1997 stock GTS
Red line = Stock ECU
Blue line = Mopar ECU
Pulls were done 2 hours apart.
Mopar ECU vs Stock ECU
- Thread starter Marv S
- Start date
1997 stock GTS
Red line = Stock ECU
Blue line = Mopar ECU
Pulls were done 2 hours apart.
99 R/T 10
Enthusiast
So, are you saying there was no real gain? Other then the TQ being a little higher from 3200-4700? What were the final numbers, can't read them from the chart.
OP
OP
I cropped out the rwhp numbers because they will cause some confusion - it gives numbers quite different (lower) than a Dyno-jet. The testing was done on a dyno that is not so common. The drum is not a "freewheel" like a Dynojet or Mustang as it loads the wheels to simulate the resistance a vehicle is subject to on the road or track. A demonstration was done in a "freewheel" mode to simulate other dynos and the power lines were much higher above 4,000 rpm than when the roller was loaded.
http://www.dyno-comp.com/tuner.php
It also tracks the A/F ratio in real time during the pull, can plot the boost pressure, egt, pre and post intercooler temps.
What we were looking for were the differences between the stock ECU and MOPAR ECU. It was a cool, damp day and heat soak was not an issue. The stories range from running rich to losing a lot of HP to small gains. The car was dyno run after sitting at about 1.5 to 2 hours before each pull.
I think that if we had run the car with the stock ecu and immediately replaced it with the Mopar ecu the Mopar ecu would have yielded lower numbers due to some heat soak - that's why we waited between the pulls.
Also, the A/F ratio graph was pretty much the same on each of the ECU's.
(Other observations: the stock SRT Vipers are easily more powerful than the Gen 2. The Gen 1 Vipers have some strong torque numbers. An SRT with heads only upgrade was much stronger than an SRT with headers and exhaust only upgrade)
http://www.dyno-comp.com/tuner.php
It also tracks the A/F ratio in real time during the pull, can plot the boost pressure, egt, pre and post intercooler temps.
What we were looking for were the differences between the stock ECU and MOPAR ECU. It was a cool, damp day and heat soak was not an issue. The stories range from running rich to losing a lot of HP to small gains. The car was dyno run after sitting at about 1.5 to 2 hours before each pull.
I think that if we had run the car with the stock ecu and immediately replaced it with the Mopar ecu the Mopar ecu would have yielded lower numbers due to some heat soak - that's why we waited between the pulls.
Also, the A/F ratio graph was pretty much the same on each of the ECU's.
(Other observations: the stock SRT Vipers are easily more powerful than the Gen 2. The Gen 1 Vipers have some strong torque numbers. An SRT with heads only upgrade was much stronger than an SRT with headers and exhaust only upgrade)
rubbersidedown
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"The stories range from running rich to losing a lot of HP to small gains. The car was dyno run after sitting at about 1.5 to 2 hours before each pull.
I think that if we had run the car with the stock ecu and immediately replaced it with the Mopar ecu the Mopar ecu would have yielded lower numbers due to some heat soak - that's why we waited between the pulls."
It is my belief that this is an inaccurate way of measuring- Heat soak can be an issue, you are correct. But, to see what the real results are, you should do a pull at operating temp (coolant, intake, and oil temps), swap ECUs, another pull and swap back and one more pull. This is the only definitive way to see what the real gains are. Most people don't start their cars, then immediately beat on them. Pulls at operating temp are the only way to see real differences. An LS1 vette, for example may test way better with a hypertech programmer when cold. Now, make that pull at operating temp vs. a stock pull at operating temp and you'll very commonly lose power due to the added timing- which turns into knock retard, thus loosing power. Oil temp can skew your readings also as cold oil (room temp) is heavier and takes more power push through. The best readings you can get is from a cool intake and warm oil (dyno tricks...). I always do back to back testing with products- it's real results. Whenever we tune on the dyno, the cars are ALWAYS tuned at a consistent, normal operating temp. If the customer chooses, then we make a "cold" pull at the end.
Just my $.02.
I think that if we had run the car with the stock ecu and immediately replaced it with the Mopar ecu the Mopar ecu would have yielded lower numbers due to some heat soak - that's why we waited between the pulls."
It is my belief that this is an inaccurate way of measuring- Heat soak can be an issue, you are correct. But, to see what the real results are, you should do a pull at operating temp (coolant, intake, and oil temps), swap ECUs, another pull and swap back and one more pull. This is the only definitive way to see what the real gains are. Most people don't start their cars, then immediately beat on them. Pulls at operating temp are the only way to see real differences. An LS1 vette, for example may test way better with a hypertech programmer when cold. Now, make that pull at operating temp vs. a stock pull at operating temp and you'll very commonly lose power due to the added timing- which turns into knock retard, thus loosing power. Oil temp can skew your readings also as cold oil (room temp) is heavier and takes more power push through. The best readings you can get is from a cool intake and warm oil (dyno tricks...). I always do back to back testing with products- it's real results. Whenever we tune on the dyno, the cars are ALWAYS tuned at a consistent, normal operating temp. If the customer chooses, then we make a "cold" pull at the end.
