Gt3071r

[blueceligts]

Hey guys,

I was looking at some Garrett turbos and was wondering what your thoughts are on using a GT3071R turbo. Would it be too big or laggy do you think? I hope to turbo one day and I am always looking at the different turbo options out there. Seems like many people think the Garrett 28s are too small. I guess I am looking for somthing that has a bit more room for growth other than the GT2871R. I understand boosting a GTS over 6-7 lbs requires internal upgrades. Just looking for opionions here. I already have some headwork done such as a light port job, 3 angle valve job, and updgraded springs and valves.

Plan on getting Piper cams for my next purchase. Still debating on Stage 2 or 3. Any and all opinions appreciated.

[Entranced]

a large gt30 is a big turbo, but it's been done. if you plan on stroking the motor, i'd stick with stage 2's as stage 3's might have a higher clearance problem.. also depends on what pistons you decide to use.

from what it sounds like, you don't want to build the block, but you still want power.. so go with a large gt28 and stage 3 cams.

[blueceligts]

a large gt30 is a big turbo, but it's been done. if you plan on stroking the motor, i'd stick with stage 2's as stage 3's might have a higher clearance problem.. also depends on what pistons you decide to use.

from what it sounds like, you don't want to build the block, but you still want power.. so go with a large gt28 and stage 3 cams.

Yeah I did a search for GT3071R and found some good info. Should have done that in the first place but its also good for more opionions. I am not sure on my decision to stroke the motor or not, I dont know if it would be worth it or not. I will definately build the block though if I want to see above 300HP. Want to play it safe and not destroy the motor. From what I read on the search I will go with a GT3071R, and MWRs or Turbokits.com kit.

[Smaay]

i already make a kit with the GT30R did you do any searching?

[blueceligts]

I did a search Smaay. I didnt read through them all though. Your big boy kit has that turbo in it correct? I did see a thread on where someone wanted his smaay big boy. But I didnt see much about confirming the turbo you used in that kit. I have searched for a post about your big boy kit cause I was curious one day but I could find what I was looking for. What are the details on your Big boy kit?

[Entranced]

search under something called the final product or whatever.. it's titled weird and should be edited to include big boy kit as a keyword.


but either way, if your looking to build the block. definatly get smaay's kit.. it's the best one out there IMO if your going for a big performance kit.

[bt216]

i already make a kit with the GT30R did you do any searching?
:werd: search bt216 Reader ride

[blueceligts]

I found the Final product thread. Thanks!!

[Jesse IL]

gt30
GT30R
search bt216 Reader ride
GT3071R is not the same as what you guys are talking about. GT30R = GT3076R. Larger compressor. Also some GT3071R's are internal wastegate.
I found the Final product thread. Thanks!!
The turbo in the "final product" thread is NOT The turbo you're asking about.

The real question is what are your goals? A GT3071R should be a very good turbo, but ay advice is misguided without you saying what your goals are. It also depends on what GT3071R you're talking about? Some of them are extremely similar and will flow about the same as the 56 trim GT2871R. Were you to feel the need to upgrade from the GT2871R, you would want to go with the external wastegate version in probably the 0.64 A/R.

Regardless, the compressor is about identical between the two as long as you're talking about the 56 trim so the overall airflow capability will be the same. However it is possible to get a bit more efficiency out of the turbine at high rpm on the GT3071R, especially the external wastegate version. You'll sacrifice some spool-up, but if you're going for absolute peak hp numbers, you'll squeeze a bit more from a GT3071R.

[blueceligts]

GT3071R is not the same as what you guys are talking about. GT30R = GT3076R. Larger compressor. Also some GT3071R's are internal wastegate.

The turbo in the "final product" thread is NOT The turbo you're asking about.

The real question is what are your goals? A GT3071R should be a very good turbo, but ay advice is misguided without you saying what your goals are. It also depends on what GT3071R you're talking about? Some of them are extremely similar and will flow about the same as the 56 trim GT2871R. Were you to feel the need to upgrade from the GT2871R, you would want to go with the external wastegate version in probably the 0.64 A/R.

Regardless, the compressor is about identical between the two as long as you're talking about the 56 trim so the overall airflow capability will be the same. However it is possible to get a bit more efficiency out of the turbine at high rpm on the GT3071R, especially the external wastegate version. You'll sacrifice some spool-up, but if you're going for absolute peak hp numbers, you'll squeeze a bit more from a GT3071R.

My end goals are probably around 450. But I do want to start off with your average WHP of around 260. Then save the cash to build the block if i so desired while still having a good turbo that will spool at a decent rpm. With a set of piper cams and pfc i could always bump my rev limiter up a little since I have updgrades in my cylinder head already. And if I didnt decide to build the block, then i would still want to have a good fun turbo, with the option to build always there. I have read the GT2871R is only good for upper 300s. but I think i would want something to peak more around 450.

If i did build the block I would probably set the boost pressure so i would be running around 315-330 whp daily, but if i needed to up the boost to 450 then i could. I hope that helps a little more.

[Jesse IL]

My end goals are probably around 450.
GT3076R

[blueceligts]

GT3076R

what is the spool up on that turbo?

