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is there a white paper anywhere on the theory?

All the photo examples I see are done on 2 valve heads.. no workie on 4 valve/cylinder?
 

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Discussion Starter · #4 ·
Check Somenders site. After some research, about 6 hours of looking around, reading about other examples, it seems to be 100% solid.

There is alot of info out there, not yet have I found an example where someone who grooved the head properly has had problems, only gains in driveability.

I'm getting ready to groove my 531 head, first a single groove (from sqish area to chamber), then a 2nd groove at the spark plug when I get my metal HG. There will be no changes to the engine other than a Cometic or Rsport HG (same thickness).

I expect only good things.
 

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Discussion Starter · #6 ·
It has been tried on 4V heads. Can't find the article, but its a 16v Volvo head, 2 rooves (one in each squish area on each side of the head), but you can just have it pointing straight toward the plug. It only has to be about 2-4 deep. and about 1.5- 3 mm wide.
 

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probably the same effects...

i read this article in popular science, and at the time i didnt either read or understand that he was using the grooves to focus the blast from the squish zone into the sparkplug.

if you look at it like that, it becomes pretty easy to understand the WHY AND HOW that makes this modification work. ofcourse you are increasing the cylinderhead volume so you need to plane the head back to where it needs to be fore the right compression.

id love to try this but im too busy with other things to be swapping heads and building heads all day. so id love to hear more about people doing these modifications.
 

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i dunno, in a turbo app. i think it would be fine if the volume was slightly decreased, it'll only help ward off detonation.
 

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derracuda said:
i dunno, in a turbo app. i think it would be fine if the volume was slightly decreased, it'll only help ward off detonation.
I wonder how much volume on average the mod usually creates?
 

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a4kquattro said:
derracuda said:
i dunno, in a turbo app. i think it would be fine if the volume was slightly decreased, it'll only help ward off detonation.
I wonder how much volume on average the mod usually creates?
not much.... probably not enough to notice the decreased compression ;)
 

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u'd be suprized... a couple cc's make a difference. especially at higher compy ratios but still..

for example my jetski with 38cc domes runs 180 psi with an o-ring head. now if i throw a 10 thou thick gasket on there it drops to 150 psi.. quite the change.
 

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Im unbolting my spare V8 heads ....where the hell is that air file :)

This sounds like fun.....
 

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Discussion Starter · #15 ·
Ok, so it may drop compression, how do you explain the lack of pinging at such high AFRs. Read through the whole Tbricks thread. I was somewhat of a doubter, but when there are claims of increased driveability at lower rpms (pulling smoothly from 800-1200!). Granted, Volvo motors are known for the torque htey make, but still, I had trouble doing that in my 740 when it was stock with a TINY 13c.

Also, read about proper groove placement, don't get too close to the edge of the chamber, don't go too deep, and make sure its wide enough. TBricks should have plenty of good info (even if modifying a 240 sedan isn't your cup of tea, and all the guys seem insane, its a wealth of knowledge).
 

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Actually, this makes ALOT of sense. I was reading up a few weeks ago in the new Bosch Gasoline-Engine Management book concerning the theories and operation of direct injection. The new Audi FSIs can operate in a very lean burn mode that is possible by creating localized rich areas in the combustion chamber at the plug, even though the overall A/F ratio is very lean.

I haven't read any of Somender Singh's work, but it sure makes sense that directing a "blast" of mixture at the plug would improve combustion, expecially in an otherwise poorly designed combustion chamber. It is a different concept from direct injection obviously, but similar in that it manipulates the location and perhap local density of the mixture in the combustion chamber. I might try this on my old Triumph Spitfire. That old engine can use any help that it can get from a performance standpoint.
 

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I would like to see some real impirical testing on this stuff. As I jokingly said previousely. I would thing the best test would be to take a V8, rebuild the top end, do the valve seats etc and put it back togeather at factory specs. then install 2 knock detectors and some other montioring gear and run it for 6 weeks or so and get a lot of data.

Then Pull one head and groove it and get another 6 weeks of data, tehn pull the other and groove that and get some more data.

Then pull both heads and check everything for wear etc.

Would eb a fun experiment.

Timmmy
 
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