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That's really weird that the MSD box would do that, it must have some offset built into it which I can't imagine is not user adjustable?

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Discussion Starter · #622 ·
That's really weird that the MSD box would do that, it must have some offset built into it which I can't imagine is not user adjustable?

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If it's adjustable then it's eluded me for a very long time lol
 

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Discussion Starter · #623 · (Edited)
Wanted to give an update since it's been several weeks and I've been way too busy to keep up. I quit my job at the Mitsubishi dealership and started as a field tech for a cable company. Definitely not something I envisioned getting into but has been a much needed change and I'm loving it so far. Between having a work truck with all gas paid, free services, better benefits, and LOTS of room for advancement it will be a company I can see myself with for quite some time.

A friend's V6 3G has been stuck in my garage for the last 10 months and will finally be leaving within the next week or two. Initially it was a head gasket replacement job (combustion leaking past the firing ring causing overheating) and turned into rebuilding the turbo, rewelding parts of the hot side piping, replacing axles and the half shaft bearing, rewiring, etc. Just an absolute nightmare overall but I wanted to do it right so we could avoid future issues. It was only something I'd work on in my spare time when I'm not messing with my own car. I'm glad it's coming to an end so I can cut ties with it and have my garage back! Then I have 2 other 3.8L swaps waiting to get done o_O

Now comes the updates on my 3G. I've been plagued by auto trans issues ever since the car made over 350whp. The factory added several "restrictors" to slow fluid flow to each clutch and create smoother shifts but in high power applications they cause big delays that enable slippage. It's a fine line between comfort and performance when it comes to changing the restrictor size. Fluid pressure in 2nd and 4th was also kept low and different style pressure valves without an orifice were used (seen below). I found that by opening the restrictors, switching to the orifice valve, and increasing spring rate on the 2nd pressure valve it increased pressure to the 2nd clutch. I also adjusted the manual valve which raises overall pressure to all clutches. My trans oil pan didn't seal up very well so a brand new one took it's place!






In order to see these pressure differences I needed the Mitsubishi adapter and gauge to test at the ports on the case. Only problem is the adapter is discontinued so I had to make my own. I started by making a banjo bolt that matched the test ports thread/pitch. Then I welded a banjo fitting to a pipe thread fitting to adapt it to the gauge. My weld is holding over 200psi so that's awesome to see (y)



The last piece to the puzzle was finding the shift pressure tables in the ecu. I can control how soft or hard it "pushes" into the next gear. I previously couldn't put any power through 2nd and with all these changes it's seeing over 600whp without slipping! I was able to do a 1-3 test pass without lifting the throttle and it really keeps you back in the seat!

Now for the bad news... when I replaced the crank I assembled the main bearings too tight and they started to bind. Luckily I found that before it was too late and can fix it. The girdle is off and the crank journals look ok. I'll check clearances with a fresh set of main bearings and if need be pull the engine to have the crank machined.

Last update is I picked up another project... a John Deere riding mower that needs a head gasket. Luckily it's an easy fix and was a great deal.
 

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First let me correct you, that's not a JD that's just a green and yellow yard mower. REAL JD's (ahem) don't have vertical shaft engines, they have at least a Kohler Thumper horizontal shaft in them and a front PTO. Just sayin! :p Depending how long it's sat and exactly who's engine that is, might need some carb work or possibly a diaphragm fuel pump, pretty easy stuff. Shave the head a little for a compression bump and get an offset flywheel key you can juice some more torque from it.

Good find on the trans, I recall a while back someone found a valve body restrictor that caused a shift flare as miles piled up, I think for 2nd gear. I should probably get the tune up kit for my own car at some point, but I just got all fresh fluid in it....SIGH!
What are you running for fluid btw? I've been liking Redline ATF but clearly am not pushing power just looking for heat resistance and consistent viscosity.
 

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Discussion Starter · #625 · (Edited)
First let me correct you, that's not a JD that's just a green and yellow yard mower. REAL JD's (ahem) don't have vertical shaft engines, they have at least a Kohler Thumper horizontal shaft in them and a front PTO. Just sayin! :p Depending how long it's sat and exactly who's engine that is, might need some carb work or possibly a diaphragm fuel pump, pretty easy stuff. Shave the head a little for a compression bump and get an offset flywheel key you can juice some more torque from it.

