PDA

View Full Version : Upgrade: GT25R v. GT30R



Punch
08-21-2004, 04:46 PM
Within the next couple of months I will be upgrading the stock T25 and am considering either: the GT25R, or GT30R.

I was planning on going with the GT25R until I read a few posts indicating the spool up of both are nearly identical, but the GT30R can handle more WHP.

While my WHP goals are around 360-380, they may change and I don't want to waste money upgrading when I should have purchased the turbo with the most potential in the first place. So, is the GT30R the one to go with initially, since it has the same characteristics as the GT25R, or should I get a GT25R if I don't plan on making over 400 WHP (for now) anyway. I may just be happy with 360 WHP and never want more power, so which one is it? TIA.

silviapwr20
08-21-2004, 09:22 PM
The gt30r is going to require a new manifold/downpipe, where as the gt25r is a direct replacement for the t-25.

DuffMan
08-22-2004, 01:47 AM
Who told you the spool up was the same???

BlackBomber
08-22-2004, 07:01 AM
Within the next couple of months I will be upgrading the stock T25 and am considering either: the GT25R, or GT30R.

I was planning on going with the GT25R until I read a few posts indicating the spool up of both are nearly identical, but the GT30R can handle more WHP.

While my WHP goals are around 360-380, they may change and I don't want to waste money upgrading when I should have purchased the turbo with the most potential in the first place. So, is the GT30R the one to go with initially, since it has the same characteristics as the GT25R, or should I get a GT25R if I don't plan on making over 400 WHP (for now) anyway. I may just be happy with 360 WHP and never want more power, so which one is it? TIA.



neither....if you are concerned about having the ability to upgrade in the future, then go with a top mount setup now and start out with a t3/t4 50 trim with a stage 3 wheel. this turbo will make close to 370-380 but more importantly will:

1. Save you a little money being around $550 (turbo alone)
2. Allow you to build a platform that is upgradeable using the t3 flanged top mount manifold.

Let say one day you're ready to step up to 450whp or so then you can just sell that turbo and upgrade. This is what I plan on doing.

PSI240SX
08-22-2004, 07:30 AM
And if you decide to take Blue Bomber's advice, PM me because I can get you a log manifold, and o2 extension for a T3/T4 that will bolt to your SR downpipe for $250 brand new.

gunluvS14
08-22-2004, 08:26 AM
that's a very nice offer Jay

Hugh
08-22-2004, 09:43 AM
There you go...

Turbob15sentra
08-22-2004, 10:54 AM
Might want to try out an SC61 from Precision.. Believe it or not.. this turbo spools up at the same RPM that a 50 trim will.. but is capable of 575-580whp. It uses T3/T04E housings, so it bolts on like any other T3/T4 would.

Travis

Hugh
08-22-2004, 12:44 PM
And that was my turbo of choice before I changed my mind and went bigger with the full-race turbo.

killjoy
08-22-2004, 02:00 PM
I thought the sc61 spooled at like 45- 4700 rpms? I had the 50 trim and it spooled at like 3600.

BlackBomber
08-22-2004, 03:12 PM
I thought the sc61 spooled at like 45- 4700 rpms? I had the 50 trim and it spooled at like 3600.



you may have had the b-housing... my friend had the b housing on his b18 and it spooled nastily around 3600-3800. it was still a 50 trim compressor though. I can tell you a friend of mine has an SC61 on his sr20 with stock head and he hit 15psi right around 4500.

bl200sx
08-22-2004, 03:38 PM
ya, you realy can't wrong with the cheaper t3/t4 turbos, figure your power goals from there, if you need more power or not, just go bigger. A 50 trim t3/t4 turbo is pretty damn sweet power upgrade, compared to a tiny t25.

killjoy
08-22-2004, 09:07 PM
I thought the sc61 spooled at like 45- 4700 rpms? I had the 50 trim and it spooled at like 3600.



you may have had the b-housing...



I had an E housing.

BlackBomber
08-23-2004, 06:26 AM
I thought the sc61 spooled at like 45- 4700 rpms? I had the 50 trim and it spooled at like 3600.



you may have had the b-housing...



