AMS1000 operation for dummies

[Alky V6]

Donnie,
In my situation I want to use a boost controller for just that controlling boost. If I want 25 psi and I program it to run 25 psi that is what I want it to do. The boost spike on the initial ramp up is something you will see no matter what controller you use and IMO tuning it out by slowing down the turbine will affect ET greater than killing timing to compensate for it. There are several ways to skin a cat this is just the way I see it and what I think'll work. I would rather overshoot and come back down than slow it down to reach peak boost levels. Again, I am still messing with the idea and only started when going to the drag radials. With slicks the boost spike was never an issue and I never ramped it in either. The only problem I saw with the spike was the crazy things it did to fueling trying to keep the WBO2 correction on which would cause swings in AFR well into 2nd gear.

I don't think the amount of boost you run or the power you make should make a difference in the discussion. A 2 psi spike in first gear shouldn't hurt anything in the motor as it isn't under a significant load at that point so I don't see how that should make a difference.

Sam,
You are still killing power whether you lower launch boost, open the WG, kill timing etc you are still killing power to keep the nose down and your not accelerating the car and probably leaving some ET on the table. Also, that boost spike is likely occurring half to a full second into the 60' so your car is probably well into the air at that point.

If my car saw 8 inches of air under the tires Friday that would've been a lot. I'm waiting to see the pic on Milan's website when they get them up. I saw the flash so I'm pretty sure they took one.

I agree if you are going to use the boost controller as a traction/wheelie device the AMS is a MUCH better at it than the MSBC. Like I said I just want it to control a steady boost level I program it for and the MSBC does that just fine.

Good discussion BTW.

Post a link if your car comes up on that site. I'd like to see it.

I understand you Chris. You've discovered a overall tune that works for you. That's great.
For the rest of us that are wondering how we would solve a spike like that using the ams unit, I'm going to take a stab at it. Bear in mind, I am a ripening rookie with this unit, so be gentle with me Cal.

Let's say I want a very quick ramp up to a target boost of 25 and I'm getting a spike of 3 psi over the target for a duration of .15 seconds. I would cut the first stage very short and target a boost value 3 psi below the real target of 25. The next stage would be my true target of 25 psi. The duration of the first stage may require fine tuning in both time duration and target, but it seems to me that would take care of the boost spike and give you a quick smooth rise to your target of 25 psi. In essence, you are still getting the 3 psi spike at the end of the first stage, but since you've put the first stage target 3 psi under your true target of 25, the spike ends up being at your true target of 25 psi. The second stage then quickly takes over at the peak of the spike and you have your stable boost level of 25 psi. There. How'd I do?

I completely understand that the target numbers programmed into the unit would not really be the real boost target numbers, but would be the control pressure numbers that would 'net' me the desired boost numbers.

 

[Alky V6]

Boost spikes on initial spool up is not necessarily a bad thing. For instance, if you have an engine that can ultimately handle 40+ psi of boost by the top end of the track, and the chassis/tires will only allow a 25-30 psi boost level at around the 60 foot mark, and the boost controller is set to a 25-30 psi level until sometime after the 60' mark, then a 2 to 3 psi spike can be safely tolerated, unless the spike causes a loss of traction.

QUOTE]

For me it did not cause a loss of traction it caused the car to Head up toward the sky instead of down the track.

When it would do a big wheelie I knew when I looked at the log the target boost was going to be over shot!! The travel limiters helped but with the instant center of gravity where it was to get maximum traction There was nothing I could when the car decided to throw more horsepower at the rear wheels than I anticipated. It just got frustating trying to out guess the boost controller. The problem was the MSBC 1 was not consistant


The big wheelies actually slow the car down. Like you said. The main goal is to keep accelerating forward down the track as fast as possible. This issue is now gone with the AMS 1000!

Sam. If you have any vids of your launch, post a link. We need some examples. That goes for anyone else, for that matter.

 

[lazaris]

One way to help spiking is wasgate capacity/size. If your looking to control that use the largest one you can.

 

[Alky V6]

Very good point.

 

[Sam Colalillo]

Sam. If you have any vids of your launch, post a link. We need some examples. That goes for anyone else, for that matter.

Don,
I only know of one video of our car on the net with the AMS 1000.

It is about 2 minutes and 48 seconds into this video.

Norwalk 9.415 @ 144

I am still running the big innovative pro gate. It is plumbed out of the header then to the down pipe. Completely by passing the turbo.

No more comments fom me, Im just gonna sit back and listen.

 

[Alky V6]

Sam. Fix the link first before you get comfortable. Yeah!

 

[Chevota]

AMS 500 launch..

Sorry not a GN, but 1 of 2 passes with the 231ci and AMS. 1st stage 30psi. 2nd stage&gear 35psi.

YouTube - Irwindale wheelie 5.54@128



















Random shop pic of the day -

 

[Alky V6]

I like the nuclear resistant pins.

Turbocharged Pro Mod?

 

[Chevota]

I like the nuclear resistant pins.

Turbocharged Pro Mod?

Define "Pro Mod" :biggrin: Like 300M?:wink:

 

[Chevota]

Apologize for getting "off topic". Pics of shiny motor pics distract me Back to the AMS 1000!

 

[Alky V6]

I still want to discuss traction control through a shift point and using the 'aux' channel to control the BOV.

Traction can be a problem during a shift, especially when a tight T/C is being used. The large rpm drop and sometimes resulting boost spike at the shift can be enough to overpower the level of traction at the moment. Some ECMs have a feature that allows the tuner to cut back ign timing if wheel speed gets out of hand. I don't have any experience with this type of feature, but it sounds very interesting. The manifold boost level could be controlled during the shift to accomplish the same thing by programming a short spike of boost loss during the shift. The amount of boost loss, duration of the spike, and how quickly the boost recovers or is ramped back in would have to be tailored to the individual situation.

