turborocket

I have been a Z32 guy and now getting into first generation Zs so I have some questions.

I am on the trail of a '75 280z. It will be a street-legal, track-safety-prepped car for me to do DEs and Solos for the next year or so. I want to build a beefier motor. What kind of power can I squeeze from a L28, and what are some of the recipes to get there. I'd like to get 300 hp but would go higher if possible. I will be doing this over the winter this year, and because I will spread this over several months, my budget for the engine build is pretty good, I'd say around $3500 - 4000. I will be doing most of the assembly but will farm out the machine work. Tell me what I should be considering. Along with the cost and time elements, these are my other parameters:

- as already stated, would like to stay with L28 (but open)
- no turbo-charging, no super-charging
- stroker OK, if reliable
- no V8 conversions
- I don't care about classing this yet, but eventually I might take it off the street and use as a GT car.

Thanks for the help.

----
Peace...

TurboRocket

z17

Dude your picking one of the best categories to do to your engine, because you don’t want turbo charging nor do you want super charging with no engine swaps from L28's to v8's. Going naturally aspirated is one of the best things that engines like, becuase it runs freely on its own and it screams on its own, not like when an engine is force inducted and all the strain is being put to the crankshaft and all other parts. Don’t get me wrong that yes you can get a hell of a lot of power going turbo/super charged. Im not a certified mechanic but I can tell you what things you might want to consider in researching. For example, you wanna make the engine as less of a restricted engine as it is already, meaning get a good freeflowing exhaust with headers and a 50-state legal freeflowing catalytic converter. Also if you wanna make the most power out of a naturally aspirated engine your gonna have to get rid of your intake manifold and throw on some nice individual throttle bodies, from there you have a choice of going carburated for more bang or your other choice which is going fuel injected where you can still adjust your performance via a good programmed ECU which is the brain of the engine, that conducts how much fuel flows through those injectors and the ignition timing. Now your head will need some good port and polishing and a good valve job done. Also if you want more torque and power get you a stoker kit that includes new lightweight long piston rods, a lightweight crankshaft and pistons of a high compression. When you’re going N/A on an engine and you want a lot of power you’re going to want to up the compression so that it runs faster and better. Your camshafts will also have to be replaced for high rpm usage based on that you want to go Grand Touring on that car. One more thing I forgot to mention be sure to get you a nice flowing fuel pump so that your engine never starves to death and leans out in gas causing loss of horse power and cracked or burnt piston rings or pistons. Just remember man on a fast reliable natural aspirated engine it best to go all lightweights with all the parts as possible, from your engine fan all the way to your transaxle, everything should be lightweight so that your engine has a higher hp output. If you can get your car to that spec for sure you can hit an easy 300+ or more on the horsepower if you get some one or you to do it right. Like I said im just passing on some knowledge from me to you and I will also recommend that you research on who can do this and what you need to make that engine fly. I have been doing engine work on all types of imports, and like you have only some available funds. But I help out friends who have the funds to do this so that how I know.

Bracem

na car is hard to make over 250 rwhp. probably count on 225.
This will cost a lot and you have to max it out.

turbo with stock injectors boost up intercooler (saab) sds and msd 60mm throttlebody and I am hoping for 240 rwhp
With bigger injectors and 15 pounds of boost you should hit 300 rwhp without too much trouble need a bigger clutch and exhaust pipe.

If you are building the car why not buy a junked 280T car and swap the stuff over - it bolts in. That is what I am doing and the car is 400 pounds lighter than the 70-78 cars.

I am putting on ps too mustang rack with datsu turbo motor pump.

I retrospect i wanted everything to be Datsun and will be happy with a realiable computerized car with 240 rwhp and if i want more i can by the inj for $500 US.

However if you want POWER then buy a swap kit for the v8 and put in a Chevvy crate motor.

Cheers Mark

turborocket

Z17 - thanks for the info.

Bracem - the two ideas you suggested are two exact ideas I don't want to do.

Still looking for definitive "recipes" if anyone has them. From some of the reading I am doing here and elsewhere, looks like I should go with a diesel crank, 240 rods, an probably a Rebello or Sunbelt head. What cam should I run? what pistons? EFI or carb?

