PolyQuad head design, +100HP potential

[MrDangerUS]

Four-valve heads are certainly "cool", but comparing to modified 2-valve config, they exhibit a certain flaw - low speed torque is never impressive.

The key to making low speed torque is two-fold:
a) how much charge is trapped at valve closure and
b) how effectively the charge is burned."
Replacing 4V head charge "tumble" with the "swirl" motion presents itself as a key element of the successful (re)design.

To read more about PolyQuad head design, read this article:
Polyquad Article - MotorTech Magazine

If anyone wants a PQ head modified (be it for any multi-valve head), then Ultra Pro Machining in the USA http://www.ultrapromachining.net/About.html (704-392-9955), who does so many cup car heads, or Austec Racing in the UK http://www.austec.co.uk/Cylinder-head-Modifications.asp

(01293 531080), are up to speed on this.

[Fueltheburn]

The problem with Austec Racing is they don't take Non- TVRs very seriously... or at least they never used to. 

Reputations are a hard thing to shake.  I used to live 2 minutes away from them

[Bibs]

I was there a couple of weeks back. Seems very Pork orientated now.

[DanR]

When I opened the link I saw the name David Vizard so got my full attention. His work over the past 40 years or so is the stuff of legends.

 

Bit long to read at the moment but will do so when I have some more time.

[Simon350S]

Spent the day at Austec along with Bibs, very much both Porsche and TVR but keen on other modified cars too.

[MrDangerUS]

Austec is not that important/relevant in the overall scheme of things.

 

Read the article. PolyQuad concept is amazing!

[MrDangerUS]

When I opened the link I saw the name David Vizard so got my full attention. His work over the past 40 years or so is the stuff of legends.

 

Bit long to read at the moment but will do so when I have some more time.

Yes, David is a world renowned expert on engine design and development for automotive and marine applications. As the critically acclaimed author of over four thousand technical articles and 32 technical books, he has earned a global following of his ground-breaking work, with specialist areas in Mini, Ford and Chevrolet. He has a Patent for PolyQuad head design.

[MrDangerUS]

Here is an updated article:   http://www.motortecmagazine.net/the-future-of-4-valve-engines/

Nex time your head is out, if you decide to "PolyQuad" it, it can be done by David Martin of Austec Racing  in UK.

[drdoom]

Mr. Vizard's credentials are impeccable and I've read through much discussion in forums in regard to his Polyquad theory. The concept is persuasively described in the articles, however not a single example of the outcome realized has yet been presented by anyone, including well established tuners. It has also been noted by some of the professionals who contribute that some of the desired swirl has been accomplished by nothing more exotic than offset grinding the 2 intake cam lobes per cylinder several degrees apart. That said, I do not presume to know enough to dare challenge the like of DV in these matters, just wish someone would get a 907/912 done in Polyquad fashion and share documented results! 

[Vulcan Grey]

Surprised you haven't mentioned Turbulent Jet Ignition

https://www.enginelabs.com/news/f1-tech-what-is-turbulent-jet-ignition/

[CHANGES]

On 26/10/2019 at 17:40, drdoom said:

Mr. Vizard's credentials are impeccable and I've read through much discussion in forums in regard to his Polyquad theory. The concept is persuasively described in the articles, however not a single example of the outcome realized has yet been presented by anyone, including well established tuners. It has also been noted by some of the professionals who contribute that some of the desired swirl has been accomplished by nothing more exotic than offset grinding the 2 intake cam lobes per cylinder several degrees apart. That said, I do not presume to know enough to dare challenge the like of DV in these matters, just wish someone would get a 907/912 done in Polyquad fashion and share documented results! 

I started reading David Vizard's info way back when I was racing a 1962 Mini cooper 's' in the late 70's  His information I followed through the many years I spent modifying engine's..  Its the little points added together I feel make the biggest gains.  These as a package do work , individually not so well..  So many people when tuning engines concentrate on the bolt on or easy to do,  accuracy and detail become secondary .  That is where they fall down..  There is little point reading Vizard and other tuning data if you do not implement all what has been stated and proven..  More important the modifications specified in these articles  are on a particular engine types/designs.   As a result any tuning info should be used as a guide when exploring a different engines/designs.   As owners looking to modify or improve the 900 series , the basic DV tuning and flow information is very valid.  However its application will depend on your projected outcome and component compatibility.   This forum has some threads that outline the simple to the extreme , specifically on the 900 series,  these are worth consideration  in conjunction with DV and other tuning data when undertaking modifications.. Unfortunately very few of these  have dyno data to back up claims , but by cross referencing with those that do you will be able to form a basis to work from..  

As far as 'Polyquad' is concerned , it would seem to have great merit in design initiative and application,  but not sure where such radical changes and  expense could be justified on the 900 series for a road use Esprit.   A bit like the Turbulent jet ignition @Vulcan Grey pointed out..    Great idea's and design's but maybe a ''Bridge To Far'', especially  when you consider the power / torque  we have so far extracted without them..   

Saying all that i do understand where @MrDangerUS is coming from with this .  Another area of development to explore ..   However I do feel we have already exceeded the peripherals of the 900 series with the power already extracted , so my immediate attention is on the drive train to handle what we have , along with a few energy saving / parasitic loss reduction idea's yet to be implemented..  After that who know what will present its self as needing ' Changes' 

             

[drdoom]

Great stuff as usual Dave. I would add that DV's emphasis is on shoring up the lower range efficiency of a 4 valver so should therefore imply minimal concerns for either peripherals or core components it would seem.

Cheers