matttheboatman

I've been thinking, if Porsche offered a "Light Weight Edition" in a GT4 how would it be configured?

I am not usually a fan of modding a perfectly good car. Although, in the case of the GT4 some mods are required for regular track use. But, what if I wanted a "great drivers car" and took on a project to make a light weight version of a GT4, and limited my changes to those that Porsche themselves might do if they offered such a car, how would it be configured and would would be my net weight savings?

My thought is that a LW version of a GT4 would be a case where less is actually more - more driver to car connection, more performance, more raw, and perhaps more interesting.

Again, my challenge is limited by only what Porsche would do if they built a Lightweight version themselves - in other words, I can't use any aftermarket components that are not found on factory built cars. And, the car would be built for street use, not racing. Basically, stripped down to an minimally acceptable level that can still be driven semi-comfortable on the street. And, like the door pull straps, some "weight reductions" are really "all show" with imperceptible weight savings.

So far, here is our list of GT4 LW:
All Carpet Insulation removed -1 pound?
Remove all plastic in the fronk -7 pounds
Spec Lithium Ion battery -25 pounds
Spec brakes as PCCBs -40 pounds
Spec non-actuated Xenon headlamps - contributed by ShakeNBake
Remove Stereo and all speakers -8.8 pounds
Change to Lightweight flywheel
Remove power motors on seat slides. -5 pounds?
(Leave in A/C - its just needed)
(Leave in all airbags - safety)
19" Forged Wheels - ShakeNBake, -15 pounds
MR Carbon Doors - ShakeNBake > -40 pounds total est (reportedly -88 pounds incl battery and a poly windshield)
MR Carbon Hood - ShakeNBake > -
Remove truck cover thing as shown in post #16 -3 pounds
Change to lighter exhaust system -10 pounds?
Change to tow straps in lieu of tow eyes -3 pounds
Remove tire inflator kit and tools -5 pounds
Spec smaller fuel tank (contributed by NeedMoreGarage)
Total so far: -162.8 #s


What do you think if a GT4 LW? And, what else would you do / not do?

ShakeNBake

I like it...given what I use the car for and what I enjoy of a fun street car, I'm game.

Standard spec Xenons save a few pounds as well, vs the actuated upgrades.

Fixed/manual carbon seats save a few pounds vs. the actuated height buckets.Though unlikely in the US.

Wheels can be lighter and forged, and 19" for that matter

There a are carbon options on the MR that would be nice, like doors and hood.

Exhaust, especially headers, could be much lighter. The OEM headers feel like they are made of lead.

I think you could shave 100lbs+ off the car pretty easily....but price would add up.

Yargk

Carpet insulation weight unknown. Floor mats together are 3 pounds, trim on the sides of the rear of the car (2 plastic pieces, 2 carpet pieces) removed for roll bar installation are only 2.8 pounds. Perhaps some of the insulation is heavy, but I haven't found it yet.

Big plastic piece over the battery is 4 pounds (weighed), the rest of the plastic together is probably 3 pounds (guess).

Li Ion battery saves 25 pounds

Apparently radio delete is only 8.8 pounds https://rennlist.com/forums/gt4/8814...l#post12417298

You could save 15 pounds total with lighter wheels.

40-50 pounds saved with 2 aftermarket racing seats. (update: nope, only about 30 pounds max can be saved by swapping both seats)

I like the idea of keeping the car comfortable as a street car, so I've decided I like my carpet. I think on a 2 min track every 29 pounds is 0.2 seconds.

matttheboatman

Do you know if the ClubSport or CS MR headers are the stock headers or did they use something lighter?

matttheboatman

I agree, keep the carpet in - we are building a civilized lightweight version not a full race car. Except I would stripe out all plastic and carpet in the Fronk and show white paint to make it "look lighter", weight savings not so much.

We can't go to aftermarket seats because its not what Porsche would do - the Carbon Buckets are our lightest option so far from Porsche.

ShakeNBake

That's a good question I don't know....I do know that the cargraphic race headers feel like they are made of air compared to the OEM units.

BGB has indicated that racers are having trouble with the cat'd motorsports headers that come with the clubsport, so there may be other designs being used now.

They could be even lighter if made of inconel! Your wallet would be lighter to boot.

MarcD147

I could go on a diet and lose 15 pounds....

anything else is silly and way more expensive...

matttheboatman

No doubt that Porsche did a good job on the Cayman to keep the weight to a minimum. Nevertheless, there are components that add weight specifically for the purpose of making the car appeal to a wider audience.

Whereas, a LW version would be more focused, more raw - and I think would step up the overall driving experience.

matttheboatman

The PASM system for the struts is silky smooth - nearly perfect. Incredibly smooth on rough surfaces yet able to keep the car composed with serious track duty. Hard to think of changing it. Nevertheless, I ask the question - would a fixed X51 style coil over save any weight?

drwuss

This is along the lines of the longterm plans I have for mine. I was thinking it would be neat to turn it into something more like the 911r. I was thinking about ditching the rear wing and getting the front aero stuff from the spyder. I already have the BBS FI-R wheels. My next step will probably be a lighter flywheel to help with the 2-3 shift, even my remedial skills engage third before the engine has time to wind down to the proper rpm. I wonder if this has something to do with the third gear failures....

Shockwave

What is the total weight difference between the steel brakes and PCCB? 40lbs?

jmartpr

Are you guys working on the RS????
In order to make it work the GT4 would need to shave 150-200 pounds at least....every little piece will count towards that goal as their is not a big chunk of fat to cut. Some ideas:


- The Carbon hood or the RS saves only a few pounds and the cost is just too high...maybe a cheaper option would justify this mod? How about a Cup hood? Don't know the weight of the OEM.
-If you are going to do the carbon hood might as well do the fenders, roof and maybe doors and bumper covers.
- You could remove the sound insulation below the carpet and in most of the interior and leave the carpet.
- The exhaust needs to be upgraded...Inconel or Titanium anyone?
- Lighter wheels in 19"
- Lighter flywheel
- Radio Delete
- Full Manual Carbon Racing Buckets
- PCCBs
- Li-Ion Battery is a must.....without the top bracket, air compressor and can of sealant.
- Eliminate carpet and insulation in front trunk


I think that beyond this you will have to get crazy on using exotic material and eliminating a lot of other essential stuff for a road car.

stout

Good list.

Mufflers could probably get lighter, rear trunk could be stripped (Perlon could go in to make it useful, as well as in the front), and...

...that's an awfully big piece of glass on the hatch.

twentyseven

Kind of a silly discussion. It's already a 29xx lb car with most of the creature comforts so all of that cost & effort to shed MAYBE 100lb isn't worth it. If you want to improve the power-to-weight, that money is better spent on an engine build or driver coaching - because most of the guys who think like this are still a long way off from setting any track records and there's no sense ruining a great car.

O5C4R

i took everything out of the interior except the floor carpet to fit a full roll cage and was hoping the interior bits would weigh more to off set the cage but they weight just about nothing. only slightly heavy part is the carpet and foam insulation behind the seats. roof liner was impressively light i couldn't believe it.