Dynamic MAP Enhancer Project

[Painless]

First off, I'd like to say that MAP enhancers scare me and that fact is the main drive for this project.

Why do they scare me?

MAP enhancers come mainly in two flavours, single pot and dual city/highway pot. They are usually made from standard potentiometers with nice, easy to use, turn knobs and, from what I've seen so far, people without enough knowledge like to fiddle with them as if there is a label on them saying "Turn me this way for more MPG". Without an EGT gauge, this is a dangerous activity (as is any A/F ratio adjustment). I particularly remember a video higherpoweredh2o posted mentioning a customer who damaged their engine *TWICE* by over zealous cranking of their MAP enhancer.

The problem, as I see it, is that MAP enhancement needs to be proportional to engine load. Higher engine load, such as acceleration from standstill, should use minimal enhancement in order to prevent hesitation or, even worse, pre-detonation. Higher enhancements at average to low load are possible (with an eye on the EGT gauge).

A dual city / highway MAP enhancer goes some way to addressing the above, but still requires driver intervention to flick the SPDT switch over and those two nice big shiny "MPG" knobs are still there to tempt you.

The circuit I'm working on (at the breadboard testing stage at the moment) is designed to work with the more common 5v MAP sensor and has three screwdriver operated "set them right then forget them" multi-turn potentiometers:

1) High Load Enhancement
2) Low Load Enhancement
3) Load Threshold

The circuit compares the incoming MAP sensor signal to determine if the engine load is above the set threshold or below it. If the load is above, the 'high load' enhancement is used. If the load is below, the 'low load' enhancement is used. In addition, if your EGT gauge supports a separate warning light alarm, there is provision to wire this signal to the circuit and cut out all enhancement in the case of a high EGT warning.

As I mentioned, I'm still testing this circuit on breadboard at the moment, but would welcome any input (positive or negative) anyone may have. If the project is successful, this circuit will be released as open source.

Russ.

[velorossa22]

Are you using scangauge to tell you EGT? Does your car automatically monitor EGT or are you using an aftermarket gauge? I've seen them on ebay and they have a probe with them. Where do you install the probe?
I really support a revamp of the MAP sensor enhancer. Seems like there is room for improvement and I like how your addressing it.

[Painless]

I use an aftermarket EGT gauge from gloshift, the probe is mounted in the exhaust manifold just after where the cylinders join into one pipe.

[velorossa22]

Did you have to drill and tap the exhaust manifold?

[Painless]

Did you have to drill and tap the exhaust manifold?

Yep, but it's not as hard as it sounds.

[velorossa22]

So I have a dual Map enhancer on my sooby. But what I don't understand is the dual part of it. With the potentiometer on the right side switched the ohms vary and with the left side switched the ohms vary the same. So it's like either way the both vary the same for the same circuit. So what I don't understand is why have 2 when they mirror each other and only one works at a time?
Something that I thought that might be nice for modification would be a digital volt meter dash mount style. I've seen them on Ebay for $10 including shipping. That way you could compare original voltage to modified voltage very easily. It says it consumes no voltage so you wouldn't have to worry about it modifying the circuit.
What size drill and tap do you use for the EGT? Does your EGT support warning lights?
How do you know that your map enhancer is actually working? Mines varies voltage from 1.5v ( normal idle) to 0v. But I can't feel any difference in the idle or driving and the car won't die even at 0v. Granted I only did that once since I don't want to be buying a new motor yet.

[Painless]

Your MAP sounds a little strange, usually a MAP signal is from 0 to 5v. Are you sure you've tapped into the right wire?

The point of the dual pots is that one is for city and one is for highway. You can, generally, use more enhancement on the highway and less in the city (due to the stop/start higher load requirements). You set each one appropriately and flick the switch depending on the type of driving you're doing.

My gauge does support a warning light. I can't remember the tap size I used, but if you go to gloshiftdirect you can download the installation PDF. I got the correct tap from NAPA.

Russ.

[velorossa22]

The input voltage to the map is 4.5v and coming out at idle is 1.5v. The way I hooked it up is the output of the map to the input of the enhancer then the output of the enhancer connects to the output of the map going to the ecu. I didn't touch the input of the MAP ( the 4.5v one). Is that correct installation?
So if the highway allows for more adjustment then the highway knob should have different resistance at the same setting than the city one right? Otherwise you have 2 of the same thing ( mine has a switch that shifts from one to the other). Unless you are saying that they are supposed run in series?...
Thanks for you help Russ I appreciate it.

[Painless]

Both pots provide the same resistance at the same amount of turn.

The point is that the switch toggles which pot is active, one setting for city and another for highway driving.

[velorossa22]

Wow I'm an idiot. I totally get it now. You're NOT supposed to be always adjusting it you just have to set and what ever you want and you switch between them once you have it dialed in as to what resistance you want for each one.
Okay thanks for helping me get me head screwed on straight!