dr gary turner
Well-Known Member
- Joined
- Dec 25, 2004
- Messages
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What are the pros and cons of a Flat Top piston vs. a Dish Top piston??
Honestly, the one you work the hardest tuning. IMOWhich one produces the most power??
I found out my self that seem compare two different : best flat top piston most power and high nitro . The dish top piston tricky power ( depend on low or high nitro also change measure shims ) and best turbo plug button if you use std plug button but if see glow coil pull out sometime happenWhich one produces the most power??
It’s also used to cool the top of the piston with the fuel charge to prevent burning a hole in the piston
If I remember the first Quincy Loopers (Alky outboards) had flat top pistons and went to a slight dome to prevent burning a hole in the piston.Yep, more surface area.
If I remember the first Quincy Loopers (Alky outboards) had flat top pistons and went to a slight dome to prevent burning a hole in the piston.
What are the pros and cons of a Flat Top piston vs. a Dish Top piston??
In theory , fuel burns better in a spherical combustion chamber. The dished piston should burn the fuel better.What are the pros and cons of a Flat Top piston vs. a Dish Top piston??
It’s also used to cool the top of the piston with the fuel charge to prevent burning a hole in the piston
Looks like an attempt at variable valve timing. LolHa! Remember this one John?
For my money I'll take the flat top, why thin the crown right where it's hottest?
A DISHED PISTON IS NOT DOMED. SHOULD I REPEAT THIS AGAIN ? IT CAN BE DOMED AND DISHED BUT THAT IS NOT WHAT THE ORIGINAL POSTER ASKED ABOUT. TOP FUEL DRAGSTERS RUN 100% NITRO AND DISHED PISTONS USUALLY BECAUSE THEY HAVE MADE MORE POWER WITH THEM THAN FLAT TOP. ALL BECAUSE IT BURNS THE FUEL BETTER/FASTER.This is one of the areas I am looking at now and I have sought some advice. I had a conversation with Peter Halman (designer and builder of Halman special F2A control line speed engines) This was part of a much larger conversation and not specifically about piston design but engine design in general so was just a passing point on piston design rather than a detailed analysis of why.
"A domed or chamfered piston is stronger than a flat top piston and is important when run for long periods as in circuit car racing, this is as important as maximum power. Flat top pistons give more power as the combustion force is transmitted more directly straight to the crankshaft."
I feel that the design of the piston is dictated by the application, actually, a lot of the engine design is. Porting design, material choices, etc, Let's not get into liner taper for different applications as well....
My point would be that it depends on the application, what is used for? - work back from there.
The basic rules appear to be that a domed piston is better suited for longer, high-loaded applications, and flat-top pistons are more suited to shorter runs where ultimate power is the main priority and where you are unlikely to go beyond the thermal capacity of the components.
The amount of power difference between the 2 will be small but may be important if you are trying to eke out the last %
Ricky
Calm down Jeff, no need to shout....A DISHED PISTON IS NOT DOMED. SHOULD I REPEAT THIS AGAIN ? IT CAN BE DOMED AND DISHED BUT THAT IS NOT WHAT THE ORIGINAL POSTER ASKED ABOUT. TOP FUEL DRAGSTERS RUN 100% NITRO AND DISHED PISTONS USUALLY BECAUSE THEY HAVE MADE MORE POWER WITH THEM THAN FLAT TOP. ALL BECAUSE IT BURNS THE FUEL BETTER/FASTER.
I was thinking here of the NR21DD’s that Doc and I run that have a bevel and then a slight dish in the center of the raised part of the piston.It’s also used to cool the top of the piston with the fuel charge to prevent burning a hole in the piston
They are also running super chargers which is also a significant factor in their piston designA DISHED PISTON IS NOT DOMED. SHOULD I REPEAT THIS AGAIN ? IT CAN BE DOMED AND DISHED BUT THAT IS NOT WHAT THE ORIGINAL POSTER ASKED ABOUT. TOP FUEL DRAGSTERS RUN 100% NITRO AND DISHED PISTONS USUALLY BECAUSE THEY HAVE MADE MORE POWER WITH THEM THAN FLAT TOP. ALL BECAUSE IT BURNS THE FUEL BETTER/FASTER.
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