And the compression ratio was....

The other day Paul dropped by and measured the compression ratio on my engine. Was it low enough for turbos to be fitted without changing heads or so high that I need dodgy fuel to make the car run? Well, I will state that we got a boring 9.5:1 and you can decide for yourself if my times are plausible with a compression ratio such as this! You guys with fancy smancy engines should do better! And 9600 rpm, who would fall for that?

Malcolm


[ November 12, 2002: Message edited by: Malcolm M ]

Wasn't it 19,600 rpm?

But how big is the motor?

Lots of aircraft engines in WWII didn't have such high compressions either, but 27 liters is hard to argue with!

Ron

Hi Malc -
Went for the 'honest option' then - I agree with Ron - there ain't no substitute for cubic inches and with one or more superchargers - all the better!

Hi Mike - I seem to remember you drive a rather quick turbocharged V8 - what compression does it have and how much boost? - either way flaming quick as I recall!

With excellent fuel control and engine control (knock sensing with electronic retard) you should be fine at 9.5:1. I know there aren't many OEM motors that are blown with 9.5:1 but you'll be fine, especially if you keep the boost down. I used to run 22lbs on a motor at 8.7:1 and it was fine with excellent gas and proper timing.

R

Turbo's? No thanks, don't like them from my experiences so far. Also makes the car too technical for my oily rag techniques!

Was discussing the compression situatioon with Dave Milham who is planned on rebuilding it for me later this year. He doesn't think that the compression should be as low as stated taking into account the parts fitted to the engine. I shall have to get him to measure it for me also when he has the engine. However it doesn't matter as I ain't changing anything apart from the worn out bits so will keep whatever compression ratio I have, whatever it really is.

Malcolm