combustion chamber softening

[larrym]

Hi guys been laying in the weeds not doing much with the car did some chassis and suspension work she rolls pretty straight and true now, we only had 1 test and tune event last year and 1 race this year with Covid restrictions.

I have a question about chamber softening to help reduce detonation, has anyone ever played with this or do you know of any that has?

https://www.facebook.com/watch/?v=218838686709646
 

[Steve Wood]

I think he created the term softening but I have not been reading much lately.  If I understand correctly, he is trying to to improve the quench effect to improve mixture consistency and reduce the possibility of detonation.  This all goes back to closed chamber vs open heads and domed Pistons vs flattop/dished Pistons and the effects of performance vs emissions   Here's a link that might help.  

https://www.enginelabs.com/engine-tech/quench-unlocking-performance-squished-between-the-piston-and-head/

[larrym]

Thanks for the link Steve, I think the idea is to reduce quench area on motors with power adders like the hemi heads, what I have read is quench areas will work well if its tight the quote on the video was "knocking the carbon off" with the soften combustion chamber you have a larger tuning window without having to get the piston to head clearance very tight. I'm sure there are draw backs just doing some research to see if it been done for our application do our dished pistons have the same affect I wonder.






 

[Steve Wood]

If we ignore the difficulty of running zero, or near zero quench, then the question to me is what kind of compression ratio are we going to end up when using a piston with a flat top piston.  Maybe they are using a semi-dished piston?  Dished on the plug side of the piston....  I think more info is required.  I also wonder how much intake valve flow is negated by the zero?  Need to go back and look at the piston, I guess

[Steve Wood]

in the end, we want an equal distribution of F/A mixture and a smooth growth of the flame front from the ignition source along with no "hot spots".

This is probably easier on a TF type of engine with a short and limited operational range than it is on engine similar to what we run.

[Forzfed]

Have you ever heard of anyone chroming the chamber?

[larrym]

I too wonder about the compression loss and how it would affect performance, the guy that I was talking to locally is a nitrous  guy he is planning to build a couple engines small blocks and apply this to them to see how it works for him he seemed pretty excited so I figured I would see if anyone had tried it on a Buick. 

Moonshine and nitrous lol

[Steve Wood]

One cannot discount any idea without data.  Today's car run compression ratios that would appear to demand octanes well above today's premiums but a combination of combustion chamber design and modern ignition/fuel controls have made it possible.