Chamber Grooves - what do you guys think?

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greg_nate
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Post by greg_nate » Fri Feb 24, 2006 4:11 pm

peerless wrote:Hey guys,

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:
http://www.revsearch.com/grooves/6200-4000.jpg
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?)
http://www.revsearch.com/grooves/beforegrooves.jpg
Runs after grooves (reader assumes this was after dyno pulls?)
http://www.revsearch.com/grooves/aftergrooves.jpg

Also backed up by this example:
http://members.cox.net/raunch/fabian%20r44.jpg

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
Image

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 :wink:
I couldn't find any dyno numbers for the Metric Mechanics head modifications.

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Post by putztastics » Fri Feb 24, 2006 5:17 pm

peerless wrote: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?)
http://www.revsearch.com/grooves/beforegrooves.jpg
Runs after grooves (reader assumes this was after dyno pulls?)
http://www.revsearch.com/grooves/aftergrooves.jpg
Both of those pictures were taken when the heads were off for grooving, before the dyno testing with the grooves. The first one is the untouched chambers right off the dyno. The second picture was after the grooving, not the grooves dyno tests. I did not take heads off the engine after the grooves testing was over.

There was a layer of soot in the chambers, the engine was not shut down under load before the heads were pulled. I think the chambers would have looked different if the engine had been shut off under load. The sooty carbon dust easily wiped off the valves. That soot could have been from the Klotz + 91 fuel.

The engine posted its best ever hp and torque peaks on 100LL during the tests of Klotz HiTRATE + 91, 100LL and VP C-12. It still was within 1-2 chp and ctq of its best pre-groove numbers in the 6200-4000 range.

I did not retest the 4000-2000 range with the three different fuels.
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liquigas
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Dyno runs?

Post by liquigas » Mon Mar 06, 2006 11:01 pm

Baseline shows proof positive benefits. Undisputed. Now make it roar.
Last edited by liquigas on Sat Mar 11, 2006 3:54 pm, edited 1 time in total.
-insert pithy comment here-

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Best Test?

Post by liquigas » Sat Mar 11, 2006 3:53 pm

Putzstats, what is the cost of a "best" groove configuration test?

timing, compression, gasses....
-insert pithy comment here-

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Post by putztastics » Sat Mar 11, 2006 4:42 pm

I don't know what you mean, the cost of two days worth dyno testing?
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Best Test

Post by liquigas » Sat Mar 11, 2006 5:17 pm

It seems to me that people are keen to test 'just' the Groove, ostensibly for some kind of scientific purpose.

I agree with Automotivebreath that one must also consider the advantages that a modification allows as well as the specific advantage of the modification itself.

If a regular engine can not be successfully set at a certain tuning of advantage, but this is allowed with the Groove, then it seems like the Groove has merit.

Is quantifying the exact benefit of the Groove channel (minus the added displacement which has been negated with head shaving) as important as seeing what a groove will do for most users?

I'm interested to know how much it costs to do a dyno pull on that engine with the Grooves and the most advantageous tune that they enable because this is what will happen when someone puts Grooved heads on their engine.

Who would Groove their heads and not take advantage of what they provide in terms of performance?

For instance, the benefits at high rpm might be negligible, but the "tuned" torque and HP might be greater at a lower rpm with the Groove, thus enhancing engine life (and whatever other benefits come from running a lower rpm).

Also, knowing what happens from idle rpm under load would show what is possible in terms of getting up to speed (relevant to the ¼ milers and regular daily drivers like myself) and apparently it would show great differences from the regular engine.

As for a two day test, it seems like this wouldn't require a repeat of the first example, just a comparison of the un-Grooved engine results with the new "tuned" Groove. As mentioned before emissions would be useful for a number of practical performance reasons.

It strikes me that for whatever reason, the advantages of the Groove have been downplayed to a large degree and no one has come forward to show what this mod actually means in terms of detailed performance potential.

I understand that you split the cost with Automotivebreath out of intellectual curiosity which I applaud heartily. Others have not come forward with their results for reasons that I cannot understand, so I am asking now, what would it cost to have you perform another test with the Grooved engine that shows what it is now capable of, as opposed to what the Groove 'alone' changes (which seems more like showing how a Grooved engine MOST resembles an unmodified configuration. Answer: +3lbs of torque)
-insert pithy comment here-

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Post by putztastics » Sat Mar 11, 2006 8:10 pm

The cost of that testing was 100% mine.

I did try different fuels, at different timing etc. 100LL made the best power, the engine was still within 1-2 hp of pre groove trim in the 6200-4000 RPM range.

Like I have said next time there should be some steady state tests for very accurate BSFC numbers before and after the grooving.

