chassis and the more the chassis resists twisting, the higher the resonant frequency. It won't fix anything but could help diagnose any attempts to stiffen the car.

The reason that this is a problem is that, for example, the standard trick of increasing rear roll stiffness so that the outside rear wheel keeps the inside front on the ground doesn't work anywhere near as well. Instead of moving grip forward, you end up just losing rear grip and now the car snap-spins.

That's an interesting comment that could apply to my recent off road excursion. Please see my post 48. I have enjoyed the DD experience of those sway bars for years but that event has caused me to re-consider.

 

[jtmcinder]

My criticism of the resonant-frequency approach is that it is sensitive to both torsional stiffness and the damping. What we want is just the stiffness. A much better approach, therefore, is the old one-jack-stand-shorter-than-the-others method. That will get you exactly the needed information.

Unless you have an Evo, of course, since you only need three jackstands when the car is a rock, eh, Craig?