I envision the AMS coming in handy to precisely control the spool valve. Tee off the bypass valve input and kill two birds with one stone:wink:
BTW- Give me a call when you have a chance Don. I'd like to get your input on my fuel strategy.
Advancement of fuel delivery?
- Thread starter Alky V6
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I envision the AMS coming in handy to precisely control the spool valve. Tee off the bypass valve input and kill two birds with one stone:wink:
BTW- Give me a call when you have a chance Don. I'd like to get your input on my fuel strategy.
It's a possibility. Maybe I could work out something where the aux channel controls the BOV and the spool valve.
Yup. :tongue:Simple. Under pressure one opens and one closes and vice versa
Link to the quick spool valve project. http://www.turbobuick.com/forums/fa...urbine-housing-flapper-valve-need-help-2.html
The spool valve is finished, installed and the operation tested.
The aux channel pressure line to the BOV has been Tee'd into to supply pressure to both the BOV and the spool valve. Aux channel pressure has been programmed to 34 psi for launch and will time out 1 second after transbrake release. 32 psi is required to fully stroke and close the spool valve.
Having no clue how much quicker the turbo may spool, one person has suggested a 33% decrease in spool-up time, the nitrous shut down point will be the same 1 second after transbrake release. The on-time for each can independently be extended from there, after having some data to study.
The boost controller is set to ramp up from 0 psi to 18 psi control pressure by the 2.5 second mark after launch. Wastegate static spring pressure is around 8.5 psi.
Exhaust back pressure reading coming soon.
The aux channel pressure line to the BOV has been Tee'd into to supply pressure to both the BOV and the spool valve. Aux channel pressure has been programmed to 34 psi for launch and will time out 1 second after transbrake release. 32 psi is required to fully stroke and close the spool valve.
Having no clue how much quicker the turbo may spool, one person has suggested a 33% decrease in spool-up time, the nitrous shut down point will be the same 1 second after transbrake release. The on-time for each can independently be extended from there, after having some data to study.
The boost controller is set to ramp up from 0 psi to 18 psi control pressure by the 2.5 second mark after launch. Wastegate static spring pressure is around 8.5 psi.
Exhaust back pressure reading coming soon.
Forgot to load the video camera, so I don't have any in-car vids, and no exhaust backpressure reading yet.
The wastegate did require a control pressure of 24psi to maintain a boost level of 285-295kPa with a 8.5lb wastegate spring setting.
The length of on-time for the nitrous system was 2.25 seconds including a pre-launch time span of .465 seconds. Turnoff point was at 6-8 psi boost. For the next testing session, the on-time for the nitrous will be increased to 2.38 seconds with the same pre-launch time setting.
The amount of nitrous retard has been moved to 15 degrees.
The best 60 foot with the spool valve was 1.55 this past weekend. This was with a rather lean, unsafe n/f mixture. After richening it up, the 60 foot moved to 1.63.
The launch had a steady pull to it throughout first gear. The boost controller setting worked out well giving max boost 2.5 seconds into the run.
Right after the 1-2 shift,... wow!
The wastegate did require a control pressure of 24psi to maintain a boost level of 285-295kPa with a 8.5lb wastegate spring setting.
The length of on-time for the nitrous system was 2.25 seconds including a pre-launch time span of .465 seconds. Turnoff point was at 6-8 psi boost. For the next testing session, the on-time for the nitrous will be increased to 2.38 seconds with the same pre-launch time setting.
The amount of nitrous retard has been moved to 15 degrees.
The best 60 foot with the spool valve was 1.55 this past weekend. This was with a rather lean, unsafe n/f mixture. After richening it up, the 60 foot moved to 1.63.
The launch had a steady pull to it throughout first gear. The boost controller setting worked out well giving max boost 2.5 seconds into the run.
Right after the 1-2 shift,... wow!
Correction to above post. The 1-2 shift occurred at 7,085rpm @ 173.5kPa. 3.66 seconds into the run (3.195 secs. from actual TB release).
Max boost (285kPa) was not obtained until halfway into 2nd gear, 4.86 seconds into the run.
The boost controller was set too short for the run and the wastegate let go .68 seconds before the end of the run. Boost dropped from 288kPa to 220kPa just before letting off the throttle, just before the finish line. The feeling was as if the engine was seizing. The car just layed down. Didn't feel like pushing all the way across the finish line before knowing what was causing this.
Still the car netted a 6.4x ET, 119mph. Not bad for a start.
Tuning notes.
On initial n2o hit, rpm rose from 2333@92.2 to 3286@91 in .34 seconds.
Time to stall on the nitrous: .80 seconds. 2333@92.2 to 3777@94.7. The a/f ratio was still too rich at 3600-3800rpm. Flat line 10.17:1.
