FI head decisions
FI head decisions Before I make a $$$ mistake, lets get some clarification from all the air pump experts.
I am getting conflicting info on the pro's and con's of high dollar Vs econo heads in forced induction (procharger) applications.
While absolute flow is a consideration, I don't want to be giving up too much torque in the normal "cruising" mode of operation.
So lets get to the chase. given that I currently have a set of OEM bone stock 241 castings.....anything will be an improvement. That being said someone explain to me the difference between a PRC or PP ported head flowing 307 CFM @ .600 and an ETP or AFR flowing roughly the same????
What driveability issues in the lower RPM bands??
HP / TQ differences for given RPM settings??
I am getting conflicting info on the pro's and con's of high dollar Vs econo heads in forced induction (procharger) applications.
While absolute flow is a consideration, I don't want to be giving up too much torque in the normal "cruising" mode of operation.
So lets get to the chase. given that I currently have a set of OEM bone stock 241 castings.....anything will be an improvement. That being said someone explain to me the difference between a PRC or PP ported head flowing 307 CFM @ .600 and an ETP or AFR flowing roughly the same????
What driveability issues in the lower RPM bands??
HP / TQ differences for given RPM settings??
TECH Fanatic
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Flow isn't everything. The velocity of the heads is important as well. I'm not sure what the difference in velocity is between the heads you listed but I know the the deck is thicker on the AFR's and ETP's. A thicker deck can be useful under higher boost levels because the heads will resist lifting off of the block.
...HP and TQ output will be dependant on your overall setup.
...HP and TQ output will be dependant on your overall setup.
Not looking to go exploring into the realm of unknowns......my boost levels for the time being will be around 10-11 PSI. Running that now on the stock 241 Castings.
As for flow, I have not seen anything published on the 243's offered by PRC and PP. not being an expert on the topic (obviously) I presume that it is the velocity as a result of runner size that will have the greatest impact on torque.
As for flow, I have not seen anything published on the 243's offered by PRC and PP. not being an expert on the topic (obviously) I presume that it is the velocity as a result of runner size that will have the greatest impact on torque.
Teching In
Joined: Dec 2005
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I don't know how it works in the FI world but AFRs and stock heads flowing the same @.600 lift will not always flow the same at say @.300 lift. Ive found usually the AFRs have better low end Tq. It depends on who does the porting but usually if you find someone good enough they'll cost just a little less than AFRs do anyway. Also, once you get your AFRs they can be ported further to increase the flow @ .600.
Again, I've heard that this all makes a lot less of a difference once yo've got a turbo, the gains are less. If your under 15psi, it just depends on how much less PP costs than new heads. What prices have you been quoted?
Again, I've heard that this all makes a lot less of a difference once yo've got a turbo, the gains are less. If your under 15psi, it just depends on how much less PP costs than new heads. What prices have you been quoted?
Originally Posted by Bens3rdgen
I don't know how it works in the FI world but AFRs and stock heads flowing the same @.600 lift will not always flow the same at say @.300 lift. Ive found usually the AFRs have better low end Tq. It depends on who does the porting but usually if you find someone good enough they'll cost just a little less than AFRs do anyway. Also, once you get your AFRs they can be ported further to increase the flow @ .600.
Again, I've heard that this all makes a lot less of a difference once yo've got a turbo, the gains are less. If your under 15psi, it just depends on how much less PP costs than new heads. What prices have you been quoted?
Again, I've heard that this all makes a lot less of a difference once yo've got a turbo, the gains are less. If your under 15psi, it just depends on how much less PP costs than new heads. What prices have you been quoted?
Teching In
Joined: Dec 2005
Posts: 40
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My 195cc AFR cost $1800 w/o shipping. I think what you really have to ask yourself is, "Am I really gonna be happy with 10-11psi." If yes, than stock will be fine, if no, than your gonna what something with a thicker deck. Just my .02
Ben
Ben
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Originally Posted by Bens3rdgen
My 195cc AFR cost $1800 w/o shipping. I think what you really have to ask yourself is, "Am I really gonna be happy with 10-11psi." If yes, than stock will be fine, if no, than your gonna what something with a thicker deck. Just my .02
Ben
Ben
At what PSi would the deck thickness really become an issue
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Originally Posted by camrsz
do the darts heads have a thicker deck?
Since you can warp a head easily if you lift them, as good insurance I'd go with a thicker deck just in case it happens.
hard to say what psi but if i had to say I'd say anything over 13 psi. :dunno:
hard to say what psi but if i had to say I'd say anything over 13 psi. :dunno:
id say unless your going all out on a race car or more than 15psi a thicker deck isnt a must.get good gaskets and heads STUDS are a must.My heads just got finished and while the AFR 205's outflow me by a few cfm's at max lift(.600) i OWN them at mid lift,which is where the valve spends more time.You dont have to spend +$2000 to get good flowing heads for a non racecar.The thicker deck is nice for high boost but unless ur detonation and/or running quite a bit of boost its not a necessity.i believe harlan ran >20psi with a normal deck head
Originally Posted by Got Me SOM
I'm probably going to go with a AFR 205 or something that ESP offers, my car's a street car so I want a lot of low end grunt.
Originally Posted by b727pic
Not looking to go exploring into the realm of unknowns......my boost levels for the time being will be around 10-11 PSI. Running that now on the stock 241 Castings.
As for flow, I have not seen anything published on the 243's offered by PRC and PP. not being an expert on the topic (obviously) I presume that it is the velocity as a result of runner size that will have the greatest impact on torque.
As for flow, I have not seen anything published on the 243's offered by PRC and PP. not being an expert on the topic (obviously) I presume that it is the velocity as a result of runner size that will have the greatest impact on torque.
Originally Posted by LANCE ATKINSON
My heads are agostinos and have 232 intake runners and made 600trq lifting @ 5krpm running out of fuel on a 347 w A small cam. I think on a blower app u can force the air in but need a good exhaust number to get it out with some big headers! So I wouldnt just forget about cfm numbers completely. Call information for cnc cylinder heads in pinellas park florida for some bad *** blower app heads!!! Only reason I have are is they were 800 bucks and new! Ask for Pete he will fix u right up!!
Originally Posted by b727pic
Not looking to go exploring into the realm of unknowns......my boost levels for the time being will be around 10-11 PSI. Running that now on the stock 241 Castings.
As was said it would probably be a good idea to get boost-specific heads with much more exhaust bias. A head with a D-port and enough meat to put in larger exhaust seats would be what I'd go for.
No not yet,still waiting for the motor to be shipped.and getting some parts.Ill be hosting pics of the heads and coated headers soon.Itll be at Rick Cranes shop,you may know him?If you want ill let you know when i have everything and you can always stop by then and see all the goodies,lol.If not im friends with Norris and he'll be tuning it so we could always meet up then.