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+--- Thread: How to build VNT manual controller for Gas car (/showthread.php?tid=1411)
How to build VNT manual controller for Gas car - alecuba16 - 06-03-2010
Hello!
I'm alex, i'm from spain and i'm very interested of variable turbos, is nice improvement of a normal turbo.
I have two VNT turbos to test on my GAS car, but i must find first a mechanical controller, then i will build a electronic analog by servo pwm generated by LM555 and potentiometer (potentiometer is the map resistor based sensor) controller.
Then i have now a GT2559V, this is vacuum controlled, is from saab 3.0 i think, and i plan to put on a full forged internals 1.6L engine doing 10-12psi is very good pressure for gas engine and try to not burn the turbo vanes.
Then i think that i must use a vacuum controller connected to intake manifold, and then a secondary pressure actuator (like the normal wastegates) connected in parallel with a spring to put the blades full opened when the pressure arrive to maxium that i will control.
Auxiliary i will use a external wastegate to prevent if the vanes doesn't moves and get a loot boost it will open for example at 14psi to avoid problems.
This is the first controller that i want to test.
Then i got another GT2250V i think for 2009 Murano dci 190hp, this is servo controlled that i can use a pwm signal from LM555 and a map sensor input actuating as potentiometer that set the Pulse width, to put more closed o opened vanes, previously i will set the full closed and full opened by using the TPS sensor (fully opened vanes when the TPS is restrain position) and fully closed vanes when TPS is at maximum, then in parallel i will connect another potentiometer actuating as MAP(manifold pressure resistor based) to do the self regulation from closed vanes to fully open when maximum boost is got, the maximum boost i will another in car potentiometer in serie with the map sensor to set the maximum.
Then when i'm on idle the vanes are fully opened because the TPS potentiometer are in fully opened position (idle) and the MAP are on (- pressure).
I have a electronic Potentiometer TPS on my engine.
When i press the thorttle the TPS will get pass some current and this will change the PWM of LM555 and will close a little the turbo vanes and the MAP if i set to 12psi and go 5...6...7....10... 12 psi it will give pass to the necessary current to open the vanes again because maximum boost is got, then in freeway the TPS will control the turbo vanes , if are 30% of tps -> 30% of turbo vanes closed, and if got the maxium boost it will open to not boost more , because is not needed.
If i go full thorttle the TPS will go 100% and the vanes will close to do a little turbo , it will spool very fast and when get the maximum pressure (12psi in the example) the map will send the necessary current to do the PW to open fully the vanes and the turbo will open or close the vanes based on MAP sensor.
Thanks for read my post and sorry by the mistakes.
Can you advise me?
RE: How to build VNT manual controller for Gas car - ForcedInduction - 06-03-2010
Get an actuator from a Shelby CSX. It has vacuum and pressure ports so manifold vacuum can open the vanes and it will control like a wastegate with boost.
Or you could run a system the same as mine operated by vacuum and controlled by boost, but you'll need a good size vacuum reservoir since you don't have a constant vacuum source.
RE: How to build VNT manual controller for Gas car - tomnik - 06-03-2010
the higher exhaust temperatures on gassers compared to diesels will kill the VTG.
The one and only gasser with VTG is Porsche, but they use different material.
Tom
RE: How to build VNT manual controller for Gas car - alecuba16 - 06-03-2010
There are so many people with holset ve35 VTG turbo runing on 600whp+ Gas cars like eclipses, B20 honda Crx, and another cars
.I know that the garret system are rotary vanes versus the holset that is sliding surface of fixed vanes.
The holset are more stronger and can hold more EGT's than the rotary system of the garret.
Anyway i didn't pay for the turbos, one friend that works on nissan give me the new, because they will destroy by overstock on the testing department, and the used was from friend crashed SAAB 9-5 3.0 (GT2559V)
My objective is only play with they because maybe in the future i will run a holset ve35 on my 1.6L.
thanks
RE: How to build VNT manual controller for Gas car - alecuba16 - 06-04-2010
Hello again,
What about to use a intake cruise control actuator? they have both input (vacuum on top and presure on side)??
This will work as manual control?