Are heads a waste with a blower?
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From: Valrico, Florida
Are heads a waste with a blower? Mellow made a comment in another thread that you do not need to spend the money on heads if you are going forced induction.. What do you guys think? Heads or just increase the boost?
Re: Are heads a waste with a blower? More air = more hp = faster. That fact doesn't change because you have a supercharger. If someone says otherwise then they don't know anything about engines.
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From: Chi-Town, IL
Re: Are heads a waste with a blower? Heads will get you a big increase, lots more flow, might drop you some PSI, but thats why you increase.. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
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From: College Station, Tx
Re: Are heads a waste with a blower? You won't be moving any more air though - NA your intake CFM is unlimited, but your pressure is fixed (1atm) - hence reduce restriction and you increase your flow.
With a compressor your CFM is fixed, but your boost is variable - reduce restriction and you flow the same CFM but at a lower pressure.
Now this is still good - lower restriction = less pumping losses = more horsepower. lower restriction also leads to lower air intake temps which allow for either more power or at least less detonation/pre-ignition issues.
Heads aren't *nearly* as vital on a FI car as they are on a NA car, but they definitely help still to make more power/make the setup more reliable.
Chris Bennight
With a compressor your CFM is fixed, but your boost is variable - reduce restriction and you flow the same CFM but at a lower pressure.
Now this is still good - lower restriction = less pumping losses = more horsepower. lower restriction also leads to lower air intake temps which allow for either more power or at least less detonation/pre-ignition issues.
Heads aren't *nearly* as vital on a FI car as they are on a NA car, but they definitely help still to make more power/make the setup more reliable.
Chris Bennight
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From: Centrifugal City
Re: Are heads a waste with a blower? haha, LOL.. you know my reply.
I mean, heads for forced induction are better of course, but are they worth the money spent? Most likely not to me unless you are increasing the cc's to lower the C/R or are moving to a 6L/LS6 style head and/or doing some exhaust port work.
You just want to see me get flamed more. LOL
<img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
Depends how much power you are after too and how much boost you are seeing. I think 600rwhp is possible with stock heads and all other mods keeping boost at 12psi tops. If you want more than that, definitely do the heads. All depends what you are after.
550rwhp and below? Not needed unless you want to lower C/R. Balancing act for rwhp above that. I'd go with the cheapest route if doing heads for cc work and mild exhaust. Stock valves.
I've owned 3 sets of hogged out tuner heads and I didn't like any of them. I know 2-3 H/C cars disappointed with their results vs. every happy dyno H/C car hitting 410+rwhp NA.
I mean, heads for forced induction are better of course, but are they worth the money spent? Most likely not to me unless you are increasing the cc's to lower the C/R or are moving to a 6L/LS6 style head and/or doing some exhaust port work.
You just want to see me get flamed more. LOL
<img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
Depends how much power you are after too and how much boost you are seeing. I think 600rwhp is possible with stock heads and all other mods keeping boost at 12psi tops. If you want more than that, definitely do the heads. All depends what you are after.
550rwhp and below? Not needed unless you want to lower C/R. Balancing act for rwhp above that. I'd go with the cheapest route if doing heads for cc work and mild exhaust. Stock valves.
I've owned 3 sets of hogged out tuner heads and I didn't like any of them. I know 2-3 H/C cars disappointed with their results vs. every happy dyno H/C car hitting 410+rwhp NA.
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From: Centrifugal City
Re: Are heads a waste with a blower? Just teasing ya.
Depends on your budget too. The amount of money I've spent on my car is sick and I hate wasting it anymore, esp on snake oil claims.
What's your goal rwhp?
For an SC, u thinking about gears?
I have about 175 miles on my 3.90's. Looking forward to getting on it and seeing how well my 335's hook up.
If I would have never spent the money on 2 H/C setups + install I could have bought a nice forged stroker right off the bat.
Depends on your budget too. The amount of money I've spent on my car is sick and I hate wasting it anymore, esp on snake oil claims.
What's your goal rwhp?
For an SC, u thinking about gears?
I have about 175 miles on my 3.90's. Looking forward to getting on it and seeing how well my 335's hook up.
If I would have never spent the money on 2 H/C setups + install I could have bought a nice forged stroker right off the bat.
