Sydneykid Posted June 24, 2006 Share Posted June 24, 2006 (edited) Thats okay, but after speaking to some of the big tuners over in the States and Japan they all state that they remove the squish zones and use a custom piston to suit hence the purpose of this post since they arent reluctant to release what combustion chamber/piston design they use that allows high compression (9.0-9.5:1) with a fair amount of boost (1.5Bar) on pump fuel. And before anyone says Japan has better fuel the US doesnt and they still seem able to do it So what, how much ignition timing have they pulled out of it? How rich are they running it? What's the average power? What's the response like? In the US they chase the max horsepower number, they don't care about anything else cheers Edited June 24, 2006 by Sydneykid Link to comment https://www.sau.com.au/forums/topic/123350-custom-pistons-and-modified-combustion-chamber/page/2/#findComment-2282697 Share on other sites More sharing options...
markr34gtr Posted June 24, 2006 Share Posted June 24, 2006 why bother with all this stuff when rb 25 & 26 heads really only need a port job and the correct cam for your application... there are rb25 making 600 rwhp plus std head ported... & rb 26 heads ported making 1000 plus hp...leave alone what already works... cheers, mark. Proengines: Thanks very much for your input. I have drawn up some other chambers as you mentioned, I didnt quite understand the one about the V8 Wedge engines so I will wait for a clarification. If you can let me know which of the combustion chambers will work the best.My engine specs are RB26, high comp (9.0-10.0:1) running 1.5 bar and pump fuel to make 500awkw which is approx 800bhp. Chamber images: 1. Totally removed squish inlet and exhaust 2. Reduced squish inlet and exhaust allowing flat top piston due to piston entering the chamber where the squish was removed 3. Reduced exhaust squish with a Edyne style piston I greatly appreciate your's and everyon elses opinion Link to comment https://www.sau.com.au/forums/topic/123350-custom-pistons-and-modified-combustion-chamber/page/2/#findComment-2282721 Share on other sites More sharing options...
Turbine Posted June 24, 2006 Share Posted June 24, 2006 In our RB20DET GTS4, TurboX(Greg) spent hours removing any sharp machining edges and blending the chambers smooth by hand. The compression ratio drop is very small. We have had the boost set at 15psig so far with no dramas. Link to comment https://www.sau.com.au/forums/topic/123350-custom-pistons-and-modified-combustion-chamber/page/2/#findComment-2282732 Share on other sites More sharing options...
CRACKD Posted June 25, 2006 Author Share Posted June 25, 2006 Okay, well I dont want this to turn into a heated discussion. From the impression I am getting people in Australia dont modify the combustion chambers other than polishing and radiusing the edges. Is it possible to run 9.5:1, 1.5 Bar and Optimax Extreme? Link to comment https://www.sau.com.au/forums/topic/123350-custom-pistons-and-modified-combustion-chamber/page/2/#findComment-2283861 Share on other sites More sharing options...
Sydneykid Posted June 26, 2006 Share Posted June 26, 2006 Okay, well I dont want this to turn into a heated discussion. From the impression I am getting people in Australia dont modify the combustion chambers other than polishing and radiusing the edges. Is it possible to run 9.5:1, 1.5 Bar and Optimax Extreme? Don't know, never tried it. I do know 2 bar, 9.0 to 1 and Shell Optimax Extreme 100 ron is not a problem. cheers Link to comment https://www.sau.com.au/forums/topic/123350-custom-pistons-and-modified-combustion-chamber/page/2/#findComment-2284852 Share on other sites More sharing options...
NXTIME Posted June 26, 2006 Share Posted June 26, 2006 Avgas would be cheaper. Pity it's illegal (for street use) Link to comment https://www.sau.com.au/forums/topic/123350-custom-pistons-and-modified-combustion-chamber/page/2/#findComment-2285935 Share on other sites More sharing options...
dontfeelcold Posted July 8, 2006 Share Posted July 8, 2006 Don't know, never tried it.I do know 2 bar, 9.0 to 1 and Shell Optimax Extreme 100 ron is not a problem. cheers What setup was that on? RB31DET? Link to comment https://www.sau.com.au/forums/topic/123350-custom-pistons-and-modified-combustion-chamber/page/2/#findComment-2314359 Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now