Compression ratio question for EU members
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,164
Likes: 7
From: Beringen
Compression ratio question for EU members
Looks like I will be getting 10.83/1 CR on my engine. The gas I will be using will be EU 98 octane.
Anyone in use this gas in combination with a CR close to 11/1 ?
Anyone in use this gas in combination with a CR close to 11/1 ?
Drifting
Joined: Jul 2005
Posts: 1,623
Likes: 29
From: The Netherlands
Not yet, but I had my combustionchambers enlarged by Post & Dros to get under 10.5. Hoping to still be able to run 95 octane, but guessing I'll end up using 98 (at $2,35 per liter 
).
Cast or aluminum heads? In general compression can be up to 1 point higher with aluminum heads than with cast iron ones.
).Cast or aluminum heads? In general compression can be up to 1 point higher with aluminum heads than with cast iron ones.
Last edited by worship79; Jan 31, 2012 at 03:00 PM. Reason: Added info
Race Director
Joined: Sep 1999
Posts: 11,361
Likes: 383
From: Plano TX
When building a motor you can safely assume that Euro 98 is equivalent to US 93 octane. So follow the advise for US 93 octane (premium gas) builds and you'll be OK.
10.83:1 CR: Hope you have aluminum heads and a big cam.
10.83:1 CR: Hope you have aluminum heads and a big cam.
Advanced
Joined: Oct 2007
Posts: 59
Likes: 0
From: Hockenheim
FWIW, I run my stock L46 (11:1 compression) with 98 EU-octane.
When setting the timing as per Lars' spec (16 degrees advance it idle and 30 degrees above 2500 rpm, without vac) I have some pinging, so I backed up 4 degrees and it runs fine now.
Carsten
When setting the timing as per Lars' spec (16 degrees advance it idle and 30 degrees above 2500 rpm, without vac) I have some pinging, so I backed up 4 degrees and it runs fine now.
Carsten
Melting Slicks
Joined: Jan 2003
Posts: 2,877
Likes: 13
From: Doha
St. Jude Donor '08
So the octane number is not a international standard?, if not, then how can I know whats my local octane equals to the US octane?
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
98 RON is equivalent to 92-93 AKI.
Melting Slicks
Joined: Jan 2003
Posts: 2,877
Likes: 13
From: Doha
St. Jude Donor '08
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,164
Likes: 7
From: Beringen
Engine has a higher dwell time at TDC, which could work against me as well, since pressures would be higher because of that.
I still haven't touched the chambers though. The boresize allows a considerable amount of deshrouding if necessary.
Trying to figure out which way to go.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,164
Likes: 7
From: Beringen
My old engine had a piston with a slightly smaller dome, 3 cc versus the 4 cc of the autotec. My old engine was around 10.73/1 and didn't know. However I'm not sure what the results of the itb's will be since these will improve cylinder filling. Cam timing was also unkown for that engine.
