The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support RTM Racing
Please Support STM Tuned

1990 Talon Tsi English Racing build 2016

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Sorry for the confusion. I was talking about the shift lever (hand) moving speed vs the dog teeth engagement, that if you hesitate when entering the gear, that would make the dog teeth grinded. And I was saying that I could be wrong but I think how quickly/smoothly you make the dog teeth engaged is more important for the dog teeth lifespan than the method how you cut torque to input shaft.

Ok yeah that sounds right to me. The last part of the shift lever movement (when you are actually entering the next gear) should be a fast movement.
 
During a drive on March 22 I noticed a lot of wacky jittery, and mostly way too high, readings on my oil pressure gauge. It was never that way before. Hopefully this was just the sensor going out, right? Hiroshi pointed out to me that it could also be a stuck (or sticking) oil pressure relief valve.

So I decided - project time. Replace that brass AEM 150 psi sensor with the stainless steel version (hopefully it's more robust), remote mount it (get it off of that hot vibration apocalypse we call an engine), and log it (I wasn't logging it before, was only using the gauge). Then at least I'll know what my oil pressure really is, and see if it is actually jittery or not.

Started driving the car again on May 3 with the new sensor remote mounted. Still no hookup to log though.

Started logging it with a very accurate logger on June 4. You can see my work timelines are pretty lengthy!

Have driven the car 18 times now since putting the new sensor on.

Decided everything is just fine, and no leaks. And pressure is not jittery at all. So I took a few pics to show the remote mount.

Basic lay-of-the-land shot:

DSC01246 Talon AEM oil pressure sensor water bottle in pic 2000 qual 90.JPG



Shot with the water bottle removed so you can see the fittings:

20230810 Talon AEM oil pressure sender remote mount (cell phone) 2000 qual 84.JPG



Shot of the Vibrant pre-made oil hose coming out of the OFH. (3 feet of -4AN stainless braided PTFE hose):

20230725_Vibrant fittings from OFH to -4 oil pressure hose 2000 qual 82.JPG
 
Fitting notes - numbering them from the OFH to the sensor:

for line and fittings from oil filter housing to remote AEM pressure sensor - crop 2000 qual 90.JPG


Fitting #2 (1/8" NPT to -4AN male): Is available in 2 materials. Steel, or aluminum. I bought steel because that's what you'd want here, for better fatigue life. Lots of vibration here acting on a part with a smallish cross-sectional area. Vibrant # 10292.

Fitting #1 (pipe thread reducer bushing, 3/8" BSPT to 1/8" NPT): This one is brass which is strong enough for this part because it's big and thick. These are hard to find but McMaster-Carr sells them as their part # 1786N244.

You could do fitting #1 and #2 with one fitting. It would be the "STM 3/8" BSPT to -4AN Fitting - DSM Oil Filter Housing" (STM-742-04-06S) which is steel. I used 2 fittings because the BSPT to NPT reducer was already there, put there by English Racing. I just decided to leave it there instead of messing with it.

Fitting #3: -4AN 45 degree angle, male to female, Vibrant # 10771

Hose #4: 3 foot pre-assembled, PTFE inner, stainless braided outer, -4AN, Vibrant # 10276

Fitting #5: another Vibrant # 10292

Fitting #6: Brass 1/8" NPT pipe coupler. It's just 1/8" pipe thread all the way through, with wrench flats on the outside. I used it to clamp the AEM pressure sensor to the aluminum bracket which is 1/8" thick. To do this, I needed to make the threads go a little deeper into it with a pipe tap. Brass is pretty easy to thread. I get the thread deep enough so the coupler is finger tight at the point where there is about a quarter turn or a little more left to bottom the end of it out against the washer on the bracket with a wrench.

All the pipe threads are sealed up with Loctite 567. This is an anerobic thread sealant, not a thread locker. It's not an RTV.

Fitting #7: Flat washer.

Here's a chart showing how aluminum and steel have a different fatigue strength characteristic (steel better):
fatigue limit or endurance limit - steel, aluminum - stress vs number of cycles- Wikipedia.png
 
Last edited:
oil pressure knee with rpm, and some rpm values added  -4  Publisher save as jpg, crop1800 qua...JPG


Here's something that I think is kind of cool. Now that I'm logging oil pressure, I can "see" the oil pressure relief valve open. The relief valve that's in the OFH.
This is something I thought should be possible and I was going to look for it. Then one day it just kind of jumped right out at me when I wasn't even looking for it. It was so obvious.

What you see is a "Knee" in the oil pressure log as engine rpm is going up. You have to look in a place where rpm is going up at a constant rate (linear). Constant acceleration. The rpm trace isn't curved, it's a straight line, tilted upward to the right. If the oil pressure trace in the same region has a bend in it, that bend is the "knee" and that is there because that is where the relief valve is starting to open.

