"Spooling wastegate" question for AMS-1000 users

[Scotts87LX]

I was reading another thread on using a wastegate to aid spooling and I've seen this done for many years. I think Jim Monson's car was the first I ever saw with this set up, but I have no idea how Jim controlled his. I'm very interested in trying this on my 275 car after reading Sebastian's post:

Originally Posted by control freak

You can place a small gate on the charge pipe and use a solenoid to apply air to the bottom port which will open it. When the car leaves the solenoid closes and removes air from the bottom port closing the gate. manifold pressure is directed to the top keeping the gate closed thru the run.

If you have an ams-1000 you can use the aux channel to do this but with even more control as you can control how long it takes for the gate to close/open.

I'm not familiar with how to do this. I'm currently using the AUX channel on my AMS to log actual manifold pressure, but I'm not opposed to using it to a control a gate if it would help me spool instantly. Has anyone tried this with the AMS controlling the gate on the inlet pipe? and if so, how do you set it up and how does it work? I'm concerned about damaging the turbo if the gate slams shut too quickly, not to mention blowing the tires off (275 radial car). Oh yea, and there's that over spinning the turbo thingy too (BOOM!). It sounds to me like the AMS could give some really finite control over the closing rate of the gate. Although I've not actually tried a wastegate on the inlet pipe before, I would think it wouldn't take much of a leak at all to get the turbo wheel really "winging," so I'm guessing a fairly tiny wastegate would be all you would need. Is that a correct assumption?

Sebastian, could/would you elaborate on this? Or anyone else who is running an AMS to control this?

It sounds like there is a balancing act between the pressure you set the AMS to (the co2 pressure on the bottom of the gate to get it to open), and the actual boost you are generating in the intake manifold (the pressure applied to the top of the gate). I'm just having difficulty understanding how you go about preventing a HUGE boost spike when the gate closes. How do you make the transition smooth? Is the gate only open while you are on the foot brake and then closes when you hit the trans brake? If so, can the boost stabilize at your launch target number quickly enough to keep from blowing the tires off when you release the brake?

This deal sounds like the ultimate "best of both worlds" deal for guys with small cube engines with bigger turbos and really tight converters (like me lol). It sounds like it has tremendous merit, but I would love some more definitive info on it before I start spending money trying it.

[b00sted]

Not sure if he's on here, but DaveH was just testing this out. http://www.youtube.com/watch?v=k8HaVgWrda4

It'll be interesting to see how it works at the track, as he has the definition of a big turbo/small cubes setup.

[t tops]

Sounds interesting

[Djstorm100]

In to know.

[tirefryin_s10]

Interesting.

[turbo]

subscribing

[Jim Monson]

I used to use a waste gate on the boost tube to control launch boost. The ASM1000 has eliminated the need for this gate. I just have a blow off valve now. The AMS1000 controls everything. It gives me much more control than the old way.

My old setup was simple. I had a switching valve wired to my trans brake activation. Normally, manifold pressure would go to the top of the gate. No pressure went to the bottom. During the run I had manifold+spring pressure to keep the gate closed. When I lifted and the engine went into vaccum, the gate would blow open (blow off valve).

At launch I would hit the trans brake activating the switching valve. The pressure would exhaust on the top of the gate and be routed to the bottom of the gate. In that case I had only spring pressure holding the gate closed. I had my spring set at 10lb. Any manifold pressure over that and the gate would open and hold steady. When I released the brake the pressure on the bottom would exhaust and go back to the top of the gate.

[Scotts87LX]

Thanks for the quick response Jim. The AMS gives me extremely accurate control over boost going down the track, I'm just looking for a way to bring the engine up on boost more quickly when staging. I have a Chance converter and as I'm sure everyone with a turbo car seems to know, it's really tight. I've had it back to Marty a couple of times and spend over $3K on it and I just can't seem to get a tune that will bring this converter up on boost in less than 5-6 seconds. I've gone from a stage 4 stator to a stage 5 billet stator, and I've played with the stator to turbine spacing and I'm still fighting this issue.

I tried a TCI converter John Kolivas loaned me. Actually it was Jeff Reid's converter out of his car, and the thing spooled GREAT! so I know the problem is much more converter than tuning. Anyway, I'm too deeply invested in this Chance converter to even think about selling it and I'm too poor to be able to just go out and buy another $2K+ converter. The slip percentage on the Chance converter is about 18% through the lights on the top end in the 1/8th mile. That seems high to me, but Marty says a spragless will always have a better slip % than his, but his will out MPH and ET a spragless. He said, she said? I don't know who to believe, I just need the car spool quicker and leave harder.
I'll wind up buying another converter before it's over and be lucky to get half what I've got in this Chance back out of it.

[Swampdonkey]

That seems like it would throw a huge amount of thrust load onto the turbo.

[2stroke]

if I understand...

you are using the wastegate to bleed off the intake manifold pressure so that the turbo has less restriction to spin quicker?

[control freak]

you can use a wastegate with no spring in it. Use control pressure to the to part of the gate. In launch program 0 . Then set your timers up for how many stages and what kind of ramps you want. For instance you could set up a single stage with 0 in the timer, 0 ramp and a target of 40 psi. So whne your on the transbrake there will be zero pressure on top of the gate. The gate will blow open as there is no spring in it. The second you release the brake the controller will apply 40 psi to the top closing the gate...this is where you will get your boost spike. If you gradually close it youll get a smoother hit.

[95mmRenegade]

Sent PM. A tight converter generally will bring the boost in faster. A loose converter does not guarantee the boost will come in faster, you'll get to your 2 step quicker, staging boost is still a function of time/load/heat. Real world data, old converter was 2.6 seconds to go 1.8 to 4.8# of boost with my old converter, new converter is tighter takes 2.3 seconds for the same range.

[Swampdonkey]

Originally Posted by control freak

you can use a wastegate with no spring in it. Use control pressure to the to part of the gate. In launch program 0 . Then set your timers up for how many stages and what kind of ramps you want. For instance you could set up a single stage with 0 in the timer, 0 ramp and a target of 40 psi. So whne your on the transbrake there will be zero pressure on top of the gate. The gate will blow open as there is no spring in it. The second you release the brake the controller will apply 40 psi to the top closing the gate...this is where you will get your boost spike. If you gradually close it youll get a smoother hit.

This seems like the only safe way to do it. Without being extra hard on parts, I'd have to say this would be a last resort.

[control freak]

if your set up is right you should not need to do this to build boost. BUT..sometimes you gotta do what you need to !

[Jim Monson]

Seb is right about not needing a spring. Some guys run without a spring and some use a very light spring. Either way, there's no need for the inlet waste gate with the AMS1000.

I have an old assed Chance converter in my car. It was built before they had all of these fancy stages on the stators. Hutch seems to have found a way to make it work. Mine slips about 11% at the top end of the track (1/4 mile). When the diode takes a shit it slips about 12-13%. I think it is basically a spragless converter when the diode locks up???