Advancement of fuel delivery?

[Alky V6]

For the nitrous system I installed a delay box that would keep the fuel side of the system on for a programmed amount of time after the nitrous was shut down. This made up for the accumulating affect of the space volume between the activation solenoid and the nozzle jets. The accumulating affect was only a problem on the high pressure oxidizer side of the system. The amount of delay time that was needed was .7 seconds. Not a perfect solution, but well enough to keep the engine attitude stable.

I was able to test the nitrous system alone, without the aux fuel, by simply limiting max rpm during these particular tests. 6000 rpm was the limit.

 

[Alky V6]

Next was the aux fuel system. I had first started by trying to time a cut back of injector pw at the time of aux fuel activation (16 psi). I quickly learned that the cut back was not necessary. I then learned that additional fuel from the electronic injectors was needed as the aux fuel was activated. I quickly stepped up the electronic injectors to max duty cycle right at the point of aux fuel activation.

This is what I learned was happening with the aux fuel system at activation. Dreaded space volume again. The space volume between the aux fuel activation solenoid and the mechanical injector nozzle orifices is filled with air until the aux solenoid is activated. When the aux fuel solenoid is activated, the fuel column, which is at a pressure differential of 45 psi, rams the air from the space volume out of the injector nozzles at 45 psi. This continues to occur until the column of fuel has reached the nozzles. Approximately .5 seconds.

Imagine taking a shop air gun and pointing it down into the throat of the intake port and blasting pressurized air down the intake port. For a split second, this is what is happening when the aux fuel solenoid is activated.

This is a new form of forced induction in itself! Imagine someone using a compressed air bottle to force feed air down an intake port. That's another story though.

 

[Alky V6]

The blast of air from the aux fuel system demands a matching shot of extra fuel until the fuel column can reach the orifices of the nozzles. That is why the electronic injectors must be pulsed at max duty cycle right at the point of aux fuel activation. In fact, from the point of aux fuel activation on, the electronic injectors are pulsed at max duty cycle, which means that the actual injector on time must be decreased as engine rpm increases to maintain an 80 to 85 percent duty cycle. At present, I'm using 85 percent as a max duty cycle on the injectors. Fuel delivery appears to maintain stability at that duty cycle. At least, in my situation.

 

[Alky V6]

This last problem and solution turned out to be the fix for the entire fuel system arrangement.

Problem: Even with the electronic injectors being stepped up to max duty cycle at 16 psi to augment the shot of air from the mechanical nozzles, I would get a short lean spike at the tail end of this transition period.

This is what was happening. Soon after reaching 16 psi, the electronic injector on-time needed to be scaled back, per rpm and map, to maintain the target 85 percent duty cycle. I was simply running out of injector on-time to cover the aux fuel transition period.

 

[Alky V6]

The Solution: Very simple really. I moved the activation point of the aux fuel system to a lower rpm and map point. This gave me much more electronic injector on-time range and time before having to start scaling back the injector on-time due to max duty cycle limits. It also gave me the chance to inject much more fuel at the start of aux fuel activation. I am presently maxing out the electronic injector duty cycle at a lower rpm and map, yielding me more fuel per intake cycle. The injectors maintain 85 percent for the remainder of the rpm/map rise.

With all fuel systems activated together, the rpm and map rise is practically straight line with no noticeable upsetting of the engine. There appears to still be now two short lean spikes during the activation or deactivation of each system, but the spikes are very short, reasonable and not enough to upset the engine.

 

[Alky V6]

The next simple test will be to program the nitrous fuel side delay box to stay on for the entire pass. This is an easy way to inject about 40 lb/hr additional fuel to see if the engine wants it or not. If it likes it, I'll be ordering larger mechanical injector nozzles. Larger orifices at the mechanical injection nozzles will also mean that the blast of air from the space volume should be with less force, although the same volume, and the time span of transition will be shorter. Possibly more tuning to follow. It never ends, does it.

 

[Alky V6]

Here is a video of all the runs made on a Sunday when the tuning first came together. There's still more in it.

YouTube - DRW Buick Grand National at WCN @ Speedworld 2007

There are videos of better quality at our website.

DRW Transmission: Auto transmission service, repair and high performance upgrades.

