Dish piston vs Notched

Joe DeMarzo · 08-02-2008, 01:00 PM

Which piston is better in a stock eliminator car and why? Does the notch piston/head make up for the compression that a dish psiton/head may have? Or does the dish piston create a hotter burn with a better head compression ratio? No specific combo in mind and everythinhg else being equal.

Thoughts?

Bub Whitaker · 08-02-2008, 10:10 PM

Ok Joe.. typically a flat top piston with valve reliefs and a quench type head/ SBC will make a better burn - more efficent power than the same head with a dish piston. Explain? I don't have a deploma from anywhere you just have to trust me... but if your refering to Stock Elim, then you don't have to worry cause I'm pretty confident that the HNRA \ I mean the NHRA has a handle on all the engine/ HP figures so as to level the playing field. He He

Joe DeMarzo · 08-03-2008, 08:34 AM

Bub, thank you for the insights, your word is good for me. I see some fast cars out there and try to figure out some of the performance related to combinations. One more question, if the cam is the same is the head with more compression better (even though it is a dish piston)? This one intrigues me, again thanks.. See ya soon, maybe at the Keystones we can finish this conversation.

Alan Roehrich · 08-03-2008, 08:48 AM

Joe, are you comparing a piston with a full round dish to a flat top with valve reliefs? Or are you comparing a piston with a full round dish to a piston with a reverse dome?

Provided the actual compression ratio is the same, there's nothing more efficient than a flat top and a decent chamber design (meaning the head has a chamber and both a squish side and a quench side).

A full dish is much less efficient, even with a good tight chamber, because the full dish prevents the squish and quench parts of the chamber from working.

A reverse dome is only somewhat less efficient, because the reverse dome design takes almost full advantage of the squish and quench parts of the chamber.

IF the head is the EXACT same head, and the cam is the same, and the ONLY difference in the compression is the design of the top of the piston, then the dish piston engine will make less power. Provided all else is equal as well.

rustbucket79 · 08-03-2008, 04:25 PM

The combination that has the most compression wins. You are restricted to the legal piston and head so changine either one to an illegal part is a big no no in class racing.

Mark Lewis · 08-03-2008, 06:24 PM

Most of the dish pistons you are talking about have a flat surface about .300 wide around the outside diameter of the piston and with about 10cc less combustion in the head that helps get the compression up more than the flat top with a bigger head.The camshafts are equal in factory specs. But you still have to maximize the whole combination.
Mark

Joe DeMarzo · 08-04-2008, 05:39 PM

Thanks for the insights, I appreciate the honesty. It will be helpful someday. Hope everyone has a win in their future....

08-02-2008, 01:00 PM	#1
Joe DeMarzo Senior Member Join Date: Oct 2002 Location: Mahopac, NY Posts: 666 Likes: 48 Liked 113 Times in 9 Posts	Dish piston vs Notched Which piston is better in a stock eliminator car and why? Does the notch piston/head make up for the compression that a dish psiton/head may have? Or does the dish piston create a hotter burn with a better head compression ratio? No specific combo in mind and everythinhg else being equal. Thoughts? __________________ Joe DeMarzo 1317 STK

08-02-2008, 10:10 PM	#2
Bub Whitaker Member Join Date: Feb 2005 Location: Dayton, MD Posts: 222 Likes: 0 Liked 1 Time in 1 Post	Re: Dish piston vs Notched Ok Joe.. typically a flat top piston with valve reliefs and a quench type head/ SBC will make a better burn - more efficent power than the same head with a dish piston. Explain? I don't have a deploma from anywhere you just have to trust me... but if your refering to Stock Elim, then you don't have to worry cause I'm pretty confident that the HNRA \ I mean the NHRA has a handle on all the engine/ HP figures so as to level the playing field. He He

08-03-2008, 08:34 AM	#3
Joe DeMarzo Senior Member Join Date: Oct 2002 Location: Mahopac, NY Posts: 666 Likes: 48 Liked 113 Times in 9 Posts	Re: Dish piston vs Notched Bub, thank you for the insights, your word is good for me. I see some fast cars out there and try to figure out some of the performance related to combinations. One more question, if the cam is the same is the head with more compression better (even though it is a dish piston)? This one intrigues me, again thanks.. See ya soon, maybe at the Keystones we can finish this conversation. __________________ Joe DeMarzo 1317 STK

08-03-2008, 08:48 AM	#4
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,097 Likes: 1,544 Liked 1,775 Times in 404 Posts	Re: Dish piston vs Notched Joe, are you comparing a piston with a full round dish to a flat top with valve reliefs? Or are you comparing a piston with a full round dish to a piston with a reverse dome? Provided the actual compression ratio is the same, there's nothing more efficient than a flat top and a decent chamber design (meaning the head has a chamber and both a squish side and a quench side). A full dish is much less efficient, even with a good tight chamber, because the full dish prevents the squish and quench parts of the chamber from working. A reverse dome is only somewhat less efficient, because the reverse dome design takes almost full advantage of the squish and quench parts of the chamber. IF the head is the EXACT same head, and the cam is the same, and the ONLY difference in the compression is the design of the top of the piston, then the dish piston engine will make less power. Provided all else is equal as well. __________________ Alan Roehrich 212A G/S

08-03-2008, 04:25 PM	#5
rustbucket79 Junior Member Join Date: Aug 2004 Location: Canada Posts: 45 Likes: 0 Liked 0 Times in 0 Posts	Re: Dish piston vs Notched The combination that has the most compression wins. You are restricted to the legal piston and head so changine either one to an illegal part is a big no no in class racing.

08-03-2008, 06:24 PM	#6
Mark Lewis Member Join Date: Apr 2006 Posts: 344 Likes: 63 Liked 207 Times in 44 Posts	Re: Dish piston vs Notched Most of the dish pistons you are talking about have a flat surface about .300 wide around the outside diameter of the piston and with about 10cc less combustion in the head that helps get the compression up more than the flat top with a bigger head.The camshafts are equal in factory specs. But you still have to maximize the whole combination. Mark

08-04-2008, 05:39 PM	#7
Joe DeMarzo Senior Member Join Date: Oct 2002 Location: Mahopac, NY Posts: 666 Likes: 48 Liked 113 Times in 9 Posts	Re: Dish piston vs Notched Thanks for the insights, I appreciate the honesty. It will be helpful someday. Hope everyone has a win in their future.... __________________ Joe DeMarzo 1317 STK

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode