Printable View
I went up to Louisville this weekend to meet Chris Ludwig to dyno-tune the engine he just rebuilt for me. We were on a Mustang. Before I reveal the results, I thought I recalled a discussion of how to compare Mustang and Dynojet rwhp, but I can't find it. In the range we are talking about for a 2nd Gen., how many rwhp would think you should add to Mustand nos. to equate to Dynojet? FWIW I'm really happy w/ what we got. :happy204:
20 to 25 from what I have seen. Woops, went back and looked at last years dyno sheets. 200 hp on dyno jet was 185 hp on a Mustang, same engine and car.Quote:
I went up to Louisville this weekend to meet Chris Ludwig to dyno-tune the engine he just rebuilt for me. We were on a Mustang. Before I reveal the results, I thought I recalled a discussion of how to compare Mustang and Dynojet rwhp, but I can't find it. In the range we are talking about for a 2nd Gen., how many rwhp would think you should add to Mustand nos. to equate to Dynojet? FWIW I'm really happy w/ what we got. :happy204: [/b]
Over 15%?
I typed this up for another forum last year. Enjoy.
Preface:
Ok I'm going to supply some information based upon my 13+years of working with chassis dynos. I'm going to keep this as factual as possible w/ as little bias as possible, I invite any of the other dyno reps to posts or shop owners who have a dyno.
First off I will state my current position. I am the southeastern USA sales rep for Dyno Dynamics. In the past I have worked w/ dyno from various mfgs. All of these dynos I have had extensive experience with. Dyno Dynamics, Dynojet, Superflow, and Mustang. I have working knowledge of Roto-Pak, Dyna-Pak, Bosch, and Maha.
This is key, an number is just that, a number.
It doesn't matter wether a dyno reads 400hp on 1 mfg's dyno or 3 apples, 2 oranges, and a kumquat on some other mfg's dyno. A dyno is a tuning tool. The purpose of a dyno is to simulate real world conditions to help tuners. What is important is to see how change made to the vehicle affect it's power output. So your tuner makes a change and now you make 405hp or 3 apples, 2 oranges, and 2 kumquats.
A gain is a gain, a loss is a loss, period.
Numbers are only good for pissing matches and bench racing.
Now on to the comparison:
Here is how the various mfg dynos relate to one another. This is just a comparison of numbers output assuming the same vehicle on the dyno.
The industry leader in number output by far is Dynojet. Their marketing in the mid-90's specifically used the larger output numbers as a selling item.
Next is Mustang, generally about 7% less than Dynojet numbers.
Superflow is about 3% less than Mustang.
Dyna-Pak and Dyno Dynamics are about 3% less than Superflow.
Ok lets make this point again to make sure it's clear. The SAME CAR on the DIFFERENT DYNOS. So our test vehicle output on the various dynos are as follows:
Dyno Dynamics 200hp
Superflow 206hp
Mustang 214hp
Dynojet 226hp
This is assuming the dyno operator has not changed any of the parameters of the dyno. All of the dynos software incorporates parameters that are operator definable. These adjust the displayed power output. In other words the operator can "adjust" the output of the dyno to display any number desired. By adjusting weather station parameters, external corrections factors, inertia compensation, or any one of a dozen different factors the output number can be modified. The number can be modified to display anything from 10% of measure power to 300%. So our 200hp example vehicle can after a pull display peak power of 20hp or 600hp w/ just a couple of keystrokes.
Key Fact: Just because the dyno spits out a number, it doesn't means squat without knowing ALL of the correction factors.
Some dyno operators adjust the output of their dynos to closely match the highest numbers in the industry, Dynojet. This is not an attempt to defraud the customer. It is just that customers have a false notion that a bigger number means more power. But as you have seen, numbers mean nothing.
If anyone has any questions about dyno operations or which type of dyno is better or worse please start another thread & I will be more than happy to answer any questions.
Quote:
I typed this up for another forum last year. Enjoy.
