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Discussion Starter #1
I am in the process of putting "Melow Yellow" back on the road after a few years in storage with the occasional drive.

My car in a 94 VR4 which I have owned from new. It has 134,000 miles and had a very comprehensive go through at 120,000 miles (120K service + new oil and water pumps, new A/C (compressor, evaporator and core inside the car), new drive shafts, new wheel bearings, suspension bushings, Tein coil-overs, AP6pot front brake upgrade, many new sensors etc.

It ran great but I got into track-days on bikes so didn't get much use.

About 4 years ago it developed a low idle and became difficult to start when hot. I got the fish smell from the ECU so guessed it was bad.

So now I have decided to put it back on the road and started with the ECU. The old one was fried as you can see from the picture. I was amazed that it even ran let alone run as well as it did.
 

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Discussion Starter #2
I got a flashable ECU from Jester which didnt fit my stock mounts. So after swapping e-mails decided to put the new ECU in the old box.

The old box needed 2 mounts making as the new Board s shorter and I wanted it anchored down securely.
 

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Discussion Starter #3
It took me a while to figure out how to fit the flash wire to pin 57 of the car side connector - my old eyes kept missing the pull out tab on the car side connector.

Anyway got it fitted, held my breath and hit the starter - and wow it fired right up with not even a full rotation of the motor! Impressed!

Took it our for a ride and the good news is that it pulls harder and cleaner than I ever remember it pulling.

The bad news is that as soon as I slowed down it became evident that all is not well at part throttle below 4000 RPM. It runs like only 3 cylinders are operating and idles at 4-500RPM.

So the original reason for the ECU - poor idle and occasional stall is still there and part throttle low RPM power and smoothness is worse.

I am swapping e-mails with Adam and getting the diagnostics sorted out on my laptop.

I am also beginning to think that the old ECU's "limp home mode" was masking at least part of what's causing the low RPM part throttle issues that I now have.

So I am now at the start of looking at the Idle Air Control system, the fuel pump pressure regulation and the fuel pump electrical feed - as each of these has been implicated in low idle and poor operation at low revs/part throttle.

And so my journey begins :)
 

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Discussion Starter #4
... and ends with a bump. I have juts been reading through the various archives and came across Jeff Luciu's (Stealth 316) write up on the Idle Air Control Servo. The symptoms and the ECU damage resulting from a shorted IACS is a very good match for what I have.

So before I brew up my new ECU i'll pull the IACS and given its done 134,000 miles already I'll replace it anyway.

SO Mellow Yellow is back off the road until my new IACS arrives.
 

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Discussion Starter #5 (Edited)
So here I am 6 years later (after starting and then exiting a whole new company) I have finally got Mellow Yellow back on the road after a couple of false starts.

I ended up going for a complete re-build and hired FFTec a local (Hayward, CA) Mitsu and DSM shop to do most of it. So first off, anybody in the SF Bay Area looking for a 3000GT specialist - Dave Womer at FFTec is the man.

The objective was a daily driveable track-day weapon for my loack road courses (Laguna, Sonoma and Thunderhill). So the focus was on drivability, lots of area under a big flat torque curve and manageable heat - i.e. the ability to run 30 minute hot-lap session in 90+ F heat.

3Si sourced me a new built stage 3 motor and built drive-train (braced, Torsen center, Quaife front, KAAZ rear). We went with a pair of 3SX Executioner V2 on it with 3SX Stainless headers. I believe the Executioner V2's flow similar to the venerated DR 750's. I also switched to an AEM V2 ECU with dual AFR and ditched the MAF. Added water/methanol and a S90 throttle-body. I went with dual side-mounts because I need to keep good airflow through the radiator for track-days.

So where we ended up (after several hours on the dyno') is a motor, drive-line and all the support systems to run at >700 WHP dialed back to just shy of 520 WHP (~620 crank HP).

I switched out the Teins for a set of Mr Mueller's custom Ohlins - and OMG what an improvement over the Teins!!

Braking is AP 6 pot up front and stock 2 piston MKII rears.
 

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Discussion Starter #6
The next job is to rework the front end to
1) significantly increase airflow through the radiator and intercoolers
2) route ambient outside air to the intakes
3) extract heat from the front and especially the rear turbo
4) incorporate a new under-tray and adjustable splitter. I still have operational active aero - so am hoping to incorporate the front dam actuator into the design and operation of the tray and splitter.

Then it will be off for for refreshed paint (over winter) while I re trim the interior.
 

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Discussion Starter #8

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Discussion Starter #9
Went for a 170 mile shake down run yesterday (Sat) and chose a route that included stop and go City driving, open freeway, grid-locked freeway and about 80 miles of open - out of the way canyons and hills around Nor Cal. Air temps started out in the high 70's and rose to high 90's by the end of the run.