I had an E housing.



how much power did you make?

DOBA
08-23-2004, 06:27 AM
Seems like the GT25R and the GT30R just went out the window..how does the T3/T4 comapre in response and lag?
I was planning on the GT25R (my goal is 330hp or so) but looking through posts everyone seems to recomend the T3/T4.

killjoy
08-23-2004, 06:56 AM
People are recommending the hybrids because they are cheaper and you can get the pwoer levels you are suggesting with these turbos so there is no need to go ball bearing...Also, Jay I made 342 with the sc50, (t3/T04E, .63 stage 5 turbine wheel.)

Punch
08-23-2004, 06:58 AM
neither....if you are concerned about having the ability to upgrade in the future, then go with a top mount setup now and start out with a t3/t4 50 trim with a stage 3 wheel. this turbo will make close to 370-380 but more importantly will:

1. Save you a little money being around $550 (turbo alone)
2. Allow you to build a platform that is upgradeable using the t3 flanged top mount manifold.

Let say one day you're ready to step up to 450whp or so then you can just sell that turbo and upgrade. This is what I plan on doing.



[/QUOTE] So, what's all the hype about the GT25R when the t3/t4 makes the same amount of WHP, is it in fact that spool up is quicker? BTW, where can I get to the T3/T4 for the price you mentioned. Thanks for the help.

killjoy
08-23-2004, 07:02 AM
The "hype" as you put it is because the 25r fits on the stock manifold and no external wastegate is needed either, so even though the turbo is a grand, you can *save* money so to speak but not having other thing sto upgrade. With the hybrids you gotta switch manifold and buy an external wastegate, etc.

Enthalpy
08-23-2004, 07:10 AM
So, what's all the hype about the GT25R when the t3/t4 makes the same amount of WHP, is it in fact that spool up is quicker? BTW, where can I get to the T3/T4 for the price you mentioned. Thanks for the help.



I'm going to tell you that the spool isnt any faster with T3/T4. I've dyno tuned more SR/Turbo combinations than anyone on this board. and the truth is as follows:

GT25R (.64 A/R) - 18 psi-4000 RPM (360 hp)
T3/T04E 50 trim (stg3, .63 A/R) - 18 psi-4200 RPM (370 hp)
GT25R (.86 A/R) - 18 psi-4400 RPM (385 hp)
T3/T04E 50 trim (stg5, .63 A/R) - 18 psi-4500 RPM (390 hp)
SC61 - 18 psi-5250 RPM (450 hp)

Now that is all on the same dyno with stock displacemnt SR's in 4th gear. you might get slightly better spool on the street in 5th gear. but the only way to trul;y compare is to apply the same load to all turbos. (4th gear on dyno) that is pretty representative of what you are going to get in 2-4th gears on the street. 5th just loads it so hard that it spools faster...but if you are matting it in 5th from 3000 RPM you are just wasting time anyway http://forums.freshalloy.com/images/graemlins/smile.gif All the cars in those dyno sessions had a greddy style intake manifold AND cams. so take from it what you will but those are the facts and an accurate comaprison of the 5 turbos in quesiton.

kthxbye.

killjoy
08-23-2004, 07:14 AM
Geez, Scott, it looks like we both read this board at work... http://forums.freshalloy.com/images/graemlins/wink.gif

Enthalpy
08-23-2004, 07:31 AM
....possibly.....

dryft_s15
08-23-2004, 07:37 AM
What about a stock S15 turbo? Where would it fit into there, mainly in terms of spool? 3500 rpm?

Enthalpy
08-23-2004, 07:47 AM
S15 turbo (GT28R) - 18 psi-3700 RPM (300 hp) (stock cams and intake manifold)

Option
08-23-2004, 08:11 AM
Would it be wise to switch to T3/T04e if you want a less laggy powerban? What does top mount log style manifolds do for responsiveness? Does it help or create more lag? I want the upgradeability of the T3/T04E but i want less lag, more like 3700-3800 RPM, or around that, in the 350hp or simular ballpark. I do alot of drift, acasional autox, and daily driven street car, this is far S14 also btw...