AlansZ

It is very hard to get the sort of power numbers you are looking for out of your engine, it will cost alot of money, a lot more than you budgeted for. You also specified that you wanted it to be road drivable as well, but you will find with the cam required to get as much power as you want and the large amounts of compression etc, it will be very hard to drive on the streets. That's not to say L28's can't be quick, just look at norm's car, he runs 12 sec quater miles with the SU's. I think the L31 conversion will be the way to go for you, but keep in mind it is quite exspensive. I would have to agree with bracem, if you want that sort of power you will have to go turbo or V8. Just mho

Alan, Australia

AlansZ

by the way I also agree with what z17 is saying, he has it dead on, but the money required will be alot more than you have budgeted

Alan, Australia

L0ki

Ok here is my idea on the show. I agree wholey with z17 lighter is better.

So bearing that in mind get a 240Z instead of a 280Z ... lighter chasis to start with.

Next strip everything out of the interior. Take out all carpet sound deadening, console, standard seats, plastic pannels and paint the interior.

Get lightweight race seats.

Get front and rear strut braces (they make a big difference and you;'ll need somewhere to put ur straps onto)

Get an L28 get the desiel crank (2.9L keep mind this will make the motor a longer stroke and rev slower) and then bore it out to 3.1L.

Get tripple DOCE 45mm webbers

Get the N45 head the 280ZX one with square exhaust ports or the P90 with pnumatic rockers. Get a full port and pollish and plane the head back a couple of mill this will depend on teh pistons you use too. (im not 100% sure on the head types and numbers but i know u want the Nxx or the P90)

Thin metal head gasket and a "race" cam.

240K rods, maybe forged pistons.

Run electric fans instead of clutch engine fan

Run a good set of extractors and free flowing exhaust at least 2.5" and because its a 240Z you wont have to run a cat (well in australia you dont) and run a good quality race muffler.

3 or 4 core radiator alluminium if you can afford it for weight. Take out the heater and run a pipe to the back of the radiator for hot air.

Get one of the closer ratio 5 spd trannys, i dont know what you get them out of in the US but in australia early '80s L24 skylines had close ratio boxes.

Run at least a 4.11 R180 LSD (R180's are lighter than 200s)

Get vented, slotted high performance front rotors and competition brake pads.

Get fibreglass front guards, hatch and bonnet.

Get light 3 piece wheels 15" - 16" and run race tyres (cut slicks are street legal in australia).

Hrrmmm that should give you a start

240z

I would like to add the following.
N36 intake manifold from a L26 engine. N42 Head, F54 Block. This should bring comp ratio 10:1 roughly. SM performance needles from british SU's for your Hitachi SU's. Provides more fuel. Change the distributor to a electronic one. Remove ballast resistor, I'm talking 240z's here. Get a high performance coil. A Mild Cam, some head work porting polishing. Lighten everything and balance everything. A 3.9 rear end at least and 5spd gearbox from a 280zx.
Should see a start towards your goal with these mods.


Gavin,
Melbourne
Australia
73' Datsun 240z

240z

If your interested have a good read of this site here.
http://www.geocities.com/MotorCity/2824/engine.html
excellent site this guy knows his stuff.
Enjoy

Gavin,
Melbourne
Australia
73' Datsun 240z

TURBO260

Sorry to say,but no matter how much you spend on your NA motor, a stock turbo motor (long block) can out perform it for a fraction of the money. The benifit to boost is that your motor DOESN'T have to work so hard when your not in boost, that makes turbos much more streetable than NA motors. I've yet to see anything less than a full blown race motor approach the numbers you want. I have a friend who autocrosses a 240. It is purpose built, stroked, 12= to 1 compression, under 2100 lbs, and my stock engine turbo 260 smokes him by over a second in the 1/4 mile. His car can only run on race gas, mine just drove to San Antonio and back (about 2000 miles) getting 25+ mpg! I'm not saying that NA engines are bad, but don't expect to get more than 250hp out of a well tuned, and extremely well built engine. I would just reconsider a turbo.
Jim

turborocket

Thanks everyone! Some very usable info here with which to start.

I had been looking for a 240 but I found this 280 in great condition for a great price, so I will play with this for a while. Maybe later, I will build an all-out 240.

I already have a Z32 TT so that is my turbo car. I just want to stick with an NA for now on an early Z. I am less concerned about getting to 300hp - I said that in my original post, maybe just thinking out loud. I know I can achieve this kind of power easier going with a turbo, but again, just want to stick with NA for now.

By the way, how much weight difference between the 280 and the early, early 240s? Are the early 240s still relatively easy to find in usable condition?

AllmyZs

I a building an 78 L28 for my Z this winter on paper it comes to just over 270HP. That is where I want ti so i dont break traction in a corner and wreck the thing. It is gonna cost about 3000. for parts and machining and beer.

