I use my RX7 mainly for trackdays, but can’t decide if it’s worth trying to lighten it. Does anyone know how much weight would be lost, by stripping the trim, sound deadening, A/C, replacing rear window with plexiglass etc etc. What’s worth doing what’s not……

 

I guess it depends how competitive you want to be because in the end lighter is always better. On the other hand, the AC can't weigh more than 15 lbs. MAX which is fairly insignificant. I took most of my sound insulation out and didn't notice a huge difference in road noise or engine noise but the weight savings was very small (5 lbs. of foam?, probably not even that).

I think other things are more important like relocating the battery, getting rid of the spare tire and jack, and pulling out the passenger seat.

And whatever you do, leave the carpet in or you will feel the heat.

 

For lightening you already listed some of the basics, but I'll add stuff that I can think of.

-strip all the trim/plastic/upholstery
-remove rear bins, spare tire and jack
-remove passenger seat
-remove air pump
-remove air conditioning system
-remove power steering
-lightweight battery
-replace stock pre-cat with downpipe

Here is some other stuff that will save weight but it can be pretty expensive:

-titanium exhaust
-replace rear hatch with CF or FB
-Lexan glass for rear hatch
-C-West CF wing (if you need some rear downforce)
-replace front fenders and bumper with Pettit CF front bumper/fender
-CF hood (get the DRY type carbon fiber)

Those are some of the things I can think of. You can get them from the following:

www.pettitracing.com (hatch, bumper/fender)
www.jt-imports.com (tit. exhaust, dry CF hood, lightweight battery)

 

Thanks for the replies, but do you have any idea how much each of these bits weighs, so I can decide what's worth doing and what's not? I guess if I can't shift at least 100lbs I probably won't notice.

 

if you were to do all the things about i would estimate a savings of 100-150 pounds.

 

just up power, it cost less

 

Power may be the answer in a straight line, but not around corners. I'm not from the land of the 2000mile straights!!! This is a toy for the Nurburgring.

 

Nurburgring, nice

How bout some coilovers and some proper corner balancing for the twisties? Maybe even some seam welding if you really want to go hardcore.

There isn't a lot of weight to be lost on these cars from just pulling stuff out.

 

Any tips on improving handling greatly appreciated, the best (well most cost effective) improvement I've made on other cars is a set of polyurethane bushes, do you know who makes them for the RX7, also what shocks do you recommend.

 

I cant say for sure, but I do know how much most of that stuff weighs. Or at least how much the makers say they weigh.

Weight savings of approximately 75-100 lbs


For all this other stuff, this is how much they weigh.

-titanium exhaust = 8 lbs
-replace rear hatch with CF or FB = 10 lbs
-Lexan glass for rear hatch = ???
-C-West CF wing (if you need some rear downforce) = 6 lbs
-replace front fenders and bumper with Pettit CF front bumper/fender = 21 lbs
-CF hood (get the DRY type carbon fiber) = ???

 

spending money, buying "lighter" components does not make you faster.

If you are truly serious about track driving you should only be concerned about making the car reliable enough to ensure plenty of seat time.

When your skills are such that you simply cannot improve any more then its time to start modifying and/or removing weight from the car.

Way too many people buy the $5000 golf clubs before they ever learn how to swing a club. Cars are no different.

If show and having neat mods is your thing, then strip the car and hang all kinds of new pieces on it. Nothing wrong with that. BUT, if track use is your thing, then your focus should be on your technique.

Save your money, use the car until you are more efficient than it is and then improve your tool.

 

Somewhere out there, there is a website that lists the weight of various components of the FD. It's got some very useful info. I don't know the address, but I bet if you searched hard enough you could find it. Anyone else know what I'm talking about? Someone compiled a bunch of weight info from various FD owners.

 

I have spent a lot of time improving my driving skills and will continue to do so, improving the car is in addition to improving me not instead of. I totally agree with our comment on reliability, a go faster mod that brings your track time to a premature end is no good for nothing. Which is why I’m interested in saving weight as that improves lap times AND reliability and REDUCES costs (brakes, tires etc).

