ZZ4 cam full specifications
05-31-2005, 12:41 PM
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ZZ4 cam full specifications
The ZZ4 cam always comes up in conversations here, but there doesn't seem to be a whole lot of information about it other than the .050 spec. Here's a full spec, which I think is interesting to some folks
If you use Comp Cams method the ZZ4 cam has an ADV duration of around 264/274. Crane Cams using 0.004 tappet lift for their cams. What also is notable is that this cam should probably be installed with a 4* advance instead of straight up. The opening points are very late compared to performance cams from Crane Cams, Comp Cams, Lingenfelter, etc.
The other thing to note, is duration wise this cam is very close to the 08-302-8 cam, but it has different max lifts. The ramp rates seem OK, kind of like the non-XE Comp Cams, but the intake lobe seems lazy compared to the 08-302-8 cam. The exhaust rate is about the same as the 08-302-8 cam, but with extra lift. It's hard for me to say which cam would be better, the 08-302-8 or this cam. I'd think, however, if you're heads can handle the lift of the ZZ4, you may have better choices in the 08-304-8 or the 08-501-8 cams.
The ZZ4 cam is heavily biased towards exhaust, and I'm wondering how well the stock ports and chambers on the 081/083 heads would do with this or if it would be better to stick a 1.6 rocker on the intake and keep the 1.5 on the exhaust.
The advantage of the ZZ4 cam is cheap, but one may be better off in the long run with a better cam like the 08-304-8 (266HR) or the 08-501-8 (XR264HR) when you try to make up the "deficit" on the intake lobe for the ZZ4 cam, such as getting 1.6 rockers for the intake.
I don't have enough experience with cam timing and head flow rates to say how well of a match this cam is to the stock 081/083 flow. This comes up quite often, but it's difficult for me to truly quantify the micro differences of the cam in relation to the heads (most people who pick up the ZZ4 cam look to do it on relatively stock/unported heads).
What do you all think? Would the XR264HR have too much flow for the 081/083 stock chambers/ports (assuming the valve guides are cut for the lift of the ZZ4)? How about the 08-304-8? How does this compare to the 08-302-8?
For reference, you can also get the full LPE cam specs from LPE cam.
Code:
EPI, Inc.
(Engine Performance Improvements for Diverse Vehicles)
PO Box 115, Amboy WA, 98601 360-247-5858 (FAX: 247-5859) www.epi-eng.com
February 11, 2005
ZZ-4 Cam Lobe Analysis
ZZ-4 Camshaft P/N 10185071
GM ZZ-4 Roller Hydraulic 208-316/222-340/112
PV=787-785/839-814; CV@.003:=101/083; PA=369-252-330/371-230-322
LIFT DUR. OPEN CLOSE AREA
Lobe Intake ----- ------ ----------- ----------- ------
Centerline 112.10 ATDC 0.006 264.18 16.38 BTDC 67.81 ABDC 23.04
.050 Lift C/L 112.52 ATDC 0.020 237.33 5.08 BTDC 52.26 ABDC 22.88
Runout 0.00090 0.050 208.32 8.36 ATDC 36.67 ABDC 22.39
Peak Open Acc. 0.000370 0.100 177.68 23.05 ATDC 20.73 ABDC 21.26
Peak Nose Acc. -0.000253 0.150 151.91 35.84 ATDC 7.75 ABDC 19.66
Peak Close Acc. 0.000328 0.200 125.29 49.23 ATDC 5.48 BBDC 17.32
Lift @ TDC 0.0295 0.250 93.57 65.21 ATDC 21.22 BBDC 13.74
Lobe Separation 112.1 0.300 45.47 89.25 ATDC 45.28 BBDC 7.06
Peak Velocity .00787, -.00785
Closing Velocity @ 0.003: -.00073
0.31556 --- PEAK CAM LIFT ---
0.47033 --- PEAK VALVE LIFT w/1.50 rocker---
LIFT DUR. OPEN CLOSE AREA
Lobe Exhaust ----- ------ ----------- ----------- ------
Centerline 112.10 BTDC 0.006 273.10 67.30 BBDC 25.80 ATDC 26.28
.050 Lift C/L 111.12 BTDC 0.020 249.40 55.52 BBDC 13.88 ATDC 26.12
Runout 0.00070 0.050 221.65 41.95 BBDC 0.30 BTDC 25.62
Peak Open Acc. 0.000373 0.100 191.82 27.44 BBDC 15.62 BTDC 24.48
Peak Nose Acc. -0.000232 0.150 167.24 15.38 BBDC 28.14 BTDC 22.89
Peak Close Acc. 0.000321 0.200 142.23 3.06 BBDC 40.83 BTDC 20.65
Lift @ TDC 0.0492 0.250 113.62 11.13 ABDC 55.24 BTDC 17.37
Lobe Separation 112.1 0.300 75.76 29.97 ABDC 74.27 BTDC 12.08
Peak Velocity .00839, -.00814
Closing Velocity @ 0.003: -.00072
0.34040 --- PEAK CAM LIFT ---
0.50760 --- PEAK VALVE LIFT w/1.50 rocker --- The other thing to note, is duration wise this cam is very close to the 08-302-8 cam, but it has different max lifts. The ramp rates seem OK, kind of like the non-XE Comp Cams, but the intake lobe seems lazy compared to the 08-302-8 cam. The exhaust rate is about the same as the 08-302-8 cam, but with extra lift. It's hard for me to say which cam would be better, the 08-302-8 or this cam. I'd think, however, if you're heads can handle the lift of the ZZ4, you may have better choices in the 08-304-8 or the 08-501-8 cams.
