slate blue

Well I was lucky to be watching the Australian GP on the weekend and they were interveiwing head of Toyota's Engine department. They should the world's most advanced engine dyno. Truly amazing some of its capabitlities but one was very interesting to me. That is the power gained through ram air. I must admit I didn't think it would be the case, what do you guys think?

Cheers Greg

69gaugeman

at 300km per hour there is some effect of ram air... How fast are you going..

Rod

sublimate

It the thread title you say "COLD ram air", but in the poll you just ask about "ram air"?

Getting cold air into the intake is worth a lot, particularly in real world stop-and-go traffic.
Ram air is worth nothing on the street. On a fast track maybe a little, but the aerodynamics have to be just right or it's very easy to have it degrade performance.

nee.dragger

There has been a craze in the motorcycle world (Sportbikes) over the past few years to put ram air on a majority of production bikes. I read a few years back when this happened that ram air only has an affect above the speed of say 70 or so mph. Above that speed, it then creates about 10 - 15 hp over a normally aspirated engine. That works out to about a 7 - 10 percent increase. And for a liter bike, that is fairly significant. So, if you can get a 7 - 10 percent increase ina car, that might be considered significant.

Mongo

Like Sublimate said, you cannot make full effect of a Ram-Air induction system unless you're exceeding 175-180 mph. Putting a scoop on to direct the air may increase drag coefficient. Cold air is a great benefit since oxygen is more dense when it is cool, hence better combustion and more power.

hacker-pschorr

The poll is to generic. Ferrari found 75hp at 150mph+ on the 550 using the hood scoup. I'm sure an F1 car at 150mph is gaining more than 75hp from the scoup above the drivers head. On turbo / supercharged cars they are almost useless, except to provide cool air. Reason why CHAMP Cars never had over the head scoups - there were not necessary.

Daniel Dudley

Stock 928 unit is set up to draw air from a high pressure area at the front of the car and is a perfected design with the stock filter. We should sell them to the import tuners. As I understand it, on a hot day drawing engine air from an under the hood source can cost 10 to 20 horses on an American V8, negating the benefits of a cool looking aftermarket air filter.

944s and 80s 911 models can benefit from airbox mods, but not the 928 AFAIK. Feel free to correct me.

Mongo

Ferrari achieved that power by also changing the timing to compensate for the change in the A/F ratios on the 550 Maranello

hacker-pschorr

Good point Stig, I forgot about that.

Mongo

Si Si Senor

slate blue

The speed is upto 300 kph.

The gain is 1% at 300 kph, the engineer was quite impressed with the 1%. Which I must admit really suprised me. So ram air induction is not worth the effort. Certainly to suck cold air would be beneficial but I would imagine any ram air system worth it's salt would do that. The air box in an F1 car is a trade off between feeding the engine and not creating too much drag.

On that note, the S4 with it's closable flaps, what was its cd open and closed? I can remember seeing the figures just can't remember where.

Cheers Greg

mark kibort

The truth????

160mph ram effects is .36psi at a 75% effecient hood scoop, OUT of the boundary layer. (or maybe a good nose inlet) that goes down to .08psi at 80mph!!!!!

so, its much less than 1% gain

MK

Jim bailey - 928 International

Yes Ram air sucks...great marketing however it just cracks me up how nearly everything that looks cool and "race" just turns out to be rice !