Advancement of fuel delivery?

[Alky V6]

After studying the data logs, I've determined that the larger shot is not worth the extra spent nitrous. There are trade offs going on between the last shot size and this larger one that is netting practically the same performance, if not just a little worse.

It is finally time to look at the torque converter. The potential gain here is going to be enormous.

 

[Alky V6]

I'm running into an interesting phenomenon with the car and the 364 n2o shot. On the last run this last Sunday, the car began to surge while on the hit. I don't think it was turbocharger compressor surge. I've heard of large nitrous hits causing surging. I wonder if that's what it was? The nitrous bottle pressure equilibrium becoming unstable and pulsating? Maybe it's time to check into a NANO system?

 

[pwr6kid]

Could you run a larger bottle or two bottles to help with this? How many pound bottle are you running? If you find some good info on the nano setup can you post a link or pm me it.

 

[Alky V6]

Could you run a larger bottle or two bottles to help with this? How many pound bottle are you running? If you find some good info on the nano setup can you post a link or pm me it.

I would guess that either of your suggestions would help. I'll share whatever info I find on this problem.

 

[Alky V6]

Some interesting discoveries.
Thermo-hydraulic resonance. A condition where some of the liquid nitrous in a delivery system converts to a gaseous state and forms a gas or foam pocket in the delivery system. This pocket is eventually flushed into the engine by liquid nitrous, then another pocket forms and is flushed again, and the process continues over and over. This causes a varying n/f ratio since nitrous being delivered in gaseous form gives a different n/f ratio than nitrous being delivered in liquid form. The surges in power can be up to 50 hp in a second. This sounds just like what I experienced.

I guess the solution to preventing this problem might be to keep the delivery system as cool as possible (use heat barrier sleeves), good purging before activation, and keep plumbing volumes to a minimum.
It just so happens that on Sunday I was being very conservative with the purging.

 

[Alky V6]

A recent torque converter change has brought the 60 foot to 1.378 second.
The stall of the new TC is about 1,000 rpm higher when on the nitrous than it was with the previous TC.
The 364 hp nitrous shot was kept for the initial testing with the new TC, and the performance was acceptable. With the higher rpm at the launch and the fixed delivery rate of the nitrous system, the total amount of nitrous/fuel taken into the combustion chamber on each intake stroke is less than what it was with the lower stall TC. So the engine is essentially seeing a smaller nitrous shot due to the increased TC stall and engine speed.

So, does this mean that the new TC stall speed has now made the next higher nitrous shot size a viable option worth exploring? Would a higher shot push the 60 foot even lower? Hmmm. Very curious, indeed.

Is the nitrous system set up well enough to support the 390 shot? Will it flow the required volumes of nitrous and fuel? The plot thickens. Stay tuned, gentlemen. We have not reached the end yet.

 

[Alky V6]

An increase to 33/33 jets will raise the hp rating to 393 from the 32/32 364 hp rating. Even if only 20 more hp is realized from the jetting change, the DR sim shows that the stall on this TC will rise 200 rpm and the 60 foot should be cut down by half a tenth, which pretty well follows the increases realized in the past after similar size jetting changes.
The nitrous and fuel solenoids are hp flow limited to 450 and 600+ respectfully.

Up to this point, the ALS is still active with little change in behavior, even after all the recent tuning changes.

 

[Alky V6]

The limit of what the nitrous/methanol mix can do for me has finally been realized.
When I stepped up to the 364 hp shot size, after tuning things in, I was able to drop the duration of the nitrous on-time after transbrake release by .800 of a second to help control how fast the boost was rising before the 1-2 shift.
After stepping up to the 393 hp shot size, I had to put that .800 of a second back into the nitrous on-time inorder to get the boost rise rate back to the rise rate I was getting with the 364 shot with the less total nitrous on-time, even with the als being active in both cases. The shot size had gotten too large and was over chilling the charge in the cylinder.

I will be stepping back to the 364 hp shot. That is obviously the sweet spot for the nitrous system with this combination.

