308/328 dry weights

My experience with weighing tires has been the original version XWX Boxer 15" tires vs the new made in Serbia version is the new tires are each 7 LBS lighter than the originals. The new XWX's have a much thinner bead and if I recall correctly its a poly belt vs the original steel belts that make the difference. A 7 LB unsprung weight reduction on each corner is a great thing not to mention 28lbs less overall.

 

They can't still work right can they? I've been 3/4 tire shopping and all the premium tires I've looked at are +/-1 lb of each other. I bought a car for my son about a month ago and it had a set of brand new amazon specials on the rear. The specs on them look fine and they felt fine in normal driving but were just plain weird (in a scary way) when I pushed it at all. They went in the trash and it was a night/day difference getting the OEM Michelins back on....I would never have believed the difference had I not experienced it for myself so I'm not sure I would want light weight serbian tires for anything but show use

 

Have you done anything with the breaks? Girodisc's set claims to save 15lb over stock, though if you're running 14" wheels it may not fit (they say they will for 16").

Where is the most noticeable improvement after dropping the weight, handling or power? Both?

 

They work great and I had my BB up to 250kph on a number of occasions with them. I prefer the ride and handling of those over an aftermarket rim / tire combo, they just suit the car.

 

Girodisc uses a Wilwood calliper I believe, correct me if Im wrong and a set I installed on a 308 required 16" rims minimum. They look good and work better than the stock setup as they should. I didn't weigh them but they're definitely lighter having an aluminum hat rotor and calliper.

 

I believe you when you say they ride nice but they are not the original tires are they? The originals were steel belted weren't they? which is done to keep the center flat so the entire tread contacts the road but does give them a harsher feel, which in turn requires different suspension setup, much like standard radial to a run-flat. On poly tires the center crowns so its always the center that wears first vs steel belted where the corners usually where first and they handle quite differently as a result. I remember seeing adds for steel belted tires in the 70s as they were still considered an upgrade option but by the 80s I'm not sure any cars still came with bias ply tires?

If you like them you like them, that's all that matters I guess.

 

That's correct, they're Wildwood calipers. The claimed weight savings up front is 7.9lbs per corner, and 3lb per rear corner (it uses the stock rear calipers, which is why the weight savings is less in the rear). Tarox also makes a brake kit, but they don't provide weights.

Between the brakes, battery, alternator, exhaust, smog, and radiator, you should be able to shave about 3+% of the car's total weight without a lot of work (but with a significant amount of money). After that, the work gets more complicated (more than just bolt-on stuff - fiberglass panels, etc.), but losing 250+lbs without sacrificing comfort (keeping AC, stock interior, etc.) is attainable, especially in the US cars. I imagine a sub 2700lb gtb would be a lot of fun, especially a carb'd Euro car (and doubly so with a lightly breathed-on engine).

 

The Girodisc setup I did. Powder coated the rears to match.

I don't have a tire here to verify the belt composition but I'd like to think the tire today is better than the tire from the 70's despite the tread and look. The compound is different because of environmental reasons as well.

 

I promise a 70's style tire, regardless of its weight or compound updates is NOT a performance enhancement over modern tires...that's kind of the exact reason modern tires are modern Michelin shows the XWX as a 100tw, with a modern asymmetric 100tw tire you will be pulling 1.2-1.3g and a 200tw will be really close to 1.2g, not the 0-.8-0.9g the 1970s were delivering....so it doesn't matter how much weight you pull off, without modern tires the car will not be modern fast.

I haven't not seen shocks/springs mentioned on the weight reduction list, but I'm pretty sure losing the large OD and very long factory springs is a 20+lb weight reduction and an aluminum shock also helps. Plus the handling will be night and day better if you chose spring and damping rates wisely.

 

Current battery is their Group-75/78 Lithium Car Battery - 40 Ah. Which has been fine so far, but not sure it can keep up with an AC compressor. Alternator has been changed to the 175A output made by Wosp with a Ferrari spec housing as sold by Classic Retrofit. AC compressor is an unproven Ebay purchase. The light battery is of course not part of the AC conversion, and one could do it with a one off install of a generic high output alternator. As I'm focused at the moment on just driving the car this season, the final AC install may not be ready for testing until next year.

 

A stock flywheel and clutch is about 34lbs and the setup I have is 17 iirc and it could have been lighter. So there is 15-20lbs to be had there

 

My car has 16's on it, no plans to run an XWX because I'll be running 3 piece rims in the near future. The gist was that the new XWX sheds unsprung weight compared to the originals and there's no other tire I would want on a carb'd boxer or if I had a 76 dry sump 308. Even with superior tires to the michelins, it's still just a street car that see's train tracks, potholes and curbs but it'll never see a skid pad.

My car has aluminum coil-overs and a quick ratio rack which the PO added.

 

Did you have it machined? How does that affect drivability? I've heard that lightened flywheels are sometimes uncomfortable on the street (car lurches on take off, etc.).

 

Building my track 308 i obviously focused on weight a lot.

I basically removed EVERY bit an piece not required and replaced numerous parts for lighter options even including front and rear end

Before all the work i had the car weight measured and it's ready to drive weight, (i call it like that as i drove the car to the scale So incl fluid, gas etc was 3110LBS
After all the work was done did this again and it was 2350lbs. same scale. no joke.


BTW i added a turbo so the power went up from 217 to 294 BPH


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Skip pads don't matter, but it is fun to go play autoX now and again

I don't want to tell anybody what tire of wheel to pick....there is no "right" answer and where and how you drive for sure changes the answer dramatically. I really just meant as a caution to those talking about weight reduction to improving performance, good tires are step 1 in getting any car to handle well and why ferraris have always come from the factory with the best tires available at the time. If you want it to drive like when it was new, it needs the original wheels and tires but to drive like a new car it needs something newer.

Last Saturday my son and I drove up to the local gokart place to do battle. On a long off ramp we saw an old ford falcon up ahead....mid 60s? and pretty small looking. What really caught our eyes were the tires, they looked about 1/3 the width of the other cars around. The car also had at least a couple inches of body roll in spite of the fact that he was driving below the posted recommended corner speed. Cars have come a long way.

 

I made mine years ago, but if you Google aluminum flywheel there are a few options that pop up.

I'd heard all the light flywheels are scary and bad so I originally left the flywheel stockist and just did a 7.25" race clutch which is smaller andc1/2 the weight of the stock clutch....the only thing I noticed is the clutch worked right again as I'd fried the old one. So that is my V8 experience. As part of the V12 conversion I re-used the 7.25" clutch and made a pretty light flywheel and again noticed nothing bad about how it drives or idles or anything. It's snappy free reving it is about all I can say.

Here it my very first drive....it just drives and it's an honest to God race engine with a hp peak north of 9k rpm



I'm pretty certain the original stuff was designed around standard clutches and old low torque starter motors, not any of the stuff I heard people worrying about when they talk about lighter flywheels.

 

@st@ven, am I remembering you made carbon fiber everything? I'm remembering a thread with doors being made and thinking that was you and that I need to go have another look at that.

 

Finally had an opportunity to weigh my wheels:

Front - 17x7.5 Compomotives 225/45R17 Firestone Indy 500's - 42 lbs.
Rear - 17x8.5 Compomotives 255/40R17 Firestone Indy 500's - 45 lbs.

 

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Here’s mine without the tire. Is yours about the same weight without the tires?

 

Mike,

Tires weigh 23 lbs. Front and 24 lbs. Rear.

That would make my wheels 19 lbs. Front and 21 lbs. Rear.