# garret T25 turbo questions...



## VWbohica (Oct 9, 2000)

I have an option to turbo my 16v and the shop said that they would put in a garret T25 turbo and and SDS fuel management. The tuner mentionned that i should be pushing about 250HP and the advantage of the garret turbo is that it spools up instantly..i.e there is no lag. he also said that i wouldn't be able to make 300HP with this turbo since it's too small but i'm not looking for massive HP..just something fun and fast that doesn't cost me my first born...
i guess my question is do you guys have any experience with this turbo and if so...how good or how reliable is it??


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## roccostud (Jun 7, 2002)

*Re: garret T25 turbo questions... (VWbohica)*

my friend has a garret T25 in his 84 nissan 200sx, i would go for it. any bigger your going to get bad lag and if your engine is all stock on the inside it could cammage the engine if you went with a bigger turbo.


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## enginerd (Dec 15, 2001)

*Re: garret T25 turbo questions... (roccostud)*

What compressor are they going to be running, its just as important, if not more important than the turbo side. I have seen charts showing a T25 turbo with a T3 compressor flowing enough for 280 HP at the crank. Should spool better than a T3/T04 combo. Might want to look in to the GT25 series turbos if you want more power, and lag is a concern 
http://forums.vwvortex.com/zerothread?id=442548


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## draculia (Feb 27, 2002)

*Re: garret T25 turbo questions... (enginerd)*

a t25 is a tiny turbo that will run out of breath after 5500 rpms. it comes stock on 2nd generation eclipses and talons, among others. spool is instant, and annoying. if you want a better alternative, get a 50 or 60 trim t3. you won't need to worry about lag nearly as much as with any t3/t4, and the top end will blow the t25 away.


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## scottuk (Mar 17, 2001)

*Re: garret T25 turbo questions... (draculia)*

Why do you say "spool is instant and annoying!???..I thought instant response was biggest issue with turbo's and the quicker the better http://****************.com/smile/emthup.gif 
My scooby turbo has terrible lag and my t25 on my golf can blow it away in ALL gears and still pull to 140mph easily...So dont knock it until youve tried it,which i have for the last 3 years.


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## GTI RB (Aug 25, 2000)

*Re: garret T25 turbo questions... (scottuk)*

T25 is too small. I mean you could run it, but why!? Unless you never plan to run more then say like 10lbs and don't like to rev it out. You people speak of "lag" on the T3 like its the boogey monster, its halarious. If you want 10lbs of at 1.5RPM(why would you? no traction) then get a roots blower like an eaton. If you want full boost around 2700-3200k and hold it eficently to redline(if your head can flow enough for the high rpm) then get a T3 .48 a/r w/ 60 trim. It can flow 200 some HP while being efficent, the exact #s i dunno. If you want more power but are willing to live with some actual "lag"(not this "lag" the T3 supposedly creates) then get a t3/t4 with the proper trim and a/r. Even with this you can set it up to get full boost pretty early. I believe billy t got his 1.8(without N2O) to build full boost on a t3/t4 around 3500RPM or so. Can't totaly remember but it wasnt too bad. I'd rather make power up top, low down TQ steals the show, high reving HP makes the dough.


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## VWbohica (Oct 9, 2000)

*Re: garret T25 turbo questions... (GTI RB)*

Thanks for all the replies http://****************.com/smile/emthup.gif (and keep them coming)
I was doing some research about different turbos (i.e. GT25, GT30, T3...etc) and i realized that all the info available on the net can be quite overwhelming. what i have manged to find so far is that the GT25 turbo is the smallest turbo available, it's very reliable and makes good power down low. the drawbacks are that it's not well suited for higher RPM ranges so i don't know how well it will suit the 16v motor as this is a high revving engine. the main reason for my interest in turbo is the $$$ factor... this setup was quoted at about $5k CDN (about $3k US) versus nearly 10k CDN for an all motor setup delivering 191 WHP. basically what i am looking for is a setup that would deliver +200 HP and feel like a NA car (i.e being very drivable) as this is my daily driver. I don't really want masive HP but just enough to surprise a few people when needed








Now to begin with my knowledge of turbos is fairly limited so if you guys have any links that would help me become more knowledgeable about turbo sizes, compressor setups and boost, please let me know http://****************.com/smile/emthup.gif








BTW how does the T3 compare with GT25...i am not talking about the 60 trim but some of the smaller trims available..


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## enginerd (Dec 15, 2001)

*Re: garret T25 turbo questions... (VWbohica)*

don't confuse the T25 with a GT25, they are different animals. GT25 can push between 250 - 450 hp. would be a good option for a 16V. the T25 would prob be strained to put out 250 hp. 


