I have down my cams, i was thinking in increasing the compression ratio of my clio 1.6 16V, so how many millimeters i have to reduce to my cam or the recommended to increase a litlle bit my compression ratio???, i was thinking like reducing 0.7 millimeters, thanks for your recommendetions.
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Reduce cams CR
- Thread starter clio_manu
- Start date
TVR Cerbera
why?
TVR Cerbera
Increasing CR is nearly the last thing you mess with when tuning. skimming the head or decking the block is a lot more involved than "i was thinking like reducing 0.7 millimeters"
Yeap i know all that stuff like clearance between the valve and the piston, and if you reduce the dead volume that is the volume between the piston and the roof of the cam you can increase the CR, so i was just asking if you know the new CR that i would have if i reduce 0.7 millimeters for say an example or if you have experience on that. Im just looking for suggestions, thanks.
ClioI Ph.3 1.6 16V
Reducing the CR by skimming the head isn´t really professional, better use high compression pistions like they are offered by wössner http://www.woessner-kolben.de/english/indexenglish.html
By skimming the head you also change the valve timing because you reduce the distance between the crank wheel and the cam wheel, but the tooth module of the cam belt keeps the same....
yes but presumably the cams will be higher spec, and so require specific lift at TDC figures as set when fitting.
There isnt really anything wrong with skimming the head, your not going to gain a load of Cr from doing it, its just a means of tweaking it even if you have high comp pistons.
As for the calcs, you dont need any tools really. if you can measure actual compressed volume, then thats best...if not just back calculate from std Cr to obtain it, alter the figure to suit a reduction from skimming however much you want, then re-enter this figure to obtain a new Cr.
My point was: yes this is an open forum, that doesnt mean that any info you gather from it is full and sound, therefore I wouldnt use it as a firm basis for building an engine. Do it yourself and you know its right.
There isnt really anything wrong with skimming the head, your not going to gain a load of Cr from doing it, its just a means of tweaking it even if you have high comp pistons.
As for the calcs, you dont need any tools really. if you can measure actual compressed volume, then thats best...if not just back calculate from std Cr to obtain it, alter the figure to suit a reduction from skimming however much you want, then re-enter this figure to obtain a new Cr.
My point was: yes this is an open forum, that doesnt mean that any info you gather from it is full and sound, therefore I wouldnt use it as a firm basis for building an engine. Do it yourself and you know its right.
LY 182
got to admit i agree completely with stan.
if i were to tell you it was 1mm, you went away with that information skimmed 1mm off the head bolted it all together started it up and it bent all your valves you would be pretty anoyed wouldn't you.
i think the only answer you are going to get mate is measure it yourself.
even if you get an answer from a respected tuner all engines vary - and ask any tuner and i gaurentee they will tell you they measure and calculate for each engine
Stan all my engine is stock, so im running with the stock pistons stock spring valves all the parts stock. You are saying that i have like 4 mm of clearence between the piston and the valve???, if you are sure about that i wont have problems reducing 0.7mm no???, thanks.
Yeah men i can reprogramme the car's computer, i think that there are no minimal gains with the things that i'm doing, any of you guys have an idea of the degrees of timing that you run for example a superchip???, any of you have a modified map for the 1.6 16V that can share with me??, thanks.
Clio Sport 172 ph1
