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 JNZ Tuning
Please Support ExtremePSI

1G Evo 3 16g 27psi?

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.

lil corb

15+ Year Contributor
758
7
Sep 7, 2005
Woodbridge, Virginia
I self tuned to 27psi with no knock with 14* peak timing with 11.1 a/f ratio on 93 and man does it pull hard. Newborn then came and I could not finish the tune. Fast forward to present day and I am wondering, knowing the fact that 27psi is just close to the outside of the efficiency range on evo 3, should I lower boost to about 22-25 (and deal with creep) and raise more timing or should I stay with psi and raise timing until knock? Mod list is in profile but important ones are built motor, 255hp fp walbro, fic 1150cc, evo 8 Maf and link

Reason I chose to tune to 27psi is because no matter what psi I set it for (22-25) it creeped to 27psi even with map o2 dump and ported turbo inlet and wastegate hole ported.

Thanks
 
Last edited:
To find your true answer you need dyno time or passes at the track. Its hard to quantify "man does it pull hard" on a power, et, or trap speed scale.

In that case as long as there is no knock and I'm still in efficiency map then I should just up the timing and tune from there?

Thanks

Any other ideas?
 
If you're still gaining lb/min by increasing boost and your IAT's haven't gone through the roof, you should be fine at 27psi. By continuing to increase boost after airflow has leveled off or you're gaining an insane amount of intake air temps all of a sudden, then you're only hurting the turbo, your engine, and providing a platform that is very difficult to tune. Knock will likely show up before either of these happen.
 
In general riding the knock sensor is an "ok" way to tune a timing curve on a small turbo car with pump gas. You won't over time it that way most of the time. However I can't really tell you at what point you are exceeding turbine back pressure or other variables like others have posted to maximize total power output. You need a dyno or better yet some time charting MPH at the track to figure that out. Sorry, there is no other way to see how well the combo will work in the real world other than running it in the real world.
 
granted im on e85 but on my 16g I've found it pretty pointless past 25psi. I've ran it at 27psi and airflow was not changing, even ECMLink's power/torque estimates were not moving up much. I've ran 11.6@112 (with piping blowing apart in 4th before the finish) on it at 25psi so far, so I haven't had a reason to turn it up anymore as I think I'm getting most all of its potential as it is.
 
However I can't really tell you at what point you are exceeding turbine back pressure or other variables like others have posted to maximize total power output.
Something else I didn't really consider. Once the turbine backpressure level is exceeded, thrust loads go up drastically when the turbine wheel is continually trying to "push" the exhaust flow out of the housing.

A few years ago I had a customer running a TD05H 20G who wanted it to be direct-fit using the stock 1G oil lines, so I set it up with the stock thrust hardware so oiling would be the same as stock. It lived over a year with zero in/out play at 22psi....then the customer cranked the boost up to 28psi, and within 1500 miles the turbo had enough in/out play to let the compressor wheel hit the housing. In his example, just 6psi made one hell of a difference in turbo reliability. Of course this could've been altered with a different oil source and/or thrust hardware, but it did prove just how much the thrust loads go up when a turbo is pushed.
 
Ive ran higher with two different cars on a well ported E3 turbine housing and it showed positive results at the track. These little guys like a bit of back pressure to keep airflow up. But as Justin said to high of backpressure will reduce so much.

Justin think the 20g dying had anything to do with the crappy 1g oil feed line? Ive always ran -4 braided feed and my turbos hold pretty well. I did have one car that ran the stock 1G line and that turbo lived a short life at 23-24lbs. Had both 1g stock feed and return lines.
 
Something else I didn't really consider. Once the turbine backpressure level is exceeded, thrust loads go up drastically when the turbine wheel is continually trying to "push" the exhaust flow out of the housing.

