whats needed for ultimate handling?

[jdsoza]

Finally I'M picking up my 2G shell tomorrow, and I am starting on the suspension right away. the most modified DSM I have seen for handling goes to Andrew Brilliant, and I am going to be building a time attack car, but AWD not FWD. So far I want all the bushings to be replaced with poly bushings that can be. next im sending the subframe to be modified by robispec. Im going to run basic coilovers for now, but later double adjustables will take there place. I want to know what you guys are using to make handling great. Im wanting my car to handle like an EVO and i know its going to be a long hard road.

 

[TSiAWD666]

You're likely going to have to get a bit creative as the off-the shelf stuff now available will only get you maybe -1 to -1.5 degrees camber in the front (like Ingalls and SPC a-arm anchors or eccentric bushings). Perhaps some custom made upper a-arms in tandem with SPC's ball joints (are those still available standalone?) would do the trick. I remember someone slotted the stock upper a-arms once to get some more camber but I can't recall who or how that really turned out.

Of course you could try to bribe someone for their SPC replacement A-arms but then you'll have to deal with their balljoint issues and there are no spares for those available from the manufacturer.

You might want to try the fender braces that Greengoblin produces. I have them on my car but have yet to drive on them as the car's at a shop. There might be one or two Eclipse owners out there with similar bracing but I haven't found any anecdotes from them on how they perform. Robert told me when he was troubleshooting some odd push on a track Evo that adding the Nagisa braces (which are the same concept and very similiar design) completely eliminated his pushing issues and allowed the car to track as they had expected it to track, and suspected the frame out to the strut tower is just flimsy and deforms when you add in really sticky tires and stiffer suspension. He suspected the Eclipse when looking at it would have the same issues. We'll see how they work in a few months though I'm throwing a lot of variables into my testing so I probably won't have any conclusive results on this particular mod then. Here's a pic of what I'm talking about:
<img src="http://www.dsmtuners.com/gallery/files/2/0/6/0/0/fender_brace_installed.jpg" alt="2g Fender Brace Installed" />

Stitching up the frame for more rigidity may help, but the only person I know who's done that is Greengoblin and his car's not yet ready for prime time either, so no word on its effects. Maybe he'll pop into this thread and comment.

You'll want to consider what anti-sway bars to use. Robert strongly recommended to me that I try a stock in the front and a thicker RRE one in the rear. I currently have the RRE in both front and rear but picked up a stock one to try out next time I have the transfer case down. I tried just the stock one with RRE rear in the past on my tokicos but thought it was bad because of the body roll... only much later to learn that was more from me screwing up my suspension geometry by lowering the car and not compensating. Now with the modded subframe I need to re-visit that idea and see what it's like.

There are spherical upper mounts to look at. Depending on what shocks you choose you'll want to look for those. If going with KW V3 RRE sells the upper mounts.

Oh, you may want to look into stronger and possibly lighter wheels to avoid deformation from the forces of bigger and stickier tires. I'm going to try cheaper Enkei RPF1s but I can't say it was a good choice (though they are very light). I know Andrew went with CCW rims which are probably much stiffer but I can't get any data from CCW to prove that (they're forged as opposed to the Cast/MAT technology that Enkei uses in the RPF1s). They are very expensive wheels though (over triple the cost of the RPF1s), so I opted for a cheaper set to do my initial exploration and keep within my budget while I get this money pit moving again

Can't think of anything else beyond your stated plans as they match the path I've taken. I too am following in Andrew's footsteps. I also can't comment on the efficacy of all that I have as my personal experience with much of it is very limited (no track time on any of it yet), and will be until later this year when my car is final on track again. I can say with some confidence that the KW V3 coilovers modified from Robispec really are pretty damned good as I got about a couple weeks on those on the street, but they are the highest end coilovers I've used (had crappy tokico illuminia with some high rate springs on gc coilovers). These are the ones (albeit with different rates) that Andrew is using.

You'll love the subframe mod because it reeeeeeeeally keeps the car so much flatter... it's like a totally different car.

 

[jdsoza]

Wow thanks for the info. I do have a fabricator who's building me some a-arms. I forgot to mention the first mod I'm doing is stitch-welding the chassis. I'm also putting some bracing in the front of the wheels, having custom wheel tubs done on the front and then braced all the way across. My fabricator is building arms for camber adjustment that are identical to the Ikea formula arms used for the SC300. Sc300 ball joints cannot be replaced alone, they need new arms and hence why we're using billet cnc cut arms vs tubular arms. Its costing me a pretty penny ($800). So when I have some of those finished ill post pics.

 

[jtmcinder]

I've never seen that "fender brace" before, but it's brilliant. Pull that on a non-sunroof 2G and you might actually be able to use a rear swaybar to keep the inside front down. Nice.

