New to the forum, but not new to engines or cars. Built a few and am working on another. I have been following this discussion avidly...well at least the last 2 hours reading and checking links.
I read an old popular science mag, and it had the article on Somander-Singh. I was skepticle but very interested. Tonight I found this link, and what a huge suprise to see so much interest in this subject.
My main interest in this concept is building torque. I certainly don't expect this grooving technique to give me tons more torque, but every little bit helps. I am building a BMW 2.7L, concentrating on torque.
If I could I would like to make some comments and rehash a few old pics, and throw in a couple new ones
First regarding the dyno test's that where done. While it seemed that this "grooving" technique didn't produce any significant results. I did notice a few things. One is the obvious drop in EGT's, This was without a timing or fueling change. That in itself says something. The other peice I noticed that nobody seemed to mention was the "smoothing" effect on the torque curve.
Take a second look:
The 4000-2000 wide open throttle sweep tests proved to be more interesting. In the best case scenario there was a 6.5 ft. lb. average torque gain in the 2200-3500 RPM band.
Comparing the best before groove 4000-2000 wide open throttle test to the worst after groove test still shows a 2.68 ft. lb. average torque gain in the 2200-3500 RPM band.
Note to the results are the "Worst After Grove" results compared to the "Best Before Groove" results. And it is still gaining torque. So I am curious, what was the "Best" before and "Best" after groove comparisions/results?? Inquiring minds want to know??
Also following 2 pictures say a thousand words concerning complete fuel burn, remember there was no change in fueling or timing!
(See assumptions made by me)
Runs before grooves (reader assumes head was cleaned before dyno test?)
Runs after grooves (reader assumes this was after dyno pulls?)
Also backed up by this example:
So it is obvious that the grooving technique is a seeminly positive improvement in combustion effeciency. I think that the power gains come from taking advantage of tuning with this improved volumetric efficiency.
In my opinion I think that another dyno testing session should be held and this time add more fuel and play with the timing, I bet you get some torque gains to talk about. So what ever you do don't let this idea be a fleating passing. I think it holds potential for a lot of enthusiast/racers/DIY's.
Promised some new pics.
Someone earlier mentioned metric mechanic, well here is a pic of there grooving technique, and a aritcle link for further info. They have some dyno proven gains. http://www.metricmechanic.com/pg28.htm
The picture above shown is a BMW 2.5L head and uses a crowned piston. The cylinder head my engine uses is a semi-closed chamber. I unfortunatly dont have a picture of my chamber, but has same valve arrangement and 2mm smaller valve size. Here is a picture of my new 9.5CR pistons, raised the dish to achieve higher CR. Compared to original cast piston:
http://img.photobucket.com/albums/v176/ ... iston3.jpg
http://img.photobucket.com/albums/v176/ ... iston2.jpg
Point being I want to build for torque, and what ever mods I can do safely and effeciently are on my top priority for the new engine. I will find a picture of the combustion chamber so maybe you could give me advice on how I should groove it.
Sorry for the long post