Evo VS DSM Unibody

[eclipsh]

When I went to "test drive" an EVO 8 when they first came out the sales guy said the frames were braced to make them more rigid than stock Lancers.

Does anyone know where the bracing is and if similar steps could be taken in our cars? After all, they are both unibody construction, AWD and the same weight. The frames should be capable of the same rigidity without adding a full roll cage, right?

One thought a buddy and I had was to install a simple k-member at the rear strut towers instead of just using a tower brace. Maybe attach it to the strut towers and the bolt holes for the rear seat belt retractors or lap belt bolts.

If I'm not making any sense it is due to the cold medicine spinning my head right now.

 

[housegsx]

I think the evo just has better seam welds than the Lancer.

 

[mavisky]

I printed off an old PDF from Mitsubishi back when the 7 was released and they go through and talk about all sorts of cool stuff in there including where they beefed up the chassis. I'll have to try and dig it up and scan it in tonight.

 

[asian312]

Sport Compact Car did a cover story on Opera's S2000, 350Z and RSX. All these cars had their chassis strengthened by having new OEM pieces welded over the stock pieces in specific structural points. Here are some links:

http://www.sportcompactcarweb.com/features/0611sscp_opera_performance_honda_s2000/index.html

http://www.sportcompactcarweb.com/features/0611sccp_opera_performance_honda_rsx/index.html

 

[eclipsh]

Wow... beautiful time-attack cars but I can't imagine what would happen to either of those two cars in an accident.

 

[eclipse2via]

Immediately visible in an RS trunk(because it has no carpeting), behind the seats under the parcel shelf has big crossbraces linking right in front of the shock towers. And at the extreme rear, a RS exclusive brace runs under the mats. And pulling the seat it seems like there are a lot of seam welds, but then again since it has no sound insulation it may just show more than is typical.

 

[jtmcinder]

Besides the difference in the details of construction, another huge advantage of the Evo over all DSMs is the fact it has 4 doors, bringing the B-pillar closer to the center. That huge gap between the A- and B-pillars in a DSM makes it torsionally (twisting-wise) weak.

- Jtoby

 

[eclipsh]

Besides the difference in the details of construction, another huge advantage of the Evo over all DSMs is the fact it has 4 doors, bringing the B-pillar closer to the center. That huge gap between the A- and B-pillars in a DSM makes it torsionally (twisting-wise) weak.

- Jtoby

I wonder if doubling up the steel around the doors would help that (like the above fabricator did at the strut towers etc.)

It'd probably be more work than a roll cage but it would in the way less.

 

[eclipse2via]

My DSM was down for an extended period when I first bought my Evo. The first highway corner I hit hard when I put my GSX back together, I thought "Damn this thing is floppy!"

I'm hoping a bolt in cage will even it out with the Evo. I don't think any small gusseting or reinforcement will help enough, sorry.

If you really want a DSM as stiff as a Evo then build a cage that incorporates both the front and rear strut towers. That means going through the firewall. Also include a knee bar for tying the main front posts together.

 

[eclipsh]

Here are a few good photos of a SBR's Rally Evo9.

I found them and thought of this thread

Pagosa DSM and I will be trying a k-style reinforcement bar at the rear strut towers to try and help with the rear end flex this summer. We'll let you know how it works out after it is done.

MAVISKY: did you ever find that PDF of the Evo body reinforcement?

 

[spinninfwdlaser]

I do not think anyone mentioned that EVOs have a chassis cross-brace, similar to BMW M3 lightweights. Its also known as an "X-brace" that connects the frame at 4 points, connected by grade 8 bolts, and holes in the frame . Works well, and some people have decided to try and make them for DSMs with awesome results. Any reputable welder or fabricator could make this for you. If anyone would like a link to a picture of the brace I am speaking of, I would be happy to get it for you. Hope this was helpful.

 

[eclipsh]

Post that link now or be forever scorned!!!!!!

Yeah, that link would be great, thanks

 

[spinninfwdlaser]

Here is a link to a picture of a chassis cross brace for the BMW.
This is the brace I spoke of.
http://www.bavauto.com//assets/product_images/hardpart/51718410212.jpg

 

[eclipsh]

Where exactly is that bolting in at? RRE suggests that the front of a 1g AWD is sufficiently braced from the factory. So where else would such a brace go?

 

[RipperXX]

You guys know Top Gear did a little testing with the Evo VII vs Evo IV and the 7 was faster around the track. They contributed it to the fact that the 9 seemed to have a softer more plush suspention to apease car buyers and oversteered more. The VII had a noticeibly siffer suspention with much less body roll and well was just faster around the track.

So personaly if I had a brand spanking new Evo, I think I would look at some stiffer settings.

 

[spinninfwdlaser]

Where exactly is that bolting in at? RRE suggests that the front of a 1g AWD is sufficiently braced from the factory. So where else would such a brace go?

Maybe, but if anyone ever wanted to get insanely serious with just a kickass track dsm, (not sure if collier had one) I would look at one. It bolts to your frame, at the front right, left, rear left, rear right. Holes must be drilled to perform this modification. E36 BMW guys said this is single handed the best suspension upgrade ever for their vehicles. It connects all four points of the chassis to make for one hell of a tight frame. I suppose it is almost like when you use your arms to brace something.

 

[eclipse2via]

Here is a link to a picture of a chassis cross brace for the BMW.
This is the brace I spoke of.
http://www.bavauto.com//assets/product_images/hardpart/51718410212.jpg

That's just a lower arm brace. Evo has bars stock, a more complicated brace is available from Tanabe, Cusco and others. RRE offers a lower bar for 2G and as stated they believe the 1G is well braced in that area.

 

[spinninfwdlaser]

Cool, I just thought I would throw that idea out there. I now see I was incorrect in thinking.

 

[krisj144]

my evo felt just as stiff right off the factory floor as my caged gsx. It's tough to admit, but the evo has far superior engineering built into the chassis than our dsm platforms did. Sure, you could add a full cage which ties all the strut towers together, but that would also increase weight well above what the evo is capable of.

Another big upside to the evo is the aluminum suspension components. Much better than the stamped steel parts which comprise the dsm understructure.

 

[Jon Lane]

The Spyder back crossbrace looks interesting...

 

[eclipsh]

I'd had some other odd-ball thoughts about ways to reduce flex after looking at the door of my friend's '96 Trans-Am. Rather than a single latching point like our DSMs have, it also includes a large pin which the door slides over when closed to help stiffen up the door so there are two connecting points on the rear instead of one. I don't know if it would be worth incorporating this into our doors AND rear hatch to help out or not. It does not require an extra latch, just a matching key in the corresponding piece.