A few years ago I had a customer running a TD05H 20G who wanted it to be direct-fit using the stock 1G oil lines, so I set it up with the stock thrust hardware so oiling would be the same as stock. It lived over a year with zero in/out play at 22psi....then the customer cranked the boost up to 28psi, and within 1500 miles the turbo had enough in/out play to let the compressor wheel hit the housing. In his example, just 6psi made one hell of a difference in turbo reliability. Of course this could've been altered with a different oil source and/or thrust hardware, but it did prove just how much the thrust loads go up when a turbo is pushed.
This is my worry, I'm shooting for my 11.5 on my 16g friday at its 25psi, which granted I know isnt insane - but afterwards I'm dropping it down to 20psi again. I ran 11.9@116mph on 20psi, more than quick enough for my car on the street and I'd much rather have my 16g last than kill it by stressing it just for my occasional on-ramp hooning.
Right now I'm seeing peak airflow around 41lbs which I'm more than happy with from my 16g.
 
Justin think the 20g dying had anything to do with the crappy 1g oil feed line? Ive always ran -4 braided feed and my turbos hold pretty well. I did have one car that ran the stock 1G line and that turbo lived a short life at 23-24lbs. Had both 1g stock feed and return lines.
That can't be proven, really...aside from the journal bearings themselves not really showing any sign of oil deprivation upon disassembly. In most cases the journal bearings are going to show a lack of oil long before the thrust parts do simply because the thrust system is not under load at all times like the journal bearings are....but like I said I never suggested anything different to the customer because as far as I knew the turbo was being used at a lower boost level. Had I known it was going to eventually be pushed I would have built it differently and recommended a different oil source.

I've seen some pretty remarkable things done with the stock 1G feed line....Curt Brown's old 1G ended up with a best of 10.33 and 134mph using an Evo III 16G which was fed from the head with a stock 1G feed line. Of course this isn't ideal for everyone because all engines and setups are different having different pressures, using different oils, and if the head's been shaved at all without cutting the oil port it can alter the available oil volume at the head significantly (hence many folks moving to the filter housing with a restrictor to even the playing field a bit)...but I'm just saying it's been done. :D

You must be logged in to view this image or video.
 
My setup found a 23psi spike settling to 19-20 at redline, 16º timing to be perfect. No knock on 91 crappy utah gas... we have 100 oct at $9.99 a gal... yeah right...

Thing peels layers of tire back at a furious pace. Roughly a set of tires a year as a dd, rotating every couple months, falken z rated street tires.

I'd choose less boost with more timing over pushing the turbo to its failing point. But as previously stated, a track or dyno day will be the only thing to determine that.
 
If it helps any, when I had the car tuned, it made the same power at 28psi as it did at 30. So it was turned back down to 28.
Depending on the rest of your setup, it does seem that these peak out at around 25-28psi.

I suck at driving, so my best time to date is an 11.7. But highest MPH with an 11.9@117mph.

Haven't been back in the 11's since... due to clutch issues. :/
 
Thanks everyone for input. Going to lower boost to 23 and see how much lb I'm flowing then go from there. My biggest opponent is intake temps right now so I need to go cold air ducting.
 
Steal this idea :)

You can make it out of something a little sturdier than I did, but then again i have no issues with what I used. Its an absolute pain in the anus to uninstall and install, but, it has its rewards. I can reach into the intercooler hole in my wheel well on a 90*+ day and the filter is cool to the touch. Open the hood and feel the box and its pushing mid to upper 100 degree temps. I need to find my laser temp reader and compare temps in the bay to inside the box.

I made it out of cardboard first, tack welded it all together and then just used seam sealer inside and out.

You must be logged in to view this image or video.


You must be logged in to view this image or video.


Its now painted black, and I used vacuum line that I split down the center with a utility knife around the edges so it doesn't rattle and is "sealed".

It works!
 
I like that idea. My dd evo has so much more airflow entrances and a vented hood. It also gives me more ideas or sometimes makes me want to mod it more than dsm :/
 
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