ALFAGTV6.COM

MALDI · Post by **MALDI** » Tue Mar 11, 2008 5:07 am

Check this out, Alfa's development of a high efficiency engine from the Busso V6.

http://www.gtv6-156gta.be/LaGTV6present ... rmodulaire

Google automatically translated text:

"Designed technically very interesting, but which has never been known for mass production: the V6 configuration "modular engine"! If today it seems only natural that all manufacturers are interested in the production of engines known as "clean", which pollute less and consume less, it must be remembered that this concern is not new . In early 1980, Alfa Romeo had developed a system called "modular engine" that the firm had applied to the 4-cylinder engine (a dozen taxis rolled with 2 L 4-cylinder leading to a decline in consumption on the order of 15%), but especially at 2.5 V6. It is a design in which an engine turbo is grafted onto a bench of cylinders, the other being fed bench cascade by exhaust gases from 1 bench! The V6 develops and configured the power of 192 hp at 5800 rpm with a maximum torque of 26 kgm at 4500 rpm, an increase of around 20%. The engine is capable of running most of the time on his bench 1st cylinders and may even reach a speed of 162 km / h in only récourant only one bench. All this is accompanied by a reduction in consumption of 29%! The 1st bench cylinder (4-5-6) is fed by a turbo-compressor powered by fresh air and subjected to a compression ratio of 12:1 (to recall the compression ratio is 9:1 in all cylinders the V6 atomosphérique the GTV6). The 2nd bench (cylinder 1-2-3) is financed by gazs exhaust from 1 bench with an intercooler (for cooling) and with a compression ratio of 8,3:1."

The exhaust of one bank powers the turbo which feeds the other bank.

slyalfa · Post by **slyalfa** » Wed Mar 19, 2008 4:35 pm

the pic makes it clear.

but I do not know why you would want to turbo only ½ of the motor..

seems like it would run strange too. stong pop, weak pop, strong pop,weak pop, etc
just seems like it would start to shake.

I see the gas saving of shuting down ½. the caddy did somthing like that too.

sh0rtlife · Post by **sh0rtlife** » Wed Mar 19, 2008 4:55 pm

the theory behind it is that the turbo presure on one side is FORCING the pistons on there way up very hard....its a nice theory but i dont think id trust it in the long run

much like the caddy 4-6-8 that sucked!

MALDI · Post by **MALDI** » Thu Mar 20, 2008 5:42 am

It runs on the normally-aspirated cylinder bank in low power situations (at idle, highway cruising, etc), then when you want power it sends fuel to turbo charged bank of cylinders.

Notice that it has a knock sensor, something that was thought to be impossible to implement on the Busso V6.

Mats · Post by **Mats** » Thu Mar 20, 2008 8:14 am

I don't get it. There is a turbo on the non-turboed side? so you runt it with restriction when you don't need power and then power up the other side when you need boost? That sounds backwards...

Why would it be impossible to have knock sensors on the V6? Lots of solid lifter cars have it (including the 75 T).

MALDI · Post by **MALDI** » Thu Mar 20, 2008 9:22 am

Mats wrote:I don't get it. There is a turbo on the non-turboed side? so you runt it with restriction when you don't need power and then power up the other side when you need boost? That sounds backwards...

Well, not reading Italian or Dutch I can only piece the story together. I guess you could run it on the three turbo charged cylinders without boost (because the normally aspirated cylinders would be off and they power the turbo) and then for power add fuel to the normally aspirated cylnders to get their power as well as an extra kick from the turbo for the forced -induction cylinders. But to me that seems backwards...

Anyone out there actually able to read the two articles on the site given in the first post???

Mats wrote:Why would it be impossible to have knock sensors on the V6? Lots of solid lifter cars have it (including the 75 T).

I was under the impression that the valve train noise from the push rods prevents the use of a knock sensor on the Busso V6, but I am not certain.