Preface:
Ok I'm going to supply some information based upon my 13+years of working with chassis dynos. I'm going to keep this as factual as possible w/ as little bias as possible, I invite any of the other dyno reps to posts or shop owners who have a dyno.
First off I will state my current position. I am the southeastern USA sales rep for Dyno Dynamics. In the past I have worked w/ dyno from various mfgs. All of these dynos I have had extensive experience with. Dyno Dynamics, Dynojet, Superflow, and Mustang. I have working knowledge of Roto-Pak, Dyna-Pak, Bosch, and Maha.
This is key, an number is just that, a number.
It doesn't matter wether a dyno reads 400hp on 1 mfg's dyno or 3 apples, 2 oranges, and a kumquat on some other mfg's dyno. A dyno is a tuning tool. The purpose of a dyno is to simulate real world conditions to help tuners. What is important is to see how change made to the vehicle affect it's power output. So your tuner makes a change and now you make 405hp or 3 apples, 2 oranges, and 2 kumquats.
A gain is a gain, a loss is a loss, period.
Numbers are only good for pissing matches and bench racing.
Now on to the comparison:
Here is how the various mfg dynos relate to one another. This is just a comparison of numbers output assuming the same vehicle on the dyno.
The industry leader in number output by far is Dynojet. Their marketing in the mid-90's specifically used the larger output numbers as a selling item.
Next is Mustang, generally about 7% less than Dynojet numbers.
Superflow is about 3% less than Mustang.
Dyna-Pak and Dyno Dynamics are about 3% less than Superflow.
Ok lets make this point again to make sure it's clear. The SAME CAR on the DIFFERENT DYNOS. So our test vehicle output on the various dynos are as follows:
Dyno Dynamics 200hp
Superflow 206hp
Mustang 214hp
Dynojet 226hp
This is assuming the dyno operator has not changed any of the parameters of the dyno. All of the dynos software incorporates parameters that are operator definable. These adjust the displayed power output. In other words the operator can "adjust" the output of the dyno to display any number desired. By adjusting weather station parameters, external corrections factors, inertia compensation, or any one of a dozen different factors the output number can be modified. The number can be modified to display anything from 10% of measure power to 300%. So our 200hp example vehicle can after a pull display peak power of 20hp or 600hp w/ just a couple of keystrokes.
Key Fact: Just because the dyno spits out a number, it doesn't means squat without knowing ALL of the correction factors.
Some dyno operators adjust the output of their dynos to closely match the highest numbers in the industry, Dynojet. This is not an attempt to defraud the customer. It is just that customers have a false notion that a bigger number means more power. But as you have seen, numbers mean nothing.
If anyone has any questions about dyno operations or which type of dyno is better or worse please start another thread & I will be more than happy to answer any questions.
[/b]
Nominate for first poster of the decade award? Good stuff!
Nominated, and one vote for. That is the best short explanation of the differences in dynos I have seen.
Damn, Chris, I'm kinda afraid to even post this because it sounds so unreal.
My first dyno experience ever was in 8/05 when my car was running pretty good. At the end of Oct. w/o any changes I did my fastest lap ever at St. Louis. That was on a Dynojet and it did 168 on a hot and humid day. Not bad I thought for a 3-year old engine, albeit SpeedSource.
That engine lost compression 3/06 due to oil seals. Rebuilt locally it then did 164. :-( That one blew in July and Chris rebuilt it but it never made a dyno. It departed this life at the ARRC.
I took the entire car to Chris and he rebuilt the engine (apex seals and soft parts) and found and fixed some fuel and other nagging issues.
We put it on the Mustang at AutoMotion in Louisville Fri. Given the fact that the Mustang nos. would be lower than Dynojet, I was hoping for something above 160. Chris had done a good job tuning it up in his shop because the very first pull had that beat. It wasn't long before we had it above 170. The best power we got was 174 but that was too lean. We settled on a safe A/F that yielded 172 at 7027 rpm w/ 128# torque. Max torque was 134 at 6027 rpm. Using underpressure's conservative 7% differential, that's the equivalent of 185 on a Dynojet. Now, I just cannot believe that so perhaps AutoMotion has their dyno set a little high. I hope to actually put it on a Dynojet so we can see what the difference is.
