Since you were seeking low/ real numbers, you got them. Get that thing tuned correctly, don't worry about the numbers, and go to the track to see what your really have. I dont care if the dyno said I had 200 hp if I can put down low 12's high 11's at the track.

 

what fuel are you using?

if you want real world numbers you should get a g-tec meter, would of saved a lot of time running around to thier facility

 

ya mustang numbers are very low compared to dynojets.

will renntech let you send them your ecu with a copy of the wideband readings to retweak your calibration?

 

Steve,

Heres the data I had from my completely stock Mustang dyno runs. NOTE: The dyno was being run in AWD mode, so both roller sets were connected.

As you can see my numbers were 249 HP and 252 Torque.

Going by these numbers for adding back in the 18% and 12%...

18% ... 82 * 1.2195 = 99.999
12% ... 88 * 1.1364 = 100.0032

18 + 12 = 30% ... 70 * 1.4286 = 100.002

Add back in the 18% drive train loss they told you to use...

249 * 1.2195 = ~303.66 HP
252 * 1.2195 = ~307.30 torque

IF the Mustang dynos typically show another 12% lower than say dynojets, then we add back in the 12%...

303.66 * 1.1364 = ~345.08 for HP
307.30 * 1.1364 = ~349.22 for torque

This looks VERY close to the numbers we had figured for the SRT6 (not advertised, but actually closer to the SLK 32 AMG)

Adding both percentages together and then doing just one step...

249 * 1.4286 = ~355.72 for HP
252 * 1.4286 = ~360.01 for torque

There IS a flaw in these calculations. My question is which is right...
Add in each percentage separately OR add the percentages together and then add back in the overall percentage???

By the way Adding 18% back in... is not the same as subtracting it! Because you are working with LESS than 100% for a starting number, you have to actually add in a higher percentage of the number to get a full 18% of the original 100%.

So, if you LOOSE 18% from say 330 from the drive line, you are loosing an actual 18%. 330 * 0.82 = 270.6 ... BUT, if you want to add back in this loss, you must add in MORE than 18% of 270.6!

270.6 * 1.2195 (21.95% added) = 329.9967

Make sense?

 

I HAVE JUST ONE QUESTION!
WHAT IS THE CORRECT RWHP OF ONE OF THESE CARS WITH INTAKE, EXHAUST, 185 PULLEY ETC.?
DOES ANYONE ACTUALLY KNOW?
Mike

 

I'm going to call them this afternoon and ask them how good their service after the sell is . I don't know if it will do me any good or not, but it's worth a try. I think they have a shop in Springfield Ill., it would be nice to take it over there and have them do a live tune on it. But I'm sure it would cost an arm & a leg.

I run Sunoco 94 octane in it & I do have a new RR G-tech that shows I'm 259 at the wheels during a 1/4 mile run. But I have never done a dyno run on the G-tech, there is a certain way you are suppose to do it. And the manual basiclly say's you about need a manual tranny, it's tuff to do it correctlly with an auto-tranny by the way I read it.

 

They did tell me at that shop not to be suprized if there was a 21% to 23% drive train loss.

 

for the gtec to read properly you have to launch without spinning the tires, once the tires light up the gtec results go out the window

 

A "locker" (a.k.a Detroit locker) goes in the rear end. If you are referring to a lock up converter, these cars are equipped with one.

 

We do all our runs on a mustang to allow for a full pull. 25 percent is a good number to use for flywheel hp. That should net you around 400, which is decent for your mods. We pulled 208 on a mustang, which is about 267 flywheel with a manual. Just use it as a base line for continued testing, or go to a dynojet and feel really good about the numbers.

 

I know that's correct, that's one reason I alway's launch with the TC on. I have made a couple runs with the TC off with a lot of spinning and the results were mid 11's in the high 120's. I knew that couldn't be right, but it is very consistant with the TC on. I've also had it fault out because of the TC kicking in so bad.

