Fuel and ignition mapping

Belgian1979vette

Belgian1979vette

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Joined
Apr 4, 2008
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Koersel/Belgium
I was looking into a way to get the maps on the EFI system right. Basically you need to load the engine to do so, and since I don't have dyno at my disposal and the guys having one won't let me get near it, I normally would have to do this on the street. Now, this would be a 2 man job, one driving, one doing the programming and not exactly the safest thing, doing full throttle runs.

I have been looking into building my own dyno one way or another, but it's practically impossible to build a load cell of some sort without spending ton's of $.

This weekend I was driving down the road with my regular car and when braking at the same time pressed the gas trying to keep rpm the same. This was kind of like loading the engine until the point where I was no longer able to hold rpm steady while increasing the load (braking).

This got me thinking... since my body is still of the car, would there be some way to load the engine with the brakes of the car. However I would have to make something to be able to create enough brake pressure and keep it at a certain point...it is rather difficult doing this with your foot, since it is practically impossible to increase pressure in small enough increments to get the mapping right.

Does anyone now a solution to this.

I have been looking into the ABS modulators since they work with a brakepump, but the problem is still the same, you need your foot to apply an regulate pressure.
 
What EFI system? Don't they have basic starter maps for an engine combo close to yours?
 
You realize what you are asking is not really a safe enviroment to do this. What system are you using? Is your car an auto or manual trans?
 
Why would it blow. It's basically the same as tuning a carbed engine. Enough parameters/controls to keep it under control and below max rpm. Way safer than doing it on the street imo.
 
If you don't make large changes you are not going to blow anything, everyone thinks that tuning is so difficult. Make small adjustments starting with your VE table and you will be fine. I usually start by removing about 5 degrees of timing and using a WB I dial my VE table in. Once that is done, then you can start with the timing table and making some power.
 
J. Abbott said:
If you don't make large changes you are not going to blow anything, everyone thinks that tuning is so difficult. Make small adjustments starting with your VE table and you will be fine. I usually start by removing about 5 degrees of timing and using a WB I dial my VE table in. Once that is done, then you can start with the timing table and making some power.
Click to expand...

I guess you are right. Still have to learn though. The though side is have a base table that is not to far off. I was thinking of maybe installing a carb first with all sensors attached to see how much is approximatly needed with regards to fuel and ignition, then setting things somewhat smaller and starting from there.

Seems like you've got a lott of experience. What type of system do you use ?
 
J. Abbott said:
If you don't make large changes you are not going to blow anything, everyone thinks that tuning is so difficult. Make small adjustments starting with your VE table and you will be fine. I usually start by removing about 5 degrees of timing and using a WB I dial my VE table in. Once that is done, then you can start with the timing table and making some power.
Click to expand...

I need talk to you....some 5? years ago, I built and installed a DIY-EFI / Bruce Bowling computer on my 355 vette, but due to the then use of the serial D connector, I could never get it to run decently, and all attempts to .commm with the thing failed miserably....so the question is....with a more modern GM computer I understand they are addressable with some software and a more simple interface....trick is, it's all gotta be USB compatible with todays laptops....no more 1/2 assed adaptors and antiquated crapola....

how hard is it to do this these days.??

and how hard is it to address various computers on newer cars....

my old system is a speed density like a '91 F body 1227730 batch fire computer, and wondering if maybe another heated O2 sensor and some finer tuning I could get better operation outta it....

or is it worth my time??

Old ET here, I can solder a wire, so that shit don't scare me...it's the programming that is the mystery meat....

:crap:
 
mrvette said:
J. Abbott said:
If you don't make large changes you are not going to blow anything, everyone thinks that tuning is so difficult. Make small adjustments starting with your VE table and you will be fine. I usually start by removing about 5 degrees of timing and using a WB I dial my VE table in. Once that is done, then you can start with the timing table and making some power.
Click to expand...

I need talk to you....some 5? years ago, I built and installed a DIY-EFI / Bruce Bowling computer on my 355 vette, but due to the then use of the serial D connector, I could never get it to run decently, and all attempts to .commm with the thing failed miserably....so the question is....with a more modern GM computer I understand they are addressable with some software and a more simple interface....trick is, it's all gotta be USB compatible with todays laptops....no more 1/2 assed adaptors and antiquated crapola....

how hard is it to do this these days.??

and how hard is it to address various computers on newer cars....

my old system is a speed density like a '91 F body 1227730 batch fire computer, and wondering if maybe another heated O2 sensor and some finer tuning I could get better operation outta it....

or is it worth my time??

Old ET here, I can solder a wire, so that shit don't scare me...it's the programming that is the mystery meat....

:crap:
Click to expand...
Gene,

The RS232 is indeed a problem on a modern laptop. I found an old one that still had one originally and it worked perfectly and communicated just fine with the MS.
 
