Curiosity dyno pull
Thread Starter
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Curiosity dyno pull
Since a local Pep Boys grand opening celebration and car show was offering two dyno pulls for only $0, I couldn't turn it down. 
I'm often asked "How much HP?", so this was an opportunity to satisfy my curiosity and have an answer to the nagging question.
Kinda funny numbers though, but maybe due to the IAT pulling timing a little more on the first pull because of heat soak. With both pulls in 97* ambiant, I was already timing handicapped. I wish I had taken my computer to scan the pulls, so I could see what and how much it was affecting the results.
#1 - 410.8 HP @ 6200 RPM -- 435.2 TQ @ 4550 RPM
#2 - 411.8 HP @ 5450 RPM -- 443.9 TQ @ 4550 RPM
The HP curve flattened about 5500, then dipped slightly before moving back up when it passed 6000. Although I stayed WOT to 6500-6600, the results were shut off at 6200 both pulls. I suspect that the KR I occasionally get at 5300-5400 in 3rd gear, caused the dip. The second pull never recovered before 6200, which is why the reading is at 5450.
You can certainly see the point where the 3600 stall started to hook up.
I should probably create a couple alternate tunes for quick swaps and buy some dyno time on a cooler day to try to eliminate the KR. I usually depend on timeslip numbers for tuning, but I might just try the dyno one time. I suspect the HP numbers would be higher with cooler IAT and no KR, but 411 will answer the curious until then.
I'm often asked "How much HP?", so this was an opportunity to satisfy my curiosity and have an answer to the nagging question.Kinda funny numbers though, but maybe due to the IAT pulling timing a little more on the first pull because of heat soak. With both pulls in 97* ambiant, I was already timing handicapped. I wish I had taken my computer to scan the pulls, so I could see what and how much it was affecting the results.
#1 - 410.8 HP @ 6200 RPM -- 435.2 TQ @ 4550 RPM
#2 - 411.8 HP @ 5450 RPM -- 443.9 TQ @ 4550 RPM
The HP curve flattened about 5500, then dipped slightly before moving back up when it passed 6000. Although I stayed WOT to 6500-6600, the results were shut off at 6200 both pulls. I suspect that the KR I occasionally get at 5300-5400 in 3rd gear, caused the dip. The second pull never recovered before 6200, which is why the reading is at 5450.
You can certainly see the point where the 3600 stall started to hook up.
I should probably create a couple alternate tunes for quick swaps and buy some dyno time on a cooler day to try to eliminate the KR. I usually depend on timeslip numbers for tuning, but I might just try the dyno one time. I suspect the HP numbers would be higher with cooler IAT and no KR, but 411 will answer the curious until then.
Team Owner
Joined: Feb 2001
Posts: 27,235
Likes: 119
From: Short Hills, NJ
Since a local Pep Boys grand opening celebration and car show was offering two dyno pulls for only $0, I couldn't turn it down. I'm often asked "How much HP?", so this was an opportunity to satisfy my curiosity and have an answer to the nagging question.
Kinda funny numbers though, but maybe due to the IAT pulling timing a little more on the first pull because of heat soak. With both pulls in 97* ambiant, I was already timing handicapped. I wish I had taken my computer to scan the pulls, so I could see what and how much it was affecting the results.
#1 - 410.8 HP @ 6200 RPM -- 435.2 TQ @ 4550 RPM
#2 - 411.8 HP @ 5450 RPM -- 443.9 TQ @ 4550 RPM
The HP curve flattened about 5500, then dipped slightly before moving back up when it passed 6000. Although I stayed WOT to 6500-6600, the results were shut off at 6200 both pulls. I suspect that the KR I occasionally get at 5300-5400 in 3rd gear, caused the dip. The second pull never recovered before 6200, which is why the reading is at 5450.
You can certainly see the point where the 3600 stall started to hook up.
I should probably create a couple alternate tunes for quick swaps and buy some dyno time on a cooler day to try to eliminate the KR. I usually depend on timeslip numbers for tuning, but I might just try the dyno one time. I suspect the HP numbers would be higher with cooler IAT and no KR, but 411 will answer the curious until then.
I'm often asked "How much HP?", so this was an opportunity to satisfy my curiosity and have an answer to the nagging question.Kinda funny numbers though, but maybe due to the IAT pulling timing a little more on the first pull because of heat soak. With both pulls in 97* ambiant, I was already timing handicapped. I wish I had taken my computer to scan the pulls, so I could see what and how much it was affecting the results.
