You are all talking theory here, (theory is good, I like it) but I like better talking in practice...
Have a read here what a modified head combined with valves and cams can do...
Just to clarify...this head is not modified by Thumper. It is made in Greece by a close friend of mine.
Interesting... see this OFF the build page noted in post one!
While looking for cams, I found
Thumper Performance, a source for reworking cylinder
heads. Personal opinion, this is a “must-have” upgrade! There are other sources for
similar work, but this guy has the references and experience. I could either send him my
cylinder head (gone for at least a month), or find a core for him to upgrade, then make
the switch. Originally, I wanted to change the head myself, but after looking at a repair
manual, I found that special tools / fixtures are needed. Iʼm equipped to work the old
“elephant engines”, but not these variable timing, ECU driven, high tech wonders. So,
after he put me in contact with a previous customer,
I obtained a TPR1, his upgraded
head with stock size valves, drove it to my local dealer, and paid a small fortune to have
them change heads. Very labor intensive! Found out the hard way that camshaft
bearing caps are part of each head and NOT interchangeable between heads.
While arranging for the Thumper head, I bought other upgrades and had them delivered
for me to install after the head installation.
So I only drove with the Thumper head for a
few miles before shutting down for more upgrades. The driving was not severe, just
casual, around town stuff, but the improvement was remarkable.
I Know nothing about a custom made head for this car...??( other than the TPR Ported Head)
And this stuff rocks.. 'cept it isnt in the runners on the head. Also the DI has the special PISTON Top to help with swirl and mixing... but there is NOTHING in the cylinder head that would cause engie fuel issues with the runners/throats/ and perofrmance valve job being ported and smoothed.
Patent EP0842352B1 - Intake system for a stratified charge engine - Google Patents
Interesting stuff though.. lol Just not on a r56 cylinder head.
Thumper