 

[Alky V6]

Advancements continue to be made. These are links to the continuing saga.

http://www.turbobuick.com/forums/turbo-videos-picture-library/325333-new-major-tuning-discovery.html

http://www.turbobuick.com/forums/al...ous-methanol-anti-lag-system-afterburner.html

http://www.turbobuick.com/forums/tu...ry/327098-ultimate-turbo-anti-lag-system.html

http://www.turbobuick.com/forums/tu...-latest-progress-monster-s510-91mm-turbo.html

http://www.turbobuick.com/forums/ti...bo-buick-v6-does-impossible-8-76-158-7-a.html

 

[Alky V6]

The latest fuel map (Alky 3.2 nos 4i) rendered on Motec software.

 

[Alky V6]

The latest boost rise path through the fuel map.
Boost starting to build at 3,780 rpm.

 

[Alky V6]

The datalog of the latest 1/8 mile best run with the car. 1.27 60', 5.57 at 126+.
Launch rpm and map: 5100, 144 kPa. Timeline: 45.22
Nitrous still on at the launch. Launch occurred 1.7 sec after nitrous activation. Shut off at 175 kPa MAP, .30 sec after launch.
1-2 shift: 7751 to 6939, 812 rpm drop. Timeline: 47.14 - 47.42
2-3 shift: 7694 to 7030, 664 rpm drop. Timeline: 49.34 - 49.54
RPM flat at 7230 for the last one second of the run.

 

[Alky V6]

Studying the fuel maps I just posted, you can see where this cam starts to kick in, just after 4,100 rpm.
It's also not very difficult to see where the peak torque of the engine is with this cam, 5,700 rpm.
Interesting to see that the fueling doesn't drop off much all the way to 7,800 rpm, showing that the power curve of this combination is rather flat from 5,700 rpm all the way through to 7,800 rpm. A solid 2,000+ rpm span.

You have to ignore the section of the fuel map after the large drop off at 238 kPa MAP. The fuel delivery of the constant flow fuel nozzles plus the flow from the electronic fuel injection nozzles gives a picture in the fuel map that is not a true representation of all the fuel that is being fed to the cylinders at the different rpm levels. It is somewhat representative at the different MAP levels, though. Just at a stepped down level.

 

[Alky V6]

Looking at the datalog. If you study the beginning of the nitrous hit (you can tell that point by the ignition retard) you will notice how the rpm jumps to a higher level, but slowly levels back down, and finally takes on a consistent climb rate associated with a consistent rise in the MAP level.
This is a good example of how the rated hp level of a nitrous/methanol mix changes even throughout the timespan of the hit. When the hit first occurs, cylinder temps are at a certain level after having warmed up during normal idling and the burnout. As the cooling nitrous/methanol mixture cools combustion temperatures down, you can see how the power level slowly drops. The only thing really keeping the rpm rising being the rising MAP level.
You also have to keep in mind that I'm running an abnormally, very rich nitrous/methanol mixture.

 

[Alky V6]

An interesting occurrence at the finish of the run with this particular datalog. Notice the driveshaft speed (GPIO7) as I get out of the throttle and the MAP level is dropping.
I think what was happening was the a/f mixture may have moved a little too rich at the end of the run, and as I got off the throttle and the MAP level began to drop, the fuel mixture leaned into a more desired range and it broke the tires loose. A little surprising when I first caught that when I was reviewing the datalog.

 

[Alky V6]

An interesting occurrence at the finish of the run with this particular datalog. Notice the driveshaft speed (GPIO7) as I get out of the throttle and the MAP level is dropping.
I think what was happening was the a/f mixture may have moved a little too rich at the end of the run, and as I got off the throttle and the MAP level began to drop, the fuel mixture leaned into a more desired range and it broke the tires loose. A little surprising when I first caught that when I was reviewing the datalog.

I think I've figured out what the output speed sensor spike is at the end of the run as I'm releasing the throttle.
It is the chassis unloading the rear tires as the power is coming off.
A promising sign that the chassis is doing some work at trying to keep the tires planted on the top end.