Don't worry too much about exhaust ports / valve sizes unless it's radically restrictive in std form. Generally the manufactures arnt stupid...all the recent VW/Ford/Peugeot/ heads I've tested have more than enough exhaust flow for the std inlet...an exhaust flow/valve size article is coming soon.
Some more crossflow development... As the picture a couple of posts back show, there was a dip in the curve of the inlet flow. An isolated area like that can sometimes point toward some form of turbulance, so thats what I went on the hunt for...and I had a fair idea where to look. The back of the inlet valve had the smallest of lips where the valve back joined the seat contact area... it could hardly be felt but I could see it... if I could then so could the air path. Some light fettling by spinning the valve in a drill & dressing the lip with a stone gave a better blend into the seat. So, back to the flowbench... ... and no more dip! As an added bonus the peak flow has come up a touch from the previous best of 98.9 to 99.2cfm... condsidering a conventional 42mm valve head makes 103cfm, 13 up from a good normal 40mm head, the crossflow looks to have the potential for some serious flow. And below, the journey so far from std 39.5mm crossflow in green, to best to date 40mm crossflow in white, with a good conventional 40mm head in blue... All we have to do now is get the exhaust flow up to scratch.... guess what's been happening on the JMR workbench today...
Thanks Mike. Your MK1 is looking very good... I dont get much chance to flick around the various sections these days but caught a glimpse of yours... looks great!
No probs at all! Bin the old k-jet to start with, we'll give the head some TLC and you'll be rocking around 180 to start with...then your gunna need some forged pistons to cope with the c.r to run a proper cam, and the valve train to cope with it.
Please no-one take offence but the cost vs the bhp gain just wouldn't do me any justice and working on a low wage doesn't help. Would love to do the work but it would mean the car would probably never get finished.
That's why it's taken me nearly 5 years to get all the bits together for my engine Mike.....labour of love but I am determined to have it done next year
I'll have to stick with 165bhp for a while yet lol but the JMR work looks amazing with it's results, would be interesting to see what could be done to a TSR pack C head as i never went for their D head.
Don't blame you at all Mike...engine tuning isn't cheap, and on a project like yours it needs to look right too. So get saving for a nice down draught head on t/b's! As for the head...yr fine on what you have...yr not looking out on anything. .it can be upgraded past the other spec with ease...just inlet valves and re porting.
Never a truer word spoken! Having to run OEM stuff in our race series is expensive enough, trying to extract all you can from basic mods with strict regs adds up quickly! Watching your development with the utmost respect. Not only the right numbers, but more importantly putting those numbers to good use with the results to back them up... On another note! I dont suppose your 020 gear linkage system would work on a Mk2 Scirocco? It looks the t*ts.
Another cost to take into account when changing things around is engine management. I could always knock down my engine head costs with some JMR advert decals on my car .
Restricted regs can sometimes be as or more expensive per mod as you have to work extra hard for very small gains. Thank you very much...one does try... As for the linkage. .it's only designed to fit the mk1, but, if the bulkhead / floor pan dimensions are identical then it may fit. If a scirroco linkage is identical to a mk1 Golf there's a good chance it'll go. The only issue then could be the seating position. .Scirroco being more laid back.
It is indeed...not cheap whichever way you look at it...plus plumbing the system. .again not cheap if done correctly. We can certainly talk about that Mike...Im fairly flexible.
Hey Jason, dont want to tell you how to suck eggs your the expert, im a novice lol, was having a dig on the net and came across the somender-singh groove theory :- http://somender-singh.com/content/view/7/31/ A few people have mentioned it on vortex, a few have tried it. Do you think its worth a shot? What are your thoughts?
