Yeah, when i ordered them, i told integral that i wanted a cam to make power to 9k on a turbo race motor. I sent them my flow sheets, and those were the cams that they recommended for me. And they did what they were designed to do.

If you look at my dyne graphs, there is no denying that they make insane power up top. I make the same power as others at 5psi less. But they took a major chunk out of my mid range. I didn't realize at the time how badly this would effect the drivability of the car on the track. For drag racing or all out dyne numbers they are the cats meow. They were making max torque at like 6500, and i revved it to 8500 and they didn't fall off.

Now that I'm putting this motor into a street car, I'm scaling down the cams a little and going with a different manifold and EFR turbo setup. My goal will be peak torque around 4500 and power to 8000. I should be able to get that with durations around 220@.05 and lift in the .425+ range.

 

CT: Interested to see how that fairs for you; I'm considering cams for the exact same RPM range.

 

Ehh you won't be seeing it from me, a few weeks ago a made the decision to scrap any plans for BP power in favor of the new K24 swap. Unless those guys fall through with a final kit. I will be selling my BP engine.

 

I'm rebuilding my engine soon and getting a shopping list of parts.
It's a sprint/ hillclimb familia gtx with aftermarket AEM EMS 4 management.
My block will be all new with 9-1 comp.
I've got hold of a bp 4 w head, now what do i do and how far shall I go? I've not got an unlimited budget but I'm not scrimping either.
There are so many options,I can get it ported for £900 which increases flow by 20% (CNC heads. Uprated springs are a must for any increased rpm increase.
Do I keep the standard cams and get adjustable cam wheels.
Do I get a full set of cat cams/real street and forget the porting?

I don't want massive pub bullshit horsepower,I need good power all through the rev range,I can use anti lag if need be as the sprints are only short.
Decisions decisions

I've e mailed the my tuner to see what he thinks but waiting for his reply.

 

For sure port the head. You can add cams later. It's harder to port the head at a later date. I would suggest you reach out to Kiel at Kelford and tell him what your goals are and that you listen very closely to his answers. And buy his valve springs. They are by far the best springs on the market for the Miata. If you do get his springs and want a set of Titanium retainers to fit them let me know....I'll make you a set.

 

Like TNTUBA says, if you can afford the port work, do it. BP motors wake up substantially with port work and good induction. Even with a small cam.

 

+10.

The casting inside the ports is so terrible. Casting flash in my intake valves was so bad it cut my finger when inspecting them. I just finished porting my head, and polishing up the chambers and it was a most major PIA. Easily worth paying for if you value your time.

 

I'm not saying you shouldn't port the head, but you're not gonna see a 20% increase in flow from port work. 10ish on stock cams and if you go up around the .400" lift mark you're looking around 15%.

 

The biggest improvement is moving to a BP4W instead of the older BP head.
In my build thread there are numbers for a ported BP6D head (my engine guy said "a little nicer casting than the BP4W"). If you want numbers at 28" water, just multiply by 1.67.
10-14% on the intake when moving to a 34mm valve (looking at the 8-10mm lifts, +22% at 1mm lift)
4-7% on the exhaust using stock sized 28mm valve (not much work was done, arguing that N/A doesn't make use of that high exh flow, which others have prooved it can, e.g. 949 CNC with 30mm exh valves).

 

Yes, Going to bigger valves in addition to a full port job can get you 15-20% total over stock.

 

There are pretty good gains from porting the exhaust side. The bp4w castings iv worked on are almost flat on the sides of the exhaust ports. Its really not much better on the intake side with the big casting shifts as well.

 

So a BP4W head should flow 250 cfm with a port & polish, +1mm valves and 10mm lift cams.

 

Lower your expectations to 240ish and you will not be that disappointed.
I know mine flows a little less than some others, but everyone doesn't have access to Voodoo priests.

 

That kind of depends. Some shops report cfm @25" of water, but the standard is considered 28". You can convert whatever reading the shop reports by looking at a conversion table.

Rebello tested my head and reported 235 cfm @.500" lift, but it was tested or reported @ 25" of water. Multiplying the cfm by 1.06 converts it to the standard 28", which equals 249 cfm.

 

Are you actually running 12.7mm lift cams?

 

it also depends on what kind of flow bench you use. sorta like dynos, they all read different from model to model.

 

No I am not. Good point though.

I believe 0.450" or 0.500" is used when comparing one head from another. Particularly when comparing totally different makes and models. At least that is what I see posted most of the time.

Mine was tested in 0.100" increments, with the lowest lift at 0.050"

 

248 @ .400 at 28" with +1mm valves

 

I'm currently running 330bhp at the flywheel with an N/A head GTR cams,although this engine has been burning more oil as the season went on so i'm builing up my spare GTR engine, i wil be keeping my VJ23 for the time being but plan on upgrading to a better turbo,manifold,exhaust and intake in the future when i have a few more pennies.
Building the bottom end is the easy bit, the top end is far more difficult with so many variables and a lot more cost!
I want the holy grail of power,a broad power band, i can use anti lag for low end. I do sprints and hillclimbs and the occasional track day,i dont drag race so i dont want all top end big bhp power as thats just pointless for me.
Here is the link to the CNC head site
Mazda MX5 1.6-1.8-2.0L | CNCHeads

OR do i just rebuild the bottom end,then just slap on the BP4W head on as it is (are the cams are better than gtr ones?) and out of interest just see what improvement that makes alone? it would be quite interesting to see the difference.
After all,as well as builing the engine,ive got to get a new flywheel made to suit my new 7.25 twin plate clutch and buy a set of super sticky slick tyres for the up and coming season.
In all fairness i did well last year,so more power is just somthing i want rather than need.

OR just say F**k it and do the lot,hammer the credit card.

 

how much more fuel u guys use with cams instereted to knw