1UZ vs. 3UZ Heads (Worked ie: Ported)

[rocked]

In a word, the porting numbers @ .350 are absolutly horrible on a 1UZ, are the 3uz any better?! I mean yes, In a forced induction your forcing the air through and even the most horrible heads can flow, but. I see the restriction causing huge back pressure, now maybe this is because there isn't an oversize valve/more agressive cam profile, however, the stock lift, and stock head flow numbers, are absolutly awful.

Anyone have a billett head, or know of any other heads we can retrofit, because coming from the 2j, that head design being a G design was bad enough. The F design of theese motors, what the hell is going on here, the 1U is a bad ass little motor, but the heads, my god are they awful. Anyone know what guys are doing over 1400+ hp? If we could only retrofit a set of ford mod heads to theese motors then we'd be set, but 124cfm at .300 is a joke!

What are the top drag guys doing, billett heads? F that, there's no need to cutt out the cooling, what about welding up the heads and recutting? Is there anything we can do to get the head flow up around 250-300cfm without praying to a higher power or spending a massive amount of money reengineering?

I mean it's all relative, I can just pump more boost into the motor, but the beauty of bigger displacement is...so we dont have to do that to make power, but now I'm seeing the bottleneck here is the heads, the bottom end I know will hold 2000...top end on the other hand is a major restriction.

So what do we have?

 

[Anaema]

apparently the 2UZ heads are much better, a port and polish coupled with oversized valves, an aggressive cam profile, and maybe even extrude hone would get those heads flowing like Niagra Falls.

 

[rocked]

really....any numbers? 1u bottom with 2u heads..hrmm, well question, why do the racers run the 1u heads??? Just curious, must be some advantage..

 

[cowboy bebop]

Because until now, there were no proven 2uz aftermarket cam profiles on the market. : )

Eric

 

[rocked]

do you have any flow numbers off the 2u heads vs the 1u/3u bebop?

 

[cowboy bebop]

Just back to back pics. When you see the heads in person, side by side, the differences are even mroe apparent.

As you can see, especially with the 2uz, there's a lot of room for port matching.

Eric

 

[jibby]

That definetely looks like a better flowing head to me...Do these newer heads bolt directly onto the 1UZ block with no problems or alterations needed? Anyone know the comparable numbers like rock said?

 

[chrisman]

huge flow numbers dont necessarily mean big power--i think toyota knew what it was doing .. remember that these were only intended for everyday driving..
a 1200 hp toyota 2jzgte head when ported, flows about 220 at .3 lift.. then again,, that is a FI application.. remember that the larger the ports, the less street friendly the cars are..
huge ports are for race cars, and usually only good for upper end power..
but in a fi setup, you can do plenty with smaller ports..
the later heads-98 and up do flow much better out of the box.. so for better ultimate power, start with the later heads..

 

[rocked]

Eric, I'm talking about the 98+ 1U Heads, the pre-vvti are garbage heads it appears... World of difference in the pre 98 heads to the post...the post 98 heads look bad ass to say the least..

 

[cowboy bebop]

98+ 1uz heads have the same basic port shape as the 2uz heads, but I'm curious why you'd want to go with those heads since the aftermarket cam selection is zero due to the VVt-I.

I think Chris has a point there, also. The apparent improved flow of the 2uz heads over the early 1uz heads will only be effective on a more serious forced induction motor. If the car is going to be a basic daily driver that may have only 40 HP over stock, then more flow is not advised. In fact, as Chris pointed out, it may hurt performance. However, if you're going for the power, and want to move some air, the 2uz heads and cams seem to be the way to go.

Thanks guys,

 

[jibby]

Wait, so what you guys are saying is the pre 98 Iuz.. heads are garbage and the 98+ and up heads with the VVT-I flow much better? Can someone explain to me how that swap would benefit the older Iuz.. just better flow? Does the newer heads coming with from the VVt-i motor make the swap difficult.. I do appologise for all the questions but you guys have raised my curiousity about this head upgrade.. I have read up on the 3 angle valves, ported heads, etc.. just never considered the stock swap from the newer engines...Is the swap worth the trouble?

 

[cjsupra90]

no need to flow more the 124cfm (per cylinder) unless you plan on making more then 600 flywheel HP. Typically it takes roughly about 1.5 to 1.6 cfm to to produce 1hp, so if each port could flow 124cfm, that that would give you 992 cfm total engine flow. with that said, 992/1.5 = 661 HP and 992/1.6 = 620HP again, these are rough flywheel numbers. obviously these are not exact as barometric pressure, temperature, humidity, ect. are going to effect this but it does give you pretty good idea.