#1 - 410.8 HP @ 6200 RPM -- 435.2 TQ @ 4550 RPM
#2 - 411.8 HP @ 5450 RPM -- 443.9 TQ @ 4550 RPM
The HP curve flattened about 5500, then dipped slightly before moving back up when it passed 6000. Although I stayed WOT to 6500-6600, the results were shut off at 6200 both pulls. I suspect that the KR I occasionally get at 5300-5400 in 3rd gear, caused the dip. The second pull never recovered before 6200, which is why the reading is at 5450.
You can certainly see the point where the 3600 stall started to hook up.
I should probably create a couple alternate tunes for quick swaps and buy some dyno time on a cooler day to try to eliminate the KR. I usually depend on timeslip numbers for tuning, but I might just try the dyno one time. I suspect the HP numbers would be higher with cooler IAT and no KR, but 411 will answer the curious until then.
But that torque reading seems high to me, both pulls were done in 3rd gear I assume?
Le Mans Master
Joined: Aug 2007
Posts: 6,473
Likes: 297
From: Orange Park FL
Since a local Pep Boys grand opening celebration and car show was offering two dyno pulls for only $0, I couldn't turn it down. I'm often asked "How much HP?", so this was an opportunity to satisfy my curiosity and have an answer to the nagging question.
Kinda funny numbers though, but maybe due to the IAT pulling timing a little more on the first pull because of heat soak. With both pulls in 97* ambiant, I was already timing handicapped. I wish I had taken my computer to scan the pulls, so I could see what and how much it was affecting the results.
#1 - 410.8 HP @ 6200 RPM -- 435.2 TQ @ 4550 RPM
#2 - 411.8 HP @ 5450 RPM -- 443.9 TQ @ 4550 RPM
The HP curve flattened about 5500, then dipped slightly before moving back up when it passed 6000. Although I stayed WOT to 6500-6600, the results were shut off at 6200 both pulls. I suspect that the KR I occasionally get at 5300-5400 in 3rd gear, caused the dip. The second pull never recovered before 6200, which is why the reading is at 5450.
You can certainly see the point where the 3600 stall started to hook up.
I should probably create a couple alternate tunes for quick swaps and buy some dyno time on a cooler day to try to eliminate the KR. I usually depend on timeslip numbers for tuning, but I might just try the dyno one time. I suspect the HP numbers would be higher with cooler IAT and no KR, but 411 will answer the curious until then.
I'm often asked "How much HP?", so this was an opportunity to satisfy my curiosity and have an answer to the nagging question.Kinda funny numbers though, but maybe due to the IAT pulling timing a little more on the first pull because of heat soak. With both pulls in 97* ambiant, I was already timing handicapped. I wish I had taken my computer to scan the pulls, so I could see what and how much it was affecting the results.
#1 - 410.8 HP @ 6200 RPM -- 435.2 TQ @ 4550 RPM
#2 - 411.8 HP @ 5450 RPM -- 443.9 TQ @ 4550 RPM
The HP curve flattened about 5500, then dipped slightly before moving back up when it passed 6000. Although I stayed WOT to 6500-6600, the results were shut off at 6200 both pulls. I suspect that the KR I occasionally get at 5300-5400 in 3rd gear, caused the dip. The second pull never recovered before 6200, which is why the reading is at 5450.
You can certainly see the point where the 3600 stall started to hook up.
I should probably create a couple alternate tunes for quick swaps and buy some dyno time on a cooler day to try to eliminate the KR. I usually depend on timeslip numbers for tuning, but I might just try the dyno one time. I suspect the HP numbers would be higher with cooler IAT and no KR, but 411 will answer the curious until then.
Both of mine are spring/summer weather SD tunes. I am going to retune both in some 40-50 degree air so I can just flash the correct tune and adjust at the track from there.
Tech Contributor
Joined: Jul 2002
Posts: 14,949
Likes: 263
From: St. Louis, MO
St. Jude Donor '08
I was surprised when I took my street/track tuned car to the dyno. It made a nice difference in power.
http://forums.corvetteforum.com/c6-t...o-results.html
http://forums.corvetteforum.com/c6-t...o-results.html
I finally took my car to the dyno to see how much additional power I received from the circa 2005 AFR 205 heads my friend gave me last summer.
The results are in.
474/414 AFR 205 Heads
451/404 Stock heads
23/10 gains peak,
25+ torque gains under the curve
First some facts to consider in the interest of full disclosure for those pondering these numbers.
1. This was a different shop, same dyno. The last dyno shop I used has closed.
2. I am now running heavy repro 19x12 wheels with 345/30/19 tires vs. last time with stock wheels and non-runflat tires. Add'l weight of about 20 lbs per wheel.
