Advancement of fuel delivery?

Pinks All Out 2009!

It was a blast. And, as usual, I can't go to a track and not have tuning issues. :(
I signed up for the G bracket. That's 9.50 to 9.99 cars. I've never had this combination down the 1/4 so it was purely a guess. These brackets were how they divided up the crowd to call them up to the lanes.
My first pass on Friday was a complete disaster. The outside temp was over 100F. Hot. The nitrous bottle pressure got up there past 1200 psi. I was lucky the safety relief didn't blow. I've had high bottle pressures before, but nothing like this.
I went to purge the bottle down just before moving into the water box, and nothing. I was frantic. Pushing the button, wacking the switch panel. But, to no avail. That pass was without nitrous and is not worth mentioning.
Back at the pits I tested the solenoids and all was good. When I put the high bottle pressure back to them, no worky again. I closed the bottle valve and cracked open the hose at the bottle to bleed down some of the pressure in the line. As the pressure came down, the valve started to work. An important lesson at the most inopportune moment.
There is a point where enough pressure will not allow the nitrous solenoid to open.
We grabbed a towel, soaked it with ice water and covered the bottle with it. That brought the pressure down to a perfect 900-950 psi. The next pass was with the towel still on the bottle.
 
Second pass on Friday.
Everything went very well. One heck of a pass.

60 ft: 1.666
330: 4.370 New best with the new combination.
660: 6.388 @ 122.79 New 1/8 mile best with the new combination.
1000: 8.109
1320: 9.564 @ 154.87 New mph best for the car.

The previous best mph was around 146. The difference between that and 155 is pretty impressive. I almost dropped my laundry on that one.

I wonder how much hp it takes to be down the first have of the pass by 3 to 4 mph and make up for it in the second half of the pass and still crank out a 155 mph.

The last pass for us on Saturday was a 9.6x @ 152.x. Down a bit from the previous pass. The car was doing some skating the last half of the pass on this run. I was a little disappointed until we found the reason. We had developed a pretty healthy oil leak coming from the back of the motor, and it was coating even the rear tail lights. The rear tires were showing signs that oil had been spraying on them.
Cheryl got a video of the last pass. The other car jumped out ahead at the start and had about a 4 to 5 car lead by the 330 mark. Then... she came on boost and we reeled him in, blasting past him at the finish for the win light. You can hear in the video the people that were a little astonished by that. Some of the quotes were, "?uck!", "##sus!", (some other well known exclamations), "What the he@# is...?", "He had a 2 tenths head start. That guys pretty unhappy."
 
They ended up selecting a 10.30 to 10.50 grouping. A mix of the E and F brackets.

I have the aux channel of the boost controller setup to read manifold boost pressure for the pass. Over the weekend, boost ranged from 26 to 27 psi. Max boost at one point being 27.1 psi.

The mixture on the top end only needed to be leaned at the lower rpms (after a shift) one percent. The top end was perfect.
125 to 145 kPa was on the lean side. In the 13s at some short spots.
The transition at 3800 @ 98 kPa was still just a tad bit too rich.
I only made 1 percent corrections at this event. I didn't dare throw the tuneup off. It was working pretty good as it was.

RPM at the finish line was 7550. The new tire size did its job. With the 28" tires, I would have reached over 7800 rpm before the finish line. I've calculated that the 29.5s grow by the end of the 1/4 by around 9%. When up to speed and hitting some bumps in the track, I could hear tire to fender lip contact.

Fun, but hot weekend.
 
Sorry you didn't get picked but getting 9 mph more out to the car is great. Once you get more time to finish it you might even get another 10. Did anyone take a vid of the final run? That's the one I'd like to see.
 
Don i know your problems were with the NOS system you have but dont you think it would be simpler to go to big injectors like Mike Moran has on his car?

You may make more power too.

Just food for thought.
 
Sorry you didn't get picked but getting 9 mph more out to the car is great. Once you get more time to finish it you might even get another 10. Did anyone take a vid of the final run? That's the one I'd like to see.
The link I put in post #524 was the last run.
 
