dirtwarrior17
Banned
It sounds like some afrs would solve that problem like mentioned before... i plan to get those 74cc afrs for my 10:1 355 (with 64cc heads) so i can get away with 89 octane. Not to mention the hp and tq boost.
CK5
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ZZ4, anybody running one?
- Thread starter k5james
- Start date
k5james said:
In a pinch....I've had to put 89 in mine...
(there's NO high-octane near my trails)
It ran...just not as well.
In my zz4 manual...91 or higher is recommended.
I run 94 Ultra...because it runs best on that gas.
k5james
1/2 ton status
Ok, that's not too bad then, like I said, I'll try it as is and then if I don't like it I'll try and swing some AFR's.
Isn't it an aluminum fastburn chamber head on the ZZ4?
If so, it should respond just like a Vortec head...less timing needed at high RPM's, more timing good down low.
I find it hard to believe that a 10:1 engine, fast burn/AL head can't be run on 91 octane.
You can run up near 9.5:1 with Vortecs (which are cast iron of course) on 87 octane, I don't see why you can't run 10:1 on 91 octane with a similar head in AL and extract all the performance possible from the combo.
Just my thoughts anyway, max possible timing doesn't=best performance.
If so, it should respond just like a Vortec head...less timing needed at high RPM's, more timing good down low.
I find it hard to believe that a 10:1 engine, fast burn/AL head can't be run on 91 octane.
You can run up near 9.5:1 with Vortecs (which are cast iron of course) on 87 octane, I don't see why you can't run 10:1 on 91 octane with a similar head in AL and extract all the performance possible from the combo.
Just my thoughts anyway, max possible timing doesn't=best performance.
k5james
1/2 ton status
Well, the deal on the zz4 fell through. I'm talking to a guy on another board I frequent about a custom zz4 longblock that is basically everything that the zz4 comes with but using the 68cc, 195cc AFR heads instead. I'll only have to pay the difference in price on heads. What kind of power do you think I'd be getting out of that puppy?
beastofablaze
1/2 ton status
Just a guess but i would say 410 hp and 435 ft lbs of tq.
JIM88K5
1/2 ton status
Well, GM's Fast Burn 385 is a ZZ4 with the fast burn aluminum heads. It make 385 ponies, same short block, same camshaft... The GM Performance catalog says these are 500 horse heads out of the box... They are a 25 horse increase on a ZZ4. I would bet that any other performance aliminum head would make a similar increase in power. I think 380-390 horse. When you put bigger heads on it your gonna put your power band at an unusable level. I thought you wanted a 383 ?
k5james
1/2 ton status
JIM88K5 said:
I do want a 383 but you can't beat the price on the zz383 and I can't get a straight answer on if I'll be able to run it on 87 octane every once in a while or not.
dirtwarrior17
Banned
that thing has 10:1 right? If it does you won't be able to get away with 87 unless your idleing down the road. Actually you can do it but it will ping like a muther f*cker on 87.
k5james
1/2 ton status
Actually, the zz383 is like 9.7 or 9.6 to 1. I read on another forum that up to 9.8 to 1 is doable with aluminum heads. 
Octane vs. compression etc.
Down at the bottom in yellow is what I was thinking of. Fast burn heads in aluminum with good timing and fueling should be pretty close to tolerant of 87 octane at 10:1. I think GM's the only one making aluminum heads with the good combustion chambers though. Yet another reason why flow isn't the only thing that makes heads good or bad.
GM's reasoning for saying 91 octane is to probably keep people safe. I imagine there is a warranty, but even if there isn't, it wouldn't be hard for people to take a 10:1 engine apart by just advancing timing as far as possible, then running it on 87. Then GM would have to deal with their complaints.
Down at the bottom in yellow is what I was thinking of. Fast burn heads in aluminum with good timing and fueling should be pretty close to tolerant of 87 octane at 10:1. I think GM's the only one making aluminum heads with the good combustion chambers though. Yet another reason why flow isn't the only thing that makes heads good or bad.
GM's reasoning for saying 91 octane is to probably keep people safe. I imagine there is a warranty, but even if there isn't, it wouldn't be hard for people to take a 10:1 engine apart by just advancing timing as far as possible, then running it on 87. Then GM would have to deal with their complaints.
beater_k20
Banned
actually, its pretty easy to beat the ZZ383's price. you could build 2 engines that would fit your application better for the $4500+ they're asking for it.
9:1 383, Vortec heads, and an XE 262 cam should run just fine on 87. according to DD2K, peak horsepower is 342 @ 5000, peak torque is 430 @ 2500, with a pretty flat torque curve all the way to peak hp. a little blueprinting, and i wouldnt doubt you could squeak 400hp out of it. the XE 262 is tame enough that you just may be able to get away with a factory style TBI setup with some mods to it.
9:1 383, Vortec heads, and an XE 262 cam should run just fine on 87. according to DD2K, peak horsepower is 342 @ 5000, peak torque is 430 @ 2500, with a pretty flat torque curve all the way to peak hp. a little blueprinting, and i wouldnt doubt you could squeak 400hp out of it. the XE 262 is tame enough that you just may be able to get away with a factory style TBI setup with some mods to it.
beater_k20
Banned
k5james said:Actually, the zz383 is like 9.7 or 9.6 to 1. I read on another forum that up to 9.8 to 1 is doable with aluminum heads.
the ZZ383 is 9.7:1
you can go much higher than that, but you must cam accordingly. i just ran a 10.7:1 350 through my dynamic compression ratio calculator. with an XR294 cam in it, a set of Vortec (or better) heads (advanced combustion chamber design, and cautious tuning of the ignition timing, you should be able to run 87 octane without too many problems. you could probably push 11:1 with a set of aluminum heads.
dirtwarrior17
Banned
I thought he was getting a zz4? I don't know about the zz383 but the zz4 has aluminum 58cc vortecs and i think the 383 does too. In that case(thought they were iron) 87 is very doable considering you can carry your timing gun with you.
beater_k20
Banned
dirtwarrior17 said:
ZZ4 uses L98 Vette heads (58cc chambers), the ZZ383 uses GMPP Fastburn heads (62cc chambers)
there is no aluminum Vortec head that will fit a Gen I smallblock.
beater_k20 said:
I'm not quite sure what the difference is between the fastburn AL head and the Vortecs short of material. They have raised runners and fast burn chambers, both Vortec attributes, and appear from GM's pics to have both the Vortec intake bolt pattern and the earlier intake pattern as well.
I guess the 2CC difference is about the only "big" difference between the two?
beater_k20
Banned
dyeager535 said:
GM Perfomance Parts engines are not Vortec engines. plain and simple, Vortec engines are factory installed. go to your local GM Parts counter, and ask for Aluminum Vortec heads. my guess is the guy will look at you like you're retarded. if raised runners and a combustion chamber make them Vortec heads, i guess the 882 heads i have in the garage must be camel humps. after all, they both carry 30+ year old technology and have the same bolt pattern.
JIM88K5
1/2 ton status
I'm sure you can run the crap gas, just back the timing off and be cool with it...k5james said:
beater_k20 said:
So somewhere I said that fastburns are vortecs? They share attributes, and they are related designs. There are obvious differences, doesn't mean they can't be compared. As they apply to performance, it appears the differences are slight.
beater_k20
Banned
180cc or smaller runners vs 200+cc runners... that's a pretty big difference. nothing slight about that.
