jturbo

What percentage of chassis stiffness is foregone with the 1971 911T targa vs. the 1971 T coupe? Is there any way of stiffening the chassis of a targa or is it not worth it. ie: too much chassis flex to begin with.

Also, I have seen tracked 914 Coupes and all 914's are targa? Are the 914 Targa chassis more stiff than the 911 Targa chassis?

LaughaC

This is an interesting question.

Someone makes bolt-in braces that supposedly stiffen a targa without adding a cage. Pelican and/or Performance products advertised these in their catalog, but I've never known anyone who tried them.

TroyN

This doesn't answer the question on the differential in the older 911s but should give you some idea that there is a huge difference in stiffness:

https://rennlist.com/forums/showthre...ferrerid=14761

That said, I have installed the Cambermeister strut brace, the Targa stiffening bars and billet motor mounts, and the car feels pretty solid (noticed most of the difference with the strut brace and motor mounts, not so much with the bars but figure any little bit helps), with the top on. I know it'll never be as stiff as a coupe though, without a very full cage at least.

Mike Murphy

I could tell a difference when I drove a 3.2 coupe and then got back in my 3.2 Targa. I think if you're into the tight cockpit or you like going around the track, then get the couple. If you like convertibles, get the targa. I notice the cowl shake, but it does not bother me.

BlackPearl

Answers (IMHO):
1) Don't know the %, but the flex is significant when tracking the car. You can get 'stiffening' hardware, but keep in mind the Cabriolet's and Targa's have additional reinforcement in the pan/body, that makes them around 200# heavier than a coupe. Adding the stiffening hardware will increase the Targa's overall weight even more. Coupe will be lighter, with no inherent flex.

2) 914 is a very different chassis than a 911, and it's mid-engined. So the flex and weight characteristics are different between 914 and 911. Apples to oranges.

Just my opinions. Other may differ.

jturbo

Does the loss of chassis stiffness translate to significant / noticable handling and road feel loss when driving agressively on the street?

Any Opinions?

TroyN

The body flex is noticeable on the street, especially with the top off, but the car still handles very well. Since you don't need to clip apexes with inch-accuracy on the street, it's fine, IMHO. I bought my Targa for use as a track car, much because in CO Targas are much more common than coupes, and because I wanted to be able to enjoy the top-off driving, and have been pretty happy with it so far.

If I got to the point where I needed an ultra stiff suspension and chassis, I'd get a coupe.

pu911rsr

I have been in Targa's on a race track that really handle and haul A$$ but the first time I saw one flip and come down on it's roof cemented it for me - I would not get in one one on track w/o cage. Great street cars.
Phil

Mike Murphy

Honestly, this is hard question to answer. It's like going to a restaurant and grading the food quality: it all depends on how much of an expert you are. If you are used to $500-for-two Montreal-French dinners, then your typical high-end Chicago Chop House might not make the grade...

This reminds me of the question about "which tires should I run." Some people run all-season tires (me) and some run PS2s. I believe that I am not a good enough driver to notice the difference in running PS2s. A talented driver could whip me on street tires even if I had racing slicks.

You know, there is another problem with the Targa besides chassis stiffness: increased weight.

So to answer your question, I do think there is a noticeable difference in that if someone on the street were racing you in your Targa, they will probably be faster. But you can always beat them if you buy a newer Targa Porsche than their Carrera Coupe.

LaughaC

Any pics of roof damage to a flipped targa? I'm wondering how strong it is.

Mike Murphy

Well, mine is mostly made of glass, and that glass by the way, is kind of expensive. I don't know what the actually support beam is made of, but the glass does add to the rigidity.

sjanes

The targa bar is strong.
The windshield pillar? Not so much.

IslandmanPA

If I were looking for a car to dedicate to the track I'd definitely go the coupe(no sunroof) model! But for pure fun and fresh air, cab or targa!

Serge944

For a race car, targas are the way to go. With a proper roll cage, the difference in chassis stiffness between coupes and targas becomes irrelevant.

You can chop off the entire targa assembly, get rid of the ridiculously heavy rear glass, and put in a full CF or FG roof with lexan windows.

With enough work, you can have an 1800lb 911 race car (with a 3.6 even!).

Mike Murphy

Interesting perspective; good points too.