For some stupid reason I thought the ZZ4 had 1.6 roller rockers... Now I've done the job of course I realise they are 1.5 Stupid oversight. Do you think my HP will be about 380bhp (up from the 355?) They claim 394bhp with the 1.6 rollers and afer searching the site 9 million times can't get a definite answer.

Would it be worth me getting the 1.6's? Is it an easy job?

Many thanks,
Felix

 

Buying 1.6 Rollers are a good buy for quick increase of power. But I think with the swap you could get about 380hp out of it. The cam that comes in it is pretty potent so I think there would be a noticable difference with the swap.

 

Dyno it before and after the roller change to see results and wether they were worth it.

 

And is it a pretty straightfoward job? An afternoons work?

It does feel significantly quicker, just noticed that the ZZ4 cam has a higher exhuast lift though so wondered.

 

Sorry to come back to this again. So with an increased inlet valve lift (.494 from .476 I think) and a greater duration I should net more power? Thing is I have lost exhaust lift in the change from .510 to .494

It feels stronger for sure- just a bit paranoid...

 

How did you lose llift when you switched to 1.6 on the exhaust? All the rocker does is act as a mulitplier for lift (aside from the obvious job). The cam lift or lobe lift is a constant as it's ground into the cam. the rocker then mulitplies that lift by 1.5 or 1.6 depending on the ratio used.

rocker ratio does not physically change the duration as that too is ground in to the cam. It does alter the .050" in a sense i believe. It changed the duration without physically changing it.

The power increase is more from the lift, not the duration.

 

I didn't change to 1.6's. The change in lift was just from changing from a ZZ4 to a LT4 HOT cam. I ran/run both cams with 1.5 rockers.

ZZ4 with 1.5 rr's

In .476
Ex .510

LT4 HOT cam with 1.5 rr's

In .494
Ex .494

Not sure if the figs are 100% but near enough.

Cheers
Felix

 

Now I'm confused (well, not really). This whole thread is on 1.6 versus 1.5 rockers witht he ZZ4 cam. Then you post seemingly random figures with no ado to the HOT cam.

Just a thought, next time you talk about rocker arms, then turn around and swap cams, but make reference to ONLY the lift, be so kind and mention you swapped cams.

yes, the HOT cam is a more aggressive cam than the ZZ4. Should have done a before and after dyno. I'd like to see those numbers.

 

Sorry to confuse you, but the title of the thread is

"Need opinions on power of my ZZ4 with HOT cam and 1.5 rr's"

Not sure why I confused you so much? I think you read ZZ4 as the cam and not the engine?

Anyway thanks.

 

HAHA whoops. Yea, thats what i did. I saw ZZ4 and 1.6 so i assumed the cam.

Thats what i get for pulling an all-nighter.

 

No probs. So can anyone give me an idea?

 

That was the original answer, what do you want guesses.

 

The chances of me ever getting to a dyno are going to be nearly impossible. Plus what am I supposed to do take the cam out so I can get the 'before' numbers I mean come on!

Profound estimates would be nice.

 

I'd say swapping from the ZZ4 CAM to the HOT CAM you gained an honest 30hp. And I bet if you run a 1.6 ratio Roller Rockers with the hot cam youd be about dead on at the fly wheel with 400hp.

 

Typically on a motor like yours, switching from a 1.5:1 rocker to a 1.6:1 rocker will add a little HP to the top end above 3000rpm usually about 4 to 8 hp. Simular to installing a slightly larger cam would have on the overall power band.
It also chops a little off the low end, typically a few ft/lbs.
Your heads, in unported form will respond minimually from minor lift changes beyond about .480"+/-.
Changing the cam grind altogether will have a much more profound effect.
Don't expect big things from a rocker ratio change.
Why not take it to the local track and see what she's got now and go from there.
A set of ET street slicks and some 4.10's will give you a lot more bang for the buck. That 'ill set yu in your seat!!!

 

Thanks guys, just what I wanted.

 

Problem there is Felix is an inconsistent driver at the best of times.

 

Rob you dawg! Let's take it to the track