Good find on the trans, I recall a while back someone found a valve body restrictor that caused a shift flare as miles piled up, I think for 2nd gear. I should probably get the tune up kit for my own car at some point, but I just got all fresh fluid in it....SIGH!
What are you running for fluid btw? I've been liking Redline ATF but clearly am not pushing power just looking for heat resistance and consistent viscosity.
Real or fake it'll mow my lawn lol. The guy I bought it from had the head gasket replaced by a buddy that accidentally swapped the intake and exhaust push rods. Apparently it still ran but "was off". Then the guy tried to do a valve adjustment (and for some reason didn't swap the rods) and now the engine fights to turn past the compression stroke. It makes me think either the exhaust valve is making contact with the piston or not opening at all. I can slowly turn the crank past that point which makes me think it's the latter. Regardless if the head is damaged it's cheap to replace or even an entire engine is around 500. I picked up this mower for 300 and am throwing a new $13 head gasket kit at it while I swap the push rods and adjust the valves :LOL: I'm not worried either way.

Yeah there's a fix for the 2-3 shift flare that adds a second equal size port in the valve body separator plate. It essentially allows twice the fluid to be applied right away to the overdrive clutches. The same thing can be done to the 2nd brake that has a similar size restrictor. The 2nd brake is applied in 2nd and 4th, both of which slipped, which makes me believe the 2nd brake was the root of all issues. The bump in pressure made a huge difference and I'll be going back in to enlarge the 2nd brake restrictor.

I'm using some bulk multi vehicle atf from the dealership I was at so nothing special. Dex 6 is great fluid to run in these if you don't want to use SP3. If my Amsoil rep pulls through I'll be running 50% of their type F racing atf fluid and the other 50% of their signature series atf. He has clients making over 3000hp using that combo.
 

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Discussion Starter · #626 ·
Okay so I was backwards regarding the spring rate of the pressure valves - the higher the spring rate the lower the pressure and the longer the delays. I verified this with a stronger spring (rather than a stretched stock spring). I also found that by shortening the stock spring it decreases the time it takes to build pressure dramatically (faster and more aggressive shifts with less slipping). That coupled with enlarging certain restrictors in the valve body separator plate unlock the potential of the auto.


I attended one of the largest track events in MN this last weekend. The front lip didn't clear the trailer and I had to tow it backwards which actually towed a lot better. Unfortunately the car didn't perform well. It was high 80s/low 90s and sunny and the car had trouble staying cool. I dropped timing and was on gate pressure but that made it not build any boost off the line and feel like a dog the whole pass. After reverting the timing to my previous tune and raising the boost I took it on a quick street drive to see if it had fixed the laziness... it definitely had. So much so that it broke the trans during the 3 to 4 shift :rolleyes: I lost 3rd and 4th and had to limp it back to the race track a few miles away in 2nd gear. Since 3rd and 4th both use the overdrive clutches I assumed it was the same issue of the overdrive carrier breaking at the splines. I decided to drive 5hrs round trip to grab some extra trans parts and fix it at the track and potentially run again the same day. I pulled the side cover and found that not only did it break the overdrive carrier... but it also snapped the input shaft! There was no possible way to fix it. Not a fun way to end an expensive track weekend!





I replaced everything I could access through the side cover and all that's left is replacing the input shaft. The trans is ready to come out to be fixed and reinstalled by the end of the weekend. I'll be lowering shift pressures quite a bit now that I know it has enough torque to break the input shaft :oops:
 

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Wow! I wonder if there are other trans option available. Can a TH400 fit? lol
 

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Okay so I was backwards regarding the spring rate of the pressure valves - the higher the spring rate the lower the pressure and the longer the delays. I verified this with a stronger spring (rather than a stretched stock spring). I also found that by shortening the stock spring it decreases the time it takes to build pressure dramatically (faster and more aggressive shifts with less slipping). That coupled with enlarging certain restrictors in the valve body separator plate unlock the potential of the auto.


I attended one of the largest track events in MN this last weekend. The front lip didn't clear the trailer and I had to tow it backwards which actually towed a lot better. Unfortunately the car didn't perform well. It was high 80s/low 90s and sunny and the car had trouble staying cool. I dropped timing and was on gate pressure but that made it not build any boost off the line and feel like a dog the whole pass. After reverting the timing to my previous tune and raising the boost I took it on a quick street drive to see if it had fixed the laziness... it definitely had. So much so that it broke the trans during the 3 to 4 shift :rolleyes: I lost 3rd and 4th and had to limp it back to the race track a few miles away in 2nd gear. Since 3rd and 4th both use the overdrive clutches I assumed it was the same issue of the overdrive carrier breaking at the splines. I decided to drive 5hrs round trip to grab some extra trans parts and fix it at the track and potentially run again the same day. I pulled the side cover and found that not only did it break the overdrive carrier... but it also snapped the input shaft! There was no possible way to fix it. Not a fun way to end an expensive track weekend!





