ALFAGTV6.COM

[maxiboy]

hiya Jim

have you ever done any dyno time or flow bench testing with a polyquad type head design on this engine

[Jim K]

No I haven't. Although Vizard's articles are very interesting and well-documented, for the time I want to keep costs down -ie, not replace half the seats and valves with bigger ones.
Jim K.

[Maurizio]

No I haven't. Although Vizard's articles are very interesting and well-documented, for the time I want to keep costs down -ie, not replace half the seats and valves with bigger ones.
Jim K.

Jim,

Not hindered by any knowledge.

Maybe a simple low budget idea about this one, but will already too late, as work on the head is already done.
So you probably are making the flow better by minimizing the lay-on surfaces of the valves, changing to a 3 angle seat cut (if the head not already has it) and cleaning up the ports.
What about only doing this on only one of the two seats and then in a x-pattern per cylinder.

So make one port better and leave the other one standard.

[Jim K]

Nah, I'd rather do these heads the normal way and save the other spare engine for bigger things. However, I must hurry and finish before this useless country goes bankrupt!
Jim K.

[75evo]

Bigger things eh? 3.7 ?

[Jim K]

I have always preferred to stay within factory displacement. If this doesn't change in the near future (senility and such ) I may explore how far the na 3.2 can go. Its too early to think about that though, there's still lots to do to finish the current 3.2.
Jim K.

[75evo]

Senility......

Hey JK, so when are you going to ship me the 24V ITB you promised to sell me for $100??

[Jim K]

Ehhh, something wrong with the zeros on your keypad there? One more zero and you got it!
Jim K.

[75evo]

haha, that was just a quick quiz to keep you in check. Like your teeth, your brains are still very sharp!

Do you know how Honda can make their factory 2L go to 8K RPM on a production Type R. Can we do the same with the 3.2 crank with "improved" oiling. BTW is it only oiling? I"m guessing it has to do with how stable your block is at 8000 rpm, right?

Have you thought about a steel girdle? Maybe not practical, but is such a thing needed for the V6 to make it reliably go to 8K? Alexis Walter's GTV6 goes to 7.5-8K rpm, at least that was what he told me. For a 12V I see no point, but for a 24V, with relatively light valve train engine speed is your friend, innit?

I may not do it, but just something Ive always thought about.

[Jim K]

I went to our 3-day track meet last month and the 24v 3liter was perfectly happy sitting at 7-7800rpm 3rd gear for ~8sec per lap on the back wide curve and this engine has std rods/pistons! In my opinion, no steel girdle is needed. If I can do this with the Williams profiles, I can sure do more of it with my 10.3 ones. However, I would feel more reliable with mechanical followers (lighter than hydraulics) stronger valve springs and of course forged pistons/rods. As a matter of fact, I would believe exceeding 8k is no big deal. To do that productively, your intake/exhaust system must be designed accordingly = race engine, which wouldn't be happy on the street meaning I for one will not do it, as I like to drive what I build -not just on track. Even the 3.2 78mm stroke is a joke for an engine with the right parts I mentioned. Following is the analysis from one of the simulator runs for my hypothetical 3.2 engine. Read what it says about piston speed, the most critical rpm-related parameter:
Analysis Report for Full Race Engine with Desired HP Peak at 7200 RPM

Peak Tq =257. @ 6000 RPM 1.32 Ft Lbs per CuIn
Peak HP =337. @ 7250 RPM 1.74 HP per CuIn

Maximum Tq/CuIn is 1.325 Ft Lbs/CuIn.
This is somewhat high, indicating good performance, but will
produce high cylinder pressures and temperatures. Check the outputs
'Mx Cyl Pres, PSI' and 'Mx Cyl Tmp, deg F' for actual numbers and to
more precisely watch trends.

High cylinder pressures require precautions to protect against
detonation, blown head gaskets, damaged engine components like
pistons, rings, exhaust rocker arms, bearings, etc. Check the
outputs Mx Cyl Pres and Mx Cyl Tmp.


Maximum Exhaust System Backpressure 'Exh Pres' is 1 PSI.
This is somewhat high for a race engine. Racing exhaust systems
should not produce more than .5-1 PSI Exh Pres or they may severely
limit Tq & HP. To simulate open headers, set Exh System to an Open
Headers or set the CFM Rating to a higher value in the Exhaust
Specs menu.

Typical ranges of Exhaust System Backpressure are listed on page
32 in the User's Manual. You can lower the Back pressure by
increasing CFM Rating in the Exhaust Specs menu or specifying
Open Headers. Lowering the CFM Rating will simulate a quieter,
more restrictive exhaust system. Most dyno tests are done with
Open Headers, which are simulated by selecting Open Headers.


