ALFAGTV6.COM

This is what I did. 164 intake. but I moved the butterfly to the front.
and made it look as stock as I could.
if I ever go boosted it will plumb right to the inter cooler

MD wrote:Darryl,

That set up is Daniel's street/race project in the making. It is a custom made pedal box. As you can see, no booster. He is a pretty busy guy and if he doesn't get around to seeing this post, send him a PM. I am sure he wil be happy to tell you about it and possibly even make you one..He made mine,for a special application that needed to clear a custom plenum on the race car!
Works great.

Thanks MD
Daniel has taken time out to explain the brake set up.

What you think of this design .http://www.youtube.com/watch?v=eiy16rVm1IQ

Beaten to the punch
I love it! I believe it address's many requirements of a good manifold design while fitting under the bonnet.
Seeing as how it looks like you guys have lots of the good stuff, did you do individual exhaust temp measuring of AFR measuring when tuning?

Duk, You might be beaten to the punch BUT this does not fit under a standard bonnet only a modified 3.0 L bonnet so its back to the drawing board for me in my class as we have to run exact silhoette of original body. Also trying to keep in some budget.
I looking at 166(45mm) runners again into modified 166/164 plenum leading symetrically into the throttle body. Now big question is what size TB. I have seen two tuning companies here and in uk who do big bore conversion using larger diameter TB from one of the Ferrari range. Both claim exta 10kw on the setup in the Alfa GT, GTA - then again these are big bores.
So Duk, dan, Md etc what do you think would be optimal size on the 3.0 24v.( into the 116 body) It seems strange that the standard gtv 2.5 TB has the same ID as a GTA. Thoughts ??

Maxing out a 70mm Throttle? Congrats, sounds like 500Hp or something.

I was thinking about this style of manifold design and tripped over this picture in my web travels. Basically a set of equal length exstractors (inductors or 'inducors' ) for an inlet manifold.
To me it makes logical sence, air traveling towards the inlet runners should have more natural momentum rather than being forced to make 90 degree turns to try and find it's way into the inlet runner. Each runner is in the same relationship with the plenum chamber and throttle body. I'm seeing an imroved design over a conventional log style plenum, but this system is hardly used, tho I do recal seeing a similar approach on a Mazda B6 or BP 4 cylinder, too.
Purely a cost thing? Lack of real world bennefit?

What is the benefit of longer intake runners and bigger plenum. How do you guys know what is the perfect size and lenth for each setup.
Arent individual TBs like the AHM from UK more efficient to gain power?

individual TBs don't give you any power per se, they make it possible to run camshafts with longer duration/more overlap. If you have a plenum behind a single TB and wild cams the plenum is likely to fill up with EGR (exhaust gas), that needs to be evacuated before you can fill it with fresh air when you open the throttle and it evacuates through the engine of course = bad throttle response. Also, the "ideal plenum size" is really infinite large but if you have a single TB the response will be worse with a larger plenum. With individual TBs you can use the atmosphere as your plenum = infinite.
You can calculate runner length and diameter with formulas but in the end the dyno will give you the truth so if you really want every last percent you need to play around on the dyno with different configurations.

I would like to know if the Autodelta 235hp GTV6s of ETCC had the induction sistem modified. From pictures I´ve seen it seems it were unmodified.
Anyone has info of this motors? or the ones that Alan Jones GTV6 used?

What you see is not what you get and this stuff of intake plenums produces outcomes that can be unexpected.

For instance, the filtered induction set up with the plenum in a static situation on the engine dyno produce 15hp less than when the car was on the move on the track. Both the plenum and the socks over the TB's produced the same power on the move where the socks setup now lived in a much larger virtual plenum consisting of the inner guard and bonnet.

you figure it out...

Nice setup MD. Is that plennum based on Canister filter casting the late 105s and alfettas had?
I assume you're basing the hp on the move on data logging down the straight, and the open socked setup made 15hp more on the dyno?

Where was the intake temp probe for the dyno mounted for each run?

Yeah hi Buddy,

The filter for the plenum is not the 105 type. It is a card filter and sits in a VL Commodre black box with its arse cut out and facing direcly into the wind behind the dummy front rhs headlight. On the move this would create a positive pressure in the plenum but not sufficient enough to call it any form of supercharging. The air temp sensor was fitted to the filter box.

For clarity, the fully filtered +plenum made the same horsepower based on lap times as did the no plenum and red socks with segregated hot/cold engine bay zones.The temp sensor was in the same position for both to all intent and purpose.

The difference in what I am saying is that in a static situation with the engine on the engine dyno and using the plenum and filter, it made 15hp less ie. on the move = +15hp at standstill = 15 less.(same set up).

So when it comes to testing your design, you may incounter some quirks is what I am saying.

Hey Kevin, note the large diameter pulley on the alternator.

Incidentally, that single coil on the inner guard is there only to fire the Veglia tacho I was using at the time. It didn't want to know anything else. Both are now history.

MD,

I wonder if the -15bhp is due to the lack of some ram air during the static dyno test?

Which setup produced more power on the dyno, the ITB or the plenum?

Zamani

In some respects you are right but not entirely. I believe the increase in power for the same set up on the move is due to plenum internal effects of the induction air pulses being scrambled and not allowing resonant internal waveforms to impede the inflow. (sort of like a back pressure but at the intake instead of at the exhaust. Wanna go nuts? read up on Helmholtz resonators)

As for your second question, the induction system on this engine uses the same 4 throttle body set up for all combinations. What changes is either the fitting of socks or a plenum with filtered intake.

I hope that clears it up for you.