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Re: Are heads a waste with a blower? Well here is my experience. I was putting out 576RWHP & 530RWTQ with stock heads and 01 LS6 cam. I was seeing between12-13 lbs of boost.
I changed out to stage III heads and 02 LS6 cam.
Strapped it on the dyno. Put down 573 RWHP and 532RWTQ. And boost dropped to 8-9 psi. So I have $3000 lumps of aluminum to reduce boost by 4 psi. <img border="0" alt="[barf]" title="" src="graemlins/gr_barf.gif" /> .
SJH tried to tell me that would happen. It's not that I didn't believe him, I just don't like theorys. His proved true. But I also have my blower maxed out.
I changed out to stage III heads and 02 LS6 cam.
Strapped it on the dyno. Put down 573 RWHP and 532RWTQ. And boost dropped to 8-9 psi. So I have $3000 lumps of aluminum to reduce boost by 4 psi. <img border="0" alt="[barf]" title="" src="graemlins/gr_barf.gif" /> .
SJH tried to tell me that would happen. It's not that I didn't believe him, I just don't like theorys. His proved true. But I also have my blower maxed out.
Thread Starter
Joined: Nov 2001
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From: Valrico, Florida
Re: Are heads a waste with a blower? My goal is 650rwhp.. I think someone needs to switch to the T-Trim blower to unmax his current setup to get those #'s up and to utilize those heads.. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
<small>[ February 05, 2003, 12:52 AM: Message edited by: VINCE ]</small>
<small>[ February 05, 2003, 12:52 AM: Message edited by: VINCE ]</small>
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From: College Station, Tx
Re: Are heads a waste with a blower? Is your blower past max impeller speed already, or are you just there?
What were the differences in your IAT's? Did you check to see if you could use more timing now if said IAT's were cooler?
But yeah, that is essentially what will happen (though I would expect after "optimizing" you would pick up 10-15rwhp with the new heads.)
Chris
What were the differences in your IAT's? Did you check to see if you could use more timing now if said IAT's were cooler?
But yeah, that is essentially what will happen (though I would expect after "optimizing" you would pick up 10-15rwhp with the new heads.)
Chris
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From: Evansville, IN
Re: Are heads a waste with a blower? We have a guy in our car club that was running the vortech 9# charger and he was at 395 rwhp and 374 rwtq on a mustang dyno. With the addition of a Thunder Racing 224/227 114 LSA cam and head work he got 475 rwhp and 450 rwtq on the same dyno. Pretty good increase. Both numbers are fully tuned.
The stock boost was around 8 at WOT, and after the heads and cam dropped into the 5-6 range.
These are stock valved ls1 heads. I am not sure but I doubt if they had a valve job or milling done to them.
The stock boost was around 8 at WOT, and after the heads and cam dropped into the 5-6 range.
These are stock valved ls1 heads. I am not sure but I doubt if they had a valve job or milling done to them.
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From: Centrifugal City
Re: Are heads a waste with a blower? It's hard to tell the Cam gains from the Head gains. I def like cams for the LS1 346 & FI.
As your boost gets higher around 12psi+ you need to flow more to drop the boost level and reduce charged air temps.
As your boost gets higher around 12psi+ you need to flow more to drop the boost level and reduce charged air temps.
Re: Are heads a waste with a blower? So if you purchased a set of 6.0L heads and had the heads chambers opened to 73cc to drop compression and left the stock 6.0L valves, replaced the valve springs, retainers, pushrods, and add a cam would that work?? Nothing else done but the chamber size increased to drop compression. Would that be a good idea over stock heads and cam??? Just thinking.
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From: Chi-Town, IL
Re: Are heads a waste with a blower? That would give you 9.5:1 compression, but if you get 6.0L get S2's with the 73cc chamber...
S2's will have bigger valves..
I'm going to find out soon, how much a full point in compression drop effects PSI..
I made 470rwhp and 540rwtq @6psi, this was with an 8lb pully...MTI S2 2.055/1.60 valves, FLP longtubes, SLP 85mm MAF, stock TB...214/218 .540/.550 114 cam...with 10.5:1 compression, and it popped a head gasket, so off come the heads..
