Newly Updated PRC LS7 CNC Heads Break 400CFM!!
06-30-2008, 09:10 AM
#41
how is the throttle response with these heads vs the 265cc runner version also offered by you guys?
you've mentioned that it should be no different than the OE LS7 heads, but does that refer to these heads (285cc?) or the 265cc version?
or in other words does the 285cc version lose *anything* vs the 265cc version or does it just flow more across the board?
thanks for the time
_
you've mentioned that it should be no different than the OE LS7 heads, but does that refer to these heads (285cc?) or the 265cc version?
or in other words does the 285cc version lose *anything* vs the 265cc version or does it just flow more across the board?
thanks for the time
_
06-30-2008, 02:17 PM
#42
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one thing i noticed is on the two engine dyno sheets the brake specific values seem a little odd to me...
how can you make more HP with less fuel at the top of the dyno pull but then make more HP down low with more fuel...
i didnt know if anyone else noticed that or if im just retarded (which is very possilbe
)
how can you make more HP with less fuel at the top of the dyno pull but then make more HP down low with more fuel...
i didnt know if anyone else noticed that or if im just retarded (which is very possilbe
)
06-30-2008, 06:14 PM
#43
LSxGuy widda 9sec Mustang
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one thing i noticed is on the two engine dyno sheets the brake specific values seem a little odd to me...
how can you make more HP with less fuel at the top of the dyno pull but then make more HP down low with more fuel...
i didnt know if anyone else noticed that or if im just retarded (which is very possilbe )
how can you make more HP with less fuel at the top of the dyno pull but then make more HP down low with more fuel...
i didnt know if anyone else noticed that or if im just retarded (which is very possilbe
)I think thats something to do with the way the fuel system was setup in the dyno. They had an eliminator pump feeding off a secondary fuel accumulator tank, so I'm not sure if that affected the results. We were tuning off their wideband. Next time I'm on the engine dyno I'll ask exactly why, but they said to not use the brake specific numbers to tune EFI setups.
06-30-2008, 08:15 PM
#44
ok enough of the B.S. lol Jason when are you guys going to release some news about that damn six bolt head I need to buy from you to complete my turbo/408/lsx build! The suspense is killin me man. Not to derail your guys' debate, but I'm interested in the 6 bolt head with the killer flow numbers on a ls7 style port! (and the killer price) Thanks Chris
07-01-2008, 12:09 AM
#45
Well now I'm confused....is this "newly updated" PRC head the 280cc version, or the 265cc version?! I remember in the old thread Jason, that you said these heads that are flowing 403 cfm at .7 lift was ONLY 3 cc's more than a stock LS7, which would put it at 268cc's. Does this mean that your website is outdated? I'd really like some clarification on this.
Thanks!
Adrian
Thanks!
Adrian
Last edited by Haans249; 07-02-2008 at 12:12 AM.
07-01-2008, 08:08 AM
#46
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I think thats something to do with the way the fuel system was setup in the dyno. They had an eliminator pump feeding off a secondary fuel accumulator tank, so I'm not sure if that affected the results. We were tuning off their wideband. Next time I'm on the engine dyno I'll ask exactly why, but they said to not use the brake specific numbers to tune EFI setups.
either way those heads are flowing some serious air for being so cheap.....
i got out of the lsx world due to new technology be very expensive... if it ever gets to the point where a normal guy can build a 800hp motor for less than $8,000 i may jump back in it...
07-02-2008, 02:46 AM
#48
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I asked in the other l92 head thread-but here goes-
whats so good about the prc ls7 head vs the standard factory vs other vendors cnc ls7 or reworked ls7 heads?
hows the csa and air speed-
i dont own a ls7 head-but i am building another 427 and might want to try a ls7 head-instead of a L92 head-
Thanks
Nick--
whats so good about the prc ls7 head vs the standard factory vs other vendors cnc ls7 or reworked ls7 heads?
hows the csa and air speed-
i dont own a ls7 head-but i am building another 427 and might want to try a ls7 head-instead of a L92 head-
Thanks
Nick--
07-02-2008, 01:20 PM
#51
So which application is he 280cc heads no good? Small cam with excellent street manners? I need my questions answered so I can place an order. Including which head these flow numbers are for.