Don i know your problems were with the NOS system you have but dont you think it would be simpler to go to big injectors like Mike Moran has on his car?

You may make more power too.

Just food for thought.
It would be nicer to use the Moran injectors. They would allow much more range if I decided to start pushing big boost numbers. Easier to tune in also. Then I'd have to upgrade the fuel delivery too. The price to do all that is a little scary. Heck, the system as I have it now is doing the job without insurmountable problems. The only way I'll change it out is if I get tired of 155 in the 1/4. That will not be anytime soon.
 
The incrementals on the last pass (video pass) were:

Him / Me
R/T .122 / .191
60' 1.435 / 1.690
330 4.088 / 4.412
1/8 6.336 / 6.451
MPH 109.01 / 121.26
1000 8.300 / 8.196
1/4 9.98 / 9.671
MPH 133.51 / 152.87
 
I made a very simple modification to the transmission, since I had it out to replace the cam plug anyway. The result so far, is a quicker responce when winging the engine. It feels like I took 20-25 pounds off the flexplate/converter combination. :confused:
Another affect of the modification is that the stall speed of the torque converter at 0 boost is now 400 rpm higher. Where it was 2,400 before, it's now 2,825 rpm. :confused:
I did not expect these affects from this modification at all. Very interesting indeed.
It will be interesting to see if there is a change to the stall speed with the nitrous hit. Before it was around 3200 rpm.

I've been doing sim work with my 60 foot (1.69 sec) and found out some interesting stuff about my nitrous hit. At the onset of the hit the nitrous hp value peaks to around 225 hp. Soon after the peak, it ramps down to less than a 50 hp nitrous hit value. I'm sure it's the chilling effect to the combustion process that the nitrous paired with the methanol presents. It's too cold for an efficient/complete combustion.
I'm going to play around with the mixture and particularly the timing to see if I can get some heat into the combustion process during this chill period. If it's true that the hit is dropping to less than 50 hp, then I have way too much timing retard going on. That certainly is not helping matters. I may end up having to pair the nitrous with gasoline.
 
Would logging EGTs help get the ideal timing for a launch?
If I could trust that there wasn't any delay in the reading it would be a good way of tuning that region. It seems the the EGT gauge doesn't immediately come to a stable reading. It takes almost the whole 1/8 mile to come to a stable max EGT reading. The region I'm concerned about is happening during the first few seconds of the run.
 
I made a very simple modification to the transmission, since I had it out to replace the cam plug anyway. The result so far, is a quicker responce when winging the engine. It feels like I took 20-25 pounds off the flexplate/converter combination. :confused:
Another affect of the modification is that the stall speed of the torque converter at 0 boost is now 400 rpm higher. Where it was 2,400 before, it's now 2,825 rpm. :confused:
.

Was this mod TH400 specific ? Fluid or rotating mass modified ? Just curious ;) Very interesting stuff !
 
Don't know if changing to gas will help you but it might be a posibility to do a mix of fuel. Try adding some gas to the alkiy and see if this helps before you go to straight gas. That mey bive you an advantage to increase temp and get a better burn.
 
If I could trust that there wasn't any delay in the reading it would be a good way of tuning that region. It seems the the EGT gauge doesn't immediately come to a stable reading. It takes almost the whole 1/8 mile to come to a stable max EGT reading. The region I'm concerned about is happening during the first few seconds of the run.

If you are logging it is there a real time delay to be had there versus what the ECM can register?

I am trying to figure out how to ask that question and it make sense......
 
Don't know if changing to gas will help you but it might be a posibility to do a mix of fuel. Try adding some gas to the alkiy and see if this helps before you go to straight gas. That mey bive you an advantage to increase temp and get a better burn.

I'd rather not mix fuels. Being just slightly off on the percentages would have an affect on the target a/f ratios. The car is enough of a tuning headache as it is.

I've heard of it before with an alcohol engine people using gasoline with nitrous. The gasoline has a lower latent heat of vaporization value than the methanol, so it doesn't add to cool the charge nearly as much as the methanol.
 
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