BlackBomber
08-23-2004, 08:58 AM
Would it be wise to switch to T3/T04e if you want a less laggy powerban? What does top mount log style manifolds do for responsiveness? Does it help or create more lag? I want the upgradeability of the T3/T04E but i want less lag, more like 3700-3800 RPM, or around that, in the 350hp or simular ballpark. I do alot of drift, acasional autox, and daily driven street car, this is far S14 also btw...



Who says you have to run a "Log Style" manifold. There are tons of tubular manifolds available now. Full-Race being the current best. Just depends on your $$$$

Punch
08-23-2004, 04:38 PM
So, in short:

1.) I could spend approximately 800.00 for the T3/T4 including wastegate and then spend another $300.00 for the manifold for around 1100.00 to make it work and be able to upgrade in the future or

2.)Buy a GT25R if I want to stick with the horsepower I already mentioned and have it essentially bolt on.

Now, where do I get a decent manifold for a decent price - I saw a few over $1K for a full race setup. I don't want to get anything that will most likely crack. Thanks for all the help. BTW, enthalpy expect a call from me in a few months to tune this thing.

BlackBomber
08-23-2004, 04:43 PM
yes, you are right. but you will need to search for manifold options. I'm guessing it will cost a little more than 300 for a reliable manifold unless you pick one up used or from someone that has one for sale.

consider as well that the gt25r will cost 1100 + custom lines which can either be made for $75-100 (if you are resourceful enough) or bought from taka direct installation for around $150.

Vapor
08-23-2004, 04:58 PM
t3/04 variant will require new lines as well

jickel240
08-23-2004, 06:00 PM
SC61 - 18 psi-5250 RPM (450 hp)






Whoa that RPM seems a little high for that turbo..I'm not doubting you, but I'm looking into getting this turbo very soon, and for not reaching full spool at 5000+rpms, I'd hope to make a little more than 450...What a/r's were on that particular turbo?

Hugh
08-23-2004, 06:33 PM
Fun thing about big turbos, they may not be at 'full boost' until higher RPM, but they will still make more power where the smaller ones peak at, and continue to make more power later. (in my experience)

KSU_S13Less
08-23-2004, 09:01 PM
Fun thing about big turbos, they may not be at 'full boost' until higher RPM, but they will still make more power where the smaller ones peak at, and continue to make more power later. (in my experience)





Very true Hugh.


Scott, great post for boost & RPM vs horsepower output.

However for a truly best comparo multiple dyno graphs of each of these turbos overlayed onto one another would give the best example of the powerband each of these turbos produce. http://forums.freshalloy.com/images/graemlins/wink.gif

Jsquared
08-23-2004, 10:21 PM
i'd like the S15/GT28R (thought they were a bit different?) included as well http://forums.freshalloy.com/images/graemlins/laugh.gif

killjoy
08-24-2004, 06:36 AM
i'd like the S15/GT28R (thought they were a bit different?) included as well http://forums.freshalloy.com/images/graemlins/laugh.gif



S15 turbo (GT28R) - 18 psi-3700 RPM (300 hp) (stock cams and intake manifold)

-Copied from above-

Enthalpy
08-24-2004, 06:56 AM
SC61 - 18 psi-5250 RPM (450 hp)






Whoa that RPM seems a little high for that turbo..I'm not doubting you, but I'm looking into getting this turbo very soon, and for not reaching full spool at 5000+rpms, I'd hope to make a little more than 450...What a/r's were on that particular turbo?



I hope you are kidding? an SC61 is a HUGE turbo. capable of almost 600 wheel HP. it si going to lag...HARD. but the payoff on the top end is worth it!

http://www.enjukuracing.com/ken/racecar/544.jpg

go look at that pic. that was spooolign to 25-26 psi an you can see by the TQ curve that it doesnt get there until 5500 RPM!

Punch
08-24-2004, 07:36 AM
What WHP can I expect for a GT25R w/ just injectors no cams. Also, has anyone dyno'd the GT30R.