I replaced everything I could access through the side cover and all that's left is replacing the input shaft. The trans is ready to come out to be fixed and reinstalled by the end of the weekend. I'll be lowering shift pressures quite a bit now that I know it has enough torque to break the input shaft :oops:
That's impressive. Can you get the shaft heat treated or cryo treated for more hardness? It looks like if you could get parts custom made there's enough room around the shaft for a larger diameter shaft, if not maybe even a different material than steel (Titanium???)
 

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That's impressive. Can you get the shaft heat treated or cryo treated for more hardness? It looks like if you could get parts custom made there's enough room around the shaft for a larger diameter shaft, if not maybe even a different material than steel (Titanium???)
I was thinking something like 300M steel fir the shaft. Surprisingly, it seems the auto can withstand the torque output better than a manual would.
 

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I was thinking something like 300M steel fir the shaft. Surprisingly, it seems the auto can withstand the torque output better than a manual would.
Actually that's not that uncommon to find, look at clutch area and clutch pressure vs a manual, auto clutch packs can handle a lot of power. The gear sets are usually pretty chunky too. Weak links, as he's finding are usually shells, gear sets, and shafts. He might even be in the realm of flexing the case or pump housing with some of these neck snapping shifts.


OEM's get around some of this by pulling power at the time of shift application. Either by timing, boost, or in e-throttle cars just reducing throttle. If your ECM and TCM are able to communicate together you should be able to make some maps that dial back power at full throttle shifts?

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Discussion Starter · #632 ·
I replaced the input shaft and the car was back up and running. I lowered pressure at the shifts and added more delay. I believe what's happening is the overdrive clutch packs try to grab so quickly and aggressively while all that torque is at the other end of the shaft and it just snaps the smaller end right off. I broke a second input shaft last weekend and the car is back up again. I plan to engage 2 step at each shift to cut engine torque and hopefully keep the trans alive for the summer. I'm racing again this Saturday and we'll see what happens!
 

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Discussion Starter · #634 · (Edited)
I want to hear what those runs sound like man!

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I drove an hour and a half round trip to pick up the Uhaul trailer and was turned away due to expired tabs on my truck. I purchased new tabs online several months ago and was able to show that I'm still waiting on them and they didn't care. Unfortunately I wasn't willing to drive my car to the track and risk needing a tow back. I did however bring the car to "Mexico" :LOL: it did really well against a full bolt on G8 (550-600hp) and a Porsche Turbo S (~700hp). Here's the videos


 

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Discussion Starter · #638 ·
Murkrow
Time = 60-130mph ?
I'll hopefully have that number soon. I haven't done enough testing or even used my Dragy once since I bought it :LOL:

Does this mean you’ll be a power cruise this weekend?
I'm really hoping so. I'm installing a tubular rear subframe and scrambling to get it done and aligned today.
 

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Discussion Starter · #640 ·
Sorry it's been a while guys. I've been too busy with work and the days all blend together. Couple updates. I'm currently using my old Holset Hx40 turbo since it spools quicker. I made a heat shield over the front header to keep some heat away from the upper rad hose and help with cooling. I also wrapped the pre-turbo piping and downpipe to drop engine bay temps. I think ceramic coating the exhaust would add to the cooling significantly and it's on my todo list.



I installed the tubular rear subframe and was able to make it to Powercruise at Brainerd Raceway which is a weekend of racing around a 3 mile road course. Between the hot temps outside and not having the boost/adjustable timing gears dialed in, the car didn't do great.


A few weeks later and the car was gapping everyone! Unfortunately good things don't last forever. I was heading out to "Mexico" and did a test pull to the 7500 redline. It bounced off the limiter and shut off. After it cranked and wouldn't start. Turns out all 12 exhaust valves smacked the pistons pretty good (those aren't valve reliefs :whistle:). The car has been down for 3 weeks now and so has my motivation to get it running. I finally pulled the engine to tear it down. I replaced the valves and the heads are back on. The engine will be in soon and I plan to run it with the damaged pistons until it's parked for the winter.





I decided to send in my spare converter to have it restalled from 2600 to 1800 (400 lower than stock) since it doesn't lock up in 3rd. I'll gain 400rpms worth of mph in each gear without having to rev that extra 400rpms. This should extend the top of 3rd from 138mph to 148-ish mph.

Send prayers for my engine cause I still plan to dyno it this year :LOL:
 
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