So Boosting Our MSP's is not good..??
- Thread starter TBMSPED
- Start date
- Status
because you are adding a restriction to the wastegate "circuit", causing it to spool faster- just like you would do by upping the spring pressure in the gate. It is *possible* it will not be as bad, but it will still happen. You are taking something that spools lightning fast, making it spool faster and expecting it to stop on a dime 
.. Just like the faster you drive, the longer it takes to stop I guess .
Joe
.. Just like the faster you drive, the longer it takes to stop I guess .Joe
- :
- MP5T / 944
AutoBox said:
That is fine if you have an external wastegate. I know Tial has more than 6 different springs for my wategate. The reality is that users on this board mostly have MSP stock setups with the T-25. this wastegate is set by the factory and I think it would be difficult to just get a "10 Psi" spring for the stock wastegate.
With just swapping the spring, there is no way to know where it will open unless you take it for a drive every time you swap springs.
Might over boost and cause damage.
The Boost controller is the way to go. Just make sure it's a good piece and the lines are as short as possible.
(p5white) (friday) (p5white)
- :
- MP5T / 944
kwiktsi said:because you are adding a restriction to the wastegate "circuit", causing it to spool faster- just like you would do by upping the spring pressure in the gate. It is *possible* it will not be as bad, but it will still happen. You are taking something that spools lightning fast, making it spool faster and expecting it to stop on a dime
Joe
One other consideration might be that the wastegate can't open enough to slow the turbine at higher pressures. The gate has to open to allow ALL the exhaust by for a short time to allow the turbine to stop spooling higher then close a bit to maintain the spool. It's an very precise device, it must react quickly in millimetres changes to maintain Boost at WOT.
An external wastegate offers a much larger opening and a larger margin of error. I have never had an integrated wastegate and I realise that it is the industry standard and has been proven to be reliable but I would never own one. There are too many chances for something to fail and blow a motor.
Stock motors on stock boost...
(dark)
- :
- MP5T / 944
kwiktsi said:yeah, that's what I thought- 20 psi will cut the life of a T25 drastically
Joe
The T-25 can't make 20 Psi. If you look at the pressure map for this design you will notice that to make even 17 Psi at the A/R that you need for the 2.0 L DOHC, the turbine would have to spin at upwards of 125,000 RPM and would fail. Also the Air Charge would be somewhere to the order of 250 Deg Celcius.
I know you were generalizing, just thought you would be interested in this info. (2thumbs)
Later...Brian(nana)
DiscreetSpeed
Member
- :
- 03 MSP
by 15 psi? haha i highly doubt it.
Brian MP5T said:The T-25 can't make 20 Psi. If you look at the pressure map for this design you will notice that to make even 17 Psi at the A/R that you need for the 2.0 L DOHC, the turbine would have to spin at upwards of 125,000 RPM and would fail. Also the Air Charge would be somewhere to the order of 250 Deg Celcius.
I know you were generalizing, just thought you would be interested in this info. (2thumbs)
Later...Brian(nana)
It'll make it (actually to about 22-23) up to about 5000 rpm's- both on the DSM and the MSP then fall off to about 15-16. Been there, done that with both. To respond to the next reply (below yours) yes, they blow hot air at 15 psi, however- they are still cramming more into the motor. I have known guys to go very quick (12's) with T25 DSM's without even running a line to their wastegate- just maxing out the turbo. Effecient, no. Makes a bit more power- possibly
.Joe
PS- Just fyi- my dyno #'s kept climbing with boost, so the hot air wasn't hurting it as much as boost was helping itkwiktsi said:It'll make it (actually to about 22-23) up to about 5000 rpm's- both on the DSM and the MSP then fall off to about 15-16. Been there, done that with both. To respond to the next reply (below yours) yes, they blow hot air at 15 psi, however- they are still cramming more into the motor. I have known guys to go very quick (12's) with T25 DSM's without even running a line to their wastegate- just maxing out the turbo. Effecient, no. Makes a bit more power- possibly
Joe
. Just a not- my pulls were done on C16 race fuel witht he proper precautions, don't try this at home .- :
- MP5T / 944
DiscreetSpeed said:
I do not want to start another flame war here so don't jump on this hard please. Hopefully we can squash some misinformation without pissing off the entire Mazda Board.
As you know, Mazda designed your MSP with an IC for a modest 6 PSi. Turning up the boost makes the turbo have to spin faster. As the turbo approaches the surge limit, it looses efficiency and the air charge gets hotter, much hotter. Are you trying to tell me that you know for a fact that a little T-25 with a surge limit of 17 Psi won't heat up air like a ******* afterburner over 15 Psi? Never mind the stress that is being placed on the supporting Bering. I don't know what you know about this little T-25 that I don't. To make 17 Psi with the A/R ratio required for this 2.0L DOHC engine the turbine on paper has to spin at speeds close to 125,000 RPM.
It's a mouse, not the HULK. It was designed for modest Boost and quick spool, it was not intended for 15 Psi. 15 Psi requires a totally different compressor like a T3/T4. (As you know )
You will have a hard time backing this up. I hope this was a joke or something.
Later...Brian
- Status