Notice how the car leaves the line like a naturally aspirated car. This type of launch should make bracket racing with a turbocharger much easier. Now, instead of the usual drama at the starting line associated with a turbo car, a person can concentrate on a good reaction time.

 

[Dave Flanders]

Don - I've followed the progress of your car for some time now and really enjoy seeing all the updates. Keep it up!

Couple of questions - do you know roughly how much fuel (in pounds per hour) is going in the motor at max power? Reason I ask is on my methanol powered Mustang the total flow is higher than the calculated horsepower would suggest - this alone doesn't surprise me as Top Alcohol cars run much more than needed for cooling and detonation suppression - but just how much more was a shock.

I've found the same as you - every time you think the motor wants less alcohol it almost always wants more...

Also I would love to see what your intake port temps are. When I checked mine a year or so ago I found that 185 degrees in the plenum turned into 90 degrees in the runner (after the fuel nozzles).

A friend of mine with a 460 NA was reading 34 degrees in the intake runner at the end of a run....

Most blower guys seem to shoot for about 140 and feel you can in fact be too cool. I suspect it's to help vaporize the huge fuel volume which makes me wonder what is happening on yours with the nitrous flowing? And would it be more beneficial to feed the nitrous pre turbo?

 

[Alky V6]

Don - I've followed the progress of your car for some time now and really enjoy seeing all the updates. Keep it up!

Couple of questions - do you know roughly how much fuel (in pounds per hour) is going in the motor at max power? Reason I ask is on my methanol powered Mustang the total flow is higher than the calculated horsepower would suggest - this alone doesn't surprise me as Top Alcohol cars run much more than needed for cooling and detonation suppression - but just how much more was a shock.

I've found the same as you - every time you think the motor wants less alcohol it almost always wants more...

Also I would love to see what your intake port temps are. When I checked mine a year or so ago I found that 185 degrees in the plenum turned into 90 degrees in the runner (after the fuel nozzles).

A friend of mine with a 460 NA was reading 34 degrees in the intake runner at the end of a run....

Most blower guys seem to shoot for about 140 and feel you can in fact be too cool. I suspect it's to help vaporize the huge fuel volume which makes me wonder what is happening on yours with the nitrous flowing? And would it be more beneficial to feed the nitrous pre turbo?

Hi Dave. So glad you're enjoying the writeup.

The only intake temperature measurement I'm taking is at the up pipe. This is before any fuel is mixed. I am using a liquid intercooler, so keep that in mind. The water in the intercooler is not being circulated during the run. Though I do have a small tank and a pump, at this point I'm not circulating. The IAT is 89.6 degrees F at the start of the run and ends up at 159.8 F at the end.

The amount of fuel is:
160 lb/hr injectors at 85% duty cycle = 136 lb/hr per cylinder.
80 lb/hr per cylinder from the constant flow mechanical injection nozzles.
1,296 lb/hr at the top end for all cylinder?

Plus another 43 lb/hr per cylinder from the nitrous nozzles when the nitrous system is being activated.

The reason I went with port injection was because I wanted to be absolutely sure I had equal distribution. A newbie trying not to blow his motor up. Another reason was that I saw the chance to use the burst of nitrous gas to better atomize the alcohol fuel directly in the runner. The nitrous nozzles I designed shoot the nitrous spray right through a fan spray of alcohol.

If I do install a 2nd stage of nitrous, it will be injected dry, before the compressor. This 2nd stage will be activated as the first stage comes off at 16 psi. The HP rating of the 2nd stage will be smaller than the first stage.

The present port injected nitrous is working exactly as I had hoped it would. It hits with a soft ramp up of power, and when it shuts down, the turbo takes over in a fashion that makes it practically impossible to tell when the nitrous has turned off. Even when I study the datalogs, the only way I can tell when the nitrous has shut down is by the actual MAP number. I know when I see 194 kPa, the nitrous has been switched off. The rpm and map trace lines are rock steady. It's amazing. A seamless transfer of power. As it stands, I have no reason to change it in anyway.

I'll keep updating as more information comes to me. This weekend there's 3 day of racing at my local track, I should be able to get a bunch of testing in.

 

[Alky V6]

For those wondering what the a/f ratio is for nitrous and methanol.

Stoich for nitrous to methanol is 4.13 to one.

