I have been reading all of my old porsche mags, getting all excited about april 17th (the first day i can take the 83' targa7 out of the garage and start her on her diet...)

but im wondering...speed holes...where are safe places to put holes on the chassis to reduce weight...porsche recomends the door hinges etc...but does anyone know how this applies for an RX-7?

 

take the targa off.. it weighs about 10lbs.. lol.. and the aero drag it creates will also be a factor at speeds. As for lightening.. there is a lot you can lighten in the hatch.. then relocate the battery back there.. while you are lightening.. make sure you try to keep your 50/50 weight distribution. Try to lighten your rotating mass as much as possible.. as this will be much more important.. Things such as lighter tires, rims, brake rotors.. (have them cross drilled), lighter driveshaft.. its all about how thorough you are and how much you want to spend. Lose the hatch struts.. you wont need them.. the rear wiper accessories.. im not sure if this is a race car only or not tho..
good luck.. and weigh it all at the end.. and tell us how much ya lost

 

Not entirely necessary. RX-7s were slightly nose heavy to begin with, and even then it's all out of whack because the ratio of sprung to unsprung weight is so different front to rear. Weight distribution basically tells you how you need to set up the suspension. A well set up suspension with crappy distribution will beat a crappy suspension with good distribution anyday. (Look at the 911's and their racing record... they were good because the factory became experts at suspension tuning, because the design of the car mandated that they *had* to become good)

Best handling car I ever drove was badly nose heavy.

If you're going to concentrate on optimizing weight distribution, focus on removing weight from the ends of the car, and/or moving it lower/towards the center. That's the real advantage of moving the battery to the bin area, gets the weight from up high and at the nose to down low and closer to the middle.

 

hum.....ok good good...but the RX-7 being nose heavy??? they ahve a perfect 50:50...how would they be nose heavy??

its funny i didnt realise the frame for the bin was so heavy, i removed it and it must have weighed 20 pounds...next i i guess i start drilling!!

 

what about the door?

theres alot of weight on those suckers

 

I don't think they are exactly 50:50 to start with, they are close though. But it must depend on a few factors like driver/passenger? their weight? how much gas in the tank? etc..

 

i'd like to know about where it's safe to take out parts as well.

i just removed the bracing from my hood (tin snips) but i've run out of other things to take off to shed weight

www.cardomain.com/id/fbdrifter shows just how much i've done. but i want more! haha.

 

thats one er-um clean interior...is removing the bracing on the hood advisable? i would assume it is there to give strengh but for what? it cant be all for when you open the hood...can it?

the insides of our cars look very alike drifter...i hope to re install carpet though...maybe some custom cut ultra thin stuff

 

well, the hood doesn't really offer any bracing to the body itself, so it's only purpose is to reinforce the hood itself.

just don't let anyone jump up and down on it hehe. i'll start looking around tomorrow for more places to shed weight...

 

Not sure about the 7 hood but on other cars (SE-R) when the hood bracing is removed the hood flexes at speed and creates some nasty drag.

I've swapped out the electric windows for manual windows, removed the rear wiper motor assemply, the insulation under the carpet (not the tar, that will be my next project), air pump, all of the A/C stuff except for the core under the dash and I think that is it so far.

 

so far so good. the hood seems thick enough that it doesnt even need the bracing.

 

my hood dents in very easily with the bracing intact... I dont think it would even support its own weight without it...

 

The stock hood on my '80 would flex up 1/4-1/2" at the rear corners and sink in a like amount in the center of the rear edge at superhighway speeds. From all the aero pressure in the middle, and all the underhood air trying to escape at the sides.

I have been considering removing the hood bracing for a long time. Seeing my friend's 240Z hood made me think more of it. (6' long and no bracing) However, the RX-7 hood is fairly flat, and there is a good amout of aerodynamic pressure on it because of the way it is angled - it'd probably push down in the middle. The 240Z hood is really convex so it can withstand any aero pressure on it.

 

how much weight do you figure you would save with the bracing gone?

do you think that you could eliminate the flex by simply installing retaining pins at the corners and maybe putting some basic bracing up at the front?

 

the bar in the middle of the car.....the one just behind the seats,, it is about 2.5 inches high and runs from the LHS to the RHS, what is ist purpose? im assuming it is for rigidity, but can anyone confirm this?

 

It's part of the main structure of the car. Definitely don't want to lose that!

 

~5lbs

i mounted my hood with hood pins at the rear. no shake at 115mph and everything seems normal until you press down in the center of the hood, flexes easily...but pops back into shape.

only complaint is when you go to lift your hood it's all floppy and wants to slouch to the side lol.

 

That should be easily fixed with the installation of a couple of hood struts. Something I've been wanting to do for.. well, since I first opened the hood of my first one. I have a long standing dislike of hood props.

 

Cut the whole floorboard out, and go tube chassis. Ooops that might not be cheap tho. Nevermind.

 

Wouldn't struts nullify the reduced weight?

 

Hood struts barely weigh more than a prop rod, especially considering that they only have to hold up a light hood instead of a mongo hood like some other vehicles.