One more thing I could have tried was straight 91 pump gas. The engine had 165-170 cranking compression, 11 static and 9.19 dynamic (KB calculator) CR. So it might have run on 91 with the grooves. I'm not set up with any form of knock sensors, what I would do is wire them to headphones, so knock is not easy to hear. I do not think it was knocking but with the Klotz + 91 mix there was some run on after the engine was shut off, sometimes a sign the octane is a little low.

I still have my 360 test mule engine and could do grooves testing on that one. It has about .5 less CR so it would probably run on 91 with grooves.
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Best Test

Post by liquigas » Sat Mar 11, 2006 8:16 pm

(100% costs) My apologies, and 100%more sincere thanks for doing this test.

Are my other assumptions off as well?

What about the .070 space and higher compression used by automotivebreath? Timing changes?

My point being that setting the Groove to its maximum benefit would tell us about its potential more than [same engine, same tune but with Grooves]

Would what I'm suggesting take two days?
-insert pithy comment here-

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Re: Best Test

Post by automotive breath » Sat Mar 11, 2006 8:25 pm

liquigas wrote:...I understand that you split the cost with Automotivebreath out of intellectual curiosity which I applaud heartily...
As putztastics said, his testing was completed on his time with his money. Larry Meaux agreed to split cost of testing my SBC.

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Post by SWR » Tue Jun 13, 2006 6:32 pm

Old thread,but I just heard back from a "groovy user" today... I grooved a set of Arctic Cat snowmobile heads 4 months ago,and at the same time I took a couple 'thou off to true the heads. Not nearly enough to kick the CR up by any noticable amount,and told him to take a few degrees of WOT ignition out of it. Result?

The result was short lived... Quote: "It pulled like crazy when we tried it...never been anything even like it...then it promtly snapped the gearbox chain and totalled the 'box", end quote. :lol: :lol: ...guess I know what to do on my own ancient ET340P now. :wink:
-Bjørn

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Post by 1bolt » Tue May 20, 2008 10:37 am

(call me the dead thread resurrector) is it me or was this thread ended on a highly interesting tantalizing but still not conclusive note? 6 foot pounds in the low RPM range seems worthy of more investigation. Especially considering how easy the grooves are to create.

By definition, they don't do nothing, they obviously had a small impact with absolutely no tuning to optimise their effect...

Putz found interesting stuff then... a year goes by and no one is pursuing it?

Hell when I first heard about the grooves (AB on Hotrodders forum) I thought "great another stupid gimick. And more then a year later here I am reading a year old thread on it that prooves they have some mild beneficial effect... did the discussion migrate to a new thread?
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Post by automotive breath » Tue May 20, 2008 1:45 pm

The idea was covered in depth here, use the search feature. More recently
there has been several discussions on "Harley Tech Talk"

http://groups.msn.com/HarleyTechTalk/tc ... 6521222401

http://groups.msn.com/HarleyTechTalk/tc ... =0&CDir=-2

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Post by 1bolt » Thu Jan 08, 2009 7:11 pm

automotive breath wrote:The idea was covered in depth here, use the search feature. More recently there has been several discussions on "Harley Tech Talk"
I was using the search feature or I wouldn't have found this thread :) . Here i am resurecting it again (pet peave but why do some people hate when an old thread is brought back up?) Did you and Larry ever get together to prove this out with more testing an tuning for best power?
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Post by Piledriver » Mon Jan 19, 2009 4:07 am

I've been doing a little more research on my own, and have a slightly different theory about what is happening with the shaped grooves (not the Singh style grooves, the ones that provide texture, including the valves)

I suspect the added "texture" is actually doing the exact OPPOSITE of what the inventor holds, and is promoting a surface boundary layer, quite effectively insulating the head from combustion, also aiding combustion by possibly reducing surface wetting etc.

(This IIRC is an ancient 2 cycle head trick)

The patent is from ~1990 and is about expired anyway...

I am considering getting a little more radical and shot peening or trying a pin descaler...some piston domes and chambers for the effect and seeing what happens, thus searching here and stumbled on this old gem...

With the way the reynolds number changes, finding the "perfect" texture sizes migh be a bit tricky, for water the critical size to create a stangant layer would be a few thou... for "normal" air ..5-1mm or thereabouts IIRC. For what happens in a combustion chamber probably only actual testing in metal would really mean anything.

You would probably want to knock off any sharps with scotchbrite, and a thermal barrier coating could still be used.

All this is 180 out from what hot rodders and racers have probably been doing for 100 years... finding ~zero info on it so far.

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Post by automotive breath » Mon Jan 19, 2009 6:51 pm

but why do some people hate when an old thread is brought back up?

No problem bringing up an old thread. It's a subject that has been discussed
here for several years. I believe most of the top level people think it's BS
so they would likely rather see it die. Then again others swear by it.

I have never done any dyno testing, I called Larry and told him I wasn't
able to take him up on his offer.

I still cut the grooves when people ask for it, here's a set of SBF heads
I'm working on tonight.


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