T28 vs. T25

[JRwerks]

hey everyone i've had my T/28 on my S13 Sr20det for about 2 months now its a ball bearing from the zenki s14 blacktop i've searched didn't really find
anything...

i dont have 550cc injectors,z32 maf, or tuned

should i go back to my T/25 since i juss daily drive???

good advice would be nice thanks everyone...

o and one more question a T/28 at 8psi and a T/25 at 8 psi do they run the same power??? i would figure the bigger turbo runs more since its bigger...

[murda-c]

You should just go NA for the increase in gas mileage.

and sell your t28 to me for 50 bucks.

[clark]

you didn't state whether or not you are experiencing a problem.

were we just supposed to assume that..? i'm stumped.

[95KA-Turbo]

It's actually called a GT2570...but since S14s don't have bigger injectors you'll be safe on stock boost. S14s obviously have different MAFs and ECUs though.

[Sileighty_85]

Maybe this will help
http://www.zilvia.net/f/showthread.php?p=2068836#post2068836


your probably not at this same power level I have alot of mods done
But I dyno'd My T-28 on stock S13 SR ECU, Injectors and MAF and it was leaning out after .8 Bar

[golfer17]

It's actually called a GT2570...but since S14s don't have bigger injectors you'll be safe on stock boost. S14s obviously have different MAFs and ECUs though.

I think you were looking for gt2560 (typo?). anyways, the s14 t28 is a gt2560r-1 (gt2560r-4 for the s15 t28), and it should make around 30whp more than the t25 with almost no loss in power at higher boost levels (the test I am citing this information from was ran at 1.2 bar).

to the original poster, you needn't go through the trouble of swapping your smaller turbo back in, as there wouldn't be much point to it. the t28 will make more power and spool just as fast (ball bearings are wonderful). your stock injectors are the same size as the s14's stock injectors, and if you are still keeping it on stock boost, then you definitely aren't maxing out your injectors or maf. I would imagine the ecu should be able to adjust for it pretty easily too, but just to be safe, you should put a wideband in the car to monitor this (make sure your afr's are at least under 12.5, and preferably in the 11's). also, if you are still on stock 240sx fuel pump, it'd be a good idea to go ahead and change that out for a bigger one.

[Sileighty_85]

to the original poster, you needn't go through the trouble of swapping your smaller turbo back in, as there wouldn't be much point to it. the t28 will make more power and spool just as fast (ball bearings are wonderful). your stock injectors are the same size as the s14's stock injectors, and if you are still keeping it on stock boost, then you definitely aren't maxing out your injectors or maf.
It's actually called a GT2570...but since S14s don't have bigger injectors you'll be safe on stock boost. S14s obviously have different MAFs and ECUs though.

Um I belive the S14 SR uses larger injectors (480cc cant remember exact size) to accomadate the larger turbo.
The link i posted is my Dyno run with an S14 T-28 BB Turbo and @ .8Bar on 370cc inj. I was leaning out in the top end, so I dont think Nissan would run 370's with a T-28.
Also when I had my PFC hooked up for Testing/ information purposes,Injector Duty Cycle was 90-100% at .9 Bar

o and one more question a T/28 at 8psi and a T/25 at 8 psi do they run the same power??? i would figure the bigger turbo runs more since its bigger...

since the T-28 is lager it will push a larger volume of air than the T-25,
so A T-28 @ 11psi will push more air than a T-25 at 11psi, thus creating more power
So a T-28 at 10psi is equaled to a T-25 at 14 psi...(Not exactly accurate but just to give you an idea)

[bo2o]

is there anything wrong with your setup?
get a safc, 480cc injectors, and or wideband.

[whereda40at]

does anyone have a pic of the t25 and the t28 right next to eachother to compare them in size???
im just wondering how much the size difference is.

[Sileighty_85]

Its a Pulsar GTI-R turbo Basically same thing, give ya an idea
S14 Housing just looks differnt

http://i73.photobucket.com/albums/i235/Neil_85/VFSH1527.jpg

[whereda40at]

Its a Pulsar GTI-R turbo Basically same thing, give ya an idea

http://i73.photobucket.com/albums/i235/Neil_85/VFSH1527.jpg
damn it i forgot that i was at work and cant see pics:doh:
i will look at it when i get home at 2am. damn night job.

[gunmetalr32]

thew t/28 iss wayyy bettter

[JRwerks]

nothing is wrong with my car juss dont wanna risk anything...

im running a good amount of mods also:

dc turbo manifold
megan outlet pipe
3in downpipe/cat delete pipe
3in full exhaust
hks intake

and im runnning 10psi on the t28 right now... anything wrong with that???

