HOME FORUM RULES CONTACT
     
   
   

Go Back   CLASS RACER FORUM > Class Racer Forums > Stock and Super Stock Tech


Reply
 
Thread Tools Display Modes
Old 02-26-2021, 06:56 PM   #1
HawkBrosMav
Member
 
Join Date: Apr 2009
Posts: 356
Likes: 6
Liked 276 Times in 68 Posts
Default Holly HP EFI-- Idle & IAC Tuning

Anyone have some decent pointers and/or starting points on how to improve start up and idle on a Holley HP system on a 88 Ford 302 using the stock Ford IAC? We've had this deal on the car a couple years now and the drivability down the track has been great.. starting it to get there and sometimes stalling it up smoothly has been inconsistent to terrible to say the least. I've done some research but I just don't know enough to put it all together and make the car happy.

Any help or pointers would be great.

Thanks
Brad
HawkBrosMav is offline   Reply With Quote
Old 02-28-2021, 11:22 AM   #2
Jeff Niceswanger
Senior Member
 
Join Date: Jul 2003
Posts: 764
Likes: 580
Liked 833 Times in 290 Posts
Default Re: Holly HP EFI-- Idle & IAC Tuning

Quote:
Originally Posted by HawkBrosMav View Post
Anyone have some decent pointers and/or starting points on how to improve start up and idle on a Holley HP system on a 88 Ford 302 using the stock Ford IAC? We've had this deal on the car a couple years now and the drivability down the track has been great.. starting it to get there and sometimes stalling it up smoothly has been inconsistent to terrible to say the least. I've done some research but I just don't know enough to put it all together and make the car happy.

Any help or pointers would be great.

Thanks
Brad
Nobody has spoke up so I'll try to help a little. I have a dozen or so tunes in class cars and have gotten completely away from using the IAC.I tried using mine in my personal car, but it has more disadvantages than advantages. I used a IAC all one summer and I think they are a waste of time. Its hard to keep them from surging around with the camshafts we use. And I don't see why its needed? It's just one other thing to mess with. If using the Holley, "uncheck/disable" the IAC in your settings and work on your idle/off idle areas a little ..
__________________
Jeff Niceswanger 3740 SS
Jeff Niceswanger is offline   Reply With Quote
Old 02-28-2021, 11:32 AM   #3
BRETV
Member
 
Join Date: Oct 2003
Posts: 486
Likes: 2,949
Liked 596 Times in 147 Posts
Default Re: Holly HP EFI-- Idle & IAC Tuning

Just like Jeff said, we completely disabled the IAC and left it unplugged, had the same issue with the same 5.0 stock combo, we were using an Accel DFI system back then, shouldn't matter though, we turned the idle screw up on the throttle body and took care of it, idled a little high but we didn't mind.





Bret Velde
2003 ??/SA
BRETV is offline   Reply With Quote
Liked
Old 02-28-2021, 11:30 PM   #4
Kevin Panzino
Senior Member
 
Kevin Panzino's Avatar
 
Join Date: Oct 2002
Location: Pittsburgh
Posts: 519
Likes: 243
Liked 547 Times in 105 Posts
Default Re: Holly HP EFI-- Idle & IAC Tuning

Yep, Brother Niceswanger is not just another pretty face.
Agree 100% with his comments.
No need for IAC, and in fact nothing but problems with IAC and the cams we run in these class combinations.
Either remove the IAC and block it off, or make sure its in the fully closed position then unplug it and leave it unplugged. Then work the throttle blade stop setscrew like the old days to set the idle RPM, and then tweak the fuel map in that range for a nice clean idle, and crisp off idle smacks.

Easy peazy and no surprises with hunting/surging, overshoot, stalling as you try to make your way to the lanes with an iced-up intake for class when your IAC is going nuts because of that....
Kevin Panzino is offline   Reply With Quote
Liked
Old 03-01-2021, 03:05 PM   #5
Robin Lawrence
Sponsor
 
Join Date: Jan 2002
Location: Galesburg IL.
Posts: 161
Likes: 209
Liked 621 Times in 108 Posts
Default Re: Holly HP EFI-- Idle & IAC Tuning

Just saw this post. Bradenton-SGMP-Bradenton I haven't had a chance to respond. I agree with the suggestions above.

There are many ways to make them happier but they are a little more complicated.

One things is be sure that the injector data is correct. Voltage Offsets if wrong can make the injectors inconsistent in their operation.

Another is to look at your target idle speed. Be sure that the TPS reading returns to 0 or 1 at the idle setting. If using Idlespark it needs to be within 200 RPM of the target to work well.
Idlespark with chase the idle speed with timing up or down 8 degrees.

If it doesn't start well your cranking fuel or timing might need some work. Also after start enrichment for the first 100 seconds or so after startup.

If using the closed loop function on a stocker with no exhaust you need to turn it off util a higher flow through the collector. Anywhere from 4000 to 6000 RPM. Below that you will need to massage the fuel table to make it happy in open loop.

