View Full Version : Intake Q? MAS or SDS?

01-10-2003, 12:03 PM
Ok.. not wanting to thread jack ..
I had a few questions on the intake / fuelrail and then mass air flow vs. speed density..

First.. If I were to upgrade to the Greddy intake..
what fuel rail would i need to use? I see on the web page a fuel dilevery tube..
Now is that a direct replacement.. meaning I COULD use the stock one if i wanted.. or is it a MUST buy before i can use the intake?

Is that a top feed? side feed? and what are the advantages to each? OTHER than injector price..
meaning is there a performance benifit from one better than the other?

Also.. I know on a Power FC there are maps where you can convert to Speed density.. not sure if you need to add sensor or not.. but you are able to remove the MAS..
What kind of benifits and disadvantages are in doing this..?

I don:t really care about peoples preference on one or the other.. just actual benifits and disadvantage to each.

thanks for any and all responses but i figure when i get the power fc i might as well do couple other changes also..

01-10-2003, 12:35 PM
Not sure on the Greddy intake, but I can help you out on the MAS question.

First off, I believe only special tuner shop versions of the PowerFC can allow you to convert to speed density - it's not a native feature of the PowerFC.

That said, I really don't see a good reason to switch to speed density. The PowerFC directly supports all the Nissan airflow meters, up to and including the 90mm Q45 V8 airflow meter. If you're making enough horsepower to max out a 90mm MAF, my hat's off to you http://forums.freshalloy.com/ubbthreads/images/icons/smile.gif.

Speed density systems aren't all they're cracked up to be. The biggest problem is you have to have a constant VE for the engine - it has to know that to compute the volume of air. If you alter the VE, you have to retune the map. An airflow meter is directly measuring the airflow to the engine, so the ECU knows just what's going on. If you alter the VE by putting on a straight pipe or whatever, it should be able to compensate, provided the rest of the system is up to the task (big enough fuel injectors, fuel pump, etc.).


01-10-2003, 01:06 PM
no the greddy intake can be used with the stock rail the fpr will sit facing the wrong way but its not that big of a deal. I've got the stock fuel rail on mine now.