Daeron

Here's the deal, I have a 1975 280Z that has stock motor, five speed, still fuel injected. Ive driven the car these last four years and it has served me faithfully, but it is high time i started making her pretty and much faster. I have figured out what i basically want to do, and thought I would submit my plan to the forum for nitpicking, advice, warnings, and general commentary.

I do not really know the history of the engine, and all plans are made with the thought that i may need to rebuild a motor at any point. My father and uncle have been playing with, and collecting these cars for thirty years so I am confident in my resources.

I want to put a K&N air intake on it and build an airbox to go around it to take advantage of the air flowing into that gaping maw :-D. Im thinking something like an aluminum mailbox with the bottom cut off, but fancier. Someone I know gave me an air flow meter that he had taken apart and manually advanced it a few clicks so that it thinks the meter is open further than it is; I don't know how much to trust this, but it seemed to make sense to me and it was free. Then go from that into a big bore throttle body, then.. stock manifold, injectors, any suggestions?

eventually id like to build an engine and put bigger valves into the head, maybe higher compression pistons too.. I could go turbo, but i would prefer all motor. i think. im still unsure of that.

I also have instructions for building a potentiometer to control the fuel mixture out of parts from radio shack; i thought this, combined with the described intake and a mixture gage might just make for a mean, all motor FI Z car.

i have motorsports 3-into-2 headers and 2 1/4" twice pipes/glass packs for exhaust.

thanks for reading the long post

Any thoughts or suggestions appreciated!!

theramz

Interesting concept! If I understand you, you're going to ram air into the intake which will increase with the speed of the car. You can increase the fuel as the air flow increases. A guy with a degree in thermal dynamics once told me that you can only ram air at about a 2-3 degree angle because it gets to turbulant and is not efficient above that.
BOOKS? Just try something new.

zguy36

Don't use the airflow meter that you buddy gave you. This will only give you driveability problems. By this, I mean that it will run too rich, all the time. You will not need the extra fuel with the modifications that you making. A better flowing filter will allow air to be draw into the motor easier, but will not have any effect on the metering ability of your current meter. Leave the meter alone, unless it is causing problems. Also, don't expect a large increase in power with just an air filter either. You're on the right track with more compression and porting. If you are really after power, go with a turbo. It is the best way to make a fast, streetable car.
-jeremy-

Daeron

the air flow meter was my biggest question; the guy that gave it to me had been doing some racing with his street car, so i assume it was probably mostly for that reason that he made the mod. my biggest question was whether that would complement the "big-bore" 60mm throttle body well or whether the standard AFM would do better. thanks for the replies.

Bleach

That mod will only richen your mixture slightly in the low and midrange rpms. With a stock cam, the short duration already cuts the air intake down at high rpms. (rich mixture)

The big throttle body will compliment the AFM and stuff nicely. To finish it off, you should also port-match the intake manifold at least where it meets the throttle body and then isntall a longer duration cam.

TEDS280Z

My 77Z is having problems. I replaced the air flow meter(the right one this time) and am still having intermittant problems. Sometimes the engine is acting as though it has a miss and is luging, other times runs like a dream. A parts guy at Nissan said to get a presurized injector cleaner done. Has any body had this problem and heard of this process?