how about some combustion chamber pics

[Wreck]

I had a look at a hayabusa cylinder head 2.6 HP / CUI . Or 197 hp out of 1340cc , no rough texture in the combustion chamber . I was always under the impression the dimpling on a golf ball was to cut down drag by getting the air to pull further around the ball and create a smaller slipstream . Maybe dimpling on the short side of a port only to get the air to follow the port shape and not breakaway and leave a dead zone in the port ..
I can’t see the benefit of a rough area in the squish part of a chamber . Maybe down stream of the valves to again get the air to follow the path you want it to go .

[modok]

[Wreck]

[ac509]

[FreeBug]

I have to say, this is pretty interesting. When you look at the "stock" chamber, you see how much the designs have evolved. Those new chambers look good on paper, but I don't really have much experience with them, certainly didn't notice anything out of the ordinary, performance-wise.

I guess the "best" chambers show here are the JPM ones, and I think we can all pretty much surmise what needs to be done in (to) the chambers. I think there's some debate as to whether to park the gasses around the exhaust port for detonation reduction, or taking material mostly from around the intake to improve flow...I dunno. But the general idea is visible.

But there is a definate trend in the recent chamber shapes, and I don't think you can carve them out of a stock head without welding. By the looks, the new chambers should give some advantage, I'm just not sure if it's easy to isolate. Most of it is breathing, but some helps combustion quality and speed, too, I would think.

In my own stuff, I have found it interesting to set up a compass from the spark plug, and see what kind of areas are equi-distant from the electrode, and see where the farthest stock point is in the chamber.

[eashc]

With so many configurations to choose from are different shapes best for the size and use of the motor?

How would these work for a 1776?
Still need to open them up

[oprn]

Interesting discussion on finishes. I bought into the polished piston top and chamber theories years ago thinking that, as has been said, you want to retain the heat in the chamber for conversion to power. After taking the engines apart later and seeing all my hard work covered in carbon my feeling is that it is only beneficial for a few hours at best then the advantage is lost. No matter what finish you put on initially, in the end the finish is the same.

This all again likely stems from racing where engines are torn down regularly and not from real life long term engines.

[Wreck]

yup , 20,000km later . at least the carbon and oil (guides a little worn) was easy to clean off the smoothish surfaces

[mark tucker]

the better the quench/squish the less carbon buildup.and a leaner mixture can be safely run as more of it is automized better and more burns effectivly. higher CR can also be acheved and run with little to no detonation when done right with more squish.

[Floating VW]

I'm sure many of you have seen these already, but in case you haven't (and since I like to show them off anyway), here are my AA 043 heads that went on my 76mm x 83mm mini-stroker. I had them flycut down to 45cc before putting the mirror finish on the chambers. The rest of the chamber volume is made up in the dished (7cc) and polished piston crowns:

The golfball dimples went here:

X3 on the squish!
_________________
"It's time you started treating people as individuals, rather than mathematically predictable members of an aggregate set, regardless of how well that works."

[jpaull]

[jbbugs]

http://rexresearch.com/singh/singh.htm

This always starts a flame war.
_________________
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69 OG paint Transporter
73' Super Beetle Champcar Endurance Roadracer
Patina my ass, that's a Rust Bucket!

[jpaull]

What does everyone think is the most common, hotrodded, and the most horsepower building combustion chamber in the world now?

The LS Chevy. Now, what is the most advanced version of that cylinder head and that chamber?
The LS9/LSA. Came stock with boost, extra webbing, titanium intakes from the factory, can be adapted to any LS engine and its not expensive.

This is how some of the best head companies like Lingenfelter/Westcoast Racing do their Hot Rod port upgrades to extract every last horsepower available:

Yes, this is 2020, Wait, Polished chambers? I thought that was debunked back from the olden days and it doesnt matter cause it just gets covered in carbon?

Do not do what the LS guys are doing, you dont want to listen to these guys that are putting these on 2500hp cars, they know nothing.

Please dont do what the lingenfelter people do, those people are fools:

Dont do what this vw idiot does, he is the blind chasing the blind...

By all means, do not do these weird things that dont make sense. Nobody is trying to convince the ones that dont want to, or dont agree. Keep on the way you are going.

[Brian_e]

Just goes to show people are more likely to buy shiny things I guess.

I also think it is a somewhat unfair comparison since the V8 guys have water cooled heads and head temps are of little concern to them, unlike head temps being near the top of concerns for aircooled guys.

I really have no idea which surface finish will work/cool better in an AIRCOOLED head. I don't think anyone really knows, or has done extensive testing to figure it out. I am really not too worried about it, but I do know I hate smoothing ports with just a cartridge roll. I can't imagine having to do a mirror finish.

I will just keep my fast super rough ports and my carbon covered chambers, and continue to drive lots of cool running miles on them with a smile and not a worry in the world about them.

So, just for discussion...thermal barrier coatings have been well received, and used in most every form of racing for over 30 years. The theory is to keep the heat in the chamber where the heat can be used to make more power rather than absorbed into the head as wasted energy. So would a thermal barrier coating be similar to a polished chamber, or a rough and carbon coated chamber? One might reflect the heat back into the chamber, and the other one might insulate the head from the heat....

PS...I do like LS engines. Built lots of buggies with them in a previous life. Pretty sure none of ours had polished chambers, and if I were to do it nowadays, I would probably rough them up really good.....

Brian
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www.type-emotorsports.com

[Dan Ruddock]

Yep, the 4 year old kid will always take three shinny pennies over a corroded quarter.

[sled]

just let it go jpaull.

its like you can't stand to have people with differing opinions than you and keep beating it into us until we say, "you're right! theres lots of shiny chambers on google images so they must be better!"



I personally would like to try coated chambers/exhaust ports and piston tops on my turbo 2234 build
_________________
drive your split.

[modok]

I don't see why the chamber texture ended up being the topic. It makes very little difference to how the engine runs.

If you have a hammer everything looks like a nail.
If you have a buffer...

Larry Widmer said "the chamber does NOT like looking at itself in a mirror"
Which, is true.
The piston on the other hand, I think it does not mind.

[jpaull]

[Chickensoup]

[sled]