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The Lexus Saga begins

Posted: Fri Sep 11, 2015 11:18 pm
by Boetamac
Evening Gents....

I took delivery of my prewired 1uz vvt-i to go into my 1996 2,8D DC 4x2 Raider.

i have it running on a stand in my garage. It has two oil leaks i am attending to now.

In my preparation for fitment i stumbled upon a few issues:

1) How do i get an aftermarket rev counter to function properly?

2) What options do i have with the propshaft? Where do i fit the slip joint?

3)Is it necessary to join the left and right bank's exhaust? Do they have to join and then exit?
Do i have to keep the cast manifolds? And what size pipes do i use?

4) I am keeping the 5spd autobox, how do i get the speedo to function?

5) On the throttle body the cable movement is only about 30% of flap opening. how do i get the cable to give full open throttle?

any advice would be highly apreciated

Re: The Lexus Saga begins

Posted: Sat Sep 12, 2015 8:00 am
by Knuppel
I will be watching your pogress, i am busy with a 87 hilux 4x4. Have not bought the motor yet but the negotiations are along way down the road already.

Re: The Lexus Saga begins

Posted: Sat Sep 12, 2015 8:26 am
by Knuppel
Here is some info i found on the net regarding the exhaust as i have been pondering the thought myself and have had many answers to the question. The info below sounds more plausible and you can make a decision from there. One audible effect of making cross-over pipes , not mentioned below, is that the sound comming out is very even and it does not sound like a burbled idling misfiring highly tuned Nascar V8 engine.
The firing order of all production V8s, regardless of make, has one cylinder in each bank that will fire within 90 degrees of crankshaft rotation of another cylinder in the same bank. This occurs twice during completion of the entire firing order. These two cylinders will be exhausting almost simultaneously into the same exhaust manifold system.

Full-length four-tube headers help separate these pulses until the collector is reached. If this is a full race car running "open exhaust", you will notice the collector dumps into a short open pipe at least 2.5 times the size of the header pipes, or the header pipes dump direct without a collector. This is done to avoid the conflict of pressure caused by the timing of the 2 counter firing cylinders, which will create back pressure and degrade torque, horsepower and general performance, especially at higher RPM.

On a full exhaust system, after the header tubes dump into the collectors, the two close firing cylinders are fighting each other for space in the collector and exhaust pipe. The result is reflected pressure waves traveling back up the exhaust system, backpressure, lost power and poor economy.

At the same time two cylinders exhaust in one bank, there is no activity in the opposite bank. The traditional H-pipe equalizer allows some of the excess pressure to bleed over to the 'quiet side' of the exhaust system, resulting in some low and mid-range torque improvements. At high RPMs, however, in traditional exhaust systems, the gases cannot bleed across the H-pipe fast enough to help power significantly. Performance systems with the H pipe design, attempt to over come this by using a shorter cross over pipe which is also slightly larger in diameter as the main exhaust, then would be used in a standard exhaust.

To overcome the power loss of "over loading" the H pipe design, Exhaust manufacturers came up with the X pipe design, which features a tangentially Siamese crossover junction to synchronize exhaust pulses. The X-pipe concept is to split the flow in the crossover junction, so the pressures on both banks will be equal and pulse-free after the crossover, regardless of the rpm. Volumetric efficiency and power are therefore improved at all engine speeds. The negative aspect to the X pipe design is, because of the crisscrossing of the flow stream, harmonic pulsations will develop on some systems at certain RPMs, which will be perceived as a buzzing or humming sound.

A newer concept is a "Channel Pipe", where as two pipes are welded together in parallel with a baffle in between them which allows for mismatched pressures and pulses to cross to the idle side while allowing full, uninterrupted or redirected flow of the exhaust stream through the system.

Also... There is yet another option.... The MAC Prochamber.

It looks like a box, or a muffler where the 2 header leads enter one end and then exit the other in the location of the H or X pipe.

It is essentially a combination of all three basic designs I discussed, incorporating the crossover flow of an X pipe – the open buffer of an H pipe and the passive pulse control of a ported baffle channel pipe. MAC is the ONLY maker to have this design.

Basically it combines the exhaust into a single box, where the 2 inlets extend into the box a few inches to prevent reversion and open dumping exhaust into the box. The outlets are flush with the back of the box and there is a baffle between the sides with ported slots directing the flow of the inlets to cross to the other side. The Box holds backpressure at a steady rate, which eliminates scavenging.

There are many who believe the Prochamber will give increased performance values. Everyone using them will tell you they make a deeper yet quieter tone to the exhaust note.