What turbo to just extend the powerband

[8.5MS3]

boost pressure is directly related to how much air the engine can breath in at any given rpm vs how much air the turbo can move.

Assuming 100% volumetric efficiency

Air flow rate = (displacement)(rpm) / Strokes * conversion factor

MS3 - 2.3 liter @ 5800rpm

AFR = 140ci*5800* / 2*1728 = ~235 ft^3


GTI - 1.8 liter @ 5800rpm

AFR = 122ci*5800 /3456 = ~205ft^3

They do not push the same amount of air at a given rpm

To go one further:

again assuming 100% VE

boost = (max cfm of turbo/AFR)*14.7 - 14.7
MS3 - (X/235)*14.7 - 14.7 = 15.7psi..... x= 486cfm
GTI - (X/205)*14.7 - 14.7 = 15.7psi...... x=424cfm

the x values are how much cfm the turbo is required to push to achieve 15.7psi

again they are not the same. This does not account for the engine volumetric efficiency, engine design etc. which in either case will not be the same for both engines.

so 15.7psi is not always the same cfm. This further proves that the K04 is undersized for the 2.3.

and to show it is in fact still making power above 6k please see attached dyno chart and datalog. power is beginning to drop at 6100rpm, but that is due to flow limitations of the engine itself, the turbo is still pushing 18+psi at 6200 in the attached datalog

 

[MSMS3]

I will try one more time. I am sorry I was not clear.

I am not now saying nor have I ever said that a particular cfm flow is a particular psi. These are two separate components of a gas column in calculating its total mass. They must be considered both separately and together. I am talking about the combination of the two. And I am referring to the ability of the turbo to flow a pressurized air column into the hot side of the intercooler, not the exhaust flow of the engine it is connected to.

350 cfm AT 15 psi is 350 cfm AT 15 psi regardless of which engine the turbo is attached to. Or stated conversely, a 15 psi column of air flowing through a pipe of known size at 350 cfm is a 15 psi column of air flowing through that same pipe at the rate of 350 cfm, regardless of the source. I am talking about a pressurized column of air that is both flowing through a pipe of known diameter at 350 cfm and also is at two atmospheres (approximately) of pressure. In this case, the pipe is the compressor side of the turbo exiting into the "hot" side of the intercooler.

Please note that in the posts I am talking about a given flow rate at a given boost pressure. This has absolutely nothing to do with the capabilities of any particular engine or its internal effeciency. I am assuming that the engine produces an exhaust output sufficient to turn the K04 turbo to the point where it's compressor side is generating 15 pounds of boost AND flowing 350 cfm WHILE DOING SO and that the intake tubing and filter can provide the necessary air.

I hope this is clear. It is the combination of the flow rate AND the boost pressure together that produces the excessively high heat levels inside the turbo. When the turbo is driven into inefficiency the result is that heat inside the turbo soars.

The turbo is absoutely stupid, totally ignorant of what the source of the flow is. It doesn't know and doesn't care. All it "knows" is that, in the example above, it is maxed out and cannot flow more. The extra effort to push more air through the system converts the air to heat on the compressor side. And when the point of maximum resistance is met on the compressor side, more exhaust entering the turbo cannot spin the shaft any faster. That exhaust energy can no longer be converted into faster wheel movement, so the extra heat is transferred to the surrounding metal surfaces, including the shaft attaching the two wheels and exhaust temps soar.

Sorry if I was not clear before.

Now, as to the K04's 5 mm inconel shaft, the engineering report commissioned by Neuspeed indicated that temps have to be kept below 875 degrees C. which is 1607 degrees F. measured by a sensor tapped directly the turbine side housing of the turbo. If temps exceed that level, then even if the turbo is still making power at higher rpm their research concluded that the shaft will soften, start sagging and fail.

All I know is that that aftermarket company engaged in some pretty expensive and extensive research and a costly decision to suspend sales until the root cause of the failures were identified. This lead to redevelopment and modification of the software for the ECU's so that boost pressure was bled off after 5,800 rpm to keep exhaust temps down to safe limits,and the issuance of some sensible guidelines for safe operation of that particular K04.

 

[Wurf]

OK I tried this today. I wound my car up to 6200 RPM and held it there for a half hour. Then I quickly pulled over and popped the hood. I whipped out my cock and pissed on the turbo. Steam went everywhere and it was really ******* hot. The car still runs great.

