ALFAGTV6.COM

FLETCH · Post by **FLETCH** » Mon May 15, 2006 3:54 am

Guy's,
what effect does the lengthening or shortening,and increasing the size of the intake runners have ?
Reason i ask is i am trying to decide what to do with the 3l i am putting in my gtv6,the 3l came from a 164,and has the longer rounded runners. as you know the plenum and runners need some modification to fit in a gtv6 engine bay.
i was thinking of turning the runners around 180 degrees and run the plenum done the passengers side head(RHD CAR).But the throttle body and the end of the plenum interfere with the cam pulley.so to get around this i thought about making the runners "run" further down the rocker cover(extend them about 100mm).
or put the plenum on the passengers side as above but instead of extending the runners,cut the end of the plenum and weld it back on at a different angle to clear the cam wheel .
i'll try to post some pic's to help show what i mean .
any help please

CHEERS ALL
FLETCH....

FLETCH · Post by **FLETCH** » Mon May 15, 2006 4:08 am

OK ,2nd pic showing rough position of plenum,and amount of extra length needed on runners,and 1st pic showing how the throttle body interferes with cam wheel.

Jose_76 · Post by **Jose_76** » Mon May 15, 2006 4:50 am

Why don't you use the GTV6's runners and plennum? A friend of mine did so and looks stock.

Daniel · Post by **Daniel** » Mon May 15, 2006 12:52 pm

There's an old thread somewhere on this but I cant remember if it was the old forum site. If my merory serves correctly (plenty of alcohol to preserve it

) the GTV6 / 75 runners are tuned for around 9000 rpm and the 164 runners for more like 7500 rpm.
I am on my 2nd 164 engine to GTV conversion (1 x 12v and now my car getting the 24v) and I have also seen MD's 164 conversion more than a few times.
Imho modifying the 164 plenum to run the throttle off the side of the plenum is the way to go. I used this as an opportunity to increase the volume a little. Bonus is that it all fits under a stock 2.0 bonnet.
I had (and occasionally still do) consered running twin plenums and throttles but that just stuffed the idea of retaining the standard Motronic setup.

MD · Post by MD » Mon May 15, 2006 2:56 pm

Hey FLETCH,

If you wanna re-invent the wheel, go for it.
If you'd rarther spend the time chasing crumpet, why not give this (or the like) approach ?

iachella · Post by **iachella** » Tue May 16, 2006 6:26 am

I believe lengthening the runners moves torque to a lower rpm for better pickup. Widening them increases the air to the engine, so you can get more power if you get the fuel right after that. But it may not be much if you don't get bigger valves.

Whether Alfa has the optimal length already, I don't know. But you probably won't change anything too much by your mod. Give it a try, I say.

FLETCH · Post by **FLETCH** » Thu May 18, 2006 2:58 am

MD and Daniel,have you guy's got anymore pic's of those plenums,some from different angles ?
cheers

Intake runners,length and diamater!!