Trust me, if you're breaking an 82.5mm block, being revved hard on a daily used vehicle, there is something totally not right. You can't suggest that you're stressing an engine harder than a works built engine, sorry.
Chris i didn't say that im stressing the engine harder than a works one but that it is stressed every day..Anw i checked everything and there were no problems anywhere..I'm running the same setup now with another block and i don't have problems.
I think we're slightly across purposes & perhaps this is one for a separate thread, ie boring to 84mm (or not).
Interesting, so, if in the first 45 degrees of crank movement the piston has moved further with a shorter rod, in the second 45 degrees of movement, the oppsite would be true and the longer rod will have travelled further in the same period of time. Now, this will have different effects on the power and intake strokes. On the intake stroke you would want the piston to have maximum velocity at the same time as peak valve lift for optimum cylinder filling, i.e later in the crank rotation cycle than 45 degrees. As for the power stroke, i'm not entirely sure what the additional dwell time around tdc will do, other than that the flame front will have more time to develop and higher cylinder pressures will result from this. Impact on power and torque in the real world, well, your guess is as good as mine!
More: Code: [B]Engine Bore Stroke Rod length Compress Deck height* Comp height BHP NM Characteristics[/B] 9A 82.5 92.8 144mm 10.8:1 220mm 302mm 134 186 More power ABF 82.5 92.8 159mm 10.5:1 236mm ???mm 150 180 More torque Type-R 87 84.4 153mm 11.7:1 223.9mm ???mm 246 217 No torque! * Crank centre line to deck
Chris we can't say there is no torque just because the Honda don't have lot of stroke, no of course they have got a lot of torque, thats why you can see a 197hp from a Honda Type R, Horse Power is just a function of torque: HP= Torque x RPM/5252, ABF= 180NM x 4400/5252 = 150 HP, They gave the Honda a better racer's motor specs
Well indeed! "No torque" was quoted earlier in the thread, hence "!" being left in. But which Type R engine are we dealing with? 197 or 250?
hmm. Not really an accurate comparison, as each block has a different head, management and cam profile on it. Fit the best possible parts and mods to each block for a more accurate comparison. And maybe some dyno charts too, peak figures are just that - peak.
Have a look at the thread title The 9A and ABF heads are rather similar (& swappable, so irrelevant). Of course it takes no account of Honda heads or mgt. It's a bottom end comparison, and the point about the Honda's characteristics is being eyeballed, in addition to the difference in power/torque behaviour of the 9A vs ABF (see daved's thought-provoking diagram above).
True. But, it takes another 135 deg to catch up at BDC. It's the acceleration which is changing. I was only looking at why VAG might produce, what are, in effect, two identical motors, except for the rod length. (Valves, cams, injection, could all be the same if they wanted to do so). The longer rods, and, I guess, the pistons would just be heavier? I am now wondering if Diesels are all long rod motors? Sorry folks there are errors in my sketch, I lost 5mm somewhere. Corrected figures at 45 deg are: 159 rod = 16 mm travel and 144 rod = 17.4 mm travel: diff = 1.4 mm (Same difference between travel lengths, just larger quantities) At 90 deg, 159 = 53.3 mm and 144 = 54.1 mm - still further, but closer: diff = 0.8 mm At 135 deg, 159 = 82.6 mm and 144 = 83 mm - still further, but closer: diff = 0.4 mm At 180 deg, 159 = 144 = 92.8 The problem is, that, as the 144 has travelled further, the volume above the piston is greater. So, the force on the piston at that specific time, 45 deg, is lower in the 144 engine. By: P1 x V1 = P2 x V2 and if F1 = Force at detonation, then: Force at 45 deg: 159.F2 = 0.158 x F1 and 144.F2 = 0.147 x F1 But, if you consider the average force exerted during the travel to 45 deg, then: 159.Fav = (1 + 0.158)/2 x F1 159.Fav = 0.579 x F1 144.Fav = (1 + 0.147)/2 x F1 144.Fav = 0.573 x F1 Giving: P.159 = 0.579 x 16 P.159 = 9.3 units P.144 = 0.573 x 17.4 P.144 = 10 units ie: About 7% more. I have done very rough calcs., of a similar nature, to prove that the average torque is higher in the 159 rod motor.
I'm not sure that's right. I have 1.9 diesels down as 236mm tallblocks with 172mm rod length and 26mm gudgeon pin. Certain my 1Z 1.9 TDI motor is a tallblock.
VAG did build an oversquare 2.0 L four cylinder engine: 86.5 Bore x 84.4 Stroke - 144 Rods - 8 valve only. Almost a Honda (87 x 84.4 - 153) with shorter rods! A better engine then? Just needs a 16v head! Would a 4.2 L Audi V8 head fit? 84.5 bore. Oettinger made a 2.3 L 8v version, with bigger valves, but not been able to ascertain if they built a 16v head! http://www.clubgti.com/forum/showthread.php?t=199689&highlight=924 Just been looking at ETCC racing 2.0 L engines in the day. Alfa & Fiat: 84 bore x 89 stroke = approx 250 bhp Ford: 90 bore x 77.6 stroke = approx 280 bhp BMW: 89.2 bore x 80 stroke = approx 290 bhp No rod lengths though.
The IDI turbo (AAZ) and TDI (1Z & AHU) engines have 144mm long rods with a 26mm gudgeon pin. The IDI na (1Y) engine has 150mm long rods with a 24mm gudgeon pin. The diesel pistons are a lot heavier around the crown so the pin is lower in the piston. This is why they still reach the top of a tall block. It is a waste of time determining which engine (9A or ABF) makes the most power or torque based on factory figures as Skyrocketeer states, as they use different heads, cams and management. If you build the two engines with identical parts and management then measure the figures, that would be far more accurate but as a 9A does not have an internal crank sensor you cannot run it on ABF electronic management. K jet on an ABF is however possible but you would need to fit the entire 9A head with its lame inlet cam to compare like for like. Even then the ignition may well be mapped differently and negate any true comparison. Fitting an suitable final drive to optimise the gear ratios and lsd which suits what the car will be used for will make more of a difference than the power or torque differences between the 9A and ABF engines once tuned. Transmission should be the first thing you address with regard to a competition car. My old 1.6 8v with 125bhp could get buy a 150bhp Civic with Mugen bits on it as it's gearing was optimised for the circuit we were on.
Hmm, well that sounds pretty convincing. So what's going on with the 1Y? It's not an entire waste of time - I appreciate I've put quoted figs in that table and if they were all on identical standalone, it would be a far better comparison. The main thing was to put down the bottom end dimensions, so they could be see next to Dave's 45 degree discussion. Keep up. I've asked what circuits are being used earlier
It is as convincing as it is true. Confucius say: "Trust a man that has hands as dirty as Daved, for he must have stripped many a Vag diesel engine" The 1Y na engine uses smaller gudgeon pin as it does not see as much force acting on it as the turbo engine. This means the piston is slightly different in design and allows the pin to be nearer the crown hence the longer rod. Get with the diesel program man!
Thanks, makes sense. I am with the diesel program btw. Today not only did I vacuum the diesel, but I Vaxed the seats. After using it effectively as van for 3.5 years, I thought it was about time