[Sileighty_85]

and im runnning 10psi on the t28 right now... anything wrong with that???

You "might" be safe with your AFR's

If you look at my dyno sheet you will see that at 11psi it will run lean (Too much air, not enough fuel. Which is bad)

So you really need to get some 550cc's and A Tune

[JRwerks]

Thanks Silieighty_85 So I Should Juss Keep The T/28 And Save For Injectors And Tuning?

[Sileighty_85]

Thanks Silieighty_85 So I Should Juss Keep The T/28 And Save For Injectors And Tuning?

Youp,

oh dont forget the Z32 MAF

[Gjohnson7]

Ok, is it just me. Or do these turbos look different??? The one on the right looks slightly larger.

Its a Pulsar GTI-R turbo Basically same thing, give ya an idea
S14 Housing just looks differnt

http://i73.photobucket.com/albums/i235/Neil_85/VFSH1527.jpg

[Sileighty_85]

Ok, is it just me. Or do these turbos look different??? The one on the right looks slightly larger.

Yes they are differnt
As stated above

The right is a T-28 Non-BB off a RNN14 Pulsar GTI-R
and the left is a Stock S13 T-25

[Gjohnson7]

Ok, I misunderstood what you where saying at first. I thought pic was suppost to be the T28 bb and the Pulsar GTI-R.

Yes they are differnt
As stated above

The right is a T-28 Non-BB off a RNN14 Pulsar GTI-R
and the left is a Stock S13 T-25

[golfer17]

Um I belive the S14 SR uses larger injectors (480cc cant remember exact size) to accomadate the larger turbo.
The link i posted is my Dyno run with an S14 T-28 BB Turbo and @ .8Bar on 370cc inj. I was leaning out in the top end, so I dont think Nissan would run 370's with a T-28.
Also when I had my PFC hooked up for Testing/ information purposes,Injector Duty Cycle was 90-100% at .9 Bar



since the T-28 is lager it will push a larger volume of air than the T-25,
so A T-28 @ 11psi will push more air than a T-25 at 11psi, thus creating more power
So a T-28 at 10psi is equaled to a T-25 at 14 psi...(Not exactly accurate but just to give you an idea)

No, they are 370's, the same size as the s13 injectors. But I can't blame you with all the incorrect information flying around the internet these days. I even remember reading some people saying they were 380's, or something, probably got 370's confused with 480's (the nissan s15 480cc injectors are the only rwd sr20det injectors that are not 370cc).

And you're right about your duty cycle being so high as well, even on lower boost (which is why I never ran more than 11psi on my stock injectors). Though I think the stock injectors tend to flow slightly more than they are rated at as well, since when I had a set cleaned and flow tested, they were all rated at around 410 (though I'm not sure on the cleaning process, they might have been opened up slightly on a lathe to yield this flow rate)

btw, for anyone who is interested, I have an s14 ball-bearing t28 for sale. go here for more info
http://www.zilvia.net/f/showthread.php?t=197102

[Pho Man]

^^
Yep both s13 and s14 injector size is the same. On my s14 blacktop I was running 370cc stock injectors and running 15lbs on high boost 10 on low and 7ish without the controller on.

My 90 is currently under the knife and getting a Redtop done and i'll be running my T28 with front mount and turbo outlet pipe downpipe and exhaust with no moddification to boost. This car will be my Daily Driver. The guy that's doing my build told me that i would be fine at stock boost levels but if I wanted to up the boost i would need to get a boost controller and something like a Apexi AFC Neo to adjust the A/F ratio.

[JRwerks]

whats the max psi that u can run on a T28?
and the max u can run on a T25?

[Ca_Silvia]

T28=18psi
T25=14psi

Those are what you can run effeceintly

[golfer17]

T28=18psi
T25=14psi

Those are what you can run effeceintly

From the compressor map on the s14 t28, it looks as though 16psi is closer to the point where efficiency really drops off quite a bit. Though you will still make a little bit more power on 18psi than on 16. This was confirmed at the track when i trapped 110mph on 16psi and then 111mph on 18psi (it was a hot day, good traction but low trap speeds: for reference, 13.5psi trapped 106).

[flip3d]

ok ok ok...

so you can run a t28 @ 7psi on a stock s13 redtop no problem?

i have no idea what the bar to psi conversion is. .8 bar is what psi?

edit: k, .8 bar is 11psi. dont flame me. im sick in bed. too lazy to search.

[JVD]

ok ok ok...

so you can run a t28 @ 7psi on a stock s13 redtop no problem?

i have no idea what the bar to psi conversion is. .8 bar is what psi?
Not 7psi.

It's called google.

[Ninjabread]

don't run anything more than 7psi, your afr's get scary, TRUST ME.

