Resistance is futile - The story of the borg.
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Author:  to4garret [ Tue May 22, 2018 1:20 am ]
Post subject:  Re: Resistance is futile - The story of the borg.

So, this thing is getting more play time recently than it's had in the last 10 years, and by that I mean it's been driven a few times each month :)

A few minutes from home on one of the recent drives the check engine light flashed up, which surprised me as I forgot I actually wired it up when I swapped ECUs. The error reported by PCLink was AN Volt 5 Short to Ground and AN Volt 5 is the TPS channel. A little look later showed that the TPS mount on the TB has cracked and fallen off... too much thong!


This ticked me off a little as I spent extra on a local Aussie product thinking the reliability would be better in the long run over an eBay jobby but in the end it was an easy fix, I just drilled and tapped the TPS mounting holes into the TB.

The shitty old single synchro KM221 gearbox hates shifting above 6,500rpm in 1st & 2nd and I hoped by lowering the RPM limit in those gears it will add some consistency to the shifts under power. I followed the Link ECU instructions for enabling and testing Gear Detection in the ECU, which is just RPM vs VSS and it's is working well, good enough to use as the main input for a Gear Dependant RPM Limiter.

Other minor changes, ECU now controls the thermo fans and that keeps the idle much more stable when the parasitic load comes on. I also have the ECU setup to run the W2A pump and Thermo's all the time when the Key is in RUN, ECT > 75c and the Engine Stopped, this seems to help the cool down and limit the heat soak on the barrel cooler.

I also did a compression test just to check general engine health, which came out at;

COLD 155, 157, 158, 153
HOT 163, 161, 160, 159

...and that is darn good as they're 165psi new, happy days!

With a recently return to reasonable reliability, I spent a day up in the hills following a bunch of other 80s/90s Mitsubishi's tragic's. The weather was an amazing 26deg, no wind - made the day really enjoyable considering there is no A/C in the car. :rotflol:


There are a few more things on the list of ECU changes, but i'm not really game enough to enable Launch Control & No Lift to Shift my self as there seems to be so many options for me to fruit and banana things up. I'm thinking I will just organise another dyno session over the winter and have a few more PSI added and smooth/lean out the AFR's a tad. Its Logging over 10.5:1 under boost which is a little rich and means I'm hitting 80% duty on the 800cc injectors.

Speaking of boost... I do wonder what the HP limit of the stock short block is? the turbo is supposed to be good for 600HP at the crank at around 27psi and I’m making 300HP ATW on 18psi right now and the turbo is rumoured to really start ramping in efficiency after 22psi.

This could be fun.

Author:  89Mirageman [ Thu May 24, 2018 11:42 am ]
Post subject:  Re: Resistance is futile - The story of the borg.

Thanks for the update and looks like you got to cruise with some nice rides.

Author:  Flying Eagle [ Sun Jun 03, 2018 11:23 am ]
Post subject:  Re: Resistance is futile - The story of the borg.

What a strange thing to happen to that TB! Never would have thought I would see something like that, but more like a bent shaft or something. See something new while you regale us with tales of the old (car). Yussss!

Author:  to4garret [ Sun Mar 17, 2019 1:53 am ]
Post subject:  Re: Resistance is futile - The story of the borg.

I've been driving this occasionally and I am definitely starting to feel old. Its loud, stinky, hard to shift, hot, light switch power delivery and basically everything a modern car isnt. I still love it though and i do need to use it more.

I have been a little busy with it, there is an up coming Mitsubishi vs Subaru drag day at the Motorplex on the 13th March so i thought i might as well see if I can make an appearance. I had a list of things to improve after my last visit to the 1/4m, like adding launch control, flat shifting and more boost.

Finally spent a few hours in the dyno booth last Saturday while it was 39c outside, lovely. but it was very productive. The car left with an extra 50hp atw at around 23psi but also has launch control & flat foot shifting setup.

The "No Lift to Shift" is really the winner here with boost between gears changing from 3s spool, to around 1.6s. This is a huuuuuge improvement between shifts as can be seen in the dyno timeline below.


There were a few touch up's after that graph and the car feels pretty good. I am aiming to get some seat time this weekend before the event next Wednesday and I am feeling confident the previous PB of 12.9 @ 112mph will fall.

Author:  to4garret [ Sun Mar 17, 2019 1:54 am ]
Post subject:  Re: Resistance is futile - The story of the borg.

Took this out for a good strop today to make sure i could actually drive it after the tweaks to the tune.

It kept hitting boost cut in 1st & 2nd once it was making 21psi even though the actual cut was set at 26psi. I hunted the ECU for any correction that could account for that (ECT/IAT etc) but everything was zero'd. Only thing i can think of thats causing the cut is the boost ramp rate and the ECU being a bit conservative with cutting the fun early thinking it will prevent an overshoot, but there is nothing i can see to change that behavior. I think i will just change the boost limit to a dual map with ECT & RPM and set a high limit between 4-5krpm, that might work.

Another unanticipated behavior, is that the launch control is triggered from the clutch switch, which is just a modified brake switch. When sitting there bouncing off the limiter the clutch pedal bounces around as well - not so much of an issue until you are rolling and the RPM limit bounces around 6k & 8krpm. I will see if i can jimmy up a spring to hold the pedal back.

Looking good for Wednesday though, here is hoping i can actually pedal it on the day!

Author:  to4garret [ Sun Mar 17, 2019 1:55 am ]
Post subject:  Re: Resistance is futile - The story of the borg.