That's a good start of several things to look at.

Robin
__________________
STK 308
SS 3088
Robin Lawrence is offline   Reply With Quote
Liked
Old 03-01-2021, 03:38 PM   #6
Glenn Briglio
VIP Member
 
Glenn Briglio's Avatar
 
Join Date: Nov 2002
Location: Massapequa Park,NY
Posts: 1,205
Likes: 1,719
Liked 819 Times in 263 Posts
Default Re: Holly HP EFI-- Idle & IAC Tuning

Quote:
Originally Posted by Robin Lawrence View Post
Just saw this post. Bradenton-SGMP-Bradenton I haven't had a chance to respond. I agree with the suggestions above.

There are many ways to make them happier but they are a little more complicated.

One things is be sure that the injector data is correct. Voltage Offsets if wrong can make the injectors inconsistent in their operation.

Another is to look at your target idle speed. Be sure that the TPS reading returns to 0 or 1 at the idle setting. If using Idlespark it needs to be within 200 RPM of the target to work well.
Idlespark with chase the idle speed with timing up or down 8 degrees.

If it doesn't start well your cranking fuel or timing might need some work. Also after start enrichment for the first 100 seconds or so after startup.

If using the closed loop function on a stocker with no exhaust you need to turn it off util a higher flow through the collector. Anywhere from 4000 to 6000 RPM. Below that you will need to massage the fuel table to make it happy in open loop.

That's a good start of several things to look at.

Robin
Hey Robin is there any issue with using the primary pipe on header for O2 to ecm tuning during a run?
__________________
1989 Camaro Iroc-Z I/SA B&B Auto Machine Shop.
Glenn Briglio is offline   Reply With Quote
Old 03-01-2021, 05:15 PM   #7
Robin Lawrence
Sponsor
 
Join Date: Jan 2002
Location: Galesburg IL.
Posts: 161
Likes: 209
Liked 621 Times in 108 Posts
Default Re: Holly HP EFI-- Idle & IAC Tuning

Quote:
Originally Posted by Glenn Briglio View Post
Hey Robin is there any issue with using the primary pipe on header for O2 to ecm tuning during a run?
Not really any issue. Chevrolet Performance did just that during testing on the COPO's in 2013 and 2014. I believe they had worked on the cylinder to cylinder on the dyno so it was fairly well matched.

Using the Holley to perform closed loop in the primary allows you to enable closed loop at a lower RPM. The optimum A/F ratio will probably be slightly richer than in the collector. Optimum A/F is relative so it will need to be tested to determine the best for a particular combination.

Robin
__________________
STK 308
SS 3088
Robin Lawrence is offline   Reply With Quote
Old 03-02-2021, 10:45 AM   #8
Signman
Member
 
Join Date: Oct 2003
Location: Lower Slower Delaware
Posts: 492
Likes: 14
Liked 198 Times in 73 Posts
Default Re: Holly HP EFI-- Idle & IAC Tuning

Quote:
Originally Posted by Robin Lawrence View Post
Not really any issue. Chevrolet Performance did just that during testing on the COPO's in 2013 and 2014. I believe they had worked on the cylinder to cylinder on the dyno so it was fairly well matched.

Using the Holley to perform closed loop in the primary allows you to enable closed loop at a lower RPM. The optimum A/F ratio will probably be slightly richer than in the collector. Optimum A/F is relative so it will need to be tested to determine the best for a particular combination.

Robin

Thank You for that Robin.
Been saying the same years.
People have asked me what AFR I run. Usually turn the conversation to asking where their O2 sensor is located and why optimum AFR may be different due to location if simultaneously recorded. Then go on to explain how fresh air is sucked into the collector. At low RPM fresh air influences the sensor even when located in the primary tube.
Not always easy to wrap your head around this stuff but once understood opens a lot of doors of understanding.
__________________
Frank Ferrucci ?/SA 1271
Signman is offline   Reply With Quote
Old 03-02-2021, 01:23 PM   #9
Glenn Briglio
VIP Member
 
Glenn Briglio's Avatar
 
Join Date: Nov 2002
Location: Massapequa Park,NY
Posts: 1,205
Likes: 1,719
Liked 819 Times in 263 Posts
Default Re: Holly HP EFI-- Idle & IAC Tuning

Quote:
Originally Posted by Signman View Post
Thank You for that Robin.
Been saying the same years.
People have asked me what AFR I run. Usually turn the conversation to asking where their O2 sensor is located and why optimum AFR may be different due to location if simultaneously recorded. Then go on to explain how fresh air is sucked into the collector. At low RPM fresh air influences the sensor even when located in the primary tube.
Not always easy to wrap your head around this stuff but once understood opens a lot of doors of understanding.
Use open loop at idle then go to closed loop after 2000 rpm
__________________
1989 Camaro Iroc-Z I/SA B&B Auto Machine Shop.
Glenn Briglio is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 02:40 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright © Class Racer.com. All Rights Reserved. Designated trademarks and brands are the property of their respective owners.