Tuning after adding Ported Heads
TECH Regular
Joined: Nov 2001
Posts: 455
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From: Houston, TX USA
Re: Tuning after adding Ported Heads With a purely MAF based car (or virtually) the engine management is going to be much more adaptable than a older MAF/MAP hybrid (LT1) or MAP (speed Density) vehicle. You really don't need to make as many changes.
It's pretty tough to say "for xxx mod do yyy" - 2 sets of ported heads - one kills cylinder pressure below 3000 rpm and increases it above, the other increases cylinder pressure from 2000-5000, then runs out of breath - they are going to have different timing/fuel requirements - yet they are both "ported heads".
You can't really tune based on mods - it's better to look at the car individually an tune based on empirical data (logs, track times, dynos, etc.)
It's pretty tough to say "for xxx mod do yyy" - 2 sets of ported heads - one kills cylinder pressure below 3000 rpm and increases it above, the other increases cylinder pressure from 2000-5000, then runs out of breath - they are going to have different timing/fuel requirements - yet they are both "ported heads".
You can't really tune based on mods - it's better to look at the car individually an tune based on empirical data (logs, track times, dynos, etc.)
Re: Tuning after adding Ported Heads Chris ARE 360,
I don't have flow numbers. I was too anxious to get the car back together. Here is what I can tell you about the porting I did.
Intake runner stayed about the same as stock cross section, just cleaned up and smoothed castings. I streamlined the valve guides bosses and removed the rocker bolt boss until it broke through, effectively straightening the wall where the boss hump was. I opened the port walls slightly to the sides of the guide boss. Short side radius, no changes other than removing rough casting and blending bowl to seat.
Cleaned up the bowl area and blended into the seat. Machine shop performed three anlge valve job and installed 2.02 and 1.55 Ferrea vavles. Milled heads 0.030, chambers cc'd out to 63 cc.
Intake port cc'd to 214 cc. Stock 6.0L is 210 cc.
Stock 5.7 is 200 cc for comarison.
I guess you could say my heads are similar to Stage 1.
The car didn't seem to loose much if any bottem end (idle - 2.5 k). Picked up some midrange and top end. The dyno will tell a better story.
SpeedDemon,
You are correct, and good info for me too. Purely depends on the heads. I really need some Atap numbers and wideband O2's at the dyno.
When you say heads "kill cylinder pressure" would that mean hogged ports out with crapped velocity?
"Increase cylinder pressure", great velocity with optimal cylinder filling at low rpms? This would be me.
I am learning here.
Thanks,
Brandon
I don't have flow numbers. I was too anxious to get the car back together. Here is what I can tell you about the porting I did.
Intake runner stayed about the same as stock cross section, just cleaned up and smoothed castings. I streamlined the valve guides bosses and removed the rocker bolt boss until it broke through, effectively straightening the wall where the boss hump was. I opened the port walls slightly to the sides of the guide boss. Short side radius, no changes other than removing rough casting and blending bowl to seat.
Cleaned up the bowl area and blended into the seat. Machine shop performed three anlge valve job and installed 2.02 and 1.55 Ferrea vavles. Milled heads 0.030, chambers cc'd out to 63 cc.
Intake port cc'd to 214 cc. Stock 6.0L is 210 cc.
Stock 5.7 is 200 cc for comarison.
I guess you could say my heads are similar to Stage 1.
The car didn't seem to loose much if any bottem end (idle - 2.5 k). Picked up some midrange and top end. The dyno will tell a better story.
SpeedDemon,
You are correct, and good info for me too. Purely depends on the heads. I really need some Atap numbers and wideband O2's at the dyno.
When you say heads "kill cylinder pressure" would that mean hogged ports out with crapped velocity?
"Increase cylinder pressure", great velocity with optimal cylinder filling at low rpms? This would be me.
I am learning here.
Thanks,
Brandon
Tuning after adding Ported Heads I just added 6.0L ported heads, mildly ported (by me). See sig for other mods.
How do ported heads usually affect our cars A/F ratio. Do they tend to lean the car then it over compensates to make it rich? I know it smells richer at idle. And I get black smoke out the exhaust when I stand in it.
Does anyone have a tuning guide? What to look for with Atap? What is the ideal set up?
I would really like to understand completely how the cars computer adjusts to compensate for mods.
I have a general idea from reading info on the boards and other sites, but if anyone with experience knows any tricks or trouble areas to watch I would appreciate it.
I plan to get LS1 edit soon.
For now I am stuck with Hypertech tuning.
How do ported heads usually affect our cars A/F ratio. Do they tend to lean the car then it over compensates to make it rich? I know it smells richer at idle. And I get black smoke out the exhaust when I stand in it.
Does anyone have a tuning guide? What to look for with Atap? What is the ideal set up?
I would really like to understand completely how the cars computer adjusts to compensate for mods.
I have a general idea from reading info on the boards and other sites, but if anyone with experience knows any tricks or trouble areas to watch I would appreciate it.
I plan to get LS1 edit soon.
For now I am stuck with Hypertech tuning.
