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Embarrassingly Low Dyno Results. Terrible Rear End Whine


FomocoUT

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Yeah, that's much more telling. Always good to have a baseline to compare it to. Have you done ANYTHING to your car? CAI, pulley swap, different caps, hood struts even? If so, you may NEED a tune adjustment as it would seem your car may be pulling timing above 5k. If not, your car may be sensing something not obvious, or obvious to a good mod shop.

 

If the rear end noise gets fixed, I would give one more dyno run to make sure that doesn't fix it. If it doesn't, perhaps a call to SVT is in order with documentation at the ready. It may actually come down to tune adjustment by Shelby or a good mod shop to track down your power issue. It could be a number of things though, and once you start changing the stock tune, you likely let Ford off the hook if it ends up being mechanical.

 

That said, i don't trust Ford yahoos at dealerships. One SVT tech looked at my gt350 then with the hood open asked if it was supercharged. (The whipple tends to give it away, yes). So my advice is this- after 6 years and three Shelby's -

 

Forget Ford dealers, find a good mod shop with great attention to detail, respect of customer cars, and not willing to let you blow up your car. Not Shelby, someone local. You cannot take your car to Shelby and get in and out service, and its just not practical for little things and breakdowns. Big jobs, sure, but not your usual thing unless you are within 150 miles.

 

Once you have a good mod shop, have them look at any problems you have first, let them determine if it should be covered by ford, or a tsb, so you can be informed and armed with all the details ahead of time if you do need warranty dealer work. In my city, there are almost zero dealers that will do warranty work on SVT vehicles.

 

Lastly- get a really good tuner. I suggest Jon Lund. Hard to reach, yes, but the best there is. When my GT350 had a faulty cam sensor, Shelby called Ford Racing. (It was the 624 ford racing tune). When Ford Racing couldn't figure it out, they punted to Jon. It took him 15 minutes. Even though at the moment i hadn't modded the 350, my relationship with Lund Racing and my local mod shop saved my ass.

 

 

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If the car is stock and you are having problems never add a tune it will void your warranty. I would call SVT about the low horsepower and give them the dyno numbers and all the info like the horsepower flat lining at 5000 RPM's and above. Also if the other GT500 was stock and made 80 more horsepower on the same Dyno tell SVT about that. There are some dealers that have people that know what they are doing you just have to find one. I'm lucky I have a dealership who has great guys to work with.

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"Properly tune the car" is a modification. A modification that will almost certainly void a Ford factory drivetrain warranty.

Well, without coming across negatively towards Shelby here, let me just say that Ford needs to be the one to address his problems first. Shelby doesnt do Ford warranty work, so he would have to pay Shelby to diagnose the problem, and then take it to Ford anyway. A simple tune voids the powertrain warranty, whether done by Shelby or not, and even though Shelby may carry supplemental warranty for some things done by SA or the performance shop, I dont think the OP wants to really have to wrestle with taking his car BACK to SA again if the problem isnt found, and then dealing with, its not our problem its Ford's and Ford saying its not their problem anymore cuz Shelby did work on the car...its a nightmare scenario dude. And one I am EXTREMELY familiar with. I had my first taste of this with my GT350. I had 220 miles on my brand new car direct from Shelby before I had to take it in to Ford. Guess which one took care of the repair- yup, ME. It was a bad wiring harness from day one, and apparently, all my fault.

 

Your suggestion makes perfect sense in a perfect world. Taking your Shelby to Shelby seems like a no brainer, but it is not the way to get the OP's car fixed under warranty if that is his intention.

 

 

It's your suggestions that make the most sense in the perfect world - Please read perteninent owners post or the foillowing from his post: "Well, I took the car to the dealer. It didn't take three blocks before the Service Manager said "let's replace the ring and pinion".

 

Okay, now about the power. So I am told that Ford dealers have no way to act upon an issue such as this. They can check to see if there are any updates for the software, but they cannot do much more than that.

 

Further, I was told that there is no expressed warranty about the horsepower, so there is nothing that they can do about it. He told me to take it to an aftermarket tuner. Great".

 

Properly tuning the car means making sure the car is tuned within the correct factory parameters. Performance tuning involves modifications.

 

The owners comments and your subsequent post validate my suggestions.

