turbo 5.0 runs pig rich at idle, rough.

[rj95svt]

But on a boosted application your asking for trouble. Any detonation can destroy a boosted motor.

 

[millhouse]

But on a boosted application your asking for trouble. Any detonation can destroy a boosted motor.

Which is why many choose to lock the timing at a known safe total.

 

[ninety15.0]

I guess the reason i bought my tweecer was because of those small annoying driveability problems. There's also plenty of people out there who are running wild HCI or FI who have near perfect stock driveability with great fuel economy and track numbers.

Within the first 30 minutes of tweecing my car i was able to start it cold and walk away without touching the gas...and come back 10 minutes later all warmed up and idling perfectly with a nice little lope. I dont think i would ever be able to go back to HAVING to sit in the car and feather the throttle to keep it running. Sounding like a redneck at 7am out in the driveway revving his obnoxiously loud car to keep it running...no thanks man. I tune is absolutely necessary once you start messing with the MAF and injectors, nevermind FI.

 

[rj95svt]

Yes but that is not all. A safe A/F ratio N/A isn't safe in a boosted application. Most people shoot for a 11-11.5 A/F on boosted cars where N/A runs best with about 12.5-13.0.

 

[millhouse]

Yes but that is not all. A safe A/F ratio N/A isn't safe in a boosted application. Most people shoot for a 11-11.5 A/F on boosted cars where N/A runs best with about 12.5-13.0.

Correct, which is the reason to get a blow through MAF along with matching injectors.

Listen, there is no argument that there is no substitute for a proper tune, but you guys are coming off as if you need a tune or else your junk's going to explode…which is simply not true.

I myself ran a pro-m univer blow through along with 42lb injectors and had no starting issues and drivability was actually pretty good. Sure it bogged a bit (very minute) at low load areas as my timing was locked at 18-20*…but it started just fine every morning and idled without issues. Hell, even my AFR's were good…albeit overly rich under boost.

With that said, ultimately I ended up building my megasquirt setup as it was inevitable the next progression in my learning. I already knew how to mechanically do it all…and it was a logical step towards being "complete".

 

[ninety15.0]

Correct, which is the reason to get a blow through MAF along with matching injectors.

Listen, there is no argument that there is no substitute for a proper tune, but you guys are coming off as if you need a tune or else your junk's going to explode…which is simply not true.

I myself ran a pro-m univer blow through along with 42lb injectors and had no starting issues and drivability was actually pretty good. Sure it bogged a bit (very minute) at low load areas as my timing was locked at 18-20*…but it started just fine every morning and idled without issues. Hell, even my AFR's were good…albeit overly rich under boost.

With that said, ultimately I ended up building my megasquirt setup as it was inevitable the next progression in my learning. I already knew how to mechanically do it all…and it was a logical step towards being "complete".

No one said if you dont get a tune your junk is going to blow up? Are simply saying, you obviously spent a lot of money on an engine combo and FI...why not spend the extra money to make the car run right?! Obviously every single fueling perameter in the stock ECU logic was set for use with 19's. A "calibrated" MAF doesnt mean its going to make the car run like stock. The ECU is also calibrated to run 39psi fuel press...what happens when you mechanically change that. Most people dont understand the complications associated with running matched injector/MAF combos. While they may give you OK dirveability...they are far from what a properly tuned car will give you in terms of reliability, repeatability, fuel economy, and safety.

I dont want to get in some stupid pissing match, I just think you are arguing the wrong direction for the original poster. The guy needs a tune.

By the way running overly rich is pretty dangerous too! i dont consider that safe

 

[millhouse]

No one said if you dont get a tune your junk is going to blow up? Are simply saying, you obviously spent a lot of money on an engine combo and FI...why not spend the extra money to make the car run right?! Obviously every single fueling perameter in the stock ECU logic was set for use with 19's. A "calibrated" MAF doesnt mean its going to make the car run like stock. The ECU is also calibrated to run 39psi fuel press...what happens when you mechanically change that. Most people dont understand the complications associated with running matched injector/MAF combos. While they may give you OK dirveability...they are far from what a properly tuned car will give you in terms of reliability, repeatability, fuel economy, and safety.

I dont want to get in some stupid pissing match, I just think you are arguing the wrong direction for the original poster. The guy needs a tune.

By the way running overly rich is pretty dangerous too! i dont consider that safe

For the most part, I'm not arguing with you.

I will say though, tweaking the fuel pressure slightly to achieve an AFR closer to stoich during closed loop is not a big deal…and can help quite significantly if you have drivability issues.

I really don't see any issues with both reliability and safety with simply running the way I mentioned (assuming you can monitor your AFR's).

As far as running overly rich goes…at a certain point, yes…it can be dangerous. For the most part though, it's far better (and safer) to run overly rich than lean. FYI, when I had mentioned me running overly rich…I was referring to somewhere in the 11:1 range. That's not even close to what I would consider an unsafe tune.

This all relates back to the original poster however. His car should be able to idle and drive with his current setup, without a tune. There is most likely something else wrong with his car…and going out attempting to tune it could be a costly mistake.

 

[Mr. Rustypwnz]

im gonna say you have a big vaccum leak, I used to have an svo and it wouldnt even run if you had leak of any kind, these leaks arent as noticeable on n/a cars as they are on turbod cars, and yes he should be able to get on it and drive it around and idle fine with your current setup.

btw: how long have you had it runnin( sitting idleing )? id let it sit and idle for a while, even if the revs have to be at 2k, then start backing off when the temps start coming up to par.