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Garrent T25 efficiancy limit



  Mustang, S13, AX GT
not very high, if you get it on roller bearings then you can get 13-14 PSI, standard I think 8-9 PSI is about the limit IIRC, but I'm a newbie when it comes to this turbo stuff so I could be a million miles out...
 

Waitey

ClioSport Club Member
  Alpina D3, AC Cobra
I thought people with S13's could run 1 bar/13psi happily on a STD tubby?
 
  172 Cup
they will handle 15-16psi no problems. only downside to these is because they are a small turboboost does tail off higher in the revs.
 
on a .49 houseing, a full t25/25 will handle circa 20 psi no problem at all, i used one on my first 5 turbo, running the above boost pressure.

it will make full boost silly early in the rev range and expect it to be on its arse after 4.5k rpm:)
 

Waitey

ClioSport Club Member
  Alpina D3, AC Cobra
I just want it to hold 11.8 to the red line without sending inlet temps sky high.
 
  Mustang, S13, AX GT
I thought people with S13's could run 1 bar/13psi happily on a STD tubby?
I dont think so? I know that mines only running around 7-8PSI and I was advised to put it on roller bearings if I wanted to run it much over.
 
  E46 M3, x2 GTT, RS250
on a .49 houseing, a full t25/25 will handle circa 20 psi no problem at all, i used one on my first 5 turbo, running the above boost pressure.

it will make full boost silly early in the rev range and expect it to be on its arse after 4.5k rpm:)

My five had a T25 and it would run as much as the actuator would handle which was 34 psi. Turbo dynamics said it would run 15psi minimum but it was more like 18-19. Like you say hardley any lag it would be making boost at 1600rpm and by 3600rpm it would hit 34psi and hold 31-32.

That word "tubby" seems to get used to much, it sounds so gay, you make it sound like a girls toy,
 
  172 Cup
I thought people with S13's could run 1 bar/13psi happily on a STD tubby?
I dont think so? I know that mines only running around 7-8PSI and I was advised to put it on roller bearings if I wanted to run it much over.

i had s13's for about 3 years mate so i know a fair bit about them! 15psi is fine as long as you have supporting mods ect like fuel pump, different map ect.
 
  172 Cup
obviously i am talking about an s13 t25. other t25's with different sized housing's and core's will offer different results.

some skyline turbo's have a ceramic core and you cant take them much above 10psi.
 

Waitey

ClioSport Club Member
  Alpina D3, AC Cobra
Well mine died at 12psi. But it was old. Going to buy a new one now.
 
  Golf GT & A4 Avant
A standard T2 from a 5 Turbo is efficient to about 14psi/ 1bar although it'll run out of puff at about 6000rpm. Generally I've not seen a T25 run any less than about 12/13psi when fitted to a 5 Turbo, but I've seen plenty turned up to 20+psi running reliable
 
  172 FF
I think my fiesta turbo had a t2 on it & could do 1 bar easily.
Something to note though. I got a refurbed one when I rebuilt my engine & killed it a couple of times at high boost because my oil pressure wasn't high enough at high temps. So make sure your oil pump is working well at temperature if you are gonna be turning the boost up, just in case.
 
  Clio 172 mk2
on a .49 houseing, a full t25/25 will handle circa 20 psi no problem at all, i used one on my first 5 turbo, running the above boost pressure.

it will make full boost silly early in the rev range and expect it to be on its arse after 4.5k rpm:)

My five had a T25 and it would run as much as the actuator would handle which was 34 psi. Turbo dynamics said it would run 15psi minimum but it was more like 18-19. Like you say hardley any lag it would be making boost at 1600rpm and by 3600rpm it would hit 34psi and hold 31-32.

That word "tubby" seems to get used to much, it sounds so gay, you make it sound like a girls toy,

Hate the word 'tubby' as well...is it easier to type than turbo or something?

True on the T25, good turbo and IIRC fitted to later Escort cosworths for the reduced lag. Easily handle 1 bar
 
  Tangoed Works
Its not just at what PSI it becomes a hot air pump.

Dont you have an intercooler? Doing things such as chargecooling / bigger intercooler / water injection, will all cool down the inlet temps allowing you to run higher PSI.

Then you have the problem of how much boost your standard pistons and rods can take, so the amount of boost you can and want to run are determined by this.

Also, the more air going in, the more fuel you will need to put in. What cc are the injectors and can they flow enough juice to avoid pinking.

BTW Garrett is just the name of the turbo manufacturer. You have others such as IHI, KKK etc
 
s not just PSI though its also engine breathing you can make it usless at 1psi if you run it on a bigger engine.

also what spec etc matters.
 


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