5MGE expert opinions valued - inlet manifold design and room for improvement

[SmokinSquirrel]

Hi Toymodders,

I'll be doing a rebuild of my 5MGE in my X73, I want to just do a pretty standard rebuild on the long motor, with just a cleanup of the chambers and anything that doesnt need parts (I am handy with a diegrinder etc)

My inlet manifold is cracked and considering I want to run a megasquirt or similar Ive toyed with the idea of ITBs.

I managed to score an EF Falcon 4.0L engine for free, and it has the Broad Band Manifold, it has a 65mm throttle body running the same direction as the toyota item, and the 6 butterflies inside the snail of the manifold, which change the length of the inlet tract at 3800rpm on the falcon.
I have a furnace almost up and running and will be starting to cast my own alloy parts this year so its only time, BBQ Gas and my imagination that limits me.

Question is, would I benefit from the low end torque the Broad Band Manifold can help to achieve? Or does the 5MGE prefer a fixed length runner?
I would only need to make a pattern and cast a new lower section to change the manifold to suit the 5MGE.

Am I wasting effort here?

[CrUZida]

Depends what your goals are with the car?
Generally speaking though, yes, you are wasting your time and effort. And to an extent the same goes for the rebuild.

An engine conversion may cost a little more, but will yield a better car over all.

As soon as you start going into uncharted territory, you are opening yourself up to a potential world of pain.
Sure, it may go super smoothly, but it may not. It may ruin the driveability of the car, you may spend the next 6 months trying to iron out the bugs (ie the TPS will be different, and might upset the ecu. The 5MGE ECU has no internal trigger for the internal butterflies, so you'll need to work out a way to trigger it. You'll need to find the ideal RPM to switch it all, the RPM value may differ depending on throttle position, will the stock tuning handle it? etc etc).

If this was on a 2014 car, I could see the temptation. But not on a 30 year old car.

If you want to see some ideas on what people have done to the 5MGE, head to the celicasupra.com forums. The Seppo's love toying with the 5MGE instead of doing an engine conversion.

[SmokinSquirrel]

Thanks Cruzida, I'm trying to not do an engine swap because I've already got a w50 and bellhousing to suit the M, I have the tools and skills to rebuild the donk.
I wont be using the 5MGE ECU because I want to run a MAP sensor anyway and get rid of the AFM.
ITBs are still a reality at this stage.

Sure a JZ will yield more power, a UZ would bring some goodness with headaches, but I'm in love with the M, call me a fool or a stick in the mud, I love my 5MGE

[CrUZida]

If you are going ITB's, then you may as well get high compression (11:1), and bigger cams, as well as substantial head work. Otherwise you'll get minimum benefits out of the ITB's, apart from a bit better throttle response.

I personally wouldn't put a modified 5MGE into an MX73. Its not a chassis designed for performance. I've had a modified MX73 in the past, and its a much much nicer car when its used as designed, ie as a cruiser.

[oldeskewltoy]

be careful just digging in with a die grinder...

Here is a 5MGE I recently ported.... http://hachiroku.net/forums/showthread.php?t=36773

intake side..



exhaust side...

[SmokinSquirrel]

I did read your thread Olskool, very informative. And Cruzida, the itb route you're right, for the minimal gains without cams, etc would be a bit of a wank. Compared to Celicas the cressida is a heavy chassis for the 5M, and id rather reliable driving time. Still toying with the idea of the ford BBM as:
1: I have it
2: It won't cost me much moneywise (yes I'm a cheap c**t)
3: Even with standard cams I'm sure the efficiency of the 5MG would be better than a single cam Falcon boat anchor
4: On the falcon forums, guys retrofit to older models (even the 250 X-flow) using a shift light switch and an actuator on the butterflies
5: It hasn't been done, and I like to think differently

Once I get started ill post pics n stuff into my build thread

[boxh34d]

Is it worth looking at how Toyota switched the butterflies in the NA 7M out of the supra?
Not comparable to the falcon I know, but could give some ideas on parameters used on that engine rather than just straight rpm switching.

Also, didn't one model of 4A run something similar?

[SmokinSquirrel]

Thanks boxh34d, ill be looking into that. But the simple rpm switch does give me adjustability to match the torque curve. Falcins open at 3800rpm, which acts upon electric signal over vacuum solenoid, ill look into the Toyota way of doing it.
Taking the Kaizen principle to a new level, lol. (I used to work at a Tojo dealership)

[MA61 Turbo A]

Hi,

This is the 5mge in my crown,



For all the work that iv'e done,

1mm oversize 9.2 hypatec pistons
fully balanced
harmonic balancer machined to only run 7 rib belt
5 thou off block
35 thou off head
Comp ratio close to 11:1
Head ported
Stock cams
Tuned length 6-2-1 extractors, 2.5" exhaust
Bottom half of factory inlet with fuel rail and injectors, 1.8ltr plenum with black top throttles.
Adaptronic ecu.

I built this for the look, not for how it goes.



I have no issues with low down torque, most of my driving is at or below 3500rpm. This is with 3 speed coloum shift and 4.88 dif gears.

If you cast a new lower half you will have to re-do all the injector mounting.

Hope this helps,

Brad

[boxh34d]

Holy shit brad, they are some niiiiice pipes! The rest looks schmick too, but wow.

[SmokinSquirrel]

I concur on the pipes, nice work brad

My lower manifold is cracked at no 1 flange, so replacement or repair is my only option.
Casting this myself means I make the pattern as well.
I'll have the original manifold as a guide for runner and injector placement.
So I see you're running Quads Brad. Did you run a MAP sensor and what type?
I'll be running the falcon broadband intake system as id be in its effects on something that's not a falcon, lol

[MA61 Turbo A]

Hi,

Map and tps, Map sensor is built into the adaptronic ecu.

[SmokinSquirrel]

Thanks MA61, ill look into their wares...

[SmokinSquirrel]

WP_20150319_13_55_24_Pro.jpgWP_20150319_13_55_24_Pro.jpg

Decided on scrapping the idea of the falcon manifold, and going ITBs, I managed to salvage one good piece from the falcon manifold, the butterflies from the manifold and the shaft
One end can be shortened through machining to get the butterflies symmetrically spaced.
I'll just cast a throttle body assembly and the manifold.

[oldeskewltoy]

I'll just cast a throttle body assembly and the manifold.

need to keep an eye on this thread..........


brainfart.... Broaden the torque curve... telescoping manifold?? to pull it off, casting would be used to support the mass, but an inner, thinner walled pipe would be needed so transitions from one telescoping section would be minimal


Additional thoughts.... the 5MGE intake valve weighs in @ a whopping 92 grams... while the exhaust valve isn't exactly svelte @ 80 grams... custom lightweight valves would add rpm capability.....