Tater13150

I have 1990 l98 with headers, the motor is completely torn down due to head gasket.. SO my question is..what kinda power would i gain by puttin a zz4 cam and springs in?! Also gonna port some of the intake and heads. After the porting and cam is the computer gonna be all out off wack!?

hotrod85z

iTrader: (1)

if your running the factory 90 model TPI, you'll definantely need a chip to get the MAP sensor to behave. other than that it should run very well! post your results! I am running a zz4 with camel humps in my 85 iroc-Z. it runs awesome even without a chip!

Tater13150

ttt

ULTM8Z

Here are the specs between the two cams:

IROC:

202°/206° Duration @.050
.403/.415 valve lift
115° lobe separation angle

ZZ4:

208°/221° Duration @.050
.474/.510 valve lift
112° lobe separation angle


That's a pretty good jump in all three categories. My experience with that ZZ4 cam is that its specs underestimate its performance. It definitely performs better than it looks on paper. I'd say you'd pick up at least 20 hp. If you had good cylinder heads and a manifold, it would be quite a bit more.

grumpyvette

the ZZ4,ZZ3 and chevys HOTCAM cams flat out suck ,IF MAX hp/tq is your goal, heres a crower 00471, in a ZZ4 350-with a restricted exhaust and shorty headers, (its obvious that the exhaust was hurting high rpm power , but look what the cam does at the lower rpm range)


http://www.crower.com/misc/cam_spec/...00471&x=12&y=4

BTW that zz4 350 made 361 rear wheel horspower and 532ft lbs of torque
these results came from CARLOS in GERMANY who was installing a zz engine in his cobra replica in germany, and asked for my advice as to a good cam to build more tq, without getting into detonation with the engines 11:1 cpr

heres what he wrote after the installation

yoooooohaaaaaa !
I installed my engine today, got the CROWER 00471 cam installed with 6° retard. After adjusting my Webbers the idle is quite smooth, idling at 600-700 RPMs. Engine feels like it would be a new one, runs extremely soft when cruising.
But boy... if you hit the pedal the Webbers start screaming like hell.
Ok folks, two days ago it was dyno time....

here you can see torque and hp of three stages of modification. peak dates first, tables & images follow later
the curve of the crower is FANTASTIC !!!

1. ZZ3 stock engine, no mods except my Webber 48 IDF carbs
2. same as 1, but heads ported plus TRW pistons added CR 11:1
3. same as two, but CROWER CAM 471 LM added, plus block hugger headers 1 1/2 replaced by 1 5/8 and tubing from collector to H-pipe increased from 2" to 2 1/2"

comments appreciated


1. 316 lbs ft @ 1.500 RPM, 319 hp @ 4.875 RPM
2. 425 lbs ft @ 1.875 RPM, 338 hp @ 5.500 RPM
3. 532 lbs ft @ 2.375 RPM, 361 hp @ 5.500 RPM

We had a very hard to hear detonation between 3.000 and 4.200 RPM but we immediately got rid of it by changing spark plugs from NGK BCPR6EY11 to Bosch Platin W4. Obviously the 6 type NGK became far too hot.

here are the interesting sheets

Power curves comparison

torque comparison curves

If I would have known how fantastic the torque curve looks like, I would have gone to a lower stall RPM. Maybe during winter time.

Grumpy ! Thanks again for the fantastic recommendation on the CROWER. :grin:

bigals87z28

yea, but for the cost you cant beat this cam. Its not for monster power strip hauler, but it is a very decent cam for a street car. Ive heard the ZZ4 engine plenty of times, and it is a very happy cam I cant wait to get it in the 305 with heads and some intake work.

ULTM8Z

Sucks? HA! Are you kidding me? You're comparing a 236° (@.050) cam against the ZZ4 cam? That's not even a fair comparison. OF COURSE that Crower will make more power. Look at it's specs. Albeit, it probably idled like garbage too. BTW, I have to ask where that dyno sheet came from.

I ran that ZZ4 cam for three years and it was a fantastic cam. It's great for someone looking for a smooth idle, good gas mileage but still wants torque all over the place.

Tater13150

I'm pretty much looking for a cam that works well with the stock tpi...(well ported) but stock none the less, Not worried about emissions as i am in indiana, main factor is the computer, i need it to work well with the stock computer, and from what i've been hearin the zz4 cam makes great torque and does well with stock prom.

ULTM8Z

That's correct. And that's the beauty of it, it will work well with a stock TPI system. My out of the box ZZ4 required very little modification to a 1990 Z28 calibration- albeit mostly in the ignition timing area. If you don't want to go the custom-PROM route, you'd probably be able to get away with simply advancing the TPS a little (maybe to .8V), increasing the fuel pressure a couple of PSI, and maybe a couple more degrees of ignition advance.

Irocster

If I install the ZZ4 in my new ZZ4 shortblock (in the near future), I understand that it will work O.K. with my stock computer, but what about emissions? I do live in CA and I do know that this cam and shortblock are illegal, but as long as I pass the sniffer I will be ok since there is no way they will know what I've got inside right? On a second thought, if they hear the rough choppy idle that this cam will probably produce over the stock L98 cam, will they question me of what is in it? Thanks.

ULTM8Z

Well, first of all, if they check the number on the block you're hosed anyway, because it says ZZ4 on it. But if you sneak past that gauntlet, without tuning, it may idle slightly rougher than stock, which means you're hosed again.

However, before my idle misfire, I had that thing idling like a stocker with some tuning- so it is possible. However, I'm sure it will pass the sniffer without any tuning- assuming the rest of your emissions system is in good order.