theory on the power drop after 5k

[tru-boost]

the powerloss has nothing to do withthe "flaps" both AMS and CP-E have confirmed it is due to the throttle plate closing. it closes to prevent the stock (puny) turbo from going out of its efficiency range. even though you foot is on the floor, the throttle plate is only abou 40% open !
here is a link to the tests AMS did....by the way, that was my car they used !
http://www.mazdas247.com/forum/showthread.php?t=123657477&highlight=ams

 

[LBV]

40%?

I've done my own datalogging and it's more like 75% - others have said the same thing ... atleast on theMS6.

 

[tru-boost]

i have been told there is much more intrusion on the ms3.... i really dont know why. you see the info there... thats what it says !!

 

[Silo]

It starts off at 75% but if you make a full pull through 5th you will notice how it goes dows to ~40% - that's what we saw on the dyno on the ms3! I need to log the ms6 again to check if it acts the same way.

 

[FabricatorX]

Seriously guys? Look at the flowmap for the K04. There is your answer.

 

[Silo]

You want to point out that it's running at the edge of it's efficience range? Yes, and that's why Mazda choosed to progressively shut the throttle in the higher rpm band.

 

[FabricatorX]

Ahh I see, makes sense since the results would be burning up the turbo, causing oil to coke in the lines, thus potentially sending said coked oil back into motor, causing, oh, say engine and turbo failures?

 

[driver311]

40%?

I've done my own datalogging and it's more like 75% - others have said the same thing ... atleast on theMS6.

From what I have been told by a very reputable tuner it does close to roughly 70-80 percent. Far from the 40 that others are claiming. The butterflys also do the same thing. I think just doing the butterflys is gonna help alot in the topend. i have an intake manifold in the works that will be getting dyno tested on my car soon hopefully. Just removing the flaps might not be the answer. Time will tell. Ill keep eveyone posted on our findings.

 

[LBV]

Seriously guys? Look at the flowmap for the K04. There is your answer.

Does anyone know if the same thing happens with the bigger turbos? I believe the plate still closes.

 

[fourthmeal]

My vote is the mechanical fuel pump.

 

[probeturbo]

Does anyone know if the same thing happens with the bigger turbos? I believe the plate still closes.

well i am glad that you have asked this question!!! It does fall off at the same rpm as the said k04 does. Most of the reason your power falls off is because of the throttle plate closing not matter what turbo you put on there.

But what i want to know it who is the person that has stated that he butterflies start to close at that rpm as well? This is what i think/thought was going on. This is also why i think that it might be getting a couple hundred more rpms out of the car before the throttle plates take all the power away.

WBut also is this the same guy that says that the throttle closes DOWN TO 70-80 percent? so what was it before it closed to that point? i thought our cars never see 100% throttle?

I don't disaggree with the fact that the turbo is probably falling off at the upper rpms but you can't say that that is the problem with the car not pulling past 5500. There are so many other factors that can play this part. Like, Throttle plate, intake, fuel hell we can even throw in the cams for that matter. i have taken the intake apart several times.


i have looked inside of it and it has so many chambers it ain't even funny. This maybe one good way of making power in itself. When i get to the dyno we/i will see what the intake has done to my car and see if i have gotten more power past 5500 than my last dyno. also i will have a friend that has a CPE standback and he is going to dyno before the tune and after the tune to see what he can do.

 

[driver311]

I will be doing some dyno testing here in the near future. Im just frustrated with this whole power falling at 5700rpms thing. Its stupid and I cant wait till its fixed. Short shifting a car thats already hella short geared is a pain in the ass when you are making good power. Someone just figure it out already. LOL

 

[Silo]

But also is this the same guy that says that the throttle closes DOWN TO 70-80 percent? so what was it before it closed to that point? i thought our cars never see 100% throttle?

That's a fact as long as the OBD data is correct and 85% means 85% actual throttle opening. And it also is a fact that it shuts down to 40% towards 6000 rpm, at least when measured on a dyno, 5th gear pull.

 

[Jays07MS3]

That's a fact as long as the OBD data is correct and 85% means 85% actual throttle opening. And it also is a fact that it shuts down to 40% towards 6000 rpm, at least when measured on a dyno, 5th gear pull.

Yep. Here is a log I took during my dyno run (4th gear). I've also log many other non-dyno runs that show the same thing over and over again in just about all gears.

http://www.msprotege.com/forum/showthread.php?t=123683721

The graph below shows the max throttle opening position at 78%. By 6500 RPM's its down to 27%. Around 5.5K it starts closing but at 6K it starts closing FAST. Boost falls off at the same rate. Similar to AMS results.

Also interesting is how the throttle closes off in order to build boost. At around 2K RPM, it goes WOT and the throttle shoots to 78%. Then by 2800 its down to around 35% where it slowly starts opening again til it gets to about 65% by 5K RPM. And remember this is on a MS3 so a MS6 might be different.

I'm fairly certain that the turbo itself won't be able to produce much boost after 5.5K or so but we will definitely be able to gain a lot of power throughout the band if we have throttle control.

 

[buit9110]

hey i have my latest dyno sheet and i start to lose boost at around 6400 rpms, its tuned though i'll post the dyno later.

 

[tru-boost]

why do you have a fuel cut defender AND the cp-e EMS ?? seems like you are bleeding off boost for no reason.

 

[buit9110]

i don't have it installed anymore i took it out during the cp-e ems install.

 

[Crashes]

I think when he says 80-90% he might be right, think about this guys...
when you give it half throttle in 6th gear going 70 mph, your boost gauge will hold 15 pounds fine (atleast below 5500 rpm) floor it, and your car will spike 18-22 pounds and go back down to 15 pounds...same boost your pushing normally...so even if it was 50% throttle the engine would still be seeing 15 pounds but when I look at my gage anything above 5500 rpm is around 9-11 pounds which has got to mean its ATLEAST mroe then 50% throttle...realisticly 75-80%

 

[tru-boost]

nope, not true.... the throttle blade on this thing RARELY goes 75% or more open. also just because your foot is at half throttle, does not mean thats what the car is doing. after 5500rpm the throttle drops to like 40%. thats the truth. and i dont see spikes anywhere near 22psi ! 18 is the tops i see. i have heard of people seeing spikes that high, but of all the ms3/6's ive been in (several) i have never seen it happen.

 

[Jays07MS3]

nope, not true.... the throttle blade on this thing RARELY goes 75% or more open. also just because your foot is at half throttle, does not mean thats what the car is doing. after 5500rpm the throttle drops to like 40%. thats the truth. and i dont see spikes anywhere near 22psi ! 18 is the tops i see. i have heard of people seeing spikes that high, but of all the ms3/6's ive been in (several) i have never seen it happen.

I've seen spikes up to 21 psi on many occasions and have datalogged them. But it is definitely condition dependant (outside temp, rpm, gear, etc). Lately, since the temps have been down I don't see more than 18-19 psi spikes.

And there really shouldn't be much debate about the throttle closing since there has been multiple logs posted by people showing just that.