Yea!

 

I have a friend who has spent a lot of time and money on 3.0s and he says something funny. He says that with the 3.0, Toyota made a great 190hp engine and suddenly realised that it was all in the top end so they added a more restrive plenum smaller valves and lost a lot of that power to gain lower end power and torque.

We may not be able to properly fix all this. A better cam might fix that, I would be happy if the cams didn't really increase the power but drew out a nice flat powerband. I'm not giving up on the plenum though I'm gonna try and build one with longer runners, plenum and direct flow.

 

Agreed. Look at my dyno sheet, specifically the torque curve. Now where it starts to peak if that could just continue on for another 1-1.5K RPMS instead of falling off like Niagra Falls then it would be one powerful motor. I think cams are headed in the right direction, with cams you have the most influence over the torque curve, more specifically rasing the RPM of the power band.

 

Ehhhhh, I really don't believe that. Your runners, pleumn, tb, and everything else isn't any more restrictive than any other Toyota v6, or most of the i4's for that matter.
The SOHC is costing ya 10-15% VE across the board compaired to the DOHC heads, That's not really too bad. What is bad are the cams. Those bad boys are choking huge.

There are too many engines in that displacement, with 12v heads making way too much power, and way too broader power to blame it on the SOHC.




Blame the cams. Once you get past the cams, then ya, pretty much the same problem all the v6's have. Crappy post header merge pipes, pretty conservative tuning from Toyota, pleanty of room to port & polish, unshrould the valves & give it a bigtime valve-job.

 

Ill be taking care of the first 2 less then a mth away from that

 

so as a person (me) about to underatake a custom Y pipe build for my headers before i drop it off at the exauhst shop for the after cat part....

whats the diff between a crappy merge and a "good" one.

 

On the toyota cars, 10-15bhp.
On the VQ30de off a Maxima 15-20bhp.
On a 3.0L honda, 10-15bhp.

On the 2vz-fe (Same exhaust setup as yalls, turned 90*) 10-15bhp without doing headers. With... 15, maybe squeezing 20 at high stock rpms.

 

The dyno will tell all.

I know that the Downey extrude honed plenum dynoed at 8hp on a stock setup. I think with an extra 1/8 of diameter in the runners, longer runners and single directional flow plenum I can get more then that and increase the milage by reducing all the turbulance in the air flow.

Here's the simple version of how I see the plenum working as is.

1. Air comes in the 53mm TB at WOT. 53mm is small but maybe not too small for the 3.0, we do know that a 3 mm OB does have an effect at WOT probably because that increases the size to almost match the 59mm - (size of egr pipe) intake tube.

2. air travels down the ~57/58mm intake tube which isn't all that smooth but we'll say that thats OK for now.

3. Air hits the back of the wall of the chamber causing disruption and a posative pressure area in th center of the chamber which is smaller (I haven't measured yet but you can see by just looking at it)then the combined dia of the intake runners forget their volume.

4. Air moves from the smaller chamber where it is turbulant and enters the 35mm runners which are larger then the chamber meaning that already turbulant air looses velocity and thus momentum increasing the turbulance and further decreasing the momentum needed to make lower end power. Keep in mind that the rough cast sides of the runners are now adding to the drag because the air is so turbulant, this effectively makes the runners more constrictive.

5. Air comes into the 38mm lower intake runners which are larger then the upper once again loosing velocity and thus momentum then it gets the fuel and...

6. Then the air hits the small ports and valves of the head (this is another discussion altogether though).

An ideal intake is supposed to get smaller from the begining of the runner to valve and this one is the opposite. Look at some pics it is completely different from the 3vzfe (TB size?) and very very different from the 5vzfe(TB size?) which I would say is a very good design for a truck. The 5vz has longer runners to create the momentum needed for lower end power and is all uniform directional flow. I would even bet that all those guys who are putting 5vzfe engines in things like MR2s would benefit from the 3vzfe style intake over the 5vzfe one.

I think Toyota just made some simple mistakes with the plenum design likely cause it was their first kick at the cat and they needed something that would work more then they needed something that would work well. In the end they offered the market an engine that has more power then the 22re and didn't make so much power that it called too much attention to itself as they drew off market share from the domestic companies.

For mine I plan of using an altogether larger TB, larger intake tube as close to 70mm as I can with a larger(not quite sure of exact size yet) plenum and larger(38mm) longer(by about 2"-3") runners.

Kinda like this:http: //i25.photobucket.com/albums/c56/suprathepeg/Plenumdrawing.jpg

 

This thread is awesome. I cant wait to check in on it as you progress. I personally feel that you are approaching it very well thought out. Many people bash teh 3.0 but she really is quite sturdy and as potential. Will she ever be a screamer with 300HP??? NO but she can perform better and this thread will prove just that.

I went no where near the level some people on YT go to on there Yotas but I surely gained an improvement in performance from my top end rebuild just last year.

Keep us posted and include a few pics as you go please. Awesome!

-=Morphine=-

 

Us Canadians are just plain crazy at times

 

Just a quick update, I Finally got the bearings this week. So here is an update. .30 pistons were needed to get the huge score out of #1 cyl, crank cleaned up and rods are fine. Right now the machinest is P&P the heads and installing the OS valves on the bottom end a preassemble to set the deck height to zero in relation to piston height at TDC. This will ensure that quench is maximized and for any rebuild is very important otherwise you will loose power if you go to a larger piston as Ted has so elequently stated previously.

 

And now for some progress. I picked up the engine from the machine shop today. Bottom end and heads are assembled so there will be minimal work needed to get it ready for install. So far I'm into it for quite a bit but I'm really looking forward to the final product with the cams and all. It seems to me that 190 - 200 hp is a reasonable number with exhaust, headwork and cams, we'll see.

I hope to be putting it together and painting it this weekend. If so I'll takesome pics and post em up.

 

ARe you going to get a pair of weasy2k's 260* cams for the 3vze? ~38hp and ~46tq gain over 100% stock 3vze!

 

Thats the plan. I'm gonna be testing them for him on a more modified engine. They will be after the exhaust. I'm looking for close to 20hp out of the cams based on his results on an unmodified engine.

Others have said they consistantly got between 180-190 hp with the mods I currently have done to this engine without the cams so I think 190-200 is a reasonable goal.

 

this project is awesome

 

Did anything come of this? Are there any pics or anything to show for it? Or did it just die?

 

what happened here...

 

Cool project supra! Keep me in the loop please when I get some green I'll be wanting to do some of these mods meself. aviator

 

Are there any parts (EG from the 5vzfe 3.4 V6) that would work with the 3.0 that might increase performance?

 

THe cam portion is good...the cams have been in the 4runner for some time now and its more enjoyable to drive.

You cant put 5vz stuff into the 3vz-e