GTV6 Carby Conversion

[shane wescott]

Hi Guys

Might sound like a dumb one (happy to ask dumb things). Has anyone, could anyone convert a GTV6 from injection to a carby setup. Is there a kit ??

Of course this would all have to be done with the relevent emmission regulations being met, but just curious if it would be possible.

I must confess I know bugger all about, and am quite scared of fuel injection and car computers (funny seeing I work in the IT industry), so that is the angle for my question.

Thanks in advance for replies.

Catch ya

Shane

[Mat Francis]

correct me if i'm wrong, but didnt the 200 or so 3L south african gtv6's have triple downdraft webers?

i wouldnt say dumb shane, i reckon the noise of such a device would be unreal. i would definately be a fan of such a conversion.

[shane wescott]

Yes the sound of a GTV6 with webers - could there possibly be anything better.

First thing to do after the conversion would be to remove the stereo, you'd never use it again, and forget about a hands free kit, I have enough trouble already hearing the conversation :-)  --but I love it:-)

Catch ya

Shane

[Sheldon McIntosh]

The Alfa 6 had six dellortos on the 2.5 V6 from memory.  That'd be fun to balance.

Bonnet may be too low on the GTV though? 

Yeah, good idea, go for it.

[Alan Hopla]

Shane,

Matt and Sheldon are on the money here.

There were some 3.0 GTV-6 built in South Africa.
The August 2008 edition of Octane had a write up on one.
In that they talk of the conversion to six single choke down draft Dellorttos.

The Alfa 6 is also described as having six Dellorttos, and in some other places three twin chokes.
Interestingly a damaged Alfa 6 was auctioned at Fowles in Melbourne this week.

[JOHN G]

Hey Shane
I have two carby conversions.
I prefer the carby sound compared with fuel injection.
However,there are positives and negatives to both.
John.

[Mat Francis]

any photos available john? or better yet videos of these beats? i would LOVE to see these, let alone hear them...

[Paul Newby]

I have a factory Dellorto manual at home. It doesn't go into a lot of detail (say compared to the Veloce/Powertune book) but it covers all of the Dellorto models including the single choke and triple choke models.

IIRC the South African GTV6 had an Autodelta developed 3.0 which has a different bore and stroke to the later Alfa designed 3.0 and ran the six single Dellortos. I think that only the first series Alfa 6 ran on carbs and then either with 6 singles or 2 triples. (I thought it was the former, but the later is listed for the Alfa 6.)

I believe that the Dellortos are a nightmare to tune and you are probably better off with sticking with the Bosch injection, which isn't as complicated as later Bosch Motronic systems seen on 75s and 164s. 

[Scott Farquharson]

Mad if you want to go to carbies - If you really wanted to replace the Bosch then go to an aftermarket ECU (Autronic, Haltech, Motec etc) plenty of this has been done and the result would be far better than carby.  Autronic is proven with many GTV6's done - 12 and 24 valves. 

[alfagtv58]

Or even go with the Bosch Jetronic off the 164's instead of the Motronic.

[JOHN G]

1st Pic South African/Autodelta 3.0 motor, now a improved 3.3 AHMOTORSPORT 250 BHP (ATW).

2nd Pic RJR RACING 11.85 3.0 running 50mm SK carbs 300BHP+ (at the crank) to go into one of my Grand Prix's.

[vin sharp]

The Bosch system as on the gtv6 is one the simplest and reasonably efficient and reliable sytems out there, certainly no need to worry about reliability issues if things are maintained in a reasonable condition......
F.I. will deliver a far superior fuel mixture right across the range that carbs can never do, so the power, economy and lack of wear of engine internals cannot be matched by carbs.
If one was to change to carb for some reason (F.I. runners and plenum not big enough), then downdraught, individual throttle per cylinder is the only half sensible way to approach it as this at least maintains some of the direct delivery of fuel to the inlet valve area. Any change of direction required by an air/fuel mixture into the valve area spells loss of mixture volume, velocity and vapour suspension quality and increased pumping losses. 
Most engines designed using F.I. will never be able to reach their maximum potential with carbs because the port angles and shapes were never meant to carry air/fuel (only air) in the first place. This doesn't mean to say that you can't make something reasonably useable, but it will never be anywhere near as good as it could. 
Individual cylinder butterflies with either carbs or F.I. will give the advantage of separating the intake tracts so the a hot cam will idle and drive like a stock one and increase throttle response. 

[shane wescott]

Great info from all - love the photos.

Simple and reliable - i like the sound of that - I will just have to do some learning so I am at least basically familiar with how it all works.

I'll just have to buy another alfa with Webers :-) (an excuse to buy another car Yeah)

I am assuming the GTV6 and 75 Twin Spark have different FI systems, is the 75TS simple and relaible as well.

CAtch ya

Shane