The Lotus Cars Community banner

1 - 8 of 8 Posts

·
Registered
Joined
·
826 Posts
Discussion Starter #1 (Edited)
sorry for the thread title..I just wanted to see if someone could answer my question.....sorry for that.. :)

...so I've been following all these threads on SC and smaller pullies and this and that. Let me start by saying I am a computer animator, I have never written software....nor have I ever even seen a screen representing what it would like to work with Engine Management Software. That being said, I do work with a lot of software engineers, including my girlfriend.....and I think I'm a pretty smart guy.

I see a BUNCH of threads regarding AFM and how that is a big problem if you switch pullies. And that brings me to my question.

And I KNOW this is a hot topic, and I'm just a dip sh*t who is trying to learn..not start a thread about anyones tune or implementation is sucky or anything like that.

SOOooooo..maybe the answer is that the Engine Management software is limited in what it can do...etc...?

IF putting a smaller pully on an SC will "eventually" lean out the mixture to the point of engine damage, and IF one can see the AFM on a gauge in their car to monitor this situation......why CAN'T the AFM data be used to modify the cars AFM in realtime...thereby eliminating the problem??

It seems to me, the data is there to do such a thing, it's just not being used.

Am I am idiot :) ?
 

·
Registered
Joined
·
907 Posts
The Lotus ECU i believe does not allow you to do so, It will always go back to stock tune, to overcome this you would need to upgrade to a ECU that will allow a manual tune whereby eliminating the lean out.

I believe there is a tread here about a lotus owner that did nothing but change the ECU and just by re-tuning got 30hp and 32ft lbs of torque. His stock elise was generating more hp than a SC model.
 

·
Registered
Joined
·
10,000 Posts
Because the car does not monitor AFR, it monitors too rich and too lean and just right, however the pulley size causes more boost which in turn increases fuel pressure, fuel pressure isn't monitored so it can't adjust it accordingly, thats about it.

the math uses the fuel pressure sent as a constant, if you modify it then the math is off.
 

·
Registered
Joined
·
826 Posts
Discussion Starter #4
Because the car does not monitor AFR, it monitors too rich and too lean and just right, however the pulley size causes more boost which in turn increases fuel pressure, fuel pressure isn't monitored so it can't adjust it accordingly, thats about it.

the math uses the fuel pressure sent as a constant, if you modify it then the math is off.
BAM....the answer I was looking for. Is this because the software is...I duno...8 bit? hahah..or something. Why would they not want to monitor anything and everything...even if they didn't want to put that data to use? Also, according to the ECU then...the fuel pressure is always a number...not just X...the number is set at the factory?
 

·
Registered
Joined
·
907 Posts
Because the car does not monitor AFR, it monitors too rich and too lean and just right, however the pulley size causes more boost which in turn increases fuel pressure, fuel pressure isn't monitored so it can't adjust it accordingly, thats about it.

the math uses the fuel pressure sent as a constant, if you modify it then the math is off.
Thanks Charlie for the technical breakdown
 

·
Registered
Joined
·
10,000 Posts
Because the OEM and the EPA doesn't want you screwing with the pulley, which is one of the reasons the newer cars have them jammed on.

Some cars come with wideband sensors which allow them to get better data.

Narrow bands are extremely good at detecting 14.6 (for gas cars) but they get less accurate as they get further away, widebands are better at decting a wider range, the EPA wants you at 14.6.
 

·
Banned
Joined
·
874 Posts
MANNNNNNNNNN I thot i would be reading something interesting about some idiot messing up. Thanks for crushing my hopes:)
 

·
Registered
Joined
·
826 Posts
Discussion Starter #8
Because the OEM and the EPA doesn't want you screwing with the pulley, which is one of the reasons the newer cars have them jammed on.

Some cars come with wideband sensors which allow them to get better data.

Narrow bands are extremely good at detecting 14.6 (for gas cars) but they get less accurate as they get further away, widebands are better at decting a wider range, the EPA wants you at 14.6.
Ahhh yeah that makes sense in regards to the OEM, I really appreciate your responses to my questions.

What do you mean by wide/narrow band sensors? And what does 14.6 represent.

Feel free to stop answering my questions at any point, like I said, I'm just a nerd in need of nerdy info.
 
1 - 8 of 8 Posts
Top