[lawdude]

Originally Posted by radgator1

You didn't seriously say that did you? Unlike Terry, I can verify with 100% certainty that you have never once contributed anything helpful on this forum. Often mildly amusing, and occasioanlly pretty darm funny, but never ever even remotely helpful. Wait..., maybe you were just trying to be funny again , if so than never mind

Probably because I'm an admitted ignoramus. I don't have an engineering degree. The most automotive experience I've had is changing plugs, points, and oil many moons ago. That's about the extent of my automotive knowledge. I couldn't speak intelligently about this turbo stuff if I had to. But I enjoy being educated by those who know what they're talking about. Maybe if TT would just send in the adults to talk about their product, I could sit back and enjoy some meaningful dialogue. In the meantime I'll just enjoy you calling me a dummy and me admitting to it. Stating the obvious and avoiding the real issuses is not very helpful to those who'd really like an education, but apparently that's the best that can be done.

[Corey]

Originally Posted by lawdude

Probably because I'm an admitted ignoramus. I don't have an engineering degree. The most automotive experience I've had is changing plugs, points, and oil many moons ago. That's about the extent of my automotive knowledge. I couldn't speak intelligently about this turbo stuff if I had to. But I enjoy being educated by those who know what they're talking about. Maybe if TT would just send in the adults to talk about their product, I could sit back and enjoy some meaningful dialogue. In the meantime I'll just enjoy you calling me a dummy and me admitting to it. Stating the obvious and avoiding the real issuses is not very helpful to those who'd really like an education, but apparently that's the best that can be done.

His question was rhetorical, you would notice it everytime you quickly get on the gas if the car didn't use throttle enrichment. Anyway..

Load is only half of the equation to determine fueling. At high load and high rpm it's obviously necessary to richen a:f ratios to aid in cooling among other things. However at lower rpm, for example the 3k-5k rpm range you mention, the small turbos are more efficient, producing less heat down the intake tract and the engine is running cooler. In addition to this at part throttle where power isn't a big concern you don't need the extra fuel to ensure all the oxygen is burning. I'm sure you know this and my question is do you still feel it's necessary to richen mixtures so early on? Without knowing when and where the 335 is making boost it's hard for me to say much on the subject.

[OpenFlash]

Originally Posted by Corey

Without knowing when and where the 335 is making boost it's hard for me to say much on the subject.

They make full boost, at WOT, under 2000rpm. Even at 50% throttle, they make close to full boost an any engine speed over 3000rpm. Running leaner at partial throttle is all fine and dandy. But not when you're already running lean at WOT.

shiv

[Insider]

Originally Posted by Terry Burger

Detonation isn't usually much of an issue under part throttle due to the lower load, so I don't think you really need an overly rich AF ratio unless you're @ wot. That is just my opinion, once I get some scanning software running on this thing we'll verify it.

On the 12:1 @ 5800 rpm, it works for me. I really wasn't able to spend much time below 5000rpm under boost so someone with an M6 will need to chime in here.

I think we might have unwittingly uncovered why the PROcede cars aren't really running much quicker at the track. Most of the gain is in the lower RPM band, outside the WOT range. Great if you want to floor it without downshifting, but when you’re “going for it”, power under 5000 doesn’t seem to help.

Terry,

To reach full thottle in an auto you need to put the trans in manual mode. Then, for example, shift to 5th gear around 40mph. This will put RPM's around 1,500. You can now give the car full throttle in 5th and it won't downshift. Just don't press the kickdown button at the end of the throttle, not hard since there is resistance there before you hit it. But you are at full throttle at that resistance.

[RiXst3r]

Originally Posted by Insider

Terry,

To reach full thottle in an auto you need to put the trans in manual mode. Then, for example, shift to 5th gear around 40mph. This will put RPM's around 1,500. You can now give the car full throttle in 5th and it won't downshift. Just don't press the kickdown button at the end of the throttle, not hard since there is resistance there before you hit it. But you are at full throttle at that resistance.