[mr_240sx]

7 psi with t28 on s13 sr is totally safe.

[golfer17]

ok ok ok...

so you can run a t28 @ 7psi on a stock s13 redtop no problem?

i have no idea what the bar to psi conversion is. .8 bar is what psi?

edit: k, .8 bar is 11psi. dont flame me. im sick in bed. too lazy to search.

the stock wg actuators are set to 8psi on the s14 t28. that would probably be fine on a stock redtop sr20, but i highly recommend that anyone who mods a boosted or nitrous car have a wideband inside to make sure their afr's are safe. Just as a reference, whenever I boosted up my stock t28 to 11psi (the max i was willing to run on my stock injectors and maf) I increased fuel pressure to about 44psi base in order to get my afr's into the 11's and ensure everything would be safe (on the other hand though, I have a friend who boosted his stock t28 up to 14psi on stock injectors and maf with no tuning and afaik it could still be running).

[Boost_me]

For refrence:
0.5 Bar = 7.25psi
0.75 Bar = 10.9psi
1 Bar = 14.5psi
1.5 Bar = 21.75psi
2 Bar = 29psi, And so on and so forth.....

[Pho Man]

the stock wg actuators are set to 8psi on the s14 t28. that would probably be fine on a stock redtop sr20, but i highly recommend that anyone who mods a boosted or nitrous car have a wideband inside to make sure their afr's are safe. Just as a reference, whenever I boosted up my stock t28 to 11psi (the max i was willing to run on my stock injectors and maf) I increased fuel pressure to about 44psi base in order to get my afr's into the 11's and ensure everything would be safe (on the other hand though, I have a friend who boosted his stock t28 up to 14psi on stock injectors and maf with no tuning and afaik it could still be running).



I ran 15lbs on my stock t28 with stock injectors and maf and had no problems at all. I ran a 13.0 @110mph. That's on just some all-season tires with a crappy 2.1 60ft time. I spun 1st and 2nd.

[Sileighty_85]

don't run anything more than 7psi, your afr's get scary, TRUST ME.

Youp, when I dyno'd mine over .8 Bar my Max AFR's were 17.5!!! so yeah nothing more until you get some injectors
http://www.zilvia.net/f/showthread.php?p=2068836#post2068836
I ran 15lbs on my stock t28 with stock injectors and maf and had no problems at all. I ran a 13.0 @110mph. That's on just some all-season tires with a crappy 2.1 60ft time. I spun 1st and 2nd.

Your leaning the shit out of your engine, lower your boost before you weld the pistons to the cylinder walls

[Teambadrun]

The T25G from an S13,SR20 is the same as the S14 turbo. Except the larger front wheel and housing. ( SO THE REAR IS THE SAME 100% ).

Althou the Japanese S14 turbos are all Ball bearing.

The S15 turbo's have a divider in the exhaust housing to bring up boost faster .

The S14 turbo will drink LESS fuel then the T25G as the t25G hit's boost so early your just using fuel even cruising.

Goodluck with what you wanna do..


S14 T28
INTAKE
60

46.6

60.1
EXHAUST


62

53.8

41.7

0.64

PS13 T25G

INTAKE


60

43.3

56
EXHAUST


62

53.8

41.7

0.64

Oh and safe boost before remapping your ecu is .9bar.. *( 13psi) anything over that your asking for it as the AF:R goes past 13.0xxx

Ive ran a S14 T28 turbo on a redtop S13 on 13psi with manifold,intake,exhaust etc etc safely on 13psi and the af;r was around 12.5 without a tune and i was happy with that back in the day.. the turbos will handle much more boost but your stock ecu wont.. afreind of mine actually made 171rwkw on his CA18 + T with a t25G on 22psi ..bahah that thing was pretty quick and the turbo lasted well over 5 months of drifting , street and on the track.. and hes a good drifter

[JRwerks]

thanks everyone on the goood advice.. and i noticed that i do save more gas with a t28 at stock boost i can drive around town and it doesnt really spool so quickly like the t25

[corey240]

so the safe-zone boost on the t28 with stock injectores and maf has changed like 3 times. I just installed mine on my redtop and that turned out to be more pita then i knew it was but worth it. I dont wana overboost and theres alot of mixed information going around now. Stock MAF, and injectors on an s13 sr, what is the level of boost you can safely use befor af start to freak out?

[Sileighty_85]

so the safe-zone boost on the t28 with stock injectores and maf has changed like 3 times. I just installed mine on my redtop and that turned out to be more pita then i knew it was but worth it. I dont wana overboost and theres alot of mixed information going around now. Stock MAF, and injectors on an s13 sr, what is the level of boost you can safely use befor af start to freak out?

