Topic: Turbochargers

[Jeffy]

not really an answer to your question but it's not really worth the effort unless you run at least 5psi at which point you will need some sort of fuel management to compensate for the extra air.

there's some loss when you spin a turbo or a supercharger, so if you run low boost the difference in gain is less significant - imo not sure if it's worth it in that case.

I was wondering since it was said that Air Sierra was running only 6psi with no FMS.

[sharpxmen]

I was wondering since it was said that Air Sierra was running only 6psi with no FMS.

i don't know how he managed that, it's a mystery for me. but again, depends how fussy you are and how you drive most of the time - your engine will still run, closed loop you'll be most likely fine since even using larger injectors if you stay below 0 psi relative pressure your PCM will compensate, going in boost and open loop for that matter since you're using a stock map anything in boost will most likely be open loop, and if it isn't then you're way lean - that is a different story - how close to running the correct AFR it's hard to tell without a way to log and a wideband, anything else is guess work.

so just guessing here, if you tune it so you have enough gas for 6psi of boost you'll be safe for anything in between but too rich. If you're in closed loop and at 4psi of boost for example your AFR will be too lean for the resulting compression ration, chamber temps will go up and the side-effects associated to that.

i had that issue with mine (i was smoking black or get pinging when not in open loop) but in my case the s/c boost comes in and is pretty high at all ranges whereas with the turbo is more at the higher rpm - maybe that's the difference and you learn how to drive it to keep it in the correct operating range, not sure.

i would like to see a wideband o2 AFR, TPS, RPM and MAP log session for his setup - that way would be easier to understand how it actually works, w/o that it's pretty much guessing (his narrowband O2 output means very little).

[l3uckeyefan]

from my experience, with the bigger injecters your gonna run really rich. I would HIGHLY reccomend the FIC or split second. and for only 6lbs of boost #24 injectors are way to big.

[sharpxmen]

Well, stock on a TJ are 23.2 PSI.

if you just want the same AFR in open loop it comes down this way
stock injectors are 23.2lb/hr at 49psi TJ fuel pressure - this is when operating as normally aspirated at 14.7psi sea level absolute atmospheric pressure

for 6 psi of boost = 20.7psi absolute pressure => 40.82% increase in air quantity (assuming that there is no extra loss in your intake system) so that makes it for a required 32.67lb/hr at 49 psi fuel injector

resulting injector flow for 43.5 psi (3 bar) at which most injectors are rated would be 30.78lb/hr (EDIT: this is only relevant if the FPR has a vac/boost port, not applicable on stock TJ fuel rail - see the note on the bottom)

but you want to be richer for a turbo or s/charged applications, so 32 or even 33lb/hr would be ok

24lb/hr at 43.5psi means about 25.5lb/hr at the TJ fuel pressure of 49psi - this would be too lean for the amount of air at 6psi of boost.

not exactly 100% accurate but is pretty close approximation.

EDIT: just remember that the TJ does not have the vac port on the FPR since that is located in the fuel tank - what that means is that the fuel pressure will not increase with the amount of boost pressure so at 6psi boost the pressure differential between the fuel rail and the intake would be 43psi (the fuel pressure in the injectors will have to overcome the air pressure in the intake), so the injector required for the same AFR would be 33lb/hr at 43.5psi and needs to be higher if you need to lower the AFR (increase the amount of fuel).

[st.chevrolet]

I just finished reading your entire thread after printing it....about to read it again with highlighter. Do you still have the drawing on the bracket? Also, I saw you were a fan of the pdf book on e-bay for a basic guideline, do you still have that as well?

TIA

What year is your Jeep and do you have AC? The e-bay pdf got me interested in turbo charging my YJ and it gives some basic info on how to do it. That being said, once I had a real good look at it I realized I could build a lot better set up. I did try his tuning methods but could not get my engine to run like it should from start up, idle and all the way through the entire rpm range. Its all in my thread on the different methods I tried that did not work very well. Buy the Spit Second PSC-1-002 don't waste your time with anything else. I would also buy an AFPR, Sharpxmen is building some nice AFPR, check with him. I will help you out anyway I can with your build, and Sharpxmen is well versed in forced induction, especially with the technical stuff.

