BayAreaZT Posted August 26, 2006 Share Posted August 26, 2006 Just picked up a new set of Arias forged pistons because I got a smokin' deal on them. P/N is 320980. This is supposed to be for a L-31et so the bore is 89mm. Has anyone ever used these pistons in their turbo motor? I'm not sure if I should use them for my built motor or try and sell them and get pistons for a smaller bore. I'm a little wary of boring the block to 89mm. Quote Link to comment Share on other sites More sharing options...
240hoke Posted August 27, 2006 Share Posted August 27, 2006 I think a good many people have gone to 89mm, prolly jsut wanna get the block checked over for cracks when your done. My friend went to 3.2 L on his L motor and ended up cracking the cylinder wall after startup. They determined it was a casting defect that made the wall a little thinner in that spot, and sorced another block.... so far so good. Arias pistons are good shi_t, espeically if they are zero silicon ones. A friend of mine is a distributor and runs Forged internals, he is having very good success with them in his 350z builds. -Austin Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted August 27, 2006 Share Posted August 27, 2006 I am running Arias pistons in my 3.0 stroker and I am very happy with them. I have also had very good customer service with Arias. If you are concerned about boring the block that much take it to a compitent machine shop and have it sonic tested also have them magnaflux the block, if those test are good you can have the block bored with no worries. Dragonfly Quote Link to comment Share on other sites More sharing options...
BayAreaZT Posted August 27, 2006 Author Share Posted August 27, 2006 I wonder what rods these pistons were designed for. Pin height is 27.8mm. I guess I could try and get custom 138.5mm rods with the LD28 crank or use the stock crank with custom rods and mill the block. Seems like if I go with these pistons I'll fall into the while I'm at it trap. Anyone know who makes L-series rods longer than the 240Z rods? Quote Link to comment Share on other sites More sharing options...
jeffp Posted August 28, 2006 Share Posted August 28, 2006 I realize you got a good deal on the pistons. BUT, why are you interested in the 3.1 liter engine/bottom end for a turbo application/ First thing, the difference between a 30. liter and 3.1 liter engine, run normally aspirated, is a difference of about 2hp. Second, the boost and power will be determined by the turbo. So WOT will not really be affected or improved by the 3.1 liter swept volume of the cylinder. Most importantly, you are going to be running the cylinders to thin for a F54 block. You want an N42 block with offset boring to get the cylinder thickness uniform, and to match up the conbustion chambers perfectly. I don't recommend a 3.1 liter for turbo applications because of the cylinders, you can add stroke and get there, but there again, you will have to pay alot of money, and modify your block to get the crank to turn in the block without clearance issues. Use the 89mm pistons N/A and be on the safe side. You want a good cylinder wall for the turbo application, so I figure why push it with the results you will net. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted August 28, 2006 Share Posted August 28, 2006 What Jeff said makes a lot of sense to me. Dave Quote Link to comment Share on other sites More sharing options...
jgkurz Posted August 28, 2006 Share Posted August 28, 2006 Most importantly, you are going to be running the cylinders to thin for a F54 block. You want an N42 block with offset boring to get the cylinder thickness uniform, and to match up the conbustion chambers perfectly. Jeff, can you elaborate on your above statement? My understanding is that the N42 and F54 blocks are the same except for the siamesed cylinder walls in the F54 blocks. Is the offset boring something that's done custom on a build up or are you saying this was done at the factory? In theory, wouldn't the N42 block have weaker cylinder walls? I don't recommend a 3.1 liter for turbo applications because of the cylinders' date=' you can add stroke and get there, but there again, you will have to pay alot of money, and modify your block to get the crank to turn in the block without clearance issues. Use the 89mm pistons N/A and be on the safe side. You want a good cylinder wall for the turbo application, so I figure why push it with the results you will net. [/quote'] I agree with discouraging a 3.1 liter on a turbo build. I went 3.0L on my setup because I wanted to ensure thick cylinder walls. The advantages of keeping a rigid cylinder wall far out way an extra 100cc's. To further make the point, I've seen several 2.8L turbo L28's that make huge power (more than me..) without spending the $$$ on a stroker. If a person had to chose one or the other, I'd HIGHLY recommend buying on a decent BB Garrett turbo, external wastegate, madrel exhaust and intercooler before going stroker. Just my .02C Quote Link to comment Share on other sites More sharing options...
BayAreaZT Posted August 28, 2006 Author Share Posted August 28, 2006 John - from what I have read in the past, the N42 block is completely siamesed between the bores. No cutout for water passages so there is more material between cylinders. Offset boring is done to ensure even cylinder wall thickness for all cylinders. I agree with all the arguments against the 3.1 turbo build. I really had no plans to do this build. I just wanted to see if anyone has done this successfully in the past since I do have the pistons. I think it can be done but it's just too much time, money, and effort than I want. Quote Link to comment Share on other sites More sharing options...
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