Well had a fun night racing, drove there and back which is a bonus.

Took quite a bit to get used to driving with the NTLS & LC enabled - the gearbox really hates life now and really isnt cut out for fast shifting.

Set a new PB of 12.700 @ 187kph, 60ft 2.007 but spent 1.886 seconds of that on the clutch trying to get it into gear (or grinding it in)


clutch switch is the lower green line (DI 6 - GP Input), when high - clutch in, low - clutch out.

Author:  to4garret [ Sun Mar 17, 2019 1:56 am ]
Post subject:  Re: Resistance is futile - The story of the borg.

Stock take time!

Over the years if i spied some parts for sale and it was something worthwhile i would just add it to the collection and i've amassed quite a collection of "shit". One of the collected items was a full driveline from a 1990 Series II Cyborg that came up for sale which had front & rear mechanical LSDs and was 3.545 ratio! this means I had an upgrade path through VR4, GSR & EVO 1-3 components, plus spare drive shafts and axles which just are not available in Australia.

Anyway, i went part picking in the garage and the only time i've been known to use oven cleaner is to make it snow on driveline parts.


hose it off with a pressure washer and it does a great job - If you dont get wet you arent washing properly.

Found the rear diff, very small amounts of surface rust on some of the trailing edges of the crown - nothing that some wet & dry wont fix.


Turns out i had two steel case transfer cases, one is a 22 spline input and the other 23 spline input. I checked the ratio and they seem the same but im not sure if there are other difference between them apart from the input shaft spline count - i'll plan to use the 23 spline one.


Now the W5M33 box was really dirty inside, i stripped it down to get right into the guts for cleaning and one thing i noticed was how much black crud was over the inside. i havent seen anything like it on previous gearboxes that i've stripped but i think it could be due to the front LSD being a plate type and shedding more particulate into the oil.


I am not totally sure what type of LSD the front one supposed to be, i cant visibly see the plates but can get a peep of quite a few spider gears (at-least 4)


And there is no cross-bar in the middle.


With the W5M33 dissembled for cleaning and inspection i decided to pull one of the KM221 down as well to do a comparison. I find it quite interesting the differences between the gearboxes as they really are (pun!) an evolution of the design. the cases are essentially the same with the main change being the center differential drive being centralised to spread the load across the bearings better, but this means that the main drive for the center diff changes to 3rd gear from 4th gear in the KM series.



This is interesting as W5's have been known to be quite weak on 4th gear and comparing the gear size between the two generations shows the KM has quite a substantial 4th gear - probably meaning it could support more than the 600hp a W5 4th gear can.

but i digress and now that i've pulled the W5 down i can see it doesnt have double synchros on 2nd & 3rd like i had hoped so I have a few options from here;
  1. Learn how to inspect synchros for wear and see if the W5 is going to be good enough to use.
  2. Search for a later model W5M33 with double synchros and built a frankenbox, seems a lot of the supply is drying up though.
  3. Order a staged upgrade kit from TMZ in the states and have it installed locally.
i'll have a beer on it i think.

Author:  Flying Eagle [ Sun Mar 17, 2019 6:33 pm ]
Post subject:  Re: Resistance is futile - The story of the borg.

Looks like you have been busy!

It’s good you have been working with TMZ for parts and upgrading.

Have you seen the torque capacity chart that TRE Team Rip Engineering has listed for Mitsubishi transmissions?

I keep looking at that and wonder with amazement how long some transmissions have lasted over the years.

It’s good you can devle into transmissions tear downs with a degree of confidence.

I just ordered a whack load of tune up equipment to try and get some consistency back into my setup and a change to a 482 maf with 3” mandrel bent to 2.x inch intake snorkel to the Evo3. I’ll have my transmission out soon if all goes well, to swap the 8.2lb flywheel for a 12 lb chromoly and a step back to a lighter pedal feel clutch plate and disc combination that can still handle 300-320hp/tq.

Author:  to4garret [ Mon Mar 18, 2019 7:28 am ]
Post subject:  Re: Resistance is futile - The story of the borg.

I would much rather play with engines than transmissions, the gear oil stinks too much!

I havent contacted TMZ yet, but have read the website a few times. Shipping a gearbox to US & back to AU would be quite cost prohibitive so my current thoughts would be to get the parts shipped here then do the assembly locally if i can get enough of the installation specifications as well. I only have one W5M33 so i may need to invest in it more than i thought.

I cant believe how hard bits are becoming to find, my brain still thinks these are everywhere - but its not the case any more.

Good move on the heavier flywheel i felt it made the car a bit more drivable. Dont make the same mistake i did and assume the step height is correct though - even when new, took me months to find that after replacing pivot ball, clutch fork, master, slave, lines... (cant be the flywheel, thats new and by a name brand)

Author:  Flying Eagle [ Mon Mar 18, 2019 7:06 pm ]
Post subject:  Re: Resistance is futile - The story of the borg.

Excellent point on checking step height. I want to find a manual gauge versus digital because I don’t trust cheap digitals with really accurate measurement like that. I suppose I can always pop by a machine shop too and bring some coffee for the guy.

Yeah, doesn’t take much to do the work locally. I used a chart that showed preload on the gear sets with regards to setting up how much when the case is tightened down. If you have ball and cage diff bearings then there won’t be iirc, but for the rest it can be a matter of play or preload and how much.

Seems there is a gold mine of information in this thread and others linked there: Tuners https://www.dsmtuners.com/threads/setti ... ds.442999/

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