3. Last time I had 3.90 gears vs 4.10's now, difference shouldn't matter much.
4. Weather was better last time, freakishly low 34% humidity for us and 30.34 baro 81 degrees vs 45% and 29.96 today and 77 degrees today. Correction factors should accomodate but I believe you make more power with higher baro and lower humidity despite correction factors. Uncorrected the results are 480/419 vs 463/414, note the smaller variance of 17/5. I picked a good day to dyno last time.
My biggest takeaway from this exercise was wow, dyno tuning is a lot more valuable than I'd thought. I've been tuning myself for years now and had the car pretty dialed in from tuning at the track, or so I thought.
But look at run 1 vs run 5 today - I gained over 20 ft lbs of torque nearly across the board from tuning on the dyno, taking out some timing and adding some fuel down low and adding a bit of timing up top! The dyno tuning gains are quite a surprise. Obviously I could likely get a few more hp if I leaned it beyond 12.5 AFR...but I have 61,000 trouble free miles on my daily driver and I'd like to keep it for another 61,000 miles at least!
I'll be eager to hit the track again. So far best run with the AFR's and the same tune as run 1 was a 10.95 @ 129 vs best previous in my signature.
A question arises as when my stock OE clutch with 61,000 miles and 462 runs to date will finally say uncle. Last event I had 3 runs, 1.57, 1.59 and 1.57 60's, still learning the new launch technique. So far haven't had the stones to do 100% throttle launches like last time, which was netting me 1.49, 1.51 & 1.53 60's.
Some graphs:
Uncorrected
Corrected
The results are in.
474/414 AFR 205 Heads
451/404 Stock heads
23/10 gains peak,
25+ torque gains under the curve
First some facts to consider in the interest of full disclosure for those pondering these numbers.
1. This was a different shop, same dyno. The last dyno shop I used has closed.
2. I am now running heavy repro 19x12 wheels with 345/30/19 tires vs. last time with stock wheels and non-runflat tires. Add'l weight of about 20 lbs per wheel.
3. Last time I had 3.90 gears vs 4.10's now, difference shouldn't matter much.
4. Weather was better last time, freakishly low 34% humidity for us and 30.34 baro 81 degrees vs 45% and 29.96 today and 77 degrees today. Correction factors should accomodate but I believe you make more power with higher baro and lower humidity despite correction factors. Uncorrected the results are 480/419 vs 463/414, note the smaller variance of 17/5. I picked a good day to dyno last time.
My biggest takeaway from this exercise was wow, dyno tuning is a lot more valuable than I'd thought. I've been tuning myself for years now and had the car pretty dialed in from tuning at the track, or so I thought.
But look at run 1 vs run 5 today - I gained over 20 ft lbs of torque nearly across the board from tuning on the dyno, taking out some timing and adding some fuel down low and adding a bit of timing up top! The dyno tuning gains are quite a surprise. Obviously I could likely get a few more hp if I leaned it beyond 12.5 AFR...but I have 61,000 trouble free miles on my daily driver and I'd like to keep it for another 61,000 miles at least!
I'll be eager to hit the track again. So far best run with the AFR's and the same tune as run 1 was a 10.95 @ 129 vs best previous in my signature.
A question arises as when my stock OE clutch with 61,000 miles and 462 runs to date will finally say uncle. Last event I had 3 runs, 1.57, 1.59 and 1.57 60's, still learning the new launch technique. So far haven't had the stones to do 100% throttle launches like last time, which was netting me 1.49, 1.51 & 1.53 60's.
Some graphs:
Uncorrected
Corrected
Last edited by Joe_G; Oct 7, 2012 at 04:35 PM.
Thread Starter
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
All the performance mods are in my profile.
It was a portable unit set up for the day in their parking lot. The printout has no name, but the results were worth only slightly more than the cost.
4th gear (1.15 to 1). I'm kinda thinking TQ was high too, but if the possible KR existed, the HP would have been higher to make the TQ number more reasonably in line.
It was a portable unit set up for the day in their parking lot. The printout has no name, but the results were worth only slightly more than the cost.
4th gear (1.15 to 1). I'm kinda thinking TQ was high too, but if the possible KR existed, the HP would have been higher to make the TQ number more reasonably in line.
Thread Starter
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Here's the chart, so you can see what I meant about a HP dip.
I can't say I have a lot of faith in the numbers, but the general idea is enough to make me get a little more serious about my tune.
I've made a few changes since last year and starting a couple more right now, so a few TnT nights are needed before I'd consider hitting a dyno.
I can't say I have a lot of faith in the numbers, but the general idea is enough to make me get a little more serious about my tune.
I've made a few changes since last year and starting a couple more right now, so a few TnT nights are needed before I'd consider hitting a dyno.