 

[cantgo2fast]

Dangit! I totally thought this was a noob question and was going to be smartass but if your doing the subframe then youve done your homework.

Have you decided on tires? DOT slicks, Race tires, street tires?

Car is only as good as its driver! I would recommend getting to a driving school, if you havent already. Then tagging along anywhere and everywhere you can. Maybe find someone you could co-drive with at autocrosses or ride along with on track days. Seat time is as valuable as any part you can buy.

 

[Bud92gsx]

That fender brace is sweet. I bet it does help with stiffening up the chassis.

 

[bmoha7321]

Going to have to pickup a set of them from Kevin!
This is an ambitious build plan. There's a lot of money involved. My budget doesn't allow for it or I guess in reality, if I stuck to it, goes slowly.
I went for a set of black_gst's cnc machined aluminum front subframe bushings. I also did some additional stitch welding to the front subframe. Solid rear differential bushings would be an excellent upgrade as well. Along with the same for the rear subframe.
I didn't see brakes mentioned in your build plan. Not something to be overlooked.

 

[jdsoza]

Dangit! I totally thought this was a noob question and was going to be smartass but if your doing the subframe then youve done your homework.

Have you decided on tires? DOT slicks, Race tires, street tires?

Car is only as good as its driver! I would recommend getting to a driving school, if you havent already. Then tagging along anywhere and everywhere you can. Maybe find someone you could co-drive with at autocrosses or ride along with on track days. Seat time is as valuable as any part you can buy.

I bet a lot of people thought it was going to be a noob question, i stated it in a noob kind of way. We don't have a "true" double wishbone so its harder to control suspension flex and we must treat all areas of movement independently. As heavy as these cars are, the chassis still seems flimsy, and the suspension seems flimsy too. I'm totally doing the brake upgrades too, just focusing on making it grip better first. a stock car with big 13-14-inch rotors seems pointless to me. since i have a shell to start with, im also focusing on cutting out weight. weight can majorly affect how a car corners. Has anybody seen the Super Autobacs S2000 run? at just over 1800LBS and merely 300HP this car can trap tsukuba in under a minute. Granted most S2000's will walk an eclipse in the park on a track, it still proves a principal. I've been looking for a thread for total weight reduction, anybody care to give me a link?

 

[ACM]

We have "better than" double wishbone - in the front at least. The big compromise in a 2G is the large, soft rubber bushings in the control arms. Replace those with spherical bearings and I suspect suspension control will be very good.

At least our roll centres are well coordinated, which is more than can be said for anything with struts at one end and <something else> at the other. No offence intended to 1Gs

2Gs with sunroofs suffer horrible torsional rigidity - once the spring rates firm up the shell provides half the wheel travel. Jack a sunroofed 2G up and put one rear jack stand one notch lower than the other; now drop the car down - notice how the car sits firmly on both jack stands ? Not good...Repeat with a non-sunroof 2G and yes, the low jack stand corner will sag a little, but only just visibly. I wouldn't recommend sticking your hand in the gap, but if you did you'd feel very little sag at all.

And talking about jacking the car up - when you jack the front up, watch the fire wall - the front flex is scary. Great idea on those fender braces Kevin ! Shame my rules won't let me run them Now tie those into the front of your roll cage and...

The first step to good suspension is making sure the suspension is the only system managing wheel travel. On a 2G that means an extensive roll cage or extensive strengthening.

I don't really notice any body flex running street tyres on my 95.5 non-sunroof car - my 98 sunroofed was another matter entirely. It goes without saying that the race car is non-sunroof.

 

[jtmcinder]

I agree with both previous post. Yes, the front suspension on a 2G is a bit weird with the lower "A-arm" split into two pieces and causing all sorts of forward-backwards movements in bump/rebound, but there's a good reason for this. Keep in mind that it's all about bump travel; when you run out of bump travel, handling becomes non-existent. So the question is how does the funky lower half of the front suspension relate to bump travel.

Assuming that the car has not been over-lowered, the compression arm (which is the back half of the lower "A-arm" - i.e., the one that goes from the knuckle to near the feet of the driver and passenger) angles up from knuckle to chassis. This creates "anti-dive/anti-lift" geometry. It's like the effect of a nice, high roll center for turning, which prevents body roll. Anti-dive geometry prevents nose-dive under braking. This is really important because if you didn't do something to prevent nose-dive under braking, then the combination of a bump in the road and hard braking could cause one or both front wheels to run out of travel, lose grip, and bye-bye ... straight off the road.

Now, if you have over-lowered your 2G (and not done something to fix the anti-dive geometry), then you lose the positive of having a funky, two-piece lower "A-arm" and have only the negatives. A fancy, hand-made lower front subframe might be able to get the roll center back up, but I've never seen anyone try to fix the anti-dive, probably because I don't see how you could raise the inboard pick-up point and no-one seems to have tried the long-stalk outer ball-joint approach (which is how this is dealt with on Evo Xs). Maybe some more thought should go into this. The Chapman method of just upping the front spring rates until the suspension doesn't move kind of defeats the whole point of having some kind of double wishbone in the first place.