The easiest way to get a log like this is in first gear after starting from 0 mph, not heavy on the throttle, just moderate acceleration. RPMs go up nice and linear, I guess because you aren't pushing a lot of aero drag like you would be at higher speeds.

I've seen a lot of these knees now and they always happen at about 74 psi. This agrees really well with the 1990 FSM which says on page 9-20: "Relief Valve Opening Pressure is 78 psi".
So now I know that my relief valve is working (not stuck) and that it starts to open at the design intended pressure for the 1990 type OFH.

The chart that I'm showing looks funny because I'm using a different logger (ECU+) to log oil pressure. I put that log to the same horizontal (Time) scale as my normal ECMlink log which is showing just RPM, and lined them up one over the other like shown. Points A and B are just basically the end points of the straight line part of the RPM trace.

BTW, Jafro seems to have this opening pressure figured wrong in his OFH video (March 30, 2013). I think his measurements are correct but he then forgot that you have to calculate oil pressure from the cross-sectional area of the relief piston. He didn't do that. He got force and pressure mixed up as if they are the same thing. They aren't the same thing, don't even have the same units. Pounds. Pounds per square inch.

I have what most people would call a high oil pressure engine. Some people would say too high! Anyway, that's why my relief valve starts to open at only 2020 RPM. And you can see at point B that there is about 101 psi oil pressure at 4250 rpm already. Not shown here, but around 6,000 RPM the pressure levels off at about 109 psi and doesn't seem to go any higher from there.
Using Jafro's measurements, you can calculate that the relief valve should be half-way opened at about 103 psi of oil pressure. So it's dumping a lot of oil there and maybe that's why pressure doesn't go much higher. A fully-open relief valve should happen at 132 psi. (Stock 1990 OFH)
 
Last edited:
I was a little worried about the high pressures so I asked English Racing if this was OK for my engine. I said:
My oil pressures after about 25 minutes of running, coolant temp 193 F, are:
109 psi at 6,500 rpm
108 psi at 5,400 rpm
90 psi at 3,200 rpm
34 psi at 1,100 rpm idle
Myles said "That oil pressure is fine for how your car is. Do not worry about it."

Well I wasn't surprised they said that because obviously they knew what my oil pressures were right from day one. They were the ones who said we gotta have an oil pressure gauge on it before even starting it for the first time.

But I was a little surprised that the numbers you see on Kiggly's chart "Oil Filter Losses" are the same as mine. This is Pre-Filter pressure (where our sensors are). On Kiggly's chart it's the green trace "Oil Press Pre". His chart is hard to read because the rpm's are jumping around all over and there are multiple vertical scales, but you can read it pretty clean from 3,600 to 4,600 rpm, and at very high rpm's his also sort of levels off at around 110 to 115 psi. Parts of his log have interference from his sensor being on the MIVEC feed line.

Gotta ask @DSMPT about these things and he too thinks this is OK.

So I'm just going to go with it as is. Not going to try to change it.

Note that my oil squirters and balance shafts are removed, and my oil is VR1 Synthetic, 5 quarts of 20w-50 plus 1 quart of 10w-30. ACL Race Series bearings (which have "increased crush" for better retention in their housing). Based on what I'm seeing I don't think my 1990 OFH is modified at all. It was brand new from Mitsubishi in 2015.
 
Last edited:
Warm winter night here in the boost garage. Was about 50 degrees. Fir needles all over everything outside though. Better than leaves maybe? Don't have to rake them.

I only need to add 2 or 3 gallons of ethanol free gas to my car to get my E% down to 20%. That will be my winter mix, and that's what I'm going to do tomorrow.

20231206_warm winter night in the boost garage.jpg
 
That body kit has a special place in my heart man. One of my all time favorite cars I've owned had that style body kit rear and side skirts molded onto the body, and some type of custom nardo gray w/ metal flake painted over it. I miss that car so bad and regret selling it. Glad it's spirit lives on in some form though.


Also: I have a mirage oil pressure relief spring if you want to try it. It goes with the OEM BS delete kit that the mirage's use and supposedly helps reign in oil pressure without having to do any port work.
 
Also: I have a mirage oil pressure relief spring if you want to try it. It goes with the OEM BS delete kit that the mirage's use and supposedly helps reign in oil pressure without having to do any port work.
Thanks for offering that spring. I might be interested in having one of those. Kind of reading some things about it right now. I'd probably measure it up like Jafro measured up the OFH parts in his OFH video. Probably would not put it in my car but who knows!

Is that the spring that ExtremePSI sells as MD015988 ?
I thought for a minute it might come from the same OFH used by the 1991 Galant non-Turbo which is one Jafro measured. But I guess not, because everybody in that thread FP green installation says it comes from a 1.8 liter. The one that is the same as the 1991 Galant 2 liter non-turbo is the Mirage 1.6 from what I can tell on a Mitsu dealer page.
So it might be interesting to measure it up.
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top