Tuning nightmare leads to good news...

[spf_lexus]

Been trying to sort out my tune all day and was tinkering around w/ fuel and for some reason landed 2 more pounds of boost... I was pulling a peak of 7psi. I had never seen it go higher than 5psi before tweaks and all I did was adjust FMU + TPS sensor + kickdown cable and landed another 20hp (guess). The rev band is much cleaner but havent sorted out this tune!!! Input guys I need your brain power!!

Can I use a SINGLE wideband to tune or a dual O2 sensor setup? Or would I need a second?

 

[stevechumo]

Been trying to sort out my tune all day and was tinkering around w/ fuel and for some reason landed 2 more pounds of boost... I was pulling a peak of 7psi. I had never seen it go higher than 5psi before tweaks and all I did was adjust FMU + TPS sensor + kickdown cable and landed another 20hp (guess). The rev band is much cleaner but havent sorted out this tune!!! Input guys I need your brain power!!

Can I use a SINGLE wideband to tune or a dual O2 sensor setup? Or would I need a second?

Great! 2 psi on the 1UZFE equal to around 35 rwhp or 48.5 bhp. That's a lot and the feeling is very significant. That means you can cut down 0.5 second. If you keep the stock exhaust that's separated from each side, you'll need a dual sensors setup to be accurate. You can tune 1 side first and check for the other later. It just takes more time.

 

[-Nemesis-]

How's them video's coming along then? :icon16:

 

[spf_lexus]

I was told by a local tuner that I would need 2 wideband sensors or at least 1 and weld 2 bungs to do the job but he quoted 5-$600!!!!! thats flippin crazy. I got the impression that all is needed is a wideband in the ttail pipe and adjust for the cats. Am I wrong? I figure the cats will clean out a pint or 2 (dont know for sure) but this way is much more user friendly than the shop costs. Plus he's tuning off a dyno and thats not quite street duty.


Steve

+2psi felt huuuge! I can pitch my LS sideways easy as cake on freeway onramps... kinda scary w/o LSD. And +35?? thats sweet, I wonder if im crossing the 300rwhp mark. A nice little side note: I noticed my FMU didnt have its "boost only" vacuum port attached... just the vac/boost and once attached it eliminated my mid throttle problem altogether. Tapped a brass threaded fitting about 6 inches away from SC and ran to boost only. Very clean pulls from idle to redline. Keeps me wondering if this 1uz really has 200,000 on her lol



Nemesis


Havent gotten pics/vids yet as i am dealing with a stubborn bracket stud. It doesn't want to thread and need this fixed ASAP since I driver a lot everyday. 3 bolts are moving the bracket a 1/4'' under load and thats not good. I just got up today thought and managed to get it to thread a few turns... going to try and re-install and cross my fingers.

 

[cjsupra90]

Duel sensors are not needed unless you can tune one bank individual from the other or individual cylinder trim if its full sequencial and in which case, you would truely need one sensor per port and also one EGT per port. Other then that, the only benifit of duel sensors or duel ports and flip flopping from port to port to port is to see how ballanced air flow is per bank and how matched the injectors are, and even then its not that accurate cause if you have two injectors that one is 5% short on flow and another on that same bank that is 5% over, the end result that the O2 will see will pretty much be the same as if all were perfectly matched (all else being equal). If you cant change fuel or air flow on one bank vs. the other, then having duel sensors is not going to aid in tuning if the engine is making good smooth power. Now if the power is low and or not smooth, then having duels or using the flip flop method can somewhat aid in diagnostics and even then, its only going to narrow it down to one side or the other.

 

[XR8tt]

Thermocouple's on each primary pipe to check heat is close to the same also... But sheesh !! It's NOT like your making 500 h.p per litre..
Colder or shorter reach plugs help with detonation and plug life also...
Usually 1 colder per 100 or so h.p...

 

[stevechumo]

Honestly, I don't think you'll need any tuning for 7 psi. You might only need to tune the fuel. Just get the fix rising rate FMU at 12:1 and your car will run perfectly, better than most tuning. You'll need tuning only when you have an aftermarket ECU or a chip, or with bigger injectors that the timing/fuel need to be tuned. The stock ECU can't be tuned.