Of course, I'm running a rich mixture with my nitrous system. It's an amazing 2.4 to one.

 

[Dave Flanders]

The only intake temperature measurement I'm taking is at the up pipe. This is before any fuel is mixed. I am using a liquid intercooler, so keep that in mind. The water in the intercooler is not being circulated during the run. Though I do have a small tank and a pump, at this point I'm not circulating. The IAT is 89.6 degrees F at the start of the run and ends up at 159.8 F at the end.

That sounds close to mine - I have a small A/W IC with ambient temp water circulating. Didn't check the IAT this year but at 40psi boost I would expect to see 220+ after IC and I am seeing 95 in the runner.

The amount of fuel is:
160 lb/hr injectors at 85% duty cycle = 136 lb/hr per cylinder.
80 lb/hr per cylinder from the constant flow mechanical injection nozzles.
1,296 lb/hr at the top end for all cylinder?.

What kind of FWHP are you figuring? This is what I'm wondering about - according to some dyno info and online calculators I'm making around 850-900FWHP but am pushing around 1650+ pounds per hour of fuel. The more I give it the quicker it runs although it might be time to try a high speed leanout - mine is all mechanical injection btw.

I could see needing that much if I didn't have an IC or a cooling system but with those in place it seems a little high.

The reason I went with port injection was because I wanted to be absolutely sure I had equal distribution. A newbie trying not to blow his motor up. Another reason was that I saw the chance to use the burst of nitrous gas to better atomize the alcohol fuel directly in the runner. The nitrous nozzles I designed shoot the nitrous spray right through a fan spray of alcohol.

I've finally taken the time to set up a tank and pump on the workbench to test different nozzles and spray patterns, it was surprising how good/bad different ones were at varying pressures.

 

[Alky V6]

That sounds close to mine - I have a small A/W IC with ambient temp water circulating. Didn't check the IAT this year but at 40psi boost I would expect to see 220+ after IC and I am seeing 95 in the runner.

I think I forgot to mention, those figures were at a max of 30 psi with it dropping with rpm to 25 by shift point. And then peaking again to 30 psi after each shift.

What kind of FWHP are you figuring? This is what I'm wondering about - according to some dyno info and online calculators I'm making around 850-900FWHP but am pushing around 1650+ pounds per hour of fuel. The more I give it the quicker it runs although it might be time to try a high speed leanout - mine is all mechanical injection btw.

I could see needing that much if I didn't have an IC or a cooling system but with those in place it seems a little high.

My calculations come up with around 860 BHP with my boost problem. My setup has a natural leanout property to it. I reach max injector duty cycle by around 8 psi and the constant flow nozzles are just that so my fuel strength lessens with increased rpm. Haven't tried adding or taking away fuel yet. I understand what your saying. All you can do is try something different and see what you get.

I've finally taken the time to set up a tank and pump on the workbench to test different nozzles and spray patterns, it was surprising how good/bad different ones were at varying pressures.

What kind of results did you get from the Edelbrock nozzles? Mine follow their design.

 

[Dave Flanders]

The nozzles I have been using were from Ron's (Flying Toilet). It is a center hole that's bisected by a countersunk round hole. At higher pressures (120 on the bench, I run 200 in the car) it comes out as a roughly hollow cone pattern. Lots of splashing but it does fill the runner. Unfortunately at low pressure fuel just dribbles out like a kitchen faucet

I have been trying some fan spray nozzles from N.O.S. and they are more like a normal injection nozzle with a 45 degree whistle cut across the end. At my lower idle and staging pressures of 15-25psi they do atomize much better than the Ron's but at high pressure it is a flat and wide discharge pattern. I use drop in nitrous jets to size them and plan on trying to modify the nozzle ends to see what happens.

I can foresee having to run 3 nozzles per runner next year just to keep the jets to a reasonable size to help with atomization.

Those straight discharge nozzles at your runner entrance - what orifice size are they equivalent to? And do they have a small screen at the tip?

 

[Alky V6]

The nozzles I have been using were from Ron's (Flying Toilet). It is a center hole that's bisected by a countersunk round hole. At higher pressures (120 on the bench, I run 200 in the car) it comes out as a roughly hollow cone pattern. Lots of splashing but it does fill the runner. Unfortunately at low pressure fuel just dribbles out like a kitchen faucet

I have been trying some fan spray nozzles from N.O.S. and they are more like a normal injection nozzle with a 45 degree whistle cut across the end. At my lower idle and staging pressures of 15-25psi they do atomize much better than the Ron's but at high pressure it is a flat and wide discharge pattern. I use drop in nitrous jets to size them and plan on trying to modify the nozzle ends to see what happens.