[Jesse IL]

what is the spool up on that turbo?
Somewhat crappy. You want big whp, you pay for it on the spoolup. If you go with that turbo, stick with the 0.64 A/R. I've ridden in an MR2 with a 2.2L stroker 3S-GTE and that exact turbo and it doesn't exactly come right in off idle.

If you want better spool and are willing to live closer to 400 whp (probably a bit more with a great tune), go with the 56 trim GT2871R (Garrett P/N 743347-2). I'm actually building a kit with Smaay right now based on the 48 trim version of that turbo (my goal is below 400 whp). If you contact Smaay, he can probably get you a manifold, downpipe and the whole rest of the setup right now, as he is currently building this around a turbo I supplied him. There will even be a very good base map available for this that I'm developing.

The thing is, you would probably be way happier with that smaller turbo. I think most people who say they want huge hp numbers are just bench racing and/or looking for fame on the internet. Unless you've driven a high whp FWD car with a large, laggy turbo, you probably don't know what you're getting yourself into. I drove Smaay's car when it was putting down 390 whp on a GT3582R and it was asically all lag and wheelspin. You just simply can't put that type of power to the ground. To use that kind of power, you're talking rolling into it on the highway.

I am one of the few proponents on this site of smaller turbos. Having driven turbo Celicas with both small and large turbos, I can say that the small turbo cars are much more fun to drive on a daily basis.

[Smaay]

yeah but when we came home at 545 it was suck the seat up in your *******

[blueceligts]

Thanks for all great info Jesse. I think when the time to buy comes around I will stick with a GT2871R.

[Jesse IL]

yeah but when we came home at 545 it was suck the seat up in your *******
How's the racecar? Getting the thing over to fab so we can get the show on the road?

Also, as you remember, the car was essentially undriveable under boost and you had to basically park the thing ;)

[Jesse IL]

I realized something last night. I may have somewhat misled you.

The GT3071R and GT2871R (56 trim) are pretty much the same thing. The compressor side of these two turbos have the same specs and should flow identically. The differences are mainly coming in the other part of the turbo.

The biggest difference here is that you have the larger T3 CHRA, which has a beefier shaft. Although I've never found evidence to back this up, I have been told that the GT2871R's are prone to failure due at the upper end of their fow range due to the smaller T25 CHRA with it's smaller shaft. Again, I have found no evidence to support this and furthermore, a version of the GT2871R is used as the OEM turbo on newer Skylines and Silvias. So if this were a big concern to you, the CHRA on the GT3071R is in the same family as the GT3076R. However, this means it is more massive and therefore will take longer to build boost.

The next diference comes in the wheels themselves and this is dependant on which version of the turbo you go for: internal or external wastegate. On the external wastegate, this is the exact same turbine section as the larger GT3076R. You could actually interchange this turbo directly for what bt216 has on his car and use the parts already designed around his car. Since the T3 turbine housing is physically larger than a T25, you would proably want the 0.64 A/R, which will flow comparably to the 0.86 A/R on the smaller turbo. This turbine will definitely outflow the GT2871R, which to you means better high rpm performance. But it is also larger, so combined with the more massive CHRA, you will suffer in the spoolup. That said of all GT3071R variants, I'd go with this one due to the external wastegate and excellent turbine housing design. The efficiency of the external gate and the cast-in nozzle on the housing are really nice features that will make the turbine operate very efficiently and will make up somewhat the penalties from the CHRA and turbine wheel in regards to spoolup. I'd also go with the 4" ported shroud compressor, which will make the turbo less surge-prone at low boost and off-idle. Again, this is the same compressor housing bt216 has so everything would be interchangable with his car, you're simply subbing in a lower flow compressor.

The interal wastegate versions of this turbo are somewhat odd to me. Garrett is saying that these are the "highest flowing" internal gate turbos they offer. This is true but somewhat misleading. Reason being is that they're specially machining the larger turbine wheel to fit in a T25 housing. The T25 housing is smaller than the T3 and it is generally felt that the 0.64 A/R is too restrictive for the design of the 2ZZ. So in this case you're definitely going to want a 0.86 A/R. So you're getting slightly more flow than a comparable GT2871R because the turbine wheel is larger and due to the machining to fit in the housing, the trim is very high. So this turbo would slightly outperform the GT2871R at high rpm but again suffer in spoolup. The reason I say it's misleading is that they don't say how it would perform against the external wastegate version (it should perform worse) and they also aren't listing the downsides of your slightly better high rpm performance over the GT2871R (due only to increased turbine efficiency, NOT additional flow capacity).

So hopefully that gives you a much more complete comparison and a better idea where to go with your decision. To me, you're getting marginally better top end performance and possibly a more robust turbo (if you want to believe that hype) at the expense of low end performance and transient boost response. For me, this minor gain is not worth it and makes the GT3071R really an odd man out in my book. To me, if I wanted more I'd probably bypass that step and go right to the GT3076R.

[blueceligts]

Thanks for info Jesse, it will help in my decision when I go to buy a turbo. Thanks!