I knew what MSMS3 was talking about before, but now I can say I have proof it's bad for the turbo to run it past it's efficiency range for extended periods while trying to make more power.

And on to the next episode.

 

[MSMS3]

LMFAO to extreme, Wurf!

 

[8.5MS3]

I believe we were arguing 2 different points. After re-reading your posts yes you are correct in your statements. I was arguing the point that the 5800 rpm deadline in that article is not applicable to our cars. It is at some other point in the powerband.

 

[mortimersnerd]

This thread makes me insanely happy. I haven't heard this much sheer geekery since Sport Compact Car shut down. Anyway, thanks to all, I'm really enjoying this.

 

[bf360]

http://i83.photobucket.com/albums/j299/laloosh04/gt35r/345.jpg

 

[Wurf]

Perfect example of what I was talking about. Compare where the factory motor torque peak is VS that dyno graph. Move the powerband upward to have more at higher RPM and what do you know, low speed power and response diminishes. Yes there's a lot more power up there with that setup but the character of the motor is completely different. I bet that motor goes from lazy to HOLY s*** in no time. Probably a lot of fun but I wonder how it would be to live with as a DD car.

 

[Darth Vader]

I be thinking the best answer is to make more area under the curve with this engine. "Powerbands" don't just move laterally. My focus has been to move the curve up and create more area under it. This intensifies the hilarious stock engine characteristics while adding a touch better performance at high rpm, as the falloff is held off slightly longer.

I am making a conscious decision to stay with the stock tune and stock major hard parts but, by opening up the intake and exhaust, I've shifted the curve upward from stock, without changing its basic profile. This is the easy way to at least decent, cheap, reliable DD power in this car.

So, Intake, TIP, Forge, DP and race pipe, FTW. This car's engine has more in common, feel-wise, with my old supercharged 5.0 than my neighbour's V-Dick Si.

 

[Wurf]

I be thinking the best answer is to make more area under the curve with this engine. "Powerbands" don't just move laterally. My focus has been to move the curve up and create more area under it. This intensifies the hilarious stock engine characteristics while adding a touch better performance at high rpm, as the falloff is held off slightly longer.

I am making a conscious decision to stay with the stock tune and stock major hard parts but, by opening up the intake and exhaust, I've shifted the curve upward from stock, without changing its basic profile. This is the easy way to at least decent, cheap, reliable DD power in this car.

So, Intake, TIP, Forge, DP and race pipe, FTW. This car's engine has more in common, feel-wise, with my old supercharged 5.0 than my neighbour's V-Dick Si.

Agreed +1

 

[Bravnik]

http://i83.photobucket.com/albums/j299/laloosh04/gt35r/345.jpg

That post does not mean much. Who's car, what are the mods, what tuning solution did they use etc. etc. etc.

Besides - That Dyno is of LaDouches car which everyone who knows anything about the MS3's (Including LaDouche) knows his car was pure fail and every single dyno he ever did was in question.

I can post up 10 BT dyno's and even a custom turbo setup with different fueling for the MS3 and they all drop between 5500 and 6200 rpms (depending on tuning solution).

 

[MSMS3]

I be thinking the best answer is to make more area under the curve with this engine. "Powerbands" don't just move laterally. My focus has been to move the curve up and create more area under it. This intensifies the hilarious stock engine characteristics while adding a touch better performance at high rpm, as the falloff is held off slightly longer.

I am making a conscious decision to stay with the stock tune and stock major hard parts but, by opening up the intake and exhaust, I've shifted the curve upward from stock, without changing its basic profile. This is the easy way to at least decent, cheap, reliable DD power in this car.

So, Intake, TIP, Forge, DP and race pipe, FTW. This car's engine has more in common, feel-wise, with my old supercharged 5.0 than my neighbour's V-Dick Si.

Agreed +1+ . Darth and I have very similar mods and approach the power increase with the same goals: raise the power band vertically all across the board by reducing restrictions to air flow at the intake and the exhaust at the points where the most severe bottlenecks are located and sticking with the stock tune. This approach makes sense to me. I realize others differ and respect that.

The stock tune starts closing the throttle body by around 5,800 rpm as a way of protecting the turbo from overheating. I don't know if they did this for the same reasons that caused the aftermarket K04 tuners to revise their ECU maps after the Audi-VW K04 turbo shaft failures. But it makes sense to me that they may have been concerned with the same issues. Either way, I like that built in safety. I' m content to operate the turbo within its efficiency limitations and conservatively mod for more power under the curve.

