tuning for cylinder head work
03-09-2015, 08:47 PM
#1
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tuning for cylinder head work
Was curious who has tuned for cylinder head work. I had my heads sent out to be CNC'd so they flow better and wasn't sure how lean they would want to run once I get them bolted up. Car is stock except for headers and the head work.
03-12-2015, 12:30 PM
#2
Drifting
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St. Jude Donor '08
Headers and higher flowing heads certainly would be better served with a tune. Unknown, but these two together probably cause a lean condition that under certain conditions the fuel trims cannot correct.
Last edited by jim2092; 03-12-2015 at 12:32 PM.
03-12-2015, 06:57 PM
#3
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Derivable while street tuning would be ok? I figured I'd correct for fuel trims and the VVE map.
03-14-2015, 11:41 AM
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St. Jude Donor '08
Go to the forum for your software; HP Tuner, EFI, etc. You will find plenty of help there. A number of tuning changes can be made for that engine; torque mngt, PE, MAF, etc.
03-14-2015, 08:20 PM
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St. Jude Donor '13-'14-'15
Too many unknowns to say exactly how better flowing heads would change the fuel ratio
On one hand typically LT headers will make it run RICHER---and more incoming air maybe leaner--so it's a wash-----The only true way to know exactly where you are on fuel--is to put it on a wideband---No guessing---
I would be more concerned about the timing----A stock LS tops out at about .68 grams per cylinder at WOT---so after that the timing on a stock tune goes down---With better heads it now may go up to .74 grams ---so you have to make sure your timing now is the same past that and extends to that area--
On one hand typically LT headers will make it run RICHER---and more incoming air maybe leaner--so it's a wash-----The only true way to know exactly where you are on fuel--is to put it on a wideband---No guessing---
I would be more concerned about the timing----A stock LS tops out at about .68 grams per cylinder at WOT---so after that the timing on a stock tune goes down---With better heads it now may go up to .74 grams ---so you have to make sure your timing now is the same past that and extends to that area--
Last edited by tblu92; 03-16-2015 at 01:42 PM.
03-15-2015, 06:58 PM
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I appreciate the insight. I have a WB o2 sensor hooked up with EFI live. I will end up logging to figure out what it is doing and fixing from there. A little nervous on the software end up am very familiar with it, just never implemented.
03-15-2015, 10:02 PM
#9
Drifting
Will definitely benefit from adjusting the tune. Anything that flows better will require adjustment. It's possible the fuel trims could adjust but I personally look for fuel trims under 5-7% when tuning.
03-16-2015, 01:47 PM
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St. Jude Donor '13-'14-'15
"just before going to WOT" will be added to your WOT fueling as well as a safety factor-- make the WOT fuel pig rich and engine lazy----A negative fuel trim however will never subtract fuel at WOT but will lock on "0" Typically you need to dial the trims in up to around 4000 RPM or more specific up to around 6500-7000 on your MAF HZ table---
03-16-2015, 01:48 PM
#11
Team Owner
Fuel trims don't adjust WOT (besides the + like said above).
But Maf flow does. If the heads flow more, maf will read higher as more air will move by it, and car will add more fuel. So as long as the maf tuning is decent, shouldn't be an issue. Wouldn't hurt to check and log, but if tune was good before, should be good now.
But Maf flow does. If the heads flow more, maf will read higher as more air will move by it, and car will add more fuel. So as long as the maf tuning is decent, shouldn't be an issue. Wouldn't hurt to check and log, but if tune was good before, should be good now.
03-18-2015, 08:51 PM
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Fuel trims don't adjust WOT (besides the + like said above).
But Maf flow does. If the heads flow more, maf will read higher as more air will move by it, and car will add more fuel. So as long as the maf tuning is decent, shouldn't be an issue. Wouldn't hurt to check and log, but if tune was good before, should be good now.
But Maf flow does. If the heads flow more, maf will read higher as more air will move by it, and car will add more fuel. So as long as the maf tuning is decent, shouldn't be an issue. Wouldn't hurt to check and log, but if tune was good before, should be good now.
03-24-2015, 11:21 PM
#13
Burning Brakes
Assuming VE is active that will definitely require adjustment. The maf should adjust for the changes if the intake system wasn't changed but you should definitely check it.