I made my first Dyno run on Saturday. Here's the numbers:

Baro Press : 28.08
Vapor Press : .38
Temperture : 81.7F (1st run) to 83.6F (fourth run)
Gear Ratio : 60.60 RPM/MPH

Max Hp: 295.4
Max Tq: 311.0

Now starts the questions... Keep in mind I am bone stock except for mobil 1 syn. and tinted windows so no real mods to speak of.

(1) The second run netted the 299.8 Hp. The 299.8 came in a spike at the end of the graph. Other runs were in the 295.0 to 295.4 range. On the RPM/HP printout the highest HP number came from the 2nd pass at 296.4 just before the RPM that the spike occured on the graph. I remember clutching early would that account for the spike? Which number should I refer too as my highest output?

(2) I had to drive a pretty good ways to get to the Dyno. Probly 100 miles or better. Had about a 50 min before I made my passes. Would that have affected my numbers much?

(3) I know that it was hot that day and I could have made better numbers in cooler weather but how much better would they have been at say an even 70 deg F?

(4) I am a 6-speed and the guy (Doug at BRA in asheville) told me to make my runs in 3rd gear. I have heard that 4th was the best gear to make your passes in on a dynojet because of the 1:1 ratio. Is there any real differences?

(5) The guy told me to add 20% back to the RWHP numbers to get Crank HP. Does our drive train loose that much power? should I add a different % back to get FWHP?

Also HP/TQ numbers are SAE if it makes any difference. Uncorrected was like 275 hp and 289 ft/lbs or something. So I guess that I can't say that my car is a freak but still I am happy with the numbers. It gives me a good place to start modding from. :p

 

I made a dyno run in 3rd, 4th and 5th and I made 10-15 more hp in 4th than either of the other two (I just pulled that dyno run off my website, maybe I can put it back up tonight for anyone that wants to see it). So, I'm not sure why he said to use 3rd, I have proof that 3rd gear is not the way to go (my run was made as one 3 gear pull on the same dyno, same minute, etc). Just my thoughts....

 

i dont know why he ran 3rd :shrug:, i've always heard 4th cuz of the 1:1.

and 20% drivetrain loss is high, specially for a 6sp. i'd go with around 15%

keep in mind to that the 320+rwhp people qoute out for stock numbers is not the norm. also a dyno is just a number, take it to the track and see what it really does. thats where it counts.

 

I agree. Always dyno in 4th. That would put you at around 310 hp which is about right for a stock car.

 

Yep, dyno in fourth (1:1). Nothing wrong with those numbers at all. They are right on par.

 

I knew it... shucks. I was so hoping to break the 300hp mark. Oh well. I'll know next time.

So how about the spike at the end of the graph. The one that went to 299.8 Hp. Could that have been caused by clutching early??? If so how and why?

 

Nice. Maybe I should have bought an '02.

My '98 is less because the 2002's got an LS6 intake right?

But the '98 has a more agressive cam? So if I get an LS6 cam, it should put out more power than the '02 right?

Plus the '98 has bigger injectors and are running on the rich side, so there should be some more power available with tuning? Thanks.

 

BTW, a Mustang magazine did a back to back dyno test to see the if there's any gain switching to all synthetic. And they found 5 rwhp on a stock Mustang 5.0 with around 80k miles.

The car was not neglected with 5yr old motor oil or anything. They also changed to synthetic for the rearend, power steering, and transmission. But I'm sure that the motor oil accounted for most of the gains.

 

Yeah I know I am not compeletly bone stock but the power gains from synthetic oil at only 8700 miles on the clock is minimal. And I made the pulls in 3rd instead of 4th so the numbers are still a little off the actual mark.

But I really don't understand the spike at the end of the graph. Power was 296.4 @ 5700 rpm then jumped to 299.8 hp then fell to 0 all in about 100 rpms. After the spike the graph plumits to 0 because I shut off at around 5800. I clutched the car early on this run and rpms shot up to around 6000 or 6100. I am wondering if clutching the car too early caused the spike on the HP graph?