Now TEA S2 5.7L 73cc chamber heads are being put on, 9.5:1 compression, hopefully I don't drop to like 4psi...
S2's will have bigger valves..
I'm going to find out soon, how much a full point in compression drop effects PSI..
I made 470rwhp and 540rwtq @6psi, this was with an 8lb pully...MTI S2 2.055/1.60 valves, FLP longtubes, SLP 85mm MAF, stock TB...214/218 .540/.550 114 cam...with 10.5:1 compression, and it popped a head gasket, so off come the heads..
Now TEA S2 5.7L 73cc chamber heads are being put on, 9.5:1 compression, hopefully I don't drop to like 4psi...
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Re: Are heads a waste with a blower? If your motto is: "Power at all costs", then ported heads are good for FI. But, and there IS a "but", ported heads yield diminishing returns on an FI application, since part of the efficiency increase with FI is that head flow inefficiencies are minimized by FI.
The question is: "Is the money well spent at the level you wish to attain?"
Ported heads are always a good option, but they won't yield as significant of a result with FI, especially considering the superior flow characteristics of the LS1/6 head. That is, UNLESS unlimited intake pressure is available (mainly by reinforcing the shortblock), in which case it's, again, a good capital venture.
SC-
The question is: "Is the money well spent at the level you wish to attain?"
Ported heads are always a good option, but they won't yield as significant of a result with FI, especially considering the superior flow characteristics of the LS1/6 head. That is, UNLESS unlimited intake pressure is available (mainly by reinforcing the shortblock), in which case it's, again, a good capital venture.
SC-
Re: Are heads a waste with a blower? You can only boost up a stock motor before you run into limits.
You can build a simple motor, make more power with the motor, and then also turn up the boost. That's how I see it.
You can crank 8-9 'cooled lbs of boost thru a bonestock motor and get around 500 at the wheels. But that setup won't hit 600 at the tires it will start to fall apart.
IMHO the point to running ported heads is to 1) use it as a means to reduce compression and resultantly octane requirements, and 2) to increase engine power and reduce boost related cylinder pressure.
The balance when playing with a FI motor is balancing 1) engine power/efficiency, 2) cylinder pressure and 3) power goals.
Trying to make 700rwhp with a bonestock motor would be neat but I doubt a stock motor can take 17-18 lbs of boost. So attainees of 700rwhp would have to figure out how they want to hit the number. The game is building a motor that can take 8-20 lbs of boost and figuring out how much boost you will make your motor support.
Is there anyone thinking of doing a simple 346ci that's .010 and has off the shelf parts and who also has a supercharger pulley'd up for 18 lbs of boost. Man oh man who's that crazy. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
You can build a simple motor, make more power with the motor, and then also turn up the boost. That's how I see it.
You can crank 8-9 'cooled lbs of boost thru a bonestock motor and get around 500 at the wheels. But that setup won't hit 600 at the tires it will start to fall apart.
IMHO the point to running ported heads is to 1) use it as a means to reduce compression and resultantly octane requirements, and 2) to increase engine power and reduce boost related cylinder pressure.
The balance when playing with a FI motor is balancing 1) engine power/efficiency, 2) cylinder pressure and 3) power goals.
Trying to make 700rwhp with a bonestock motor would be neat but I doubt a stock motor can take 17-18 lbs of boost. So attainees of 700rwhp would have to figure out how they want to hit the number. The game is building a motor that can take 8-20 lbs of boost and figuring out how much boost you will make your motor support.
Is there anyone thinking of doing a simple 346ci that's .010 and has off the shelf parts and who also has a supercharger pulley'd up for 18 lbs of boost. Man oh man who's that crazy. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
Re: Are heads a waste with a blower? Me I am that crazy but not 18psi crazy. <img border="0" title="" alt="[Razz]" src="gr_images/icons/tongue.gif" /> I will be building a forged 346, stock crank, 6.125 forged eagle rods, Diamond -8.6cc dished pistons. 6.0 heads. I have the 02LS1/6 block sitting in my garage waiting on the parts. I want to be pushing 15psi max out of it. But will probably run 12psi on a daily basis like the post above. If harlan can do, I can get to my goal of 600+rwhp with the above setup.
J <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />
J <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />