Twin Spark max power curiosity

[MD]

Does anyone out there in the known universe know factually what the maximum naturally aspirated
output bhp (flywheel) and torque figures that have reliably been achieved for the Alfa 2 litre twin spark engine?

I am aware of Jim Steck's work.

Any links to info is much appreciated.

[BradGTV]

alfaholics and ahm have produced some pretty high numbers around 220-230hp, but i think the beneica's have got about 250hp?

[Paul Gulliver]

MD,

Beninca's Twin Spark  = 230 bhp @ 7300rpm.

Have a read of this

http://www.autospeed.com.au/cms/A_0717/article.html

Gully

[MD]

Interesting read indeed. Pitty no mention is made of the amount of torque the engine makes and over what rpm range.Whilst 230bhp seems credible with dry sump and mono sleeve, after decades of evolution that is only 10 bhp above the auto delta engine running carburettors. Perhaps the torque figures tel another story. It must be incredibly difficult to do much better.

I undestand that Vin Sharp is working on producing a 240 bhp Norde engine or is this a reality already?

Impressive attention to detail and a holistic preparation of the entire car as it should be.

Thanks Paul.

[vin sharp]

Interesting read indeed. Pitty no mention is made of the amount of torque the engine makes and over what rpm range.Whilst 230bhp seems credible with dry sump and mono sleeve, after decades of evolution that is only 10 bhp above the auto delta engine running carburettors. Perhaps the torque figures tel another story. It must be incredibly difficult to do much better.

I undestand that Vin Sharp is working on producing a 240 bhp Norde engine or is this a reality already?

Impressive attention to detail and a holistic preparation of the entire car as it should be.

Thanks Paul.

Vin Sharp wishes he was working on a 240hp Nord, but I don't think so.......have had a couple of single plug 2lts on carbs read 220hp+ @7500, (165ftlbs @5400) on Tillys engine dyno in Sydney, which in turn have shown 170+ at the wheels on Benincas rolling road. As I recall Joe Beninca saying their 230 engine hp showed about 185+ on the rolling road, so a little discrepancy there; I suspect Benincas 230hp is actually a touch conservative, in relative terms.
These are held, steady-state readings. Not pull and snatch inertia-peaked readings; the difference is like placing a weight on a scale and measuring as opposed to dropping it and recording the highest deflection of the needle.
I would suggest that ultimately, from what I have seen of others peoples work and that done of my own, that a T'spark would probably have an upper limit of approaching 240hp, with all the latest EFI technology all the best engine hardware. An equivalent Nord would be perhaps 6-8 behind due to combustion chamber shape. A Nord still has the highest 8v port flow rate that I have ever measured on my Superflow.
I have never seen any of the O/seas engines in operation, so can't really say. However I have supplied some stuff to a guy in Norway who is the man to beat in Alfas up there. He runs against various UK powered cars and wins with what I would consider very much club level here.......there is also another guy that just paid AUD32,000 for a 200hp Nord without ancilliaries from UK; one would hope they're draught horses.......and bloody big ones at that!
Cheers,
Vin.

[MD]

Thanks for chiming in Vin. I hope your wish comes true..

That settles it. I now know the power ceiling so to speak.

For an amatuer mechanic like me, it was hard enough to get 200 bhp/160ft/lbs flywheel and that's with 145cfm @12.7mm lift, 47mm intake valves,46mm TB's, 12.5:1 CR, Avgas,2009cc bore,CP forged pistons, Carello rods, 12.7mm lift cams, Motec ECU, light flywheel, tuned headers and secondaries with matched intakes, wet sump.

Never got to develop this engine further for complex reasons but I suppose, a dry sump would have been the next step and working out why the power fell off @ 7200 but I think I know why already. I didn't make enough use of the flow for a start..

....one major issue with these and Norde engines (apart from the single wet sleeve issue) is the mass of the crankshaft. Alfa has made a beautiful and tough crankshaft and it's why this part of an Alfa engine hardly ever gives any problems. Unfortunatley it will hold up half the Sydney harbour bridge due to its mass and getting this down and keeping the balance is no easy task. This has to be a limiting factor as well. Comparing say a Nissan SR20 crankshaft to the mass of the Alfa one is a real eye opener given that they are both road engines.

I have never seen anything where someone has remade this crankshaft for a dedicated race engine.

I think  I need to engage brain box on how to loose weight instead of chasing more power that isn't there..

[Duk]

Over the years I've heard about people removing serious mass from the FIAT 2 litre crank, maybe sniff around and see if you can find pictures or figures?

[pancho]

speaking of all things TS, does anyone know where I can get a set of stainless or similar lightweight TS valves made up in Melbourne?

I need a set of 8mm x 46mm TS valves machined up as the US parts supplier I use are talking months away for thier ones and I am advised not to go to 47mm.

[Tastarga]

Try Eddie Woods at "The Head Stud" in Moorabbin - 31 Capella Cres - Ph 9553 2517.

He made up a set of staiinless valves (as well as repairing a damaged alloy head) for my Targa car (Ferrari) in 1995 - still going strong, 70000km later, including 6 Targas, 5 Classic Adelaides etc.

[pancho]

Thanks you very much for that tastarga, I spoke to Eddie today, very helpful and informative.

[MD]

Hey Pancho.

I am advised not to go to 47mm.

Who said that and why?

BTW the total mass of the valve and the shape are of substantial importance. Have you factored that in?

[pancho]

Hi MD,

a. From my very well respected alfa engine builder - for longevity 46mm should be enough and 47 may not generate sufficient gains to warrant being that extreeme. I am told Port velocity at 46 should also be more than sufficient for a road engine.

b. I am merely going with basically what currently available out there, the valve makers recommendations and also the cost of the component - I am also consulting all this info with the engine builder and machining workshop who have the flow bench.. 8mm x 46mm is the size - Spruell gets some ss valves that they claim are lighter than stock http://www.spruellmotorsport.com/valve-twinspark-special-oversize-intake-8x46mm-p-3970.html

We are going with standard exh valves.

The above being said I will get another TS head perhaps a 155 TS and do some experimentation to see if we can get more power out of it using higher lift, longer duration cams and larger valves - but I'm no engine builder - just an enthusiast being guided by informing myself and also being guided by professionals. The bottom end is bullet proof and will support at least 8k (but this is a mainly a road engine).

I am though open to listening to all sides of people experiences though. I have seen you also have a TS engine you've been working on for some time now in the GTV - how have you found the tuning and ease or difficulty extraction of power out of the 75 TS ?

I am also in the midst of reading this awesome thread from many moons ago - started by you actually!!

http://alfagtv6.com/phpBB3/viewtopic.php?f=21&t=622

[MD]

Oh I see. A road engine. I naturally assumed a race engine in the making your post being here in the "max power' area. Ok that sounds very sensible in that case and I support your logic.

I will just say this much:

Getting around 180-185bhp from any Alfa 2 litre engine is relativelystraight forward and you could loosely call it a linear progression for effort and bucks.For a road engine, you should stop here to get value for money.

The next 25bhp is more like logarithmic both in effort and moolla.

Getting above 100bhp per litre for these engines, belongs to tuners who have a missing chromosome,they are related to Albert E and have in house flow benches and engine dynos..