Time from nitrous hit to transbrake release: .465 seconds. 2333@92.2 to 3475@93.5. Actually, a small sign of boost building at this point. 92.2 being 0 boost.
There was a bump in rpm/map rise: 4705@103.3 to 5336@123. Duration: .400 seconds. Time into the run to the start of this bump: 2.26 seconds. The boost valve/BOV strategy may have had something to do with this bump. I may want to close off the BOV sooner if this bump is being caused by the present strategy of having the BOV close as the boost valve opens. Boost is trying to build up between 3550 and 4000 rpm. With the BOV still open during this critical time, I could be losing out on something.
Special note. There is a section in the fuel map that is very dynamic at converter stall on the nitrous, between 3400 and 4100. This is where the turbo is first showing signs of boosting. The mixture goes from very rich when the rpm first reaches this section (3550@92-93kPa), then switches to very lean as the boost starts to come in good by 4000@100kPa. I'm talking about the mixture going from 10.17:1 to 14.64:1 immediately. Map and rpm breakpoints have been changed around to allow fine tuning of this region.
MAP breakpoints: 91, 95, 98, 100, 110.
RPM breakpoints: 3475, 3800, 4000.
Presently there is an injector pw span of 37% from 3475@91 to 4000@100, with the a/f ratio fluctuating wildly between those two points. This is still a preliminary tune, but feels real good with this spread. To obtain the quickest boost and rpm rise, this area is going to be critical. Finding the right a/f ratio will be most important. I already know that a very lean mixture will yield a good 60 foot. But, it's too risky for my liking. I'm going to search out a best rich mixture for the region.
Yes, there are large swings in the a/f mixture between just 2 kPa in this region. An O2 feedback would not be able to react correctly through something like this.
Max boost (285kPa) was not obtained until halfway into 2nd gear, 4.86 seconds into the run.
The boost controller was set too short for the run and the wastegate let go .68 seconds before the end of the run. Boost dropped from 288kPa to 220kPa just before letting off the throttle, just before the finish line. The feeling was as if the engine was seizing. The car just layed down. Didn't feel like pushing all the way across the finish line before knowing what was causing this.
Still the car netted a 6.4x ET, 119mph. Not bad for a start.
Tuning notes.
On initial n2o hit, rpm rose from 2333@92.2 to 3286@91 in .34 seconds.
Time to stall on the nitrous: .80 seconds. 2333@92.2 to 3777@94.7. The a/f ratio was still too rich at 3600-3800rpm. Flat line 10.17:1.
Time from nitrous hit to transbrake release: .465 seconds. 2333@92.2 to 3475@93.5. Actually, a small sign of boost building at this point. 92.2 being 0 boost.
There was a bump in rpm/map rise: 4705@103.3 to 5336@123. Duration: .400 seconds. Time into the run to the start of this bump: 2.26 seconds. The boost valve/BOV strategy may have had something to do with this bump. I may want to close off the BOV sooner if this bump is being caused by the present strategy of having the BOV close as the boost valve opens. Boost is trying to build up between 3550 and 4000 rpm. With the BOV still open during this critical time, I could be losing out on something.
Special note. There is a section in the fuel map that is very dynamic at converter stall on the nitrous, between 3400 and 4100. This is where the turbo is first showing signs of boosting. The mixture goes from very rich when the rpm first reaches this section (3550@92-93kPa), then switches to very lean as the boost starts to come in good by 4000@100kPa. I'm talking about the mixture going from 10.17:1 to 14.64:1 immediately. Map and rpm breakpoints have been changed around to allow fine tuning of this region.
MAP breakpoints: 91, 95, 98, 100, 110.
RPM breakpoints: 3475, 3800, 4000.
Presently there is an injector pw span of 37% from 3475@91 to 4000@100, with the a/f ratio fluctuating wildly between those two points. This is still a preliminary tune, but feels real good with this spread. To obtain the quickest boost and rpm rise, this area is going to be critical. Finding the right a/f ratio will be most important. I already know that a very lean mixture will yield a good 60 foot. But, it's too risky for my liking. I'm going to search out a best rich mixture for the region.
Yes, there are large swings in the a/f mixture between just 2 kPa in this region. An O2 feedback would not be able to react correctly through something like this.
No other changes, except for fuel map and boost controller settings. Chassis is still setup the way I initially set it up after all the major suspension changes. All the launches during this session of testing were flat and smooth. No surprises.
Cool. Did you get the alignment done the way we talked about yet? You need someone to video the launch from the side to see if it looks like everything is working right. If you can get the fuel issues and timing worked out your car should be a killer at the track.:biggrin:
I haven't touched the alignment yet. Thanks to Sixshooter, I now have a set of real slip plates to use when I get around to the alignment. Thanks Wayne.
I'll hold off on the video until I get the launch working better.
kPa to boost psi:
110.4kPa = 02 psi
116.5 = 03
124.3 = 04.5 This is where the nitrous shut down.:frown: I know. This needs to be on longer.
