Reverse Dome vs Flat Tops in an NA Build
07-21-2015, 07:55 PM
#1
Reverse Dome vs Flat Tops in an NA Build Just spurring some debate...
In an Naturally Aspirated motor, I realize there is some debate as to whether a dished piston is less than ideal for the flame front due to a lack of a quench area. However, the reverse domes with quench pad areas that mimic the combustion chamber seem like a good compromise. Does anyone have any data or real world experience with the difference in power (if any) between a reverse dome and a flat top?
If you're following my other current thread, you'll see that I'm considering using small bore heads with a tighter combustion chamber on a bigger motor. I want to know if it'd be worth it to soften the chambers or simply run a reverse dome piston to get compression where I want it.
In an Naturally Aspirated motor, I realize there is some debate as to whether a dished piston is less than ideal for the flame front due to a lack of a quench area. However, the reverse domes with quench pad areas that mimic the combustion chamber seem like a good compromise. Does anyone have any data or real world experience with the difference in power (if any) between a reverse dome and a flat top?
If you're following my other current thread, you'll see that I'm considering using small bore heads with a tighter combustion chamber on a bigger motor. I want to know if it'd be worth it to soften the chambers or simply run a reverse dome piston to get compression where I want it.
07-21-2015, 10:22 PM
#4
When the Busch series went from V6s to 9:1 V8s...they did not use a 76cc chamber and a flat top because the flame travel was smooth and even.
They quickly used a reverse dome and like 38cc chambers with 18 and then 15 degree heads
This combo magnified the compression turbulence and lowered the BSFC numbers
07-22-2015, 05:10 PM
#7
What heads are you considering for a small-chamber? I'm certainly not that knowledgable on the options out there, but I haven't stumbled onto any small chamber LS heads, outside of the C5R head. 
What are the options for this type of combination? It's funny you started this thread, because I have wondered about this exact topic myself...
What are the options for this type of combination? It's funny you started this thread, because I have wondered about this exact topic myself...
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07-22-2015, 05:59 PM
#8
Running my heads ~ LS6 @ 62cc on a 418 with an 8cc reverse dome. Certainly not the same as a 38cc with a 20cc reverse dome or whatever NASCAR runs. But enough to push 12:1 CR... which is about the limit I'd want to mess with on 93 octane.
07-23-2015, 07:55 AM
#11
Usually the opposite. A dish has little to no quench area. Not really a big issue with FI as the boost aids the mixing.
I'd have to say that a reverse dome logically makes more sense in your case Jake. I'll probably be in the same boat once I swap out my bottom end. I'll probably have the Mamo 220's for a long time.
I'd have to say that a reverse dome logically makes more sense in your case Jake. I'll probably be in the same boat once I swap out my bottom end. I'll probably have the Mamo 220's for a long time.
07-25-2015, 11:02 AM
#12
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Usually the opposite. A dish has little to no quench area. Not really a big issue with FI as the boost aids the mixing.
I'd have to say that a reverse dome logically makes more sense in your case Jake. I'll probably be in the same boat once I swap out my bottom end. I'll probably have the Mamo 220's for a long time.
I'd have to say that a reverse dome logically makes more sense in your case Jake. I'll probably be in the same boat once I swap out my bottom end. I'll probably have the Mamo 220's for a long time.