I can foresee having to run 3 nozzles per runner next year just to keep the jets to a reasonable size to help with atomization.

Those straight discharge nozzles at your runner entrance - what orifice size are they equivalent to? And do they have a small screen at the tip?

I thought you were talking about nitrous nozzles. I didn't realize you were talking about fuel nozzles. Mine are aerated nozzles with the screened tips, like you were asking about. The orifice size of each nozzle is at .041" if I remember right without checking my notes. They're manufactured by Kinsler.

I see your dilemma. That is what's great about running a combination electronic and mechanical nozzle injection. At idle and low speeds, I run off the electronic injectors that give me great atomization at a typical rail pressure of 42 psi. At 8 psi manifold boost a solenoid energizes to allow fuel to be fed to the mechanical nozzles at the same pressure as the electronic system, 42 psi. The fuel pressure is referenced to manifold boost, so that there is a rise of one psi fuel pressure for every psi of boost pressure. I realize this pressure is not the optimum pressure for mechanical nozzles. Even Kinsler wasn't too sure how it would work, but it seems to be working well enough in my situation. I think that by the time the mechanical nozzles are turned on, there is enough turbulence in the intake runner from normal pressure pulsations to break the fuel up after it leaves the nozzles. One other thing that might be helping out is the fact that my port and valve size is on the smaller side for what I'm trying to do. Maybe the high port velocities are helping to break up the fuel too.

For your situation, I would suggest that you look at aerated nozzles carefully.

 

[Alky V6]

I should update this thread. I know there are some that are following it closely. The last outing was an absolute success. I have found the ceiling as far as the tuneup of this engine configuration goes. Some new records for the car were had. The turbocharger size turned out to be the limiting factor. I kept pushing the spring tension on the wastegate and raising the boost controller until she just wouldn't put out anymore. The max was an intermittent 32 psi with the average being 30 to 31. The boost would still drop with engine rpm between shifts, but the most it dropped to was 29 with occasional 28s. The boost rise time also steepened as the wastegate was made stronger. It actually got to a point where I had to turn back the spring tension because the rise was too quick. Another thing I noticed was that the 1-2 shift became more violent with the stronger wastegate spring tension. It broke the tires loose on the 1-2 on one run before turning the adjustment back a little. Although, the tires were always on the limit of traction on the 1-2 with this car and tight torque converter combo.

I've established the calculated peak HP to be around 930. Not bad for a measely destroked 224 cubed, small valve headed, too large a cammed, frankenstein fuel systemed, nitrous exploding, too low a T/C stalled, exhaust headers too long, intake runners too short, no distributor, crap Electromotive ECMed, there just ain't no way in hell it's going to work... little BUICK V6.

New 1/8 mile best performance for the car:
1.289 60 ft.
3.704 ET at the 330 mark.
94.762 mph at the 330 mark.
5.732 ET at the 660 mark.
122.145 mph at the 660 mark.

At max boost setting for this combo, the a/f ratio weakened a bit, but was still plenty safe. In fact, it's my new target a/f ratio. It reads out as 10.5 to 10.6 on the O2 meter, calibrated to readout gas numbers. The actual a/f ratio calculates out to be 4.63 to one.

Here's a link to my latest video highlighting the effectiveness of using nitrous to spool the turbo.
http://www.drwtransmission.com/Videos/Vids2008/Barona 123107 don HQ.wmv

 

[Alky V6]

One thing I should note about my calculated HP figure. Since my boost level is dropping with rpm, my peak hp figure ends up being at a lower rpm than it should be if the turbo was able to supply a stable boost pressure throughout the optimum rpm band for this engine. With more rpm and boost drop, so drops the hp level of the engine. My calcs suggest that hp is peaking at about 6200 rpm. This engine should be peaking at 6750 to 7000 rpm with the correct turbo. Since boost and hp are dropping at the upper rpm range, the mph figure for a 1/4 mile pass will not be up to par, crossing the finish line at around 7500 to 7600 rpm during the last 1/4 mile outing.