 

they still have a higher parasitic loss than a manual ... most ranging from 20% to 30% ...

 

Steve,

After peering over your charts, I think you are falling victim to our collective enemy - HEAT.

The numbers a off a bit, but it's not as bad as i believe you think.

Even with the dyno fan, it is very difficult to replicate real-world airflow.

Your bigger pulley is already straining the limits of the OEM heat exchanger....time for bigger.

The car is definitely pulling some timing and dumping fuel top-end.....how much? Only datalogging will tell.

A bigger HE + a bit of tweaking to your tune should net great results, IMO.

 

If it's the heat, it must have built up fast. Because I had my I/C pump running the whole time and before each pull I looked at the I/C coolant gauge and it was in the 80's.
Although I was very disappointed with the results of the run, I got an A+ on the looks of the car. At the shop everybody had to come look at it, a couple of the guy's just couldn't believe it had an AMG engine in it. And on the way down there traffic in one of the towns I went through got stopped for a line of cars for a funeral. I wasn't looking at the cars going by me much, but when I did look everybody was looking at my car. I got one "sweet" three "wows" and countless jaw drops .

 

Steve,

Have you gone back to a dealer for some work and they perhaps re-flashed your ecu?

I'm surprised you did not get to 6000 rpm. I though Renntech took off the speed limiter or at least set it to 6250rpm.

 

The fastest cars will always be automatics. Anytime you see anything that is crazy fast (like 9's or less in the 1/4) it's almost always an automatic. It's not as fun driving an automatic but it is fun to beat someone in a race while holding my starbucks in the other hand

When I had my GTO I raced a guy with all the same mods except he had a 6 speed and I had an Auto. Here is a video of that race...(i'm on the left with the tint)

http://media.putfile.com/GTOByron

BTW steve,

Just hit the track and I'm sure you will be happy. The dyno is good for things like finding A/F and thats about it....

 

Dyno numbers are great for one thing: comparing before/afters on the same car with the same dyno while adding modifications or doing other tweaks to affect the tune of the engine. Trying to compare Car A/Dyno #1 numbers with Car B/Dyno #2 is almost meaningless. One of the tuner magazines did a great article on this a few years where they took the same vehicle to 7 different dynos on the same day. Not only did they get 7 different numbers, but the difference from hi to low was 54HP!!

Lap times and 1/4 mile ETs with trap speed are a much better indicator of real performance. Nobody ever lost a drag race only to respond "oh yeah, well my car pulled 12HP more than yours on a dyno, so there!" At least, nobody who's taken seriously.

 

It's only been to a dealership two times, once for a 4 wheel alignment and once for an oil change. I have told the service manager not to do anything with the ECU because it had been modified.
As far as not going to 6,000 RPM's, I think the dyno guy will only run the machine up to 100 mph.
I just spoke with RENNtech and they said 266rwhp on that type of machine is pretty good and that if I went to a dyno jet I would probably pull in the mid to high 300's. I believe he said around 370rwhp, he even looked up some dyno jets in my area for me and gave me their phone #'s. They also said to figure at least a 20% drive train loss.

 

BTW what mods are on your NA xfire to get those kinda numbers?

 

So, based on the dyno sheet that looks like mine, with JUST a 20% loss from the drive line, you would have these numbers vs. my stock dyno sheet...

264.9 * 1.25 = 331.125 HP ------------vs. stock----------- 249 * 1.25 = 311.25 HP
294.7 * 1.25 = 368.375 torque --------vs. stock---------- 252 * 1.25 = 315 torque

And that's not even counting the low numbers for the Mustang dyno.

If you factor in the extra 12% for the Mustang dyno loss/low numbers you get

264.9 * 1.470588 = 389.5588 HP ------------vs. stock----------- 249 * 1.470588 = 366.1765 HP
294.7 * 1.470588 = 433.3824 torque --------vs. stock---------- 252 * 1.470588 = 370.5882 torque

So it looks like you aren't getting that bad of numbers after all.