 

[Alky V6]

BOV contol using the 'aux' channel

This idea has got my interest up. The 'aux' channel of the ams1000 can be employed to monitor another pressure, or control another pressure operated device.

The 'aux' timer stages are activated at the same time as the main, or boost channel. This can make for some very interesting configurations.

Let's use my situation, using a 3 amber tree.
The transbrake button is pressed, sets the transbrake, and powers up and arms a 5 channel delay box and puts the ams1000 into launch control mode.
Throttle is at WOT and the T/C stall limits rpm to 2440.
Boost launch control pressure set to net a conservative 8 psi boost level (to be raised in the future as needed or allowed).
Aux launch control pressure set to 0 psi keeping the BOV shut for the moment. The aux control pressure being routed to below the BOV diaphragm.

The transbrake button is released at the first sign of the first amber.
The aux channel immediately goes to a high enough set pressure to open the BOV completely.
At .380 second (or sooner) after button release the nitrous is activated. This allows a T/C stall increase to around 3400 rpm and a massive increase in exhaust mass flow to the turbine wheel. With the compressor wheel free to rotate without pressure buildup working against it, turbine and compressor wheel speed will increase at a faster rate than would be possible if the BOV were shut and the compressor wheel had to gain speed working against a building back pressure. The time that the BOV is shut will depend on how quickly the compressor wheel can gain speed and would have to be timed through trial and error. Hopefully, not too much error.
At the .980 second mark since the release of the T/B button, the transbrake releases. Whether the BOV is still open or not would depend on how much compressor wheel speed we have at this point.
Finally, the BOV is shut. It will be important to time this correctly so that there isn't a massive yank to the car that might upset the chassis/suspension.
The nitrous continues for a time period sufficient enough to reach a certain boost target for shutdown of the nitrous and allow the turbo to take over. Most likely, around 8 psi or a little more. That to be determined through trial and error.

The ramp rate for the boost channel would most likely be set to be as steep as possible, since I'm sure I won't have too much trouble with the 91mm boosting up too quickly. If I have a spike at the boost target during this preliminary stage of the pass, the engine can handle it.

 

[Dusty Bradford]

I still want to discuss traction control through a shift point and using the 'aux' channel to control the BOV.

Traction can be a problem during a shift, especially when a tight T/C is being used. The large rpm drop and sometimes resulting boost spike at the shift can be enough to overpower the level of traction at the moment. Some ECMs have a feature that allows the tuner to cut back ign timing if wheel speed gets out of hand. I don't have any experience with this type of feature, but it sounds very interesting. The manifold boost level could be controlled during the shift to accomplish the same thing by programming a short spike of boost loss during the shift. The amount of boost loss, duration of the spike, and how quickly the boost recovers or is ramped back in would have to be tailored to the individual situation.

For cars that hit the tires too hard during the gear change. I use a gear retard feature in the MSD 7531. I will gradually pull 2-4* of timing right before the gear change, then gradually put it back in after the gear change.

I have also never saw a boost spike on any AMS equipped race car. Proper gate size is the key. I'm sure throwing n2o into the equation may cause this but it would become a tuning issue of the right turn-off point for the n2o and the right co2 pressure and ramp at that point.

 

[Alky V6]

I would agree.

 

[Alky V6]

Is 1/8 ID supply line adequate enough from bottle to solenoids near the w/g?

 

[Robert Wilson]

Is 1/8 ID supply line adequate enough from bottle to solenoids near the w/g?

I am using 1/4 OD tubing but I am sure with the small volume of CO2 used that 1/8 would be fine.

 

[Dusty Bradford]

Yes. 1/8 is plenty. Like he mentioned. It's such a small volume to fill, the small line works just fine.

Another thing I do that some don't. I use n2o rather than co2. I found it's very difficult to get the bottle full with co2 as your just equalizing pressure. No one locally has a pump that can transfer liquid co2 to my 10oz bottle. My friend has scales and an n2o pump so I fill it with 10 oz of liquid and can race all year on 3 bottles. Probably 30-35 passes on 1 bottle. I found that equalizing the co2 only got me 2 oz's of liquid.

The biggest thing you have to watch is the condition of the gate's diaphragm. If it leaks, you can backfill your intake with n2o and when you start the car............boom. I always close the bottle valve when in the pits.

 

[Alky V6]

Your source CO2 cylinder needs to be a siphon cylinder to fill your empty cylinder efficiently with liquid CO2, or if the source bottle is not a siphon bottle, you can turn the source bottle upside down so that liquid comes from the valve. Only fill your empty cylinder up to the certified weight for that cylinder. 2.5 lbs of liquid CO2 for a 2.5 lb cylinder.
Very similar to how you fill a nitrous cylinder.

Does the 'freeze the cylinder' trick work with CO2 like it does with nitrous to help get more liquid in the cylinder?

 

[Chevota]

Does the 'freeze the cylinder' trick work with CO2 like it does with nitrous to help get more liquid in the cylinder?

Yes, but keep in mind the pressure increases in relation to heat just like n2o and the safety burst disc is usually rated at 1100-1200psi. Be cautious on a hot day. =)

 

[charlief1]

Freezing the cylinder works on quite a few different things Donnie. I've used it with A/C for recharge cylinders so it should help with CO2 as well. If you can pull a vac on the cylinder before you freeze it to help it suck more into the cylinder. I forgot to add the part about the "safety valve" though. My bad.