I'm using the wideband AEM A/F gauge and I know exactly how my car runs. It runs like it came from the factory. The only thing I concern is the timing that may or may not need to be retarded. I haven't heard any knocking so I think I'm good with the timing for now.

As a rule of thumb on most cars, 7-9 psi won't need any timing retard. That's also my experience. I've been around turbo systems and built them for several years so that's what I learned. Based on the experiences of some other people boosting this 1UZFE, they didn't even tune the timing for this boost range. On my SC400, I won't change the timing after I pass 12 psi. Even if I need to retard the timing, I'll get an ignition box either from Crane or MSD to retard the timing.

 

[spf_lexus]

Yeah im leaning towards just playing around with mine some more. The big problem was i did NOT have a boost only vacuum line for my rising rate. Once attached it seemed to quench the 1uz's thirst. I noticed that the transmission kickdown cable needs to be adjusted after SC... shift points are out of whack... just loosen/tighten a full turn or so and go test... interesting not running one at all. I put back immediately after taking my first ever pull to 7,000rpm and didnt even notice the rev limiter wasnt working.

Steve

Im running for the most part "pretty clean for 7psi" and wanted to know if I should just go out and buy a wideband. David and I talked about it and said it would be a good idea to tune once and leave it... attach to the exhaust tip and compensate for cats, and dont bother w/ buying. But could I just get my static fuel pressure close and leave at 12:1?? I dont mind running a little rich but lean is the only concern. I also have 200,000 so I dont need to freak about blowing an engine... mines been through a lot. The car pulls very strong from 3k-6k and wish it was on a revving b18 so I could keep riding till 8200!! lol. And I plan on keeping the boost at 7psi.

 

[stevechumo]

For the best that I could think, you must need a wideband A/F gauge. This will give you the insurance and peace of mind whenever you boost. On the freeway and while cruising, which is under vacuum, my A/F reads 14.7-15 and that's the ideal tuning for any car. Under full boost, it reads around 11 and sometimes down to 10, which is very good. Under light boost, it reads around 12-13. At idle, it's very lean and up to 15.5-16.5. The only different ratio that I see is between under boost and without the turbo installed. The higher number, the leaner it gets.

The ratio pressure of 12 psi to 1 psi of boost is the standard for many low FI system. I'm thinking about if I could try 12 psi of boost with slightly larger injectors (20% more) and with the FMU. I'd like to see if I can boost safely without any tuning, and pass the boost point where most people stop, which is at 9 psi for this type of setup. I hope bigger injectors and fuel pump won't get stuck with this too much pressure. I think my Walbro pump starts to decrease its effectiveness at around 160 psi, but I'm not sure. I'll need to verify that. :lew:

 

[spf_lexus]

Ok I'll look into it. Hey tell me how useless this is... i have a digital auto meter air/fuel gauge and its NARROWBAND but wanted to know if I could "gimp" off this gauge. I hear it might give some idea for boost situations but cruising/idle no chance (just what i heard). Paid $75 for it and havent wired up yet.


Also, I am still running the stock LS400 fuel pump... dont know if its being over taxed but at times you can hear sounds from it as there was none in N/A form. Should I look into a walbro? and whats involved w/ install?


So far I havent noticed it consuming a huge amount of fuel and its only when I lead foot it. I have been getting a dirty exhaust tips and that maybe be a rich mix. I would rather run rich and just know it but could i calculate the amount of psi increased per full turn on static fuel on FMU and make an estimate? How many pounds of static fuel should I shoot for in a 7psi setup... that is over stock.

 

[spf_lexus]

Ok i don't want to touch anything now.... perfectly setup for street. I dont know rich/lean but its smooth as silk until I get on it and part throttle is very stock like... Found out the kickdown was trying to drop gears in the middle of throttle. Softened and it holds just fine. Also its much more responsive, feels like a stroker under the hood than SC sometimes, very quiet. It has gear whine at idle but to anyone that doesnt know his mods it just sounds like a subtle turbine sound or AC whine, frankly I like it... reminds me that I have power and its not to be uncorked for stupid reasons!! Basically w/o an LSD its like every corner around town is perfect drift material, wish someone could sort out a swappable LSD.:wtf:

 

[RedPhoenix]

Dyno runs in the future?