Gotta get my Z's

nzz

see my post of today. I've had some email chats with norm and he's pretty friendly and keen to pass on info. His email address used to be in his profile...do a search for 12 second su or something like that to find it. I think he did a 12.9 which must give him somewhere between 275 and 300hp. That's about right for a well tuned balanced l28 with one extremely lumpy cam and some big valves. When you do the head make sure you get the bigger valves put in. anyway good luck....I'll be doing the same soon too :-)

tyco1983

Alanz-
To get around 270hp out of a z motor and have it run for more than a couple months, you're going to spend quite a bit more than $3000. Hell, I almost spent that much at Sunbelt Performance Engines on the headwork alone! Not to mention that the lower half cost me about $3000 too after all the balancing, polishing, shotpeening, and blueprinting. Nzz-Norm's a great guy, but his z is NOT producing 275-300hp. I've talked with him on the phone many times before about his set up. Some people completely ignore some of the most obvious and inexpensive says to gain time on the strip-he doesn't- He uses precise tuning, SMALL rear tires, and a 3.9 rear giving him REAL deep gears on nice and sticky tires, and he's practiced 100's of times. That's why he's been in the 12's with his z. My z is pushing 200 rwhp b/c of all the nice/expensive work i had done to it, and I see 13's at the drag strip with a stock 3.36 rear end. Give me a set of drag slicks and a deeper rear, and I'll guarantee u i'll be in the 12's. No offense to Norm, he's got a GREAT car, its just that I have a bigger cam and a professional head job(he did his by hand) and i've only got just over 200rwhp-which amounts to about 240 at the flywheel. To get near 270-300 at the flywheel requires much higher compression, a much bigger cam, and race gas-not a daily driver mind you.

Here's what i've done with mine, on the verge of being a race motor. A change to triple carbs and higher compression and i'd be there:

https://www.zdriver.com/rides/detail...x=10&vehId=549

nzz

You're right the ports are nice, big, and polished. Nice ride dude.

Guess I'd better start working on a new motor :-)

Amber

tyco1983

Nzz-
I like your z alot. I've always had a thing for those European tailights and the JDM mirrors up front. Clean and white-nice. I'd like to get a pair of those tailights too but all my money seems to somehow disappear into those 2.8 liters up front

nzz

I'd never noticed the different tail lights before. Also, yours has those little indicator lights on the side. Mine doesn't have those...instead the front park lights flash white for the turning signal and the back has an orange one. I must put up some more pictures...the mags are stock standard but apparently quite rare. And the old girl is right hand drive. When I come to the states I might get me a lhd one to cruise in :-)

Right...time to go and test her out now :-) cu

yo2001

Tyco, what your best time? and mph?

AllmyZs

Well I guess it is who you know. I am not building mine for the qaurter I can care less how fast you can drive a straight line I want to handle. Me and a few friands are rebuilding a 79ZX block from the ground up. I dont know the specs that is The shop owners job but when i am done i will relay them to you. 250-275 HP is not as hard to reach as you think. No you cant daily drive the thing it is not being built for that ( that is what my 81ZX is for) My 78 is only for Road racing and car shows. I have done a lot of research on parts and me and my friend think if done proper 250-270HP is not hard to get. Now how long it holds togther for who cares as long as I take it one race at a time.

Gotta get my Z's

tyco1983

Actually, if you are talking rear wheel hp-then yeah, it is as hard to reach as i think. My buddy does all the port work for Sunbelt Racing-the most noted z shop here on the west coast, rated with Rebello-their full out 2.8 liter race motor with 14:1 compression, triple TWM induction, a fully hogged out head, HUGE cam, all the works puts out a maximum of 234hp to the wheels on the chassis-jet dyno. Out of pocket, that motor is worth probably $20000-$25000. Maybe you guys have some magic that Sunbelt is unaware of?

nzz

Maybe it comes in a little blue bottle?

240z

Or maybe it looks like a hairdryer lol....

Gavin,
Melbourne
Australia
73' Datsun 240z

awd92gsx

I think if I spent $20k on an engine to produce a maximum of 234RWHP I'd probably commit suicide.

A turbo engine producing the same amount of hp will not only be cheaper, but will last longer, too.

Bill
77 280Z
www.dsetuning.com

tyco1983

Oh there's no doubt-I would never spend that much on a motor, but you have to understand that the motor is built for SCCA roadracing and must comply with certain specs, so for certain classes a turbo isn't legal.