We know that you can run a 150mm rod in a 220mm block with the 86.4 crank. But can you run a 155mm rod in a 220mm block, or would that result in too short a piston height?
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Piston can be done with compression height aprox 28mm so, rod lenght will be next 220-28-43,20=148.80mm With crank 86.40mm.
If you will find 2.0 20v 5cyl NM engine if remember right with Compression height aprox 28mm pistons,rod lenght will be next 220-28-39.75=152.25mm with crank 79.50mm.Audi S4 2.6 20V STROKER kkk26/27Comment
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It all depends how far up your piston manufacturer is prepared to move up the wrist pin. My engine runs 150mm rods and the wrist pin is just below the oil scraper ring at that. I think you could push a little more out of it but probably not 5mm.Comment
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Yeah ok, I was thinking 150mm was just about as far as you can go. Just good to get other peoples experiences. 155mm rods are an 'off the shelf option'. Will just have to go 150mm custom rod. Should rev fine without compromising reliability with a bit extra capacity.Comment
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What about this combo, vw tall block, 86.4 crank, 155 rods.Comment
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I'm using a stroker crank 95.5mm and 159mm rods. Why bother with a stock crank in a tall block. The extra cc is more worth while as our heads don't flow well enough for over 8k rpm power.
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Forgive my ignorance but I am just trying to explore possibilities. 10-12 years ago tall block 95.5 crank 159mm rod 20v head combos were pushing the boundaries. Now they are accepted as a good combo, good torque and well within the heads flow capabilities in terms of rpm ceiling. I know short block/86.4crank/150mm rod are a good combo.
A tall block with 86.4crank/155mm rods will have a nice rod ratio for revs. Ok we hit the flow restrictions of the head. Will a good port/polish/oversize valve/mechanical lifter job address this? Now we also hit the oil pump safety threshold. Will a dry sump system address this? I just want to see what the boundaries are before I commit to my exact setup?
Ultimately I want a setup that makes at least 650hp atw on E85 with the smallest turbo possible but with rock solid reliability (is that all!).Comment
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Seems like a costly way to explore possibilites. Plenty of setups have hit 650 awhp on a 2.2L, although with larger turbos that would sacrifice response down low in the rev range.
E85/meth injection/2.5L stroker/built head/EFR 7163 will get you very close to that figure and not sacrifice spool below 3k rpm, and pull hard to 8500 rpm all day. If not, then the EFR 8374 should get you past that figure and still maintain reasonable spool if spec'd with an integrated quick spool valve.2013 Touareg TDI /// #farmenwagen
1992 80q 20v /// Eventual AAN'd Winter Sled
1990 Cq /// Project: Because RacecarComment
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Yeah, everything keeps pointing to tall block stroker. I just like the rod ratio in the short block with 86.4 crank/150mm rod. Need to choose between the two!Comment
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I think you can get carried away thinking about rod ratios. Some Hondas have crap rod ratio and rev hard without issues.
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Thats right Des. It seems rod ratios are a hot topic these days. Lots of heated support on both sides.Comment
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Yeah Hondas do rev hard when they come on to the second cam. But I would never own one. They always seem to put the smallest motor they can get away with in their cars and no torque!Comment
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In my opinion best combo for linear power delivery is 92.8 sroke with 144mm rod. Revs high (how high a motor revs is determined by cams, rod ratio determines piston speed , rod angle, tdc dwell, stress on crank and block..etc), smooth power delivery all the way to 8500+,Comment
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I would love a 92.8 crank but they are hard to come by. Do Eurospec still supply? I want the OE forged one, not the billet aftermarket.Comment
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