The ZZ4 cam is heavily biased towards exhaust, and I'm wondering how well the stock ports and chambers on the 081/083 heads would do with this or if it would be better to stick a 1.6 rocker on the intake and keep the 1.5 on the exhaust.
The advantage of the ZZ4 cam is cheap, but one may be better off in the long run with a better cam like the 08-304-8 (266HR) or the 08-501-8 (XR264HR) when you try to make up the "deficit" on the intake lobe for the ZZ4 cam, such as getting 1.6 rockers for the intake.
I don't have enough experience with cam timing and head flow rates to say how well of a match this cam is to the stock 081/083 flow. This comes up quite often, but it's difficult for me to truly quantify the micro differences of the cam in relation to the heads (most people who pick up the ZZ4 cam look to do it on relatively stock/unported heads).
What do you all think? Would the XR264HR have too much flow for the 081/083 stock chambers/ports (assuming the valve guides are cut for the lift of the ZZ4)? How about the 08-304-8? How does this compare to the 08-302-8?
For reference, you can also get the full LPE cam specs from LPE cam.
Last edited by 91Z28-350; 05-31-2005 at 01:07 PM.
05-31-2005, 09:08 PM
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No comments? Here I thought it would be interesting to spend more in depth detail on the ZZ4 cam and cam selection. Oh well. How about the interpretation that it should be installed with 4* advance?
06-01-2005, 01:52 PM
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Well, maybe I'm the only one, but I found it extremely interesting. I agree that it's a pretty mild cam in terms of accleration/deceleration rates, but it IS production cam and the factory does not like to "push the envelope" and beat up the valvetrain if they're holding the warranty on it! Plus modest ramps leave plenty of headroom to work just great with 1.6 rockers!
Agreed, if that spec is right, the cam is about "straight up" as judged by .050 event points. If you look at the centerline at .006" lift you'll notice it's even 4* further retarded than that. Advertised duration centerlines are typically 4* further retarded than .050 centerlines becuase modern cam lobes almost always lift the valve faster than they close them at low lift points. The ZZ-4 cam seems to fit that typical mold just like most other cams do.
That's the long way around the barn to say.... I agree you should probably consider installing the ZZ-4 cam 4* advanced at the chain for most applications. Then again, it's not a very big cam and I don't think it necessarily needs the low-mid RPM torque bump that a 4* advance would offer. Probably makes plenty of torque even without the advance so the engineers left it straight up to help "stretch" the upper RPM performance of such a short duration cam.
Thanks for posting the info
Agreed, if that spec is right, the cam is about "straight up" as judged by .050 event points. If you look at the centerline at .006" lift you'll notice it's even 4* further retarded than that. Advertised duration centerlines are typically 4* further retarded than .050 centerlines becuase modern cam lobes almost always lift the valve faster than they close them at low lift points. The ZZ-4 cam seems to fit that typical mold just like most other cams do.
That's the long way around the barn to say.... I agree you should probably consider installing the ZZ-4 cam 4* advanced at the chain for most applications. Then again, it's not a very big cam and I don't think it necessarily needs the low-mid RPM torque bump that a 4* advance would offer. Probably makes plenty of torque even without the advance so the engineers left it straight up to help "stretch" the upper RPM performance of such a short duration cam.
Thanks for posting the info
06-01-2005, 07:09 PM
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I like this stuff too. I had a used ZZ3 cam measured a while back and the date agrees very closely with what you've posted. The delayed intake timing is interesting. TPIS advanced the intake about 7 degs and exhaust about 5 degs on the ZZ9 compared the ZZ3/4. I think Damon is on to something relative to extending the usable RPM range by installing the ZZ4 straight up. I'd be tempted to install it straight up with a LTR TPI setup.
An interesting thing that the Cam Pro Plus showed was that the ZZ3 set the exhaust valve down much more gently on the seat than another street performance cam I had measured at the same time. I expect it would be quite a bit quieter and easier on the valve train, something to consider for a daily driver. I have a few more cam measurement files saved off that you might find interesting. Drop me an email if you'd like a copy.
The XR264HR should make an awesome LTR TPI cam. I'd even be tempted to have a custom cam ground that combines the intake lobe of the XR264HR with the exhaust lobe of the XR270HR if running the stock 083 heads since the exhaust flow of these heads is so bad. You basically end up with a slightly hotter ZZ9 clone.
An interesting thing that the Cam Pro Plus showed was that the ZZ3 set the exhaust valve down much more gently on the seat than another street performance cam I had measured at the same time. I expect it would be quite a bit quieter and easier on the valve train, something to consider for a daily driver. I have a few more cam measurement files saved off that you might find interesting. Drop me an email if you'd like a copy.
The XR264HR should make an awesome LTR TPI cam. I'd even be tempted to have a custom cam ground that combines the intake lobe of the XR264HR with the exhaust lobe of the XR270HR if running the stock 083 heads since the exhaust flow of these heads is so bad. You basically end up with a slightly hotter ZZ9 clone.
06-04-2005, 08:34 PM
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Car: 1989 IROC-Z
Engine: 5.7L EFI LTR setup
Transmission: T-5 World Class
thanx alot for this . I have been trying to find it for a bit now 
all I can add is I like this cam . from just off idle it really makes some power but leaves alot to be desired up top.
all I can add is I like this cam . from just off idle it really makes some power but leaves alot to be desired up top.
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