Low Power? Driveability issues.
07-30-2012, 01:06 AM
#1
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Low Power? Driveability issues. Am I crazy or is my car supposed to be making over 300RWHP stock?
I was surprised when I recently installed a 224R cam along with the other non stock components and had it dyno tuned and saw the results. I can't find the sheet at the moment but the RWHP was around 290 and Tq around 279 peak (and average as it varied very little unlike the HP). AFR about 12.4. These are averages by memory but very close. Close enough for my question I think anyway.
2. Since picking up the car and driving it home (3 hours away) it ran fine on the freeway but has a bit of a rough idle, as if there was a miss, not sure how it should run with the new cam in it. It is difficult for me to tell if the much bigger lift of the cam is causing the rough idle or if it should still be smooth, similar to stock and only sound differently. I assumed the LS tuner should have known. Some things I AM sure about which happened the next day or two after the tune are the traction control not working intermittently and the check engine light coming on and then eventually going off again after a couple days. The engine also either dies when put in to drive when cold or will only keep going by surging if I keep my foot off the brake. Since I had the mechanical work done which of course needed a tune to run well it is difficult for me to determine if it is all computer related or if there is a mechanical component to the issues.
I have also been sometimes able to roast the tires from a stop same as stock and other times it won't even do that, an obvious issue there. Sometimes it will accelerate pretty well at WOT when going at least 20 plus MPH and perhaps even break the tires loose. It seems to run and accelerate smoothly at freeway speeds and sounds pretty good.
I have tried to contact the dyno tuner twice now but not had my messages returned. I hope that will change soon. This is a person suggested to me from here and has done plenty of LS cars so why he did not think it odd to have those power ratings from the Mustang dyno is again confusing to me as I would think he would know what was an appropriate power level for this car stock at least and probably with the cam.
So my questions are of course if the power levels seem low for the car and also if the issues seem to be something related to the tune and also if the computer still has the ability to adapt to conditions like it did when stock or not?
I would do the obvious and just take the car back to these guys but I got stuck and had to have the mechanical work done in the next State where the dyno tuner recommended happened to be close by. The mechanic can't tell me much over the phone and the dyno tuner has yet to return my calls.
Anyone had similar issues or can confirm I should be putting out more power at the rear wheels?
I was surprised when I recently installed a 224R cam along with the other non stock components and had it dyno tuned and saw the results. I can't find the sheet at the moment but the RWHP was around 290 and Tq around 279 peak (and average as it varied very little unlike the HP). AFR about 12.4. These are averages by memory but very close. Close enough for my question I think anyway.
2. Since picking up the car and driving it home (3 hours away) it ran fine on the freeway but has a bit of a rough idle, as if there was a miss, not sure how it should run with the new cam in it. It is difficult for me to tell if the much bigger lift of the cam is causing the rough idle or if it should still be smooth, similar to stock and only sound differently. I assumed the LS tuner should have known. Some things I AM sure about which happened the next day or two after the tune are the traction control not working intermittently and the check engine light coming on and then eventually going off again after a couple days. The engine also either dies when put in to drive when cold or will only keep going by surging if I keep my foot off the brake. Since I had the mechanical work done which of course needed a tune to run well it is difficult for me to determine if it is all computer related or if there is a mechanical component to the issues.
I have also been sometimes able to roast the tires from a stop same as stock and other times it won't even do that, an obvious issue there. Sometimes it will accelerate pretty well at WOT when going at least 20 plus MPH and perhaps even break the tires loose. It seems to run and accelerate smoothly at freeway speeds and sounds pretty good.
I have tried to contact the dyno tuner twice now but not had my messages returned. I hope that will change soon. This is a person suggested to me from here and has done plenty of LS cars so why he did not think it odd to have those power ratings from the Mustang dyno is again confusing to me as I would think he would know what was an appropriate power level for this car stock at least and probably with the cam.
So my questions are of course if the power levels seem low for the car and also if the issues seem to be something related to the tune and also if the computer still has the ability to adapt to conditions like it did when stock or not?
I would do the obvious and just take the car back to these guys but I got stuck and had to have the mechanical work done in the next State where the dyno tuner recommended happened to be close by. The mechanic can't tell me much over the phone and the dyno tuner has yet to return my calls.
Anyone had similar issues or can confirm I should be putting out more power at the rear wheels?
07-30-2012, 02:09 AM
#2
well you do have to remember the stock HP numbers are at the flywheel. A dyno measures rear wheel horse power. So your comparing apples and oranges.
So if you consider a 10% loss through the drivetrain, that means your 300HP is about 270HP at the REAR WHEELS stock. So at 290HP, thats about a 20hp gain over stock. And thats assuming, new... right out of the factory.
The "butt dyno" is somewhat subjective. There are many factors that take into place how the car reacts on the street. When your 'breaking the tires loose' is it at night or when the car is running cooler? Some streets can be a lot more slipery then others... are the tires warm or cold. Punching it from 20mph can have a much different affect then say 30mph, as one may drop into a lower gear then another, they also hit the powerband differently.
So, just getting the tires loose is not a good comparison if the car is running well or not.
