thicker headgasket - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to   Members

Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by:

LinkBack Thread Tools Search this Thread
Old 10-02-2009, 01:54 PM   #21
Junior Member
Join Date: Mar 2009
Location: maine
Posts: 224
Total Cats: -1

Originally Posted by neogenesis2004 View Post
A thicker HG does lower your compression regardless of application. The issue is in the quench area of the combustion chamber and piston. At TDC the outside edge, exhaust and intake sides, of the CC and piston have a near contact area that pushed the combustion into the middle of the CC causing it to tumble. This reduces risk of detonation and improves combustion efficiency. When you install a thicker HG you eliminate this effect, reducing combustion efficiency.

On the flip side, because it lowers your effective CR you are able to run more boost which can make up for that loss in combustion efficiency. I think that 2 engines with the same CR, one with a thicker HG and one with dished pistons, the one with the dished pistons will be able to either run more boost before detonation or make more power at the same boost. I have no empirical data to back up this view point however.

That said, a quick and easy way to reduce CR and run more boost is a thicker HG. A more ideal way however is installing dished pistons. In direct application to our motors, you can make enough power with stock pistons to bend/break stock rods. Therefore it is a little bit dumb to install a thick HG on a b6/bp motor in order to run even more boost/hp. If your plan is to run more boost on our motors to NEED to run a thicker HG, you will also need to install forged rods. Which in this case you would be stupid to not install dished pistons at the same time, cast or forged.

I hope that helps. I rarely feel inclined to type this much for someone I don't know.
good write up. I will say though from what i have heard in the past from the honda ricers way back when, is that the science behind the head gasket was to lower compression to put less strian on the connecting rods. I personally don't see a 9:1 comression ratio high enough to warrent this mod. On a bp engine even if you did drop the compression to say 8.5:1 i still think the rods would go before the pistons. The one internal mod that is needed to break 250whp safely is rods. After 280-300whp pistons. thicker head gaskets are just a cheap way to maybe squeeze an extra pound of boost out.
94blackmx5 is offline   Reply With Quote
Old 10-02-2009, 02:58 PM   #22
Junior Member
Join Date: Aug 2008
Location: MD/DE/PA
Posts: 337
Total Cats: 0

Originally Posted by 94blackmx5
.... honda ricers ... science ...
Non sequitur.
the_man is offline   Reply With Quote
Old 10-02-2009, 03:43 PM   #23
Elite Member
Join Date: Feb 2008
Location: Victoria, BC
Posts: 2,322
Total Cats: 12

Originally Posted by magnamx-5 View Post
The only limits are those set by detonation
I'm sorry, but the only limit is yourself.
dustinb is offline   Reply With Quote
Old 10-02-2009, 04:02 PM   #24
Junior Member
Join Date: Aug 2008
Location: MD/DE/PA
Posts: 337
Total Cats: 0

Been a long time since I saw a link to Zombo.
the_man is offline   Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
Mazdaspeed 2.0L C-Spec ITB motor w/ accessories graexodus Miata parts for sale/trade 9 10-25-2015 04:34 PM
Looking for copper jankymiata Engine Performance 23 09-12-2015 07:07 PM
Head decking & how it effects compression ratio, & timing thesnowboarder Engine Performance 15 09-03-2009 11:21 PM
Rebuilding my 1.6 bengxe Engine Performance 4 03-06-2009 12:56 AM
OE headgasket question fahrvergnugen Engine Performance 9 09-16-2008 12:02 PM

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -4. The time now is 05:11 PM.