GT28rs or stock Turbo

[MSPLIFE]

Well i been thinking it over and over and i don't know what to do so here im, want advise but only from knowleageable people. If i want to keep stock internals for like another year or so and i want to get to 285whp. Do i really need my gt28rs or can i do it with the stocker. And if people boost 14psi on gt28rs whats the most i could boost on the gt25 with halteche6x?

[shane02pro5]

Your saying you want to keep the boost down for now but want the turbo to be able to get to that power level after the motors built right!?

Joka1 ran 22psi on the stock turbo for a long time before blowing the motor. May try and get some info from him.

[zuku26]

You already have the GT28RS in leave it. The Stock turbo is ok but not a great unit. If I absolutly had to run the stock turbo again, It would have to be that was rebuilt by MPNick with the GT28RS internals.
Isn't the stock unit rated for 300 HP? You'll have to almost max out the gt25 to get the numbers your looking for. Your RS is rated to 350. BTW boosting 14 PSI with the GT28RS on stock internals expect the motor to last about one race. 10 PSI on the stocker is just about equal to 6 PSI on the GT28RS. With stock internals I would n't be comfortable boosting more then 7 psi with the bigger turbo. I hope that helps some.
Are you looking to use the stocker because of the boosting issues we've talked about on the other thread?

[zuku26]

I think Joka had a mutant engine!

[MSPLIFE]

no really, i just figure if i only want 270 or so for now the stocker but i mean a brand new stocker should be fine right? b-c when i built the motor i want something bigger than gt28 like a turbo capeable of holding 450+whp. i have the new t25 ready, but i dont know if to replace the gt28sr yet

[shane02pro5]

Definately but I ran 13psi on my VF-22 around 250whp before my built motor.

[MSPLIFE]

what size is the vf22 compare to as the stock or what, and does the gt25 spools faster than a gt28rs?

[Mazdaspeed2oo35]

what size is the vf22 compare to as the stock or what, and does the gt25 spools faster than a gt28rs?

You really don't want a turbo that spools too fast, main reason is your transmission, the faster your turbo spools, the faster and more risk you are running to break your transmission. First of all you need to know what exactly you want out of your car, you want to be fast red light to red light, or you want to be fast and keep up. you can't make your car, fast, with a very responsive turbo and keep up in top end and not break your transmission. if you want to have a fun car use a small size turbo, if you want to be fast and be more competitive in high RPM use a GT28RS or GT2871, but if you want to make real power, and be real fast in mid and top end and make big numbers you need to move to a mid size turbo, GT3071, or GT35R or similar turbos, it all depends what you are looking for, but to be safe and good no matter what turbo you use, you need to Forged your internals, Weld your LSD and or get Stronger 3rd and 4th cryo treated gears and some good clutch.. this is just my .02

[MSPLIFE]

i like a car that im driving and if i hit it, it responds quick. But at the same time if i have 270whp in the stocker wouldn't it be the same as a gt28rs with 270. The only thing is that i probably make the 270 faster with the stocker b/c of the spool time.

[shane02pro5]

You are pushing beyond the limits of the block for sure at 270. I had a J&S knock sensor at 250whp that held things together.

My vf-22 is a little smaller than a 28rs.

The point is the bigger the turbo the more lag you will have which is good for stock tranny and block but it's powerband will be higher in the rev range. So you won't get much until past 3500rpms+

[MSPLIFE]

ok, whats the safe psi on stock turbo with stock motor and the safe whp on the same stock turbo and motor? b/c i know that there really inst to much differense on the spool of the gt28rs and the stock one b/c they both spool pretty quick

[Mazdaspeed2oo35]

You are pushing beyond the limits of the block for sure at 270. I had a J&S knock sensor at 250whp that held things together.

My vf-22 is a little smaller than a 28rs.

The point is the bigger the turbo the more lag you will have which is good for stock tranny and block but it's powerband will be higher in the rev range. So you won't get much until past 3500rpms+

very well said Shane, i rather in my case to make power a little later, and keep up in top end, than having a very fast spooling turbo and run out of breath in top end, also less chance to break the tranny while making power on higher speed, rpm and gear.. my setup makes power from 3.9k all the way to redline, and stays on full boost on every upcoming gears.. is all about what you want and are looking for in a car, i love to make power in mid to top end, and keep up with other fast cars, but i also know people like to have a very responsive turbos setups for like red light to red light races...

[MSPLIFE]

The real question here is, how much of a difference is there between the two turbos as for spooling. Is the gt25 like a monster in spooling compare to the gt28rs or if im careful and race at only high rpms will i be fine.

[Mazdaspeed2oo35]

The real question here is, how much of a difference is there between the two turbos as for spooling. Is the gt25 like a monster in spooling compare to the gt28rs or if im careful and race at only high rpms will i be fine.

if you want to race on High RPM you'll need something bigger than the Stock unit, the GT25 spools very, very fast, but also runs out of breath fast in high rpm. they are both fast spooling turbos just that the 28RS makes more power and hold it more than the Stocker in high rpm. the best in my consideration turbo in the 28 family is the GT2871R, is the fastest spooling in its category and makes power through the whole power band. just remember all turbos are made to make certain amount of power and psi efficiency range.

[shane02pro5]

The gt2871 or similar is probably what I will be going to next.

[zuku26]

What are your current mods so we can help you figure out how to get to your goal?

[MSPLIFE]

with:GT28rs,Vibrant Exhaust with delete cat,Perrin FMI with open HKS BOV,
Walbro fuel pump,All 4 motor mounts,SRI with AEM dryflow filter,and A/F SplitSecond with the Super Stock map i made 240whp.