 

Nice jousting with you without a lot of hate and discontent which unfortunately seems to not be the case with a lot of forums, which drives folks with a lot of knowledge and expertise away. All of your points including those in your last post are well taken and very valid. I think however, that it is questionable that the dealer would advise the owner to take the car to an aftermarket tuner for performance tuning, since the car is still in warranty. Then Ford could void the warranty, and that's the end of Ford's warranty responsibility for the car. That is almost funny, certainly not to the owner. But I would think that suggestion through and get it in writing. Other than replacing the ring and pinion, sounds like the dealership isn't going to offer much. If the car was optioned with the performance package as the owner stated ("SVTPP"), it should have come with the Torsen, not a stock rearend as the owner stated. Something sounds funny here.The Torsen is generally indestructible.

 

Happy trails

 

mrdoc442

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Thanks, no jousting intended tho. For me, I felt some clarification seemed appropriate. As an event organizer, and regional director, I have heard every experience ranging the spectrum of great to nightmare. A previous post stated how great their experiences are with their dealer, and that is the case for many owners. That said, if even 50% chance at getting a bad experience from a dealer is there, (and from the experiences shared with me it is much higher than that), compounded with the trouble the OP stated initially with his dealer, is why I suggested what I did.

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is it running out of fuel @ 5k and above? might have a bad pump or a blockage in the line..

OK so they cannot address the dyno numbers, they can address the flat line over 5000 RPM. See what happens with the ring and pinion, if that does not fix it, call SVT, period. Don't take it to any modification shop unless the initial problem is fixed. If you put in a new tune and find other problems, IE a bad pump, you could get stuck with the bill and voiding warranty
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Just a note....I was able to compare the dyno results with the other Utah GT500 that ran on this very same dyno with a 530HP result. Our horsepower curves are IDENTICAL until 5000RPM, where mine goes flatline. The other GT500 goes on to 530HP at 6500RPM. Any comments?

 

I will wait for the new ring and pinion. After I get a few miles on it, we will run the dyno again.

 

 

Mine was the other GT500. My car is completely stock except for an Airaid filter and a Ford resonator delete, neither of which give a HP increase. I would recommend getting the diff fixed then running it on a Dynojet. There are a lot more cars run on a Dynojet so you will have a lot more data to compare your power to. Mustang dynos are too variable for a good comparison, in my opinion.

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Thanks, no jousting intended tho. For me, I felt some clarification seemed appropriate. As an event organizer, and regional director, I have heard every experience ranging the spectrum of great to nightmare. A previous post stated how great their experiences are with their dealer, and that is the case for many owners. That said, if even 50% chance at getting a bad experience from a dealer is there, (and from the experiences shared with me it is much higher than that), compounded with the trouble the OP stated initially with his dealer, is why I suggested what I did.

 

 

I think our intent is the same, honest straight forward discourse, sharing our expertise, setting a good example without a lot of hate and venom, with whatever is best for this forum and it's members our goal. You are dead nuts spot on regarding a lot of dealers and owners experiences. A person need look no further than the SVT program with the dealerships. I don't profess to know everything about the SVT program, but I do know this. One of the things a dealership has to do to qualify for being an SVT Dealership is send at least one mechanic/technician person, maybe more at larger dealerships, to training for SVT put on by Ford, I would think at least annually. After attending some short Ford SVT training, that person is now the SVT expert for the Dealership, In many small Ford SVT rated dealerships, that dealership may qualify for one Shelby GT500 per year, and maybe some SVT Raptors or Focus's or other more common SVT vehicles. That SVT trained mechanic/technician may or may not ever work on that one Shelby GT500 the dealership sold if it was from another area some distance away. This process lends itself to what I would term SVT expertise issues at a lot of dealerships. Even with the Ford SVT training, it does not guarantee a high level of competence with these highly sophisticated and rarely if ever again seen at some dealerships, GT500 vehicles, thus limiting the opportunity to gain hands on experience actually working on this SVT vehicle. The reason I know about the requirement I mentioned above about qualifying is because one dealership here in Montana I was considering buying a 2013 Shelby GT500 from actually told me that I could buy the car for MSRP, with no dealership mark up, except for paying for whever it cost them to send their tech to SVT school tacked on to the MSRP. I forget exactly how much it was, but it was one or two thousand dollars. I didn't buy the car from them. My purpose in mentioning all of this is to point out at least one reason some dealerships offer crappy SVT service, especially on the GT500 cars, which compared to the other SVT vehicles, are relatively far and few between. If the factory "SVT trained" tech is out the day your GT500 happens to be scheduled, some regular line mechanic or tech may get the assignment to work on your Shelby GT500. That being said, it might not be a bad idea to find out who has been SVT trained in your dealership, and request or better yet demand that they and only they work on your vehicle. With this system that is probably the action that makes the most sense, and even that doesn't guarantee success. Hopefully most reputable dealerships steer the SVT vehicles to the properly trained mechanics/techs.

