The Rwd 2Az-Fe Thread.

[Sam_Q]

ah I see, that would make a more direct transfer of power from the piston to crank as well as reducing piston wear right?

 

such a simple concept but I never thought of it

[irokin]

I think so. Mind you I could be completely wrong, I'm only imagining the dynamics and who knows, maybe its offset in the other direction(!)? You could achieve a similar effect by running a really large rod ratio so why didn't Toyota go down that route? Then again, perhaps they did that as well.

[LittleRedSpirit]

Rod ratio isnt super on a 2azfe.

 

1azfe is better, if you wanted a revver Id just build one of them. Same length rod with a shorter stroke, the 2az id the stroked version. id assume the Brian Crower 2.7 kit is good for a low rpm boosted build but not a revver. These motors are not designed for peak rpm. From the factory they have long inlet runners (400mm plus), offset crank, a balance shaft with plastic gears. Narrow bearings in the head and mains to reduce friction. The 2az has the balance shafts, the 1az doesnt, so If you wanted to delete them you just get one of our special rollaclub friends at Toyota to scrounge a 1az lower crankcase and swap it over, because it doesn't girdle the crank, you can just swap it over with no ill effects except deletion of the entire balance shaft assembly. You would then be required to rebalance the rotating assembly. There is a company in the US sleeving the shit out of 2azfe blocks for boosted applications. I think they are called Dezod Motorsports. There's a few actually. I'm sure someone in Aussie will start doing it in time. Darton make the Parts.

 

Edit:

 

Just worked it out, the rod ratio for a 2azfe is 1.55. 1azfe is 1.73. Much better due to the reduced stroke.

For comparisons sake, the 4age is 1.58. 3RZ Hilux 4 cylinder is 1.54, and they don't much like revs.

Edited September 1, 2011 by LittleRedSpirit

[irokin]

Now that blocks more like it!

[LittleRedSpirit]

You can buy a built bottom end for around $4000 US with the sleeves installed and forged pistons and rods. Stock crank is decent like most Toyota motors.

 

I got the tube I need for my inlet manifold now, I just need to make some kind of plate to mount the itbs. Might have something lazer cut to suit once I have the throttles I need.

[Sam_Q]

You can buy a built bottom end for around $4000 US with the sleeves installed and forged pistons and rods. Stock crank is decent like most Toyota motors.

 

I got the tube I need for my inlet manifold now, I just need to make some kind of plate to mount the itbs. Might have something lazer cut to suit once I have the throttles I need.

 

laser doesn't do more than a few mm in aluminium. Water-jet cut is what you want

[LittleRedSpirit]

I'm liking the look of these itbs.

Edited August 7, 2017 by LittleRedSpirit
image fixed

[Sam_Q]

they look nice however that works out to $780 before shipping

 

what about those cheapo OBX throttles? they look like they used a modified 20V casting

[LittleRedSpirit]

Borrowed from Jenvey site...

 

Which type of throttle body ?

 

Twin bodies are the most straightforward solution for production engines, direct-to-head where available, or via a suitable manifold.

Direct-to-head-bodies represent the simplest and neatest solution. They are harder to match to the inlet ports if this is required for the engine in question but have the advantage of being angled for best results, unlike a carburettor manifold.

Single bodies represent the no compromise solution, particularly for competition use. The seperate manifold is easily matched to the inlet ports and the best mixture path is guaranteed. They are also available in fully tapered bore and twin injector types. Mounting, balance and maintenance are naturally more involved.

What is the best throttle body diameter ?

 

Factors influencing size are; Power output, RPM, cylinder head design, cylinder capacity, position of the throttle body in the inlet tract and position of the injector.

 

Choice of bore size is a balanced compromise resulting from the following;

1) A larger bore leads to lower flow resistance, but obeying the laws of diminishing returns.

2) A smaller bore leads to better throttle control and response (never underestimate) and improved fuel mixing.

3) The system should be considered in total - from (at least) trumpet flange to cylinder and proportioned accordingly.