07-02-2008, 01:27 PM
#52
If you are inclined to use their heads either one of them will produce close to the same results.
At flow numbers this high, it is more than you can use in a street car anyway. The quality of the cfm is much more important than the numbers of them.
The attributes that make a head good or not are never discussed on this board. Most of them you can't even quantify. How are you going to put into numbers if the port shape is correct?? What about the chamber design?? There is alot more to making HP than just flow numbers and port size.
BTW, Jason and the crew at TSP, I am not bashing or anything else against your heads. Nor am I trying to sell anyone elses heads. I was asked a question and I answered.
At flow numbers this high, it is more than you can use in a street car anyway. The quality of the cfm is much more important than the numbers of them.
The attributes that make a head good or not are never discussed on this board. Most of them you can't even quantify. How are you going to put into numbers if the port shape is correct?? What about the chamber design?? There is alot more to making HP than just flow numbers and port size.
BTW, Jason and the crew at TSP, I am not bashing or anything else against your heads. Nor am I trying to sell anyone elses heads. I was asked a question and I answered.
07-02-2008, 06:13 PM
#53
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I asked in the other l92 head thread-but here goes-
whats so good about the prc ls7 head vs the standard factory vs other vendors cnc ls7 or reworked ls7 heads?
hows the csa and air speed-
i dont own a ls7 head-but i am building another 427 and might want to try a ls7 head-instead of a L92 head-
Thanks
Nick--
whats so good about the prc ls7 head vs the standard factory vs other vendors cnc ls7 or reworked ls7 heads?
hows the csa and air speed-
i dont own a ls7 head-but i am building another 427 and might want to try a ls7 head-instead of a L92 head-
Thanks
Nick--
Anyone?
07-03-2008, 06:54 PM
#57
Guys all we ever ship is the smaller port heads. They move about 390 cfm & work really well. We've never seen less than 30rwhp from installing these in place of factory heads.
The bigger runner head will be dyno tested on a ls7 454 shortly. I'll let you guys know if it's worth the extra port size on the dyno.
The bigger runner head will be dyno tested on a ls7 454 shortly. I'll let you guys know if it's worth the extra port size on the dyno.
__________________
Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
07-03-2008, 06:57 PM
#58
Agreed Stang's Bane there is more to a port than flow & port size. That's why dyno results are the best way to prove a cylinder head works well. If you want independent dyno data talk to MTI, Quality Motorsports, Wongs Performance & several other vendors that has dyno tested the ls7 heads & seen the 30+rwhp they make over stock heads.
I've got plenty of engine & chassis dyno sheets you can look at also.
Jason
I've got plenty of engine & chassis dyno sheets you can look at also.
Jason
If you are inclined to use their heads either one of them will produce close to the same results.
At flow numbers this high, it is more than you can use in a street car anyway. The quality of the cfm is much more important than the numbers of them.
The attributes that make a head good or not are never discussed on this board. Most of them you can't even quantify. How are you going to put into numbers if the port shape is correct?? What about the chamber design?? There is alot more to making HP than just flow numbers and port size.
BTW, Jason and the crew at TSP, I am not bashing or anything else against your heads. Nor am I trying to sell anyone elses heads. I was asked a question and I answered.
At flow numbers this high, it is more than you can use in a street car anyway. The quality of the cfm is much more important than the numbers of them.
The attributes that make a head good or not are never discussed on this board. Most of them you can't even quantify. How are you going to put into numbers if the port shape is correct?? What about the chamber design?? There is alot more to making HP than just flow numbers and port size.
BTW, Jason and the crew at TSP, I am not bashing or anything else against your heads. Nor am I trying to sell anyone elses heads. I was asked a question and I answered.
__________________
Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