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  • 2 weeks later...

Not to add to frusteration but mine dynoed 621 RWHP and 631 stock ft TQ. So I thought if I added the 15%ATI and monblade ford racing TB I would see a nice increase. I think I saw maybe 20 hp. I dont claim to know a lot about cars but if your rearend sounds like you say that deff could hurt hp numbers. Please let us know when you get this fixed!

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Not to add to frusteration but mine dynoed 621 RWHP and 631 stock ft TQ. So I thought if I added the 15%ATI and monblade ford racing TB I would see a nice increase. I think I saw maybe 20 hp. I dont claim to know a lot about cars but if your rearend sounds like you say that deff could hurt hp numbers. Please let us know when you get this fixed!

Dynojet or Mustang dyno?

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  • 7 months later...

First of all, I must apologize for not reporting back sooner. It has been six months since my local dealer ordered a new ring and pinion for my car. at the same time that the ring and pinion was replaced, I also had the oil changed. By that time, the mileage was at about 1000.

 

Replacing the ring and pinion made an immediate difference. The car was much quieter, and it felt like it had more power. I do not drive this car much, and given that I wanted to run it on the exact same dyno, I never reported the improvement on this site until I had the numbers.

 

Well, on Friday, February 21, 2014, I finally had a chance to run the car on the same Mustang Products dyno. As I mentioned, in May of 2013 I did two dyno pulls with my 2013 GT500. When I look back to my original post, I see that I had made a typo that I had not noticed until today. Back then, I posted that my GT500 had pulls resulting in 480RWHP@6500rpm in the first run and 455RWHP@6000rpm in the second. The actual numbers back then were 460RWHP@6500rpm in the first run and 455RWHP@6000rpm in the second. DIsmal for this car at best, and what prompted me to post my problem on this site.

 

With approximately 1200 miles on the car, and with the new ring and pinon, I did three pulls on Friday. The results were amazingly improved:

 

1st pull: 523RWHP@6000rpm

2nd pull: 521RWHP@6000rpm

3rd pull: 518RWHP@6000rpm

 

Close to 70HP improvement over the results from May. The dyno operator had the old record on his file. He was astounded.

 

Needles to say, I am much happier. These pulls were done in 3rd gear, which resulted in about 130mph. The car leaped to redline in each pull, it was incredible. I am certain that when I measure it again at 5000 miles, it will be even slightly better.

 

Again, I apologize for not reporting back sooner. I an mot sure if anyone will even come back to read this, but I did want to post it for those few. If you are experiencing low HP numbers or a loud whine in your differential, here is good evidence for you to take to your dealer for consideration. Thanks to all who give their time and opinions.

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You've solved your problem... 3rd gear is not 1:1. It's most likely 4th although my Roush charged 2012 5.0 was 5th. I had the same issue when dnyo my 2012... they (dynajet) will know right away when they see how low your mph was.

 

Call SVT or Dynojet to confirm. Be sure of the correct answer and have proof as your dyno shop won't want to admit to their mistake... Your WHP will jump 60-70 HP when they run in the right gear.

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You've solved your problem... 3rd gear is not 1:1. It's most likely 4th although my Roush charged 2012 5.0 was 5th. I had the same issue when dnyo my 2012... they (dynajet) will know right away when they see how low your mph was.

 

Call SVT or Dynojet to confirm. Be sure of the correct answer and have proof as your dyno shop won't want to admit to their mistake... Your WHP will jump 60-70 HP when they run in the right gear.

From the SVT Specs on the 13-14 GT500 - 4th is 1:1

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If you are running out of fuel over 5000 Rpm's, you may have a clogged Fuel Filter. Ck that, run it in 4th gear on a Dynojet, set on SAE, Smoothing 5....What Octane fuel are you running, 91??? Good luck and let us know. I hope to get mine on the Rollers this Spring....

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Gees people, we need to go over some facts real quick. HE OBVIOUSLY FOUND THE PROBLEM. stop suggesting other things. if a 70 horsepower gain doesnt prove that i dont know what does.

 

DYNO LESSON: the reason for the dyno in the 1:1 gear ratio is due to the Dynojet. Dynojet mathematically creates a horsepower number based on mass (which is the known weight of the rollers) and accleration (how fast the car is accelerating the known weight).

