Grooving combustion chamber?

[SilverXJ]

The head polish and port thread with numbers reminded me something I saw a while ago. I've see a few people mention the benefits of combustion chamber grooving. The way I see it is that the forces air and fuel mixture into the channel and creates sort of a jet into the combustion chamber, increasing swirl and making the quench area more effective. Any merit to this?

I think the big name in this is Somender Singh.. I would only gloss over his site as it reads like an infomercial.


http://somender-singh.com/content/view/68/49/

[Flash]

I thing its a grate idea...........and i can see how it would help............but how big of a groove, what angle, point to the exh valve to cool? Or Point to the intake to mix better, one groove.....2 .......10 Will the groove encourage a crack.......and last but not least, theses groove will need to be polished to prevent hot spot (Pinging potential)

Sorry, i know i didn't answer you question............Just added a few more


I thing if i was to install a groove it would look like the one in the pic............pointing to the spark plug.


Flash.

[1bolt]

http://www.gofastnews.com/board/economy ... s-yet.html

My opinion is that they offer some slight unpredictable effect based on at least one believable dyno test showing a very small increase in torque.

Other than that there's a WHOLE LOT of anecdotal "evidence" from people who can not tell you why it it works, or even how many grooves to use, what shape, or direction to make them in...

Problem is with no known scientific methodology for them; If you happen to accidentally place them them in a non-compilmentary manner you may see some sort of EFFECT, but there's no way to say what that effect will be. There's nothing but speculation on the how or why.

In that thread I was hoping to goad David Vizard into testing the grooves, because he is very experienced with not only AB testing but also fairly and accurately tuning for best power while dyno testing two different setups... In other words he wouldn't just test before and after the grooves, he would also test with best timing advance and mixture settings for each. Testing until he couldn't squeeze another HP or pound out of either one.

Until someone shows something more than two or three foot pounds, and explains how and why they got the gains, the grooves are not worth messing with... Unless you believe that you can accidentally arrive at the correct size shape and orientation for your grooves without there being any possibility of accidentally making your engine run worse...

Basically would you deck your block with a belt sander? Do a valve job with with a drill press? Of course not, because you know you need more precision than that.

How then do you know that the groove you put in your quench pad isn't HURTING swirl? Interfering with the flame propogation? Slowing down combustion?

How deep, long, and wide, and where exactly do you point it.... Until someone can answer those questions it's all just psuedo scientific snake oil. IMO

[Comanche91]

Errrrrrrr, I'll pass for now.

[SilverXJ]

On his site he does tend to contradict himself a lot.. also.. in the FAQ he recommends a quench of .070 over .040.

It just really bugs me that this guy's site reads like its an infomercial. Like Billy Mays needs to read it.

[yuppiexj]

On his site he does tend to contradict himself a lot.. also.. in the FAQ he recommends a quench of .070 over .040.

It just really bugs me that this guy's site reads like its an infomercial. Like Billy Mays needs to read it.

I'd prefer Vince from the Sham-wow commercials, that's a spokesman that comes across pretty slimy

[SilverXJ]

I'd prefer Vince from the Sham-wow commercials, that's a spokesman that comes across pretty slimy

LOL.. priceless


http://somender-singh.com/content/view/10/25/ that just doesn't sound right....

[Comanche91]

When I see either one of those two fools hawking something I tune 'em out immediately. But the bastids must get results or they wouldn't show up so much.........

[Alex22]

Basically would you deck your block with a belt sander? Do a valve job with with a drill press? Of course not, because you know you need more precision than that.

You would be amazed at what will work. I have seen many sins committed on engines by "rebuilders," and then had to fix them. Chainsaw finishes on decks of blocks is fairly common.

To the topic...
It is an interesting idea, use the quench area of the piston to force the air fuel mixture toward the spark plug. Odd variation of a system that actually works. A few things I can see wrong with that particular design. There is just a trough cut into the deck of the cylinder head but nothing leading towards the trough to actually make the A/F mix go towards the spark plug like a water pistol. It looks like there would just be a space in the quench are of that chamber that is just kinda dead and turn into a slow burn.

I haven't actually seen this before, but some of the guys I work with have seen cylinder heads that have an angle to the chamber to push the A/F mix towards the spark plug and they use a piston with a ramp built in to match the angle of the combustion chamber.

Just thought of this as I was typing. Could the trough act to separate the quench area into two pockets and creating swirl in the chamber?

~Alex

[SilverXJ]

Just thought of this as I was typing. Could the trough act to separate the quench area into two pockets and creating swirl in the chamber?

Possible, but I don't see how one could verify that.

I also read the allpar site such as this: http://www.allpar.com/fix/holler/valve-prepping.html where they put groove sin the intake valve... then here http://www.allpar.com/fix/holler/head-porting2.html where they put some more groves in the intake tract.

[1bolt]

Powre Linz and Powre Ringz... I bet I'm not the only person who finds the believability of a mod to be inversely proportional to the amount of intentional misspelling... Using Z's in place of S' alone is worth -9 points on my personal 10 point scale of skepticism, forget about "PowRE".

That said they do have some immediate scientific merit, boundary layer flow will be effected by the sharp ridges... However how it will be effected and whether it will be a benefit to the type of application you have, or a negative, is very open to question... There are definitely some OEM designs out there that incorporate flow and mixture controlling aerodynamic shapes like lines and nodules. Problem is the OEM's have the kind of equipment and Engineers that can actually develop something like this for a specific predictable effect.

Even the Jeep head has a series of light lines across the direction of flow in the ports that I've always assumed where intentional. And its common to see valves with a tiny "trip line" built in, intended to trip liquid fuel up into the higher velocity flow above the boundary layer. Racers using higher RPM ranges tend to remove this during valve jobs for max flow because at higher RPM's fuel doesn't fall out of suspension nearly as easy... and the lower RPM benefits are worthless to a car that launches at 3000 RPM or spends all day circling around at 6500.

[SilverXJ]

Powre Linz and Powre Ringz... I bet I'm not the only person who finds the believability of a mod to be inversely proportional to the amount of intentional misspelling... Using Z's in place of S' alone is worth -9 points on my personal 10 point scale of skepticism, forget about "PowRE".

That just shows how out of touch you are with current performance trends. What you need to realize that the more the product name butchers the english language the more power it provides.... also stickers add hp, as I am sure you know. However, if you combine the butchering with the stick you get a double power boost.

[Mgardiner1]

also stickers add hp, as I am sure you know.

General rule is 1 HP per square inch of sticker



LOL

[1bolt]

LOL, damn I have a whole bunch of stickers that I've been meaning to put on the XJ I should be able to break into the 14's or even high 13's... I've got a big Dodge R/T hood graphic I was going to incorporate onto the "Hot rod XJ's" design before plans changed it ought to be good for 10hp all by itself

Seriously I do have that decal... only problem is Life changes things and the formerly Hot Rod XJ that was going to get a Turbo and be a Hybrid lifted street machine, is now going to get an Eaton M90 bigger tires, off road bumpers and rocker replacements and go back to being more of an off road beast which was how the engine was cammed in the first place.

I'll save the Turbo and the R/T graphic for a 2 wd Comanche street strip project I have in mind for the future.