N/A FI upgrade questions for newbie to Electonics

[Guest ackkkkmanp]

First off...thnx for this site to everyone who posts and writes..ive gotten a lot of suspension info from this site and its been great....now to the big headache for me..

i have a 77 n/a fi z and while it runs fine..would like the hp to match the g forces =0)..

ive purchased a weber big throat throttle body from ebay..connector piece from that to smaller hose on afm came with it... but nothing else..looks like its missing a bunch of connectors(ofcourse person i bought it from will not reply to email) but i will get it working ...My question is how can i modify the stock fuel injection?? ive heard of putting bigger injectors on but wont that just flood the motor?? second..and quite possibly the harder one..can the afm be modified??? ive heard of replacing it with the turbo afm but not sure exacatly what that would benefit.. im not a retired electical or engineering master as some of these people seem to be =0) no offense but some discussions look right out of NASA to me =0). so plz help a newbie.. i have the right start i think..hot spark.. big throat..cold air intake..what would be the next logical steps wth the questions posted above....BTW sorry this was so long .

Once again thnx to eveyone who posts to this site. i dont think enough kudos are given to the webmaster of this site either so ..."Bravo"

 

Paul

71 240z

74 260z "Ohhh so not stock"

77 280z

[johnc]

Unless you're willing to increase the engine's compression ratio, do some head work, change the cam, etc. that Weber throttle body won't give you any more horsepower. There really isn't a lot that bolt-ons will give you with the L6. I suggest you spend your time and money on making sure everything in and on your engine is in perfect shape and tuned correctly.

 

If you want more horsepower, you'll need to start looking at internal engine changes. Sorry, things are not as easy as the Internet or Sport Compact Car make them out to be.

[thefastestz]

Stock Zs already have cold air intakes.

The intake is in front of the radiator out of the engine compartment.

[Guest Nic-Rebel450CA]

ive heard of putting bigger injectors on but wont that just flood the motor??

 

I'll field this one. The answer is No. Bigger injectors allow a higher maximum amount of fuel to be delivered. This helps if your engine is able to pull in (or have forced in) enough air to actually make a the mixture get too lean because the injector cannot deliver any more fuel. The ECU will not let too much fuel into the engine (as long as it is working properly).

 

There really is not any benefit to upgrading your injectors unless you have significantly the airflow of the engine (such as adding a larger turbo on turbo cars). With the head characteristics of the L28, you are not likely to out-flow your injectors.

[z-ya]

The only problem with upgrading to bigger injectors is that there is no way for the ECU to know what the new flow rate is. It will run way rich. The stock ECU will continue to fire the injectors at the same duty cycle as with the stock injectors, but much more fuel will enter the cylinders because of the increased injector flow rate. The stock ECU does not have an O2 sensor, so it cannot compensate for bigger injectors. Even if it did, chances are that it couldn't compensate because the mixture would proably be out of the narrow mixture band a narrow band O2 is capable of taking accurate O2 readings within.

 

Pete