126.7 = 05 Voltage booster for the fuel pump is activated here. Setting is at max.
147.1 = 08 This is where aux fueling is first activated.
175.4 = 12 This is how much boost I had at the point of the 1-2 shift.:frown:
202.5 = 16 A backup pressure switch to shut off the nitrous system is here.
242.5 = 22
255.4 = 24
270.9 = 26
282.5 = 28 Boost was controlled to this level for these tests. Fuel delivery was good at this boost.
290.3 = 29
295.4 = 30
303.2 = 31
312.2 = 32
Controlling the BOV at the launch is going to be scrapped. It will remain shut during the launch.
A good target for the a/f ratio on the nitrous looks like 12.0 to 12.2:1. The steep climb in rpm/map rise rate between 103 to 123kPa was at a time when the a/f ratio was hovering between 12.0 to 12.2:1. The rise rate was killed when the a/f ratio went to the low 11s to one, and lower.
5 degrees of timing added into the base timing map throughout the nitrous region and nitrous retard now set to 14 degrees. This will give me 6 more degrees of timing on the nitrous and should net me 19 degrees advance by the end of the nitrous hit.
The plugs are showing no heat at all.
The plugs are showing no heat at all.
Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
- Messages
- 5,802
Should be a noticeable difference with the extra timing.
I just realized that 123kPa was the time that the nitrous shut down. That's why the rate of climb fell off. The target is to have the nitrous shut down between 8 psi and 16 psi.
I agree. I'm sure I'll see a pickup with the nitrous retard reduced.
I want to share an important tuning note. This last Friday night, during one of the testing runs, the car experienced a lean backfire on the nitrous. I was playing around with that tricky transition area in the fuel map that I mentioned above where the turbo is starting to spool. Around 3800/98kPa. A fellow club member that was spectating thought for sure that I had blown the engine. I don't have fender wells so the orange flame that developed under the hood from the backfire was visible to the spectators. It only lasted a moment. The engine continued to run and I cruised through the pass and back to the pits. My intake plenum blowoff valve saved me again!
The main point here is, if I had the more appropriate amount of timing going on during this adjusting period of the fueling through the nitrous region of the fuel map, I could have kicked a rod. When dealing with nitrous, back off the timing until you're sure you have the mixture safe. Then bring in the timing.
I feel fortunate that I finally figured out the dynamics of that transition area in the fuel map without having to blow an engine. I'll post an updated pic of the fuel map soon. The climb in fueling from 3480/91kPa to 3800/98kPa is amazing. It's a wall of fuel like I've never dealt with before. Obviously, as the turbo is spooling up during this particular spot in the fuel map, it's radically changing the crossover and reversion characteristics of the whole engine combination in a critical area of the fuel map. 3600 to 3800 rpm has always wanted a big dip in fueling in this map region, most likely due to the large cam I'm using and the manifold tuning. It is always encouraging when you have to throw more fuel at a region in the map. More fuel = more powahhh.
I want to share an important tuning note. This last Friday night, during one of the testing runs, the car experienced a lean backfire on the nitrous. I was playing around with that tricky transition area in the fuel map that I mentioned above where the turbo is starting to spool. Around 3800/98kPa. A fellow club member that was spectating thought for sure that I had blown the engine. I don't have fender wells so the orange flame that developed under the hood from the backfire was visible to the spectators. It only lasted a moment. The engine continued to run and I cruised through the pass and back to the pits. My intake plenum blowoff valve saved me again!
The main point here is, if I had the more appropriate amount of timing going on during this adjusting period of the fueling through the nitrous region of the fuel map, I could have kicked a rod. When dealing with nitrous, back off the timing until you're sure you have the mixture safe. Then bring in the timing.
I feel fortunate that I finally figured out the dynamics of that transition area in the fuel map without having to blow an engine. I'll post an updated pic of the fuel map soon. The climb in fueling from 3480/91kPa to 3800/98kPa is amazing. It's a wall of fuel like I've never dealt with before. Obviously, as the turbo is spooling up during this particular spot in the fuel map, it's radically changing the crossover and reversion characteristics of the whole engine combination in a critical area of the fuel map. 3600 to 3800 rpm has always wanted a big dip in fueling in this map region, most likely due to the large cam I'm using and the manifold tuning. It is always encouraging when you have to throw more fuel at a region in the map. More fuel = more powahhh.
New boost controller strategy.
http://www.turbobuick.com/forums/tu...-ams1000-operation-dummies-5.html#post2272507
http://www.turbobuick.com/forums/tu...-ams1000-operation-dummies-5.html#post2272507
I think the problem that you have is that the turbo is toooo big and the converter is toooooooo tight
Turbo too big? Nah.
Converter too tight? Just a tad.
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