2.5 turbo build
- Thread starter Terrrs01
- Start date
You can run a AEM Failsafe gauge (30-4900) if you want to add some safeguards. It monitors boost and air/fuel and can be set up to alert you if either goes out of your programmable ranges. I added one on my turbo build to have it input into HP Tuners. That way I can log boost and wideband afr in HP.
OP
So I’ve spent a good week or 2 messing around with it and even took it wheeling!
First thing I did was weld up those leaking V bands and connect my water lines. Now that I have everything aligned I felt comfortable welding them up. I tried copper gaskets and sealant but they just kept leaking.
My HP tuners came in and I was super excited to get some tuning done on this new 2 bar MAP sensor. A couple annoying things on writing a tune is that it will fail mid write if your OBD2 port drops below a certain voltage. It took several days to figure this out, but I have some many small things drawing power when the key is on EVEN with a new battery, I have to put a charger on it while writing.
As far as the tune goes, it’s pretty frustrating. The first thing I need to do is rescale the stock 244 map sensor reference to somewhere around 190. Long story short a out stock 1 bar map sensors reads/sends out a max of 5v reference. A 2 bar Max is 2.5. After about a 30min test drive (that went real well) I got a Low Volt Map Sensor code. The new rescaling sends out a single from anywhere of 0.050-2.5 and the computer reads that as a problem and but the keep into limp mode. I’ve got ahold of a few people to try to help. Typically in most vehicles you can just adjusted the volt reference error points directly and you would just lower the map low end volt setting to 0.01 or something like that to keep the computer happy.
However I guess our JTEC computers use the map sensor as a barometric sensor right before start up and by rescaling those I can potentially solve the problem. I spent about 3 days attempting multiple adjustments but had a wheeling trip planned this prior weekend and for now skipped backed to the 1 bar stock tune. Which honestly does really good for wheeling, but not highway driving. A highway speed I’m in boost for a long time and now it throw a map sensor HIGH code lol.
I still need to work out a radiator tank. Might use the windshield wiper as of now this is my solution lol.
Also I had to remove the fan shroud and it did over heat while wheeling several times. I ordered a 16” electrical fan to hopefully draw some heat from the radiator.
Hopefully soon I’ll be able to figure about this 2 bar map/low voltage problem.
Below are some pics/videos from this weekend. Hopefully the sounds quality doesn’t get effective and you can hear the baby turbo sing!
First thing I did was weld up those leaking V bands and connect my water lines. Now that I have everything aligned I felt comfortable welding them up. I tried copper gaskets and sealant but they just kept leaking.
My HP tuners came in and I was super excited to get some tuning done on this new 2 bar MAP sensor. A couple annoying things on writing a tune is that it will fail mid write if your OBD2 port drops below a certain voltage. It took several days to figure this out, but I have some many small things drawing power when the key is on EVEN with a new battery, I have to put a charger on it while writing.
As far as the tune goes, it’s pretty frustrating. The first thing I need to do is rescale the stock 244 map sensor reference to somewhere around 190. Long story short a out stock 1 bar map sensors reads/sends out a max of 5v reference. A 2 bar Max is 2.5. After about a 30min test drive (that went real well) I got a Low Volt Map Sensor code. The new rescaling sends out a single from anywhere of 0.050-2.5 and the computer reads that as a problem and but the keep into limp mode. I’ve got ahold of a few people to try to help. Typically in most vehicles you can just adjusted the volt reference error points directly and you would just lower the map low end volt setting to 0.01 or something like that to keep the computer happy.
However I guess our JTEC computers use the map sensor as a barometric sensor right before start up and by rescaling those I can potentially solve the problem. I spent about 3 days attempting multiple adjustments but had a wheeling trip planned this prior weekend and for now skipped backed to the 1 bar stock tune. Which honestly does really good for wheeling, but not highway driving. A highway speed I’m in boost for a long time and now it throw a map sensor HIGH code lol.
I still need to work out a radiator tank. Might use the windshield wiper as of now this is my solution lol.
Also I had to remove the fan shroud and it did over heat while wheeling several times. I ordered a 16” electrical fan to hopefully draw some heat from the radiator.
Hopefully soon I’ll be able to figure about this 2 bar map/low voltage problem.
Below are some pics/videos from this weekend. Hopefully the sounds quality doesn’t get effective and you can hear the baby turbo sing!
HP Tuners is garbage on the JTEC controllers. I was having multiple issues on the JTEC 4.0. The closed loop will cause the fueling to be very inconsistent. Also the idle is goofy when cold. Warm it it okay, but cold it hangs like crazy. When I contacted HP they wanted me to find the solutions for the problems and help them fix the issues. I am working on a stand alone unit for the TJ right now. FYI my settings were 218 on the scale multiplier for the GM 12615136 sensor. MAP WOT Count I have 105. MAP Max counts I had 255 and MAP 5v Lo Limit I had 60. No check engine lights and runs okay in open loop. I changed the Closed loop enable coolant temp to 300 degrees and disconnected the battery for 30 minutes and I get no more fuel trims. It works okay that way. It would never pass emissions and runs rich sometimes and lean others. Without the o2 feedback it is always off a bit. The stand alone company I am working with will be a bit more expensive than HP, but will have many options above what HP has to offer.
I'll be following this build as even though I have a LS swap planned, I have been curious as to how a budget turbo setup would do on the 2.5L. I have been tuning GM (mostly Gen3 LS) vehicles for 20 year and currently use HPT. I am interested to seeing what all tables HPT is pulling back for the JTEC.
