350 not good enough

[BAlford]

We have a 1982 280ZX with a stock 350, a turbo 400 and the stock 280ZX rear end. The car sold new with a automatic transmission and was a turbo. I do not know the rearend ratio. The car will hardly spin the tires. At 3000 RPM we are doing 60 MPH. You can see the specs and pictures of the car as we bought it a year ago at:

 

http://www.waskomtexas.com/zcar/

 

The blower was removed before we bought the car and a quadra jet carb installed. We have spent a year getting the car back on the road. We have spent that time rewiring, putting the original dash back in the car, and upgrading the sound system and reinstalling all of the other components that were removed to make a show car out of it.

 

We plan to drive the car in our local area, no long trips, say 50 miles. We want it to be impressive with the hood up and at a stop light. We have no plans to drive it 150 miles an hour. We would like to get 12 or 15 MPG on gas. The car is an eye catcher but the motor is sick. We are ready to rework the drive train. We have a spare Chev 350 engine that we plan to rework while driving the car with the existing engine. We plan to use the same exaust system and transmission. We are thinking about a Holly kit, cam, heads, intake and about a Holly 650 double pumper. We can spend someplace around $2500.00.

 

Any suggestions?

[383 240z]

if the blower was used on the motor you are using it mostlikly has a dished pistons. low compression

and high performance just don't go together get a new set of slugs and you should be were you want to be. While you are at it I would make sure your converter matches you motor (the stall speed will be different on a blower motor) then with any extra money you have please find an overdrive trans you mpg will go up and will be a lot easyier to drive on the street. just my thoughts. Keith

[Guest greimann]

Ditto on the pistons and overdrive transmission. A Holley kit will probably get you 350 hp or better and should give you pleanty of go and adequate MPG.

 

The rear gear is most likely a 3.54.

[BAlford]

We have not ran a compression test yet. We have only driven it 500 or so miles since we got it running, that will be my next step. Would any one have a blower that they would part with, but how about running my alt and A/C comp? Would putting a blower back on the car improve the gase milage?

[BAlford]

We have not ran a compression test yet. We have only driven it 500 or so miles since we got it running, that will be my next step. Would any one have a blower that they would part with, but how about running my alt and A/C comp? Would putting a blower back on the car improve the gase milage?

 

We have another 1982 280ZX parts car. What would the rear end ratio be?

[BAlford]

We have not ran a compression test yet. We have only driven it 500 or so miles since we got it running, that will be my next step. Would any one have a blower that they would part with, but how about running my alt and A/C comp? Would putting a blower back on the car improve the gase milage?

 

We have another 1982 280ZX parts car with a standard transmission. What would the rear end ratio be?

[grumpyvette]

BAlford

the guys are correct, if that motor was set up ideally for supercharger use the static compression was down around 7.5:1 and the cam dropped that to a dynamic compression ratio of about 5.7:1 its no wonder the non-supercharged performance leaves something to be desired, install a 383 rotateing assembly with a set of 10:1 compression pistons,5.7" or ideally 6" rods and the longer 3.75" stroke crank, install a #114142 hydrolic lifter cam and pocket port the heads and you won,t believe its the same car!!!! this makes a good daily driver combo with lots of mid range power but without any daily driver problems (do a search on 383 rotateing assemblys, or 383, or rotateing assembly)

[BAlford]

We do not know if it was "set up for a supercharger" or if the supercharger was just bolted on for looks, since all it had to do was look pretty for car shows.

 

If we change the transmission what would you reccommend. I wouldn' mind going to a standard tramission. However cost might be a problem.

[BAlford]

Would like some more input here. We will probably discard the engine that is in the car now. The reason is that we can contimue to drive the car while we build another and then just swap. For this reason we can do what ever we would like with the new engine.

 

I would like to keep the cost around $2500.00, for no real reason except it just seems silly to keep dumping money into the car.

 

We would be interested in good used engine parts, such as heads, blower or carb, or a manifold. If we could find matching parts. We will still rebuild the block with new parts. We are interested in your ideas on the engine parts that we need.

[Guest Anonymous]

If its not smoking or anything, put in a new cam and look for better heads and intake and that'll wake it right up. You should be able to do all of what I suggest easily for your budget, if it needs a rebuild, you can still pull it off, but sharpen your pencil to pull it together in budget. Just an opinion.

 

Regards,

 

Lone

 

Personally I'd put a holley supercharger on it but a lower profile one to get a more moderate hood back on, plus you get the performance back, theres nothing wrong with having a blown V8 in a Z.

[Guest Drewz]

Do a compression test to see what you are working with first. If it is a tight motor the compression will be low if it has "blower" pistons or a REAL smog motor but either way smog or "blower"pistons the comp. ratio will be too low to do much without replacement of the slugs or addition of small chambered heads. IMO'S!!!

[BAlford]

Another question ! We ahve a complete 1982 280ZX parts car with a standard transmission. Could we use the standard z transmission with a rebuilt 350 engine. would it blot to the 350 and would it take the new power?

