External wastegate question?


May 22, 2012
We have been running internal wastegates on my tt forever.Since we bracket race in the no-electronics class,the track gave the ok to run electronic boost controller/electronic boost gauge and 2-step if i so choose.My question is, can the external wastegate be preset at low boost{3,4,5lbs) for launch?and then about 22-23 lbs at wot? Also will i have to change downpipe,{hate that dame THDP anyway}.
There probably are different ways to accomplish what you stated?

With my boost controller and 2 step, my launch boost is determined by my 2 step RPM.

If I leave at 3500 the boost is ~6-7 psi and very quickly ramps to 22 psi and then drops to down-track target boost.

It took me about 2 race seasons to dial in the best combination, as all cars, drivers and tracks are different. :)
Takes some concentration controlling boost launch on foot but we've manage..just looking for more precised launches..any other way besides the 2-step?
msbc-1 can be programmed for launch and run using single or dual port waste-gates.
I purchased one used from another board member but haven't tried it out yet. However, I was impressed w/it's programming abilities. The latest programable bc's would be the ams-500/1000 series.
If you keep an eye on the parts-for-sale section, you maybe able to get a good deal. I think you just missed one on the ams-500.
I have one, but I think its missing the pressure sensor. I'll look for it if you are interested.

on the msbc-1 turbo 12G and H (also deeds et-o1) have timers for 5 stages + launch stage , ramping and is closed loop control using its own map sensor good to 60psi with the 12g , 80psi with the 12H /et-01.

you can set the launch boost and then move from that to a timed staged for your target boost , you will need a way to switch into launch mode and have it release when ready to go the timers let you set a boost out of the tree and lower or higher downtrack (assuming your ecu can adapt fuel for boost changes)
you can only target a launch as low as your spring , if you run a 9psi spring and target 6 on launch it wont stop there without a 2-step with a low rpm when on the two step it will hold rpm but can still build boost as you hold on it

install of msbc-1 can be run many ways but dual port manifold mode or dual port wastegate mode(best)
manifold mode (the msbc-1 map sensor connected to manifold ) allows you to put say 20psi on the controller and get 20 psi (provided your gate is sized enough to be capable of controlling it at 20) and it turns on and starts controlling at 3psi
you can run a lower psi spring (5-6) but when connected in manifold mode until you reach 3psi you are using just the spring to hold the gate shut , on a sharp stab as you would do bracket racing could pop open the gate, it wont build boost with gate opened and without boost the spring has no assist to close . mainifold mode works for most tooling around and slower spool setups but isnt the best as it tends to overshoot if you have quick spool , it will work its way to target but it isnt dead flat

msbc-1 can be used in wastegate mode (map sensor connected to top of gate ). wastegate uses the pressure on the top of the gate to regulate the boost , you need a switch to turn on wastegate mode and stay on while in boost , you could add a manual switch i use a low pressure hobbs set to 2psi , only thing to note is wastegate mode you need to add the spring to the boost number you select .. say you have a 6psi spring ..to get 20psi you will have to enter 14 on controller (it varies so you need to test on your setup). to launch at 7psi you would set launch at 1

for best launch with light spring you can add co2 (see summit for co2 kits) to the msbc-1 , once turned on (3psi manifold mode or a switch in wastegate mode) instead of using the manifold air to hold the gate closed you use co2 (about 35psi) . the controller applies c02 to top of the gate and even with a light spring you will have the added assist of the co2 to keep the gate closed and ensure the quickest spool
c02 makes the light spring work but if in manifold mode it still can overshoot

i run both msbc and bailey 2tep but prefer the way the boost controller holds since its not dropping cylinders
i use a tbrake and that switch activates the launch mode and the 2 step , with 4.5 spring co2 and plumbed in wastegate mode (uing a hobbs switch) the boost build is quick and holds steady (both rpm and boost ) the boost is dead on with no overshoot while spooling and no overshoot after launch.

downside to all this is the msbc-1 (deeds) is no longer being made and your only shot at getting one is used
you will need an external gate
the AMS 1000 works similar but is even better , just cost more
That sounds impressive to me! I purchased mine as an experiment to better control the int. gate on my new rjc 5/4" d/p, as I sold my atr d/p w/the ext. gate.
You know the ISAC isn't bad for boost control either. Not currently sold but I hear Shane might have one.
If you keep an eye on the parts-for-sale section, you maybe able to get a good deal. I think you just missed one on the ams-500.

The AMS 500 is readily available and very easy to use. Like pacecarta posted, for consistancy on the launch you must run a wastgate spring rated lower than your launch boost
pacecarta are you running an internal wastegate or do i need an external wastegate with msbc or ams500? 'cause i have to keep this killa as close to no-electronics as possible{lotsa crybabies in this class}.
the majority as well as pacecarta are probably running external wastegates, which is a better choice for controlling boost.
ISAC it's worth it for the 'Quick spool" mode alone. It's a better thrill ride than a coaster
All the info is greatly appreciated guys. will get to work on this.May even get to see some of you guys at Reynolds...and hey thanks alot guys..Will check with Gbody...