Chip ?
02-23-2005, 10:59 AM
#61
Three Wheelin'
Join Date: Jun 2001
Location: Winterville, NC
Posts: 1,688
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by jimbo1111
Lets look at a stock 944t for example witch has a afm. My only mod would be to drop in a set of 55 lb injectors. I just increased the effective range of my afm. You ask how. Because the limit of the afm signal never has to reach 5 volts because I am getting the same fueling 37% earlier. So I just increased the effective range with no other mod.
Changing injectors changes fuel delivery...not air volume injested by the engine at a given RPM and load...thats what the VAF...MAF...or MAP sensor does.
Dude...read a few books on engine management
02-23-2005, 11:15 AM
#64
Addict
Rennlist Member
Rennlist
Site Sponsor
Rennlist Member
Rennlist
Site Sponsor
Jimbo, best of luck in your project. I think AWilson gave a very solid advice!
I will no longer respond to this thread, I no longer see it as productive...
I will no longer respond to this thread, I no longer see it as productive...
02-23-2005, 11:17 AM
#65
Racer
Join Date: Jun 2001
Location: Huntingtown, MD
Posts: 363
Likes: 0
Received 0 Likes
on
0 Posts
You mentioned in a earlier post that a afm signal could never grow but I will show you how it can.
Again I will reiterate: You can put larger injectors in and effectively scale back the afm input, but you SHOULD remap the 3D fuel/ignition maps in the chip. The other approach is to reprogram the chip to calculate the correct air flow and required fuel for the specific afm and injectors. EACH approach can work, both require a reprogrammed chip. As to which I prefer, since the DME load value (which is derived from air flow and rpm) is spread out and used in so many places in the code and maps, it is easier to just change the air flow calculation than hunt down and change all the affected load values. Good luck finding someone to do that for you.
02-23-2005, 11:33 AM
#66
Addict
Rennlist Member
Rennlist Member
Join Date: Oct 2003
Location: Indy
Posts: 1,750
Likes: 0
Received 0 Likes
on
0 Posts
Everyone answered that your original question contains an incorrect assumption therefore they can't answer the question.
They are basically telling you that scaling is how you adjust the DME when moving to larger injectors. This is assuming two things. First, your chips are currently adequate for your setup. Secondly, the injectors are the only change.
If you are changing the injectors AND using a larger turbo, you will need remapped chips. These chips will have a map that can be scaled to multiple injector sizes.
At some point, the AFM (or MAF that is calibrated to emulate the AFM) will not be able to measure the load present. Basically, it has an upper limit on its ability to measure CFM of air.
So I guess we should go back and see what you are trying to achieve in whole. Are you just swapping injectors into a setup that shouldn't flow any more CFM? OR are you trying to accomodate a setup that will require more fuel for a given load?
They are basically telling you that scaling is how you adjust the DME when moving to larger injectors. This is assuming two things. First, your chips are currently adequate for your setup. Secondly, the injectors are the only change.
If you are changing the injectors AND using a larger turbo, you will need remapped chips. These chips will have a map that can be scaled to multiple injector sizes.
At some point, the AFM (or MAF that is calibrated to emulate the AFM) will not be able to measure the load present. Basically, it has an upper limit on its ability to measure CFM of air.
So I guess we should go back and see what you are trying to achieve in whole. Are you just swapping injectors into a setup that shouldn't flow any more CFM? OR are you trying to accomodate a setup that will require more fuel for a given load?
Originally Posted by jimbo1111
Many venders now sell chips that allow you to run with different injectors using the fqs. The way I understand it is that when you scale back the fuel with the fqs your scaling back the whole fuel curve. Wouldn't that just make the 55 lb injector look like a stock 36 lb injector or not? I can see how this would help with part throttle but when wot you wouldn't have the fuel you need. I have run 55lb injectors with afm chips and have seen the 02 sensor compensate for part throttle on it's own. Can someone shed some light. Thanks
02-23-2005, 11:39 AM
#67
Banned
Thread Starter
I'm glad you agree with me TT. Your correct that I will be hard press to find someone to program a chip for me in this manner except for you or danno maybe. I guess I just will have to bail his *** out of jail. You sound like a stand up guy thats not one sided. On a side note. We all know how critical timing is on a 8 valve head right.
02-23-2005, 11:46 AM
#68
Rennlist Member
Join Date: Feb 2003
Location: Chicago
Posts: 3,526
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by jimbo1111
I'm glad you agree with me TT. You sound like a stand up guy thats not one sided. On a side note. We all know how critical timing is on a 8 valve head right.
02-23-2005, 04:44 PM
#69
Banned
Thread Starter
Now that some of you agree with me lets address timing. In theory I could scale back timing with the fqs. All I have to do is scale it back 37% and both fuel and timing maps will meet at the correct spot. What do you think about that TT? Pretty clever.
Last edited by jimbo1111; 02-23-2005 at 05:35 PM.
02-23-2005, 06:19 PM
#70
Racer
Join Date: Jun 2001
Location: Huntingtown, MD
Posts: 363
Likes: 0
Received 0 Likes
on
0 Posts
In theory all things are possible.
Now to get you from point A to point B.
This should get your car working with the 55lb injectors and MAF.
Now to get you from point A to point B.
- Go buy and install a DTA, SDS, TEC II/III, or Link, etc. aftermarket engine management system, take your pick.
- Learn everything about the system you selected and how it will work in your car.
- Bug the sh$t out of the manufacturer to help you with any problem areas (you paid for it).
- Go to a dyno and spend the day/week/month/year tuning the fuel and ignition maps, some people here will share their maps with you to get you started.
- Keep a detailed log of everything you do during this project (good and bad) and post it back here to help those who might want to follow your lead.
- Go enjoy the car.
This should get your car working with the 55lb injectors and MAF.
02-23-2005, 06:24 PM
#71
Rennlist Member
Join Date: Feb 2003
Location: Chicago
Posts: 3,526
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by TT
In theory all things are possible.
Now to get you from point A to point B.
This should get your car working with the 55lb injectors and MAF.
Now to get you from point A to point B.
- Go buy and install a DTA, SDS, TEC II/III, or Link, etc. aftermarket engine management system, take your pick.
- Learn everything about the system you selected and how it will work in your car.
- Bug the sh$t out of the manufacturer to help you with any problem areas (you paid for it).
- Go to a dyno and spend the day/week/month/year tuning the fuel and ignition maps, some people here will share their maps with you to get you started.
- Keep a detailed log of everything you do during this project (good and bad) and post it back here to help those who might want to follow your lead.
- Go enjoy the car.
This should get your car working with the 55lb injectors and MAF.
nice! hee hee
02-23-2005, 06:45 PM
#72
Banned
Thread Starter
Danno if your out there and think that my idea would work please pm me. If you could give me a chip that will work as I discribed. Send me a mock up. I have a very close friend that happens to own the largest elevator manufacturing plant in the u.s.a. I could burn you an infinate number of chip in a clean room enviroment. Your chip will never again be faulty. And will be maf spicific.
02-24-2005, 10:28 PM
#74
Banned
Thread Starter
John and tt. It just came to me how your maf works. I will not post it here because I really don't what to hurt anybody's business by doing so. It's so simple it's not funny. But dam does it work.