[Modified by enginerd, 5:11 PM 11-24-2002]


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## KILLACABBY (May 25, 2002)

*Re: garret T25 turbo questions... (enginerd)*

IF u think u can get 250hp from a t25 keep dreaming. I had one on my car and the best it would do was 181whp at 12psi.( dta standalone, 500cc injectors big fmic) That sucks!!!! swapped it out for a 14b talon turbo and had 261whp at 12psi. The t25 was instant power but ran out of puff at 5500rpm or so.


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## 80vwpickup (Sep 22, 2002)

*Re: garret T25 turbo questions... (draculia)*

quote:[HR][/HR] if you want a better alternative, get a 50 or 60 trim t3.[HR][/HR]​did any cars come with these? If so what?


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## Jefnes3 (Aug 17, 2001)

*Re: garret T25 turbo questions... (80vwpickup)*

The end of the Saab 900's (befor GM got involved, last made in'93)
T3 50 trim, other saab trubos are t3 45 trim.
Double check me, as i am not 1000% sure say 80%...
Jeffrey Atwood


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## imaradiostar (May 4, 2002)

*Re: garret T25 turbo questions... (VWbohica)*

Could be wrong on this but aren't T25's available in various trim/sizes like other turbos? I had thought that was the case...
Some cars using T25's made over 200 Hp from the factory (210hp on a mitsu eclipse GSX IIRC) on a 2.0 16v engine. I think a smaller turbo on a 16v would be great. The early boost could make up for the lack of torque. VW does this on their 1.8t engine in many cars.
Another thought- many T25's I've seen are water and oil cooled....they may be able to handle higher rpm's than a similar-sized turbo that's only oil cooled.
My opinion- if you're looking for something that's daily drivable and feel stock then you might be better off just swapping in a VW 1.8t. IF you're willing to do the work, SDS engine management and a T25 should give you about 200 horsepower and do it relatively reliably. Just be prepared to spend as much turboing your 16v as you would on a 1.8t. Your other option would be to use some other kind of engine management that you could get for cheap at a junkyard- maybe digi1 or something from another turbo car that you could adapt.
my 2 cents.
jt


[Modified by imaradiostar, 5:40 PM 11-25-2002]


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## macdadmorgan (Jun 6, 2001)

*Re: garret T25 turbo questions... (imaradiostar)*

if you expext you car to drive like a na car with a smaller turbo, your way off base. it will totaly change your power ban, instead of gradully building power as it gets to the top, all your power will be in the low end and peater off in the upper rpm. totaly oppisite of the na 16v. you will also have traction issues. a bigger turbo will hold the caricteristics of a na motor more so then a smaller turbo.
now what do guys think about a T28 on a 16v, i want something bigger then a t3super60, but not as big as a t3/t4, does the t28 fall in between the two?


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## VWbohica (Oct 9, 2000)

*Re: garret T25 turbo questions... (macdadmorgan)*

I have been doing a lot of research on the net lately to clarify what my options are....
as someone pointed out, i've learned that the T25 and GT25 are two different turbos....i still don't know how different these two are. is it safe to assume that the GT25 is just a newer version of the T25????








also, i agree that the driving dynamics of a FI car wil be different than a NA car...but what i am hoping for is a setup that is ideal for daily (city) driving with minimal lag. all my research indicates that the T25 turbo runs out of breath at about 5500 rpm...whether the GT25 is similar, i don't know
i did inquire into getting a 1.8t..but the cost is + $12000 CDN







as opposed to a 16v turbo setup at about $5000. i agree that the 1.8t would be ideal but i can't justify spending this kind of $$$ on the car right now.


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## mattblak (Jan 31, 2002)

*Re: garret T25 turbo questions... (VWbohica)*

quote:[HR][/HR]I have been doing a lot of research on the net lately to clarify what my options are....
as someone pointed out, i've learned that the T25 and GT25 are two different turbos....i still don't know how different these two are. is it safe to assume that the GT25 is just a newer version of the T25????[HR][/HR]​i don't know specifics but i *think* the thing that differentiates the GT-series turbos is their dual-ball-bearing setup.
but enough of my conjecturing, check http://www.turbofast.com.au/GTseries.html for a decent comparo with some hard data. T25 is at the top.
there are also some cool turbo calculators on the site- if you'd like to save a little time, the TurboMatch program suggested a T3 with a compressor trim of 50 and an exhaust trim of .63 for a 7000rpm intercooled 2L 16v running roughly a bar of boost.
someone else in the thread mentioned the T28, and i'd like to prod that along further with a little more info- the nissan s15 (current model) silvia uses a ball-bearing T28, and makes 250hp *stock*. you can occasionally find these turbos on ebay, but if you want a T28, make sure it comes from an S15-series SR20DET engine. any other silvia turbo has a normal T25. personally, i think one of these units would be just about perfect for a street-duty boosted 9A (or ABA16v).
[edited to add clarification]


[Modified by mattblak, 9:59 PM 11-25-2002]


