I went to Auto-Motion in Louisville KY. yesterday to have my car dyno'ed, a 140 mile drive there. It was not what I would call a state of the art facility, but it wasn't a $hit hole either (down town Louisville is a $hit hole though). I've been down town Louisville before and forgot you about need a co-pilot to get around there. They had been tuning GOAT on one of the dyno's that they had done some engine work on before I got there. I snapped a few pic's of the facility and figured I'd post them first. Then I'll make a second post with of the charts that can't be right except for the A/F ratio's.

 

Okay now for the charts. The people were nice and seemed to know what they were doing, but after the first run I told them there was no way their dyno #'s were right. They said that the Mustang Dynamometer usually give's lower #'s than what people expect. They said when I got home add up my flywheel HP at stock then add up the flywheel HP in mod's, then subtract 18% for drive train loss and the #'s should be close. The place was a nightmare to find in down town Louisville and to make matters worse, I had forgot my wife's camara there. I was just so shocked about the dyno runs I totally spaced it, I was already across the bridge back in Indiana and had to turn around to go back & get it . I've got an email ready to send to them when they open and I can get hold of them on the phone, so I'm just going to copy & paste it in this post. They had also told me I needed to call RENNtech about their tune, I'm really dumping the fuel to it @ top end. They could not do data logs because they didn't have the software to do so.

Hi Cindy, when I got home yesterday I done some number crunching. And I don't think there is any way the numbers were right on the dyno runs. The car didn't even reach what a stock SRT 6 should have by doing calculations of 18% drive train loss. Below are some numbers I came up with, the car "stock" is rated at 330hp at the flywheel and rumor has it it's really 349hp because the MB part of Chrysler didn't want MB people to see it as the 349hp that the more expensive MB was. So I'm being conservative and calling it 330hp in my figures.
Stock = 330 flywheel hp - ( 59.4 = 18% drive train loss) = 270.6 rwhp.
Stock = 330 flywheel hp + 45 flywheel hp for the RENNtech kit ( guaranteed minium) - (67.5 = 18% drive train loss) = 307.5 rwhp.
Stock = 330 flywheel hp + 45 flywheel hp for the RENNtech kit ( guaranteed minium) + V-8 supercharger "Y", intake hose's & K&N filters 15 flywheel hp ( modest estimate) - (70.2hp = 18% drive train loss) = 319.8
My highest run was 266rwhp. I can not get on to the RENNtech company when I myself don't even believe the rwhp numbers are right. I do believe the A/F ratio's, but I can't really get on to them about that because I know they would say if Auto Motions dyno numbers can't be right how can you expect the A/F numbers to be right. You guy's were very nice and good people to work with, but I feel like I wasted a vacation day, $65 for the dyno and $55 in gas to get there and back.

The first pic is a run down of #', 2nd is the 3rd pull - (the probe came out of the exhaust so they just printed out the HP/ TQ). The 3rd pic is of the 1st run and the 4th is of the 2nd run.
BEST RUN A 266 RWHP, I don't think so!

 

Those numbers look right to me, you used a mustang dyno which will read around 12% lower than a dynojet. Multiply your numbers by 1.12 to get close to what you would have made on a dynojet. Mustang dyno's read lower than other dynos do. So your best peak was 297.92 which is good.

Heat and humidity has a big effect on numbers too. Did you let your car cool down an hour or more before you ran on the dyno?

 

Yes, it was cooled down between runs. I had my I/C pump running at all times, I could see the HE temp gauge and it was down in the 80's and it was about 80 degrees down there. I was really disappointed, I expected at the very least of 310 rwhp. I wonder what type of dyno these guy's were on.
2403SRT = 340
Moparrbust = 311 @ 4,800 RPM
srt6_crossfire = 355
Chi-townSRT/6 = 296
NeedsWings = 330 (5 months ago)
waldig = 322 @ 5,500?

 

needswings dyno goes all the way to 6,000rpms.

Some dyno's read a lot higher and some read lower. Altitude, temps and humidity has a lot to do with it as well. I would try to find a dynojet dyno near where you are to do another run. You can go on the dynojet website and they will show you where dyno's are in your area.

