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What Can I Do With The Z31 Engine?


Z31Guy
10-06-2009, 09:05 PM
Hey Guys and Galls!
I am driving an 87' 300zx Turbo (W-series) and Just thought that there are a few people like myself that are not sure how exactly to make the most of it.

Well, I have done my share of work on this old P.O.S. and now it is starting to come together. I just got it on the road and am kicking some tail (probably because it looks like a bondo add, and the only people that wanna race cant even tell what it is!) but, now I am to the point that if I want more power it has to come from inside the engine.

Call it strange, but i wanna keep this engine, not B#stardize it (hybrid) with other engines' parts, or swap it for a "better" engine.

So, there is the obvious:
*New Intake Manifold ($$$)
Pathy is not the best! Honestly a cored out stock manifold will get you almost as much flow as a high dollar race manifold (excluding custom builds)
*Port & Polish ($200-$300)
hard to mess up, find a shop, have it done...
*Valve Upgrade ($$$)
new valves are a good gain, the different shape and thickness of the shafts are a generally overlooked way to increase flow. Ferea is the ABSOLUTE best! Some have said they have seen a 2% hp gain frome just this upgrade.
*Cam Upgrade ($180-$1000)
Re-ground vs. new, New is better/stronger/more reliable, Re-ground are cheaper, and you can have them any way you want... BUT you HAVE to have them messured after you get them back! They can get messed up when they are being re-ground and cause 1 or more valves to have a different lift... A good shop should do a good job, but you should bouble check just to be sure if you are sending them off.

Now everyone knows, but everyone i know still has questions...

what is the best Cam lift/spacing/overlap/duration of a performance cam for a Z31?

if you bore/stroke how much can you do? 20 over or is 30 over safe for high HP?

if you do bore/stroke it, what displacement can you achive? 3.5L.. 4L? and is it worth it to do one over the other, or both?

what pistons should you use if you do bore/stroke?

what turbos are good in combinaton with the Z31 without needing NOS just to spool the darn thing?

where in the EFING heck can you actually find larger injectors?

Thanks for listening~
This and more to come!

Z31Guy
10-22-2009, 12:19 AM
Paeco... yeah, all that needs to be said if you got the money!

They will do any cam grind for $260, there is a $250 core charge, but if you can't pay, and you cant have your car out of business for long enough to send them in, you can call in your order and they will give you two weeks from date of recipt of new cams to mail in your old ones!!!

Pretty slick!

Also, if you are in the maket for just about any Head/block work, they have the means, course this would involve sending in what you needed the work done on... not an option for those who's Z is a daily driver.

But, as for Stroker kits, they do them all custom to your specs, and the needs demanded buy your desired apps of the car. their standard Stroker for the Z31 goes hand in hand with a .2" overbore and will send you safely to an awesome 3.6L!!! 20% extra displacement for $1999!!!!

FYI the stock size is 87mm and you can get over 97mm bore if you have the block sleeved, that is some power there bro!

As far as head work, $1000 gets you SOOOO much! just check out the site... Paeco.com

I am sending my entire engine out to them in a few months to get all the work done i can. I cant wait to see the gains i should have when that B-otch comes back home! I am installing a Spec stage 3 clutch and 12lb. flywheel ($713 total... not bad!) with my new Walbro 255 FP and 420cc injectors (off an old Benz) as well as a MSq-II EMS/ECU

Been doing some research and found that the MSq-II basically does the work of fine tuning your performance rod for you! You will how ever need to put all together (if you wanna save $200+) in conjunction with a wideband O2 setup and for the sake of ease a boost controle unit all controled by the MegaSquirt-II.

The boost app can be purchased along with the MSq-II system for about $40-50 as i recall, but the O2 is going to hit you for a bit bout $300-ish if you dont already have a sensor and guage (you dont need a guage, you can do all the monitoring from the MSq-II system) bout $190 for the connecter cable if you just want to connect yours to the system.

Cant wait to get all this stuff bolted up! :)

Thanks for playing,
Z31Guy

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