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## Jefnes3 (Aug 17, 2001)

*Re: garret T25 turbo questions... (mattblak)*

A T28 is just a T25/T3 hybrid turbo.
T25 turbine for fast spool-up
T3 Compressor for lots of feed.
This my be something you want to try, but do not try to make too much
power as the turbine is quite small and will 'cork' the power. (limit exhaust flow)
My best guess is don't try to make more than 230-250 hp. 
The T25 is sized for 'smaller' engines, say 1.3-1.6L. Remember the
rest of the world (not US) considers 2.0L to be 'big'. I am helping
a buddy put on on a Sentra 1.6 (yeah, with the 4 speed)
A 'nice' T28 might be:
T25 compressor with mid to large A/R with
a 50 trim T3 compressor.
Good for around 240.
Jeffrey Atwood


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## VWbohica (Oct 9, 2000)

*Re: garret T25 turbo questions... (mattblak)*

I was actually looking at the sylvia turbo setups just to get an idea of how much difference the T25 and T28 make. 
The S13 (SR20DET) engine came equipped with the T25 and made 205HP @6000 RPM and 203 ft/lb @4000RPM. stock boost set at 7PSI.
Turbo specs: compressor--> T25, 60 Trim 56mm BCI-1 compressor
turbine-------> T25, 62 Trim 53.8mm 0.64 A/R
The S14 (SR20DET) engine came equipped with the T28 and made 220HP @6000 RPM and 203 ft/lb @4800RPM.
Turbo specs: compressor--> T28, 60 Trim 60mm BCI-1 compressor, T-04B Housing
turbine-------> T25, 62 Trim 53.8mm 0.64 A/R
The current generation S15 (SR20DET) engine comes equipped with the same T28 and makes 250HP @6000 RPM. 
Turbo specs: compressor--> T28, 60 Trim 56mm BCI-1 compressor, T-04B Housing
turbine-------> Inco turbine wheel, cast divider wall.
I realize that the same turbo bolted on the 9A will not make the same amount of HP but it's interesting to compare the stock numbers from these turbos. there is only an increase of 15 HP from switching from a T25 to a T28....admittedly the T28 can make more power than the T25. the site i got the info from cites that the T28 setup on the S14 can easily make 250HP at 13 PSI whereas the S15 setup cam make 300HP at 15PSI. I would settle for the T25 if the differences in responsiveness (read lag) are significant. my reasoning is that i don't want to sacrifice the responsiveness for a few more horses....
can someone inform me as to how the lag issue is on the T28 as compared with the T25???


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## draculia (Feb 27, 2002)

*Re: garret T25 turbo questions... (VWbohica)*

gt series turbos use different wheels, that are much more efficient. the t25 sucks plain and simply. i know what its like, i have one on my eclipse. you can get t28s with an upraded turbine wheel too. they are expensive and not worth it. get a t3 and call it a day. my boost is set at 16psi on my eclipse, i'll hit that before 3000rpms, it them starts to drop after 5500rpms and by 7200rpms its down around 10psi. it has no top end.


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## scottuk (Mar 17, 2001)

*Re: garret T25 turbo questions... (draculia)*

Read my post higher up ..Subaru Impreza v golf with a t25 who wins have a guess








Btw the t25 blows not sucks


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## GTibunny16v (Aug 12, 2001)

*Re: garret T25 turbo questions... (scottuk)*

I have a t3 super 60 trim .63 A/R . It was orignally on a G60 motor 8:1 compression. The turbo started to spool @ 2400rpm and was at full boost @ 3200rpm. It pull strong up to the 6500rpm redline. Now it's on an ABA 2l motor w/ 8.8:1 compression and spools 200-300rpm sooner. Its very annoying with the quick spool time. Wheel spin is horrible in 1st-3rd gear. Boost is set at 12psi on pump and 15 on race gas.
I think the t3 super 60 would be a good turbo for a 16v running 10psi. With 9:1 compression and the 16v head (flows more air than 8v) More compression and more flow though the head will make the turbo spool quicker (if thats what you want) and not run out of breath at 7000rpm like the T25. 
If you want a turbo that makes 220whp @10psi this would be the turbo. If you want to make 250+whp. I'd go with a T3/T4 50 trim .48a/r. It wont spool until 2700-3000rpm and will probably make full boost around 3500rpm. 
Turbo lag is not some horrible monster that you should avoid. If you want your motor to have alot of low down power and not rev it past 6000rpm much. Go with a roots type supercharger. If you want to rev your motor and make top end power (ie 16v motors) go with a larger sized turbo. 
If you are lowering compression from 10:1 to 9:1 expect to loose a few hp off boost. But you can compensate by bumping fueling and timing with the SDS. Im saying that your car will feel pretty much like stock off boost and when it spools. Hold on and have fun


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