OP
That’s sounds very similar to what I’m at now besides the 5v Lo limit change. I also changed a few things are to keep it in open loop but I see what your saying as to 02 feedback. Did you have to make any barometric adjustments at all?
-Also when you guys are let me know, I’d be interest in seeing what you guys offer.
OP
I took a guess in the dark on this turbo size, but I’m very happy with it. For as insufficient as my 2.5 is, it spools up very quick and for my 7lbs of boost I’m ok with the cheap turbo. Even more so this jeep see’s 80% of its time wheeling and only 20% cruising around town. If it was a daily driver I still like the idea of buying a cheap turbo specifically to “test” your size, and then if it spools where you want then spend big money on a nice turbo.
The main issue with HP is the lack of available parameters. I have SCT tuned lots of other vehicles with JTEC controllers very successfully. The SCT has more parameters relating to the adaptive feedback and closed loop fueling. Specifically a maximum MAP value for closed loop feedback. HPs lack of coverage over those parameters makes proper closed loop impossible on boosted vehicles. As for the baro correction, there is a table in the fuel or airflow tab that is a correction for altitude. I can't remember off the top of my head what it is called exactly, but bbn I just changed the entire table to 1 or 0 whatever the base value is.
If you are accustomed to HPs coverage for the LS platform you are going to be properly disappointed with the JTEC. I think that there are more tables in one tab for the LS than all of the JTEC. I can send you the base file from my 4 liter if you want it. Also keep in mind the JTEC requires the mpvi 2 so if you're like me I already have a mpvi 1 and had to go and buy a 2 just for this.
Yea, the lack of JTEC mapping support from HPT is disappointing to hear but not surprising. I also have an enhanced MVPI1 and use standalone data logging at the track so have not upgraded to the MVPI2.
I would be interested in seeing the file. You can send it to bigkid at ls2 dot com at your convivence.
I would be interested in seeing the file. You can send it to bigkid at ls2 dot com at your convivence.
how is the turbo'd angry squirrel doing? I check for updates to this regularly
ummm, not sure why people are laughing but I have a 2.5! To the OP, I am being honest and look forward to any information you share.
Don't worry it's all good.
Yep I enjoy reading his updates also since I came from the 4 angry squirrels family.
I'm totally with you on this! I contacted him the other day to see how things were going. It's just good to know I'm not the only one who's interested in the progress taking place behind the scenes.
I'm picking up on the theme of just how ANGRY your rig must be!
Maybe I can get @Terrrs01 to chime in on one of his favorites... Something about "the heavens shedding tears when he cracks into the rev limiter"...
OP
I’ve had this 4banger jeep for 15+ years. I’m use to the jokes they don’t bother. The real downside to the 2.5 is highway speed, but Offroad it’s just fine. Plenty of well built buggies use smaller 4banger with some strong gearing.
OP
Hahah it we stole some quote from some forum years ago... when I put it in 4-low angles from heaven weep........I'm picking up on the theme of just how ANGRY your rig must be!
Maybe I can get @Terrrs01 to chime in on one of his favorites... Something about "the heavens shedding tears when he cracks into the rev limiter"...
-however NOW I might change it to... Angels weep when the boost starts to creep (working title) lol
I ain't gunna say I could win a race even if it was with a 1962 VW Bug but I could accelerate to highway speeds and merge safely onto the freeway with 4.88 gears and 35" tires. Climbing Snoqualmie Pass wasn't a LOAD of fun but I could do it and most of the time I could stay at 55MPH or higher. I was @5K RPM's a lot of times and wasn't scared to push it.
Sometimes wish I'd stayed with the 4 banger.
OP
General Update: pics below
-I’ve been able to wheel it once about 3 weeks ago and had a over heating problem when going less than 2-3 miles/hour. During this trip I was also still on my stock 1 bar map tune which runs real good for wheeling but not so good at cruising speeds above 50mph.
-since that trip. I’ve put on an electric fan. Installed pipe heating fabric over my downpipe from my turbo. Then I also installed a GenRight hood louver. And finally found a small overfllor
-My general goal is to lower my coolant temp (e-fan) but even more so lower my under hood temps. That turbo really added a bunch of extra heat under the hood that is not there typically.
-As far as the 2bar map tune. I’m still unsuccessful. I’ve gone through so many tunes, and can’t really get away from this limp mode that seems to be activated. This is all on a GM2 bar map sensor of a GTP. I’m going wheeling this weekend (still on the stock 1bar) but when I return I’m going to install a 2.25bar map sensor from a dodge neon SRT4 and see how that acts.
-I’ve been able to wheel it once about 3 weeks ago and had a over heating problem when going less than 2-3 miles/hour. During this trip I was also still on my stock 1 bar map tune which runs real good for wheeling but not so good at cruising speeds above 50mph.
-since that trip. I’ve put on an electric fan. Installed pipe heating fabric over my downpipe from my turbo. Then I also installed a GenRight hood louver. And finally found a small overfllor
-My general goal is to lower my coolant temp (e-fan) but even more so lower my under hood temps. That turbo really added a bunch of extra heat under the hood that is not there typically.
-As far as the 2bar map tune. I’m still unsuccessful. I’ve gone through so many tunes, and can’t really get away from this limp mode that seems to be activated. This is all on a GM2 bar map sensor of a GTP. I’m going wheeling this weekend (still on the stock 1bar) but when I return I’m going to install a 2.25bar map sensor from a dodge neon SRT4 and see how that acts.