what's the max psi a stock t25 can handle?

JCell · Sep 26, 2005

I searched but only came out with guesses

it's been said that 15psi is it's limit, others say 18, others say 12 witch is bs (rlaugh)

anyone have hard data supporting it's limit?

mp3moose · Sep 26, 2005

Search for compressor effieceny on the t25. I believe it loses efficency around 14 or 15 psi, but I don't recall exactly. I know the map of the compressor is around a lot of places online though.

yashooa · Sep 27, 2005

It is efficient to around 15-16PSI. It can make power above that but I would imagine heat would not be your friend

This is aimed at the stock MSP turbo so I don't know how it compares to an older t-series vs the GT-series.

icespeed · Sep 27, 2005

yashooa said:
It is efficient to around 15-16PSI. It can make power above that but I would imagine heat would not be your friend This is aimed at the stock MSP turbo so I don't know how it compares to an older t-series vs the GT-series.

how do you read that chart??? It doesn't seem that that is the correct chart for this question.... What does the P and C mean in "P1c/P2c". P=pressure (in psi, bars, mm hg?) C= constant??? what's the constant??? Also, the bottom numbers are air flow, not psi. That's too much calculus than I'd rather do, just to figure out max psi, as opposed to max air flow.

CasopoliS · Sep 27, 2005

icespeed said:
how do you read that chart??? It doesn't seem that that is the correct chart for this question.... What does the P and C mean in "P1c/P2c". P=pressure (in psi, bars, mm hg?) C= constant??? what's the constant??? Also, the bottom numbers are air flow, not psi. That's too much calculus than I'd rather do, just to figure out max psi, as opposed to max air flow.

airflow and pressure are completely different
the left side is ratio of inlet and outlet pressures, probably Corrected
The data you want to look at is the various curves and how they "lay out"

yashooa · Sep 27, 2005

http://www.msprotege.com/forum/archive/index.php/t-109146.html

Spooled · Sep 27, 2005

CasopoliS said:
airflow and pressure are completely different
the left side is ratio of inlet and outlet pressures, probably Corrected
The data you want to look at is the various curves and how they "lay out"

Yep, and you realy need to know how much your head flows. We were talking about that a while ago. I think the FS-DE flows something like 183 stock (intake side) and someone flowed about 210 after porting and polshing, etc.

Here is the thread: http://www.msprotege.com/forum/showthread.php?t=109817&highlight=flow+bench

TampaSport20 · Sep 27, 2005

too vague of a question....there isnt necessarily a "MAX PSI".....a T-25 could pump out 20PSI if pushed hard enough, however at that point it's just a big heat pump, so you start losing air flow.....air flow is what makes power, not pressure

I think the question you are looking to get answered was already answered previously

T-25 loses efficiency around 14-15PSI

CasopoliS · Sep 27, 2005

14 psi always seems to be a good number. but remember 14psi on a T25 is not the same as 14psi GT28RS (or other) and that is why people replace the T25.

apocman · Sep 27, 2005

Dont forget we have a T25R aka: GT25R just OEM version, there is a difference between the t25 and the T25R/GT25R turbo...

They either replace them or have them upgraded for real cheap. MPNick for $580 can upgrade the compressor side to the GT28R guts and port and polish the turbo, exhaust manifold, and S-pipe...

whatever their choice is, they should be quite happy with them... and of course there are some people who just run the stocker at 15psi....

kicker22705 · Sep 27, 2005

http://www.msprotege.com/forum/attachment.php?attachmentid=48551

the ideal area to be in is the most centered elipitical area where it it says 73% efficiency, aka the sweet spot. the further you stray, the less efficient it becomes, calling for a bigger turbo at the higher boost levels.

ala the gt28rs...w/ its massive sweet spot, if i recall correctly it had a sweet spot for our motors that ranged from 12-22psi where it would be within 73% efficiency range.

Pirana · Sep 27, 2005

Sweet info (thumb)

peepsalot · Sep 28, 2005

icespeed said:
how do you read that chart??? It doesn't seem that that is the correct chart for this question.... What does the P and C mean in "P1c/P2c". P=pressure (in psi, bars, mm hg?) C= constant??? what's the constant??? Also, the bottom numbers are air flow, not psi. That's too much calculus than I'd rather do, just to figure out max psi, as opposed to max air flow.

