IAC or no IAC? MAF or no MAF?
Moderators: jsmcortina, muythaibxr
IAC or no IAC? MAF or no MAF?
Hey all, I'm still working on rewiring my MS2 to fit my setup/combo. MS2 was installed by the previous owner and I believe he wasn't using an IAC valve. I'm running a 306 with Cobra intake. Should I use an IAC valve or just adjust it with the idle screw?
Also, should I run a MAF or leave it setup as speed density?
This is a street strip car and won't be daily driven. I'd just like to know what would be best. Thanks in advance!
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Also, should I run a MAF or leave it setup as speed density?
This is a street strip car and won't be daily driven. I'd just like to know what would be best. Thanks in advance!
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Jeremy
Re: IAC or no IAC? MAF or no MAF?
You'll never get it to idle under all conditions without the IAC. Idle stop screw is only the base setting. It's like saying: "Can I run the same base timing all the time or the same AFR all the time?"
MAF or SD, or both? I use both, MAF for fuel, MAP for spark.
MAF or SD, or both? I use both, MAF for fuel, MAP for spark.
1988 Mustang GT, 59k miles, Orig Owner
ProCharger 600B I/C, 12psi, FRP Hdrs, Flwmstr F2, 3G Alt, Contour Fan & DCC, 3.55's, Prog Sprg, Subfms, UCA, LCA, FCA, Tokico 5's, Bridgestone RE-71R 245/40R17, Crane HI-6, Kirban FPR, MS2, DIYPNPF60, Spartan 2, C&L76mm blo-thru MAF, 47lb FRP-LU47
ProCharger 600B I/C, 12psi, FRP Hdrs, Flwmstr F2, 3G Alt, Contour Fan & DCC, 3.55's, Prog Sprg, Subfms, UCA, LCA, FCA, Tokico 5's, Bridgestone RE-71R 245/40R17, Crane HI-6, Kirban FPR, MS2, DIYPNPF60, Spartan 2, C&L76mm blo-thru MAF, 47lb FRP-LU47
Re: IAC or no IAC? MAF or no MAF?
This is how he explained it to me a little earlier:
"Say idle 800rpm. Set idle screw. Set timing at like 10-20*, see where you get highest vacuum. Then, in the timing table, put a block at 600rpm, and go up 2* timing. That way if idle ever falls, the bump in timing brings it right back up"
I don't quite follow what he's saying, but I'm unfamiliar with this system to begin with. I wanna do what's best. I have an IAC valve and a MAF calibrated to the injector size I'll be running.
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"Say idle 800rpm. Set idle screw. Set timing at like 10-20*, see where you get highest vacuum. Then, in the timing table, put a block at 600rpm, and go up 2* timing. That way if idle ever falls, the bump in timing brings it right back up"
I don't quite follow what he's saying, but I'm unfamiliar with this system to begin with. I wanna do what's best. I have an IAC valve and a MAF calibrated to the injector size I'll be running.
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Jeremy
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- Master MS/Extra'er
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Re: IAC or no IAC? MAF or no MAF?
What he's saying about the idle tuning isn't exactly wrong. The idea is that if RPMs drop, the extra timing commanded in the 600 row should help the engine speed recover back up to the 800 range. However, cold starts become much easier with an IAC. I ran without one for a few years, and while it worked, it was less than ideal. Speaking from experience, IAC = much better. Don't Fords use a PWM controlled IAC? Super simple to wire. Spend the extra few minutes to wire & install it. You won't regret it.
-Dave
-Dave
'70 Chevelle ZZ383/700r4/3.73 MS3X, 36-1, LS Coils, Holley Stealthram -- success story
'92 Saturn 1.9 DOHC/5sp, MS3, Champcar racer success story
'79 Malibu DartSHP400/80mm/PG/3.55, MS3X/36-1/LS Coils -- success story
Porsche 944 S2 3.0 -- MS3X/36-1/LS Coils, 1:44s Mid-Ohio, Pro Course
'92 Saturn 1.9 DOHC/5sp, MS3, Champcar racer success story
'79 Malibu DartSHP400/80mm/PG/3.55, MS3X/36-1/LS Coils -- success story
Porsche 944 S2 3.0 -- MS3X/36-1/LS Coils, 1:44s Mid-Ohio, Pro Course
Re: IAC or no IAC? MAF or no MAF?
I'm not sure how factory Ford IACs are controlled. I wanna do what will give me the best results. Wiring up the IAC doesn't seem like a big deal, so if it will be best then that's what I'll do. Same goes for the MAF. I don't mind a little extra work now for better results when the car is running.ChevelleFan wrote:What he's saying about the idle tuning isn't exactly wrong. The idea is that if RPMs drop, the extra timing commanded in the 600 row should help the engine speed recover back up to the 800 range. However, cold starts become much easier with an IAC. I ran without one for a few years, and while it worked, it was less than ideal. Speaking from experience, IAC = much better. Don't Fords use a PWM controlled IAC? Super simple to wire. Spend the extra few minutes to wire & install it. You won't regret it.
-Dave
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Jeremy
Re: IAC or no IAC? MAF or no MAF?
Do you want a IAC or not?
You can setup MS not to have idle control at all, but if you have a/c, want idle RPM at all time, etc, you want an IAC
You can setup MS not to have idle control at all, but if you have a/c, want idle RPM at all time, etc, you want an IAC
Start here. Find out how the factory FORD IAC is controlled, then wire it up accordingly.ponie1992 wrote:I'm not sure how factory Ford IACs are controlled. I
1985 Dodge Omni GLH Turbo MicroSquirted 367whp http://www.msextra.com/forums/viewtopic ... 04&t=67324
Re: IAC or no IAC? MAF or no MAF?
