.

thx jon , my opinion is the pre HE inlet port narrows down just before air enters the valve bowl that increases velocity and the valve is slightly offcenter, and that induces some swirl to produce some tubulence in the cylinder for better mixing.

thought to be the main draw back of pre HE chambers and ports!

your heads are in a different type of air flow, and only time will tell!

that is why the G44 and TWR heads are completely different ports , both inlet/exhaust, big ones , all on the top end HP area!

Ron

 

The bowl in the HE head is offset as well, so I don't think there is that much difference between the HE and pre-HE apart from the intake valve being recessed into the head, this would have reduced the size of the bowl.

Where the port narrows at the guide just before the bowl causes a venturi effect as the air expands into the bowl it slows making it easier to turn. As I do not have an engine dyno I will err on the conservative side with the ports. I do know going too big will kill power eveyrwhere.

Below is a port mold from an Aussie V8 supercar which makes 600+hp at 7500rpm from 5.0L. These are one of the most hightech engines around even though they are pushrod. The venturi is clearly visible before the bowl.

 

jon i agree , believe it or not, i was explained that very principle about port and bowl area, back in 1955,YIKES i'm gettin old!

a guy had just come back from England, and was a motorhead type,(motorcycles), i had a
1952 Triumph 650cc THUNDERBIRD, and he went into detail about that port area!

he called it the throat to seat waist shape, like a womans waist! ??

oversized valves did not help that principle shape.

it was different than most US guys were doing,(just hogging things out big).

have fun, any date for engine fire up? but dont rush , todays ideas are totally different!

engine tuning has come lightyears in last 60 odd yrs!

 

to add, NASCAR engines are getting 800hp from 5.8L at 9000revs, pushrod 2valve!

amazing tech on either engine, both show how much things have advanced!

ron

 

The V8 supercar engines are rev limited at 7500rpm and all cars have monitoring to ensure they do not exceed this limit. These cars run at Bathurst 1000km of almost qualifying laps and very few engines expire. I guess to keep costs down, so engines are cheap only about $150k each. BTW these engines are so tightly toleranced that they have to pre-warm them prior to starting.

Unfortunately engine is on hold until my broken wrist heals. I can not hold a fork ATM. Had surgery last week to screw it back together.

 

If space allows, you can insert resonating tubes and get the pseudo supercharging


XKR 2004

 

HMM,, now thats a nice smooth air flow,,LOL<LOL NO NO NO.

related to an Octopus?

 

some one can only do that IF
and only IF
they can do the MATH!

having the Baseline VE numbers is a start and all the dimensions all the way to the back of the intake valve(s)...

then you can start your resonance calculations... for each rpm you wish to improve the VE at

what a system!
P.S. what did that come off of? intake valve size is about 0.85 the outside diameter of those pipes? and each one is a harmonic length related to some RPM at what ever VE. * manifold pressure, ok FUN

 

intake air flow is not a FLOW
it is a series of pulses...
at resonance it is greatly improved
think of it like tuning a "PIPE ORGAN"

 

My 1998 XJ8 has ONE resonanz chamber but it is actually supposed to only be there for noise cancelation.

I removed it prior to fitting the gas system (I wanted to use the space under the rear engine cover to hide the ECUs). Not a change at all. IF it is for a "supercharging" effect, then it is soooo small, so minor, that it is impossible to feel... Though it doesn't help that my exhaust offers so little resistance, that according to the dyno I was on (2015), the car has not 237 hp (240 ps) but all of a sudden, calculated back through tranny losses etc., something like 268.3 PS (or so). I've got to see if I can find my results again Torque figure though dropped by 3-5 nm (instead of 320 nm it has like 315 nm) but I was told that was a possible drag of the tranny or the tires (I have the largest size possible for 16" rims).

 

it only pulses in the runners, not in a proper plenum chamber, and the best of engines use a large plenum(albeit not a small one like jag V12), it nullifies pulses somewhat, but measures at the TB its quite a steady flow!

also for my type of car ,i like the sound of the throttle plate opening, a HISS transending into a ROAR!

ron

 

He wrote in the picture subtitle, that it is from an XKR from 2004, so an X150... V8 of course

 

lots of designs use plastic manifolds and put the throttle body at end
I remember my dads old ford that when he would rev it up you would hear a pop and it would die...
why because the plastic part was not attached firmly enough the suction would foreshorten the length and pull it off ... better hose clamp help out..

 

Yes plastic is a good material for a manifold as it sinks less heat.

My plan is to make new manifolds from fiberglass - molded from the OEM but with bigger plenums and straight 33mm ID runners.

Those tubes hanging off that intake are purely for noise suppression, Resonant chambers tuned to a specific frequency (Helmholtz Chambers). Holden uses a similar setup on the LS2 V8's and the OEM modified LS2 in the HSV deletes these in favor of straight pipes with no resonant chambers.