A much lighter X1/9?

carl

carl

True Classic
Ever wonder what an X1/9 would have weighed if it had not been built for the massively impressive crash standards that the US thought about requiring? If a 128 sedan weighed in under 2,000 pounds you have to wonder if an X would have similarly been a lightweight instead of the rather heavy (for it's size) sportscar that it is now.

Just wondering.

carl
 
light is good but our chassis are very strong and I take comfort in that when the soccer moms start putting on their makeup whilst barreling down the highway next to me
And if you want to beef up the power plant, while I guess the chassis is ready for that, not that I will ever push that limit......
 
Never ending trade off between weight and chassis rigidity-stiffness.

Light weight chassis can be made trading off rigidity-stiffness. Giving up chassis stiffness-rigidity will result in poor chassis performance. Example would be the original Lotus 7 as designed by Colin Chapman. While light weight, the chassis stiffness-rigidity was poor. It's low weight allowed a high power to weight ratio making it fast in a straight line with mixed cornering dynamics. It was not until many revisions by Catheram to the original Lotus 7 chassis that made it proper and into the performance car it is today.

The exxe can be stripped down to the 1600 pound range, with great difficulty to about 1500 pounds. Couple with with say 300+ Bhp & 300 lb/ft of torque results in a power limited vehicle as with any similar power to weight vehicle.


Regardless of what idealized weight or such might be, there are always trade-offs regardless of who does the design-engineering work. All designs are essentially making a deal with the laws of nature, the better these laws are understood by all involved, the better a symbiotic deal with Nature can be made.

Violate Nature's laws, Nature simply carries on with narry a care.


Bernice




carl said:
Ever wonder what an X1/9 would have weighed if it had not been built for the massively impressive crash standards that the US thought about requiring? If a 128 sedan weighed in under 2,000 pounds you have to wonder if an X would have similarly been a lightweight instead of the rather heavy (for it's size) sportscar that it is now.

Just wondering.

carl
Click to expand...
 
weight vs hp

the car I bought from (mm or) was trimmed to about 1300 lbs. give or take a few pounds, which was the weight intended before the government got so involved in safety. add a 170 hp (?) engine, and it has more hp to weight ratio than my 600 hp Camaro. gonna be a scary first ride...and it won't be in the RAIN!!!!!!
mikemo
and if I am off on this info, mike will set the record straight
 
Well Carl... get one of these like mine...



I had the ladies deliver it, bolted it up and was on the road in 2 hours. Saved over 500 pounds up front which now gave me a 25/75 rear weight ratio and no sacrifice in rigidity. Thank God I have squeaked over 300 hp outta my normally aspirated 1500 so I can Fling It Around Turns in a drift-type manner...

Lightweight Lexan Windshields, Back-lights, and Side Windows are an extra-cost item.

If you wish to do the same... PayPal me your deposit of $1000 bucks to my account and I'll get your order processed ASAP.

(If anyone here believes any of this crap I just wrote... I also have some beautiful beach-front property for sale as well as a bridge in Brooklyn for you folks still frozen in the great Northeast.)
 
You can really save boo-koo bucks over the cost of...

"acid-dipping" the entire body!

Let nature take care of it for you... and its 100% Natural, Organic, and Gluten-free!
 
Wow, trimming an X 1/9 to 1300 lbs. seems impossible. My car is stripped down fairly well with fiberglass hood, Trunk and engine cover and I'm still at 1805 lbs. A list of things I could and may do in the future to lighten the car more would be:

Lightweight race seats -35lbs
lightweight battery -30lbs.
light wieght rims -16lbs
Remove glass - not sure on this, but maybe -40-60 lbs
Remove headlights and motors -20lbs.
Remove windshield wipers and motor - 8lbs

This still doesn't get me very close to 1300 lbs. What else is done to that car?
 
Yeah 600kg would be a tough ask.... I know that 700kg with a 2litre twin cam (lancia beta) engine and trans, a roll cage and really big brakes is possible though... but every body panel (including the targa bar) is fibre-glass save the nose cone and rear panel... no roof, no front screen / no glass at all, windscreen frame removed, doors have steel frame but f/glass skins, no intrusion bars etc etc...

SteveC
 
Yea but

What I meant was, how much do you think the X would have weighed if the factory had used their usual design parameters without trying to meet the US crash standards. We have to get into our way back machine to figure this out.

The X I got was an ITC racer and I'm putting it on the street. I'm leaving the full cage in place (for various reasons) but I'm sure that's adding a ton of weight to the car.

Trim pieces can weigh a ton on the X. The top is heavy, the glove box door is stupid heavy, the dash is very heavy and of course we all know the bumpers are a ton for a 79 X.
 
The LeMons racer is 1750 pounds with about 8 gallons of fuel (about 1/2 fuel cell full) no driver, full driver compartment cage and the usual race car fixings. Figure about 200 ish Whp from the Mazda PP rotary.

So, 1800 pounds for a weight reductioned exxe is reasonable.

The 74' as delivered hovers about 2,000 pounds.