I was going to say this, but I kept thinking that he should know this... he must not drive around in manual mode much... I like to paddle my way around town... and go WOT at super low RPM's all the time... love that torque...

[Terry335]

Originally Posted by lawdude

Hey Terry, I was hoping that we could have some meaningful dialogue since you are an engineer with some automotive experience. Answering a question with a question isn't helpful. If you don't know the answer, just say so. Nothing to be ashamed about. Remember what Will Rogers said.

I haven't had a chance to dissect the factory 335 tune but as far as I know all fuel injected cars have enrichment parameters for tip-in. Among other things it's a little extra transitional fuel to bridge the gap between part and full throttle.

[Terry335]

Originally Posted by shiv@vishnu

Load in almost entirely related to manifold pressure in a turbo car, not throttle angle. So yes, you can get full load at less than full throttle. Just look at your boost gauge.

Just because you're making boost doesn't mean the engine is under load. Try flooring the car in neural.

PROcede cars are running 4-8mph faster traps than stock
Clearly, any shortcomings in ETs have to do with traction, not power. And yes, most of the gains are in the low end and midrange which is not taken advantage of on the dragstrip. But it's certainly enjoyed on the street.
-shiv

I suppose it was a low blow, but my point was the car doesn't spend much time below 5000rpm at WOT.

[OpenFlash]

Originally Posted by Terry Burger

Just because you're making boost doesn't mean the engine is under load. Try flooring the car in neural.

There is really nothing more frustrating that arguing with someone who thinks they understand the subject of discussions. Based upon your last statement, I think we should a stop to this debate.

shiv

[Terry335]

Originally Posted by shiv@vishnu

There is really nothing more frustrating that arguing with someone who thinks they understand the subject of discussions. Based upon your last statement, I think we should a stop to this debate.

shiv

I thought my point was simple and clearly stated, but perhaps I missed something. I'll give it another go.

My point was that knock (what we're trying to avoid with the overly rich AF ratio) is only an issue under higher loads (the force the engine is working against).

An example:

If you were to throw the car on a water dyno and freeze it at a specific RPM/gear @ WOT, I would consider that high load.

Another:

In the context of a drag race you're under less load in 1st gear WOT @ 5000rpm than you are in 5th gear WOT @ 5000rpm.

Another:

A car that weighs less will be under less load and thus less likely to detonate than one that weighs more. This leads to the famous example of a dyno-jet tuned car running perfect on the dyno (due to the 3000# dyno-jet simulated load) and the same car going out and blowing up because the actual load is a lot higher.

Making sense?

[OpenFlash]

Load defines the amount of air that is being pumped through an engine at any given time. It can either be measured directly by a MAF or calculated by a MAP. What you are describing is essentially run duration or change in RPM with respect to time. That is acceleration rate, not engine load. If you are making full boost at WOT, the engine is under the same exact load (at any given time) regardless of the gear.

The example you are referring to has to do with the car not being able to support full load for a long period of time. Whereas the run on the dynojet might have only lasted several seconds, the run on the road lasted longer.

The reason your car doesn't make much boost in neutral is because the engine is accelerating at a rate that is too fast for the turbo to "catch up" to. With only the inertia of the engine providing resistance, there isn't much work being done. This means that there is little airflow. With little airflow, there is little exhaust flow. With little exhaust flow, there isn't much motivation for a turbocharger to build boost. If you were to put a big fat heavy flywheel in the transmission, you'd see more boost in neutral because there is now more mass to spin up.

-shiv

[skitsvilli]

Originally Posted by shiv@vishnu

Load defines the amount of air that is being pumped through an engine at any given time. It can either be measured directly by a MAF or calculated by a MAP. What you are describing is essentially run duration or change in RPM with respect to time. That is acceleration rate, not engine load. If you are making full boost at WOT, the engine is under the same exact load (at any given time) regardless of the gear.

The example you are referring to has to do with the car not being able to support full load for a long period of time. Whereas the run on the dynojet might have only lasted several seconds, the run on the road lasted longer.