Found a weird issue with the clutch, which started to drag after about 100 miles and got progressively worse as the day progressed - to the point that I need to shut the engine off to engage 1st and then it would creep forward with the clutch depressed (with the brakes off). 3 hrs after I got home, when everything had cooled down, it was working fine again.

I'm going to work through the usual suspects (check bracket pedal bolts, adjust the pedal free play, bleed the line etc. However, given that it cleared when it cooled down, I have a feeling that the extra heat from the rear turbo maybe cooking the clutch fluid. So I may need to insulate and/or relocate the clutch fluid lines.

More on this later as I figure it out.
 

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Discussion Starter #11
Were you in the Bay area this whole time? I just moved to LA after ~4 years in the bay area. Woops!
Ha yes, I have lived in Orinda, CA for 25 years. I was pretty active in the 3000 GT community in the 90's when we were just starting to figure out how to get more out of them. I started racing Spec Racer Fords in the early '00's and switched to bikes for track days and the occasional "old man's race" and got an EVO IX as my daily driver in late '07.

I could never get my head around selling the VR4 so it sat in storage for a few years. Then I decided to get serious about putting the VR4 back in decent shape - now that we had access to decent electronics and suspension.

Here is a much younger me at my first run at Laguna Seca in '95.
 

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Discussion Starter #12
Update, dis about 200 miles of shake downs over the weekend. Its currently tuned for 19psi max, while we fine tune it and work on improving heat management. My tuner had a calibration issue with the dyno and it turns out that we are getting ~600 lbft that we thought we were making at 19psi - the relatively fresh upgraded clutch was easily overwhelmed at 4,000 RPM in 2nd and 3rd.

I need a clutch set-up that will hold 700lbft from a stiffly mounted motor AND be usable in stop and go street use.

We did the research and decided to go with a Clutch Masters 850 street and track 2 disk set-up. As the name implies that's good for "850 torques".

I am aware that CM twin disk clutches had mixed reviews when they were first used on the platform 9 or so years ago - but the EVO and DSM guys seem to be getting good results with them - so fingers crossed.

On the plus side, I'm pretty amazed that we are getting ~600lbft at 19 psi of boost! I'm really looking forward to getting on with the airflow/heat management mods and seeing what we can get with 25psi!!
 

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Wow, you had the car since was the thing back in the day, brand new, that's awesome, so you noticed that the car worked better in stock form just by going chrome/99 ecm?

I have read several posts/reviews about just swapping the ECU with no flashing or customizing and they get better idle/mpg/response.
Have a 99 there.. just need to build the boomslang for my 94 or maybe to my 91..
 

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Discussion Starter #14
Wow, you had the car since was the thing back in the day, brand new, that's awesome, so you noticed that the car worked better in stock form just by going chrome/99 ecm?

I have read several posts/reviews about just swapping the ECU with no flashing or customizing and they get better idle/mpg/response.
Have a 99 there.. just need to build the boomslang for my 94 or maybe to my 91..
Yes its become something of a family pet lol.

Yes the Chrome ECU was a plug-in improvement - but the OE ECU was bad which is why I went with Chrome originally. Adjustable ECU boost control under Chrome is a big benefit as well. We got it up to 390 WHP with minimal mods under Chrome but turns out the 25 year old single knock sensor had gone bad, so I ended up throwing a rod.

Went with AEM V2 with full closed-loop control off dual AFR and knock sensors for the rebuild.
 

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Discussion Starter #16
I like your dedication, it's going to be interesting to see how your car progresses. By the which AEM version did you go with?
AEM V2 with Stage 3 Snow Performance water methanol.

We are struggling with high IAT's with the current SMIC setup. but I really don't want to switch to an FMIC as that will hinder engine cooling for road course lapping.

IAT is >180F at just 19lbs of boost at 7400RPM measured prior to water meth injection. That's measured on the dyno so it may be less when we are getting on-road airflow. I'm planning on adding a secondary IAT in the plenum to measure post water/methanol charge temp so we can more accurately map ignition advance and have additional failsafe if the charge temps get too high.

We will be data logging all the time from now on, so should have real world data.

Hopefully the 99 nose, new ducting and hood vents will help bring this down significantly.
 

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Discussion Starter #18
Are you running sidemounts with bell cores?
CX Racing SMICs, not sure what the cores are but they are >>2 time the volume of the OEM SMICs. I don't think they are getting enough cooling air, with the current nose and OEM ducts.
 

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Discussion Starter #19
The dyno's calibration is off but given that my clutch lasted 2 days, we believe we are making >>500lbft and >>500HP at the wheels. So its lots of fun :)
 

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I'm running the Gene sidemounts with 10" high cores from Bell Intercoolers. I believe Oohnoo here on the forum makes similar intercoolers from Bell cores to this date. Those have worked very well for me but as you say I run the 99 front with custom ducting.
 
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