Race gas w/ timing advance, no gain. Why?

[TonyG]

I have a blown, intercooled 2v GT. My tuner set it up with 3 tunes:

(1) a pump gas, safe tune (14 degrees, 420 rwhp)

(2) a pump gas/race tune (16 degrees, 440 rwhp)

(3) a 103 race gas tune (20 degrees, 470 rwhp)

Tune #3 was newly acquired. My plans were to use the safe tune on the street. Then when I go to the track, I put race gas in the tank, and switch to the 103 race tune using my Xcal2. BTW, with the 103 race tune, we tried more timing (22 deg), but it didn't help. My tuner thought we were at the limits of the stock heads/cams.

So I ran the 103 race tune back in August (95 degrees, hot humid) and ran 11.60's @ 122 mph. This is clearly a 3+ mph improvement for this type of hot weather (118-119 mph typical with pump gas tunes). So the extra 4 degrees timing seemed to give me 3 mph. Great!

Fast forward to the present.

With my pump tunes in 40 degree November air, I've run 122-124 mph on my old pump gas tunes in the past. So with the race gas tune, I was expecting to hit 125-126 mph.

I was at cecil county the past 2 Saturdays (nice cold 40 degree air), and all I came up with was 122-124 mph traps -just like what I used to run with the pump gas tunes.

Then I did a little experiment:
Using the 103 race tune, I ran 11.556/123.98/1.628. So for fun, I switched over to the pump gas tune (#2). Mind you, I still had race gas in the tank, so the A/F was probably running pig rich. Inexplicably, I ran 11.547/123.36/1.628, which is telling me that I was putting out the same rwhp with that tune.

Any idea what's going on?
Its as if the 103 race tune helped in the hot August air, but not in the cold November air. Could it be that in the cold air, I once again reached the limits of the stock heads/cams as I did on the dyno?

 

[jivepepper]

It's all the same tune? j/k

 

[DBMSTNG]

you'd need to datalog all the runs to properly determine what is going on. it probably has something to do with the timing table used. maybe the race gas ran a more conservative table because of act, ect, or engine temp.

 

[04YELLOWGT]

One thing I've learned by all the tunes I've had on my car is that more timing doesn't always mean more power. I had like 19*-20* timing on my one tune and had the car retuned and the car made like 30-40rwhp more with 17* than it did with 19-20*.


There is no way in hell you've reached the limits of the stock heads and cams though, there is a guy thats making 600+rwhp on a stock heads and cam 2V.

 

[TonyG]

It's all the same tune? j/k

My first thought was that my Xcal-2 wasn't actually loading the tunes that I specified.