The reason your car doesn't make much boost in neutral is because the engine is accelerating at a rate that is too fast for the turbo to "catch up" to. With only the inertia of the engine providing resistance, there isn't much work being done. This means that there is little airflow. With little airflow, there is little exhaust flow. With little exhaust flow, there isn't much motivation for a turbocharger to build boost. If you were to put a big fat heavy flywheel in the transmission, you'd see more boost in neutral because there is now more mass to spin up.

-shiv

Damn, Shiv you are wicked smart.

[ArmyBimmerDude]

Originally Posted by skitsvilli

Damn, Shiv you are wicked smart.

+1

Honestly, why would anyone want to debate with Shiv?

[rflow]

Originally Posted by shiv@vishnu

Load defines the amount of air that is being pumped through an engine at any given time. It can either be measured directly by a MAF or calculated by a MAP. What you are describing is essentially run duration or change in RPM with respect to time. That is acceleration rate, not engine load. If you are making full boost at WOT, the engine is under the same exact load (at any given time) regardless of the gear.

The example you are referring to has to do with the car not being able to support full load for a long period of time. Whereas the run on the dynojet might have only lasted several seconds, the run on the road lasted longer.

The reason your car doesn't make much boost in neutral is because the engine is accelerating at a rate that is too fast for the turbo to "catch up" to. With only the inertia of the engine providing resistance, there isn't much work being done. This means that there is little airflow. With little airflow, there is little exhaust flow. With little exhaust flow, there isn't much motivation for a turbocharger to build boost. If you were to put a big fat heavy flywheel in the transmission, you'd see more boost in neutral because there is now more mass to spin up.

-shiv

Shiv, you are changing your statement. You claimed earlier that under part throttle, just because you have x amount of boost the engine is under full load that statement was incorrect. In any gas engine full load occurs at maximum throttle plate opening, whether an engine is NA or FI has no bearing on that.
People always seem to forget that boost is nothing more than the restriction at that given engine rpm.

[OpenFlash]

Originally Posted by rflow

Shiv, you are changing your statement. You claimed earlier that under part throttle, just because you have x amount of boost the engine is under full load that statement was incorrect. In any gas engine full load occurs at maximum throttle plate opening, whether an engine is NA or FI has no bearing on that.
People always seem to forget that boost is nothing more than the restriction at that given engine rpm.

If your throttle is partially opened, you have close to the same pressure on either side of it. Air is funny that way. But what you have with a partially closed throttle is more of an inlet restriction which means that the turbo has to work harder to acheive the same manifold pressure. Even naturally aspirated cars see close to max manifold pressure at just 30% throttle. Most of the extra power delivered by the remaining 70% comes from fuel/timing map changes dictated by TPS. Not actual load. It's not surprising that all modern turbo cars use drive-by-wire these days. So that all these subjective nonlinearalities can be "fixed". This is how turbo cars can feel remarkably naturally aspirated these days.

Shiv

[lawdude]

Next.

How about you radgator1. I know you're just itchin' to contribute something helpful on the subject of turbo-tuning.

[Corey]

Originally Posted by rflow

Shiv, you are changing your statement. You claimed earlier that under part throttle, just because you have x amount of boost the engine is under full load that statement was incorrect. In any gas engine full load occurs at maximum throttle plate opening, whether an engine is NA or FI has no bearing on that.
People always seem to forget that boost is nothing more than the restriction at that given engine rpm.

I have no idea what you're trying to say. Boost is positive manifold pressure, in other words pressure higher than atmospheric. Load is a measure of the air consumed by the engine calculated by manifold pressure, air temperature, etc. in this situation. Throttle position is not part of the equation and a TPS can not be used to assume load in a car with forced induction for a simple reason: load does not increase linearly as the throttle plate opens. It is easy to assume at 50% throttle the engine is consuming half the air it would at 100% throttle but add a turbocharger to the equation which may not be creating any boost at 50% throttle and pushing 30psig at 100% and it's plainly obvious TPS has little bearing on measured load.