Enthalpy
08-24-2004, 07:39 AM
GT25R on stock cams, manifolds, etc does about 330 whp @ 18 psi.

DOBA
08-24-2004, 07:41 AM
GT25R on stock cams, manifolds, etc does about 330 whp @ 18 psi.




And that is MORE than I need!! the perfect setup i think.

jickel240
08-24-2004, 08:28 AM
I hope you are kidding?



That's just an rpm I'd figure full spool would be at with a t3/t67...or a greddy t-78

..not a 61 mm turbo..oh well, I'm ordering mine as soon as get rid of my 20g kit http://forums.freshalloy.com/images/graemlins/grin.gif

Which Sc61 is that? The T04e, or the t04s?

Enthalpy
08-24-2004, 09:04 AM
deosnt matter if it is S or E. compressor housing has litle to no effect on spool. but it was an E

jickel240
08-24-2004, 09:25 AM
deosnt matter if it is S or E. compressor housing has litle to no effect on spool. but it was an E



Seeing how a somewhat small(in perspective) gt25r has an S cover on it, I would have to agree, I was just curious what the power potential difference is between the S and E covers for the sc61. It's a pricey option(t04s cover), and I'm deciding on it's worth to me

Jsquared
08-24-2004, 11:13 PM
S15 turbo (GT28R) - 18 psi-3700 RPM (300 hp) (stock cams and intake manifold)

-Copied from above-


I saw that, I meant for the dyno graph overlay thingy

KSU_S13Less
08-25-2004, 07:35 AM
I saw that, I meant for the dyno graph overlay thingy




Ditto, someone hook up the overlay thingy! http://forums.freshalloy.com/images/graemlins/laugh.gif

Punch
08-26-2004, 07:40 AM
[QUOTE]
GT25R on stock cams, manifolds, etc does about 330 whp @ 18 psi. [/quote

At what RPM? BTW, how does the GT25R/.64 compare with the GT2871R/.64 in terms of spool/whp. It seems to me that they may be very similar.

harlock_ssx
09-19-2004, 12:57 PM
I used to run the S-15 turbo...awesome street turbo. It spools FAST! It doesn't have the potential of some of the other ones, but if you're not racing a lot, I think it's a better choice for an SR you drive a lot. I upgraded to the GT25R .86 AR. It's a bit disappointing initially, as it spools a bit higher, & it's nowhere near as responsive as the old S-15, BUT it pulls a lot better. I just needed to do a LOT of tuning to get the most out of it.
My combo consists of Greddy Intake, 850cc injectors, GT25R ceramic coated & polished, on a Jet-Hot coated SS Autochrome manifold with HKS actuator & Tomei outlet, HKS step 1 264 cams, Tomei RAS, GTiR fans, Z32 mafs blow-through in my intercooler piping. I'll be upgrading to a Q45 throttlebody & installing an OS Giken full crossmission & new clutch with lightweight flywheel, probably next month, then it's off to the dyno! I'm boosting 1.3 with the stock head gasket. The combo has been tuned locally by a friend's speed shop by reflashing the ECU. Fine tuning is handled with an SAFC-2.
One thing about upgrading that pisses me off is the piping...50mm hot pipes just aren't big enough (to me) when you're putting in a much larger than stock turbo. My turbo inlet pipe is 4" ID & all my other piping is 70mm (will be upgrading to 80mm when I swap in the new throttlebody). It cost me a bit, but it can't hurt & looks cool as hell when I pop the hood!

shane_B
09-19-2004, 08:13 PM
This is some great info.

