review of FRWilk's PowerProm

[97XRAY]

Well, at my piston's compression (10.x:1) I was at nearly 30mpg on conservative highway drives - pre-Wilk chip - and variably low 20s "around town". I am now at 12-20mpg, ranging from hardest driven to lowest torque-demand "highway-only-miles missions".

I'm not bothered by the number; I can always throw the old chip back in; I am FAIRLY certain that the chip is the origin of the change as I have done just that: swapped back for three tanks of fuel, milage went back up to ~24mpg. As soon as I saw the mpg reach a pseudo-pre-Wilk-value, the Wilk chip went back in. And I love it - let that be clear as day!

TCM:
What is your fuel consumption rate (per mile)?

[TCMdocs944]

I think highway is the low 20's but I know the o2 is bad. The po used to get 28 highway when the o2 was good.

I will run a test and get back to the thread. or start a new one.


12-20 is a really big difference.?

[CJFusco]

to answer someone's question about the o2 sensor, the effect that it has on the car is just the same fuel-air mixture regardless of altitude/temp/air condition. The reason for the O2 sensor in the first place is to optimise the engine for best emissions - that's why the sensor monitors exhaust, to make sure that the mixture is optimised for emissions.

Many 911 "tuners" switch from their Bosch Motronic/DME system to a carbeurator system to accomplish this exact same thing. With carburators, the air-fuel mixture is the same all the time.

btw, I haven't noticed a drop in my fuel economy. Perhaps I was running rich to begin with?

[97XRAY]

CJ
I think it may be partially that I had just rebuilt the motor (1.5 years prior to chip install), so I was combusting fairly efficiently, if that makes any noticable difference. And the higher compression pistons make some sort of a difference in combustion - but I'm not a pro on that one - possibly increasing the % combusted fuel?
Hell, I could have been running lean before the chip!

[bryanthompson]

Originally posted by ilikemy944
25-50% reduction in fuel mileage!?! Are you leaking gas?
I still get 480+ miles on a tank on the highway... and I play hard...

damn, brad, 480 miles?! That's insane. before i replaced my o2 sensor i got 300, with it replaced i've gone to 420, but 480?? Do you run to the last drop or something :P

[fast924S]

First off CJ is right, The O2 sensor is only for emissons, It tells the DME if the mixture is to rich or too lean, A power prom porsche ignores this and reads fuel and ignition maps off the chip per FR-wilks programming, this way you never get odd mixtures its always the same. Also why is everyone worried about MPG for, If your chipping your car you WANT MORE PERFORMANCE. There will always be a trade off when wanting more Performance, FI you want MPG's then ask him to make a chip that does that for you, and then you will notice a loss on performance.

[Zero10]

Mileage is very important to me, on one occasion, I got over 600 miles on one tank, and only used 60 litres.
Although the option to switch it back to the normal chip is nice....
There are times I would gladly sacrifice fuel economy for more power.
The valet option is useless to me, I never let anybody else drive my car, ever. =)

[RIchard944]

Zero10, mileage is not a problem. I did a little better on mpg on my first long trip with it. That is Better mileage. I see that I am not the only one.

Scott A. Harrison wrote
> It pulls much stronger in mid rpm range, gas mileage has
> improved a bit over what it was, and the extra power makes
> the car feel a lot more nimble than a stock 944na.

[TCMdocs944]

If your o2 sensor was fried in the first place I bet it does increase mpg. Smoother, more drivable = more fuel efficient in most cases.

[ilikemy944]

Bryan - best tank ever: 520 miles :O
That was from here to Florida
That included many 3rd gear exploits in traffic, as well as no sunroof and open windows with some a/c thrown in there too.

[bigyagi]

hmm, interesting comments about mpg. i have to admit that shortly after installing the chipped dme, i was doing all kinds of "tests" to ascertain how it would work out. during this time, i did notice my mpg drop a little, but it was only just noticeable. bearing in mind, that i was firmly planting my foot to the floor most of the time, and this showed up as less mpg. i think that when you get the chip, and see what it does for your engine's performance, its like a small addiction, as you take every opportunity, to let the engine rev hard, and enjoy the power delivery, the way it should have been!
after an extended time driving in power prom position, normal trips etc, i have to say that i really dont notice much of a difference. maybe a little less than i would get in standard position, but in my case, its hardly worth mentioning.
i suppose seeing that most cars are around 18 years old or so, and in all kinds of state of tune, you will see discrepancies like this, in mpg, and performance also.
FRwilk does say that you should make sure that your car is in a good state of tune before going ahead.
i'm with FAST924S on this one . the chip DOES make a great difference, and of course, you are going to use this option, so as you plant your foot, and get increased performance, so your mpg will go down.
incidently, a good test of how this chip performs, is a rolling one. you can choose any speed/gear, but i find 4th gear from either 30, or 40 mph, going up to 70, or 80 mph, really shows the difference. try it in 5th, from 50mph, up to 80, or so. that one will really open your eyes!
its handy to have the dual chip set up! only did that for emission testing, and now they have dropped it!!
last nb. there was a post a while ago, about the na mpg, and it seems even with the standard chip, that there is a wide difference from all owners.
install, drive, and enjoy!
bob.

everyone

[Zero10]

If my engine were in better shape I would be sold on the chip for sure.
However, at between 90 and 110psi on all 4 cylinders, it's just a little too worn out. To restore my engine to a state where the chip would be beneficial would cost me more than I'm worth, so that's out of the question I guess.

My hat is off to FRWilk for creating such a great chip though. Good job!

[serge944]

Originally posted by bryanthompson
damn, brad, 480 miles?! That's insane. before i replaced my o2 sensor i got 300, with it replaced i've gone to 420, but 480?? Do you run to the last drop or something :P

Lol, no kidding. I spoke to brad recently. His 951 "broke." Followed by "i think i ran out of gas."

[CJFusco]

i would have no idea how long a tank of gas lasts, because I always refil before it drops below 1/4

[scottmandue]

I have been reading this thread over the last few days and sorry but I'm too lazy to go back and re-read for the tech specs on FR's chip although doesn't it allow higher RPM and wouldn't that explain the lower MPG?

Also I think Todd did athe chip upgrade with an A/B switch so he could compare the new chip to stock (that crazy kid!)

[CJFusco]

yeah, the chip i bought allows for a 7500 RPM rev limit, i think. I don't think I've had it over 6000 so far, though... there is really no need, to tell the truth. Plenty of power in midrange now.

[TCMdocs944]

Yes, get your engine in reasonable shape before chipping...

That is my biggest delay.

[fast924S]

Yea the chip I have has no rev limit, HEHEHEHEHEHEHE its kinda cool when the needle goes into the black, But I wouldnt know or anything.

[CJFusco]

yeah, it also must be cool to pick up pieces of piston off the tarmac

[fast924S]

Well I only reved it there once in second gear, See I couldnt remeber where the Rev limiter was and when I looked down the Tach was berried so I just figured I dont have a limit, so Yea I gotta be carefull, But when project red blaze is done it wont matter