Ported Heads with FI?
Ported Heads with FI? Hi guys; I've been lurking in this section for a while and I'm starting to think a blower may be a good way to go for my car. I'm still running stock heads, so I'm thinking of ordering some 6.0L heads, but I'm wondering how important it would be to have them ported as well, or would porting just be a waste on a blower set up?
You will notice little or no gain because of the ported heads unless they drop your CR a little and you can put more boost. If a car is running say 10# of boost and you put ported heads on it you may only see 8# now. The blower is still pumping out the same amount of air. The heads are just moving it more efficiently. I have talked with several people about it including MTI (admiting they are not huge on blown cars I just happened to be there and asked about it.)and cars they may have done testing on and they confirmed this from their experience. So I don't know what to tell you about the ported heads except what I know. And this is it I don't know if you use ported head if you can run more bost because the boost drops. I don't think that would change the fact that you would be putting more air/fuel on a stock bottom end (Me any ways) and raising the cylinder presure and possibly lifting heads or blowing head gaskets?? May be some one else can share their expirence with this and what happens ETC... I am wanting to know this also but I haven't gotten around to asking if any one knows for sure and not just guessing.
Would you be doing a cam at the same time?
PRO: Ported 6.0 heads will flow more than stock LS1 heads
PRO: Make the engine more setup for FI
CON: Slight drop of compression going from 67cc head to 70cc head
CON: Cost might outweigh gains
But I say look at Noyzee's turbo setup, 132mph in probably a 3400 raceweight M6, he's got 6.0 heads and cam, and he's flying.
PRO: Ported 6.0 heads will flow more than stock LS1 heads
PRO: Make the engine more setup for FI
CON: Slight drop of compression going from 67cc head to 70cc head
CON: Cost might outweigh gains
But I say look at Noyzee's turbo setup, 132mph in probably a 3400 raceweight M6, he's got 6.0 heads and cam, and he's flying.
Originally Posted by Inspector12
You will notice little or no gain because of the ported heads unless they drop your CR a little and you can put more boost. If a car is running say 10# of boost and you put ported heads on it you may only see 8# now. The blower is still pumping out the same amount of air. The heads are just moving it more efficiently. I have talked with several people about it including MTI (admiting they are not huge on blown cars I just happened to be there and asked about it.)and cars they may have done testing on and they confirmed this from their experience. So I don't know what to tell you about the ported heads except what I know. And this is it I don't know if you use ported head if you can run more bost because the boost drops. I don't think that would change the fact that you would be putting more air/fuel on a stock bottom end (Me any ways) and raising the cylinder presure and possibly lifting heads or blowing head gaskets?? May be some one else can share their expirence with this and what happens ETC... I am wanting to know this also but I haven't gotten around to asking if any one knows for sure and not just guessing.
i disagree with that. if everything stays the same except for better flowing heads, you will make more power because there is less of a restriction.
alot of people dont understand this though, they think that if they have stock heads and cam and so on and see 15 psi they are doing good. when in all reality if they had some good heads on there and only made 10 psi the would indeed make more horsepower.
if more boost was the answer to hp we would all try to get the smallest, worst flowing heads we could get.
Last edited by blackz93; Jan 14, 2004 at 10:56 PM.
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Originally Posted by blackz93
i disagree with that. if everything stays the same except for better flowing heads, you will make more power because there is less of a restriction.
SC-
OK, thanks, guys, that's kind of what I was thinking. PSJ, I plan to stay with the TR224 114 cam I already have in the engine. This won't be a maximum effort setup; I estimate I only need about 490 to 500 rwhp to meet my goal of breaking 200 mph at Bonneville. The main reason I was going to get the 6.0L heads was to lower the compression ratio, but wondered if I should have them ported as well. Sounds like if I have them ported I could run 5 psi instead of 7 psi to meet my hp goals; does this sound right?