Bernice
 
My 74 is 1800 pounds on the nose

It has all the stock body parts and interior. The wheels are 8" x 13" and are 9 pounds each. The struts are 4 pounds lighter than stock per strut. It has been de smoged and has a lighter exhaust with header. An aluminum flywheel and aluminum Tilton clutch. I remove the top when autocrossing along with the spare tire and tools. A few other changes like an aluminum crank pulley and a couple of other minor changes. The car weighed 2018 in stock form and 1800 after the changes made above.

Charlie
 
Last edited by a moderator:
Rupunzell said:
Never ending trade off between weight and chassis rigidity-stiffness.

Light weight chassis can be made trading off rigidity-stiffness. Giving up chassis stiffness-rigidity will result in poor chassis performance. Example would be the original Lotus 7 as designed by Colin Chapman. While light weight, the chassis stiffness-rigidity was poor. It's low weight allowed a high power to weight ratio making it fast in a straight line with mixed cornering dynamics. It was not until many revisions by Catheram to the original Lotus 7 chassis that made it proper and into the performance car it is today.

The exxe can be stripped down to the 1600 pound range, with great difficulty to about 1500 pounds. Couple with with say 300+ Bhp & 300 lb/ft of torque results in a power limited vehicle as with any similar power to weight vehicle.


Regardless of what idealized weight or such might be, there are always trade-offs regardless of who does the design-engineering work. All designs are essentially making a deal with the laws of nature, the better these laws are understood by all involved, the better a symbiotic deal with Nature can be made.

Violate Nature's laws, Nature simply carries on with narry a care.


Bernice
Click to expand...
Came across this post as I was researching Lightweight X1/9. I fully agree that it is not recommended to trade chassis stiffness for lightweight. This being said, it is possible to shed some weight from the X1/9 by removing things like US bumpers, spare wheel, carpets and insulation, radio and speakers, and replacing with lighter wheels, lightweight door panels, etc. I also recently fabricated a one-piece rear cover, thus replacing the rear trunk and engine covers (minus 11 kg). My 1980 X has gone down from 970 kg to 850 kg (12 %). There is measurable improvement in acceleration, handling and braking. Still on my "diet" list is a fiberglass unit to replace the - very - heavy front hood. My objective was to make my X as light as possible (for vintage racing), while keeping it road worthy and just as safe (more, in fact, since I added a roll bar).
 
The big elephant in the room is money. I would imagine that 1300lb and light would be readily achievable if the entire body is replaced with properly designed carbon fiber. And it would be stiffer. Bernice’s unspoken assumption is that the X1/9 would be affordable for the market they were targeting. If Fiat had the carbon fiber option in 1972 the car that would have been made would not be the X1/9 for the masses but rather a Lamborghini competitor.
 
carl said:
Yea but

What I meant was, how much do you think the X would have weighed if the factory had used their usual design parameters without trying to meet the US crash standards. We have to get into our way back machine to figure this out.

The X I got was an ITC racer and I'm putting it on the street. I'm leaving the full cage in place (for various reasons) but I'm sure that's adding a ton of weight to the car.

Trim pieces can weigh a ton on the X. The top is heavy, the glove box door is stupid heavy, the dash is very heavy and of course we all know the bumpers are a ton for a 79 X.
Click to expand...
Carl, if it hasn’t been mentioned before leaving the cage in for street use is extremely dangerous. Most people have no idea how much the human body stretches under the accelerations that are seen during a crash. Unless you are wearing a head and neck restraint system with a 5,6,7 point harness system your head is most likely to smack hard into the cage elements.
 
It's weird when an old post of mine gets pulled up. Yes, I learned my lesson about a cage in a street car. I had started removing sections piece by piece until ultimately I just had what amounted to a rollbar. The bars that ran front to back just below the top were about 2" from my head. I imagine in a race with a helmet on my helmet would be constantly contacting that bar. You could probably get away with this in a tall sedan with the halo part of the cage much higher than your head but on a small car like the X it would be impossible.

My current X has an Autopower street rollbar and even that is pretty close to my head.
 
carl said:
Yea but

What I meant was, how much do you think the X would have weighed if the factory had used their usual design parameters without trying to meet the US crash standards. We have to get into our way back machine to figure this out.

The X I got was an ITC racer and I'm putting it on the street. I'm leaving the full cage in place (for various reasons) but I'm sure that's adding a ton of weight to the car.

Trim pieces can weigh a ton on the X. The top is heavy, the glove box door is stupid heavy, the dash is very heavy and of course we all know the bumpers are a ton for a 79 X.
Click to expand...
I would guess at triumph spitfire weight
 
I’m really curious what the xxx is going to weigh when it’s done.

Main weight savings are dropping the entire floor pan and removing a few inches of overall height (replaced with carbon honeycomb floor), aluminum tunnel, fiberglass body panels.

Some weight is gained with the motor and trans over stock obviously but the power output is well worth it.

I’m guessing 1500 give or take a few hundred pounds. But again this is not really a fiat anymore.

 
A few other items.
1) Carbon fifer overwrapped aluminum cooling tubes
2) Carbon fiber steering shaft and steering components
3) Carbon fiber suspension
4) Carbon fiber wheels
5) Titanium lug bolts / studs-nuts
6) Carbon fiber brake rotors ( braking could be interesting)
7) Carbon fiber half shafts
8) Mechanical headlight mechanism
9) Carbon fiber steering wheel
 
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