Right now i got rid of the FMI and undesided about ion FMI or just stocker with methanol. And also got rid of the split second for the halteche6x but still no install. And then the turbo, that don't know if i should change.


In my plans i have t25 at 12psi so the engine dont suffer to much like 10psi from the gt28rs, also haltech with 440ccs injectors tune, 505s intake mani, my new stock turbo mani ported, and 3'' S n J pipes. And the mystery of ION FMI or methanol with stock SMIC. I think that i should easily hit atleast 260whp with this.

[shane02pro5]

Oops I meant gt3071!


The gt2871 or similar is probably what I will be going to next.

[MSPM1cheLe]

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[MSPLIFE]

i got my new stock turbo with new stock mani. Now all is left is making the decision. I think i will run the stocker to test it.

[nvmsp]

So wheres your gt28rs now? I want it if you got it.

[MSPLIFE]

i still have it, but trust me i won't sell it unless i get a fair amount for it. So give me your best offer

[nvmsp]

You tell me how much, I don't now what your expecting to get. Cuz I don't need it, but I'd definitely like to have it to throw it on in the future if the price is right.

[nvmsp]

no rush, but how much u want for it?

[Ricktalife]

what kinda shit do you have to upgrade to make the gt28rs fit?

[nvmsp]

nothing you just gotta turn it or move the wg a little, theres tons of info about it somewhere.

[zuku26]

what kinda shit do you have to upgrade to make the gt28rs fit?

The WGA bracket needed to be fabbed a tiny bit and the oil and coolant lines needed to re directed a small amount. That's about it. In fact I was even able to run the stock plastic piping with it until I got my new stuff in. Well worth it IMHO. I'm only running 5-6 PSI and can tell the difference in power. When I first got it in I was boosting 10.5 PSI It was like a pissed off caged animal trying to get loose. Considering the whole car was stock that was too dangerous. At 6 PSI the car is much more powerful then stock and feels very smooth. Now with the FMIC, the car is responding even better. ApexR1 3" catless J-Mid pipe is on it's way, that should be great!!

[MSPLIFE]

no rush, but how much u want for it?


Well i got it from PG for 1200, so i would't sell for less than 850

[tweetyspeed]

i am actually doing alot of research right now on the turbo i should run... talked to two different tech guys at garret and both of them told me and i quote," the t25 ballbearing turbo will be stable to 18 psi. after 18 psi it starts to blow very hot air." do to the turbo being ballbearing it is going to have a fast spool time. when you check out the two turbo you also want to research the cfm rating on both. i do know the rs has a higher cfm but dont ask me what i dont know. if your target is 270 the either one will do great. as said before the rs will spool just a hair slower and higher rpm boosting is always safer on a motor. my $0.02 are in.

[MSPM1cheLe]

i am actually doing alot of research right now on the turbo i should run... talked to two different tech guys at garret and both of them told me and i quote," the t25 ballbearing turbo will be stable to 18 psi. after 18 psi it starts to blow very hot air." do to the turbo being ballbearing it is going to have a fast spool time. when you check out the two turbo you also want to research the cfm rating on both. i do know the rs has a higher cfm but dont ask me what i dont know. if your target is 270 the either one will do great. as said before the rs will spool just a hair slower and higher rpm boosting is always safer on a motor. my $0.02 are in.

good info. :]

[Jasonboy]

That is very good info. I guess I was mis informed when I was told anything above 15psi with the t25 was super inefficient.

Say ones target hp is 270 as stated above that would still obtained at a lower boost pressure and safer with a gt28rs ? Safer because the air is not getting super heated by the t25 over working itself or because of the same cfm levels at a lower boost ? or both ?

[vel]

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[tweetyspeed]

That is very good info. I guess I was mis informed when I was told anything above 15psi with the t25 was super inefficient.

Say ones target hp is 270 as stated above that would still obtained at a lower boost pressure and safer with a gt28rs ? Safer because the air is not getting super heated by the t25 over working itself or because of the same cfm levels at a lower boost ? or both ?


the rs, do to it producing boost at just a hair later, will be easier on the motor and tranny. it is always less damaging if something has a higher rotating mass speed (higher rpm spool gt28rs) than a lower rotating mass speed (lower spooled t25). i also heard the same thing from many people on this forum. i have learned to trust what the manufacture says over hearsay though. keep i eye out i will be posting som build pics here soon. just finished balancing all my rods and piston to within .0001 of a gram of each other. crank and all is being done as i type this. hoping for a 12k rpm mazdaspeed after i am said and done. at least that is the taget for now. lol

[MSPLIFE]

Man the gt25 feels really good but still since i only want like 270whp im still undecided on which one. B/c when i built the motor i want something much bigger than a gt28. But i think this depends on which of the two turbos i can sell faster. gt28= 850 or almost new gt25 for 650. Which ever one i sell will come with its wg and the lines for water and oil. and for 100 more i can add a stock mani with a hair line crack and in perfect condition stock S pipe. Other than that im planning on slowing down my project b/c i need money.

[tweetyspeed]

dude keep the rs... it will be big enough for you even after your build. plus it will help save your stock bottom end and tranny for the time being if you can keep the boost controller turned down! lol! i have that problem!

[zuku26]

The 28RS is your better option to keep, but also your better option to make money as well. The RS makes more power with less boost. I have mine set at 5-6 psi and I vouch for the car being much faster then with the t25. I'll probably never touch the boost again. Ad far as spool time goes. I have yet to see a diffrence. Even with my FMIC on I have yet to find out what Lag is.