Light Weight Normally Aspirated Or Heavy Weight Force Fed???

[Duk]

I've not seen 1 for the V6 engines, but me thinks it would be a much better way to go about creating a big bore version of the engine.
Weiredly enough, I have absolutely no idea how and where people get slabs of metal like that.
I only work at a steel works, but in the past when special bits of metal are needed for the machinists to make something, that stuff just appears like magic. 

Just purely for the sake of it, does anyone know of a suitable grade of steel that cylinder liners could be made from?
Nearly all cylinder liners are made from some type of iron and for good reason. But a couple of slab of suitable iron would be rather difficult to find.
The other option would be to follow in Porsches foot steps and make a monosleeve from a suitable grade of aluminium and have the bores Nicasil treated after final machining.

[Al Campbell]

Plus there is the problem of how carbies actually work, especially when idling.
When tiny amounts of fuel are expected to be drawn out of the carby and into a small amount of slow moving air and maybe having to cover a reasonable distance, fuel falling out of what little air movement there is, is very real.
The notion of carbies being accurate and efficient is purely rediculous.
Yes, if sized and tuned correctly a carby(ies) more can deliver the correct amount of fuel and present no significant flow restriction when the engine is operating at peak power. In the same way that a mechanical advance distributor can also provide the correct ignition timing that the engine needs at peak power (or peak torque, but chances are not both). But that is a very narrow operating condition and 1 that is rarely used in a genuine road car.
Expecting a carby or 2 and a purely mechanical type distributor to be able to accurately deliver fuel and correct ignition timing in a force fed engine is even more rediculous.

I agree that carbies can't do the fine matching to just about any situation that EFI can (not the L-Jet with no feed-back). What always amazed me was the lengths that some carbies went too - such as in Rotaries with their 4-throat, dual stage Niki's with dash-pots, vacuum actuators & mechanical throttle links & other gubbins all over the place. And I love what the Gregories manual said about any problems in the carby on the '89 corolla: "Very well made precision device. Forget trying to fix it - replace it" - or words to that effect.


Keep working on this discussion people. I've sold my house to down-size, the wife has stated as one of the requirements for the new place is "A Garage for you, to get you out of my hair". I plan to have some cash for another play-thing car and have looked at all the options butI keep coming back to the GTV6 - but I can't decide on the engine.

[Duk]

To be able to match the power to weight ratio of my big fat F6 (1720kg) in the Alfa, the full weight (1350kg) car would need 284hp.
If 50kgs could be dumped from her, the power required would be 273.
And down to 1250kgs,  262hp.

Getting the car's weight down by 100kgs would be a big challenge. Especially as keeping air conditioning and power steering is a must (well, maaaaaaybe the PS could go).
Getting 260hp from a normally aspirated 12 valve is doable (if Richard Jemmison's claims are anything to go by).
But it would be impossible to match the pure spread of torque that the F6 can dish out, unless going for forced induction. And even then the centrifugal supercharger is not the right choice and the Taxi has dual continuously variable valve timing.

To give an idea about trying to match the torque to weight of the F6. Even if the Alfa was down to 1250kgs @ 2000rpm it would still need to dish out 400Nm of oomph.

Or 57.5%/170Nm more torque @ 2000rpm than standard. 

[four90s]

Come on Duk.....It's good to have a dream.

Regards
Steve
Adelaide.

[jazig.k]

ITT - Why the F6 is better and I won't ever finish the Alfa.

[Colin Edwards]

Fitting a 100mm, 101mm or 103mm big bore kit would not mean re-inventing the wheel and probably give you the torque you want.  The horsepower and long term reliability might be an expensive challenge however!

Having played around with race kart engines for while their certainly are engineering issues to be resolved with regard to fitting bigger cylinders / liners into an existing block of alloy.  The mechanical challenge of dealing with cavitation and resultant erosion of wet liners up near the combustion chamber is one thing as is the thermodynamic challenge of conducting away all that additional heat absorbed into the greater surface area of the larger diameter bores.

Given the 3.2 JTS engine is based on a RWD / North South powered car could the GMH / Holden sourced block be rotated 90 degrees and dropped into the chassis?  In standard tune it puts out 260 HP and loads of torque thanks to it direct injection.  With no CATS and a bit of re-mapping 280 < 290 HP should be achievable.  Plus the engine is about 160kg.

All with standard and very easy to source bits!  The 3.2 JTS in a car 300kg lighter than a 159 might be something!!!

[Duk]

ITT - Why the F6 is better and I won't ever finish the Alfa.

It's about time you acknowledge the superiority of the F6. 
As for finishing the Alfa, yeah I have a pretty bad track record with it, but I will finish it when I settle on a plan.

Fitting a 100mm, 101mm or 103mm big bore kit would not mean re-inventing the wheel and probably give you the torque you want.  The horsepower and long term reliability might be an expensive challenge however!

Having played around with race kart engines for while their certainly are engineering issues to be resolved with regard to fitting bigger cylinders / liners into an existing block of alloy.  The mechanical challenge of dealing with cavitation and resultant erosion of wet liners up near the combustion chamber is one thing as is the thermodynamic challenge of conducting away all that additional heat absorbed into the greater surface area of the larger diameter bores.

Given the 3.2 JTS engine is based on a RWD / North South powered car could the GMH / Holden sourced block be rotated 90 degrees and dropped into the chassis?  In standard tune it puts out 260 HP and loads of torque thanks to it direct injection.  With no CATS and a bit of re-mapping 280 < 290 HP should be achievable.  Plus the engine is about 160kg.

All with standard and very easy to source bits!  The 3.2 JTS in a car 300kg lighter than a 159 might be something!!!

There won't be any engine conversions.
Even if I did entertain the idea, I would just use a Commodore 3.6 engine.

[jazig.k]

Twin compound turbo with supercharger setup.

[Duk]

Twin compound turbo with supercharger setup.

On a 7 litre LS?
With nitros?
And a 2 speed Powergluide?

I was doing some rough number crunching and added up some guesstimated weight reduction figures.
They were all guesses, but with a bunch of carbon fiber panels (bonnet, boot lid, front guards, front and rear bumpers) and tailshaft, fabricated suspension arms, coil springs instead of torsion bars, no power steering, no brake booster and cross over, even things like the fabricated extractors, I guessed about 75-80kg of weight removal.
But that didn't allow for the new cabling for the boot mounted battery, the chassis reinforcement, the bigger brakes or the larger exhaust. The Volvo calipers will be replaced with 4 piston RX7 calipers.