Stroking the 1UZFE and 8 throttle bodies

The 1UZFE EGR Delete Kit is available for sale here.
These are precisely what I will be using on my VH45 8-throttle conversion...

I already have 12 (two sets)... they're hard to get hold of, and no-one will sell them seperately... I'll sell my oether 4 later, or keep them for a 4 throt conversion on something else :)
No picture unfortunately.

But they are a diecast metal block 38mm thick, and each individual block has a pair of 45mm throttles on the same shaft, spaced 90mm apart. Each block has it's own return spring and throttle stop. There are four 8mm mounting bolt holes.

On the GTR there are three of these throttle blocks. Each block has a bellcrank on one end, and an adjustable length link to synchronise all three pairs of throttles.

On a V8, I guess there would need to be a main central throttle shaft running right down the centre of the motor from front to back. That would then have four bellcrank arms fitted to it, and four adjustable length links to operate the four pairs of throttle bodies.

Sorry for all the words, I have a complete GTR induction system right here beside the keyboard, but no camera unfortunately.

They do turn up from time to time secondhand. Some of the drag racers remove the individual throttles and fit a very large single throttle. It shortens the intake runners by about 40mm, they say it also increases full throttle airflow. Also, having only one throttle makes using a MAP sensor a lot less difficult with really hairy cams. So for serious drag racing the beautiful individual throttles sometimes get junked, believe it or not.
Thanks for the pics; I've always thought the ultimate in s*x appeal for a motor was a string of ITB's, or of course Webers with trumpets. Having owned 2 old E-types, I also remember what a PITA it is to synchronise multiple throats.

Yes individual trumpets do look and sound nice, but lack of an effective aircleaner can do terrible things to your cylinder bores and rings.

The GTR has a small secondary plenum after the throttles. This is a connecting passage that runs along over the top of the six intake runners. A metering hole connects this passage to each runner to equalize the idle vacuums. It compensates for slight errors in throttle plate angle, and makes it very easy to get a dead smooth idle.

Look in the second picture next to that pink wavy thing. The secondary plenum bolts on top, and sits up high. In the middle of this secondary plenum is a black barbed fitting sticking up at an angle, that connects this secondary plenum to the PCV valve in the cam cover.

Something like this could be duplicated in a V8 manifold easily enough. It takes all the pain out of synchronising the throttle plates. It is also a rather convenient place to reference your MAP sensor.
Toranajudd unless your 1UZ is going to rev hard to at least 8000rpm, the eight throttle bodies are going to look pretty yes, but it won't give you the big power numbers you seek. I know i guy who went backwards changing his single tb setup, he lost out big time. It made less torque and hp than it did before. Not a happy man i can tell you
Superlex1, there must have been some other tuning issues there. Simplistically, an engine is just a pump, and anything you can do to relieve restrictions on the inlet and outlet will improve its peak performance. As we all know, it's all about flowing as much air in as possible, and flowing as much exhaust out as possible. In between, of course, it doesn't hurt to have great combustion going on!

I would believe ITB's probably hurt the low end torque curve, if the old single TB was the OEM size, but hurting the top end is hard to believe unless there were other issues.

Bigger isn't always better, in some cases there is a limit. Sure a multi-throttle body intake can make more power up top than a single tb setup, but the engine needs to rev to take advantage of this extra air. Otherwise you are losing air speed by going too big. Eg the RB26 and 4AGE are both hi-revving engines
Individual throttles make no difference to torque or horsepower, all they do is give you a much crisper throttle response.

Think about it. When the throttle is wide open, it effectively almost totally dissapears from the flow picture. It could be located anywhere, and if it is held wide open it doesen't really matter where it is located.

Which is going to have less flow restriction, a completely empty runner, or a runner with a throttle shaft going through it ?

If you want big dyno numbers, use a single large throttle body. You can make it as big as you want. Individual throttles can be no larger than the induction tracts. But you could make a single throttle body twelve inches in diameter if you really wished.

But if you want to be able to snap the throttle open and hear the engine go from say 1,000 Rpm to 9,000+ Rpm and back to 1,000 Rpm in a fraction of a second, that is what individual throttles located very close to the intake valves can give you (along with minimal rotational inertia). That sound the formula one cars make when bliping the throttle in the pits is like nothing else.

A formula one car, especially in the wet would be undrivable with a single large throttle. Motorbikes would be a lot less fun too.

So if you expect that fitting multiple throttle bodies is going to increase power, think again.
I agree you do get better response with individual throttles. There is another variable which is very important to consider and thats the length of the trumpets (induction length) these little babies can make a lot of different in the way the engine produces its power and the ideal length is heavily influenced by the other components. There will always be a sacrifice to make either up top or down low in the rev range.

