Like yr all waiting in anticipation !... Well, a price structure and announcement will be going up on my own website in due course as soon as my webman has sorted a new section for me. I've tried to avoid the "please buy a head from me" route on here for a couple of reasons... 1... Mike already runs the group buy, so I dont really like steping on toes, and to be totally honest, there's no way I can do them for those prices.. the machining and the cost of the guides cost "me" almost the same as a shed head (the pre vat price that is). They are however, I feel, as good as many on the market, flow bench developed (and I dont cheat by using big bore adaptors so my flow is real world), but still work out cheaper than most you'll see at retail. 2... Advertisers may not like paying for space on here only for someone to come along a take work from under their nose. I am more than happy to chat about any individual requirement via PM though, and some may not want the world and his wife (or just the wife!.. ) to know what or who they're buying from. Does that make sense ? In the next development I will look at what flow I can get from minimum mods. I have a lot of data that suggests what direction to go in, and in some cases a more cost effective head could come from it, i.e those on standard inlet manifolds may work well enough with less work, so could work out a bit cheaper. What I did find is it's like most engine mods, a combination of mods to make the whole. Porting on it's own without the valve seat work only gains flow at the peak lift zone, while just valve modding work helps right off the seat but the advantage fades as the lift goes up (which makes sense really), the correct final seat work brings it all together and add's a substantial chunk... but I'd like to see how the seat work alone effects things, and further valve shape design, oh and big valve conversions... I'm not done yet. But for now, I feel the current spec does the job, and will be spot on for it's application.
I'm all for people having a choice, and I think this thread stands as a good study in head modifying, with great, tangible results. Also, you're in a different part of the country from the Shed, so that could work too. I also hear very good things about the head work that Vagobonds does - I haven't seen one close up, but people whose opinion I respect rate them very highly. If the club members and forum users have a choice of suppliers, I think that's healthy. I'll drop you a PM about Club GTI's commercial advertising rules. As you pointed out, we need to try and keep a level playing field between the different people in this sort of business.
Here is my 2 pence for what its worth. I would look at a shed head as a great value reconditioned head, not a performance head (but please bare in mind I have only had one flowtested - he might have had an "off-day"). For performance heads, buy one where you can get comparative flowbench figures - then you know what you are buying into.
well after starting this thread and then not actually flowing my head for a month. i started it today. the bench was a superflow sf600. on bare ports i got 134.44 cfm intake and 122cfm exhaust on one cylinder. and the other 3 i got 130.05 intake and 117.76 exhaust. obviously the difference is vast and i think this was because the first test i had a leak. im testing again tommoro with valves at different lift heights. see how it goes when im all finished i will post full results. unfortunatly i dont have originals because i wasnt at uni wen i started porting. how do you back cut the valves???? and what tools are needed cheers ed [/IMG] [/IMG]
I don't think it's that simple. I'd like to see results on a dyno to be sure. Port flow is one thing but it still needs to have enough velocity to work in normal driving. Horses for courses maybe?
Good start. I had 137cfm when I first tested on a bare port, never tested the exhaust at that point. To be honest the real test starts to come when the valves are in, a hole with no valve is going to flow fairly well, when you fit a valve the important area of the seat shapes come into play as the air obviously has to pass through them. It looks like in the pics that you hav'nt done any work there yet so that is where you need to concentrate next. To back-cut the valves a seat width will need to be taken into account, than an angle of 30 degrees (or just the sharp edge to start the development off) needs to be made between the top of the seat and the back of the valve. Allow a little extra at the top of the seat to gently blend the seat into the back of the valve or you'll end up with a sharp edge again. The whole porting exercise will only come into play once the seats are cut in the head and the final blend is done, just backing off the valves wont be enough as it helps in one area but makes it worse in others as it's changing the air direction and forcing it into the un-shaped standard seat. Good luck with it, and nice flow bench, your luck to be using that.
Indeed, I'm going to try and look at building up a "dyno donkey" engine to do some back to back tests. It'll probably be a standard engine on carbs for simplicity as rigging up K-jet or Digi would be a mission mounting airbox's and fuel systems (so that'll be a good test on it's own) then I'll swap the heads. I expect it'll be a 16v first as I see it as the more anticipated option, though it'll depend on what I can build up from bits, though it wont be for a couple of months. I expect the 2 ltr 16v that the current head is going on will be running before that though, so that'll give an indication of what to expect. I'm sure I'll find time to keep you all posted.
Makes sense - a high pressure fuel system makes a big mess when it goes wrong too! I've got a spare shed head from my old car sitting, if you need one to compare.
If it helps I've got a ported TSR "027" head (with the larger inlet ports) which can be used in a comparison. Its going to be while before it finds its way on to my 9A rebuild...
could someone pm some prices to do an ABF headly. to crack around 200hp. looking in your direction hillclimber Cheers
Mmm... could be interesting. I think I can borrow one locally to save sending heads around the country, but if not I'll bare that in mind Mkie, thanks.
Blimmey, it's like being back a college having lots of knickers thrown at me... not that I ever did of course... Yes, two heads from the same source would be a good "shootout", though there's bound to be some differences. I'm a little weary of testing shed heads with so many people running them and there being issues (or they maybe superior, in which case, fair play), the man does make a living from them after all. As mike say's I doubt the larger initial port will show up much.
Jason, did you record the Std exhaust figs into a table, or did I miss it? Reason I mention was whilst shunting threads about earlier, I stumbled over a 2005 thread, info below - possibly a worthwhile comparison? Jim Kniston-origins, and a KR head I assume.