MAF won't work unless you have the calibrations curves & enter them into Tuner Studio. Calibrating to you injectors was an EEC-IV work around. Does not apply to Megasquirt.ponie1992 wrote:I'm not sure how factory Ford IACs are controlled. I wanna do what will give me the best results. Wiring up the IAC doesn't seem like a big deal, so if it will be best then that's what I'll do. Same goes for the MAF. I don't mind a little extra work now for better results when the car is running.
1988 Mustang GT, 59k miles, Orig Owner
ProCharger 600B I/C, 12psi, FRP Hdrs, Flwmstr F2, 3G Alt, Contour Fan & DCC, 3.55's, Prog Sprg, Subfms, UCA, LCA, FCA, Tokico 5's, Bridgestone RE-71R 245/40R17, Crane HI-6, Kirban FPR, MS2, DIYPNPF60, Spartan 2, C&L76mm blo-thru MAF, 47lb FRP-LU47
ProCharger 600B I/C, 12psi, FRP Hdrs, Flwmstr F2, 3G Alt, Contour Fan & DCC, 3.55's, Prog Sprg, Subfms, UCA, LCA, FCA, Tokico 5's, Bridgestone RE-71R 245/40R17, Crane HI-6, Kirban FPR, MS2, DIYPNPF60, Spartan 2, C&L76mm blo-thru MAF, 47lb FRP-LU47
Re: IAC or no IAC? MAF or no MAF?
I'd like to know what would be best. The car is a street strip Mustang. No AC.tryingbe wrote:Do you want a IAC or not?
You can setup MS not to have idle control at all, but if you have a/c, want idle RPM at all time, etc, you want an IAC
Start here. Find out how the factory FORD IAC is controlled, then wire it up accordingly.ponie1992 wrote:I'm not sure how factory Ford IACs are controlled. I
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Jeremy
Re: IAC or no IAC? MAF or no MAF?
Cool, that answers that question. Thanks!Blown88GT wrote:MAF won't work unless you have the calibrations curves & enter them into Tuner Studio. Calibrating to you injectors was an EEC-IV work around. Does not apply to Megasquirt.ponie1992 wrote:I'm not sure how factory Ford IACs are controlled. I wanna do what will give me the best results. Wiring up the IAC doesn't seem like a big deal, so if it will be best then that's what I'll do. Same goes for the MAF. I don't mind a little extra work now for better results when the car is running.
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Jeremy
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- Master MS/Extra'er
- Posts: 789
- Joined: Sun May 02, 2004 5:55 pm
- Location: Cleveland, Ohio
- Contact:
Re: IAC or no IAC? MAF or no MAF?
My Chevelle is street/strip too. Do the IAC. Seriously.ponie1992 wrote:I'd like to know what would be best. The car is a street strip Mustang. No AC.tryingbe wrote:Do you want a IAC or not?
You can setup MS not to have idle control at all, but if you have a/c, want idle RPM at all time, etc, you want an IAC
Start here. Find out how the factory FORD IAC is controlled, then wire it up accordingly.ponie1992 wrote:I'm not sure how factory Ford IACs are controlled. I
Sent from my SM-N950U using Tapatalk
-Dave
'70 Chevelle ZZ383/700r4/3.73 MS3X, 36-1, LS Coils, Holley Stealthram -- success story
'92 Saturn 1.9 DOHC/5sp, MS3, Champcar racer success story
'79 Malibu DartSHP400/80mm/PG/3.55, MS3X/36-1/LS Coils -- success story
Porsche 944 S2 3.0 -- MS3X/36-1/LS Coils, 1:44s Mid-Ohio, Pro Course
'92 Saturn 1.9 DOHC/5sp, MS3, Champcar racer success story
'79 Malibu DartSHP400/80mm/PG/3.55, MS3X/36-1/LS Coils -- success story
Porsche 944 S2 3.0 -- MS3X/36-1/LS Coils, 1:44s Mid-Ohio, Pro Course
Re: IAC or no IAC? MAF or no MAF?
Gotcha. Looks like I'll be using the IAC. Thanks!ChevelleFan wrote:My Chevelle is street/strip too. Do the IAC. Seriously.ponie1992 wrote:I'd like to know what would be best. The car is a street strip Mustang. No AC.tryingbe wrote:Do you want a IAC or not?
You can setup MS not to have idle control at all, but if you have a/c, want idle RPM at all time, etc, you want an IAC
Start here. Find out how the factory FORD IAC is controlled, then wire it up accordingly.
Sent from my SM-N950U using Tapatalk
-Dave
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Jeremy
Re: IAC or no IAC? MAF or no MAF?
One comment. Don't get bogged down trying to incorporate everything right away. I plan to add IAC eventually, but you certainly don't have to have it to get your project on the road. Not having to sort out the idle valve issues with early stages of tuning is a benefit. You can certainly do all the things together, but tuning all things at the beginning can be overwhelming. As you learn, you find things you may want to do differently, so it can be hard to do it perfectly the first time and regret tearing up the wiring you "thought" you would never need to change.
Re: IAC or no IAC? MAF or no MAF?
I was thinking along these lines lately. Just get her running for now and then add things in if necessary.cactus wrote:One comment. Don't get bogged down trying to incorporate everything right away. I plan to add IAC eventually, but you certainly don't have to have it to get your project on the road. Not having to sort out the idle valve issues with early stages of tuning is a benefit. You can certainly do all the things together, but tuning all things at the beginning can be overwhelming. As you learn, you find things you may want to do differently, so it can be hard to do it perfectly the first time and regret tearing up the wiring you "thought" you would never need to change.
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Jeremy