 

[snowborder714]

Not to take this too far off topic, but do you think to fix the anti-dive a whole new arm would need to be designed so we could use some aftermarket ball joint (pending if we could even find one that would fit the knuckle, as I know this has been an issue in the past)? Or would we want to look at possibly replacing the current one?

 

[TSiAWD666]

Wow thanks for the info. I do have a fabricator who's building me some a-arms. I forgot to mention the first mod I'm doing is stitch-welding the chassis. I'm also putting some bracing in the front of the wheels, having custom wheel tubs done on the front and then braced all the way across. My fabricator is building arms for camber adjustment that are identical to the Ikea formula arms used for the SC300. Sc300 ball joints cannot be replaced alone, they need new arms and hence why we're using billet cnc cut arms vs tubular arms. Its costing me a pretty penny ($800). So when I have some of those finished ill post pics.

Any chance your fabricator would be interested in producing more sets? I'd be interested in learning more about them (we can take this discussion off-line). If nothing else I'm sure others here would love to see the results. Will they include caster adjustment as well?

 

[jtmcinder]

@Brian

There are only two options, really, just as there are only two options to fixing the roll center when you lower too much. You must lower the ball-joint at the knuckle end (using, e.g., an extended-stalk ball-joint like what WhiteLine makes for Evos) or you must raise the pick-up point on the chassis. Raising the pick-up point for the lateral arm can be done to fix the roll center; that's one of the best reasons to get a custom front subframe. But I really don't see how you can raise the pick-up point for the compression arm anywhere near as easily (not that getting a custom front subframe is "easy"). Moving the inboard pick-up for the compression arm might well require cutting out a section of the floor of the car.

Sorry. Third option: completely custom knuckle with lowered eyes for both the lateral-arm and the compression-arm ball-joint. And this one is even legal for SM.

edit: personally, if I were going to go through the hassle of getting a whole new front subframe, I'd seriously consider just going with a true lower A-arm and saying "screw it" WRT traditional anti-dive. Yes, it would take some work, since the OE subframe doesn't seem ready to take anything close to all the force, but I hate what the compression arm does to everything besides anti-dive, so if I can't get the one good thing, I want the thing gone. It's freaking heavy, to boot.

 

[TSiAWD666]

@Brian

There are only two options, really, just as there are only two options to fixing the roll center when you lower too much. You must lower the ball-joint at the knuckle end (using, e.g., an extended-stalk ball-joint like what WhiteLine makes for Evos)...

I asked Robert of Robispec why not use that instead of the modded subframe and he only said it wasn't possible on the Eclipse and it wouldn't work despite working terrifically on Evo 7-9s. Said it would be obvious if I looked at it but when I did it sadly wasn't I didn't ask him to elaborate as we really busy doing the subframe and coilover install together while he was doing his typical 5000 customer calls amidst our work

Not sure what that's worth but figured I'd offer that up.

 

[ACM]

If I was going to the trouble of dropping the outer arms down I would do that with a camber/caster/track mod at the same time.

Take a flat plate, 2"x4" or so, drill two pairs of holes, one pair the same distance apart as the BJ holes in the upright, the other pair "slightly further apart". Bolt one side of the plate to the bottom of the upright, the other holes to the BJs. The dimensions of the plate will determine how much additional -ve camber and +ve caster is obtained, and how much the BJs are lowered. Plus you also keep the 2Gs virtual steering pivot intact, and you add front track - a double-edged sword for autocross it perhaps could be argued, but a win for anything else.

4 fixes in one.

Sadly, illegal for ESP *sniff*

Needless to say, I was not the one who came up with this

 

[jdsoza]

ok so i been thinking about something. why not do what a couple 240 drift guys do. instead of trying to build a frame and arms only to have more stuff go wrong, why not raise everything up and have the body sit lower? they cut the chassis out, weld a new plate and sleeve and it raises the subframe up about an inch and a half. granted a custom steering column might be needed as most on 240's do. the gelometry can sit almost like factory, the body sits lower. a shorter shock and spring installs. i know this moves the center of gravity up, but there are ways to also lower it again. i dont know if this can be applied to eclipses, but it does work on 240's.

 

[Ludachris]

Wow, didn't expect to have a real discussion about true racing suspension.

 

[jtmcinder]

@jdsoza

Aren't the drift guys doing all that mostly to increase the maximum steering angle? I know that the limited maximum steering angle on many cars makes them hard to impossible to drift. (Don't ask me how I know; it's embarrassing.)

