Interesting.Im guessing the ride height.

 

The 70 pounds off the front probably helped some, but the only logical explanation is the reduced ride-height which greatly improved the aerodynamics at 100+ MPH. And, that is something for everyone with 4th Gen F-Bodies to keep in-mind.

The only other possibility is something crazy happening with the converter.

Not to leave good-enough alone, today I adjusted the front QA-1 coil-overs down to reduce the front-end ride height by another inch (27" front wheel well height).

WD

 

mmm

 

WD did it pick up anymore?

Also how is your alignment set? And what front tires?

I was just going to get the sportsmans for the heavier cars..... But my a-arms are sliding around, I need to weld the washers. I'm going to lower mine some more now

Also are you using a 275 spring?

 

I haven't been to the track after lowering the front another inch (no race this weekend). And next week's race (Big-Bucks out of town) will be 1/8 mile, so I can only evaluate my 60fts and 1/8 mile ET and MPH.

I just had the front end aligned by the local drag race guru (Pro-Mod guy) who has a high-tech alignment shop, so he knows how to set it up correctly. The front tires are Goodyear 26" front-runners,

I can't remember the number on the QA-1 coil-over springs, but they are the softest ones.

My A-Arm adjustments haven't slipped yet (knock-on-wood). I marked them with a silver Sharpie and they are OK after a two-day race.

WD

 

I like to break it down to hp gain. At this level every .1 ET reduction or MPH improvement is worth about 10 hp. You picked up 30 to 40 hp woth of improvement with the additional mph (120 to 123/124).

The near 100 lbs weight reduction is where 10 hp came from.

Mdacton just hit it on the rest of the improvement while you verified it; front end alignment. All of the fast guys align the front end at some optimized setting to avoid scrubing speed. Your buddy didn't get to pro-mod level by overlooking this important detail.

 

I agree a good front end alignment is king however the car did not pick-up ET and its sixty foot did greatly improve or improve at all, with the weight reduction (close to 80 lbs) the moving of the initial mass would have been greater (improving 60'), and the car would have been able to move itself down the track easier (improving both ET and MPH).

There was no mention of this alignment in any previous post but I can see a little ET increase and maybe 2mph.

 

Well who has any alignment specs on one of these?

I did mine and ran 1/16 toe in
5* caster (was told to run as much as possible)
And 0* camber..... but after the a-arms slipped I have - camber now bottoms are pointed in.....

 

This is what snows me. In my experience I have never picked up mph with a simular 60 foot that didn't net me some et gain.

 

I think the caster was set to -.005 (left & right), not sure about the camber.

I hope when I adjusted-down the front-end another inch it didn't mess-up the camber mid-point. What do you think? I can also call David at the alignment shop Monday and see what he thinks.

And, yes. After I installed the new K-member and A-Arms it had to have a complete front-end realignment.

WD

 

I agree, the 3+ MPH gain really doesn’t seem logical with no ET improvement. Again, the DA was at 4000 + and some change, the worst of the year so far and everyone's 60ft times were down a few numbers (hundredths).

However, I have a stack of time slips from two days and everyone is 123 + MPH (except one). Here are some of the actual MPHs; 123.69, 123.40, 123.40, 123.18, 122.98, 123.28.

WD

 

With the DA being so high the MPH is generally the first thing that suffers, that tight convertor still is number one in my book.

 

If the 60fts don't improve at the out-of-town track this coming weekend, I'll do a converter swap. I have another Vig (3200) that I can have re-stalled possibly to 3800, or maybe 4000.

WD

 

is it possible, that the lower ride height and lower weight could help the converter be more efficient at the top end?

do you know if the converter is locking, or is it a locking converter?
I'm in no way an expert but the lack of 60' improvement is puzzling

if you attained the consistency you were looking for why change the converter? unless you want to be faster in class

 

If that were the case then the ET would have improved too.