By now most of you may know my little "project". For those who don't, I'll explain it again. I'll be running a 9A block, 95mm crank, Eaton M62, Weber DCOE 45s, and all the goodies involved in this setup.
Now that I've gotten that out of the way, I need to know a little about optimum valve sizes and clearances. The stock exhaust valves are 28mm and stock intake are 32mm. How far can I go before I run in to structural issues (8:1 cr / 20lbs boost)?
As well as valve size and clearance, I need to know the limits of porting on these heads. Specifics are welcome and very much appreciated.
I want as big of ports as possible as well as valves. In the 16v forum I've gotten very mixed answers. Someone there told me to go 28.5mm exhaust and 34mm intake. Now this doesn't make sense to me. Why would you want to make the difference greater? I would really like opinions from people with personal experience here. Don't care too much about the "theoretical" answers.
Thanks all... http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif
to let you knoone thing is that big valve heads are kinda rare.. the price most shops cost doesn't make it a good mod with all the blot ons around here.. big valve head are not a must do or a everyone can afford mod..
now to answer you question.. the bigger the valves the beeter the flow but not in all cases.. as long as you got enough flow going into the engine you wont loose power.. but don;t try to fit the biggest valves in it..
the sizes you listed sound about right.. but remember you intake manifold will still restict you air flow so you will still have a prob there..
i hope that answered or helped you out..
I'll be running a custom intake due to my Weber DCOE 45 carbs... Front mount of course with supercharger in rear of engine. Piping from supercharger around right (if looking from front) of engine to carbs out front. I guess I'll just go with these valve sizes. What about porting? Anyone with ported head have their flow rates available? Thanks.
quote:[HR][/HR]Not many real racers in here huh?[HR][/HR]
you have got to be kidding right? your not gonna get many answers from people with a statement like that. i did a mild port job on the exhaust side of my 2l 16v head before my turbo install. id rather spend money elsewhere and get my setup running at peak power, then go in and do some headwork to see where my gains lie. but for now, 11.9's will suffice for me.
Well, it doesn't seem people know their head flow rates... It's the most common question you could possibly ask when getting head work done. I just need one person to answer this question for me. Or, for a more simple question... Would a 1.8L 16v head be sufficient (port wise) for this setup? Again, my setup is listed at the top. Sorry if I've offended anyone with this but I'm not in to "bolt on kits". They're for weenies.
quite frankly, no one gives a sh!t about head flow rates when much more immediate and easier power gains can be found elsewhere.
why bother porting your head when your current setup isnt fully tuned? which i assure you with carbs, you won't have the most efficient fuel metering. when you get a fully programmable setup running that has been dyno tuned, THEN i would worry about headwork.
flow rate really don;t mean nothing.. no 2 heads will have the same flow rate.. turbo porting and supercharger porting is diffrent.. go to a real race shop.. i trust my shop to get me the most HP out of my engine so i don;t even bother to do flow rates.. you got guys like oversteervw who do porting them self so theres no need to do flow rates if you trust your work.. do yourself a favor and go to a real race shop and get some knowledge.. it not all about flow rates.. it about results..
to tell you the truth, i dont know any real flow numbers either. most people dont want to shell out the dough for a big valve, p&p, big name head. and the people that do their own headwork, in most cases, dont have a flow bench handy. so, for the most part, there isnt a market for worked heads. i looked at the major names
:TT, Autotech, & velocity. neither TT or autotech give any insight whatsoever to real numbers, and velocity doesnt even have cylinder heads on the site. those are the big names that i can think of when i always a hi-po cylinder head, and TT even has a flow bench, not sure about the others. i would be showcasing the fact that my product flows this much on this bench, but they dont. so for the price and the hassle, i didnt bother to find what they had to offer, i just did my mild port job and called it a day. most of the guys that i know with turbo 16v's have run stock heads, including me, and the et's range from 12.5 to 10.9 between the different cars. there is power to be had with a stock head, and there are racers doing it, that was my point. no hard feelings. later man.
Well, flow rates are very important where I come from (Chevy V8 crowd). Guess I'll just get a 1.8L head and do a nice port/polish and call it a day.
*edit* Got rid of a little "arrogance" http://****************.com/smile/emthup.gif
quote:[HR][/HR]Well, flow rates are very important where I come from (Chevy V8 crowd). Guess I'll just get a 1.8L head and do a nice port/polish and call it a day.
*edit* Got rid of a little "arrogance" http://****************.com/smile/emthup.gif
[Modified by HyKlas, 5:31 AM 11-27-2001][HR][/HR]
you arrogant bastard, how dare you ask specific questions!!!!!
personally, if i had headwork done they better tell me some flow numbers.
quote:[HR][/HR]flow rate really don;t mean nothing.. no 2 heads will have the same flow rate.. turbo porting and supercharger porting is diffrent.. go to a real race shop.. i trust my shop to get me the most HP out of my engine so i don;t even bother to do flow rates.. you got guys like oversteervw who do porting them self so theres no need to do flow rates if you trust your work.. do yourself a favor and go to a real race shop and get some knowledge.. it not all about flow rates.. it about results..[HR][/HR]
no flowbench (ie. doing it yourself) and trusting yourself dont matter, if it wasn;t done right, no bench, then its not right.
it is about flow........because it gets you results
There AREN'T many real racers/engine builders here, HyKlas. And I mean NO disrespect to the few that ARE here and contributing. This is a great site, but not the place for hardcore tech info. Lot's of pipe dreaming, internet convention spouted as fact, wheel questions, etc, but not alot of confirmed tech info.
For that motor you mention, you've gotta check out Justin's Hardcore VW site. Mostly a turbo/drag racing VW site, but a tremendous resource of folks actually making VERY fast VWs and I'd guess they will prove helpful. These guys can be a bit fickle as well, they don't accept everyone with open arms, but the power is there, results speak for themselves.
Re: Some 16v Head Questions..... (Andrew Stauffer)
quote:[HR][/HR]There AREN'T many real racers/engine builders here, HyKlas [HR][/HR]
there AREN'T many real watercooled racers/engine builders PERIOD. planning a forced induction setup doesn't exactly give you the right to criticize anyone else for not knowing anything. what's the use in trying to tune someone else's car over the internet when it isn't even running yet?
Flow #'s on the bench don't really mean jack either once you bolt that head onto the block the flow characteristics change. Look into it and you'll see what I mean. Some very successful racers don't bother flowing their heads cause they know what works and what doesn't
Hearing lots about Hardcore VW but The Site is down. I'm not really asking anyone to tune my car. I can do that myself.
Was just wondering if anyone running a similar setup could lend a thought or two. I guess not and that's no big deal. If someone does, great.
And like verboten said, flow rates are important to me, sorry. When i complete mine, I'll give you guys the low down. I'll have another spare head to try different configurations with as well.
If I've made anyone upset with my questions/comments, I'm sorry. Just trying to get a game plan down before I start throwing my money in the toilet. And if anyone else feels the need to throw in some information, have at it. Thanks again guys.
I'm a dork? No offense taken. "Dorkdom" is good to me.
As far as being a racer goes, maybe. Racing is *highly addictive*, not sure I can afford to truly take on yet another obssesive/compulsive disorder,er, I mean racing. Although the drag strip RULES for cheap(well...) fun and I'm considering setting the GTI up for hillclimbs next season. Here I go rambling off topic, another "threadjacking" in progress..............
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