Here you go, scroll down and enter your zipcode:

http://www.dynojet.com/dyno_centers/...utomotive.aspx

 

my 296 was on a mustang dyno as well. take her to the track and if she runs low 12's or better you know your car has some monster ballz!

the owner of the dyno I went to told me I could expect around 340-360 on a regular dyno...

 

Thanks mrphotoman, the reason I went with the Mustang Dynamometer is because I wanted real world #'s not inflated #'s. I had read as far as dyno's go it was the most accurate. It probably would have went higher RPM's, but I guess they don't like to run the machine over 100 mph. I also don't think I would have went much higher in HP because @ about 5,100 RPM it started dumping fuel & the HP curve started leveling out.

 

Also remember that you SRT guys drive slushboxes. The drivetrain loss on a slushbox without a locker is higher than a 6MT. I dare say you are losing more than 18%!

 

I hope to get to a track soon. I've been signed up for 2 events and they were both cancelled because of weather. The people at the shop knew I was disappointed, they said don't worry about it, these are just numbers. If your car is fast, it's fast and the numbers don't mean anything. On the way home while on a two lane highway I passed one car with the TC off @ about 60 mph and it chirped the 285's when it shifted down. About 30 miles later I passed another car with the TC off @ about 55 mph and when it kicked down it broke loose and got a little squirelly. I wouldn't think a car that's only putting down 266 rwhp would do that.

 

LMAO, our "slushboxes" are a hell of a lot faster than your big bad ride any day of the week.

"slushboxes" are used by pro-dragsters, they are more consistant, stronger and shift a hell of a lot faster than anyone with a manual transmission ever could.

 

Steve, I agree with Chi, you will find out at the track on the 17th. I am sure you will be in the low 12's.

 

Steve does you car feel fast as it did when you installed the pulley/intake for the first time? No boost leaks or anything(youd hear them if there were plus the car would stumble at idle)?

I have a feeling its just the dyno, and that if my car were on that particular one it would have dynod low too.

Like it was mentioned before if you go to the track and hit low 12's your right on par w/ the rest of us.

 

Woah down and easy there, mrI'mEasilyOffendedman!

An automatic = a slushbox. The basic physics don't lie - automatics have more drivetrain loss inherent in the design than a manual. If that makes you feel small, that's your problem!

 

As bad as I hate to say it. By what the A/F ratio's look like, I could use an ECU tune. The dyno guy said I was probably loosing 10 to 15 rwhp because of the way it started dumping fuel @ around 5,100 RPM. But since he could not do a data log he couldn't say for sure, he said that there could be a reason it was dumping the fuel like that.

 

I've been told time and time again about the # differences between the dynos and I still don't get it. To me, whatever you actually put down at the wheels should be one number only, not different #'s from different dynos with all this percentage bullcrap. Just let us know what the car is really putting down when you mash that pedal to the floor. I'm going to get a baseline dyno on a dynojet on May 24th in Kissimmee, FL. It's good to know what the car is putting down before I start the modding addiction.

 

Oh yeah, it feels as fast as it ever has. At times from a 10 to 15 mph roll with the TC off, I've nailed it and it broke loose - hit the rev-limiter and fell on it's face before it even thought about hitting 2nd gear. Other times doing the same thing, it's smoked the tire's all the way through 1st & 2nd gear before I let off.

 

That's why I went with the Mustang Dynamometer, because it's suppose to be more real world numbers. I just find it hard to believe that my real world number is 266rwhp when the car stock is 330 fwhp and I've added at least 60fwhp to it. The drive train loss at those numbers figure's out at about 32% .

 

Dyno's are a lot like Women

They take your money - You spin your wheels - You end up goin' nowhere - And your heart get's broken

Keep searching until you find one that puts-out what you want!!!

 

Dyno's are great to see what gains you get from your mods and to check your a/f ratios. You can purchase an innovative lc-1 wideband for $199 and check your a/f ratios yourself I have one and it works great.

 

Steve - I think you are just going to have to run it on a track to get a feel for the numbers you are putting down.
All of these dynos are going to give different numbers, then you have to worry about the 5500rpm deal, etc.