F=ma

From force (F), we can calculate horsepower.

Dyno the car in 2nd gear instead of third, and acceleration (a) goes way up, causing force (F) to go way up. (aka going up a gear would cause him to LOSE power)

So by dynoing the car in the gear closest to the 1:1 gear ratio, we eliminate any acceleration advantage or disadvantage caused by the transmission, which gives us unskewed whp numbers (even though Dynojet has a fudge factor in there which makes them skewed anyways and read high).

As for other dynos out there (i.e. Mustang and Dyno Dynamics) - they use a load cell to measure roll force (the amount of force the tireicon1.png is placing on the roller). Based on roll force and the radius arm going to the load cell, we get roll torque. Based on roll torque and roll speed, we can get vehicle horsepower. Vehicle horsepower and vehicle RPM gives vehicle torque. It doesn't matter what gear you run in on load cell style dynos as they are measuring force, not acceleration. Force does not change from gear to gear.

 

essentially using the higher gear on a mustang dyno is only to get a better idea of how the power curve looks.

 

 

CONCLUSION: Every dyno reads different. he said that another 2013 did 530 on that dyno and someone else who posted in this thread said he used the EXACT SAME dyno and made 530. Am i the only one that it is apparent to that that is just how this dyno reads? A dyno is a tool of measurement and can read different than others. just like a scale, some may read different, but you get the general idea youre looking for. In all reality a dyno is for tuning and constantly checking the power / torque curve and measuring results, not just a dick measuring contest, if you want to do that take it to the track where it actually counts.

 

I do think that the OP should go to that dyno shop around the corner previously mentioned by the other gt500 owner who got 530 on the mustang dyno.

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530 on a 662 SAE cert car?? 20% drivetrain loss?? The numbers DO mean something much more than dick measuring. You may be able to find a scale to say your 170lb but that don't mean your not a fat-ass if you actually weigh 270 (sorry no offense intended to the larger guys on the forum) . :)

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CONCLUSION: Every dyno reads different. he said that another 2013 did 530 on that dyno and someone else who posted in this thread said he used the EXACT SAME dyno and made 530. Am i the only one that it is apparent to that that is just how this dyno reads? A dyno is a tool of measurement and can read different than others. just like a scale, some may read different, but you get the general idea youre looking for. In all reality a dyno is for tuning and constantly checking the power / torque curve and measuring results, not just a dick measuring contest, if you want to do that take it to the track where it actually counts.

 

I do think that the OP should go to that dyno shop around the corner previously mentioned by the other gt500 owner who got 530 on the mustang dyno.

+1000

 

I must admit I get a kick out of those who are so concerned about the dyno results of their cars for the purpose of measuring HP. You could dyno the car on 10 different machines and get 10 different results. Could not agree more with the statement above. Dyno tuning is mainly to TUNE the car properly. Anything more than that is just for bragging and peacocking. I don't care how much HP my car has..... it's damn fast and that is all that matters. I care that the power band is correct with no dead spots and the car is not running too rich or too lean. HP is only good to the extent you know how to utilize it and your car can put it to the ground.

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And I love how "You could dyno the car on 10 different machines and get 10 different results" keeps getting thrown around.

 

That's like saying you can weigh yourself on 10 different scales and get 10 different results. While this is true, this does not mean finding the scale with the highest / lowest results makes you actually somehow weigh 20lb more or less than you actually weigh...An inch is an inch. A pound is a pound. A watt is a watt and a horsepower is a horsepower. These are clearly defined engineering units. When you locate a known properly calibrated scale you will get an accurate reading within the known tolerance levels. Yes there will be a variance .0?? +- between machines but NOT 20-30%... Like ANY measuring tool it must be calibrated properly from time to time by qualified professionals with the proper simulators.

 

I'm thinking a majority of owners bought the 2013 GT500 because it was rated 662HP. Would it be ok if it was actually 571HP at the crank?? Oh well, 662, 600, 562 it's all the same right???

 

What I'm saying is blowing of the OP concerns is near sighted. Bottom line if you get 530WHP with a 662 SAE certified motor on a known properly calibrated dynamometer you car is underperforming and you have every right to be concerned enough to investigate (drivetrain loss??) it, I would...

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I'm not disagreeing with you. I place far more emphasis on tuning the car properly which in turn will create the proper amount of HP (the actual number at that point being irrelevant to me). At the end of the day, that will uncover/solve the issue in most cases.

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