I'm looking at the chart right now... The ABF is up on flow at all points (this is just inlet flow at the moment), they balance out in mid flow then the ABF picks up again. I'll try and scan it in later. The ABF is indeed an 051 103 373 D casting, the 9A is the same number but has an "A" stamped after the 373 rather than the raised "D" on the ABF.
Right, here we go... Ignore the comments, I just overlayed the two tests and deleted the various lines to make it easy to see what we're talking about, the comments are from various tests on the tests.. if that makes sense, but all we're looking at here is the std head flow for both an ABF & a 9A. The ABF is the dark blue line. The figures shown are true to the graph, the top set are the ABF test, the lower set the 9A. Enjoy & comment away.
Certainly v. interesting. Damn, the temptation to add a load of flow data to the bulging 16v outputs thread!
Good stuff Jason, I had not seen the 051 9A casting tested before. Just need a standard 027 now to complete the set...
Cheers Neil. I best dust off the one I have here then and get it on the bench... If they're being ported tho, it does'nt matter what base casting you start with, at least between the 9A & ABF on the inlet, tho the exhausts are less critical.
[YOUTUBE]wOeVvYKkN-s&feature=player_detailpage#t=411s[/YOUTUBE] Watch from 6:51 , or just click here>>>wOeVvYKkN-s&feature=player_detailpage#t=411s You won't get much power then the rod/stroke ratio is bigger than 1.4 What everybody forgets in those square, undersquare and oversquare engine games that as bigger the bore, the bigger valves you can fit. Subaru has bore of 95mm and uses 36mm intake valves (it in combination with huge intake runners, bad designed exhaust and way over too big turbine hot snail killed engine performance in low and mid range rpm). And if you want to argue click here>>>wOeVvYKkN-s&feature=player_detailpage#t=411s
Nobody has forgotten this. Please carefully read about the racing VW/Audi engines discussed previously: http://www.clubgti.com/forum/showthread.php?t=187653 http://www.clubgti.com/forum/showthread.php?t=220777
Hi Awesome thread! Could the flow diff's between the 9A and ABF be due to the shorter valve guides? I wonder what would happen if one fitted ABF guides to a 9A? Bothe heads stock std ? Anyone care to test this? Or maybe it has been done on a std head before?
Hi Here in South Africa we never got the 9A nor the ABF. We only had KR 102kw from1986 to 1990 and we had the 2.0l AAL between 1990 to 1994. The AAL was rated at 110kw(150H) too but was not fitted with the ABF head, although it too had a small port head with the 50mm runners. Note also that AAL's were CIS basic kjet. (No emission requirement needed here) Hence the reason for asking about the shorter valve guide comparison!
It has.. and the answer is very little difference. The flow certainly is'nt because of guide protrusion... I've tried them at various levels and with none at all, and theres less than 2cfm between a guide protruding as normal and one flush with the roof... but this would wear out very quickly due to lack of support.
Spitze, What head are you referring to as "small port" and what were the valve sizes? - - further, while the 16v 50mm runner intake is well known, what were the other AAL specs please? eg actual compression, as compared to dodgy VW marketing specs - - cam p/n's if at hand - - was ignition timing integrated into the fuel ecu or was there a separate module? p/n's please? - - throttle body size & p/n? - - fuel pressure? - - in short anything to shed light on component and tuning differences compared to the ABF
Mr H, Thanks for this feedback - - am also most intrigued re exhaust port flow, which some of us believe affects performance in subtle ways not necessarily shown by torque readings - - would love to see your comparative figures as distinct to those produced from a different flowbench
I've got some before an after 16v ported exhaust flow figures somewhere... in fact I'm sure I've posted them somewhere... but I'll dig them up again. Regarding exhaust flow relating to power... I've not done any specific testing in that area on the 16v, but on the 8v I dont believe big flow is any real benefit. I've flow tested high flowing exhaust ports that have made no more power on the dyno than lesser spec ports. My own ex hotrod head has a low exhaust flow ratio compaired to the inlet and yet makes the same power as a higher flowing one. When I port a head it's just natural to try and get the best flow on both the inlet and exhaust, but the MOST important side is the inlet... fitting bigger exhaust valves without bigger inlets or trying to get very high exhaust flow ratios compaired to the inlet is for the most part not needed...at least on the engines I've tested to date. I'll get some of the results up when time permits... which there is'nt a lot of at the moment... but as soon as I can I will.
Mr H, Agreed, intake undoubtedly more important - - however the flow ratio remains contentious Have sent personal email rather than hijacking the thread
Recieved thanks... will get back after the weekend. As a note... there are many suggested flow ratios between inlet and exhaust. Those in the know have quoted anything between 70 and 80% as the "must have" exahaust flow when compaired to the inlet. I've seen race power from 8v engines (over 100hp per litre) with exhaust flow as low as 62% on more than one occasion... make you think does'nt it.
Bring this topic back up, I'm having my bottom end done. Current set up is: Jenvey Direct to Head Throttle Bodies 45mm Diameter 130mm Plenum (butterfly to bell end) 73mm Trumpet (face to bell end) VXR Injectors 440cc Ultra Sonic Cleaned ABF head that as been ported & polished Kent Cams Duration 278 deg Valve Lift 11.04 Full Lift 108 deg Valves Springs 75lbs @ 33mm 198lbs @ 21mm 19.5mm Chrome Silicon Valves (Intake) One Piece 32x6.95x95.5 Under & Back Cut Nitrided Valves (Exhaust) One Piece 27x7x98.2 Under Cut & Polished Nitrided DTA S40 ECU The bottom end is completely standard until the new year, when the bottom end is having cash spent on it. My choice is now to either stay with the ABF block or go for a 9a but I need some opinion on this, reading through this thread and it's not helping me to decide lol. The work I'm looking it have done is Over boring to 84mm giving a 2056cc JE Pistons H-Steel Rods
That is quite a spec of parts there. So are you going to be getting high compression pistons for the bottom end during the winter rebuild? Your car is used for track days and the like, so it will no doubt be getting revved a fair bit. Recent trouble with another forum member's engine, which looks like involving the internal crank trigger wheel, suggests that an external trigger wheel for the management may be a prudent move once cash has been splashed on the engine internals. However this still means you have the option of tall or short block as you could just remove the trigger wheel from the ABF crank, or install a 2.0 non trigger wheel crank from another source, be it 9A 16v short block, or a 2E 8v tall bock. You can find cast cranks in either so as long as you source a forged one then you will be fine. Short block will be lighter by a small amount. EDIT, saw your edit. lol