 

Basic references for BHP per cylinder, assuming ca 120mm from butterfly to valve head and a max of 9,000 rpm are;

Up to 30 BHP - 30mm, up to 33 - 32mm, up to 39 - 35mm, up to 46 - 38mm, up to 51 - 40mm, up to 56 - 42mm

Up to 65 - 45mm, up to 74 - 48mm, up to 80 - 50mm, up to 87 - 52mm, up to 93 - 54mm.

These power figures may be increased by up to 10% in a purpose designed and well proportioned system.

As butterfly to valve distance increases, butterfly size will need to increase in proportion to system taper and vice versa.

Lower revving engines and those with injectors placed before the butterfly will generally accept a larger body.

What is the correct overall system length?

 

Induction length is one of the most important aspects of fuelling performance engines.

In our experience an under-length system is the greatest cause of disapointment, with loss of up to 1/3 of power potential. There are a number of good books on the subject and the serious developer is referred to these and, in particular, dyno trials. A guide figure, from the face of the trumpet to the centre of the valve head is 350mm for a 9,000 RPM engine. Other RPM are proportional i.e. for 18,000 RPM the figure is approximately 175mm.

 

Any air feed system to an airbox or filter can have a large effect on the power curve and must be considered carefully particularly if the airbox is small.

The induction system is part of a resonant whole from air inlet or trumpet to exhaust outlet and the ideal length is heavily influenced by the other components.

What is the best position for the butterfly?

 

The butterfly is an important aid to fuel mixing. When positioned too close to the valve this advantage will be lost whilst positioning far away may lead to a loss of response.

As with the injector position (see below), higher RPM demands a larger butterfly to valve distance. A practical minimum figure for a 7 - 9,000 RPM engine is 200mm, whilst the maximum is dictated by the need to fit an air horn of reasonable length to achieve a good overall tract shape. One solution to this apparent compromise is the use of bodies with fully tapered bores which, in effect, extend the trumpet distance beyond the butterfly and into the manifold. For very high speeds above approximately 15,000 RPM, the ideal butterfly position is only just inside, or even outside the trumpet and a point is reached where a taper is no longer sufficient for good tract shape. For these circumstances we can supply bodies with the exponential trumpet shape machined into them as a special service, or barrel bodies which, by their nature, must be purpose designed in conjunction with the cylinder head.

Where is the best place for the injectors?

 

Where one injector is to be used per cylinder the best compromise position is immediately downstream of the butterfly. This gains maximum advantage from local turbulence and gives results surprisingly close to the optimum at both ends of the rev-range. This is the recommended position for most applications.

For performance at low RPM, economy and emissions the injector needs to be close to the valve and firing at the back of the valve head. This is the favoured position for production vehicles.

For higher RPM (very approximately 8,000+) the injector needs to be near the intake end of the induction tract to give adequate mixing time and opportunity. The higher the RPM, the further upstream the injector needs to be. As a result, use of speeds above approximately 11,000 RPM may give best results with the injector mounted outside the inlet tract altogether (see our remote injector mounting). It is common to fit both lower and upper injectors in such a system to cover starting and low RPM, as well as high speeds.

What is required for a complete fuel injection system?

 

Besides throttle bodies, linkage and manifold (if required) typical components are; A management system, wiring loom, fuel pump, fuel pressure regulator, fuel injectors, appropriate plumbing, air horns and a ducting / filtration system for the incoming air.

What type of injector?

 

Dimensions: All Jenvey injector mountings and fuel rails will accept either the standard 'O' ring mounted injectors for 14mm bores as supplied by Bosch, Weber, Lucas, etc (64mm between 'O' ring centres) or the shorter 'Pico' style injectors (38mm between 'O' ring centres).

There are a number of other injector types, using the same 'O' rings but with different lengths. These can be used on our twin throttle bodies with ease, but may require different fuel rail mountings on individual bodies. Please specify which you are using when ordering throttle bodies and fuel rails.

Flow-rate: When fitting our throttle bodies to an otherwise standard engine bear in mind that increased power means increased fuel demand and the original equipment injectors are therefore usually inadequate.

What manifold to use?

