Interesting autospeed article on ram air intake

[SVOboy]

What do we think about this? Browser Warning

[Zukibot]

I think modifying the stock intake (like in that article) or installing a CAI, is a great way to improve HP & MPG's. Win-Win!

[johnpr]

interesting, i know that in the performance world ram air really doesnt make much of a difference, in fact a trans am ws6 (only real performance difference being ram air) is equal to a regular trans am on the drag strip.

but for fuel economy im sure minimizing the pumping losses must help but whether or not it is measurable is going to be another story.

[SVOboy]

Yeah, I'm not so interested in his lkm numbers since he's not very scientific, but the vacuum gauge read is interesting.

[tjts1]

I installed forward facing cold air intake on 3 cars equipped with warm air intakes from the factory. All 3 picked up fuel economy.

[Vince-HX]

I routed my intake to draw from right behind one of the inlets on my lower front lip and @ highway speed I saw 1 to 0.5 in increase in plenum vacuum. I assume I lowered my overall intake pressure drop by mounting a forward facing intake.

Ram air is kinda like using gravity to coast right?

[Vanner]

Tjts1, I'm not sure what you mean when you say "factory-installed warm air intake." Either way, I dont think a CAI could help. A CAI should bring in more dense air, which means the engine needs a smaller volume of it to produce the same torque, which means a less open throttle plate, which means pumping/efficiency losses. WOT is really the only time the engine takes advantage of the CAI, and indeed it should be more efficient at WOT, but I dont think WOT is applicable to a fuel economy discussion. The only two ways a CAI could improve fuel economy (not efficiency) is if the CAI actually brought in warmer air, or if you scaled down the motor to constant performance.

Vince, ram air is arranging the intake system to take advantage of the velocity of the incoming air to artificially "boost" the engine. Unfortunately it's been proven many many times that the effects are negligible until at least 130-140 mph. Or what the article says, I didnt read it.

I made some pretty broad claims here, let me know if im wrong.

[SuperTrooper]

Originally Posted by johnpr

interesting, i know that in the performance world ram air really doesnt make much of a difference, in fact a trans am ws6 (only real performance difference being ram air) is equal to a regular trans am on the drag strip.

but for fuel economy im sure minimizing the pumping losses must help but whether or not it is measurable is going to be another story.

WS6 TAs made 15 more HP and 25 more lb/ft of torque than a regular TA. In stock form they were 1-2 tenths quicker in the 1/4 mile.

Any time you reduce negative pressure in the manifold, or even turn it into positive pressure, pumping losses must be reduced. I wish the author of the article had finished testing for fuel economy before publishing the article. Right now it's just kind of a tease. I'm curious how the ECU will react to what might be unusual ratios of MAP vs TPS. If this were a MAF controlled engine the results would probably not be positive, mpg wise.

[johnpr]

Originally Posted by SuperTrooper

WS6 TAs made 15 more HP and 25 more lb/ft of torque than a regular TA. In stock form they were 1-2 tenths quicker in the 1/4 mile.

I'm aware of what the factory rated them, the truth is you put an un-modded t/a next to a ws6 and race them and there is no definate which is the faster car. this has been debated time and again on ls1tech.com and each time it comes out the same - they are equal cars.

[garys_1k]

Likely good for peak HP, but when FE driving you target the minimum power needed to drive your route. That means lower manifold pressure, obtained via whatever combination of partly closed throttle valve and upstream restriction gets you to that needed manifold pressure.

Reducing upstream restrictions just means you'll hold the throttle closed more, and increasing upstream restrictions means you'll hold the throttle open a bit more. The end result is the same.

Back in my max. HP days I played with that sort of ram air, but just like the equations say, there's pitifully little pressure available from forward speed until you exceed about 90 mph. In any case, for hypermiling, it's a waste of time.