The 2006 C70 has a strut tower brace bar (metal stiffening bar connected between the tops of the two strut towers in the front suspension). But my 2007 (received in late January, and I think built in December 2006) doesn't have this bar. I'm trying to figure out when it was designed out - was it for the full run of model year 2007, or did it happen "midyear"? Most of the pictures of engine compartments in on-line reviews show the brace, but most of the reviews were of 2006 cars. Does anyone know what the rationale was for taking it out? (I know that it's in the way if you need to remove the battery cover, and perhaps it isn't all that necessary, but I thought it was a pretty nice design feature, for improved chassis rigidity.)

Also, has anyone looked into mounting the 2006 brace into their 2007? I've seen a fair amount of discussion regarding strut tower braces (both original equipment and from other vendors) for the S40, but I haven't found any prior discussion of this subject for the new C70.



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In case anyone cares, I found the answers to my earlier posted question. The "external" strut tower brace bar that is equipped on the 2006 C70's was eliminated during the 2007 model year run, probably sometime around Novermber or December 2006 (manufacturing date). A design change was implemented in the basic C70 platform/chassis that essentially integrated the brace, thereby eliminating the need for the bolt-on brace.

A portion of the new "integrated" brace is visible. It attaches to the rear edge of the driver-side strut tower, and then runs behind the battery, where it is barely visible (versus the 2006 brace which is on top of the battery). It then sort of disappears into the bulkhead structure, but it continues on (hidden) to the rear of the passenger-side strut tower, where the attachment point is hidden from view by the sheet metal. My dealer was nice enough to get a photo from the factory to show the new design (on a partially built car), but it didn't really show much more than the visible portion that you can see on a completed car.

The new C30 is also using this modified platform. If you go to the www.volvocars.com web site, you can get an idea of whatthe integrated brace reallylooks like on the C30 "interactive" web page. (I looked at the US site, but I assume it is basically the same on all country sites.) Click on the Safety tab of the interactive page, and then click on the blow-up box that shows the "unique front structure". The see-through, exposed view of the chassis clearly shows the integrated strut tower brace. I can't swear that the C70's implementation is exactly the same, but the part that is visible looks identical.

My conclusion is that the new integrated brace is probably equally as effective as the 2006's bolt-on brace, and has the added benefit of not blocking removal of the battery. Of course, it doesn't look as cool! But from a handling perspective, there is probably little or no additional benefit to be gained by adding an external brace.

 

The purpose of the strut brace is to tie the 'tops' of the McPherson struts together to keep them from flexing. On a convertible it of course becomes even more necessary to have a brace because of the loss of rigidity when you lose the metal top. The reviews that I have read so far on the "new" convertible is that it still has considerable chassis shake. I wonder if adding the conventional strut tower brace would help?

r.

 

It is just my own opinion, of course, but I don't think that there is much interaction between the traditional "cowl shake" of a convertible, and the particular kind of bracing that is provided by a strut tower brace, whether it is an external, bolt-on part, or done in a more integrated fashion. "Cowl shake" is a bit of a misnomer, in that the flexing that results in cowl shake is really a bending/twisting of the floor pan and frame/chassis structure between the front and rear suspensions, and underneath the seats, etc. With no roof, and no B-piller, all of the stiffening of this area must come from the floor pan and underlying frame/chassis itself. The reason it gets called cowl shake is that if your body and the seats are on the flexing part, it will feel like the bulkhead/cowl (and the attached steering wheel) are shaking.

Cowl shake on the 2006+ C70 is hugely eliminated/reduced, at least as compared to the prev. generation C70. I wouldn't say it is totally non-existent, but the C70 is in the upper tier of convertibles for having minimal cowl shake. I was a bit surprised to seethe comment about reviews all mentioning significant cowl shake. This was certainly true of reviews for the previous generation, but the vast majority of reviews for the current C70 have talked about solidity, minimal cowl shake, etc. My own driving impression is that the new C70 is as solid, or solider than any of the other current convertibles I test drove, whether soft-top or hard-top. I haven't driven the new BMW 3-series convertible, though. It is supposed to be very solid as well, so I am interested in seeing how it feels. It mayend up beingeven solider.