As stated and or implied by Chris and Eric, to large of ports to get big flow numbers end up killing port airflow velocity and therefor causes major lowspeed and off boost (FI applications) drivability issues

 

[qca]

Wait, so what you guys are saying is the pre 98 Iuz.. heads are garbage and the 98+ and up heads with the VVT-I flow much better? Can someone explain to me how that swap would benefit the older Iuz.. just better flow? Does the newer heads coming with from the VVt-i motor make the swap difficult.. I do appologise for all the questions but you guys have raised my curiousity about this head upgrade.. I have read up on the 3 angle valves, ported heads, etc.. just never considered the stock swap from the newer engines...Is the swap worth the trouble?

garbage ??
never ! the early heads work very well i havent heard one complaint yet :bigeyes:
the later 2 uz and 1 / 3 uz vvt heads are more efficient
i will throw a vvti 1uz and std 1uz on the flow bench and give comparisions
sorry i don't have a 2 uz head at this stage to put side by side as a true comparision on the same flow bench on the same day.
can someone lend me one ???

 

[Zuffen]

Flow isn't the be all and end all.

Gas velocity has a significant effect on power and drivability.

If you want a showpony that puts out 1,000hp but only at 8,500 rpm and has no powewr below 6,000rpm chase port size for high gas flow rate.

For a drivable and fa aster point to point car, gas velocity will give you less ourtright power but a faster car.

If all we care about is 1/4mile times go the big ports and have your car cough and splutter in the traffic.

 

[cowboy bebop]

Right, but that's an extreme Zuffen. The mroe efficient ports of the 2uz head woun't automatically yeild you a show pony with a 2000rpm powerband. Far from it. There's a lot of involved than that.

All I know is where you finish depends greatly on where start. Many on the board just want a basically stock 500rwhp car, and in that case, the stock 1uz heads fit the bill. But for those of us who run at least 800rwhp daily, there's got to be something more. I firmly believe the port design on the 2uz heads is the way to go if going after a truely fast car.

Thanks man,

 

[Lextreme II]

Many on the board just want a basically stock 500rwhp car, and in that case, the stock 1uz heads fit the bill. But for those of us who run at least 800rwhp daily, there's got to be something more.
Thanks man,

Honestly, I will be very happy with 500 rwhp daily driver. Why would i want 800 rwhp daily driver for? Its loud, rough idle and just plain bad street manner. I think 99% of this board will be very happy with 500 rwhp daily. Only someone is extremely into performance want 800 or 1000. Last few threads we talked about the complexity of swapping heads and other factors. Is it possible? Yes of course, but at what cost?

 

[cowboy bebop]

I don't know man, 500rwhp gets slow very fast. I know a few people with 650rwhp that can't believe how old it's gotten. One thing about the HP bug is that it keeps on biting, and demands more every time. I have a strong suspicion that when the Supra crowd gets a hold of this, they're not going to accept a cut in HP due to bad heads. We're pretty spoiled in the a lot of us run around town with 1000HP machines.

I've seen a few times where it's been theorized that the swap is complicated, but nothing ever shown. What is the basis of the difficulites, in your opinion? My 1uz is already at the machine shop with 2uz heads attached, all that would be needed a clean set of coil packs, an ECU, and a harness. All of which can be had for around $500.00. Is there somthing I'm missing?

Thanks man,

 

[jibby]

I have never heard or seen a car on the city streets sporting over 700 hp in my life, Ever.... Like I said a long time ago in a previous post, I can't imagine what a 1000hp car would feel like.. I would have to say a car with that much juice would be "the unbeatable car", Eric (Cowboy):notworthy

Also, I think we are all hp junkies on this forum.... Let's see now there is AA, GA, SA, etc.. maybe the National board of Rehabilition should consider HPA...no?
Hello everyone, my name is Jibby and I am an Horse Power Junky, "Hello Jibby......

 

[cowboy bebop]

Yeah, there's plenty of 2jz's running around with over 700hp on the streets of America. Plenty here in Orlando, that's for sure. : ) Plenty that drive their cars everyday, and plenty that are civil on the streets.

Thanks man,

 

[cjsupra90]

Yeah like Eric said, plenty of 2JZ's making that all over the place and then some.

Eric, yeah I agree with you on the fact that 2UZ heads should not hurt the drivability and should net a decent increase in flow.

I'd still like to see the flow bench numbers for all of the stock heads (non vvt-i 1UZ, vvt-i 1UZ, 2UZ and 3UZ).

Wait, arent the vvt-i heads the same for the 1UZ and 3UZ?