conv90

Is there someone with a Ram air intake (they will be supposed to do a RAM air effect at high speed) with an SD car?.
Even If I don't believe that these kind of intake can really add a ram air effect, i'm courious to know if someone noticed increased MAP value at higher speeds. I'm referring to a value highr than the MAP value at KOEO.
Example:
Without ram air intake
If at KOEO ther is a MAP value of 98 KPA, you can see at WOT that the max MAP value is near to this value (say 97 kpa).
With a sorta of ram air intake duct
If at KOEO ther is a MAP value of 98 KPA if you can see that at WOT with higher speed the MAP reading is more or equal to 98 we can say that there is a RaM air effect.
How to tune a real ram air effect that goes to a value of map over the 100 value... this is another tread..
I can't see any VE table MPH related...
With Ram air effect I can have this situation:
I can be at WOT at 5000 rpm in first gear at 40 mph (without any ram air effect)
I can be at WOT at 5000 rpm in third gear at 120 mph (with Ram effect- different MAP value)...
-Thanks-
-Beppe-

Grumpy

For a true ram air to work, means a scoop that's not going to be street legal. Now, for just a cold air pick up, that can be worth a few HP. To make any sense of what your doing you need to mount a air temp sensor in the PLENUM. You have to source enough cold air so as to make a difference in the PLENUM, not just in the intake tract since so many intake tracts act as heat magnets, and in fact heat the incoming air.

FWIW, to really make a cold air system that worked really well on my car meant taking the hood off. And then the plenum air temps were only about 10dF different.

But, if your EGTs are kinda low anyway, then it really gets questionable if it's worth the time. I mention EGTs since for every 10dF change in plenum temp, is going to make a 10dF EGT change. But if your right on the ragged edge with EGTs then even a cool air intake is worth it.

RednGold86Z

iTrader: (1)

If you calculate the stagnation pressure, I get about .45 kPa available at about 60 mph, and 1.5 kPa at about 110 mph. Hardly enough to "boost" a manifold with an engine sucking behind it, but it will help air cross the filter and help with breathing.

Grumpy, I'm not quite sure, but at first glance I can't quite believe the 10° air tempt to 10° egt increase, assuming the same volume of air ingested. the colder air would have more mass at the same volume, and thus more energy to release during combustion. I don't want to hijack this thread or start another debate, but that's my first thought in regards to that statement.

Edit: I just had another thought on the ram air - since the air going into the duct has quite a bit of velocity at high engine loads, the relative velocity there is going to be down even further, reducing the stagnation pressure.