Scott, I am curious about a turbo no one has yet mentioned that Ive been thinking of getting. Precision makes a custom GT30R hybrid. My friend Eric is a turbo dealer and he mentioned it to me. Basically its comes with a T04E or S compressor just like a GT30R does. But the exhaust side is more similar to the GT25R. It uses a LARGE T25 turbine housing and is internally waste gated.. Garret nor precison list it on their site so I cant pull up the specific specs on it. If I remember right it has a ~.64 or ~.80 a/r (cant remember) and flows 54 lb/min. I plan on going with a similar setup as the above post (cams, headwork, intake, havent decided on ECU) If anyone wants more info on it or want someone to explain it better ask Eric. He can check on it again. www.turbotime.us (http://www.turbotime.us)

shane_B
09-23-2004, 11:22 PM
Also, since it has a T04E compressor I will need a top mount. But I dont think anyone makes a top mount with a small T25/28 turbine flange...do they?

mike2016
09-24-2004, 12:36 AM
Check this out
http://www.atpturbo.com/Merchant2/graphics/home_features/3071R-WG.jpg

T25 flanged GT3071R... interesting. maybe a good replacement to GT25R.. ?

kovert
09-24-2004, 12:49 AM
I guess I might be of some help to this thread...

my whole turbo upgrade ( JGS log manifold, turbo, o2 that bolts to blitz/greddy dp's, tial 38mm wg, dump pipe, and oil lines ) cost me right around $800 total.

Its a t3/t04E 60 trim with a stage 3 wheel and .63 exhaust A/R. I cant really tell you the spool because since I installed it i had a exhaust leak that got worse and worse ( till i fixed it today ) spool was around 4500 ( 20+psi ) with a huge exhaust leak.

Although, Im not on stock compression, I am on stock cams and intake manifold. and i made a 355whp and 309tq at 18psi. on 91 octane gas.

the plus side to my setup is...if I wanna go bigger, its easier to find good t3/t4s than t25-t28 flanged turbos. not to mention...top mount so far has been MUCH easier to work on; considering you have good brake MC clearance it is anyway..

Oni_kage
09-24-2004, 05:07 AM
What WHP can I expect for a GT25R w/ just injectors no cams. Also, has anyone dyno'd the GT30R.



give me a month and I will have a dynotuned gt3071. Stock cams and intake manifold(hks cams are sold out everywhere -_-)

here is a pic, I really don't know when I will hit 18 psi...

http://www.sfu.ca/~mbae/s14/turbo%20setup%20001b.jpg

killjoy
09-24-2004, 06:58 AM
Dude, I don't want to burst your bubble but that manfiold sucks. I have broke two. The second one I had three custom support brackets made for it and it still broke. I didn't listen either when people told me, but take it from me. Get rid of it.

Oni_kage
09-24-2004, 07:03 AM
dammmmn, what maniold is it? A hotshot right?

killjoy
09-24-2004, 11:45 AM
yup, avoid it or you will be changing it when it breaks or if it breaks and damages your turbo like Enthalpy's did.

Papa Lazarou
09-24-2004, 12:28 PM
This is some great info.

Scott, I am curious about a turbo no one has yet mentioned that Ive been thinking of getting. Precision makes a custom GT30R hybrid. My friend Eric is a turbo dealer and he mentioned it to me. Basically its comes with a T04E or S compressor just like a GT30R does. But the exhaust side is more similar to the GT25R. It uses a LARGE T25 turbine housing and is internally waste gated.. Garret nor precison list it on their site so I cant pull up the specific specs on it. If I remember right it has a ~.64 or ~.80 a/r (cant remember) and flows 54 lb/min. I plan on going with a similar setup as the above post (cams, headwork, intake, havent decided on ECU) If anyone wants more info on it or want someone to explain it better ask Eric. He can check on it again. www.turbotime.us (http://www.turbotime.us)



You basically just described a GT2540R (or GT25R) as far as I can tell or whatever the proper model number should be now? GT2576R?

Take a look at it, it has a large T04S compressor housing. It can be low mounted though (might have to make a few modifications down there to get it to fit).

It uses either a 48 Trim or 56 Trim T04S compressor as used in the GT30R. I believe most places sell the 48 Trim.

Garrett CHRA Numbers : 700177-0015 (56 Trim)
446179-0018 (48 Trim)

Theres a picture of one mounted on an engine here http://store1.yimg.com/I/phase2motorsports_1808_650646

shane_B
09-25-2004, 11:25 PM
Yeah, there are probably some close combinations. I wonder what kind of performance one could expect from this turbo.

Scott, your Turbo-vs-spool RPM-vs- HP comparisons were great. Do you have more examples of these other turbo's that have been mentioned?