Needless to say, I'm thrilled regardless! :D
that........is a lot of friggin power.
Quote:
Damn, Chris, I'm kinda afraid to even post this because it sounds so unreal.
My first dyno experience ever was in 8/05 when my car was running pretty good. At the end of Oct. w/o any changes I did my fastest lap ever at St. Louis. That was on a Dynojet and it did 168 on a hot and humid day. Not bad I thought for a 3-year old engine, albeit SpeedSource.
That engine lost compression 3/06 due to oil seals. Rebuilt locally it then did 164. :-( That one blew in July and Chris rebuilt it but it never made a dyno. It departed this life at the ARRC.
I took the entire car to Chris and he rebuilt the engine (apex seals and soft parts) and found and fixed some fuel and other nagging issues.
We put it on the Mustang at AutoMotion in Louisville Fri. Given the fact that the Mustang nos. would be lower than Dynojet, I was hoping for something above 160. Chris had done a good job tuning it up in his shop because the very first pull had that beat. It wasn't long before we had it above 170. The best power we got was 174 but that was too lean. We settled on a safe A/F that yielded 172 at 7027 rpm w/ 128# torque. Max torque was 134 at 6027 rpm. Using underpressure's conservative 7% differential, that's the equivalent of 185 on a Dynojet. Now, I just cannot believe that so perhaps AutoMotion has their dyno set a little high. I hope to actually put it on a Dynojet so we can see what the difference is.
Needless to say, I'm thrilled regardless! :D
[/b]
First I'd like to thank the acadamy for my award of best first post ever. :smilie_pokal:
Second congrats on the motor, regardless the numbers it sounds like it's going to be on the strong side of the bell curve.
I would definately suggest running the car on a DJ just to see what sort of DJ nubers you are actually putting down. I'm not familiar w/ that specifc Mustang dyno in Louisville. Is it an eddy current or intertia type? Here's why I ask...Mustang used to have difference correction factors betwen their 2 families of dynos. The intereia type dynos read on or about 3% less than a DJ while the Eddy current read the ~7% less. Why they did this.. who knows. Guessing to make their large roller inetia dynos read nuimbers like a DJ. But then used actual math to dervie number for the eddy current.
And just to throw more fuel on the fire.... DJ's use to have a factory tolerence of +-3% from the factory. Meaning 1 car could test @ 200hp, 206hp, 194hp on 3 different DJ dynos and that was considred ok by the factory. They have since closed up the toloerence to an advertised 1%. So even among DJ's it's best to pick one dyno and constantly use that one as your reference point when making changes.
Also here's a link to a story on how DJ came up w/ their correction factor years ago.
http://www.factorypro.com/magazine/Sports%...ne/scan0001.pdf
http://www.factorypro.com/magazine/Sports%...ne/scan0002.pdf
http://www.factorypro.com/magazine/Sports%...ne/scan0003.pdf
http://www.factorypro.com/magazine/Sports%...ne/scan0004.pdf
http://www.factorypro.com/magazine/Sports%...ne/scan0005.pdf
For those interested in the original thread I posted from earlier: http://www.my350z.com/forum/showthread.php?t=123014
I wouldn't be a bit surprised if your DJ numbers are in the mid 180s. Not a bit.Quote:
Using underpressure's conservative 7% differential, that's the equivalent of 185 on a Dynojet. Now, I just cannot believe that so perhaps AutoMotion has their dyno set a little high. I hope to actually put it on a Dynojet so we can see what the difference is.
