Twin Turbo/ZZ4 question

[Ummgawa]

I was reading on Bank's site that at 6lbs of boost, a ZZ4 krate motor was an ideal candidate for the twin set up. That particular engine, based on my investigation, has Hyperutectic pistons, pinks (or equivalent) steel crank and stock balancer. Am I missing something here? 12 lbs boost requires Forged, billet Yadda Yadda. but 6 requires minimal metals IYKWIM.

Now I understand the concept on Boost and increased cylender pressure, etc and the need for the hi dollar stuff for the 12 lbs. But the 6 lbs? surprises me that one would suggest the lesser set up at all. Seems to me the engine would be mincemeat if you really drilled the motor for any length of time or even all at once. any thoughts?

[camcojb]

Originally Posted by Ummgawa

I was reading on Bank's site that at 6lbs of boost, a ZZ4 krate motor was an ideal candidate for the twin set up. That particular engine, based on my investigation, has Hyperutectic pistons, pinks (or equivalent) steel crank and stock balancer. Am I missing something here? 12 lbs boost requires Forged, billet Yadda Yadda. but 6 requires minimal metals IYKWIM.

Now I understand the concept on Boost and increased cylender pressure, etc and the need for the hi dollar stuff for the 12 lbs. But the 6 lbs? surprises me that one would suggest the lesser set up at all. Seems to me the engine would be mincemeat if you really drilled the motor for any length of time or even all at once. any thoughts?

I would say at that boost level it's all in the tune. If it doesn't detonate it should lead a long and happy life. If it does it has no extra protection that a forged system would have (you never want detonation in any motor, especially forced induction) but you get the point.

Jody

[Ummgawa]

Thanks Jody for the quick answer. Bummer about the paint. Any hopes of makin the tour?

[camcojb]

Originally Posted by Ummgawa

Thanks Jody for the quick answer. Bummer about the paint. Any hopes of makin the tour?

Not in my car! But I'll still be going.

Jody

[hotwheels]

you are right on your thinking, but 6lbs of is pretty safe on pump gas, and actually you can run 8lbs safely. You just need to back off your timing a bit if you hear some pinging........10lbs and over, you should go all forged, which will ensure the motor is strong enough to handle the added pressures..........later, hotwheels

[Steve Chryssos]

Yeah. I'm with Hot Wheels. I've seen pix of your project Jim. The car is way to cool for a ZZ4--even a ZZ4 with a turbo. In this day and age, there are numerous engine builders who have standardized engine packages with quality parts. Call them crate engines if you will, but these standardized packages save you money because the engine builder bought the key components in quantity (as opposed to one off custom engine builds)

[Ummgawa]

Steve, I was asking a general question. I have reworked the 406 with the W/C top end and I am still going to use it. Just had to get some serious pistons made by JE with a different rod set up. Ouch. I know it will be worth it, though. I just had not planned in advance to do the twins. Not till I met up with you dudes that is.


Course my engine builder is as happy as a fat woman at a Gravy tasteing contest.

[BigAl...]

I'll try and shed some light on this issue. There is no black and white cutoff point, you could easily, I repeat EASILY run 15 maybe even 20 psi of boost on stock parts BBUUTT (like mentioned earlier by Jody) the tune must be on the money!!! Let's use a specific scenerio, I'm guessing the CR of the ZZ4 is around 9:1(?) on a well matched turbo system with a good intercooler (big help in controlling deto.) you could easily run 12-15psi of boost assuming you had a wide band 02 setup to keep an eye on the afr's (make sure they stay at a friendly 11.0-11.5) and run reasonbly low timing and 93 octane gas and "you should lead a long and happy life". Now with that said, if you run 87 octane or try to bump up the timing thennnnnnn, NO MORE LONG AND HAPPY LIFE!!! obviously if I'm wrong about the CR being 9:1 and the ZZ4 is say 10 or 10.5:1 the tune may need to be a little richer or maybe 1 or 2 degs less timing. Guys the parts don't let you run more boost/power they just try to save your ass when you get to agressive with the tune! forged pistons, billet crank/rods just make the margin for error a little wider but are still no match for some healthy detonation!

please guys no flames, this has been my experience!

BigAl...

[Ummgawa]

This why this is the best damn PT site on the net. Period. There are plenty with more members, but, this site is it. Thanks.

[Steve Chryssos]

BigAl,
No flame here. Just hate to see a car of that caliber run a generic engine.
Jim,
Glad to hear about the 406. And the fat lady will have to get in line. If there's one thing I love, it's gravy!