[Jeffy]

24lb/hr at 43.5psi means about 25.5lb/hr at the TJ fuel pressure of 49psi - this would be too lean for the amount of air at 6psi of boost.

not exactly 100% accurate but is pretty close approximation.

Yeah, I figured it would be too lean not rich.  With the 32-3's, what happens when you're not on boost though?  Wouldn't you run the risk of being too rich?  This is where the FMS would be crucial?

[sharpxmen]

Yeah, I figured it would be too lean not rich.  What happens when you're not on boost though?  Wouldn't you run the risk of being too rich?

usually if you're not in boost you're in closed loop so the O2 feedback should take care of that - it could throw a code as in a unusually large correction factor had to be applied (EDIT: in most cases resetting the computer would make it re-learn the fuel trims and take care of the closed loop AFR)

[Jeffy]

usually if you're not in boost you're in closed loop so the O2 feedback should take care of that - it could throw a code as in a unusually large correction factor had to be applied (EDIT: in most cases resetting the computer would make it re-learn the fuel trims and take care of the closed loop AFR)

Ok, that's right.  Forgot about the closed loop situation.

[chrisjsmith4]

Hey guys, Chris here. I followed air sierra's build almost to a T. the only thing I don't have is an intercooler which will come soon. I took my jeep to a mechanic for a po135 code and couldn't figure out what was going on. I also had him check on an issue that I was having where the jeep when I first give it throttle it hesitates and then catches up to itself. So what he found....... key on engine off my map reads 4 volts. don't know why. Also, i'm running lean when pretty much any throttle is given. I to have the injectors that air sierra used. Please look at my build on http://www.reno4x4.com/forum/showthread.php/38135-Turbocharged-2.4L-for-me-TOO!!!!
I have put it in this so called "Learn Mode" several times. When it does it runs rough for a while and after a few days it smooths out. It does the same thing if you take off the battery for about 30 minutes.

I'm still having issues with the po135 code. It is a heater circuit malfunction code. His scanner said everything is working fine with the o2 sensors. Said that it is because of the aftermarket O2. So I bought one from Jeep and it was like 105 bucks. code came back up right after I put it in. Pissed off. Any advice on this would be great too.

Just so everyone knows this started out as a budget project and for parts that I accumulated i'm only into it about 800 not including any of the extra i've put in for diag. I'm trying to keep it as cheep as possible cause i'm limited on budget. I just want it to run good. I was under the understanding that this was a simple thing. Apparently not.

I will get dyno numbers for you guys but i want to make sure everything is good first. So do all of the piggy back systems need a program and need to be adjusted manually? I don't know anything about tuning.

[sharpxmen]

Hey guys, Chris here. I followed air sierra's build almost to a T. the only thing I don't have is an intercooler which will come soon. I took my jeep to a mechanic for a po135 code and couldn't figure out what was going on. I also had him check on an issue that I was having where the jeep when I first give it throttle it hesitates and then catches up to itself. So what he found....... key on engine off my map reads 4 volts. don't know why. Also, i'm running lean when pretty much any throttle is given. I to have the injectors that air sierra used. Please look at my build on http://www.reno4x4.com/forum/showthread.php/38135-Turbocharged-2.4L-for-me-TOO!!!!
I have put it in this so called "Learn Mode" several times. When it does it runs rough for a while and after a few days it smooths out. It does the same thing if you take off the battery for about 30 minutes.

I'm still having issues with the po135 code. It is a heater circuit malfunction code. His scanner said everything is working fine with the o2 sensors. Said that it is because of the aftermarket O2. So I bought one from Jeep and it was like 105 bucks. code came back up right after I put it in. Pissed off. Any advice on this would be great too.

Just so everyone knows this started out as a budget project and for parts that I accumulated i'm only into it about 800 not including any of the extra i've put in for diag. I'm trying to keep it as cheep as possible cause i'm limited on budget. I just want it to run good. I was under the understanding that this was a simple thing. Apparently not.