 

[mazdaspeed32007]

Agreed +1+ . Darth and I have very similar mods and approach the power increase with the same goals: raise the power band vertically all across the board by reducing restrictions to air flow at the intake and the exhaust at the points where the most severe bottlenecks are located and sticking with the stock tune. This approach makes sense to me. I realize others differ and respect that.

The stock tune starts closing the throttle body by around 5,800 rpm as a way of protecting the turbo from overheating. I don't know if they did this for the same reasons that caused the aftermarket K04 tuners to revise their ECU maps after the Audi-VW K04 turbo shaft failures. But it makes sense to me that they may have been concerned with the same issues. Either way, I like that built in safety. I' m content to operate the turbo within its efficiency limitations and conservatively mod for more power under the curve.

why not re-tune and not shift over your limit? or tune it so your power curve drops afterwards? i left mine on a stage 2 tune and shift at 5600. if i go over that by 600 rpm on accident i didnt lose anything on the long shift.

 

[MSMS3]

why not re-tune and not shift over your limit? or tune it so your power curve drops afterwards? i left mine on a stage 2 tune and shift at 5600. if i go over that by 600 rpm on accident i didnt lose anything on the long shift.

I see your point. The retune would need to have the same or better rise all across the power band I'm getting with my current mods on the stock tune without exceeding stock boost levels. I don't want to lose any of the fatness of the curve trying to get a few extra peaky hp up at the shift point. It would also need to preserve the safety features of the stock tune to help keep me from going boom if I slip into boost creep or overboost in cold weather. So, I'm thinking that for my needs a custom tune would not provide much benefit for the buck.

 

[mazdaspeed32007]

I see your point. The retune would need to have the same or better rise all across the power band I'm getting with my current mods on the stock tune without exceeding stock boost levels. I don't want to lose any of the fatness of the curve trying to get a few extra peaky hp up at the shift point. It would also need to preserve the safety features of the stock tune to help keep me from going boom if I slip into boost creep or overboost in cold weather. So, I'm thinking that for my needs a custom tune would not provide much benefit for the buck.

yea i guess so. have you seen any stage 2 dynos? if you could compare the stock tune with the stage 2 and disregard the final rpms to red line you may benefit quite a bit from the tune. as i said all you would have to do is self tune the top end to drop off for your safety. you could run it hard to 5500 and have it taper to 5800 then pretty much kill it at 5800-6000. i felt a big difference between stock tune and stage 2 tune and shift way before redline. sorry i dont have any dyno sheets to show you the difference besides my experience with the different tunes. the new 105 tune is hardly street drivable. far to aggressive for a dd imho.

 

[MSMS3]

Thanks, 32007. I'd like to see some dyno sheets on the type of tune you are suggesting.

 

[bf360]

That post does not mean much. Who's car, what are the mods, what tuning solution did they use etc. etc. etc.

Besides - That Dyno is of LaDouches car which everyone who knows anything about the MS3's (Including LaDouche) knows his car was pure fail and every single dyno he ever did was in question.

I can post up 10 BT dyno's and even a custom turbo setup with different fueling for the MS3 and they all drop between 5500 and 6200 rpms (depending on tuning solution).

haha his car was pure fail haha?
is that why he still holds the record for highest whp on the stock turbo at 327whp? right cause his car was fail

It was tuned with a stand back with a gt35r

 

[mazdaspeed32007]

haha his car was pure fail haha?
is that why he still holds the record for highest whp on the stock turbo at 327whp? right cause his car was fail

It was tuned with a stand back with a gt35r

remember he may have the highest whp but it also turned into a piece of s***. ill get 500 out of mine...it just wont run afterwards.

 

[mazdaspeed32007]

Thanks, 32007. I'd like to see some dyno sheets on the type of tune you are suggesting.

let me see what i can dig up for you.

 

[Bravnik]

haha his car was pure fail haha?
is that why he still holds the record for highest whp on the stock turbo at 327whp? right cause his car was fail

It was tuned with a stand back with a gt35r

Dude, LaDouche and his car were both fail. End of story. If you think not then you don't know jack s*** about our cars or the mazda forums (all of them).

Hell he was even banned off of MSF for his douchebag attitude and negative posts even after he gave up on his MS3 and parted out. Now he is a laughing stock on the BMW forums. Good riddance, they can have that POS.