Classic Alfa Forums

My toy, enjoy.

I bet that's fun

Yes, and this is what hides under the plenum.

25psi on street fuel.

Exterior.

Very nice I like that a lot

Holy moley...

Nice - what sort of power/torque does it produce?

400bhp ish?

great to see the twincharge on here.
This car is my inspiration to keep plugging away at my little projects.
Did'nt know you had put the polished cam cover on, looks good.

hiya Dave,

You are the inspirational one with your attention to detail!

Yes, the car puts out about 400hp at the crank, at a guess. I have had it on the dyno in the early days, and it made 190KW@the wheels on 26psi. Since then I have added a bypass valve which I actuate at 3500rpm and a much much better inter cooler setup. This improved top end considerably as the sc14 supercharger is a twin lobe basic charger with a paltry efficiency rating, where as the GT35/40 turbo running 1.06 rear is 76percent efficient at the 26psi I run on this engine.

That's on a stock head and stock liners, so lots of scope for improvement.
I also have water meth injection, but I am yet to turn it on.

I am now building version 2 with a target of 700hp, one day I would like to take it to Bonneville..that is the dream. This engine is based on a twinspark...with anything but stock head. It's a lofty target, but as they say, aim high, and if you just miss the target, the result is still impressive.

This video gives an idea of how the boost comes on relative to load and revs.

https://www.youtube.com/watch?v=40NBriAge-E

As you can see, I get instant boost from the supercharger, but with bypass in place, should really change the pulley so 6 becomes 15, whihc in turn supplies more exhaust gas to the turbo, getting it spooled earlier again.

Got a spare few hours? Have a read of the build. Leave a comment if you like it.


http://www.alfabb.com/bb/forums/engine- ... oject.html

http://www.alfabb.com/bb/forums/engine- ... rm-27.html

http://www.alfabb.com/bb/forums/engine- ... 700hp.html

just read the first 2 of 80 odd pages, will take me a few nights to catch up but i will, great stuff

G'day. I've not been on here on a while. Lots of projects going on in my shed at the moment. You can follow them via Instagram where I will be kicking off my new twincharge Alfa project.

Instagram name: instagram.com/barrengermichael

Follow me and share the ride!

Update on this thread:

The Alfetta twincharge was on the dyno after the bypass valve was installed. I can confirm it made 320hp at the wheels at 5500rpm. That was up from 252 rear wheel hp before bypass install. Before the swap, I ran my homebuilt spreadsheet on the numbers which suggested I could gain 70hp by bypassing the supercharger. That was at the engine, so I would say that the bypass made more hp that I expected. I put this down to being way off the effiency island of the sc14 supercharger at 250wheel hp. Looking at others experiences with this supercharger suggests 150kw is really the max.

At this hp the Alfetta does feel properly quick. I would say that with the sc charger set at 6psi only, down low this does not set my world on fire. Now that I bypass it is feasible to fun a 10 to 15psi pulley...since I won't have compound boost ceiling issue with bypass running. This and E85 will be the last 2 mods the car receives. That's as much as I dare run on the factory liners..which are pronged and in welded only. I am very impressed with the bullet proof nature of the fantastic Alfa Romeo 4 cylinder. 8 valves only and putting much newer engines to shame...sort of haha!

Mike