ports? - Toyota Nation Forum : Toyota Car and Truck Forums

fredk · 01-19-2005, 09:27 PM

Well, I think I have found an oddball head or there are 2 versions of the gen1 ge head for the s block. OK the heads are identical in every way except the intake ports. They both came off a 3sge with the tvis and no turbo, anyways, the intake ports are the same at the gasket face, HUGE, then one head, the sides come in twards the center about half way in, about in line with the valve guides, then the widen back out to go twards the valves, and the canal where the fuel shoots out of the injector fans out, and the other head, the sides are straight all the way in and the injector fueling area is just a ditch, Is one head better than the other for a turbo or building an n/a motor?

alltrac165 · 01-19-2005, 11:35 PM

Yeah, I got one of the oddball ones where the port stays huge all the way down too. I'm told it's off an early 3sge. The head on my 3sgte is the kind where it necks down then opens up to the valve. Beats me which is better...

Pineapple · 01-20-2005, 10:32 AM

The TVIS head is called "big port" I believe. TVIS is there to improve lowend torque. Later gen GE engine use "small port" cause they can design better head and port to remove TVIS. The late gen small port is better cause it flows better. As long as you can bolt it on to your block.

Corolla and 4A-GE guys will know more about that.

Kwanza · 01-20-2005, 11:55 AM

Quote:

Originally Posted by Pineapple

The TVIS head is called "small port" I believe. TVIS is there to improve lowend torque. Later gen GE engine use "big port" cause they can design better head and port to remove TVIS. The late gen big port is better cause it flows better. As long as you can bolt it on to your block.

Corolla and 4A-GE guys will know more about that.

Correct... but you got it backwards. "bigport" is TVIS, "smallport" is not... ;]

Pineapple · 01-20-2005, 12:09 PM

Ok, looks better now?

Toysrme · 01-20-2005, 02:51 PM

I can't help you, but I can help you.
(assuming the porting is on a fairly even level)
Larger ports always have the ability to flow more air. Larger pipe... More stuff can fit through it.
There is an exception.
Smaller ports will have a higher velocity to achive the same airflow.

If the cams are setup in a typical way of pulling most of it's air in during the beginning through the middle of the time span the valve is open, the incomming airflow will taper off during the end of the valve cycle.
However, if the cams are setup so that they will achive very high velocity through the middle, and end of the cycle; there will be more power found from the smaller ports.

Now you just have to sit and compair cam durations vs power made vs what previous people have done

. I think I just confused, or complicated the matter.

With the turbo, I would pick the larger ports heh.

automatic · 01-20-2005, 05:54 PM

I'd be tempted to use the large port head even on an N/A motor if the intake runners(manifold) were sized well to help with the velocity.
I'm always in favor of the straightest intake port, since many cars stray far from this basic principle.
Sounds like the other head was done to create swirl, maybe for emissions reasons?

Pineapple · 01-20-2005, 06:05 PM

The TVIS, small port was done due to leck of technology to design and make a better flowing head. It was the solution at that time.
Now with better computer and manufacturing method, they can produce a better flow head without TVIS.
TVIS has 2 runners at each intake port. One is close at low rpm to improve velocity. Port open at around 4000rpm to help flow at high rpm.

fredk · 01-20-2005, 06:10 PM

I did notice that down in the spark plug valley there is a 3 on one of them and a 1 on the other, now I also have another entire 3sge with tvis and there is no numbers on it but i dont know whitch head is on it since the motor is all together, One reminder in this, the smalliish ported head came off an 88 with tvis