Needless to say, I'm thrilled regardless! :D [/b]
Totally just rambling here, but it amazes me what we get out of motors in IT trim. Think about it:
2.4 liter in line six in the 240Z - 190-200 hp at the wheels!
1.3 13B rotary -- 180 hp at the wheels!
2.5 liter BMW in line six -- 205-215 at the wheels!
My car, 3.5 crap old V8 -160+ at the wheels, 200 tq at the wheels! At that is with an amateur build.
If you talk to any dyno guy/engine builder outside of the IT world, they would LAUGH at you saying you got these numbers out of .5 more compression, some port matching and exhaust. Just goes to show what smart people can do within the rules.
It's interesting that you have chosen the engines you have, as three of them fit into two well known categories that have been noted for reliable gains beyond the normal scope.
Let me guess, the Rover V8 is NOT one of them...lol...actually it should be because of the gains I get just from taking all the smog crap off of it.
If it is, then I would think you were talking about the Rover V8, the 2.5 BMW motor and the rotary.
The Z motors are pretty amazing too. They make nearly as much power as the Bimmer, with carbs. Z cars were still winning in S on occasion even with unrestricted Bimmers around. Hell, Chet wasn't THAT much faster in his orange BMW than in his orange Z.
In any event, sorry for the threadjack. Back to your regularly scheduled RX7 programming -- and thanks for the info above on dynos. Very helpful.
God, this kind of thread sure beats the hell out of arguing about ECUs or who had to pay what to go to an SCCA shindig.
DynoJet now makes Eddy Current dynos as well as the older inirtia dynos that I think you are all referring to here. Might want to start making that distinction. I've heard the DJ_Eddy is usually close to the output of a Mustang but have no personal experience with DJ.
I don't know anything about the dyno except that it was run by a lady named Cindy. Maybe Chris will weigh in since he is familar w/ these people.
Congratulations on getting the problems fixed. Look forward to seeing you on the track instead of sitting at my trailer door with a dead car. :OLA:
Automotion uses a 1750 Series Mustang dyno. It has 50" inertial rollers and an Eddy brake. While there are two local Dynojets we use Automotion almost exclusively for several reasons. The biggest one is their brake capability allows us more precision in tuning full standalone systems. Neither of the local Dynojets have bothered to upgrade to brake technology. We've also used the Superflow dyno at SR Racing in Lexington several times which is similar to the Mustang in configuration. For IT application the numbers between the Mustang and Superflow are usually within a few HP.
As far as numbers, we've seen cars turn higher numbers on Dynojets than this Mustang. However, in the end a number is just that.
Quote:
Needless to say, I'm thrilled regardless! :D [/b]
Nice to see a happy camper! There is nothing worse than a nagging problem (been there)! Best of luck this year, hope to see you doing well on the track.
Strangely enough I had the opposite reaction to the Dynojet vs. Mustang debate. Initially I went to a Mustnag dyno facility here in Indy anfd on my first pull it read 192HP. :rolleyes:
Without further tuning I took the car to a Dynojet facility and first pull got me 153HP. The Mustang place was having a hard time getting an ignition pulse so who knows what numbers he plugged in to get it to read 192HP. I can tell you that it certainly didn't feel like 192HP.
At the Dynojet place the tech opted to use the optical pick-up for an RPM signal which worked well. The end result upon departure from the DynoJet was 164HP. I would have liked to have seen closer to 170 but I will take it for now. Maybe I need to visit Mr. Ludwig before the season starts.
:D
I am the poster child for getting screwy results from dynos. I had a dyno operator swear I was running 18:1 air fuel. As Joe told me at the time, I'd have had holes in the piston if that were the case. What actually happened was the guy had a bad sniffer.
Find a good solid dyno that returns semi-repeatable results and stick with it. Dyno shopping just leads to trouble.
I've seen anywhere from 130 to 165 whp on my car. 160 has been repeatedable on one particular dyno and seems to be correct. Same with torque. Anywhere from 180 to 205.
Look for the repeatable stuff and work with THAT guy.
