I think most dynamometers don't have that really powerful fan that can recreate the volume of air that can get into the car at WOT on the dragstrip. Therefore, I don't think that most dynamometers will show any HP gains from basic air induction mods such as an aftermarket airbox lid and SSRA-type mods. Now, I've read that the optimal air/fuel ratio range is 12.9-13.1. When I get my car professionally dyno-tuned on a dynamometer with no poweful fan, should I aim for a 12.9 to take into account the air that will be taken in during WOT on the dragstrip? Also, I saw this old reply:

Posted as a reply by Colonel on 12/01/02:
Does the above reply mean that air induction mods won't show any actual HP gains on the dragstrip at WOT unless the PCM is modified to account for the extra airflow in? Thanks in advance for the info.

 

Interested in this too

 

that quote sounds like a car that leaned out and then started adding some fuel on top of the PE table to compensate.

I'm intrested in this as well but I'll be trying something out. I'm going to be using an Austrailian ram air setup on my gto which should show some good gains in hp/mph while moving. On the dyno I don't suspect it would register more than the next "air filter" setup.

However, I'll be trying something different. I'll be dynoing my car to make peak hp/tq with my LM-1 wideband in while adjusting fuel/timing on the dyno. Then it will be intresting to see what my wideband is reading on some pulls through 4th gear on the street. I gues the easiest way to show this is just to plot it in excell. Then I can try to richen the car back up where it was making peak power while on the dyno.

I tried something similar recently but it was just load based. On an average of 10 1-4th gear pulls I plotted in excell the car read 8-10mv leaner every gear on gears 1-4. I suspect it would be worse with my new ram air setup but only time will tell.

Dougie

 

most people aim for 12.6:1 at peak hp on a dynojet because they create less load then on the street or at the track and richer at peak tq...on the street on an na car I try to aim for 12.6:1 @ peak tq & 13.0:1 or a little leaner at peak hp.

 

This post needs more replies.

 

As long as the A/F is good on the dyno it should be good at the track also, the PCM should compensate for the differences in air temp, air velocity and air pressure.

 

All the dyno fan needs to do is keep the air temperature near ambient. It can’t increase ambient pressure. Dynoing your car in a NASA wind tunnel would not significantly increase engine airflow. The biggest cooling fan is not a little supercharger.

 

Ditto, that's why engines have Vacuum, and not boost (unless of course they're boosted to begin with).

So the only added effect that the fans at a dyno have is simulating the air that would normally cool down the engine at speed.

Nate