I will get dyno numbers for you guys but i want to make sure everything is good first. So do all of the piggy back systems need a program and need to be adjusted manually? I don't know anything about tuning.

i didn't read your build thread yet, i'll do when i get around to it. You mentioned an aftermarket O2 - which one is it and is it a wideband? can you log the mixture readings? I'll have a look at your thread and give you my 2 cents on it.

oh, welcome to the site

EDIT: too long of a thread - let's do it differently. Please summarize the mods - more specifically the following
- boost level
- approximately what rpm do you start to see boost (like 1psi) and at what rpm do you see full boost
- injector size
- aftermarket O2 (what kind, wideband or narrowband, logging and if yes provide a log sample)
- 1 bar MAP should read about 4.65 to 4.75v with the key on from what i remember but you might want to double check.
- any mods other than the injectors for fuel management?
- how many miles on the engine since you installed the turbo?

and we'll take it from there.

Jeffy (the site admin/owner) might split this into your own thread, just a heads up - no big deal, he keeps things organized that way.

EDIT2: or moving it here in the turbo thread

[Jeffy]

Merged the "Re: Throttle body position. Before or after charger? " with the turbo Thread so it doesn't get lost.

[chrisjsmith4]

The boost level is 6psi max, it starts to build boost almost instantly and its at full boost around 2500 i would say. depends on the amount of throttle i give it. The aftermarket 02 I bought was a bosch direct replacement narrowband 02. I don't have log readings.
The injector size is 27#
Yes that is what the Map is reading. Does it just read that to begin with then go from there. I wish I was there when the mechanic was going thru all this. I like to learn things that way.
There are no other mods.
I have only had the turbo on for about a month and a half. maybe 1800 miles.

thanks for your help guys.

[sharpxmen]

The boost level is 6psi max, it starts to build boost almost instantly and its at full boost around 2500 i would say. depends on the amount of throttle i give it. The aftermarket 02 I bought was a bosch direct replacement narrowband 02. I don't have log readings.
The injector size is 27#
Yes that is what the Map is reading. Does it just read that to begin with then go from there. I wish I was there when the mechanic was going thru all this. I like to learn things that way.
There are no other mods.
I have only had the turbo on for about a month and a half. maybe 1800 miles.

thanks for your help guys.

i need to know the pressure the injectors are rated at or the P/N of the injector.

first glance if you make 6psi at 2500 rpm i would say it's too early (too low rpm) to get away without a 2 bar map. your  MAP would read all the range from 0psi boost to 6psi boost as the same pressure as it's limited to 1 bar absolute (which is basically 0 psi boost) so there is no way to adjust for the extra air.

before we get into actual numbers (that's once i get your injector rating) think of it this way - if let's assume that you sized your injectors properly and  you have the right amount of fuel for 6psi of boost to be at 12 AFR at 2500 rpm with your throttle fully open then when you are about 1/2 throttle (just an example, not saying that's exactly it) let's assume you have 0 psi boost - that means you're getting the same amount of fuel potentially (i'll explain why potentially later) for 40% less air (14.7 absolute pressure at sea level means 0psi of boost, 20.7 abs pressure is for 6psi of boost) - that means that roughly your AFR in that case is 40% richer so that makes it about 8.5 air fuel ratio - that is way too much fuel - in that scenario the PCM (the efi computer) will try to adjust the AFR based on the O2 feedback, however I don't think the trims would work for that much range so that might be one of the issues (that's what i meant by potentially earlier since in closed loop your AFR would be corrected by the O2 feedback).

there is also the rest of the range where you are at WOT (between idle and 2500rpm) where you don't make 6psi of boost, so in that case you're in open loop and the O2 feedback does not count so you'd be getting the rich condition all the way thru (this is an even worst case scenario).

once i get your injector size at the rated pressure we can run some actual numbers.

let me know if this makes sense or if you have any questions for all the above.

[Air Sierra]

Wow did not know this thread is 18 pages long!!!!!!!!!!!!

[Jeffy]

Wow did not know this thread is 18 pages long!!!!!!!!!!!!

It was 11 but two threads got combined.  You've been away too long.