I have aeroforce gauges on my 2007 mustang gt. Lately I have had issues going through spark plugs every 5000 miles or so. Tillman speed, suggested I gap my plugs shorter (.30mm instead of .35) because the car is supercharged. I am running a range cooler plugs (HT0s). The car stopped missing, but I noticed after a couple of days that max hp on my aeroforces, form 530-570 depending on atmospheric conditions (70-95 degrees F), now (conditions even more favorable temps in 60's low humidity) it does not go over 500. Gas millage from 22-24mpg highway down to 17-19. City from 16 to 13.5mpg. Fuel pump voltage ok, fuel pressure ok. Supercharger works ok. I changed Tunes (have same tune 2ice with rear O2 on/off) reloaded, no difference. AF ratio seems normal, may be a couple of tenths of a percentage points richer than I remember.Exhaust system no leaks as far as I can tell. I do not hear any vacuum leaks, but i do not know how to detect them unless severe. Temps (block and coolant) are normal. I have not actually felt the power loss but I guess it may be hard to tell at these power levels. Fuel consumption tested on highway and it is real. Any thoughts?

 

Well, I want to say that your quoted power levels are pretty huge for [I assume] a stock block. To get that I see a very aggressive tune which could very well be eating plugs due to pre-ignition.
That said, I don't know the aero gauge you refer to but I remain reticent, in the least, at any of these plug in HP things... Too many variables at play.

Bear in mind of course that once you get it into your head that something is amiss, it's human nature to keep replicating scenarios to test and retest. I can see you standing on the gas more often than normal, trying to 'feel' a problem/lack of power. This behavior in itself will kill your fuel consumption..........

If you're sure the car is starting to lose it's pep, I would suggest a motor health check at a reputable tuner. At the same time I would definately want to back the tune out some, get another dyno tune, one which might help your motor last the distance because 530-570hp is too much.

 

Vacuum leaks can be detected by spraying carb cleaner over vacuum lines and hoses section by section with the engine idling. If there is a vacuum leak then rpms will increase momentarily as the engine burns the carb cleaner.

 

Thanks tom

 

Markus

The gauges, make a theoretical calc of the crank hp. On Dyno the car has made 462 rwhp @55f uncorrected. (when the aeroforces where showing abt 540's). Cops and 62mm TB made the gauges calculate abt 570 in similar temps. So suddenly they show 503 @ 65-70F, so not a dyno result, and not sure what data does the aeroforce gauges use from the car computer to calculate hp, but it does indicate that something is wrong.

 

500+ HP and 24MPG? wow.

I don't know about Carb cleaner but whenever diesel truck mechanics test for vacuum leaks they will spray a little propane over parts of an engine to see if there are any leaks and listen for a spike in RPMs. Im guessing the same could be done with N2O and gas engines. If you don't have any N2O contact your local dentist and get tell them your car needs some laughing gas. If for some reason THAT doesn't work, they use it as whip cream propellant. Buy some ready whip and spray it nozzle side up around any possible leaks. Huff the rest or enjoy a nice pie, your call.

 

I'm trying to wrap my head around this. Dyno proven numbers, you don't feel any loss of power, the car isn't acting erratically..but, a gauge (which is theoretical at best) is telling you that you are making less power..

The only thing pointing to an actual issue is your gas mileage, which could be a problem with your closed loop. Hit up your tuner, get back on the dyno, and verify whether or not a problem exists, or if it's all in your head(gauges). Chances are, if there is actually a problem, it will be in your first O2 sensor. Spark blow out may have dumped unburnt fuel into your exhaust, "possibly" fouling your O2 sensor, which would explain all of your issues, except the one where you don't personally feel any loss of power, but that is relative.

 

is the aeroforce gauge always consistent with the power levels?
hows your other readings like boost, fuel pressure?

 

As I mentioned initially everything reads normal except HP readings. recently I had my exhaust loose, to the point that passenger side side separated at the H pipe during hard acceleration. I was about ten miles away from home and no way to put it back together, (it was not dragging) so I drove the car home and put it back together. Could it be that the O2 sensor got fouled during that exercise? If it did, do I just clean it with some carb cleaner or what is recommended?

 

do you mean your rear O2 sensors?
if they are shut off, it shouldn't make a difference. i dont even have rear O2 sensors bc mine are shut off.
no CEL's?
and you are giving it WOT to the floor on the same road, no uphill/downhill?
did you change any parameters on your aeroforce?