Went to the dyno today...graph inside

[Rock777]

I got a dyno tune done today at PurPerformance in St. Charles MO and am very happy with the service and also my results. It was 95 today with a 105+ heat index, so wasn't expecting record numbers.

My mods are in my sig, but keep in mind this is with a 8.5/1 compression motor. Final numbers were 288/288 My base pull was 267/272 and my A/F was 10.0/1 , obviously pretty rich. The increase on the total area under the curve was pretty impressive though, at one part there was a 36 hp increase. (don't have base pull graph, but saw it at the dyno). My last time at the track I trapped 100 and 101 so I knew something was up, hopefully the next trip results better. On a cool day, it should get close to 300, so I'm happy considering my engine thinks I'm stupid for running it without a blower anyway. :bash:

The one thing that leaves me scratching my head is the tq and hp curves. Notice how the tq curve falls off pretty quickly after it peaks at 5200, while the hp hits 5200 and stays flat til he lets off. I'm not sure if this is something I should be concerned about as far as leaving power on the table, or if it's just how these motors, or my particular combo ended up.

Comments welcomed....:beer:

 

[PSUCOBRA96]

it does look strange, your HP hits the same wall as your torque, kinda weird too is that it stops making peak power at 5200 rpm, which is way early on a mod motor, was he having an issue getting a good reading? with the 03 heads it should do well in the torque and hp department, but then again with the sacrifice in compression you are leaving a couple of percent worth of power on the table.

 

[Wynn]

That curve looks way weird. What gear did you do the pull in? I'm looking at my NA graph, and the hp should continue to steadily climb- not a real steep line, but it shouldn't flat-line either. Also my torque drops off too, but it does it more steadily. Your torque curve looks like it's taking a ride down an escalater after 5250.

Good numbers, but it seems that there was some kind of issue. Your power looks like it still wanted to climb a little bit.

 

[Rock777]

it does look strange, your HP hits the same wall as your torque, kinda weird too is that it stops making peak power at 5200 rpm, which is way early on a mod motor, was he having an issue getting a good reading? with the 03 heads it should do well in the torque and hp department, but then again with the sacrifice in compression you are leaving a couple of percent worth of power on the table.

I am happy with my peak torque and it seems to peak about where I would expect it to, just odd that it falls off so sharp. He said everything looked good, getting plenty of fuel, but even he said it was weird, just couldn't put a finger on it. Only thing I can think of is if my intake tube is restricting at some point. It is basically a 9" S&B filter going through a straight 3" pipe, then into a rubber elbow. I would think in this N/A application, this would flow plenty.

That curve looks way weird. What gear did you do the pull in? I'm looking at my NA graph, and the hp should continue to steadily climb- not a real steep line, but it shouldn't flat-line either. Also my torque drops off too, but it does it more steadily. Your torque curve looks like it's taking a ride down an escalater after 5250.

Good numbers, but it seems that there was some kind of issue. Your power looks like it still wanted to climb a little bit.

He pulled it in third and fourth, just to eliminate that but the curve was the same in both gears. I agree, it looks like someone took a saw to the very top part of the horsepower curve, but the numbers pleased me given the HOT temps and low compression.

 

[luke87gt]

Post the SAE numbers with level 5 smoothing...

 

[Rock777]

Post the SAE numbers with level 5 smoothing...

Yeah, you're looking at the only graph I got.....

 

[jakesspv6]

better numbers than i got. how are they so high with a 8.5:1 motor?? congrats.

 

[Rock44]

better numbers than i got. how are they so high with a 8.5:1 motor?? congrats.

Same thing I was wondering, 288 with 8.5 NA compression out of a 4.6...VERY nice. It was not only hot as hell today, but humid as hell as well, not sure how much that affects anything (dyno experts?). I'm sure he monitored the timing and made necessary changes, but is it possible that the computer is pulling timing where the HP curve flatlines? Either way those numbers are great, and I am no dyno/graph expert, just throwing possibilities out there. Fuel is good, you don't really have any restrictive parts, exhaust is good. I wouldn't worry too much about at what RPM the #'s are, they are good. The only thing that could maybe possibly affect things is the degree at which your cams are set, how much overlap, etc, but once again that is straight out of my ass since I've never turned a wrench on a mod motor. I'm impressed either way.

 

[gq916]

post the sae numbers with level 5 smoothing...

+1

 

[Rock777]

Same thing I was wondering, 288 with 8.5 NA compression out of a 4.6...VERY nice. It was not only hot as hell today, but humid as hell as well, not sure how much that affects anything (dyno experts?). I'm sure he monitored the timing and made necessary changes, but is it possible that the computer is pulling timing where the HP curve flatlines? Either way those numbers are great, and I am no dyno/graph expert, just throwing possibilities out there. Fuel is good, you don't really have any restrictive parts, exhaust is good. I wouldn't worry too much about at what RPM the #'s are, they are good. The only thing that could maybe possibly affect things is the degree at which your cams are set, how much overlap, etc, but once again that is straight out of my ass since I've never turned a wrench on a mod motor. I'm impressed either way.