Belgian1979vette said:
mrvette said:
J. Abbott said:
If you don't make large changes you are not going to blow anything, everyone thinks that tuning is so difficult. Make small adjustments starting with your VE table and you will be fine. I usually start by removing about 5 degrees of timing and using a WB I dial my VE table in. Once that is done, then you can start with the timing table and making some power.
Click to expand...

I need talk to you....some 5? years ago, I built and installed a DIY-EFI / Bruce Bowling computer on my 355 vette, but due to the then use of the serial D connector, I could never get it to run decently, and all attempts to .commm with the thing failed miserably....so the question is....with a more modern GM computer I understand they are addressable with some software and a more simple interface....trick is, it's all gotta be USB compatible with todays laptops....no more 1/2 assed adaptors and antiquated crapola....

how hard is it to do this these days.??

and how hard is it to address various computers on newer cars....

my old system is a speed density like a '91 F body 1227730 batch fire computer, and wondering if maybe another heated O2 sensor and some finer tuning I could get better operation outta it....

or is it worth my time??

Old ET here, I can solder a wire, so that shit don't scare me...it's the programming that is the mystery meat....

:crap:
Click to expand...
Gene,

The RS232 is indeed a problem on a modern laptop. I found an old one that still had one originally and it worked perfectly and communicated just fine with the MS.
Click to expand...

MY problem was the old lap top a buddy gave me SEEMED to .comm with the Mega Squirt ok, I think....but then there was practically no way to send any results that didn't seem to save well at all, to the dealer in Atlanta? region ...so they could not help....

so I wonder about a more modern setup....maybe next year's project, got enough on the table for now, but looking for a proven direction to go, without a bunch of unknowns it takes Einstein to solve....

:waxer::flash:
 
Belgian1979vette said:
MS and yes they have a basic map, but since I will be running an ITB, i doubt it will be close.
Click to expand...

Are the ITBs connected to each other to produce a vacuum signal for a MAP sensor? If not, you will be tuning with RPM and TPS only, much more difficult.

IMO, set the timing where you actually want it, say 15-18 initial, ramped up to 34 degrees all in by 2800.

For fuel, Idle tuning is easy, set it first. If your injectors are sized properly, you will want 8-10 ms of pulse width at peak power. ITBs move a lot of air quickly, so you will want a sharp ramp up from idle to say 2500-3000 rpm and and a more gradual ramp to peak power.

On the dyno don't go up more than 500 rpm at a time and a wideband O2 is highly recommended.

Good luck,

Rob
 
MrForce said:
Belgian1979vette said:
MS and yes they have a basic map, but since I will be running an ITB, i doubt it will be close.
Click to expand...

Are the ITBs connected to each other to produce a vacuum signal for a MAP sensor? If not, you will be tuning with RPM and TPS only, much more difficult.

IMO, set the timing where you actually want it, say 15-18 initial, ramped up to 34 degrees all in by 2800.

For fuel, Idle tuning is easy, set it first. If your injectors are sized properly, you will want 8-10 ms of pulse width at peak power. ITBs move a lot of air quickly, so you will want a sharp ramp up from idle to say 2500-3000 rpm and and a more gradual ramp to peak power.

On the dyno don't go up more than 500 rpm at a time and a wideband O2 is highly recommended.

Good luck,

Rob
Click to expand...

The ITB's will be connected to a common 'tube' to provide for the vacuum signal. I'm still looking into that however,since the manifold has a chamber underneath the runners that can provide a vacuum signal, but I also need some vacuum to run my brakes etc. So i still have to figure out how to do them all.

Wideband O2 is already bought and meant to be implemented.

Thanks for the suggestions. Lots of knowledgable people here apparently.
 
The ITB's will be connected to a common 'tube' to provide for the vacuum signal. I'm still looking into that however,since the manifold has a chamber underneath the runners that can provide a vacuum signal, but I also need some vacuum to run my brakes etc. So i still have to figure out how to do them all.

Wideband O2 is already bought and meant to be implemented.

Thanks for the suggestions. Lots of knowledgable people here apparently.
Click to expand...

Typically, there is not enough vacuum for power brakes. We use a vacuum pump and reservoir.
 
MrForce said:
The ITB's will be connected to a common 'tube' to provide for the vacuum signal. I'm still looking into that however,since the manifold has a chamber underneath the runners that can provide a vacuum signal, but I also need some vacuum to run my brakes etc. So i still have to figure out how to do them all.

Wideband O2 is already bought and meant to be implemented.

Thanks for the suggestions. Lots of knowledgable people here apparently.
Click to expand...

Typically, there is not enough vacuum for power brakes. We use a vacuum pump and reservoir.
Click to expand...

I remember that vacuum is more a function of the cam duration than anything else, or do you mean that itb's cause a problem with vacuum as well...
 
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