[OpenFlash]

Thanks Corey

[Josh49]

subscribed. good read..

[radgator1]

Originally Posted by lawdude

Next.

How about you radgator1. I know you're just itchin' to contribute something helpful on the subject of turbo-tuning.

No, I wouldn't pretend to know much about the subject. I do think splitsecond is a reliable company and I am impressed with the performance of the TT when I had it breifly installed for testing, since as we all know, these mods are approved for offroad use only. It sure is nice to have a unit that can be installed/uninstalled in 30 seconds and without requiring messing around with the ECU. It does also make me feel better to know that when the TT was briefly installed in my car I was only running with an extra 40-50 torque and HP rather than the 90-100 ftlbs torqe of the PROcede since as we know there is more than just heat that can lead to excess wear and tear.

I'm glad Shiv is so concerned for all of us that he has posted over 30 messages questioning the safety of the TT. You would think he would be too busy working, but then again, maybe these posts are a form of work. What better form of marketing than to strike directly at the main competitor by putting fear in the minds of their potential customers? I'm sure these posts are paying off in gold (or at least in Porsche 911-turbos).

So it seems the main concern of the TT is the lean AF ratio under boost. So far I have seen no evidence that we are seeing increased detonation, or increase knock retard. So the main question seems to be is it running so lean that is is an unsafe condidtion leading to extreme excessive heat? We have seen no evidence of increased oil temps over stock, but Shiv told us we that even though the car is producing much more heat we wont see it in increased oil temps. Apparently BMW has figured out a way to ignore the first law of thermodynamics which is some pretty spiffy engineering, I must say.

[rflow]

Originally Posted by shiv@vishnu

If your throttle is partially opened, you have close to the same pressure on either side of it. Air is funny that way. But what you have with a partially closed throttle is more of an inlet restriction which means that the turbo has to work harder to acheive the same manifold pressure. Even naturally aspirated cars see close to max manifold pressure at just 30% throttle. Most of the extra power delivered by the remaining 70% comes from fuel/timing map changes dictated by TPS. Not actual load. It's not surprising that all modern turbo cars use drive-by-wire these days. So that all these subjective nonlinearalities can be "fixed". This is how turbo cars can feel remarkably naturally aspirated these days.

Shiv

It is still not the 100% calculated load of the engine. It has nothing to do with pressure differential on the inlet. At part throttle the turbos are small enough to deliver close to full boost but that does not mean the engine is under full load. This is the same for any internal combustion engine with any-type of throttle plate. Hook up a BMW scan tool and measure the calculated load and you will see it closely follows the tps percentage.

[rflow]

Originally Posted by Corey

I have no idea what you're trying to say. Boost is positive manifold pressure, in other words pressure higher than atmospheric. Load is a measure of the air consumed by the engine calculated by manifold pressure, air temperature, etc. in this situation. Throttle position is not part of the equation and a TPS can not be used to assume load in a car with forced induction for a simple reason: load does not increase linearly as the throttle plate opens. It is easy to assume at 50% throttle the engine is consuming half the air it would at 100% throttle but add a turbocharger to the equation which may not be creating any boost at 50% throttle and pushing 30psig at 100% and it's plainly obvious TPS has little bearing on measured load.

Boost is nothing more than a measure of the engines ability to inhale and exhale it's as simple as that. (Engine is an air-pump concept) Increase the engine flow characteristics and boost will drop, ie ported heads, camshaft changes so on and so forth.

It is not completely linear to the tps but full load does not happen at 50% throttle on the 335 just because you have high manifold pressure. Hook up a scan tool and read the calculated load.

[Corey]

Originally Posted by rflow

Boost is nothing more than a measure of the engines ability to inhale and exhale it's as simple as that. (Engine is an air-pump concept) Increase the engine flow characteristics and boost will drop, ie ported heads, camshaft changes so on and so forth.

It is not completely linear to the tps but full load does not happen at 50% throttle on the 335 just because you have high manifold pressure. Hook up a scan tool and read the calculated load.

I think the term you're looking for is volumetric efficiency..