BP5A/MSM Intake Cam Swap Dyno Results

[—RotorNutFD3S—]

For some time it has been stated that the BP5A (aka MazdaSpeed Miata) Intake Cam would gain a few horsepower over the stock intake cam in the 99-00 Miata head in a naturally aspirated platform, but as far as I know no one has ever posted any definitive data to back that up. At least not without other changes being made at the same time which messes with the results. This past weekend at a local Dyno Day I was asked to perform this cam swap on a local forum member's Miata. The car was put onto the rollers for three pulls, I did the cam swap, and then it went back on for three more pulls. Each set of pulls were consistent and we used the highest pull from each set.

The car is a '96 with a complete '00 engine, it has an RPM switch for the VICS, a DDMWorks intake filter w/ heat shield, stock '96 exhaust manifold, high-flow cat, and a 2.25" cat-back exhaust.

The gain we recorded with the BP5A cam was 3.84 hp and 2.85 ft.-lbs. tq.:



So if you have a 99-00 Miata, or a 99-00 head or solid lifters in your earlier 1.8L and you plan on staying n/a, there is some horsepower to be had here without any other required changes. Other improvements such as a better exhaust manifold, intake, etc. will help this power curve go up further.

What I'd like to do next is take the stock 99-00 intake cam and install it into an MSM and see how it performs there, with the necessary before and after dyno pulls.

[concealer404]

FM swapped a normal cam into an MSM and recorded a gain. The theory is that the MSM cams were as such for emissions reasons, not necessarily power.

[VagaXt]

OP, thanks for the data.

FM swapped a normal cam into an MSM and recorded a gain. The theory is that the MSM cams were as such for emissions reasons, not necessarily power.

Here is the thread related to the mentioned test.

http://forum.miata.net/vb/showthread.php?t=423014

Part of the choice by Mazda for the BP5A in the MSM, rather than the normal 99 cam, is for emissions. However, you have to remember that when Jeremy at FM did the dyno test (according to the thread), he only swapped cams but not the cam gears to make an apple vs. apple comparison. One thing that was later mentioned by Emilio later in the thread was that the MSM intake cam gear is not the same as the normal 99 intake cam gear. In fact, it is the 99 intake cam gear is advanced 2 degrees compared to the MSM intake cam gear.

What I saw in the FM test is that the BP5A cam allowed more air in the combustion chamber. With Jeremy mentioning a bit of knock on the BP5A portion of the test and that he didn't change the tune after the swap, I can guess that the dyno tune was optimized and aggressive for the 99 intake cam, so it was not optimized for the BP5A cam.

[concealer404]

Ahhhhhh neat, thanks!

[atlnb]

that was a good event. i've never seen a back to back comparison either so it was about time. Eric did my cam install too, good guy to know and work with if you're local.

[—RotorNutFD3S—]

Had to edit/correct the first post. This is why:

Well guys, there is something that needs to be addressed. Yesterday, I was working on getting a before/after dyno plot on one graph to truly show the powerband difference between the two cams when something caught my eye. Sometime during the runs on Saturday, the correction factor was changed from SAE to STD which has an impact on the numbers. I've provided the dyno graph in STD CF showing the actual difference between the cams. I apologize for this small but noticeable mistake. Neither Chris nor I made this change on Saturday so we didn't think to check the CF.

Even though we didn't make the 5.78whp/4.76wtq we originally thought, this is the reaction from the owner:

My impressions... I'm a glass half empty kinda guy and (older) slightly skewd and cynical and I would have been OK with 0 gain. I have been driving the car for 3 days now ~ 24 miles rt (round trip) to work and I have to say I am not blown away but I am close. The torque when accelerating is "like a different car"... it just pulls harder period and is a blast to drive. Well worth the effort!

He's likely picking up a JR header in the next few days, so that will help things a lot too.

[wannafbody]

A flat top intake manifold may let it breathe better for more HP up top.

[etikoner]

I got a 99 exhaust cam for an ex-in cam swap in a 99 head. Here's to hoping I'll see some gains haha.

[SM16RMSM]

Interesting since I have a MSM.

[mini_fd]

want to switch cams? well do it together?

[atlnb]

Interesting since I have a MSM.

want a 99-00 intake cam?

[AndrewTCM]

lol everyone is jumping on the msm owners

[mini_fd]

Yeah back off i found the prey first and he lives nearby

[SM16RMSM]

lol everyone is jumping on the msm owners

Y me?

I would like to see is the 99 intake cam would make more power on a MSM head and motor. I want to see dyno results there. I will wait to see what Rotor Nut finds out when he gets the dyno results. I always thought the intake cam on the MSM and 99 motors the same. I know the 99 head had more lift to it compared to a standard 1.8L cam. But I never thought it was advanced 2 degrees more. It just sums it up why 99 Spec Miata is faster on tracks compared to my 94 Spec Miata. More of a reason to go out and buy myself a 99 to be competitive.

As for those guys who want to do a cam swap, I going to wait and see what I find out.

[mini_fd]

I already know there are gains when an advance timing wheel is placed to trick the crank sensor but what do you suppose the gains will be after the msm cam install plus the 5 degree advanced timing wheel installed are?