air intake-the final verdict

[ProtoRice]

Remember: the longer your intake, the better it is for high-RPM power, the shorter it is, the better for low-end torque. If you look at the variable runners on Ferrari F50's, you'll see that they lengthen at higher speeds and shorten at lower speeds. Dodge (3.0 V6) and Ford (SPI I-4) have similar systems that switch between 2 sets of runners based on RPM and throttle position.

[Gen1GT]

I just installed my RX7 AFM, and I got 2.5hp at peak, and 4hp at 7400rpm. I also got more power OVER THE ENTIRE REV RANGE. This shoots down that myth that it's only good above 6000rpm. I even got 4lb/ft from 2500-3000rpm. Some of that might have be due to the dyno tuning of the air/fuel mixture, and tightening the flapper door. Here's a hint to all you guys doing this mod...our cars like to run lean. Don't loosen the tension too much....

[Gen1GT]

Remember: the longer your intake, the better it is for high-RPM power, the shorter it is, the better for low-end torque. If you look at the variable runners on Ferrari F50's, you'll see that they lengthen at higher speeds and shorten at lower speeds. Dodge (3.0 V6) and Ford (SPI I-4) have similar systems that switch between 2 sets of runners based on RPM and throttle position.

Other way around. Longer, thinner piping=torque. Short, thick piping=hp.

The BP has dual length intake runners. The butterfly valves on the SHORTER runners open up at 5200rpms...or somewhere around there....

[LazerDKA]

Question: If going the "homemade" PVC route, what size pipe is needed? What do you use to attach the pipe to the engine, assuming the pipe is stiff? Is there a wall thickness minimum/maximum? I'm just curious cuz I don't have a welder so if I can get away with using plastic, that's what I'd like to do. However, I've only seen 1 intake mod on a Protege other than the ones in here, and it was metal and only an airbox replacement, the resonator and H-box were left in. Just a plate welded to the MAS. Speaking of which, the MAS is bolted to the airbox via a side inlet. Can I bolt a piece of plastic with metal backing to that with a hole in the plastic for the pipe that the filter goes on? Can I use PVC cement on the PVC plastic parts that I put under the hood? What size pipe is recommended? The cone filter I got has a 3" ID, but 3" PVC pipes look HUGE! If I drop to 2.5" will that be enough?

[LazerDKA]

Oh yeah, BTW, ProtoRice, nice car. I have the same year, same color. For now. 92 Protege DX

[Gro Harlem]

Buy one of these MX3 1.6 SOHC intakes...they will eliminate your H-box, but are COMPLETE and look to actually be MADE to fit. The mx3's have a very similar intake setup to the Protege/323 and should fit perfectly.



It is about $55 plus shipping on ebay, do a search and you'll find a bunch of auctions.


I also know some ppl who bought the 99-03 Protege intakes and bought a seperate adapter for the filter, and installed them, while still retaining the H-box.


if you do some research, you'll find that that H-box doesn't really make a hell of a difference on our cars. you might lose 2 ft lbs of torque under 2500rpm's...hardly worth keeping if you ask me. The MX3 isn't even equipped with one!

[ron_323F]

OK the line coming off the H-Box is your idle air inlet. DO NOT REMOVE IT OR YOUR CAR WILL NOT RUN!

I don't know why your car won't run if you remove the silencer.

sorry im a bit late on the subject, ive found this place very usful...

i have managed to get my car to run with the H box as you lot call it removed! just pluged the tube! but cold starts are a nightmare so its being put back on tomoro because it has lost a LOT or low end power, like it nearly stalls!

i should have some pics to post of my custom intake setup

i have what you know as an astina but its the same chassis n engine as one of its american conterparts

peace