Because CNC
08-22-2013, 04:41 PM
#61
I always find it funny that on every car forum I'm on... people expect head work info to be given away for free. Sure I could see coming at a random person for more info and raw numbers/proof. But a vendor/racer/business and miata R&D shop? Why the hell would they give the info away? If you're smart enough to provide comment and suggestions... chances are you're smart enough to get a similar result yourself and you won't be a customer. If you are that smart and you're just lazy... stfu and get your wallet out.
I always find it ironic that the biggest **** talkers in threads like this... are the people that would pretty much never be customers of said product.
I always find it ironic that the biggest **** talkers in threads like this... are the people that would pretty much never be customers of said product.
I'm on to your agenda.
Reply
0
0
08-30-2013, 08:12 AM
#69
4800-7800, cams under .420". If we were NASCAR, the port would be optimized for the track, that day.
Part of the development was in our 2012 PTE race cars class limited to 130whp with a 5 speed and 4.3 diff. To avoid being stuck between gears, we would engineer a powerband that was 4000rpm wide. That's where the focus on velocity and not peak flow came in. Just the same, we were seeing peak cfm numbers only about 20cfm shy of those quoted to us by EP and GT3 engine builders. Those guys are using half inch, 310° cams spun to 9000rpm.
Concurrent development was done on a higher power class with a narrower powerband. Eventually the various port designs iterations merged into one port design that did everything better and that's the one we had digitized. So we're very happy with the port from a bone stock engine with an ECU to a medium race engine with an 8500rpm redline.
Part of the development was in our 2012 PTE race cars class limited to 130whp with a 5 speed and 4.3 diff. To avoid being stuck between gears, we would engineer a powerband that was 4000rpm wide. That's where the focus on velocity and not peak flow came in. Just the same, we were seeing peak cfm numbers only about 20cfm shy of those quoted to us by EP and GT3 engine builders. Those guys are using half inch, 310° cams spun to 9000rpm.
Concurrent development was done on a higher power class with a narrower powerband. Eventually the various port designs iterations merged into one port design that did everything better and that's the one we had digitized. So we're very happy with the port from a bone stock engine with an ECU to a medium race engine with an 8500rpm redline.
Does that mean the power is nosing over at 7800 (shift at ~8300) or you want to shift at 7800?
Reply
0
0
08-30-2013, 09:16 AM
#70
The point is that the ports or not huge so that they flow and make power well in the ranges that most people actually use. We could of design ports that would have amazing flow numbers but not make any more power with stock or mild cams.
Reply
0
0
08-30-2013, 09:54 AM
#71
Elite Member
Join Date: Oct 2011
Location: OKC, OK
Posts: 3,693
Total Cats: 222
Emilio, do you think this head with mild cams + some compression will need a Honda manifold or ITB's to get the most up top? I remember an old post or blog post of yours indicating you thought the squaretop was responsible for a relatively flat peak on a previous engine.
Reply
0
0
08-30-2013, 10:25 AM
#72
Emilio, do you think this head with mild cams + some compression will need a Honda manifold or ITB's to get the most up top? I remember an old post or blog post of yours indicating you thought the squaretop was responsible for a relatively flat peak on a previous engine.
unless you have very specific needs for the highest peak power I strongly recommend sticking to a single throttle manifold. The square top works just fine.about a year and a half ago we made 182 whp on pump gas with an unported head and square top. big cams though.
.
Reply
0
0
08-30-2013, 05:46 PM
#73
Powerband will depend on how your particular car is setup. The BP6D cammed engine can be tuned to make good power from 4800-7400 N/A. Turbo, BP4W head, different cams, exhaust, fuel and other aspects can all vary breadth and location of power band.
The point is that the ports or not huge so that they flow and make power well in the ranges that most people actually use. We could of design ports that would have amazing flow numbers but not make any more power with stock or mild cams.
The point is that the ports or not huge so that they flow and make power well in the ranges that most people actually use. We could of design ports that would have amazing flow numbers but not make any more power with stock or mild cams.
in general terms, a single throttle maniold will have the widest power band and ITBs will have the highest peak power. Choose one.
unless you have very specific needs for the highest peak power I strongly recommend sticking to a single throttle manifold. The square top works just fine.about a year and a half ago we made 182 whp on pump gas with an unported head and square top. big cams though.
.
unless you have very specific needs for the highest peak power I strongly recommend sticking to a single throttle manifold. The square top works just fine.about a year and a half ago we made 182 whp on pump gas with an unported head and square top. big cams though.
.
And it looks, by them, like the flattop is good for 6000 and up, but loses out to the VTCS below that, which has a rather wider power band. Also, the ITBs there don't seem to give up much torque below 5000, but take off quite well anywhere above 5000.
Does that not agree with your own data? Just to my own eyes, the ITB 5000-7800/8500 powerband seems to be the best option for a wider powerband (that's high up, at least), with the VTCS below that (for a lower RPM but flatter torque curve everywhere).
Reply
0
0
08-30-2013, 06:37 PM
#74
the ports are sized for a range of cams that will make power in that rpm range. The ports themselves do not have an RPM range. shift point depends on your peak hour and your power band so I cannot answer your specific question of where you need to shift on your virtual set up.
there are Java Script calculators floating around the interweb that you can plug your power band and gearing into and get a shift point recommendation. You can do the same thing with most data acquisition systems like a racepak g2x traqmate or aim solo.
there are Java Script calculators floating around the interweb that you can plug your power band and gearing into and get a shift point recommendation. You can do the same thing with most data acquisition systems like a racepak g2x traqmate or aim solo.
Reply
0
0
09-02-2013, 01:20 PM
#75
Junior Member
Join Date: Oct 2012
Posts: 138
Total Cats: 5
This will be a great option, especially for those of us that don't have local engine builders who specialize in Miatas. Wip out the plastic and make a call... a few days later a shiny, built cylinder head shows up at the front door.
If someone thinks that is a "bad thing", it would seriously make me wonder...
If someone thinks that is a "bad thing", it would seriously make me wonder...
Reply
0
0
10-19-2013, 04:49 PM
#78
Newb
Join Date: Jan 2010
Location: wakefield UK
Posts: 20
Total Cats: 2
Similar CHC head here in Uk gave me a extra 38bhp with +1mm valves, stock cams on a 1.6 which is still being finished off once I can sort the ignition out.
Mazda MX5 1.6-1.8-2.0L | CNCHeads
Mazda MX5 1.6-1.8-2.0L | CNCHeads
Reply
0
0
10-19-2013, 09:20 PM
#79
Elite Member
Join Date: Jul 2007
Location: Houston, TX
Posts: 3,202
Total Cats: 146
Similar CHC head here in Uk gave me a extra 38bhp with +1mm valves, stock cams on a 1.6 which is still being finished off once I can sort the ignition out.
Mazda MX5 1.6-1.8-2.0L | CNCHeads
Mazda MX5 1.6-1.8-2.0L | CNCHeads
Reply
0
0