Just my $.02.
OP
OP
The tests were done at normal operating temps. The dyno op. would not even consider letting someone "start their cars, then immediately beat on them"
The car did not just sit on the dyno for 2 hours, cold start and test. It was driven to bring up to temp for each test, to bring the vehicle into the test in the same condition with either ecu. Each ecu also went through a "learning procedure" to learn the full range of the tb's. Not looking for glory hp numbers - just looking to see how the car would be different under same conditions - but with 2 different ecu devices.
Doing a back to back pull with just the time it takes to change out the ecu will allow the big Viper motor to heat soak and the second test will always show less power - even using the same ecu for both tests. Been there-done that.
The car did not just sit on the dyno for 2 hours, cold start and test. It was driven to bring up to temp for each test, to bring the vehicle into the test in the same condition with either ecu. Each ecu also went through a "learning procedure" to learn the full range of the tb's. Not looking for glory hp numbers - just looking to see how the car would be different under same conditions - but with 2 different ecu devices.
Doing a back to back pull with just the time it takes to change out the ecu will allow the big Viper motor to heat soak and the second test will always show less power - even using the same ecu for both tests. Been there-done that.
rubbersidedown
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"Doing a back to back pull with just the time it takes to change out the ecu cause the big Viper motor to heat soak and the second test will always show less power - even using the same ecu for both tests. been there-done that."
Not true- If you keep your IATs consistent on your pulls- Do five pulls and I gaurantee your last three are within 2 HP of each other @ peak. If the never ending heat soak were true, your aluminum manifold would turn into a melted aluminum popcan while you were driving down the road!!!
The PCM has some adaptive stategy for fuel trims, which sometimes require 2-3 pulls to get into the P.E. on the PCM tables. But the T.B. (I'm assuming T.B. means throttle bodies) do not have to be "relearned" as 5v on the TPS is 5v.
Just my $.02
Regardless, I can relate to the gross verdict given- the mopar perf PCMs are not too much above and beyond the stock- most cars benefit more from a Roe VEC-II and dyno time.
It looks like a dyno dynamics dyno graph- you should post #'s just for S&G.
Not true- If you keep your IATs consistent on your pulls- Do five pulls and I gaurantee your last three are within 2 HP of each other @ peak. If the never ending heat soak were true, your aluminum manifold would turn into a melted aluminum popcan while you were driving down the road!!!
The PCM has some adaptive stategy for fuel trims, which sometimes require 2-3 pulls to get into the P.E. on the PCM tables. But the T.B. (I'm assuming T.B. means throttle bodies) do not have to be "relearned" as 5v on the TPS is 5v.
Just my $.02
Regardless, I can relate to the gross verdict given- the mopar perf PCMs are not too much above and beyond the stock- most cars benefit more from a Roe VEC-II and dyno time.
It looks like a dyno dynamics dyno graph- you should post #'s just for S&G.
OP
OP
That's fine. We'll agree to disagree. There are several who have done pulls on these cars while waiting 10 minutes between pulls and have seen power go down every time with the later pulls. Posts to that effect go back to the old board on Car & Driver. Perhaps they did not go to the extent you do to maintain a constant situation.
Similar posts about what to do when putting in a new or reset ecu, include a procedure by Sean, discuss cycling the tb's slowly through the full range of motion a couple of times prior to starting the car after hooking up the new or reset ecu.
This test was done in a method to avoid any such issues - be them valid or not.
End result was nearly identical power lines between the Mopar and stock ECU.
Mopar ECU has a slightly higher idle- even after 200 miles of road time. One item that was not tested on the dyno was the claim of a higher rev limit on the Mopar ECU.
[quote If the never ending heat soak were true, your aluminum manifold would turn into a melted aluminum popcan while you were driving down the road!!!
[/QUOTE]I got one e-mail telling me he was glad to read heat soak didn't cause him to lose power and he can stop buying those ice bags at the strip.
Similar posts about what to do when putting in a new or reset ecu, include a procedure by Sean, discuss cycling the tb's slowly through the full range of motion a couple of times prior to starting the car after hooking up the new or reset ecu.
This test was done in a method to avoid any such issues - be them valid or not.
End result was nearly identical power lines between the Mopar and stock ECU.
Mopar ECU has a slightly higher idle- even after 200 miles of road time. One item that was not tested on the dyno was the claim of a higher rev limit on the Mopar ECU.
[quote If the never ending heat soak were true, your aluminum manifold would turn into a melted aluminum popcan while you were driving down the road!!!
[/QUOTE]I got one e-mail telling me he was glad to read heat soak didn't cause him to lose power and he can stop buying those ice bags at the strip.
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