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Yes thats about how it works. You will need to get a set ported for boost there is a differance than just a standard heads and cam combo. I have a set of 6.0L heads sitting around here waiting to be ported to your application. Let me know if I can help.
Thanks Nate
Thanks Nate
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Nate,
OK thanks. Sounds like you are saying the porting is done differently when the flow is under positive presure rather than a vaccuum. I'm still a ways out on this one, but I'll give you call when I'm ready to roll on this. I'm also considering the AFR heads, though they would be overkill at the boost levels I'm anticipating.
OK thanks. Sounds like you are saying the porting is done differently when the flow is under positive presure rather than a vaccuum. I'm still a ways out on this one, but I'll give you call when I'm ready to roll on this. I'm also considering the AFR heads, though they would be overkill at the boost levels I'm anticipating.
Yes better flowing heads on a boosted application does make a good difference. CFMs make horsepower -not PSI. blackz93 said it well about "if more boost was the answer to hp we would all try to get the smallest, worst flowing heads we could get".
Having a lower boost number while still flowing the same amount of CFMs not only increases horsepower because of less backpressure (boost=heat=detonation -reduce this makes ability to run more boost or timing) but it also decreases the amount of horsepower that is parasitically lost from the supercharger trying to pump in more air.
Gains from ported heads on boost apps. can be just as much as the gains noticed on NA motors.
Having a lower boost number while still flowing the same amount of CFMs not only increases horsepower because of less backpressure (boost=heat=detonation -reduce this makes ability to run more boost or timing) but it also decreases the amount of horsepower that is parasitically lost from the supercharger trying to pump in more air.
Gains from ported heads on boost apps. can be just as much as the gains noticed on NA motors.
"If more boost was the answer to hp we would all try to get the smallest, worst flowing heads we could get."
That's a great quote.
If you are just looking for 500rwhp you might not want to do ported heads since you have a modest goal that can be easily hit by just huffing a stock longblock with headers.
That's a great quote.
If you are just looking for 500rwhp you might not want to do ported heads since you have a modest goal that can be easily hit by just huffing a stock longblock with headers.
Originally Posted by Pro Stock John
"If more boost was the answer to hp we would all try to get the smallest, worst flowing heads we could get."
That's a great quote.
That's a great quote.
thanks...that seems to be the popular belief with alot of folks!
I always understood it as since you have better flowing heads, and the boost drops (but the CFM is the same) that you could run more boost. Because once the boost drops, heat/detonation also goes away which allows you to run more boost or timing or whatever. Is that correct, or am I thinking wrong?
Time, you could boost a stock engine to 30 psi, but not only do you find the limits of the stock longblock you also will generate a lot of heat. By installing ported heads (with bigger valves) you improve the 'pump.'
Time2Kill, ya that is correct. Most people will throw on a smaller pulley to make up for that boost drop -escentially putting the boost number back to where it was before the heads. But now it will be putting in even more CFMs of airflow at that same boost number.
The only catch to spinning a supercharger faster and faster is that at some point you reach its 'redline' for rpms on the blower. Other than the lessening of heat buildup, most of the power comes from being able to put in more cfms at that same boost number by spinning the blower faster from installing freer flowing heads.
So yes you are correct
most people put on heads to drop the boost number to pulley back up again.
The only catch to spinning a supercharger faster and faster is that at some point you reach its 'redline' for rpms on the blower. Other than the lessening of heat buildup, most of the power comes from being able to put in more cfms at that same boost number by spinning the blower faster from installing freer flowing heads.
So yes you are correct
most people put on heads to drop the boost number to pulley back up again.
Originally Posted by Pro Stock John
If you are just looking for 500rwhp you might not want to do ported heads since you have a modest goal that can be easily hit by just huffing a stock longblock with headers.
Originally Posted by Cal
Right, that was part of my initial question. But with stock heads and stock compression ratio, is it safe to run up to 7 psi? Also at what point do I need stronger connecting rods and rod bolts?
Kyle