MCleod RST, RXT clutch

[s8v4o]

DiMora uses one.

So do I.

I have been warned not to bounce off the rev limiter in these cars.

When I used to race imports, I bounced all day off the rev limiter and never had issues.

But it seems like these cars (Mustangs) its not recommended. Hopefully someone can explain why the difference. I think its the way Ford has the limiter setup vs how imports do it.

Ford cuts fuel, others cut spark. The WOTBOX also cuts spark with it's rev-limiter. Cutting spark is generally safer than cutting fuel.

 

[Dubstep Shep]

Question here.

Cutting fuel in a direct injection vehicle shouldn't effect anything, correct? The only reason that it's bad is because some fuel gets into the cylinder, but it's really, really lean, right? If NO fuel got in, there wouldn't be any combustion. Or is that not quite right?

Also, if the fuel isn't burned because spark is pulled, is that going to effect your AFR?

 

[s8v4o]

Question here.

Cutting fuel in a direct injection vehicle shouldn't effect anything, correct? The only reason that it's bad is because some fuel gets into the cylinder, but it's really, really lean, right? If NO fuel got in, there wouldn't be any combustion. Or is that not quite right?

Also, if the fuel isn't burned because spark is pulled, is that going to effect your AFR?

In theory if absolutely no fuel gets in then it should be ok. With cutting spark though typically the unburt fuel will ignite in the exhaust. That's how/why turbo guys use the 2 step to build boost off the line. The AFR will be off. More than likely you'll get a false lean condition because unburt oxygen is passing the O2 sensor. Some of the mixture will burn in the exhaust but probably not all of.

 

[Dubstep Shep]

In theory if absolutely no fuel gets in then it should be ok. With cutting spark though typically the unburt fuel will ignite in the exhaust. That's how/why turbo guys use the 2 step to build boost off the line. The AFR will be off. More than likely you'll get a false lean condition because unburt oxygen is passing the O2 sensor. Some of the mixture will burn in the exhaust but probably not all of.

Interesting. So pulling spark could cause a lean condition. I suppose that wouldn't matter in closed loop though would it?

 

[s8v4o]

Interesting. So pulling spark could cause a lean condition. I suppose that wouldn't matter in closed loop though would it?

It's a false lean, not legitimately lean. It's just how the O2 interprets what's going on. Kinda like if a vehicle is running so rich that it misses. The unburnt mixture fools the O2 sensor into a false lean condition.

Open loop is where it shouldn't matter. Closed loop the computer is always making changes.

 

[Dubstep Shep]

It's a false lean, not legitimately lean. It's just how the O2 interprets what's going on. Kinda like if a vehicle is running so rich that it misses. The unburnt mixture fools the O2 sensor into a false lean condition.

Open loop is where it shouldn't matter. Closed loop the computer is always making changes.

Uh, I thought in a state system open loop was where the loop was "open" to new data, whereas closed loop was when the loop was "closed" to the data. I could be wrong.

Either way, when the engine is WOT the O2 sensors don't matter so the false lean wouldn't mess with anything but datalogging

 

[BruceH]

So do I.



Ford cuts fuel, others cut spark. The WOTBOX also cuts spark with it's rev-limiter. Cutting spark is generally safer than cutting fuel.

I'm pretty sure that both fuel and spark are cut but can't find a source. Do you have anyplace we could read about the Spanish oak rev limiter?

 

[s8v4o]

Uh, I thought in a state system open loop was where the loop was "open" to new data, whereas closed loop was when the loop was "closed" to the data. I could be wrong.

Either way, when the engine is WOT the O2 sensors don't matter so the false lean wouldn't mess with anything but datalogging

Closed and Open loop. http://www.enginebasics.com/EFI%20Tuning/Closed%20Loop%20o2.html

Also while the 2010 and older cars go open loop at WOT the 2011 and up do not. They are always adjusting so I'm not really sure how the new 5.0's computer interprets the 2 step.

I'm pretty sure that both fuel and spark are cut but can't find a source. Do you have anyplace we could read about the Spanish oak rev limiter?

Bruce, I don't have any concrete info but I was just regurgitating information that I've read on this site. Let me do some searching and see what info I can find.

 

[warbird]

You might be the first person not to like the McLeod clutches...hmm

No...he would have to get in line.