Part throttle boost and AFR?

[Speedy1234]

I've got a 2009 Challenger with the 5.7 Hemi in it. I had originally intended to put a supercharger on this car, but it seems tuning part throttle boost can be a problem.

There are a couple of solutions, one of which being having the bypass set such that boost is avoided at part throttle. This seems to defeat the purpose of a blower to me. If I can't have boost when I want it, what's the point.

So my question is to you Camaro or Mustang guys with FI. How do your cars handle part throttle boost? Is it able to be tuned in or are you running some piggy back or other module that allows for closed loop fuel enrichment?

I guess I'm wondering if this is a problem inherent to the Hemi, or if this is a common cross platform issue.

[slow00gt]

I had adaptive learning off and this made my car stay in open loop at all times. Just have to take time to get your afr right across the rpms at part throttle. Dunno if dodges will have this in tuning or not but a ford does. Only way I have figured out how to control my afr at part throttle. Its a a seperate table from my wot tables

[Speedy1234]

I had adaptive learning off and this made my car stay in closed loop at all times. Just have to take time to get your afr right across the rpms at part throttle. Dunno if dodges will have this in tuning or not but a ford does. Only way I have figured out how to control my afr at part throttle. Its a a seperate table from my wot tables

Ok, that is another solution I've read about...keeping the car in open loop all the time. However that makes gas mileage terrible from what I've heard.

How do the Ford power up options handle this? Ford offers several supercharger packages from the dealer. Do you know how those packages handle part throttle boost?

Here's an example:

Ford Racing Performance Parts - [Part Details]

Here's a link to their "ProCal Tool":

http://www.fordracingparts.com/downl...09_Article.pdf

[Bob-E]

It just needs to be tuned. No different than a factory supercharged car. Take it to a shop instead of listening to internet noobs playing with their tunning gadgets.

If you don't have a way to tune the ecu, then that's another story, but I'm pretty sure it can be done no problem.

[slow00gt]

I never used any of those for tuning. I have the moates Quaterhorse and love it. The ability to tune with this on the fly without shutting the car off is what sold me and for 249.99 its a good price. Also has live datalogging You have to get software to run this. I use Binary editor which was 80$ and its a very nice program. I lost a little bit on mpg but as long as I kept it out of boost it was fine. But I am running a turbo so a lil easier to stay out of boost. Tuning with adaptive learning off just takes a lot of time to get perfect.

[Speedy1234]

It just needs to be tuned. No different than a factory supercharged car. Take it to a shop instead of listening to internet noobs playing with their tunning gadgets.

If you don't have a way to tune the ecu, then that's another story, but I'm pretty sure it can be done no problem.

It's A LOT different than a factory supercharged car.

From the factory I'm pretty confident the ECM knows what boost is. Then has a fuel map for boost.

NA cars don't have that, so it's all tricks and gimmicks to fool the computer.

I'm just wondering if that's the case for all brands, for just the Hemi in particular.

Bottom line you don't want to be driving around at 14.7:1 AFR and boost. I've asked a lot of people and most don't even have AFR gauges in their supercharged or turbo cars so they're clueless.

WOT (open loop) can be tuned on the Hemi....it's the part throttle areas I'm concerned with. How often am I gonna be driving around at WOT in a 500RWHP car vs. part throttle....

[ZTwentyAteU]

It's A LOT different than a factory supercharged car.

From the factory I'm pretty confident the ECM knows what boost is. Then has a fuel map for boost.

NA cars don't have that, so it's all tricks and gimmicks to fool the computer.

I'm just wondering if that's the case for all brands, for just the Hemi in particular.

Bottom line you don't want to be driving around at 14.7:1 AFR and boost. I've asked a lot of people and most don't even have AFR gauges in their supercharged or turbo cars so they're clueless.

WOT (open loop) can be tuned on the Hemi....it's the part throttle areas I'm concerned with. How often am I gonna be driving around at WOT in a 500RWHP car vs. part throttle....

Unless the dodge PCM is completely retarded, I don't see why its going to be a problem. Looks to me like every tom dick and harry shop has a blower stuck on a mustang, camaro, or challenger. Seems to me like you are doing way too much reading up on the interwebz. There usually is no "special tables," almost every late model PCM has a wide enough range of fueling and air tables to do whatever you want to do, all you need to do is spend a little time hitting all the cells and retuning them. Part throttle tuning just takes time, its no where near impossible.

[2burnouts]

give speedys in owensboro a call.

[tooslow]

It's A LOT different than a factory supercharged car.

From the factory I'm pretty confident the ECM knows what boost is. Then has a fuel map for boost.

NA cars don't have that, so it's all tricks and gimmicks to fool the computer.

I'm just wondering if that's the case for all brands, for just the Hemi in particular.

Bottom line you don't want to be driving around at 14.7:1 AFR and boost. I've asked a lot of people and most don't even have AFR gauges in their supercharged or turbo cars so they're clueless.

WOT (open loop) can be tuned on the Hemi....it's the part throttle areas I'm concerned with. How often am I gonna be driving around at WOT in a 500RWHP car vs. part throttle....

He meant it's no different than a supercharged vehicle from the factory, meaning the pcm was tuned for the supercharger. Tuning your particular car for boost should be no problem with the right software and tuner.

[Speedy1234]

Maybe I'm not asking the question in a clear way.

Can anyone tell me specifically how the closed loop air fuel ratio is changed on a supercharged Mustang?

Does it drop in to open loop early based on TPS volts or ?

Note, the key word here being "closed loop". I'm trying to understand the differences between the Hemi and other cars. The Hemi is MAP based, and I believe the Mustang and Camaro are MAF.

I can tell you on the Challenger it's a big problem. I'm no noobie even though my post count here is quite low.

I have a supercharged 4Runner that I tuned myself, but I had to use a piggy back with a special add-on that allows close loop fuel enrichment.

I really don't want to have to fool with piggybacks again.

[Bob-E]

02 sensor and fuel trim. I think you are confused on open and closed loop. Open loop is hardly limited to WOT. There is usually a crossover point set by things like load, tps, rpm, etc.

[Speedy1234]

02 sensor and fuel trim. I think you are confused on open and closed loop. Open loop is hardly limited to WOT. There is usually a crossover point set by things like load, tps, rpm, etc.

Yep, I got all that. I'm pretty well versed in the workings of open/closed loop.

So on Mustangs you're saying they lower the point where Open Loop occurs throttle wise?

2011 Mustangs may really be the tuner cars. They're rumored to have full Wide Band sensors in the exhaust from the factory. Should make tuning very easy.

[QuickSilverZ]

On the Vettes & Camaros, with a little tweaking the PCM can handle the part throttle with no problem. My car runs near 14.7 at part throttle under boost. Not a big deal. If the Hemi is MAP based then it is like a speed density tune, which is even better. That way the PCM will compensate for different boost levels based on the MAP reading. You might have to change to a 2 bar MAP, depending what the factory on is.

Just be sure to get WOT right using a AFR gauge and adjust part throttle primarily for driveability.

Tuning is not for the faint of heart and you can really mess things up quickly. Do your homework, before you start.

[Bob-E]

Yep, I got all that. I'm pretty well versed in the workings of open/closed loop.

So what's the problem then

1st I would find out what engine management is available for your car. ECU hack? SCT? Mopar chip? FAST standalone? Do you want to make your own? Then I would ask them how they adjust fueling. Is the car map or maf based?

[Disney Lincoln]

It's all in the load. If the ECU sees X amount of throttle angle (TPS voltage) and it's moving Y amount of Airflow through the MAF, then it gives it Z amount of fuel. Very easy to understand, but as easy to tune.