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Hi All,

Has anyone ever put the 164 12V V6 inlet manifold on a flow bench? If yes, what were the results?

Can anyone tell me what the internal diameter (ID) of the inlet runner pipes are? Is it the same at both ends?

I am trying to work out if the inlet runners with a custom plenum (larger & tb facing forward) would work on a built 3.5 12V V6 in a 75/Milano.

Thanks,
MillsMotorsport
 

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39mm, same at both ends. Never heard of anyone flow testing them. Try emailing AHM motorsports in the UK.
 

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These inlet runners strangle the 164 24v 3.0 engine, restricting power to 211bhp, while the larger runners fitted to other 24v 3.0 engines and the 3.2 engines allow power of 230+bhp. If your engine is enlarged to 3.5 litres, thing your first port of call should be those larger runners. Think they are 43mm, off the top of my head - same diameter both ends.
Good luck with it. Sounds like a fun project.
 

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For the record, my GTV6 with a 164 motor and unmodified 2.5 GTV6 intake runners made 214 HP at the wheels - about 260 at the flywheel. The motor is NOT restricted by the runners.
 

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Larger intake runners on the 24v 164Q are how they get 230 hp. Adding them to the 164LS 24v is how they go from 210 to 230 hp so seems the larger size does make a difference on the 24v engine.
 

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Interesting fact: my 2L Nord motor makes 190 HP and it uses the smaller 1600 intake manifold - that is by design. Many people overlook the importance of intake gas velocity. Alfa certainly did on the 2L motors.
 

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Totally agree with Steve, Aflaparticle. Maybe your motor would make even more power with larger inlet runners? How do you know it is not being restricted? Which exact 164 motor do you have? No standard 164, even with the larger inlet runners, produced more than 230bhp.
 

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Interesting fact: my 2L Nord motor makes 190 HP and it uses the smaller 1600 intake manifold - that is by design. Many people overlook the importance of intake gas velocity. Alfa certainly did on the 2L motors.
Ed did you get your rear wheel HP reading on Al's Red Crown Racing Dyno?
 

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In the States we use HP. My motor made 214HP at the wheels on a chassis dyno. The transmission loss is about 18% and that corresponds to 260 HP.
How does your BHP differ ?
 

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Sorry, am not a techo person, just know HP figures read higher than BHP figures for same engine. Question still stands though, which 164 engine are you using to get such HP figures? Even a 24v 3.0 164 engine on 39mm inlet runners produces no more than 211BHP. And calculating a figure of 260HP from 214HP on a dyno is not an exact science - it is a guestimate. Depends on actual losses in transmission etc, as sure you know.
 

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Ed did you get your rear wheel HP reading on Al's Red Crown Racing Dyno?
I had it on Al's dyno and we blew the front Giubo. I ran it on a local Mustang dyno a few weeks later and posted the results. The reading on Al's just as it blew corresponded with the reading from the Mustang at the same rpm.

I also dyno'd my Spider on both the local Mustang and on Al's and again they were very close.
 

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The British outfit making the aftermarket chips showed dyno tests which demonstrated the difference in measured hp and torque with and without the larger Q intake runners. IIRC, one thing those curves showed that there was basically no loss of torque at lower rpms using the larger Q intakes on the LS, contrary to popular belief. Also demonstrated the gains from using their chips, of course. I have the Q runners on my LS, but not the chip.with the results. Stormer on the highway.
 

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Agree, Del. Power curves I've seen for the 164 24v engine with and without the 43mm inlet runners shows identical power/torque until revs are beyond, from memory, 5,500rpm +
 

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it is a guestimate. Depends on losses in transmission etc, as sure you know.
Here is my basis for 18%. Jim Steck built a strong 2L race motor for Hayes Flynn which made 215 HP on jim's highly respected engine dyno. 2 weeks later that motor installed in Haye's GTV race car made 175 HP on a Mustang dyno in Birmingham Alabama. That gives a transmission loss of 18.5%. The 115 and 116 gears and differential are very similar and the transmission loss in the two systems is similar.

Another data point is this: A few years ago a racer in the US bought a motor from Alfaholics with a dyno sheet indicating that it made over 210 HP. When they put it on the dyno that Jim Steck and Mike Besic use it made 190 HP.
You are deceiving yourself if you think that European dynos are more conservative than the ones that I and my friends use.

My 3L 164 motor that made 260 HP had 10:1 S pistons, a stock head and runners, a modified plenum and camshafts from Richard jemison, Megasquirt engine management and larger matched injectors from Al Mitchell, CSC headers from EB Spares in the UK and a custom straight through exhaust. The head, valves and runners were all stock. Again, I posted the dyno charts and the engine details on the ABB.
A guy that I know has a 3L, 12V that made 317 HP on a respected engine dyno. It wins races regularly.
 

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Sounds great, Ed. If you are doing that much work on the engines maybe it is worth considering using larger inlet runners, as even on standard engines we find noticeable improvements by doing so.
 

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The 215 HP Nord motor that I referenced has a 1600 intake manifold with SMALLER intake diameters. The intake ports of the head are sleeved. The Alfa details that you reference are old hat. Modern cams which are much better than anything Alfa offered work better with intakes that optimize gas velocity. Flow bench numbers are important but if not used properly may lead you to making the ports too big and lose velocity.
 

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Richard,
as a fellow Brit you may know this story. Towards the end of the initial development of one of the Coventry Climax race engines they sent the head to Westlake Engineering who were the porting and flow experts at that time, When the head came back the Climax guys saw that the intake ports had been enlarged and when they installed it on the motor and put it on the dyno they found that it made less power. Over-porting has been going on for at least 60 years. ;)
 

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Hi Ed, am indeed aware enlarging ports can be counter productive. Port/bore size is always only part of the story and too large a size can reduce the airflow speed resulting in loss of power. However, the only difference in the 164 3.0 24v engine between 211bhp standard and 230bhp Cloverleaf is the diameter of the inlet runners, going from 39mm to 43mm. The gains are all in the higher rpm range where airflow volume is more critical, while power curves are identical until this point. It is a win win.

Accept the 12v version may have different 'needs' but generating power requires both fuel and air so if your engine is generating similar or greater levels of power with 39mm inlet runners then surely, in terms of pure thermodynamics, given the gains for the 24v engines it is worth at least the experiment of trying the larger inlet runners? Alfa use them for a reason.
 
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