Mazda Rotary Club

General => General Technical => Anything Engine/Performance/Tuning related => Topic started by: Spaarks on September 17, 2011, 04:15:09 PM

Title: Compression Results
Post by: Spaarks on September 17, 2011, 04:15:09 PM
Hi guys,

I\'m currently in the market for a Single turbo, 3rd gen and wanted to check a few things before I rush in and make a purchase. :wiggle

Please correct me if i\'m wrong but when looking at compression results is it right that...

* The closer the results are together, the better. (0.2/0.4 bar difference)
* 8.0\'s for a new engine
* 7.0\'s for a good engine
* Anything below 7 could cause problems?


I also read somewhere that if a 13b has been heavily ported compression results below 7 aren\'t uncommon? Is this true? I ask this because i\'m currently talking to a guy who\'s running a T78 on a ported 13b with water injection, all done by dragon performance. He said not to expect 7.0\'s all round as the engine has been heavily ported. :3Confused

Can anyone give me some advice on this please?

Thanks alot  :cheers

Sam
Title: Compression Results
Post by: jamison1982 on September 17, 2011, 04:21:04 PM
ignore my comment mate :) i deleted it as it was totally irrelevant
Title: Compression Results
Post by: Spaarks on September 17, 2011, 04:46:19 PM
Quote from: jamison1982;788834ignore my comment mate :) i deleted it as it was totally irrelevant

haha no worries!

Can u give me any information regarding the results to expect anyway?

sam
Title: Compression Results
Post by: jamison1982 on September 17, 2011, 05:13:43 PM
I can soon as my street ported t78 is being tested by reworx as I\'m selling it
Title: Compression Results
Post by: Edd1Ninety9 on September 18, 2011, 09:04:13 PM
Ridiculous.
Title: Compression Results
Post by: RyanT on September 18, 2011, 10:46:53 PM
Have you just posted this everywhere :D. I have no idea why but it seems when you port a engine the compression drops. I don\'t understand why as I thought that pressure inside a chamber would be the same regardless of of volume of air. So I don\'t really understand why it does but it seems to be the way.
Title: Compression Results
Post by: Jit on September 18, 2011, 11:09:42 PM
My experience is thats not true. Ive done many a large ported engine and pulled really good numbers. Theres just too many variables but i dont really beleive that port sizing is one of the major ones.