 

It was Gene Felber who complied the list. But the link I have (purplemantis) to the page is no longer current.

I know of one FD that has shed enough weight to be down around the 2500lb mark. Car has NO interior to speak of - no dash, no nothing. Just roll cage and a few of the necessary gauges and instruments.

FWIW
Crispy

 

A guy here in San Diego has an Orange 3 rotor with a Carbon Fiber body that weighs 2250lbs. At least that's what I have been told.

 

Saving weight will improve every performance aspect of the car. I don't think it's all that unrealistic to get the car down to 2500 lb. or under.
Easy and cheap items are, removing A/C, Power Steering, Air Pump, windshield fluid holder, ABS (If you want), Airbag and sensors, jack, spare wheel, bins, interior carpet and plastic, passenger seat, headliner, sun visors, stereo, speakers, dash, gauges and the door panels.
Outside of the car you can remove the bumper supports and windshield wipers.
Some of that is rather extreme, but it won't cost you anything but time, and will improve your car.

The following modifications can be done at certain cost: Lightweight Exhaust (Just remove the exhaust after the down-pipe, cheaper, easier and lighter)
Removing Cats (See above), small battery, ditch the pop up headlights and go with a sleek light kit, a Fiberglass hatch and FAL window will save 56 lb. just by itself. Get a light weight flywheel, carbon fiber drive-shaft, fiberglass/carbon fiber doors, light weight hood, super light wheels with light tires (Like Toyo T1S's) filled with helium , light weight lug nuts, brakes, rotors, pads, lexan windows, a lighter ecu and remove most of the wiring (the stock ecu weighs a ton, and there is a bunch of **** wiring!), convert to single turbo, racing seats, upgrade to lightweight engine parts (aluminum RB plates, lightweight engine rotors), replace all bolts, screws, etc... with Ti, replacements, and get two big carbon fiber tanks of NAWSSS!

The link with all the weights use to be www.purplemantis.com but it seems to be down. Lets hope it's just temporary.

 

Some info here: http://ricemobile.net/cgi-bin/framed/1868/weights.html

 

The 2250lb car to which I think you are referring is this one (CF doors, rear hatch and *ONE* piece nose and fornt fenders) Note lack of even door handles!



And the 2500lb track car I alluded to. This car has all it's original steel panels except for the OE aluminum hood



FWIW
Crispy
- a picture tells a thousand words

 

BTW you can get a lot of those parts at 7parts.com

 

For what you want say you are going to do and the way you are talking about it, you should definitely do coilovers. If you are going to go through all the trouble of decreasing unsprung weight, then you should go coilovers and have a good shop corner balance the whole thing.

Everyone is going to have their own opinion on what setup is best, but I have a very strong preference for Konis. Been using them since 88 and when I don't I regret it. I would say get the Konis sport adjustables (or double ajustables if you have the quid) and the Ground Control coilover spring setup. Or try one of the full coilover kits from rx7store.net. Depends on your budget.

You will get more out of a properly tuned suspension than you will from trying to drop 100-200 lbs. Just look at the guys running Touring car that get the extra weight added when they win. At the end of the season, P. Cunningham and Hugh Plumb and Will Tuner have 100-200 extra lbs on their cars and still manage to win!

 

btw - when are you hitting Nurburgring? I fantasize of driving there...

 

I go to the 'ring about 4 or 5 times a year, I've got one more trip planned this year in November, but will be taking my EVO7. The 'ring is a must, just check puplic opening times and show up, there's always people there to give a quick introduction to the 'line'. I'll be there in the RX7 plenty next year.

 

You are one lucky bastard! Can you PM me with a link of where to look for those public open times? I've looked into it once before, but there is no way I can afford to get me and my car to DE at this point in my life.

You will definitely have your hands full getting your car sorted once it arrives from JP - between suspension, maint and determining its track worthiness/reliability.

 

Do me a favor and post pictures of your car on the track. I really envy you!!

 

Every thing you need to know about the ring is at www.nurburgring.org