I dyno'd yesterday afternoon. The changes between yesterday and my previous dyno were my test pipes, and my move to the colder iridium plugs. I really didn't expect the plugs to "make" power, but help with knock.

A guy over on my350z saw an increase of 8hp at peak when he moved from crawford cats to test pipes. I saw an increase of 4hp. But after the peak, I saw gains in the neighborhood of 10hp at some places. Granted, it's a very small rpm range; only about 800rpms or so. So the pipes haven't affected my daily driving, and I don't expect much of a difference in 1/4 traps.

My best numbers last time were 259/245, and my new numbers are 263/246.

One thing that I did not expect was effects of the test pipes on my a/f. Everything I've read has indicated a general tendency to run leaner, whereas I ran a bit richer. Also, the last time I dyno'd it was 102 degrees, ambient(compared to 76 degrees yesterday), which would leave me to believe that the ecu was dumping in more fuel in July; resulting in a richer mixture.

I have the run files, but I don't have the time to export the graphs just yet. I'll do that this evening or tomorrow.

On another note, I asked Blake(the owner) how 05/06 mustang gt's were fairing. He said they typically saw about 260hp peak, stock. So I asked him to bring up a stock gt run, and plot it against my run. The mustang makes much more torque, but it's hp curve looks identical to mine, but shifted lower in the rpm range. Quite interesting. I'll post that up as well.

 

Actually, I do have time to post the graphs.

The first graph is a comparison between of 5th gear pulls. The second comparison is with the mustang's pull.

 

If it was 102 at your last dyno and 76 now I think that helped more than anything else.

 

I disagree, simply from the fact that the lines are almost identical throughout most of the rpm band. The test pipes really didn't start showing any affects until the upper rpms, which is typical.

BTW - SAE correction was used, as normal.

 

Man do I wish these cars responded to removing the precats like the 95-99 Maximas did (~12whp/15wtq from 3000-6000rpms). You're right, the gains are isolated to the last 700rpms or so and not much is going on until about 6000rpms. The gains can't hurt, but they'll be hard to measure on the track. The gains might knock out 0.05 seconds or so. As usual, much thanks for actually testing your mods and putting all myths, rumors, heresay, butt dynos, etc to rest.

How is the car running with the new plugs?

The 05+ Mustang GT dynos are really interesting and it's sweet to see the comparision. I can't figure out why they only take the GT to 6000rpms though. I believe the rev limiter is somewhere in the 6200-6300rpm range. 260-265whp is pretty common for the GTs. Add an ECU flash, mufflers, and an intake and it's an instant 20whp/15wtq gain.

 

The car's running really well right now. There's almost zero audible knock, but that could be misleading. First, the exhaust *is* louder, and tone has changed, so if there is any knock it might be masked by the exhaust. Secondly, the car is running richer right now; that could possibly be due to the ecu reset I performed when I put the plugs in, only about 500 miles ago. The richer mixture might be enough to impact the knock.

Unfortunately, there are just too many unknowns to make any determination on the plugs, which is honestly what I was expecting. It's too early to make any judgments. If I had a logging tool that actually monitored the knock sensor, then we might reach better conclusions.

As for the mustang dyno, look at it's a/f. 12.0 to 1 is pretty rich for an NA car, especially bone stock. The ecu/o2 sensor feedback is pretty tight; there's very little a/f bounce after 3500 rpms. I bet with an ecu alone, you could get 20hp at peak. In fact, that's what Blake was telling me; a *good* tune will yeild around 20hp on his dyno, when he does the tune.

I still wonder why it runs so rich? I know it's optimized to run 87 from the factory. Maybe that has something to do with it.

Also, I need to spend some money on a utec. I'm pretty confident that if I have sharif do the tune, I'd pick up another 20hp or so; don't know about the torque. I'd especially like to get a real dyno tune to see what's going on with the knock and timing. If I saw those types of gains, that would put me at 280ish, give or take, on this dyno. That should be good enough for me to trap high 105s to 106s in the cold.

I tried to go to the track last night, but I had a head cold and decided I needed the rest. Maybe next week. If the temps are in the mid 50's, that should be good for a high 103 to low 104, and maybe a 13.6 if I can drive it ok.

Last time out, I trapped low 101's at 80 degrees, which equates to mid 103's at 50 degrees. But I know there was more left in it that night; I short-shifted most of the time, getting used to the new flywheel in the upper rpms.

 

I did the same thing. I replaced my Crawford cats with FI test pipes. This was in the middle of August in 90+ degree weather...who knows how hot it was in this dyno? Anyways, I dynoed at 9:45 am with the cats....241whp. I redynoed at about 3:30 with the test pipes....242whp. I forget the torque numbers.

I was really disappointed with my numbers, considerng my car is an '04 6sp. with Z-tube w/K&N, Crawford V5 plenum, Fast Intentions test pipes, HKS exhaust. I dynoed 233/230 stock... different dynos, different days I guess. I hope to dyno sometime in the winter to see how the temps affect the power.

 

Each 11F of air temperature [at the same barometer] changes density by 1%.
This has the ability to increase/decrease BMEP by 1% which translates into torque and thus horsepower by roughly the same amount [assumming ecu maintains the same AF ratio.

33F colder requires 3% more fuel for the extra oxygen to react.

 

This is just for comparison purposes - this is a plot of my last dyno, versus the dyno of the configuration in which I ran my 13.7@102.

The two plots are different dynos, but they were only a few hp off from myself, and other locals have observed.

 

And another comparison: same dyno, correction factors both the same: the first dyno was with the k&n filter, mrev, stock cats, and stillen exhaust.

The second dyno was with the stillen airbox and test pipes added:

 

Pretty decent. The 90% of the gains are focused from 5700-6700rpms, but you should still be able to take some advantage of them in the 1/4 mile. Why don't the runs go to the rev limiter?