Page 1 of 1

Purple cam questions?

Posted: June 23rd, 2017, 7:52 pm
by GASnBRASS
Interested in using the Mopar purple cam P4529229 in my 4.0 stock rebuild. Primary needs are main power band between 2000-4000 rpm, smooth idle, good torque for low rpm crawling (32RH), and use 87 octane fuel. Have been reading tons about valve duration, overlap, lift, dynamic compression etc. Planning to use a cloyes adjustable double roller that has -4, 0, and +4 settings for the cam.

Questions are:
Is the purple cam compatible with a '98 TJ ECM?
Is the extra lift ok with the stock valve springs?
Would it be suitable for low rpm torque and mid range cruising power (3000 rpm)
Is there an ideal setting on the cam gear to advance or retard it?

The DCR is pretty close for both: stock 7.47 vs purple cam 7.56
These are the stock and purple cam specs:

Intake Duration 253 / 248
Exhaust Duration 259 / 248

Intake @ .050" 188 / 202
Exhaust @ .050" 190 / 202

Valve Lift (Intake) .408 / .440
Valve Lift (Exhaust) .414 / .440

Intake Opens @.050(BTDC) -16 / -7
Intake Closes @.050(ABDC) 24 / 29
Exhaust Opens @.050(BBDC) 20 / 29
Exhaust Closes @.050(ATDC) -10 / -7

Advertised Intake Opens (BTDC) 12 / 16
Advertised Intake Closes (ABDC) 61 / 52
Advertised Exhaust Opens (BBDC) 50 / 52
Advertised Exhaust Closes (ATDC) 29 / 16

Valve Overlap deg (advertised) 42 / 32
Lobe Separation Angle deg 108 / 108
Intake Centerline Angle deg 110 / 108

Re: Purple cam questions?

Posted: July 3rd, 2017, 11:09 am
by gradon
Run it