I think when they tune it, their is no "computer pulling timing" cause they control everything. I asked that about the IMRC plug being left open and he told me he overrides it. Who knows though, cause it seems like something like that? Ben (tuner) suggested maybe its the way the cams were installed too, and it seems logical, but the motor is supposedly a 03 longblock straight from Ford. Though I guess it's possible that he took the heads off and degreed things differently. The previous owner actually was road racer, so it might make sense to have a long flat peak horsepower like that. I'll get ahold of him and ask. good points

+1

What exactly does the level 5 smoothing do? I know what SAE numbers are. I'll see if the tuner could possibly adjust to SAE and the smoothing and email it to me if it can help.

 

[PSUCOBRA96]

I am happy with my peak torque and it seems to peak about where I would expect it to, just odd that it falls off so sharp. He said everything looked good, getting plenty of fuel, but even he said it was weird, just couldn't put a finger on it. Only thing I can think of is if my intake tube is restricting at some point. It is basically a 9" S&B filter going through a straight 3" pipe, then into a rubber elbow. I would think in this N/A application, this would flow plenty.



He pulled it in third and fourth, just to eliminate that but the curve was the same in both gears. I agree, it looks like someone took a saw to the very top part of the horsepower curve, but the numbers pleased me given the HOT temps and low compression.

Not sure your getting what I am saying, looking at your graph the peak torque is going to suffer at the higher RPMs, but your horsepower shouldn't just level off like a rock at the exact spot the torque takes a shit, it doesn't make sense. n Not to mention the RPM at which the hp levels off is low for a mod motor, this isnt a push rod motor, these cars make their power in the upper RPM band. 5300 RPM shouldn't be your peak horsepower numbers

 

[97desertCobra]

better numbers than i got. how are they so high with a 8.5:1 motor?? congrats.

He has a full bolt on Cobra with C heads and a ported 01 intake and is making 288. Take a look at what the Mach 1's with all the bolt ons and ported intakes put down. 320is rwhp. The compression is costing him.

 

[Rock777]

Not sure your getting what I am saying, looking at your graph the peak torque is going to suffer at the higher RPMs, but your horsepower shouldn't just level off like a rock at the exact spot the torque takes a shit, it doesn't make sense. n Not to mention the RPM at which the hp levels off is low for a mod motor, this isnt a push rod motor, these cars make their power in the upper RPM band. 5300 RPM shouldn't be your peak horsepower numbers

Nope, I'm getting what you're saying, not sure what you're wanting me to say. My PEAK torque is pretty accurate, numerically and where it should be in the powerband relating to RPM, it's the torque AFTER peak that is odd. I agree with the rest of your comments, thus why I started the thread. Trying to figure out WHY my torque drops and WHY my horsepower levels out. I"m aware of it and I'm aware it's not the norm......:shrug:

 

[PSUCOBRA96]

what are the plugs gaped at and whens the last time the wires were changed, I assume its cutting out in only the higher RPMs maybe because of a fuel spark issue, unless the cams and 8.5 compression really just hit a wall at 5400 rpm but I would think it could pull another 600 rpm in the HP department. Your torque dropping off doesn't seem like a big deal to me, my dyno graph shows a loss around 40 torque starting at 5500 rpm, but obviously not as steep as yours.

check with the new edge guys too, they may have another idea since you have similar heads, that and a bunch of them have switched to upgraded heads.

 

[Rock777]

what are the plugs gaped at and whens the last time the wires were changed, I assume its cutting out in only the higher RPMs maybe because of a fuel spark issue, unless the cams and 8.5 compression really just hit a wall at 5400 rpm but I would think it could pull another 600 rpm in the HP department. Your torque dropping off doesn't seem like a big deal to me, my dyno graph shows a loss around 40 torque starting at 5500 rpm, but obviously not as steep as yours.

check with the new edge guys too, they may have another idea since you have similar heads, that and a bunch of them have switched to upgraded heads.

Honestly, I haven't checked the plugs or wires since I've got the car. The wires appear to be fairly new and since there was no missing whatsoever, I didn't give it much thought. I'm definitely concerned with the hp at this point as it appears the peak way too early, which more than likely means a restriction and it would have peaked higher and at a higher RPM.

I have started a thread in the New Edge section also. I thought about that today because I used to have a 99 and those guys were great, so started a thread today. Good thinking, thanks.

 

[Rock777]

A member on another forum stated that my curve is normal for having the 186 degree 03 Cobra cams, so I started looking for other graphs.
I found this graph while trying to find comparables. It's on an 03 and has some very similar characteristics: torque starts dropping quickly after about 5000 and the hp is relatively stable from 5k-6k rpms besides a slight dip....Interesting

http://www.fle-online.com/Dyno%20Pictures/Magnaflow/15447.jpg