Getting back to ToranaJudd unless your building a full race engine and prepared the rev it hard, you would be better off going to supercharged or turbo route. Trust me and ask alot of guys here, you make more power, it will be more streetable on the road, more fun plus you will probalby save some cash in the long run
Spot on Superlex1, agree 100%.

Sure it is possible to tune a normally aspirated engine to give more power, but you will end up with something that is noisy, peaky, and will probably wear out a lot faster because you will have to rev it fairly hard to make it go. Fuel is not getting any cheaper either.

Supercharging or turbocharging will give far better results in every respect, especially for a reguistered road vehicle.
hmm. one thing that no said was the tuning. The ITB is a bit easer to tune but the magic is in the runners.
runners into a big pipe. Or ITB the length and size needs to be tuned. There is also a size the big pipe at the end need to be if there is one. if any of the parts are wrong and you will see big loss in power.
tuning of the headers is part of it too. The length and size to free air or the first chamber. a cat for most cars.
for example one of the alfa guys removed there cat and replaced it with a pipe thinking it would give them more power. but what happened is it detuned the headers and the car lost a lot of power.

I have seen this with a lot of ITB setup there are too fat and way too short. if you do the math they are tuned for 15000 to 20000 RPM you will need somthing a lot longer to get the tune down to where you want it.

anyone thinking of making there own intake or headers should get somthing like performancetrends Engine Analyzer and run the numbers. just hacking somthing together might look cool but it will run like crap.
The rod journal diameter of the 1UZ is 52mm. I would suggest using a stock crank with an offset grind down to a rod journal diameter of 42mm. It's very easy to find 45mm rods to use with that journal size (if you can't find them at the 1UZ width, .904", then you can always widen the journal a little). You'll also gain 10mm of stroke. Move the wrist pin up 5mm to compensate for the increased stroke. If you source a 2UZ crank and grind that, then you'll have even a bit more stroke.

97mm bore would definitely be possible, with sleeves. Typically, re-sleeving costs about $600 or so for 4 cylinders. You'd need to find a company who makes sleeves, I'd suggest as they can make a sleeve for just about anything. In fact, you could probably just buy some of their automotive sleeves, have them installed, and bore to your liking.
The individual throttles really help to tame a wild cam by eliminating the cross-pulsing in the plenum. This allows a race engine to be able and drive on the street(cool).
I have thought about trying someTBs from a bike, casting a manifold at a local foundry, but since I don't have wild cams,and won't be getting any, will have to wait on that one.
The sound of an individual runner intake can be very addicting.
The individual throttles really help to tame a wild cam by eliminating the cross-pulsing in the plenum. This allows a race engine to be able and drive on the street(cool).
I have thought about trying someTBs from a bike, casting a manifold at a local foundry, but since I don't have wild cams,and won't be getting any, will have to wait on that one.
The sound of an individual runner intake can be very addicting.
For mild cams, a plenum intake with tuned length runners as Sylalfa has mentioned, would be the ticket. The oem runner lengths,diameters are setup well for the existing cams,valve sizes,displacement, but would be the thing to change once the engine has been pumped up in size, with slightly bigger cams. Similar to this...
There has been a lot of success using bike ITB on the 4cyl cars.
it has been used a lot for cars that did not have injection before

That carbon fiber mannifold will also help keep the air cool as it will not trasfer heat from the heads
SCV8 is right about taming wild camshafts. To do this the throttle bodies must be located as close to the intake valves as possible. There will then be very little trapped volume between a closed throttle and the intake valve.

During MASSIVE valve overlap, exhaust is far less likely to be sucked back out of the comustion chamber by the high manifold vacuum genated at idle and small throttle openings. At least not back any further than where the throttle is located.

On the other hand, if you have a large volume plenum and a single throttle body, exhaust could be sucked almost up the whole induction runner length with the same MASSIVE valve overlap. The engine manners would be very bad, and when you pull the intake manifold off, you will most likely find black crap a very long way back up all the intake runners from severe exhaust reversion.

So if really wild camshafts are planned in a street engine, and you want a reasonable idle and decent low Rpm manners, bolt the throttle bodies right onto the cylinder head (if you can). It may still be totally gutless at low Rpm (with those crazy cams) but at least it will not be quite so lumpy and spit back at you quite so often.

Individual throttles will greatly enhance drivability and throttle response. They will add nothing to power output.
I once sent my mom to do some errands in one of my cars that had large Webers, nasty cam, she thought it was going to be hard to drive since it was always popping through the intake, had a snarly exhaust note, was generally a beast, but then was surprised when it drove better than her stock injected car.

I wonder how a larger plenum that would give a little room around the runner entries for better breathing/filling would help performance while still using the stock runners?

Oh,yeah, the runner is about 42mm, up on top there; I was thinking of the actual port, right before it splits off into the individual valve runners down on the head, sorry about that.
I was sort of dissapointed when the port was smaller, but it all works pretty good regardless.