 

When injecting into the throttle body (e.g. our types TB, TH, TF, TA, direct-to-head and SF, SS or ST//1), most of the mixing occurs within the manifold section. It is therefore important that the manifold is suitably proportioned to evenly accelerate gas speed and thus help fuel mixing and distribution. The straighter the run in to the ports the better. A manifold which curves in the same direction as the valve throats is preferred to one which causes the flow to pass through an "S" bend.

What throttle potentiometers will fit Jenvey bodies ?

 

We use relatively popular mechanical interfaces for the throttle potentiometer. Popular types are; Colvern CP17 series (as supplied by Jenvey), Wabash 971-0002 and (via fitting kits) throttle pots from Novotechnik, Penny & Giles, Marelli and Weber. A number of production car throttle pots (e.g. Rover K series) will also fit directly to the bodies.

The Colvern CP17 throttle potentiometer may be mounted to either end of most installations and spindle rotation is typically 82o.

Can Jenvey bodies be pressure charged?

 

Jenvey bodies can generally be used with boosts up to 6 bar, although we recommend that you contact our technical department if boost of more than 2.5 bar or temperatures above 150ºC are expected. Some models require special treatment for high pressures and/or temperatures.

Can Jenvey bodies be connected to an Air Bypass valve?

 

Components and complete kits are available to connect the output from an ABV to throttle bodies. More information is available on a specific instruction sheet.

What is the best Air horn ( Trumpet / Stack / Bellmouth)?

 

The air horn serves three main purposes;

 

1) To convert the pressure difference between bore and entrance into air velocity with the minimum of energy loss.

 

2) To act as the interface between the induction system and the atmosphere, i.e. the point at which pressure waves change sign and direction.

 

3) To complete the system to the required overall length.

 

For ease of description the air horn may be considered in two parts; the 'flare' and the 'tube'.

The main job of the flare is to spread the low pressure zone over the largest possible area, to reduce local pressure reduction, whilst guiding incoming air into the tube with minimum disruption or induced vortices. The flare should be shaped to encourage air to enter from the sides but not from the rear of the mouth. This is achieved by either finishing the mouth with a sharp edge when the arc is a little beyond 90o from the air horn axis or by folding material back, parallel to the axis, when the arc is at, or just below, 90o to the axis.

The main job of the tube is to accelerate the airflow smoothly and progressively. This is best achieved by an exponential shape, i.e. one where the radius of curvature is increasing constantly until the angle of the sides matches the next part of the system, usually the throttle body.

It should be noted that the requirements for fuel injection and carburation do not always coincide and the best horns for one may not suit the other.

[LittleRedSpirit]

they look nice however that works out to $780 before shipping

 

what about those cheapo OBX throttles? they look like they used a modified 20V casting

 

 

TBH, I don't like the cut of their jib. I'm just not impressed and they are light on for tech. info on development of their stuff.

[19914afc]

Wow certainly done some researching there! Don't think you will be too interested in revving over 15000rpm?

[LittleRedSpirit]

No but the principles apply at any rpm.

 

I'm looking for a 400mm long runner and a 185mm distance from the butterfly to the valve.

 

Might have a look at my motor today to see how that idea positions the throttles.

[LittleRedSpirit]

So I had a fiddle with the inlet today.

 

I worked out the length I needed.

 

I'm looking for 200mm maximum from the butterfly to the top of the valve. The valve top is 115mm from the inlet face, so I need a manifold thats about 60mm long. If I were to use ST ITBs then this is what it would look like. Ive mocked it p with some lighter pipe than what I would us but that has the correct ID. I need about 12 degrees angle on the 1st and 4th port, and about 5 degrees on port 2 and 3.

 

The black paint shows where the butterfly needs to be and the lines on the piece of board show the 20v spacing.

Edited September 5, 2011 by LittleRedSpirit

[Sam_Q]

what about extending the tabs for the 20v throttles to have the same bore spacing?

[LittleRedSpirit]

Yes its possible but I'm not wanting to make every little bit. I could just convert to a traditional rail and lever linkage and put them wherever. I mocked this up just to see how far the ports would be angled.