Al, the throttle body is exposed to air from around the manifold, no seal. So i will try it with an aircleaner only next time with no scoop, then the scoop and aircleaner to see what all is making power and what is not.

Nice work Greg! once you figure out the best scoop set-up there's gotta be something more in mph. Even at 1.27 the ET is going to suffer this is probably a combo that would like a taller first gear because i'm sure it's spinning down low.

I agree, it might like less low gear although my experience is limited. My only option would be to drop from a 4.56 to a 4.30 that I have on the shelf, but then I take away from the high gear charge a bit?
The 60 foots were all within .002 so I have to wonder if spinning is an issue. I still haven't tried any other shock settings or T.P. I have 30 inch ladder bars, Afco big Guns set at 10 clicks back from full stiff extension, compression at -6 from full stiff. It carries the fronts almost to the 60 ft clocks, wheeliebars are set very high and don't contact till eight to ten feet out. Car is 47 percent weight on back.Tires are Hoosiers 10.5x33x15. I haven't gotten a clear video from a friend that took a vid of the launch, just a very blurrie version he could text. Before with less motor I saw a best of 1.248 running 8.80s with a 15x33 Goodyear 2078.

Hey Greg, any reason you wouldn’t try a classic 14x32-15 slick? More tread width, less rollout so you can 60 foot better? I am running a 10.5w -31 because that’s all that will fit... With the 4.56 gears and shorter tires I am revving a bit more through the lights, but some say that is the optimum way to ET, by hitting the peak just after 1,000 feet if the motor hold on to the hp on the top...

Just some ideas...

Arnie

I thought I would try some lighter tires. The 10.5x33 tires way 13 lbs less EACH than what I was running. I need a tall 33 inch tire since I have a 4.56 gear. I have 14 inch rims, so my rational was I will be hitting the tire well with that wide rim, almost like the sweet spot of a bigger tire if you follow my logic. The edges on my 15x33s had a funny pattern, at least to my eye. Having put down three runs with 60 fts of 1.276, 1.274, and 1.275 I think it is going to get better. How hard do you hit yours/ Launch rpm off the brake? I only went up to 4,000 rpm this weekend.
The weather station I have is new to me and I quoted what I thought was DA, (2427) but it is listed as "perf density" Then further was a DA number that was higher. Rereading my weather conditions for the 8.854 pass at 1.54.32 I have -a correction of 1.0884, ADR of 90.7, DA of 3275 feet. Can someone shed light on the difference between perf altitude and density altitude?

Call the weather station maker direct and ask them
Please let us know what you find out

Cab, the performance altitude number is a new calculation Computec uses that is considered more accurate than the older Density Altitude. Performance altitude on Saturday at BIR in MN was 2427 ft. BUT the density Altitude, the number most of us are familier with, was 3275 feet! So i am pretty happy knowing i ran what i did and fat as it was tuned.
Computec tech guy said to go by the hp correction factor for best et predictions. For that last run it was 1.0884. Which with sea level conditions would lower my et to 8.704 from 8.854

HP Correction is a good way to compare runs to one another. Its based off current weather conditions against ideal weather conditions. The generally accepted standard being 0 elevation, 59 degrees, 0 percent relative humidity and barometer of 29.92. Many factors change how a racecar will perform for sure. Barometer and vapor pressure, grains of water seems to be the biggest. Obviously altitude plays a role but as you go up in altitude the barometer drops, generally 1.1" per 1000'. So its a very good baseline to compare one run to another. For instance in places like Vegas 1.12-1.15 is a typical HP Corr number. I have seen it as low as 1.09 around the Thanksgiving race and as high as 1.17 in August during the day. Which is mainly altitude and temp related as humidity is generally fairly low. I have never had the chace to run in .999 air or lower but we have come close in the Vette at Norwalk at 1.01. I hear that some of those east coast tracks in the fall see .990 HP Corr days

I have never seen Performance Corrected altitude number. Would be curious what numbers they are using to calculate that and see if the claim is correct. In my experience when it comes to prediction baro, VP and GOW are the biggest contributing factors for my stuff anyway. Outside of track conditions which in some places can be a huge part of it. Also have foudn being on the fat side seems to help repeatability as well.

