Project X300, this could get expensive

[OliverSedlacek]

I've set myself the long term goal of upgrading my XFlow powered 7 to 300 BHP/ton and I'm blogging progress. The targets are to get the weight down to 525kg and the power up to 160 BHP. Last time I checked, the weight was 540kg and the power was estimated at 150 BHP.

 

My recent alternator problems were an excuse to lose a bit of weight, so I stumped up an extra £240 (ish) for a Brise/Denso alternator. Disappointingly, this only saves 0.73kg, but I recently bought a mini-mill so my first milling project was to make some new mounting brackets. This improved the weight saving to 1.13kg for no significant cash expenditure, but plenty of time spent covering everything in swarf.

 

So now I'm 7.5% of the way to my weight target, but at this rate it will cost me £3200

[6speedmanual]

.....and for a moment I thought you were resoring a 1990s Jag XJ6 !

 

Anyway good luck with your project. The way to weight saving is to question the requirement and function of everything. You will probably be able to save as much weight as you did with your alternator F.O.C. by getting rid of the multitude of excess washers used all over the place by people building 7s.

 

Peter

[Shaun_E]

Hi Oliver - it was great to catch up with you at Penn.

Give Michael Calvert a call. His Xflow 7 weighs less than my Superlight 😳 and he has gone to great lengths to remove excess weight - he even trimmed the ends off lots of bolts . His car is a de-dion and weighs less than 510kg so your target on a live axle is definitely achievable.

Shaun

[metal mickey]

Alloy bellhousing

Lighter wheels

Ti nuts/bolts

Raceco exhaust 😬

aeroscreen.

 

[David Brown]

What do you weigh - jogging might lose another 5kg

[Jason Plato]

put less petrol in ?

[jakeandlizzy]

aeroscreen.

 

...but not a brooklands as they are as heavy as the normal screen!

 

but to continue:

 

lighter driveshaft

lighter flywheel

tillets

remove any honeycomb protection

 

[Shaun_E]

If you still have a Banner or similar battery then replacing with a Redtop 15 or equivalent will lose a couple of kg. Replace with one of these will lose quite a few more (at somewhat large expense though).

Wheels and tyres are another place for a big weight saving. Avon CR500 are a lot lighter than most road tyres and certainly lighter than A048R/R888 type tyres. Mag rims often come up for sale on here or you could try the 7Tips ones (see link above) or Image lightweight 3 piece.

Losing the windscreen (and therefore the wiper motor, etc.) is a big step forward but I guess you'd rather keep them! Likewise the heater.

Ti silencer such as Raceco would be good.

[Phil B]

Alloy Crossflow cylinder head?

 

Allows bigger valves and with roller rockers gets you more lift, put together gets you more power and saves weight, double whammy!!

 

Phil

[OliverSedlacek]

Weight is ready to roll (quarter tank of fuel) and to include full weather gear. I've already got a steel flywheel and an alloy bellhousing, but wheels, alloy cylinder head, titanium silencer and propshaft are still under consideration. What I'd really like is an alloy diff carrier to get the unsprung weight down.

[skeetsy]

If you are looking to save weight then this website has some good ideas

 

I like the idea of drilling the centres out of all non structural bolts

[Phil B]

Ital or English axle?

Alloy diff nose for english axles are readily available, around £350 from SPC, but I haven't seen one for Ital. The old midget, minor axle had an alloy diff nose, but as the ital axle is more of Triumph origin I have no idea where to look. If you have an Ital axle then you may be able to use the alloy brake drums which Canley Classics sell as a Spitfire/Vitesse rear brake upgrade.

 

If you want to lose unsprung weight, have you got alloy front calipers and hubs yet? You could expect to lose about 8-9lbs per side, assuming you stay with 232 solid discs and use Hi-Spec calipers. You could even save a few more ounces by fitting drilled discs.