420A Bolt-on TechIntake, exhaust, ignition, fuel system, cooling, etc - specific to 2G N/T DSMs. New Members must limit their 420A tech posts to this forum.
my question is quite simple, are the turbo rods stronger? and if so, is the strength difference worth buying forged rods? I'm bulding my NT engine into a turbo engine, going to get forged pistons, wondering if I need the forged rods too, I know I will eventually, but I dont mind tearing apart my engine a year down the line, I should be able to run up to 300 HP on the rods I have I hope? I just want to save any money I can on this project, I am a poor college student after all, he he(I want to be able to drive my car while doing this) so its off to the junkyard for a junkyard engine to rebuild, when it gets warmer anyway, anyway, thanks for the help, and sorry I'm always so long winded about things
p.s. A good block donation to the poor college student fund is always appreciated
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ah, but I have no easy access to stock turbo pistons and rods, the nearest mitsu dealership is like an hour and a half drive, whereas I can just order the forged pistons, and I can order them in the oversize I want too, harder to do with stock pistons, unless you go to the dealership, dont get me wrong, I dont mind spending money for good performance parts, I'm just wondering if I can get away with the stock NT rods for now
I think the answer there is no too - the stock wrist pins are pressed into the stock pistons where the forged pistons have floating wristpins. I don't think you can mix & match without expensive custom machine work. I have a few bent rods as we speak so I'm researching this also.
What was the compression ratio of your stock NT? Seems like Taboo on the OTHER Forum recommends staying with stock NT internals & keeping the boost down a little for guys on a budget. I see FEW good things said about forged pistons for a lot of street use - slapping, different expansion rates, etc.
1G Turbos are 7.5 to 1 & 2G's 8.5 to 1 - I THINK.
Obviously a lot of 1g guys have gone to 2g pistons.
my stock NT compression ratio is 9:1 or maybe 9.1:1, same difference really, and from all I've seen, people run up to 20 lbs of boost on 9:1, though those people have all kinds of fancy electronics, they put out some serious HP, useless for us though, they are racers, not everyday drivers, I'd love to go to 2g pistons, but I dont want that expensive machine work, unless you can go with 2g rods too? do you know? if so that would be great....I would just keep my internals, but I have over 100k miles and need a rebuild, and besides, stock NT pistons are weak from all I hear
wicked93GS,
The rods are exactly the same (I assume you want to build 1G 6-bolt 4G63 with the "big" rods able to support around 450HP). The only difference between NT and Turbo 4G63 shortblocks is in pistons (7.8:1 1G Turbo, 9:1 1G NT) and oil squirters (NT blocks don't have them, but can be easily installed, although not really necessary). If you're on tight budget, swapping the NT 9:1 pistons for new 7.8:1 factory pistons while punching the block 20 over would be the best option. If you're really cheap , you could opt to just hone the cylinders (yourself) without actual boring the block as well (if the cylinder walls are in good shape). The only thing you really have to be careful about is the crank (Try to find find a block with a crank in good shape that doesn't need to be turned -which means no scoring or deep scratches on the main and rod journals - and spins freely without excessive end play). You can micropolish the journals yourself and go with Mitsu or Clevitte77 bearings. Carefully inspect the front case/oil pump assembly as well and replace it as needed (expensive, but much cheaper than consequences of oil pump failure a few months down the road...). Replacing all oil seals is a definite must - and the most important thing: Yank the balance shafts out of the block for good - which will greatly improve the reliability of the engine in the future.. Good luck.
____________________________
Martin
Taboo Speed Shop
............................................................
91 Eclipse GSX
I would prefer slightly higher compression, but I can deal with 7.8:1 I guess, maybe mill the head a bit to bring it closer to 8:1, but if the rods are the same.....turbo pistons here I come, I'll definately get rid of the balance shafts, I used clevite77 bearings(speaking of which I have a set for a small block ford(289 or 302, aka 5.0) laying around if anyone wants them, federal mogul rod bearings too) in my old mustang and loved them, probably use them in this one too, how much do the turbo pistons cost by the way? I dont think I'm going to bother with the oil squirters, just seems like that would rob power, having to move through a mist of oil, the theory behind a windage tray there, speaking of which, does anyone make a windage tray for our cars, anyway, thanks Taboo, you answered my questions
Thankfully Taboo posts here too... BTW here's what I want for Christmas - a modded piston - stock piston ideally - that has machined reliefs in it sufficient to eliminate or minimize piston/valve interference - (kinda like my dinged up pistons right now & 9.9 out of 10 I see on the net) Is length of valve travel so great that's impossible? So what if you lost a little compression turn the boost up - or does it need to be an aftermarket piston with a dome?
- why wouldn't that sell or is it not possible?
wicked93GS,
Pistons cost on average $40 a piece, you might want to call and check with Conicelli: http://partznet.com/mitsudsmclub.html
You might opt to run 2G 8.5:1 pistons, but you'd have to either go with the 7-bolt block or machine the 6-bolt rods to accept the 95 pistons.
Don't shave the head in attempt the compression ratio. You'd decrease valve to piston clearance (and bend the valves the first time you crank the engine) and throw the cam timing completely off.
Not bothering with the oil squirters is a good decision. We built several turbo engines from NT blocks and never experienced any reliability problems (and so did not anybody else after not installing the squirters).
BUCK,
The only solution to your idea would be either relocating the piston pin higher (impossible since the pistons would be slapping like crazy), running shorter rods (= loss of torque) + welding the combustion chambers of the head (to maintain the same compression ratio) or increasing the deck height (very expensive since you'd need a longer t-belt and custom cam sprockets). Notching the pistons would require completely custom units + welding the head as well - and you might as well bend all valves several times for the same money...
____________________________
Martin
Taboo Speed Shop
............................................................
91 Eclipse GSX
thanks for the info Taboo, how much would it cost to machine 1g rods for 2g pistons? that would be the best option, I just dont want to deal with super low compression for the privelege of running a few more pounds of boost
ouch, so much for getting off for less than forged pistons, maybe I could find some forged pistons in the 8.5:1 compression range, anyone know of any, all the ones I see for the 1st gen cars are 9:1
, you could opt to just hone the cylinders (yourself) without actual boring the block as well (if the cylinder walls are in good shape). The only thing you really have to be careful about is the crank (Try to find find a block with a crank in good shape that doesn't need to be turned -which means no scoring or deep scratches on the main and rod journals - and spins freely without excessive end play). You can micropolish the journals yourself and go with Mitsu or Clevitte77 bearings. Carefully inspect the front case/oil pump assembly as well and replace it as needed (expensive, but much cheaper than consequences of oil pump failure a few months down the road...). Replacing all oil seals is a definite must - and the most important thing: Yank the balance shafts out of the block for good - which will greatly improve the reliability of the engine in the future.. Good luck. 
