Twin Turbo LSX Datsun 280Z
04-25-2015, 09:17 AM
#841
4.8 crank! 
Would stand up to more abuse for sure. I'll admit I've yet to see a big bore 4.8 crank combo that put out impressive numbers without exotic top end parts. Can't imagine 5 more psi wouldn't make up for the loss in stroke across the board though. Seems if the goal was to push the OEM crank/block as far as possible, the 4.8 crank would be the way to go. Not practical for you though I know. You'd have to change alot of your other parts to make it work.
Would stand up to more abuse for sure. I'll admit I've yet to see a big bore 4.8 crank combo that put out impressive numbers without exotic top end parts. Can't imagine 5 more psi wouldn't make up for the loss in stroke across the board though. Seems if the goal was to push the OEM crank/block as far as possible, the 4.8 crank would be the way to go. Not practical for you though I know. You'd have to change alot of your other parts to make it work.
Also any idea what kind of forces are applied to the rotating assembly vs stock stroke vs 408 etc.?
Last edited by oscs; 04-25-2015 at 09:26 AM.
04-25-2015, 11:41 AM
#844
On a side note I noticed some discoloration in my exhuast ports. Take in mind this motor has around 3k on it. Do these lighter areas look like hot spots or just lack of soot build up? There are two on this bank and 1 on the other. Anything to be concerned or look into? All the plugs looked perfect.
04-27-2015, 04:08 PM
#853
Crankshaft is straight as an arrow. It actually has less than .0003 run out. The journals looked fine and just needed a slight amount of polishing. Ill pick it up tommorow and start reassembling the motor this week. The OD and Glide should be arriving late this week/early next week.
04-27-2015, 04:26 PM
#854
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The shorty powerglide/ GV setup sounds pretty cool. I never gave much thought to putting a GV behind the transmission in such a small car, just figured it wouldn't fit(never heard of a "shorty powerglide" until this thread).
04-28-2015, 06:49 AM
#859
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what a great shot. I would avoid 8500 like the plague and focus on maximizing the torq from 3k to 7500
anyone know where I can get short stroke forged crank? I'm looking to do a short stroke 4.8 build and boost it hard on e85
but honestly I'd leave 8500 for the pro comps at the digs
it's really hard on valve springs and the rods. if you really want to go that high you'll need good heads in addition to the turbos that will stay in the meat of the map at that flow rpm level
It would be cool to scream it that high. the comp guys used to turn down the crank and run a small big end bearing to lighten up the rod and reduce the friction. I'm looking into a setup to do just that!!
love your datsun, I miss my 468 BB datsun but alas I was young and foolish and grenaded much on that car and twisted up the frame a bit
time to build another one!
my recepie this time will be the "little engine that could" with a 480LE and a shortie stroke 4.8 that I can get into the power band quickly and rev the snot out of it. for me that means 7500
anyone know where I can get short stroke forged crank? I'm looking to do a short stroke 4.8 build and boost it hard on e85
but honestly I'd leave 8500 for the pro comps at the digs
it's really hard on valve springs and the rods. if you really want to go that high you'll need good heads in addition to the turbos that will stay in the meat of the map at that flow rpm level
It would be cool to scream it that high. the comp guys used to turn down the crank and run a small big end bearing to lighten up the rod and reduce the friction. I'm looking into a setup to do just that!!
love your datsun, I miss my 468 BB datsun but alas I was young and foolish and grenaded much on that car and twisted up the frame a bit
time to build another one!
my recepie this time will be the "little engine that could" with a 480LE and a shortie stroke 4.8 that I can get into the power band quickly and rev the snot out of it. for me that means 7500
04-30-2015, 08:49 PM
#860
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Did you happen to hear from anyone how much power you could actually put through overdrive on a well built 4L80E? I had a new one built last winter for my Z and just received 5 boxes of Holley EFI stuff including the 4L80 trans harness, so I've sort of commited to running it. I assume the Dominator could be programmed to back the boost off in overdrive.