Quote:
I am the poster child for getting screwy results from dynos. I had a dyno operator swear I was running 18:1 air fuel. As Joe told me at the time, I'd have had holes in the piston if that were the case. What actually happened was the guy had a bad sniffer.
Find a good solid dyno that returns semi-repeatable results and stick with it. Dyno shopping just leads to trouble.
I've seen anywhere from 130 to 165 whp on my car. 160 has been repeatedable on one particular dyno and seems to be correct. Same with torque. Anywhere from 180 to 205.
Look for the repeatable stuff and work with THAT guy. [/b]
What actually happened was the guy had a bad sniffer.
If your refering to the a/f sniffer they stick in the tail pipe, I learned the hard way they are not they way to go. My engine builder will not accept any numbers from them. He uses the O2 port just behing the header with a broadband O2 on his dyno.
Quote:
What actually happened was the guy had a bad sniffer.
If your refering to the a/f sniffer they stick in the tail pipe, I learned the hard way they are not they way to go. My engine builder will not accept any numbers from them. He uses the O2 port just behing the header with a broadband O2 on his dyno.
[/b]
Wives tale.
Quote:
Wives tale.
[/b]
Chris, I certaintly won't argue with you! :D But honestly back to back there was a big difference between the two on my car. The tailpipe sniffer was reading much leaner than the broadband O2 sensor. Could this have been the operator? One was on a dyno jet the other was on my engine builders Mustang.
Dan, exhaust leak maybe? Or I guess that would richen things up?
I'm sure it's dependent on a lot of factors - operator, tailpipe arrangement, sniffer arrangement, etc. The sniffer fell off my car during one pull. I don't trust them.
Quote:
Dan, exhaust leak maybe? Or I guess that would richen things up? [/b]
Jeff, if I would have had a exhaust on the dyno jet it would have been leaking on the Mustang too. The exhaust was not leaking.
Marty, your right there may be other factors and I'm not nearly technical enough to tell Chris or Chuck their business :D . I guess it comes down to how and who reads it. What the hell do I know, I'm only the driver. B)
Theoretically there is no difference in what the sensor will see at the tailpipe versus the exhaust port as far as a/f ratio is concerned. There are factors that influence what that sensor sees. An exhaust leak is the big one and if a cat is in place that will obviously skew the results greatly. Exhaust leaks will generally show up as a leaner than actual reading. The sensor has to be in the tailpipe and not hanging half way out. And the sensor needs to be in good condition. Seems like everyone is using the Bosch sensors now and they are notorious for short life spans when they're exposed to leaded race fuel. They'll begin responding slowly and eventually default to a lean reading. If you are suspicious of the readings you are getting that Bosch sensor is the first place to look. For those of you that want to run a wideband in the car full time and run leaded fuel spend the extra money on an NTK sensor and the hardware to run it.
Again, in a theoretical sense, where using a tailpipe mounted sensor becomes an issue is in the delay of the reading and how that reading is logged versus actual engine RPM. It's possible to have a lean condition at 2500 rpm but depending on how quickly the engine is accelerating, exhaust velocity, exhaust length, etc the hardware might be seeing that lean condition at 3000 rpm and logging it as such.
It also sounds like there is some confusion about the hardware that is used for each location. The tailpipe "sniffers" should be the same hardware that would otherwise be installed closer to the exhaust port. Just with the sensor installed in the piece that bolts to the tailpipe or held up by a floor stand. For the purpose of this arguement there is no difference. A wideband is a wideband.
I've done several sessions at Automotion using my wideband installed in the header or downpipe and compared my results to their setup simultaneously installed in the tailpipe and havn't noted anything outside of an acceptable "noise" range. A ratio difference of around 2/10. Your results may vary. And I can see how it would be hard to trust someone until you've done multiple sessions with them and proven out their methods and equipment.
One of the other local dynos is notorious for giving poor results from failed sensors and problematic inductive rev pickups.