@ACM

How sure are you that the lower end of the virtual steering axis stays halfway between the two ball-joints? If the arms were at the same angle (relative to the chassis), then I can see this being true, but I'm not sure that it's true when one arm comes straight out and the other comes almost directly forward. My impression (from, yes, erector-set modeling, so gains of salt called for) is that the lower pivot is much close to the lateral arm's ball-joint than to the compression arm's ball-joint.

@666

The offset between the two ball-joints in the vertical direction is probably the issue. Bummer. But if you solved the roll-center issue with a new sub-frame, could they then move only the compression arm's ball-joint downwards?

@everyone

Has anyone asked a sub-frame builder if they could switch the car over to an L-shaped single lower arm? L-shaped, as on an Evo, such that there would be a second inboard pick-up, further back from the one existing pick-up, to take the force of accelerating and braking. Given that people usually lower these cars to the point that the anti-dive is gone, just give up on it completely. And it sure would drop a lot of unsprung weight.

 

[greengoblin]

@jdsoza

Aren't the drift guys doing all that mostly to increase the maximum steering angle? I know that the limited maximum steering angle on many cars makes them hard to impossible to drift. (Don't ask me how I know; it's embarrassing.)

@ACM

How sure are you that the lower end of the virtual steering axis stays halfway between the two ball-joints? If the arms were at the same angle (relative to the chassis), then I can see this being true, but I'm not sure that it's true when one arm comes straight out and the other comes almost directly forward. My impression (from, yes, erector-set modeling, so gains of salt called for) is that the lower pivot is much close to the lateral arm's ball-joint than to the compression arm's ball-joint.

@666

The offset between the two ball-joints in the vertical direction is probably the issue. Bummer. But if you solved the roll-center issue with a new sub-frame, could they then move only the compression arm's ball-joint downwards?

@everyone

Has anyone asked a sub-frame builder if they could switch the car over to an L-shaped single lower arm? L-shaped, as on an Evo, such that there would be a second inboard pick-up, further back from the one existing pick-up, to take the force of accelerating and braking. Given that people usually lower these cars to the point that the anti-dive is gone, just give up on it completely. And it sure would drop a lot of unsprung weight.

I have been thinking out moving my compression arm down for some time on my setup. Once I put the car back up into the air the plan is to see if it can be done.

Also have been planning to look into a Mod like Charles is talking about. I saw something similar done on a 240 site and it really got me thinking. It may require some custom arms instead or both. It's on the to look at hard list for sure.

The 3g eclipse actually have a cossmember that looks darn near identical (not verified) to the 2g gst and they use a single L shaped arm. So do think it could be done if some one wanter to tackle it. Andrew at Frontline Fabrication talked about doing this. When he was going to build a front x-member. However it should be noted most rule sets put you in the unlimited/big dog class if you start doing thing like custom cross members. At least that how it reads to me.


For those that care:

I have built a JIG so I can replicate the braces that I built for John. So if you want any info on them fee free to pm me. I building a few sets currently for a few more people.


To the OP:

I have a few threads on here about putting bearings in the 2g suspension you may want to check out. For a true track car bearings are the way to go.

Also my build log show the stitch welding I have done. It's on here as well.

 

[ViciousLord]

my new favorite thread.

 

[gixxerdrew]

deleting the front subframe bushings should stiffen up the front of the car. I got nice aluminum ones from black_gst on the link forums. There just isnt any thing to tie that stuff in. I have extra reinforcements there because of the vert and I used those along with roll cage and solid subframe bushings. The car is crazy stiff now in comparison to how it was. I could not be doing what I am doing without that foundation.

 

[jdsoza]

@ cinder. Drift guys sink the subframe to avoid steering lock. They lower too much and then sink the subframe to correct geometry and maintain angle. Without having the steering rack lock. Now i got a question for you. I didnt get my chassis yet so i cant look at it, but which arm has to go through the floor? If it corrected problems id do it, but tie it into something solid like the roll cage, it also be easier to adjust. Any chance you could get me a drawing to bring to my fabricator?

 

[jtmcinder]

If you lower the car (a lot), then both arms will angle down from knuckle to chassis. That's the problem. The lateral arm's angle (and, therefore, the roll center) can be fixed by raising the inboard pick-ups via a custom subframe. It's the compression arm that will be a pain, since it goes straight to the unibody. Raising the inboard pick-up for the compression arm (to get the anti-dive back) is what will require some hacking of the floor, since the compression arm meets the unibody near your feet.

 

[snowborder714]

Here's a couple pictures of the control arms for reference.

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[TSiAWD666]

Well the pictures make it pretty clear why the offset ball joints won't fix the roll-center on a lowered car. They would do nothing but change wheel position, lowering the car a bit but not affecting the angle on that lateral arm.

Might it work for the anti-dive restoration on the compression arm?