Nitrous/Methanol Anti-Lag System Afterburner!
- Thread starter Alky V6
- Start date
grocerygetter
Active Member
- Joined
- Mar 8, 2005
just to be devils advocate....when injecting a 'wet' shot into an intake stream the mixture is not 'lit' until it gets down into the cumbustion chamber. You will essentially be lighting this thing off right outside the jet...I keep thinking of a lighter in front of a can of hairsrpay...it burns upstream back to the can. What stops that?
That would be what I hope happens. If it lights off right at the nozzle, that would mean plenty of heat for the turbine wheel.
The fuel and nitrous are separated in the nozzle, so the chance of something happening up into the nozzle is unlikely.
I see this method of burning oxygen/fuel in the exhaust system as no different than the method used by others in turbo class racing where the rules force them to do the same thing without nitrous oxide.
The pop and bang method of als is air and fuel combusting in the exhaust system. The problem I see with that particular method is that it is very hard to control the combustion process and you end up with a very erratic and harsh type of combustion, evidenced by the very erratic popping out of the exhaust. The erratic combustion and resulting pressure spikes are very hard on the machinery, evidenced by a quick trip through the pits at a major turbo racing event. Broken turbo shafts.
With the method I'm proposing, the nitrous nozzle will supply a constant flow of fuel and oxidizer. The resulting combustion process will be as smooth as glass. The only thing you should hear out of the exhaust is the whining of the turbine wheel.
The pop and bang method of als is air and fuel combusting in the exhaust system. The problem I see with that particular method is that it is very hard to control the combustion process and you end up with a very erratic and harsh type of combustion, evidenced by the very erratic popping out of the exhaust. The erratic combustion and resulting pressure spikes are very hard on the machinery, evidenced by a quick trip through the pits at a major turbo racing event. Broken turbo shafts.
With the method I'm proposing, the nitrous nozzle will supply a constant flow of fuel and oxidizer. The resulting combustion process will be as smooth as glass. The only thing you should hear out of the exhaust is the whining of the turbine wheel.
The plumbing hardware has been ordered. I'm going to wire the control of the new pair of solenoids to an unused circuit on the transbrake and primary nitrous system delay box. With the aux nitrous system on a separate delay box circuit, I should be able to play with the timing of the activation of the auxiliary nitrous system (als afterburner) in relation to the activation of the primary nitrous system. In other words, I'll give the als a chance to light off before I activate the afterburner.
I wonder what this thing is going to sounds like?
I wonder what this thing is going to sounds like?
The Tee plumbing into the nitrous and fuel supplies are in. The nitrous side solenoid is mounted,. looks very cool by the way, and I'm waiting for the second alky solenoid to show up, along with the plumbing hardware for between the solenoids and the injection nozzle. As I was writing this, Cheryl came into the office to show me a package that came in. It's the other parts! Time to finish the plumbing.
I couldn't find steel nuts for the nozzle side of the tubing from solenoids to nozzle, so I'll be using aluminum nuts, and keeping an eye on how it holds up after a few passes.
The controls of the afterburner stage will be simple. The solenoids for the afterburner stage will not be staggered as far as activation and turn off. If it ends up, and I'm sure it will, that the nitrous gets to the nozzle before the fuel, that will only cause a lean spike at the start of the hit and hopefully the lean spike may help in lighting off the afterburner. Staggered activation is still planned as far as the primary nitrous stage coming on a split second before the afterburner stage.
There's an event at the track this weekend that I'm planning to make. I wasn't planning on testing the afterburner so soon, but since the parts came in so quickly,... maybe. :wink:
Time to finish the plumbing.I couldn't find steel nuts for the nozzle side of the tubing from solenoids to nozzle, so I'll be using aluminum nuts, and keeping an eye on how it holds up after a few passes.
The controls of the afterburner stage will be simple. The solenoids for the afterburner stage will not be staggered as far as activation and turn off. If it ends up, and I'm sure it will, that the nitrous gets to the nozzle before the fuel, that will only cause a lean spike at the start of the hit and hopefully the lean spike may help in lighting off the afterburner. Staggered activation is still planned as far as the primary nitrous stage coming on a split second before the afterburner stage.
There's an event at the track this weekend that I'm planning to make. I wasn't planning on testing the afterburner so soon, but since the parts came in so quickly,... maybe. :wink:
hungerbuhler1
Active Member
- Joined
- Dec 20, 2009
Good luck with this its very interesting and would love to see the results if you make it to track
When I was making exhaust back pressure checks with the new turbo, I had mounted a back pressure gauge in the exact same port that I plan on using for the afterburner nozzle. The back pressure gauge had a 1/8 npt male on one end of a rubber hose with the gauge on the other end.