Atmospheric pressure is 14.7. Pressure ratio of 2 would mean that the turbo is outputting 2 times atmospheric pressure, 2*14.7 psi. But since your reference for boost is pressure above atmospheric, then you would say a pressure ratio of 2 would give 14.7psi of boost.

(Pressure Ratio-1)*14.7 = (output boost)

Turbos don't really care about the absolute amount of pressure, only the ratio. So a sequential turbo setup for example could make lots of boost since you would basically get to square the pressure ratio. (boom01)

apocman · Sep 28, 2005

Yashooa, sent me this link it a great read!!!! It is a forum discussion between a few turbo specialist even has some of the turbo designers from Garrett...

Looks like the T25R/GT25R can be modified to handle over 400hp, They even show an article by some of them that down plays the Disco Potatoe(DP) laughing about the fact a modified T25R/GT25R can out flow and reach much greater HP than the DP and as far as the spool time, almost no difference between the two....

Kind of makes me feel glad I did the upgrade versus buying the DP....

sorry added the link...

<HR style="COLOR: #d1d1e1" SIZE=1> 
http://forums.freshalloy.com/ubbthreads/showflat.php?Cat=&Board=UBB9&Number=67583474&page=&view=&sb=5&o=&fpart=1&vc=1

Spooled · Sep 28, 2005

The only reason I see to upgrade to a bigger turbo is if you plan on pushing more than 1 bar or over 250 whp. Then, like apocman said, you can do some modifications to the GT-25R and make some great power while spooling extremely fast. blkzoomzoom has proven what you can do with the stocker.

apocman · Sep 28, 2005

As a matter of fact I have two of those MPNick stage 1 turnbo upgrades sitting in my garage. One kit is going on my car this weekend!!!

I also have the MPNick custom 80mm MAF that Black ZZ had and is 10lb wastegate...

Spooled said:
The only reason I see to upgrade to a bigger turbo is if you plan on pushing more than 1 bar or over 250 whp. Then, like apocman said, you can do some modifications to the GT-25R and make some great power while spooling extremely fast. blkzoomzoom has proven what you can do with the stocker.

CasopoliS · Sep 28, 2005

if the inlet of the turbo is only 2.25 (I think), why get a larger MAF / Intake? Just curious.

apocman · Sep 28, 2005

Becuase I could get the MAF and wastegate for the same price as I could buy a rebuit stock MAF and the MAF has never been used. IT is designed to be used for 300hp plus.

here was Black Zoom-Zoom reply to me:

Background of a MAF:

The MAF sensor determines how much airflows into your engine (using hotwire(I won't get into that)) and converts that data into a voltage signal. It sends the signal (0-5volts) to the pcm, the higher the voltage the more air the pcm is expecting thus the more fuel. Once the voltage reaches 5v the pcm shuts off the fuel supply because in a stock system it should never reach that high and determines there is a problem.
If you want to make more Hp it takes more air. You have to get around reaching the 5v from the Maf.

Want more Hp and accuratley tune it?

To do that you have to increase the amount of air into the engine and be able to register it. This bigger MAf sensor increases the amount of air per voltage. This allows you to accuratley read how much air is getting into the engine, unlike the stock maf which you have to cap the voltage to run more hp(fcd). This makes tuning 50x's easier and accurate. On top of that it gets rid of the honeycomb and restriction of the stock maf.

On top of all that it looks impressive as hell.
--------------------------------------------------------------------------
I talked to BiggTimm as well:

Also BiggTimm has one by Nick and he said it makes the turbo crazy loud which makes it sound really cool and mean and he said it makes your car sound like it's going to jump up and turn into the hulk and assrape all cars within a 2 mile radius

ok, ok the last part about hulk I added, but it adds to the story...

CasopoliS said:
if the inlet of the turbo is only 2.25 (I think), why get a larger MAF / Intake? Just curious.

Spooled · Sep 28, 2005

Put you need to have a piggyback to scale the fuel maps, in case anyone is wondering about that. I'd like to get my hands on a Z32 MAF once I have some sort of fuel/timing controller.

Pirana · Sep 28, 2005

It would be beautifull to get an AEM and convert to MAP!!

what's the max psi a stock t25 can handle?

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