army_greywolf

iTrader: (2)

I rarely post on here anymore, so forgive me if you don't know who I am. I won't regale you with my experience or swing my nuts.

The point of this post was to answer a specific question. Can a bad tune ruin a turbocharger?

A customer posed this question to me without me being able to give a direct answer off the cuff. The truth is, yes a tune can wreck a turbocharger, the how is a little more complicated so if your not up on your thermal dynamics and turbo specing (housings, efficiency, etc) then ignore the bulk of this statement, since I don't have the time to explain it and I'm sure there are better sources than me for this information.

ANSWER: Yes a tune can destroy an otherwise perfect turbocharger. Here is how. The first and most common answer is surge and flutter. Compressor surge has three causes, two are common the third is tune related. The first two is improper turbo sizing and improper wastegate/bov settings (usually wrong springs entirely). The third is thermal swing (running a car from rich to lean and back in adjacent VE/MAF cells) This several hundred degree EGT change over an extremely short period of time (milliseconds) creates a standing wave effect in which the compressor is suddenly increasing in RPM, driven by hotter, faster exhaust from lean condition, then swinging to rich losing the momentum and simply falling on it's face...a flutter condition. It get's bad when you have alot of piping giving the turbo alot of cubes to compress and actually surge. It's very possible what you believe is BOV flutter is actually surge on a smaller turbo.

Ahh but most turbos are pretty tough and don't really have these problems especially in smaller engines like an LSJ. True, but there are side effects to undetectable flutter and surge from a bad tune. The first is blowing an oil seal. Carbon deposits cause this from running rich too. Journal bearing turbos are especially likely to blow an oil seal on a bad tune because they can't tolerate sudden thermal changes as well as a ball bearing turbo. Case in point customer car has a bad oil seal, has been running a terrible tune by James for a year and the car is very low miles.

Mistakes I discovered the tuner should have pointed out.

1. Baro sensor was in the vacuum stream tapped to manifold. Log files and codes should have made this apparent.

2. Wastegate not set mechanically for tapered boost.

3. Dirty MAF

4. 5V Bus on PCM not 5V, Sensor skew and so forth. PCM was bad.

Mistakes I discovered the tuner had tried to cover up.

1. Disabled EVAP, misfire and correlation codes (17 codes in all)

2. Set the timing table too high in the mids and lows (He quite clearly upped the whole table which you cannot do)

3. MAF is not tuned correctly, nor is the takeover low enough.

4. VE tune is laughable at best, so bad in fact the car has both fuel trim bank 1 lean and rich codes at the same time. If you've never done a turbo car, your best bet is to take a stock table, find your turbo spec sheet and look at the cfm rate on boost, you want to enhance the VE tables in these areas on a similar curve but MIND YOUR WASTEGATE, you need cylinder air falloff as you get close to your desired maximum boost.

5. Running a rich idle to hide rpm hunting.

6. Disabling Adaptive Spark Control

7. Setting the torque management to OFF and maxing all the tables on a customer car who drives said car in the winter. This can get a guy KILLED. As a tuner I have never disabled TM on a street car, I will not tune a car with disabled TM for this reason. All it takes is once.

8. Overan stock clutch capabilities. (Boost is 22 psi, and it surges higher, a no-no)

Anyways...it's a good answer, yes a tune can wreck a turbo, as well as the engine, hell it can take your damn life if you don't know what the tuner actually did. Think twice before doing a remote tune from someone with bad feedback. Moreover, if you don't like the tune for whatever reason, have your tuner redo it until you do, after all it is YOUR car.

And yes...it was a James tune. Tune file available upon request.

Sox-Fan

iTrader: (7)

That's horrifying. That goes past damaging a vehicle to placing someone at risk of seriously injuring or killing themself or someone else or both.

ThexGovenor

iTrader: (2)

09CobaltSS1

oy.. yet another horror story. Idk how he's even properly dialing in the VE table (or even wot maf area's for that matter) to begin with considering most of the time he tunes lsj's without a wideband signal. He's unfortunately not the only lsj "tuner" out there actively tuning who foolishly learned his tuning methods. I'd be very curious to see this file though.

army_greywolf

iTrader: (2)

I will post a before and after log tonight.