[utvolman99]

You cant use the T-5 from the ZX. Not unless you like installing a hand granade behind your engine. The first time you dropped the clutch would be like pulling the pin! If you want to go manual, you could either go with a T-5 from a V8 car or a T56 six speed.

As for the engine, I would suggest rebuilding the one you have. There may be some good components in that mill already.

[Kevin Shasteen]

BAlford,

 

What the other guys are trying to say is that this engine is most likely a perfectly good engine. The problem you currently are experiencing in the way of "The Lack of Power" is due to a supercharged and turbocharged engine's having to compensate for the extra "Pressure" and maximum increase in Airflow due to "Boost".

 

Because of that increase in boost once pressure rises; the initial Static Compression Ratio is low w/out boost msut be in the neighborhood of a 7.5:1 as Grumpy stated earlier, and the cam of choice for such a set up would leave you with the 5.5:1 or 6:1 Dynamic Compression Ratio as a result once the Intake Valve Closed on the Combustion Stroke.

 

These Comp.Ratios in and of themselves equal "Low Performance (actually; NO PERFORMANCE) up until the supercharger or turbocharger spools up to its maximum boost; then the ENGINE COMES ALIVE LIKE A BEAST WITH A BAD ATTITUDE.

 

So, now that you own the car and as you said ealier-the supercharger has been removed; what you are left with is a tame kitty cat that has forgotten how to purr; w/out the supercharger your engine is a mild mannered Clark Kent and the whole time you want a Superman. You cant remove the supercharger & expect a Superman level of performance w/out the appropriate Static Comp. and Dynamic Comp. You get the proper Comp's from the appropriate relationships between the components that make up your engine: pistons, cylinder head chambers & ports, Bore x Stroke w/the proper choice of a camshaft.

 

What I'm sensing from your posts is that you are equating "Non-Performance" with a "Delapidated Engine". When in reality, your enigne is not dead, it is only sleeping as a result from the supercharger having been removed.

 

If the engine doesnt smoke, in all likelihood, it is a perfectly good engine. You just have to decide if you want to put another supercharger back on it; "To bring it back to life" or rebuild the engine w/a higher Static Comp.Ratio to mach a higher Dynamic Comp.Ratio for a Normally Aspirated Engine.

 

If I were you (and I'm not) I would call the previous owner & find out all I could about the pistons-Dish cc's, Cylinder Heads-Port Volumes and their Chamber Volume cc's, the crankshaft-cast or steel(?) and what were the cam spec's. You would also want to know if the engine block had been specially prepped in any way. If the engine were prepped properly, chances are you have a very nice engine built for durability, which would be very much worth keeping and not scrapping.

 

Bottem line, do you want it to remain supercharged or are you wanting a Normally Aspirated engine. Either way, you probably have a very capable engine already sitting between the fram rails of your Z, its only a matter of [KNOWING] how the engine was prepped, what tolerances it was built to and what you plan on doing with it from here on out.

 

Call the previous owner and obtain as many spec's as you can. If the previous owner had an engine builder build the engine then you will want to contact that builder and ask the very same questions.

 

Kevin,

(Yea,Still an Inliner)

[BAlford]

When I am driving with the engine speed at 3000 RPM, I am doing 60 MPH. The rear end is stock, as best I can tell it is a 3.545 to 1 ratio. I have one out of a car with a standard transmission that is 3.900 to 1. If I am figuring right it will drop my engine speed at 60 MPH to 2726 RPM. Is this correct, dosen't seem like much.

[Phantom]

Your rear end math is backwards!! If you go from a 3.54 to a 3.90:1 rear end, the 3,000 rpm will go to 3,305. That is not the way you want to go unless you're really in to burning the rear tires off the car once you get the engine re-awakened. Concentrate on getting the engine where you want it and then research the differential. Mine is getting a 3.7:1 (removing a 3.90:1)tomorrow in preparation for the V-8. It will have a T-56 behind it, though, so at 60 mph it will be turning only 1501 RPM. That's the advantage of an overdrive (.50:1) transmission vs. one that has a 1:1 final drive ratio.

[labrat]

For what you are willing to put in it, another supercharger would be the way to go if the motor doesn't smoke or anything. Just with that addition, you should be way over the 450-500 HP mark (or else why supercharge it?). Used superchargers can be had on ebay for about half what you have, or you can go whole hog, buy a new one for a little bit more, and get a killer warranty on it. There are a lot of low-profile centrifigal superchargers out there, and a blown Z would "blow" my mind to drive...

 

Bill

[BAlford]

I can not get any information on the engine, except doing a compression check. Also the engine is rattling, I tought it was lifters but am now thinking that it is something else now. Still need to do a compression check.

 

Going back to a blower might be the way to go but can I still run the A/C compressor and does a blower run all of the time?

[BAlford]

I checked the compression on one cyl and it had 150 PSI. That doesn't sound like a low compression engine to me, am I wrong?

[Guest KraZ4spd]

OK Balford buy a copy of 'Chevy Small Blocks on a Budget'

HERE

And decide for yourself. This book has 10 different combinations all under $3000.00.

 

Or go to http://www.ryanscarpage.50megs.com/combos1.html