TPIS's published specs on their ZZ9 cam:

Duration (@ 50): 212/226
Lift (1.5 rockers): 0.483/0.520
LSA: 112

IVO: 1.8 ATDC
IVC: 33.0 ABDC
EVO: 49.2 BBDC
EVC: 3.8 BTDC

I was forwarded a document recently from someone who bought the ZZ9 who checked its specs on a Cam Doctor. The results are far different from the published values. They are:

Duration (@ 50): 208.2/223.5
Lift (1.5 rockers): 0.480/0.519
LSA: 111.9

IVO: 6.3 ATDC
IVC: 34.4 ABDC
EVO: 44.8 BBDC
EVC: 1.3 BTDC

Although the lift figures are within specs, the valve timing events are very different. Running both profiles through Desktop Dyno 2000, the "measured" cam produces far more power and torque than the "published" cam. I do know that TPIS's cams use asymmetrical lobe profiles, which no other cam manufacturer uses but I cannot see this fact changing the valve timing events, only LSA.

I can't help but wonder if TPIS knowingly publishes false information to keep the true ZZ9 specs a secret.

My suspicion is somewhat confirmed when you examine their Super Profile L98 cam. Tim Burgess is the only person I know of that runs this cam. With a duration @ 50 of 218/219 and lift of 0.415/0.433, this cam seems extremely tame. Yet Tim runs low 13's with it in his 305 (naturally aspirated) which seems utterly impossible.

Does TPIS knowingly give false information to the public so others cannot "copy" their ZZ9? Anyone have insight on this issue?

------------------
Willie

Supercharged 1987 305 IROC-Z, Daily-Driver, Emissions-Legal.
Former Paxton (6-psig) with 50-hp nitrous: 12.043 @ 112.86 mph.
ATI D1SC (10-psig): 12.056 @ 116.62 mph.
All stats are altitude corrected for 3,100 feet using NHRA's Altitude Correction Table.

http://willie.camaro-firebird.org/

1987 "20th Anniversary Commemorative Edition" Z28 Convertible -- Super Chevy Show Class Winner, 1998.

[This message has been edited by Willie (edited November 02, 2001).]

 

I'm not standing up for TPIS but to be absolutly fair I think that you would have to compare more than one zz-9 cam because it could just be a machining fluke you know. Thats why you r supposed to degree all camshafts, to make sure there wasnt a machining problemor that you were not sent the wrong cam. It happens!!

------------------
87 IROC-Z
305 AUTO 2.73 OPEN REAR, T-TOPS, GUTTED AIRBOX, HOME MADE RAM AIR, AIRFOIL, UNDERDRIVE PULLEYS, ACCEL CAP & ROTOR, ACCEL COIL, TPIS WIRES, BOSCH PLATINUM PLUGS, JUST HIT 80,000 MILES

 

Hey Willie...how are you.

If they were to keep their "receipe" secret...what would the benefits be...compared to the downfalls. If they intentionally publish less aggressive and powerful designs then perhaps an uninformed consumer would perhaps choose a different cam, right?

I can see what you mean though. And that type of thing does happen, at least I believe it does. Companies "masssge" numbers one way or the other all of the time. Sometimes it is very beneficial to post lower claims than are actually true. But I'm not sure on the cam specs though. I'd be interested to hear what you find out.

Oh yeah, when are you going to update your website?


------------------
http://www.gruveb.com/z28

 

I just might have to tell Myron about this.......

I'll keep ya posted if he has anything to say about it.......

------------------
1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

Willie....did you get my email about the pictures?

also on this issue:

it could be possible to lie about their cam specs...companies have been doing it for years

Some companies wont even GIVE YOU A CAM CARD

 

Hmmmm....this is very interesting. Keep us updated with any new information.

 

Well I did get a response from Myron. I cannot speak for him though, and he knows about this topic....

But I guess I can give some quick ideas that I have about his explanations for the findings.....

First off, there are very few people out there that know how to truly degree a cam correctly and it does not take much to skew the readings....

Another thing to think about is the actual grinding of the cam at the factory. The grinding stones will wear down during use and the actual diameter of them will change. This can have an effect on the profile of the cam but not the actual lift figures. TPIS suggests using the 'intake centerline method' of measuring the cam to find it's dimensions.

So I guess the differences are not intentional and definately not a 'sand bagging' technique....

------------------
1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

Let me make one point... food for thought if you will.

1)
TPIS publishes the intake valve opening as 49.2 degrees BBDC. The measured value is 44.8 degrees.

2)
The published exhaust valve opening is (-1.8) degrees BBDC. The measured value is (-6.3) degrees.

These discrepancies are far from being within any kind of production tolerance. They are grossly different.

Fact)
When "both" cams are plugged into Desktop Dyno, the measured cam produces more power and torque.

Opinion)
The fact above would make this cam seem more powerful than a cam with the same specs produced by another manufacturer. I believe TPIS does this on purpose to make their cam stand out among the rest. And by doing this, they can price them much higher than the competition (which they've done). Who else sells a hydraulic roller cam for an atrocious $375? No one. Again, just my opinion.

Willie

 

May be "someone" got the wrong cam
sounds like a late factory ZZ4 cam,
from the Cam Doctor numbers....

 

Maybe, TPIS just hasn't updated their website in a while and the specs have changed. Is this a brand new cam? or an older one? I'm pretty sure (don't quote me) the crane cams admits to continually modifying each specific cam grind to make it better, more powerful, so that you could have 2 cams with the same serial number but not the exact same grind. Does you friend with the ZZ9 cam have a cam card? That should match up with his experimental values. I doubt TPIS would really publish false numbers on purpose, that's bad business. Probably a simple phone call to TPIS would solve everything and answer your questions.

As for their super profile L98 cam, I thought TPIS explained their reasoning behind the low lift numbers and who knows how eccentric the lobes are on that cam.

It sounded like you, yourself posted why they charge an outragous price for their cams considering "TPIS's uses asymmetrical lobe profiles, which no other cam manufacturer uses".

I don't think I would ever buy anything from TPIS(unless money ain't a thang), but that's my thoughts about it.

------------------
14.62@96mph headers, muffler, chip, ghetto stuff, duct tape
89 GTA 305 TPI 5 speed 3.42 gears

 

Im interested in this.. anyone else have experience with this cam? Im running high 13s with an LT4 stock cam and 1.6rrs, what do you guys think? What kind of heads/intake is Tim using?