Nothing over .7bar (10psi) on stock S13 ECU, MAF, Injectors.
I've posted my Dynosheet link on here 3 times over .7bar the fuel system will lean out

My Dyno sheet @ .8 Bar with T-28 BB, S13 Stock ECU, MAF, 370cc Injectors
http://i73.photobucket.com/albums/i235/Neil_85/Dyno2.jpg

The 17.5 AFR was @ 12PSI
http://i73.photobucket.com/albums/i235/Neil_85/Dyno1.jpg

[Teambadrun]

Nothing over .7bar (10psi) on stock S13 ECU, MAF, Injectors.
I've posted my Dynosheet link on here 3 times over .7bar the fuel system will lean out

My Dyno sheet @ .8 Bar with T-28 BB, S13 Stock ECU, MAF, 370cc Injectors
http://i73.photobucket.com/albums/i235/Neil_85/Dyno2.jpg

The 17.5 AFR was @ 12PSI
http://i73.photobucket.com/albums/i235/Neil_85/Dyno1.jpg
Good stuff dude. Im curious to know how american high octane fuel is ? Must be slightly degraded to aussie fuel??? I was able to run 13psi safely. but hey.. i guess everycar is differnt ? I had a n ARC intercooler on mine back then..

[Sileighty_85]

Good stuff dude. Im curious to know how american high octane fuel is ? Must be slightly degraded to aussie fuel??? I was able to run 13psi safely. but hey.. i guess everycar is differnt ? I had a n ARC intercooler on mine back then..

Mine is fully built, Only stock Valves and cams are being used. everything was replced if out of spec on mine. It runs as if it came from the factory

I find it strange that you can run 13 PSI on Stock S13 Electronics on a T28 with no problems unless you up'ed the fuel pressure.
Do you Have an AFR gauge?
what is ya'll octane rating?
I Run 93 (highest in mt area)

Just because your engine doesnt bog or break up doesnt mean everything is fine. If your leaning out your killing your Piston rings

I ran mine on 12-14 psi at the track a couple of times,
Just did a compression test and saw my #'s dropped 5 psi due to running it lean

[Teambadrun]

It was on a dyno. The fuel is 98 RON... Whats that convert to US fuel?

[one_flip]

I wonder where you got that T28 turbo off an S14 SR20det Blacktop?? LoL keep it stock Jesse!!! Enough with engine problems, don't risk it!!!! Don't wanna end up like the rest... Good luck on that bro!!

[Sileighty_85]

No idea

did you raise the fuel pressure?
Im guessing your running a Walbro Fuel pump?

How much power did you put down?

[Teambadrun]

No idea

did you raise the fuel pressure?
Im guessing your running a Walbro Fuel pump?

How much power did you put down?

It was quite shit actually I only made 135rwkw. But yeah it was extremely hot the dyno also read quite low back then.. lol

[95KA-Turbo]

It was on a dyno. The fuel is 98 RON... Whats that convert to US fuel?

95 RON = 90-91 Octane here in the US...so 98 is much better then what we can get out here with out running race gas. I can get 93 in my neck of the woods but I have seen some gas stations out here only having 91, and I know you can only get 91 in CA.

[Sileighty_85]

It was quite shit actually I only made 135rwkw. But yeah it was extremely hot the dyno also read quite low back then.. lol

135kw=180Hp
Ok so that makes a little more sence, on why ur not running lean
But yeah that is really really low for a T-28 on 13 psi.
Mine made 254whp= 190rwkw @ 10psi you got other issues goin on there if ran it at 13 psi and made barely above stock

[Teambadrun]

135kw=180Hp
Ok so that makes a little more sence, on why ur not running lean
But yeah that is really really low for a T-28 on 13 psi.
Mine made 254whp= 190rwkw @ 10psi you got other issues goin on there if ran it at 13 psi and made barely above stock

Hey there,

In Australia. Our dyno's read more "true" readings. the most, i mean .. the most ive seen. On our local dyno (mainline dyno) a S15, Poncams, PFC, 12.0AF:R awsome tuning , great ignition maps at 17 or so PSI is around 190KW.. So how you got that is weird. But comparing everyone elses power figures on this site.. i believe it.

The most ive seen out of T25G on a SR with cams, etc etc is about 170RWKW on huge boost !! 20psi ish!

But yeah.. It was reading really low on my car so im assuming that's why.. plus the motor had a 1.8mm headgasket...

[JRwerks]

yea i ran my car once at 16psi with the t28 veerrrrryy badddd nothing happened my friend un-pluggeed my waste gate to see what will happen but that was only once but wow the power it had lol...

iono i think now i rather just stay with the t25 with bolt ons thats enough power for meee