what's the different in weather. The end of the last year could have been cooler air, right now we are in the middle of a hot summer, and that makes a huge difference in mph. The hotter the air, the more timing the EEC pulls out. Also warmer air makes less power.


Brian

 

what was the weather conditions last year.......barometer, temp, relative humidy.........compared to this year.......if you aren't within reason than there's no real comparison. I would say it's tune related due to weather.

Here's some info.

Added hooiser qtp's and lost apprx 2mph throught he traps.

Added ported blower and my mph with the qtp's ......running in the heat......is where my best mph on my f1's was.

 

I gained 3.5 mph just by going from 26" MT ET Streets to Hossier 28"

Suavy

 

Also, the load is different on the dyno. There's a few tables that pull timing and one is load related. When you are tearing down the track with slicks, your truck will have a different load and may pull more timing than on the dyno. The best way to test timing is to either check realtime going down the track or even better yet and safer, is to datalog and check it out after the run.

Perfect example, I had my timing dead on at 18 degree's on the dyno. Went to the track and saw 12 degree's through the full pass. We played around with the tune a little and I picked up 6mph.

 

I thought if you cut better 60' times you are effectively extending the length of the track so you should trap higher. Consequently the worse off your 60's are the less track you have to get up to speed.

 

the more you spin the worse et.......better mph,
the less you spin, the better run at the traps.......so lower et....less mph

 

So what is my "real" timing since I saw 18 degrees on the hot dyno at WFC?

 

You wont know unless you datalog it.

I ran on the same dyno that same day, except it was earlier in the morning. My #'s in my sig are from that morning. I made more HP on the first pull with a leaner tune, but the truck's dialed in now at a perfect 12:1 A/F.

I put the temp/humidity #'s into a calculator, and also looked up humidity effects on HP.

In cooler weather, the humidity doesnt actually hurt your #'s, it may help, as it almost acts as a "cooling" medium, cooling the charge in the combustion chamber as the water molecules quench the heat somewhat.

From all my HP readings, it appears the the myth that higher humidity is worse is not a true statement.

 

that's how much you saw on the first pull. Once aircharge temps exceed 150 degrees the EEC will pull back to 16 or 15 degrees. If you approach 200 degrees, you can be as low as 14-13. It's not somthing you want to change.

Brian

 

Ok, got it. Find my tuner yet???

 

You can use my Predator if you want... sorry had to do it...

 

Are you running a stock trans? Your problems could be due to transmission slip. Greg talks about this a lot...

--Steele

 

Funny that it would start at the exact same time I reinstalled the blower though

 

Well, I thought it would be a good suggestion since you stated in your post that you were comparing trap speeds between runs you did at the end of last year to the runs you did last weekend. That’s 6 months of additional wear and tear on your intermediate clutch, no? Or did you keep it in the garage the whole time?

Again, it was just a suggestion -- you don't have to roll your eyes at me for trying to be helpfull.

--Steele

 

He's awfully hostile for a person who is always asking for help


...although it's often hard to express emotion with a limited amount of smileys - heh