It is a 2 Step Rev Limiter. It builds 5-7 psi out of the hole. It cuts out fuel on one of the cylinders when compressing. It makes the turbo build boost without load on the front tires.brian said:what does this do exactally? retard timing, control boost?? I have seen this before but not sure the mechanics of it.
You are partially correct.Saaby said:Wouldn't that cylinder run super lean!? I don't understand...that sounds like it would lead to detonation.
You hit the nail on the head! I bet you are an Engineer Major, huh?!?!?spdracerUT said:It can't run super lean if there's no fuel at all! Remember, detonation is when the fuel preignites, or the flame propagation isn't smooth, etc. You get the idea.
But if there's no fuel, there's nothing to detonate. From what I can tell of how the drag launch program works.... well, in order to get the turbo to spool up, the engine has to be loaded in order to flow enough exhaust gases to spool the turbo right?
So what they're doing is cutting fuel to one of the cylinders and basically turning that one cylinder into an air pump. There's now a load on the engine caused by the compressing of the air in that cylinder. That load is enough to get that turbo to spool.
Man, that's badass, I've never thought of that before.... whoever came up with that idea is a genious.
to spin the turbine on the turbo. air (whether exhaust or pumped air from the dead cylinder in this case) passes through a the exhaust housing on the turbo, which in turn spins the compressor, which forcefeeds the motor.Now, there is still one thing that baffles me. WHY does there have to be a load on the pistons to spool the turbo
yes, this is why the motor only builds 6-7 psi while on the 2 step, as opposed to the up to 20+ psi that many turbo cars are capable of.I assume that for the turbo to spool faster, the gases have to be hotter and/or faster moving, right?
Yeah, graduate in May in Mech. Eng. Anywayz, think of it this way. The higher the load on the engine, the more effort/power it puts out; i.e. the more air and fuel goes through the motor which leads to more air thru the turbo which gets it to spool. If you just sit in neutral and rev the motor, there's no load, so not that much fuel or air is going to go thru and the turbo won't spool.Saaby said:This is great. Thanks for the pearls guys. Now, there is still one thing that baffles me. WHY does there have to be a load on the pistons to spool the turbo. What difference does that make on the gases that are pushed out of the cylinder on the exhaust cycle of the cylinder to make the turbo spool faster? I assume that for the turbo to spool faster, the gases have to be hotter and/or faster moving, right? Well then I just don't see how the gases could become hotter and/or faster if there is load on the cylinder...
my question is: can this be programmed into a JWT ECU or do you just buy the unit? what comnpany makes this unit that cuts the fuel?
also, on a T28 which is only boosting like 9-10 psi max, do you think it would still build 6-7 psi on the 2 step? that would be really cool, no turbo lag out of the hole!
yeah, i figured you would need the nitrous module, because it can control fuel and all that other good stuff based on throttle position, etc. does the program work where it sees that the clutch pedal is depressed (not sad) and cuts fuel to a cylinder?The "Drag Launch Program" is offered only by JWT. You will have to purchase a Nitrous Module to run the Drag Launch Program.
Bro, you are way off. Please do more research.CharlieH98 said:Ah what the hell I'll throw my $.02 here.
The turbo will create boost (spool) with or without load. The engine just has to be running above a certain rpm that creates enough exhaust flow to spin the turbine fast enough to make boost. On small turbos, anything over 3500rpm will spool the turbo. Load on the engine has nothing to do with the turbine "spooling".
JWT's trick is to fool the bypass valve or BOV into closing by sending it a low vac reading. This allows the engine to run boosted without actually having a load on it.
Ok now it's simple to figure that you could create the same condition by temporarily removing the signal to the bypasss valve/BOV with your left over EGR selenoid and a switch.
For a rev limiter: the cruise control comes to mind. Ever have it on cruise and take it out of gear without the clutch? With a little effort you may be able to use the cruise control as a rpm switch.
Take it for what is worth.