Maurizio · Post by **Maurizio** » Thu Mar 20, 2008 10:58 am

Italian or Dutch

This is no Dutch or the spelling suddenly changed

ps: It is French

Edit: Aaah, I see, on the bottom of the page there is a dutch press paper from '87.

ok ask:

They run a NA side with 12:1 CR
The other bank runs a 8.3:1 CR with a garrett T2

When cruising the car only runs on the na bank, the other bank only gets air pumped in from the turbo, to reduce pump losses. The turbo is powered by the exhaust gas of the na bank.

The idea behind it was that during cruising, the efficiency of an engine goes down due to pump losses and the lesser degree of filling of the combustion chamber.

On the test bench they had:
- 192 hp @ 5800 rpm
- 26 Kgm @ 4500 rpm and a 29% fuel saving

wrt a na 2.5 V6 with 165 hp and 22 Kgm

hmmm sounds like a fun engine to work on.... both banks have their own electronics

MALDI · Post by **MALDI** » Thu Mar 20, 2008 11:31 am

Maurizio wrote:ps: It is French

We Americans prefer to ignore the French.

MALDI · Post by **MALDI** » Thu Mar 20, 2008 11:36 am

Maurizio, thanks for the translation! It is an innovative idea but I'm curious how it drove having unbalanced cylinders? Also, I wonder, does the car still exist? Perhaps in the Arese Museum Collection (but not on display) or rotting in some corner of a Milan warehouse.

Maurizio · Post by **Maurizio** » Thu Mar 20, 2008 11:52 am

They actually calculated that the fuel savings could go up to 34% if they installed single throttle bodies on each cylinder of the NA bank.

In the paper is a phrase that there is a prototype alfa 90 with this engine.
And that they are currently (during the write down of the article

) testing engine in several cars.

slyalfa · Post by **slyalfa** » Thu Mar 20, 2008 5:48 pm

OK I see now so the fule is cut on the boost side but it gets full boost all the time WOT
so the boost pushes the pistons down on the intake stroke. if the valves could change it would work even better. say no compression stroke. just push down then open the exit valve on the way up. I would say have matches turbos on both sides and normal CR on both sides. or a bigger single turbo. and a bypass system to run the boost on both sides when you stomp on it.

Yes I want my cake and to eat it too...

Greg Gordon · Post by **Greg Gordon** » Thu Mar 20, 2008 9:18 pm

I can't read the text, but I think I understand the reasoning behind this idea, and it could work.

This is an attempt to get around the problems of variations in effective compression ratios.

Most of us understand that under boost the cylinder's effective compression ratio is higher than the mechanical compression ratio because of the extra air in the cylinder. What's often overlooked is the opposite issue. When cruising at part throttle, off boost the effective compression ratio is well below the mechanical ratio due to the low manifold pressure resulting from the throttle blockage. This is inefficient, but we put up with it because we need to aviod knock at higher manifold pressures.

This engine runs three cylinders with very high compression normally aspirated for off boost fuel economy. Of course the compression in the normally aspirated cylinders is too high for boost so they only boost the other side. That other side is very inefficient during off boost driving so they shut it down under those conditions.

This idea is probably sound in theory, but I would do it differently.

Greg Gordon,
www.hiperformancestore.com

Mats · Post by **Mats** » Fri Mar 21, 2008 3:03 am

MALDI wrote:
Maurizio wrote:ps: It is French
We Americans prefer to ignore the French.

That is obviously a mistake on your behalf.

MALDI · Post by **MALDI** » Fri Mar 21, 2008 4:29 am

Greg, would you guess that the engine would have a 'rough' or 'unbalanced' feel to it because in many (most? all?) situations it would have different amounts of fuel in the cylinders of one bank versus the other and/or different peak pressures in the cylinders of one bank versus the other?

Mats, it is a pun, French being both a people and a language...

Mats · Post by **Mats** » Fri Mar 21, 2008 4:57 am

ah, got it.

Saab did make a v6 with half the engine boosted, or was it half the engine spinning a turbo? Anyway, it was deemed sucky by all and now they use both banks to feed the turbo.

High efficiency V6