I had that gauge and hose mounted for ages before I finally bothered to remove it. The rubber hose held up just fine after all that time. I would have to imagine that the materials I'm using for this afterburner will do fine with the heat also.
The adapter I used to mount the gauge hose had a 1/16" feed hole through it, so that flow was somewhat restricted from the exhaust pipe to the gauge and hose.
The jets that I will be using in the afterburner nozzle will have feed diameters considerably less than 1/16". More like .028" - .035" or so.
I think I'm going to use a 'lean best torque' n/f ratio with the nozzle to start out with.
I had that gauge and hose mounted for ages before I finally bothered to remove it. The rubber hose held up just fine after all that time. I would have to imagine that the materials I'm using for this afterburner will do fine with the heat also.
The adapter I used to mount the gauge hose had a 1/16" feed hole through it, so that flow was somewhat restricted from the exhaust pipe to the gauge and hose.
The jets that I will be using in the afterburner nozzle will have feed diameters considerably less than 1/16". More like .028" - .035" or so.
I think I'm going to use a 'lean best torque' n/f ratio with the nozzle to start out with.
Finished some testing at the track last night and no funky problems associated with the afterburner occurred. No explosions or melt downs. I still need to study the datalogs to see if the system helped with anything. As far as time slips, no new bests to report. Performance was not drastically off, though. Performance off by maybe hundredths of a second and 1 or 2 mph.
It's really tough to judge by the timeslips though, because the new system seemed to throw off some of the other timed systems throughout the run. For one, the boost control curve needs better dialing in to prevent some traction loss I was getting on the 1-2 shift on more than a couple of the passes.
During some quick checks of the datalog at the track, it appeared that the boost (turbine speed) in relation to the rpm was better, but it appeared the rpm climb was slower. It's as if a trade off was happening.
Was the afterburner helping increase turbine speed, but increasing backpressure and interfering with pressure pulse tuning?
It's a little early to trash the afterburner idea. There's a lot of dialing in to do with it first. Hit size and the afterburner n/f ratio are two very important variables to play with, now that we're sure I'm not going to blow the downpipe off of the turbine housing or melt down the turbine wheel.
It's really tough to judge by the timeslips though, because the new system seemed to throw off some of the other timed systems throughout the run. For one, the boost control curve needs better dialing in to prevent some traction loss I was getting on the 1-2 shift on more than a couple of the passes.
During some quick checks of the datalog at the track, it appeared that the boost (turbine speed) in relation to the rpm was better, but it appeared the rpm climb was slower. It's as if a trade off was happening.
Was the afterburner helping increase turbine speed, but increasing backpressure and interfering with pressure pulse tuning?
It's a little early to trash the afterburner idea. There's a lot of dialing in to do with it first. Hit size and the afterburner n/f ratio are two very important variables to play with, now that we're sure I'm not going to blow the downpipe off of the turbine housing or melt down the turbine wheel.
After studying the datalogs, things look very promising. Not one of the passes were really clean. A lot of pedaling on my part due to traction issues, and a lot of mis-timing of the nitrous system shut off and the boost controller. And to still come out with performances that were only slightly off. This afterburner thing just might work. :biggrin:
For the first time, 103 kPa accomplished by 4200 rpm, where as before 103 would come in at closer to 4600 rpm. The small amount of boost that started in at 4200 rpm didn't maintain climb. The boost climb faultered and then came back at 4600 rpm. Most likely a sign that I need to work on the fuel map in the 103-106 kPa section between 4100-4650 rpm to help keep the ALS fired off. A little leaning in that section is probably called for. If I can get the boost climb to stick starting out at 4100 rpm, that would simply be amazing considering the size of this turbine side.
The shot size of the afterburner last night was only 28 hp. Next time out, we'll be upping that size to a 50 shot.
For the first time, 103 kPa accomplished by 4200 rpm, where as before 103 would come in at closer to 4600 rpm. The small amount of boost that started in at 4200 rpm didn't maintain climb. The boost climb faultered and then came back at 4600 rpm. Most likely a sign that I need to work on the fuel map in the 103-106 kPa section between 4100-4650 rpm to help keep the ALS fired off. A little leaning in that section is probably called for. If I can get the boost climb to stick starting out at 4100 rpm, that would simply be amazing considering the size of this turbine side.
The shot size of the afterburner last night was only 28 hp. Next time out, we'll be upping that size to a 50 shot.
In reviewing some video of the night runs, I noticed that on the hit of the nitrous at the line, I could hear tinking noises coming from the car. It sounded like loud detonation. I wonder if that was the afterburner. Maybe the ignition of the afterburner is not as smooth as I hoped. Maybe mixture collects, then ignites, collects, then ignites. Just like a gasoline ALS. I'm sure the reason it only sounded like tinking is because the shot size was only a 28, not a whole cylinder full of mixture. I wonder what the 50 shot is going to sound like.