Very interested to see how your next outings go with the hood/scoop/air cleaner testing. Have you ever considered going to a 16" wheel?

Al, budget limits trying different rims and tires at this point. IYO does methanol react the same way basically as gas, except just less?
One thing about methanol, when humidity gets real hi like over 96 percent, there is a major drop in performance at some point. Like .04 et loss, and no warning when that majic line has been crossed. So late night racing in humid climates can be tricky.
Computecs' comments were that the correction factor uses the same inputs as performance density calcs, and i get the idea that actual grains of water is a much better yard stick than a humidity reading, since humidity is tied to temp and varys a lot from low to hi temps?
I have to say, this info on perf density and correction factors makes me think my combo is close to what the dyno indicates for performance, especisely when you consider the slow 60 ft.
One thing i wonder about; 53.5 percent weight on the front, pulls the front up and carries it to the 60 ft clocks, yet only a 1.274 best 60 ft.
I reserected a post from 2016 where you and Monte both commented at length, and i am trying to absorb some of that knowledge in moving my program forward. I know some or a lot of what i "know" is probably wrong.

What does it 330 ft? Since it carries out to 60 ft maybe its clipping the 60ft clocks with the rear of the front tire. That would slow the 60 ft numbers.
Doug

First pass on sat 8.888
Sunday no hood or aircleaner just scoop 8.854
Both runs carried the front a long way out.
Another pass had a 1.274 but was headed for the wall and lost time straightening it out.

Greg, do you have the other incrementals?...like 330?

8.888 first pass.
8.94 pass car launched to the right, i could feel it slow on the landing, had steering wheel turned slightly to correct.
8.854 pass no hood or aircleaner. Note that it picked up exponetially each increment. All passes within 200 da

How many runs on the motor now?
Is it breaking in the rings still?

Dyno operater said the rings were broken in at 14 pulls or less. Made 24 on the dyno, so they are well past break in. Total of the dyno time, several warmups, and these passes.

For one i would want a back-up verification on the 154mph run...but i def believe the power is there for that and more. Next is the 330 is reflective of a 9.0/8.9^ and as the run progresses the 5.64ish gets into solid 8 zone ET's but that is where it seems to have another 'hurdle' in that something weird is going on with the air inlet track...Of course 60 fts are slower than they should be even for a 3000lb '880 car' ...it's likely spinning to near the 330.

IMO 60's are "slow" because its not with the front tire, speculation based on the distant video but sure looks that way. The converter is not helping with anything down low, especially the 330' numbers. Its clearly way tight for the combo. Better air will help that but only so much. I dont doubt its going to run much better but he has some issues for sure to sort through.

For the mph i ran the car is slow by .264 seconds in the 1/4. It is slow compared to the Walace calculater for 154.32 mph by the following.
60 ft .085
60-330 ft.094
330-660 ft .057
660 -1000 ft .026
1000-1320 ft .020

It really gets rolling at about 1100 feet and the accwleration graph shows it.
Couple of possibilitys. Bad airflow into the throttlebody, or fuel aireation. But the fuel preasure is rock steady on the graph. So,,, gotta be airflow plus maybe too much rpm on the 1/2 shift, as there was a definate drop off just before the shift. Other ideas?

Hey Greg, I have been launching mine at 3,200 rpm to try and slow down the reaction time and ensure it hooks... in 3,000 foot air, I just ran a 8.75 @ 154 w/ a 1.24 sixty foot. Need to adjust a few things to get back to my best times, but cant do much with the Air and higher water grains we are getting.

Cheers,

Arnie

Sounds like my idea of more launch rpm may go too high. Mine seemed to hook fine and carried the front a long way but 60 ft was 1.275.
At 4000rpm. Maybe i should start at 4000 and go lower.