CA_inside
09-26-2004, 06:14 PM
does anybody know more about this gt3071r that has a t25 hot side like hp range pricing where to get one ?

BlackBomber
09-26-2004, 06:36 PM
Are these turbos that any authorized Garret Dealer can sell?

Hopefully so, but here is the ATP Release (http://www.atpturbo.com/)

Here is a test of the turbo on the SRT-4. (http://www.atpturbo.com/root/releases/release051404.htm)

srt-4 is a dohc 2.4 liter. according to the test the car had stock internals, etc. Full boost (20 psi) was achieved by about 3800 rpm which will probably be a little later on the SR obviously being 2.0 liters. it made like 381whp (second dyno graph) on 20psi. Probably make 440-450whp or so on an SR with cams, intake and 26 psi.

Papa Lazarou
09-26-2004, 07:06 PM
Theres some interesting Garrett CHRA's you just don't see being sold.

Theres one listed which uses a 76mm 52 Trim T04S compressor, and a 57mm 90 trim GT28 turbine.

Very similar to a HKS GT2835R but with the bigger compressor wheel of a HKS GT3037 (or Garrett GT30R)

This would be intermediate between the GT25R and the GT30R and IMHO better than the GT25R. Be interesting to see if you can just order it through any Garrett supplier. The CHRA code on this one is 700177-0011. There is also one which uses the 48 Trim compressor and 84 Trim turbine, which is 700177-0010.

Actually just noticed one of these are now listed on Ray Halls site http://forums.freshalloy.com/images/graemlins/smile.gif http://www.turbofast.com.au/GTseries.html

shane_B
09-27-2004, 05:01 AM
This is probably very very similar to the one I mentioned. Is it a "custom built" turbo? (not one they usually will sell but one they can put together for you?) I think if the CHRA isnt listed its b/c they would have to custome build it. I think they can build anything you want really. Tough part is the T04E compressor wont work bottom mount.
I wish I could use the T25 exhaust side with a t04E compressor so I could do a direct bolt on.

asad
09-27-2004, 08:02 AM
Tough part is the T04E compressor wont work bottom mount.



Uh, really? The T04S compressor housing on the GT25R fits (barely) -- I don't think the T04E housing is bigger...

Asad

champa
09-27-2004, 11:04 AM
S15 turbo (GT28R) - 18 psi-3700 RPM (300 hp) (stock cams and intake manifold)



sorry i know this is a little OT but what base timing did you set it to? i have the same turbo on a stock blacktop and put down 250whp @ 15psi with 15 degrees btdc.

champa
09-27-2004, 12:05 PM
S15 turbo (GT28R) - 18 psi-3700 RPM (300 hp) (stock cams and intake manifold)

-Copied from above-


I saw that, I meant for the dyno graph overlay thingy



here is my dyno. it's not an overlay but it's an idea.
http://www.az240sx.org/forums/uploads/post-1-1092589241.jpg

shane_B
10-01-2004, 07:02 AM
Uh, really? The T04S compressor housing on the GT25R fits (barely) -- I don't think the T04E housing is bigger...




Sorry. I tend to mix up compressors. The E isnt bigger. I just thougth the E didnt fit for some reason. Will the S compressor fit with or without modification of the steering?

Enthalpy
10-01-2004, 07:10 AM
My numbersa re with a custom tuned ECU. All cars in my comparison had custom tuned ECU's

asad
10-01-2004, 07:55 AM
Will the S compressor fit with or without modification of the steering?



The compressor housing is nowhere near the steering linkage.

Asad

shane_B
10-01-2004, 05:45 PM
OK, Im really a victim of misinformation here. So what are the clearance issues? This is important b/c up until now all Ive heard is that the steering linkage gets in the way. Im trying to mount something similar to a GT30R but bottom mount. Ive had my turbo off a couple times but I havent tried to test fit anything bigger. In the meantime I'll go do a search!

LOwrestling2001
10-01-2004, 11:08 PM
the compressor on a GT25R will not clear the motor mount bracket without shaving, thats the only clearance issue, other than that its fine.