Maximum Fuel Flow 'Fuel Flow' is 171 lbs/hr GAS.
This is equal to 29.2 gallons per hour of fuel flow.
For an injected engine with one injector per cylinder, you will require
at least 29 lbs/hr injectors.

Fuel Flow will only change if air flow changes or you select a
different type of fuel. The Engine Analyzer Pro assumes 12.5:1
A/F for gasoline and 5:1 for alcohol (methanol) for all
conditions. You can not richen or lean out the fuel mixture.


The Average Piston Speed 'PSN SP' is 3685 ft/min
at your DESIRED HP PEAK RPM of 7200 RPM.
This is Very high, requiring strong, light reciprocating parts.

The Maximum Average Piston Speed 'PSN SP' is 3967 ft/min
at the Performance Calculations Maximum RPM of 7750 RPM.
This is EXTREMELY high (if you want to run this entire speed range),
requiring light, high strength reciprocating components.

A race engine should limit PSN SP to a range of 3750-5000 ft/min. (Race
engines on the 'leading edge' of technology are running up to 6000
ft/min.) To run over 2750 ft/min requires 'better than production'
parts. To run at 3750 ft/min or higher, you will need 'state of the
art' reciprocating components (connecting rods & bolts, pistons, etc.)
like those present in Drag Racing's Pro Stock class or Formula 1.
These components must be both extremely light and strong.

PSN SP (average piston speed in ft/min) and PSN GS (peak piston Gs)
are indicators of how severely you are stressing the engine's
reciprocating components. To lower PSN SP and PSN GS, you must
shorten the piston STROKE or design the engine for a lower RPM
range. See pages 53, 54 and 160 in the manual.

Maintaining low PSN SP and PSN GS are critical for 'keeping the engine
together'. OVER-REVVING PARTS BEYOND THEIR INTENDED LIMIT IS UNSAFE
FOR THE ENGINE, YOURSELF AND BYSTANDERS.


Based on 'Simple Rules of Thumb', good Inertia tuning should occur at 6600 RPM,
which is close to your Desired HP Peak RPM of 7200 RPM.
Since this RPM is about where the HP peak should occur, peak HP
should be good. If you specify longer and/or smaller diameter intake
runners, you may gain Peak Torque and lose some Peak HP.


Maximum Knock Index is 2.9 which indicates detonation
(spark knock, ping, etc.) is Very likely to occur.
You should try a higher Octane fuel, lower Compression Ratio, to
reduce the possibility of detonation. You can also try specifying
a spark curve with less advance which will likely hurt performance, but
allow this engine to safely operate with a Knock Index less than 2.

You can reduce the likelihood of detonation, by increasing FUEL
OCTANE or DEW POINT (humidity), or reducing INTAKE AIR TEMP or
COOLANT TEMP in the CALCULATE PERFORMANCE CONDITIONS menu, or
reducing COMPRESSION RATIO in the BASE ENGINE menu. Also, anything
which reduces performance, or shifts the performance curve to a
higher RPM range will also reduce the likelihood of detonation. You
can also specify a spark curve with less spark retard than what the
engine is currently running. See Spark Advnc in the results.

Retarding Spark Advnc is not necessarily a 'bad thing'. The best
performance for a particular RPM range and FUEL OCTANE may come with
retarded spark. Just be sure to retard spark in the actual engine
to avoid detonation which will cause engine damage.

Also, retarding the spark curve usually increases exhaust temperatures,
which can damage exhaust valves, turbo turbines, etc.


Estimated Idle Vacuum 'Idle Vacuum' is 15.3 ''Hg.
This is Very high and would provide for a relatively smooth
idle. However, for a race engine, it may be indicating the cam
does not have sufficient overlap which may limit full throttle
torque and HP.

To reduce idle vacuum for possibly better full power performance,
increase cam overlap by specifying a higher Duration @ .050'' for
both the Intake or Exhaust in the Cam/Valve Train menu.

[Mats]

Feet/minute?
Are you kidding?

[Jim K]

Well, it could be a lot worse, like ...yards/second for example!
Since 1974, most of what I've read was in ft/min so it doesn't sound strange! You can select inches/mm in the simulator operation from the 'preferences' block but the report does not go metric.
Jim K.

[Mats]

Backyards per hour? Sounds like a lawnmower unit...

As far as in/mm, it's ~0,039370078.

[Maurizio]

Backyards per hour? Sounds like a lawnmower unit...

As far as in/mm, it's ~0,039370078.

Mats,

We don't want the lawn mower engine to explode at first startup.
So we are talking scientific numbers here so: ~ 0.03937007874015748031

[Jim K]

I suppose your next post will be about the 'correct' 'π' and not just 3.14?
Jim K.