Analyzing timeslips before and after tune with DA

[ShadyZealot]

So i been doing some thinking. I ran just about the same exact ET on my mail order tune as i did with my real dyno tune. However the DA was alot lower last weekend when i went out on my real tune. Its just not adding up. How significant of a change will the below DA's make. Im starting to wonder if the new tune is hurting me, even though i know it netted a few more HP. I just dont see any other variables. I'm getting confused. I dont know too much when it comes to DA though so maybe im missing something. I just pulled these numbers or drag times.

Any ideas?


Run on mail order tune was

12.19 @ 112.
1.62 60'

Density Altitude: 1223 feet
Elevation:87
Temp:71.6
Pressure:29.89
Humidity:78


Run on new tune

12.21 @ 111
1.63 60

Density Altitude: -438 feet
Elevation:87
Temp:53.6
Pressure:30.1t
Humidity:54

 

[Wes]

Post up your incremental times also to have a fair comparison.

DA makes quite a difference on N/A cars, we deal with it bigtime down here in Louisiana where heat and humidity rule.

Your consistency as a driver also makes a huge difference... launch - which you seem to have down pat, gear change speed (how fast your hands/feet move) and shift RPMs.

Get those incrementals up though to see where the difference lies.

Wes

 

[ShadyZealot]

Good idea. Did notice some of my original numbers i posted were slightly off. Sorry was going off memory.

But here

Old slip______________________ New Slip

60: 1.622 __________ 1.630
330: 4.985__________ 4.990
1/8: 7.769___________ 7.775
MPH: 87.94__________ 88.03
1000: 10.176_________ 10.190
1/4: 12.192___________ 12.217
MPH: 112.05___________ 111.37

Every things seems pretty close to me. Slight differences, but i would of expected the DA to make a bigger difference in my time, even if the tune didnt.

Im shifting every gear right at 6500. Not sure if thats optimal, but for sake of the argument it was consistent. I can post my dyno. It flat lined about 5800, however didnt drop, it held a straight line to 6500.

 

[ArtQ]

That sure looks familiar. I have seen this in my slips multiple times, the DA does play a role, however, I think I have the difference narrowed down to how much RPM you carry out of the 60'. You can get a decent 60 with bog and you can get a decent 60 with some slip or spin. On the new slip you can see where you are a little slower at the 330 and 1/8th. My guess is you didn't carry as much rpm out as you did the first slip.

 

[Wes]

Post your chart up if you don't mind, I'd like to compare/contrast it to some similar combos I've done.

What's your race weight?

Wes

 

[ShadyZealot]

I was just looking over the dyno charts excessive gave me. They gave me 2 of the same print outs. I figured one was before and after. But nope!

Here is the after print out. It made 339 before the tune.

Race weight is right around 3500. I do have a dyno of the old mail order tune, but it was on a different dyno jet and made 348, so i dont know how helpful that would be.

 

[Matt D]

your car is pretty light considering it's a Vert

 

[ShadyZealot]

That weight is with the passanger seat out. Im too poor to afford nice racing seats so i do what i have to lol.

Trunk stripped, 15 inch jegs wheels (which arent really light), and sway bar delete. Besides for that i cant think of anything else i removed. I would take the backseat out but its pointless, in a vert they weight all of 3 lbs.

Im only 150.

 

[ArtQ]

Forgot to ask, did you have the same cool down time in comparison to those 2 runs?

 

[ShadyZealot]

Here is my ohter dyno for what its worth. I know being on different dyno' its like comparing apples to oranges but yeah.

 

[ShadyZealot]

Yeah both of those runs i would say the car was hot. I dont have a temp gauge, but i drove an hour to the track and only let it cool 30 min.

 

[BlownAway05]

Were your tire pressures exactly the same on both runs?

 

[ShadyZealot]

Yep! Right at 20 lbs. Def looks like my 60 was the cause of the slight difference in each run.

Im just at a loss to why the DA wouldnt of played any factor.

Only variable i can think of is the tune.

Looking over the dyno do you guys think that 6500 would be the optimal shift point? Car does have an aluminum flywheel so i was thinking bringing it that high would ensure the rpms stay up for the next gear

 

[Wes]

It's pretty darn close to call - the only thing that is a bit odd about the first sheet is the power seems to be signing off a bit early for the cam. It's tough to say if the power was on its way down or some sorta dip. Knowing what the spark, fueling and airflow was doing there would help answer.

The rest of the charts look inline.

Wes

 

[ShadyZealot]

Yeah i wish they would of gave me the original dyno sheet. Maybe i can get them to email it to me.

 

[Wes]

I think 6500 is a good starting point. Chad will have some input here as well.

Wes

 

[BlownAway05]

How about winds? A nice headwind or tailwind can also have affected your traps. It's hard to make some kind of judgement when only comparing 2 days of runs.

 

[ShadyZealot]

Yeah couldnt tell u what the wind was like on the old run.

New run wind was close to none, if anything the flag was blowing in my favor.

 

[stkjock]

your car is pretty light considering it's a Vert

Damn skippy! mine tips the scales at 3950ish! with me in it!

 

[ShadyZealot]

I can lighten that car up for you if you want, Ill remove that blower for free and take it off your hands. lol