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Drifting
Joined: May 2005
Posts: 1,655
Likes: 8
From: Avon Indiana
St. Jude Donor '09
Interesting...... What kind of times does your car run in what kind of weather conditions? That tq number if accurate it nice! How much timing are you running WOT?
I am thinking about strapping mine to a dyno in the next week or two. I have done quite a few things to it this year so it would be interesting to see what it makes. Timing is what I want to experiment with on the dyno. I currently run 28 degrees the entire quarter. Making a 2 degree change on a run might not show up due to differing track conditions. I always run Shell 93 in my car with the hope that whatever ethanol content would remain fairly consistent since that's what I tuned it on. Do you guys have a favorite fuel?
I am thinking about strapping mine to a dyno in the next week or two. I have done quite a few things to it this year so it would be interesting to see what it makes. Timing is what I want to experiment with on the dyno. I currently run 28 degrees the entire quarter. Making a 2 degree change on a run might not show up due to differing track conditions. I always run Shell 93 in my car with the hope that whatever ethanol content would remain fairly consistent since that's what I tuned it on. Do you guys have a favorite fuel?
Tech Contributor
Joined: Jul 2002
Posts: 14,949
Likes: 263
From: St. Louis, MO
St. Jude Donor '08
Interesting...... What kind of times does your car run in what kind of weather conditions? That tq number if accurate it nice! How much timing are you running WOT?
I am thinking about strapping mine to a dyno in the next week or two. I have done quite a few things to it this year so it would be interesting to see what it makes. Timing is what I want to experiment with on the dyno. I currently run 28 degrees the entire quarter. Making a 2 degree change on a run might not show up due to differing track conditions. I always run Shell 93 in my car with the hope that whatever ethanol content would remain fairly consistent since that's what I tuned it on. Do you guys have a favorite fuel?
I am thinking about strapping mine to a dyno in the next week or two. I have done quite a few things to it this year so it would be interesting to see what it makes. Timing is what I want to experiment with on the dyno. I currently run 28 degrees the entire quarter. Making a 2 degree change on a run might not show up due to differing track conditions. I always run Shell 93 in my car with the hope that whatever ethanol content would remain fairly consistent since that's what I tuned it on. Do you guys have a favorite fuel?
I gained 13/16 from a little dyno tuning when I put my new heads on. It felt & scanned fine on the street and track, but taking out timing and adding fuel down low gave me more mid-range and top end. I seldom see those areas of the RPM range at WOT on either the street or track, but it helped give the engine more power in the areas I do see.
Team Owner
Joined: Feb 2001
Posts: 27,235
Likes: 119
From: Short Hills, NJ
Sort of like what you (and others) are doing next month.
Thread Starter
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Interesting...... What kind of times does your car run in what kind of weather conditions? That tq number if accurate it nice! How much timing are you running WOT?
I am thinking about strapping mine to a dyno in the next week or two. I have done quite a few things to it this year so it would be interesting to see what it makes. Timing is what I want to experiment with on the dyno. I currently run 28 degrees the entire quarter. Making a 2 degree change on a run might not show up due to differing track conditions. I always run Shell 93 in my car with the hope that whatever ethanol content would remain fairly consistent since that's what I tuned it on. Do you guys have a favorite fuel?
I am thinking about strapping mine to a dyno in the next week or two. I have done quite a few things to it this year so it would be interesting to see what it makes. Timing is what I want to experiment with on the dyno. I currently run 28 degrees the entire quarter. Making a 2 degree change on a run might not show up due to differing track conditions. I always run Shell 93 in my car with the hope that whatever ethanol content would remain fairly consistent since that's what I tuned it on. Do you guys have a favorite fuel?
All AZ is stuck with 91 octane E10, so timing is 22-24* tops. I occasionally spike it with 100 at the track, if the KR is too much, but that's a crapshoot at best.
Drifting
Joined: May 2005
Posts: 1,655
Likes: 8
From: Avon Indiana
St. Jude Donor '09
In Phoenix with 1000-1600' DA, I normally ran 11.0x - 11.1x in early 2011. I went to Sacramento and had several 10's in -750 DA with a best of 10.82. Last racing season (late 2011 to early 2012) I didn't go a lot and the weather wasn't great either. I still ran low 11's in 2000' DA. I may run in a couple weeks, as it's cooling off now. We hopefully had our last 100* day on Friday.
All AZ is stuck with 91 octane E10, so timing is 22-24* tops. I occasionally spike it with 100 at the track, if the KR is too much, but that's a crapshoot at best.
All AZ is stuck with 91 octane E10, so timing is 22-24* tops. I occasionally spike it with 100 at the track, if the KR is too much, but that's a crapshoot at best.
