Best Compromise ?

[Guest Anonymous]

I'm looking for information and advice on building a Z motor.

 

I don't want to do a V8 conversion but I want enough motor to keep up

(or at least look respectable) with the stock V8's (Firebird, Corvette etc) off the line

at a light or on the highway. Is this possible without spending huge bucks and radical

alterations?

 

This will be a street only car, no drag strips or track racing and I only plan on running

the car 6 months out of the year due to winter. I have other vehicles so this new one I

plan to build can be slightly impractical!

 

I'm given a choice of rebuilding a L26 with early SU carbs '74 260 coupe or

starting over with perhaps a L28 EFI T3 Turbo motor. The EFI Turbo makes me a little

nervous because I don't know much about them, but I think that may be the only way

to get serious HP without a V8 conversion.

 

In either case I was thinking of a 5 speed (280Z), a R-200 4.38 LSD, and road

race suspension.

 

When rebuilding either of these motors, what kind (brand name, type of metal, price)

of motor parts (crank, rods, pistons, cam kit, flywheel, etc) and machine work

(balance crank, bore to what over, port, polish, mill, etc), is recommended?

 

I'm not a mechanic but I have rebuilt my stock 74 260Z 12 years ago on a poor

students budget... and it still lives. I hang out with some mechanic buddies but they

all work on V8 Chevy Ford stuff and frown on my Jap rice rocket so they are not much

help. So the point is I sorta know Z's. I would feel comfortable with any sort of nuts and

bolt job on it and can part out the block and head work. I just want to know what the

appropriate things (parts and machining) are to do or have done with the motor.

 

I know there are many different ways to get power from an engine and it often boils

down to some sort of compromise.

 

Any ideas?

[pparaska]

A JY 280ZX Turbo motor, etc. is going to be the best way to get an L6 to run with late model V8 GM stuff. You'd have to build a super expensive peaky NA L6 to do that.

[DAW]

Hands down: 280ZXT motor, with the complete wiring harness & ECU & sensors. Add an intercooler and compressor bypass valve and start working on brake upgrades.

DAW

[Mack]

Just ask Norm what he has done, as i recall, he hasn't done much to his motor to get his 240Z into the 12's. that should be more than enough to embarass some GM 350's, as long as its not a new vette. and if you REALLY wanna blow them away, put in a skyline motor. that would run you about 5 to 6 large tho. happy hunting!

 

McAdam

[Dan Baldwin]

I've been looking to buy a '94-'97 Z28 M6, and all I have to say is they feel SLOW compared to my '71 3.1. It's a track/street compromise car, but does have a few $$ in it.

 

I'd say your best bet is to find a 280ZX turbo and transplant the motor, or rebuild an L28 as a 3.1 liter with 10+:1 compression. Both routes could be pretty reasonable $$ to start out, would have excellent low-end torque, and have a lot of potential for good horsepower and better power/weight than a V8 F-body given some further mods.

 

I would NOT go with a road-race suspension on a street Z. Will cost you for coil-overs, and you'll hate the ride and never get to fully utilize the full handling potential. I just went with stiffer springs, sway bars, and adjustable shocks, and the handling is still a lot better than quite a few track-only cars at the race track. And is somewhat tolerable on the street, too.

 

4.38 gearing sounds like a lot more than you'll need, particularly with a 280Z 5-speed. I've got more than enough torque to boil the tires with a 280ZX 5-speed (much taller 1st gear) with a 3.70 (come to think of it, I did with the old 3.36 diff, too). In future, I might go to 3.90, but I doubt I'd ever go to 4:10s, even strictly for roadrace.

 

As far as parts sources, Nissan is the source for 90% of what you'll need for a hot N/A motor. No Dart, Feulling, Edelbrock, Weiand, yadda yadda yadda stuff available for an L6 anyway.

 

Don't let your V8 mechanic buddies work on your motor, go to someone w/ extensive L6 experience.

 

Have fun!

[pparaska]

Dan, I'm stealing another thread, but I don't seen how coilovers really make a car rough riding unless you put stiff springs in. And you can get a wide variety of rates with coilovers. I admit camber plates will make it harsh though.

[jeromio]

I agree with Pete on the coilovers. A complete coilover package is really not much more expensive than new springs. But you can choose from way more rates and ride height is completely adjustable. Most setups retain the original isolator, so it's no more or less harsh than stock.

 

As to the motor stuff, IMO, the equivalent costing/hp producing turbo motor will be much more streetable than the high compression N/A motor. Modern high comp. motors depend on sophisticated EFI for streetability on pump gas. Norm has certainly done amazing, low budget things with his N/A carbed motor, but I doubt his car is as easy to drive in traffic as an EFI L28 turbo.

[johnc]

I'm with Dan regarding coil overs, but for a different reason. They require much more maintenance than stock springs. Look at most coil over equipped vehicles after a couple years of use. The threaded collars are worn from the springs, aluminum spring perches are gouged, lower spring perches have their adjusting holes stripped... Plus, you have to clean the threaded collars frequently or you end up with a frozen "adjustable" perch.

[Guest norm[T12SDSUD]]

Actually, my car has no problems running in traffic other than the fact that you need to blip the throttle every once in while to keep the plugs from loading up when idling for long periods in traffic.I need to install an MSD to take care of that little distraction sometime.

 

Also, with my three core radiator the car never runs above 190 even when in heavy traffic.

 

My car is very torquey all over the place since my cam is a mild 272/282 .460 lift cam, so it has much more low end grunt than a Turbo car.

 

If you want a daily driver that will keep up with Camaros and standard Vettes, try a 10.5:1 CR L28 with a mild cam and dual SU's with headers and K&N air filters. Coupled with a 3.9 rear gear this combo will be good for low to mid 13 second 1/4 mile times in a lightweight 240Z.

 

Although if you have the money, a high boost Turbo would be my engine of choice.

 

Later,norm

[awd92gsx]

This is a problem I'm dealing with myself..

 

I've found out what I don't like about Z's. Too many options. With DSM's I only had to worry about 1 engine and 1 transmission. Now I'm finding with that Z's there are so many options that I'm going crazy trying to figure out exactly which way I want to go.

 

7MGTE, 2JZ, 350SBC, L28ET, 10:1 L28, RB26DETT, RB25DETT, and the list just goes on..and on...and on...

 

And then there's the rear end? 3.90, 4.11LSD, 3.54, does it ever end?

 

I'm going to be buying a L28ET that is already built here shortly (just waiting on the money to hit the bank...hurry up Uncle Sam!!) with JE's, balanced and blueprinted bottom end, Schneider racing cam, ported and polished hyd. P90A head, HKS gead gasket, T3/T4, etc...

 

Hopefully I can get this engine in the car soon after receiving it (may need a slight rebuild) and finally put my mind at ease about what I want to do.

 

I have a complete coil over suspension setup on my '77 280Z. It's very hard living in Phoenix, Arizona with a car that will probably outhandle some Porsches on a road course since we have nothing but straight roads here. The only time I ever even get to turn the steering wheels is when I'm making a 90 degree turn at a stop light...usually too much traffic to have any real kind of fun. Does it ride rough? Sure it does. But then again, I've never even ridden in, much less driven, another Z, so I have no idea how much stiffer it is than stock. All I was told was that the car was built as a road racer, and from what I've been able to tell certainly believe that!!!

 

I just want a solid 12 second Z that will kick butt at the local road course =o) That's not too much to ask is it?!?!?