Upgrade horsepower on alfetta 2L

[Neil Choi]

Stefan

Are you quoting 160-165 bhp and then wanting 170-180 bhp from a normally aspirated Alfetta 2L, at the engine or at the wheels?  Just to clarify what you and everyone are quoting, because figures are different, there is about 30% difference (lost) going from engine to wheel.

Hope you can clarify because I like to know.

Neil

[BradGTV]

there is about 30% difference (lost) going from engine to wheel.

can anyone else confirm 30% ? ive heard it was around 17-20% drivetrain loss?

[Paul Gulliver]

Brad,

I think there are a lot of variables in this equation . I think the truth is somewhere in the middle. ( maybe  around 20% on a good day) I remember reading some road tests on the Alfa 166 and the difference between what was quoted ( at the fly wheel) and what was actually achieved on the dyno (at the wheels) was something like a 25 - 30% loss.  

Here's some figures from a recent club dyno day at Beninca's. If you have a look there at not to many  2 litre rear wheel drives achieving anything like "an easy 160 bhp"

 http://www.alfaclubvic.org.au/forum/index.php?topic=5540.0

Brad i think i have also read that you are doing a twin spark conversion on your GTV. I also have an alfetta  twin spark GTV . If you read the road tests on an  8 valve twin spark they are quoted at 150 bhp ( at the flywheel). Mine after a bit of fettling from Beninca's achieved 120 bhp at the wheels  (20% loss) . Beninca's have advised this is about as much as you can expect without opening the engine and spending spending a lot of money  

[Paul Gulliver]

Bump,

Stefan, just as a bit of a reality check on what achieving those sort of hp numbers is going to cost, have a read of this thread from last year paying particular attention to the words from Vin Sharp.


http://www.alfaclubvic.org.au/forum/index.php?topic=7305.msg43532#msg43532

To quote Beatle Bayly from earlier in the thread  Cheap, Reliable, Power?  Pick any two at the expense of the third

[Neil Choi]

Brad, you are quite right, powertrain loss is around 15-20%, I do remember seeing a couple of 3.2L GTA on a particular dyno, quoted 250 bhp in specs (presume at the engine), on the day - ~200 bhp (at the wheels), 20% loss.

Which was leading to Stefan's aim and quote, I was confused on and wanted clarification on what he was aiming for.

I along with a few (many in fact) others also wants 170-180 bhp (atw), even an easy 160-165 bhp (atw) will do me too and road drivable.

All was leading to Paul's comments which is what I had believed along with a few others.

Stefan, let us know what your plans are and how you go.

Cheers
Neil

[Neil Choi]

One rule of thumb someone told me was for a car with quoted kW, change units to bhp that's roughly (+/- 10 bhp) the power at the wheel.

eg 3.2L GTA 184 kW (245 bhp), 200 bhp atw, Alfetta 2L 96 kW (128 bhp), 90-100 bhp atw

Sounds right??  And of course one dyno isn't same as the next.

[Duk]

Rather than getting hung up on chassis dyno to engine power figure conversions, how about just using the dyno for what it's designed for, a tuning tool.
If you start with the standard car, run that on the dyno and save the computer plot. Modify and tune (using the dyno for feedback) and then do another run (assuming the dyno's calibration hasn't changed much and the weather is similar). Overlay the 2 computer plots and show to the world if you think you need to. The percentage differences show a lot of where it's at. You won't see part throttle behavior unless you do a whole bunch of runs and log and compare them. Hmmmmmmmm, 3D dyno plots, that would show some real truths  .

[hmd]

Stefan,

I have that book on my bedside table, I have also a book on nuclear physics and if my solar panels don't produce enough power I might try some home brew reactor 

Jokes aside, you will need cams, head works, high comp pistons, extractors, webbers
then add on the 'while you are there' items... cam chains, lighten rods, clutch, flywheel .... it will be around 10K minimu.

This will give you somewhere between 120-130 bhp at the wheels on Beninca's dyno.

Neil has had many configuration on 2L engine in various development stages he should know.

[ItalCarGuy]

You could always wait for Greg Gordon in the US to start selling his 2L supercharging kit...

http://www.hiperformancestore.com/superchargerkit.htm

[Duk]

You could always wait for Greg Gordon in the US to start selling his 2L supercharging kit...

http://www.hiperformancestore.com/superchargerkit.htm

Greg's 4 cylinder supercharger kit is for the fuel injected engine.

[ItalCarGuy]

Greg's 4 cylinder supercharger kit is for the fuel injected engine.
[/quote]

Ahh, I see. Here is another supercharging option   currently for sale in South Africa!

[Beatle]

I wonder how long that drive belt would last at full song..............................

[Paul Gulliver]

I must be getting old , but really , why would you bother . If your going to get into a " hp pissing competition " i dont think you would start with an alfa. On the assumption this thing lives somewhere other than on a dyno, the next sensible upgrade for this car would be a periscope so see where and how you are going.

[ItalCarGuy]

You wouldn't want to drive it in the rain either. I've never understood the protruding engine thing. Only suitable for the drags I would think.

[Beatle]

I must be getting old , but really , why would you bother . If your going to get into a " hp pissing competition " i dont think you would start with an alfa.

I have to agree Paul, but to each his own.

I spent a lot of time solo behind the wheel of my first Alfetta, on empty mountain roads on the limit, and I scared myself enough times to be glad I DIDN'T have any extra power.......

Years ago I decided the best response when asked "How much power does it have" was "I wouldn't have a clue....."