There's more still in it, boys!

 

[TurboTR]

Very, very nice Now time to cam up and turbo up and hit the 8's!

TurboTR

 

[Alky V6]

The Next Phase.

I've been batting around what the next phase of this project should be. I'm seriously toying with the idea of installing a 2nd stage of nitrous to be activated after the port system has shut down. Very simple and similar to what Scott has done with his truck.

It will be:
-A small system. 50 to 100 HP.
-Injected 3 feet before the turbo compressor. This way the nitrous has the best opportunity to reduce intake charge temp before reaching the compressor wheel.
-A dry system.
-Activated at 16 psi, after the large system used for launching has shut down.

This system will help me in a few ways:
-Create less airflow demand on the air intake (filtration) system.
-Allow a reduced boost target which will further help reduce intake charge temperature and allow the T76 turbo to run in a more efficient range.
-Help the intercooler to reduce intake charge temperature.
-Spare me the expense of switching to a larger turbo and the fabricating that would be involved in fitting the larger turbo.
-Allow me to keep my present tune for launching, which is working very, very well right now.

 

[Chevota]

So, how did "it" work? Updates?

Scott Wile

 

[Alky V6]

New data has been slow coming in. After the track rental at Fontana I put the car down to fix, what turned out to be three small nagging oil leaks. One was a split that developed in the turbo oil drain pipe. The ugly stock one. I replaced it with one braided SS line. I remembered what you said about that pipe Scott.

The last time out with the car was April 5th at Barona. The fuel system is basically unchanged since the last update, except for more fine tuning to the fuel map. I had an area in the upper midrange that I had purposely left very rich to help mask any lean spots that might occur during the turning on of the auxiliary fuel @ 8 psi and the turning off of the nitrous system @ 16 psi. After identifying and focusing in on the areas where the lean spots did ultimately occur from all the fueling transitions, and finalizing the required extra pw that was necessary to tame down the lean spots, I started bringing other areas of the upper midrange back inline with the more basic fuel curve. In those areas I ended up pulling out around 40% of electronic injector PW. Could you imagine going 40% rich with gasoline? To say the least, that produced some hidden horsepower in that area of the fuel map. Before the leaning, when I studied the launch of the car, you could hear the rich spot in the engine sound. It almost appeared as though the car had launch traction control. You could hear three different power levels in the first 50 feet of the launch. The last big rise in power level being, just before the 1-2 shift, after the rich spot of the fuel map had been passed over and the mixture was leaning out to what it needed to be. This extra rich spot also entailed the very end of the nitrous activation area of the fuel map, which tamed down the nitrous HP level quite a bit also. Now, after leaning that area out, the engine power is smooth up to the point that the nitrous turns off. There's a noticeable drop in power as the turbo spools up further and takes over. In the future I'm going to put that turn off point for the nitrous on one of the GPOs of the controller so I can play with different turn off points.

This last time out at Barona I tried some different launching setups. First, I made a few runs without nitrous to make sure that the areas I had leaned out were still giving me safe a/f ratios. After two runs I determined that everything looked good with the fuel map. I love it when a plan comes together. The next run was with the nitrous included. It felt really good, but I think the timing clock had a hiccup and produced a 5.34 ET with a 0.9x 60 foot. Unless I was able to back that one up, I was just going to ignore it. It didn't feel that good. The rest of the runs weren't very clean, so I don't have any new concrete times and mph for the car. One interesting note was one of the runs I made without the nitrous. The car basically rolled out like a pig to about the 60 foot mark and then went hog wild. It produced a 6.8x at 119+ mph.

One of the runs did get a little high in the air and out of shape, so the next time out I'll have the wheelie bars on it. I also have on order a multi-circuit delay box that I'm going to use to control the nitrous activation and transbrake release. That way I can precisely control the time between nitrous activation and the release of the transbrake. It's just impossible to do manually and get consistent launch attitudes. Just the difference of a few tenths of a second makes a large difference as to whether the car leaves very tame or goes hog wild, in the air and out of shape. It should be fun dialing in the delays and trying different stradegies.

The newest goal is to click off a 5.6x E.T. in the 1/8 with an old school T76 before thinking of moving to a larger turbo.