So if you consider a 10% loss through the drivetrain, that means your 300HP is about 270HP at the REAR WHEELS stock. So at 290HP, thats about a 20hp gain over stock. And thats assuming, new... right out of the factory.
The "butt dyno" is somewhat subjective. There are many factors that take into place how the car reacts on the street. When your 'breaking the tires loose' is it at night or when the car is running cooler? Some streets can be a lot more slipery then others... are the tires warm or cold. Punching it from 20mph can have a much different affect then say 30mph, as one may drop into a lower gear then another, they also hit the powerband differently.
So, just getting the tires loose is not a good comparison if the car is running well or not.
07-30-2012, 11:25 AM
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Yes basically that was it. Confirming that the power ratings were for the motor and not RWHP. In that case taking in to consideration a 20% loss from the drive train as I have an A4 we estimated the motor was putting out 350Hp which is in line with the advertised gain for the cam. Not putting it on the dyno before I don't know exactly where it was at before.
I understand what you mean about variations but these contrasts are noticeable.
I am just using the "butt dyno" references as a comparison to how it should be running to reflect a 40Hp gain. Not expecting anything huge, just enough to notice, or at least be capable of the same things. Sometimes the issues have been pretty major so there is something wrong, I just don't know what yet. These are the same places that I have driven in the same manner stock for comparison. I would have noticed the difference if this had all been done in one day rather than a month before getting my car back. What is really disappointing is the issues with the motor dying when put in to gear and lack of power at times and the traction control working intermittently only now. If the dyno tuner were to return my calls that would also make me feel better as he should know if this is common and how to fix it.
Really I would really just like it to be running properly. To spend money and have it not run as well as it was is pretty disappointing to be honest. I will be driving back down to the mechanic to fix that seal later this month and at the same time try to get the dyno tuner to figure out whats causing these issues. I would be interested if the computer was still capable of adjusting to conditions as it did before the tune. I need to install some new U joints anyway and may do a higher stall converter at the same time. Of course upgrading the exhaust would be a good idea with the new cam in there. It's just a matter of money.
I understand what you mean about variations but these contrasts are noticeable.
I am just using the "butt dyno" references as a comparison to how it should be running to reflect a 40Hp gain. Not expecting anything huge, just enough to notice, or at least be capable of the same things. Sometimes the issues have been pretty major so there is something wrong, I just don't know what yet. These are the same places that I have driven in the same manner stock for comparison. I would have noticed the difference if this had all been done in one day rather than a month before getting my car back. What is really disappointing is the issues with the motor dying when put in to gear and lack of power at times and the traction control working intermittently only now. If the dyno tuner were to return my calls that would also make me feel better as he should know if this is common and how to fix it.
Really I would really just like it to be running properly. To spend money and have it not run as well as it was is pretty disappointing to be honest. I will be driving back down to the mechanic to fix that seal later this month and at the same time try to get the dyno tuner to figure out whats causing these issues. I would be interested if the computer was still capable of adjusting to conditions as it did before the tune. I need to install some new U joints anyway and may do a higher stall converter at the same time. Of course upgrading the exhaust would be a good idea with the new cam in there. It's just a matter of money.
07-30-2012, 08:46 PM
#4
TECH Resident
even with an A4 that cam should put you over the 300 mark.. mine is around 340 on the stock long block and cam. i have an M6 but you should still be well over the 300 range...
My mods are on a 2000.. BBK longtubes, ORY, Taylor wires, Ram air, SLP lid, Moroso catback, Air!, egr! and a Street tune.
My mods are on a 2000.. BBK longtubes, ORY, Taylor wires, Ram air, SLP lid, Moroso catback, Air!, egr! and a Street tune.
07-30-2012, 10:30 PM
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Could be even with an A4 that cam should put you over the 300 mark.. mine is around 340 on the stock long block and cam. i have an M6 but you should still be well over the 300 range...
My mods are on a 2000.. BBK longtubes, ORY, Taylor wires, Ram air, SLP lid, Moroso catback, Air!, egr! and a Street tune.
My mods are on a 2000.. BBK longtubes, ORY, Taylor wires, Ram air, SLP lid, Moroso catback, Air!, egr! and a Street tune.
How is your idle compared to stock? Does the motor just have a lope or does the car shake a bit? IOW can you just hear the difference or feel it. I am trying to figure out if this is normal or not. I was really counting on the dyno tuner to make things work properly and squeeze as much power as possible out of this.
It is just not running properly so I don't think it is making maximum power. I also know it will make more when it can breathe better. I hope to get this figured out by taking it back to both the mechanic and tuner. I was in a tough spot with my car and though I trust the mechanic I used he is in Portland and I am in Seattle and the dyno tuner in Vancouver so not really a convenient stop during the week, however that is what I will have to do to fix this...hope none of the new mechanical parts are having issues...just a computer adjustment would be far better. I do need new U joints but still I think that should not generate a big power loss, just perhaps break running really hard on the dyno, but I will be getting those replaced with the best I can find on the trip down there.
Thanks for your info. I hope to get this figured out and have the car running as well as it can. As you can see most of the parts in it are all for increased durability, only the cam for power. This is to help support future mods as long as I had to go deep in the motor.
