Posts tagged "BP"

BP ExhIntake Cam Swap

Here is a 1:1 template that I made in order to redrill the cam gear.

This mod has been gaining a lot of popularity recently due to how cheap and effective it is. For me it felt like a 14 deg timing bump without actually advancing the timing. Basically what happens in the ExhIntake cam swap is the exhaust cam is installed on the intake side, then clocked accordingly. This mod is only available for NA and NB 1.8Ls due to the CAS being on the exhaust cam. In a nutshell, you obtain an exhaust cam from a 1.8L head (BP from a 1.8L Mazda Protege, 1.8L Mazda Miata, 1.8L Ford Escort GT), cut the CAS tangs off of the cam, redrill a stock cam gear to 197.5 deg off of in I tick mark (or use an adjustable one), and install. The cam specs from SoloMiata show the same amount of total lift, but the exhaust has a longer duration.

US Spec 1.8 BP
94-97 (Hydraulic Lifters)
99-00 (Solid Lifters)
Duration @
Intake (BP05)
Exhaust (BP06)
Intake
Exhaust
.010”
218
232
257
278
.020”
208
220
224
232
.040”
195
208
209
215
.050”
190
202
204
210
.080”
176
190
190
196
.100”
167
180
181
187
.150”
145
158
158
164
.200”
119
134
132
141
.250”
89
108
102
114
.300”
43
70
59
79
Valve Timing
5 BTDC
56 BBDC
8 BTDC
53 BBDC
48 ABDC
14 ATDC
49 ABDC
9 ATDC
Overlap
19 (-5-14)
17 (-8-9)
Base Circle Dia.
1.415”
1.415”
1.418”
1.418”
Total Lift
.338”
.338”
.326”
.350”

*Data taken from: http://members.aol.com/solomiata/cams.html

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4 comments - What do you think?
Posted by admin - December 25, 2011 at 6:55 am

Categories: Power Mods   Tags: , , ,