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Meet the new boss, same as the old boss...:)


shock96

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Hello everyone. I just wanted to take a minute and give out some info on myself to you all!

My name is Mike and I live in Olympia, WA. I own a 1973 240Z. It is blue with a cream (ugh) interior. This is my 3rd Z. I have been around high performance cars my entire life and have spent quite a bit of time on the track.

My current car is being used as a semi-daily driver. I am busy prepping the car for track events next year. So far I have accumulated the following parts:

Square port 6-2-1 header Jet Hot Coated.

40mm Weber DCOE's w/Cannon manifold and K&N's

P90, E88, N42, N47(for parts) Heads.

Recaro SER seats with brackets

Centerline ConvoPro 15x7.5 and 15x8.5 wheels

R200 Torsen LSD unit 3.91 ratio (Bob Sharp Racing probably)

I will be picking up a 80k mile F54 flat top shortblock here in the next week to work into my temp track engine. I plan on using the N42 head with an Erson cam.

I will be going with a coil over setup using either Tokico or Koni struts and 1 1/8" front and 7/8" rear bars. I will be upgrading all bushings to Energy Suspension urethane.

I am still hunting for a 81-83 ZX 5 speed as well as other parts. I am also thinking about going with a set of 45 or 50mm Webers in the future.

The engine that I will be working on next year will be a 2.9 or 3.0 liter. I am forgoing the 3.1 stroker to get the better revability. I am still undecided on the overbore. I have been working on getting a set of Ross or JE flatop pistons made up that will be either 2mm or 3mm over. I am just not sure. Compression will be in the 10.5:1 range.

The reason that I can run that compression on pump gas will be the use of the P90 Turbo head. It has a superior combustion chamber design, albeit too much volume. I will be shaving the head 2 mm and shimming up the cam towers etc to get the increased compression. I will also be polishing the ports and cleaning up the bowls. Nothing fancy. I plan on using the same Erson grind in this head as well.

I hope to create articles on all these mods as time goes on. I have myself a digital camera now and will take pics as I make the upgrades. I am waiting to get all the parts for the suspension before I get into it. I am hoping to start sometime after the holidays.

So, lets get this forum rockin! The Z is an excellent car for the track. The L series engines are tough as nails and about as sophisticated, but that is ok!

My plan next year is to attend the Proformance driving school at Seattle International Raceway in May. I will then attend their open track sessions as well as the Porsche Club events (I am still a member even though I have sold my 911), and especially the BMW club events as I want to whip my buddies 325IS.

So watch the forum for info and ask questions and I will do my best to answer. I am not the most knowledgeable guy in the world, but I do have some resources that I can call on for answers.

GENTLEMEN, START YOUR ENGINES!!

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3mm overbore ('bout as far as you wanna go without ultrasonically checking the block) gets you to 2949cc, not *quite* 3.0.

As for revability, the main issue is to improve the breathing. It's a myth that shorter stroke

engines rev quicker (under load, anyway, the only condition that matters) than longer stroke engines. There is, of course, a slightly lower redline associated with a stroker, all other things being equal. But this penalty is more than offset by the displacement advantage (peak piston acceleration varies linearly with stroke, but with the SQUARE of rpm). Also consider that the KA24E pistons used with the stroker crank allow the use of longer 240Z rods, which alleviates the redline reduction slightly. And the KA24E pistons are good for 7000rpm in my 240SX, therefore should be good for much more in my shorter stroke 3.1 liter L28. I'm limiting at 7000 anyway.

Why give away X% displacement to gain sqrt(X)% rpm ?

Displacement rules!

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Try to hold your rev limit below 8,000 rpm, The L28 crankshaft has a terrible harmonic, and tries to emulate a wet noodle at high RPM. Even with first class balancing, racing prep, low mass clutch assy. and using the NISMO harmonic balancer (not the euro damper), the crank has a tendancy to break between the no. six journal and the rear main if it consistently goes over eight grand.

Krys Dean

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