LNFTX

Can someone explain what disabling the T.M. does

Iam Broke

iTrader: (10)

Man, more fallout. Sorry he killed another one.

army_greywolf

iTrader: (2)

I don't think he killed it I mean I can rebuild the turbo, it still spools so were not talking shaft end play problems or anything like that I think it just cooked those two tiny little rings and the oring.

I am however have a bitch of a time with the VE map...anyone have a file I can compare for 80s and turbo? I am thinking part of my problem is a lazy o2 sensor (probably as a result of oil seal). I have an idle and cruise cell perfection but I just can't get it to richen up under boost...I am at a loss.

Wert842

iTrader: (3)

Ah boy. That last statement is probably going to get this locked. :/

Sent from my Samsung Galaxy S4 using CobaltSS

Cobalt08LS

iTrader: (15)

Ibl

army_greywolf

iTrader: (2)

No actually I want nothing more than to see this through to a cooperative tune. I figure the way things are going, there is a certain responsibility on my part to show how things can go bad, and then the process by which it is repaired and made right. I haven't taken an extra cent except for the credits and the tune I am doing. We have to setup the BOV and wastegate because this was not done initially.

I'd ask moderators not lock this threat, this is why I didn't title it offensively. Be damned who tuned it, I am fixing it. I want to show how you fix a car that ran for an extensive time on a bad tune but still has a good motor. Pictures, logs and more will follow.

army_greywolf

iTrader: (2)

army_greywolf

iTrader: (2)

Tomorrow, we address the wastegate issue since that will drastically affect VE, I've got it over 2000 and it still wants more fuel in some cells and I'm not comfortable with that.

Cobalt08LS

iTrader: (15)

damn! wish someone could fix my tune.! im in a huge ******* hole.
one guy loval was supose to retune me but hes a 1 man band and cant keep up with the work he has. and the work he plans. made me an appt and my car sat at his house for 3 weeks untouched.

i got tuned by a bunch of scumbags local who had no clue wtf they were doing.
my car surges, stalls, shift points are totally off. shifts arent even firm. pretty bad.

army_greywolf

iTrader: (2)

Send me the file, and your mods list.

Powell Race Parts

iTrader: (3)

Thanks to GreyWolf.

army_greywolf

iTrader: (2)

I've been doing this a long time, the practice of disabling functions of the car simply because your lazy or can't figure out how to make it work right in the first place is disheartening. And thanks.

nhanson

iTrader: (1)

Its funny how other tuner threads are locked pretty quick but this tuner in question always has his threads stay open. Favoritism at its finest....

riceburner

iTrader: (66)

ive been running my JR tune for a year and i am scared to death of finding out what was / was not actually done. :X

the only point you made that im not getting is the torque management part. i had all of my torqye management removed on my street car and i do not feel like my car is less safe than before. it just spins the tires easier, whats so dangerous about that? cobalts dont torque steer much.

anyway good looking out and warnig us this

jp1600

iTrader: (2)

Less important on a sc car i would assume, could be wrong though. You are comparing 250tq to 350ish

army_greywolf

iTrader: (2)

Whom are you referring to?

Torque Management is more import in 4 seasons driving. There are two separate systems, the brake management (stabilitrak and abs) and torque management known on diesel trucks and tractors as % slip. On a P12 pcm there is no surefire way to actually manage slip. The car is after all calculating torque which as far as rain, snow and ice are concerned can be higher or lower than desired. Having it OFF for snow and ice conditions is bad practice. Obviously you want to make sure the car cannot slip right through a low gear (on a fwd car it would mean severe understeer or overcorrection because most people will steer harder and jam the brakes as a gut check reaction)

nhanson

iTrader: (1)

Some info that isnt posted:

This wasnt a finished tune.

This customer wasnt even told that this info was posted.

A lot of this info isnt even true like being rich at idle, you really dont need TQ management in a LSJ, timing is safe (increased at cruising for MPGs)


Next time dont jump on a bandwagon.

Sox-Fan

iTrader: (7)

There is no customer identifiable information here. No vin, no car color. 07 lsj, turbo. Could be anyone.

nhanson

iTrader: (1)

The info i provided is on facebook.

Sox-Fan

iTrader: (7)

This isn't facebook. You're making comments on a post here.