Like Brookster said is the abf inlet and kr exhaust a better combo that abf in and out...also am I better going for 268 in and abf out or 268 in and kr out lol
I've tried to put ex. KR cam to inlet on my ABF but the car runs slower.Than i put 2 ex. cams from ABF and it goes very well.It is better than before the car rev quicker and have better top end.Before pulls hard to 6000 now pulls to 6500.The car is mk3 abf
2 ex ABF cams are basically the same as running a set of ABF cam intake and exhaust. Just watch the specs at the beginning of this thread.
I've tried abf ex and kr ex(to inlet) and the car was slower than before.I think 2 abf ex cams is the best combination.
Hi. interesting thread. And furthermore of ABF cams does some one know any specific difference in ports of an 9a head and ABF head. I have a full ABF but had to change head and the only available from then was a 9A head. I still have mounted the ABF cams but hard to know any change. motor feels better but because I change internals for better CR. also have some question about this because I bought a forged set for CR 11.1:1 and 83mm bore and as I shaved the head about .010" I'm guessing that CR should be about 11.5:1 but not :sure according to this formula that I found on the internet http://www.csgnetwork.com/compcalc.html where according to the ABF specs and new bored set of pistons Bore=83mm Stroke=92.8mm head gasket bore diameter=82.5mm compressed head gasket thickness=1.5mm (most of the metallic sandwich gasket) combustion chamber volume=44cc (I found most of the chamber volume for 9a and KR where from 44 to 46 cc I assuming is 44cc because of the shaving work) deck clearance=.254mm (typical deck clearance for ABF block according to a vwvortex guy) pistons have a little bit of dome but only on the center about 80mm and 1mm height here are some pictures that shows lft side original ABF piston right side forged piston with little bit of dome And after all the question comes to mi mind. because I want to stay as closer to 12.0:1 CR as it could I plan to use an AFN crack or new beetle TDI crank to rise stroke to 95.5 instead of 92.8 from the ABF crank according to the formula I will only get a CR of 10.67:1 is this true or I have mistake in data?
Hello and welcome. First off you won't want to run 12:1 cr with std cams...ABF or KR...unless you plan on replacing them quickly again. You've got sort of the right idea but some of your figures are wrong. If your using a standard multi layer steel ABF type head gasket they are 83.5mm bore with a compressed thickness of 66 thou. The chamber size you require will be dependent on the intruder volume of the piston and final position of the piston within the bore...i.e the deck height. What sort of spec is the rest of the engine...i.e...camshaft and cam timing range to be used? Also...the longer crank you plan on using will raise the pistons in the bore and may need corrective machining to get clearance and c.r right.
thank you very much mr hillcimber. I'm using the standar forged cracnk shaft but plan I had sharpened and balanced but plan to use a AFN of beetle crank for the 95.5 stroke they also are forged. I'm using an autotech's variable timing cam pulley that I forwarded 3 degrees and also didn't mention that I have Methanol-water system. With 92 octane fuel and meth is approx. 130 octanes fuel. So correcting the data that you kindly mention. I will still have a CR of 11.54:1 according to the formula. is that right? and Why is that I can't use the standard ABF cams with CR of 12:1? temperature? meth-wather really cools down. by now I can't even get to 85 C and maximum oil temp was 105 C sill plan to use and oil cooler radiator. what I notice more rising the CR is torque. but also fuel economy actually is 9.2 L. every 100 Km. I have a performance chip installed. but I assume that economy that I have is because of the Meth Thankyou
also forgot to mention that I have a .04" clearance on the piston rings they was intentional set with this clearance in order to have less worn on them and skirts and also have the possibility to maybe use nitro some time. Actually is consuming a little it of oil but I think that is because of this clearance
That puts a different slant on it. Generaly std cams need a lower compression to avoid detonation...a 12:1 c.r is the ball park for sub 290-300 degree cams....your current octane with however be a big help. Looking at your pistons, the intruder looks to be around 5-6cc...do you have a spec for them...what make are they?..and how far down from the block deck is the squish/quench zone...the flat section around the valve pockets/cut-outs.
Adding to what Jason said. Running std ABF 254 deg cams (218deg at 1mm) with high static compression 12:1 +, by the nature the stock items tend to have minimum overlap for the smoothest customer idle, will cause high dynamic compression or cylinder pressures that easily hit the det limit during a combustion event. Custom mapping will reduce the chances of a detonation event, but you would probably have hardware with such a low det limit that you will make less power and torque than a stock motor, even with good quality RON fuel. Such an engine will struggle correctly to run on regular 'pump fuel' due to the great potential for knock at part to higher engine loads. Running a 'chip' in the production ECU is probably a poor means of controlling such a beast also due the the custom fuel control and ignition timing required. That is my 2 bhp the controls perspective, I will leave the rest to the engine professionals
