GT2871 vs GT3071-WG vs GT3071

[Beemer832]

So I am having this personal debate with myself on the differences of these three turbos:
GT2871 vs GT3071-WG vs GT3071

GT3071-WG and GT2871 are internally wastegated, the GT3071 is not. All of them are T25 (or have the option to be). They come in different AR sizes (which for the life of me I am still trying to learn).

If I am looking for a turbo with decent low end torque and can still pull strong up top which turbo is right for me? I would LIKE to keep the APR manifold which well help keep costs down, but its not imperative.

Just trying to get some research done before I start buying parts and run into issues. Thanks guys!

-josh

[Militant-Grunt]

Get an external wastegate, you won't regret it. If you're looking to get significant gains over your APR kit then go with the 3071r. The lag isn't too bad, if you don't care about lag too much then get a 3076r.

What are the specs on your motor?

[nagumneetum]

The GT2871 and the GT3071 are both rated to 460hp`as I understand it the GT28 is good for low end and medium range power and the GT30 is good for medium to top end power...
but then again that all depends on the AR... you could lower the AR on the 30 and have more evenly distributed power or increase the AR on the 28 and have the same results?
But evenmore that all depends on the complete setup ie. injectors and software...

Not to highjack the thread but Militant-Grunt you are running a 3076 @ 25psi... you running that on a 1.8 with stock internals? if yes is it an AEB or ATW?

[Seerlah]

The APR Manifold is not designed for external wastegate, so if you want to keep the hardware you would need to run an internal wastegate turbo charger. Or simply replace the manifold. And if you were to do that, it would be better to go T3 as the spooling will come on faster. But you run more chances of snappings rods as to compared to a T25.

My suggestion would be to add drop in rods (either Scat or Integrated Engineering) and do it properly. SPA (or another T3 manifold) T3 flanged Turbo Charger, turbo charger of your choice, and supporting mods. That is what I would suggest. Or T25 and stock internals.

Or if you would want to keep low cost while keeping your APR hardware, you could simply upgrade to a GT2871R internally wastegated Turbo charger. The A/R basically is basically how your spooling would be. .63 A/R will grant faster spooling, but low top end power (like the k03, it will die up top). .82 A/R will spool a little later and have more top end power. If you decide to keep the APR hardware, then I would go with the GT2871R internal wastegate .82 A/R. If you currently have an APR Stg 3 kit on your vehicle, you would be simply swapping out turbo chargers and everything should bolt right back up. You can re-use oil and coolant lines also.

Also, if you looked in the builds section there is a person whom proved that a GT3071R internal wastegate turbo bolts up to the APR manifold. That is always another option. And many people will tell you the GT2871R is the most "fun" street turbo. But after a while, the hunger for more power comes into play.

[djwimbo]

Running a turbo of that size through a T25 manifold is choking the exhaust flow of the turbo. I'm not against the 3071WG, but it won't make as much power as a externally gated 3071. I can't talk you out of a 2871, as they are great turbos for the 1.8-2.0L cars that aren't going for 400whp(even though a fully tweaked 2871 on a transverse car could probably hit that).

If you're looking to get everything redone, call up 034 and see if they can't tweak their "stage 3" kit for your needs. Not that you can't keep the manifold and DP if you go 2871, I'd just upgrade now instead of down the line when it would cost more.

That's my $.02 at least.

[onemoremile]

A 2871r would be a fun street setup with plenty of power for most people. It should be able to run a mid to high 12 second 1/4 mile pass and boost threshold and response will be more enjoyable day to day. If you had a T3 manifold it would be a more difficult decision and I would lean towards the 3071 for street or 3076 or hta3076 if you did a lot of higher rpm track days or went to the drag strip often. If your engine has stock rods then the 2871r is the only sensible option.

[Beemer832]

Thanks guys, this is exactly what I was looking for.

I am trying to keep costs down and would LIKE to keep the APR manifold, but if I can get a decent amount of $$ for it then might as well upgrade something to a sidemount or topmount like the SPA or FR.

To answer the question about the engine.. (i am ashamed that you guys haven't seen my engine build thread :( )

scat rods
calico coated main and rod bearings
raceware main studs
custom pistons
hastins rings
83mm bore
head is stock minus the exhaust valves which are....incolnel, cant think of the brand. mike2ptzero sold them to me.
stock intake and retainers and springs at this time.

I guess I am back to square one looking at the full gt3071. If I go this route it will be vband DP and WG. That setup is too tempting to pass up.

I am also looking into a variable vein turbo setup. I will be posting more info about this possible project later.

thanks again guys
-josh

[djwimbo]

If you're doing a full bottom end build, it almost would seem a waste to run the 2871R.

If you've got the girl of your dreams naked in front of you, it seems a bit out of line to continue humping the sheets.

Keep in mind the APR manifold isn't a pile of gold, you're not going to make bank off of it. Awhile back somebody tried selling one for $500 and everyone laughed at him.

The VNT/VGT turbos have a lot of potential, the problem is that outside of the diesel world, controlling the technology can be a problem. I know there's at least one SEM system out there that can be used, but I don't recall which one.

I'm a big fan of the Full GT3071R setup, I doubt you will regret that one bit.

[Beemer832]

i just dont want somethign that isnt going to boost until 3500-4000rpm. I want it to be streetable without bringing it to redline ALL the time. And I mean by that, in BOOST all the time :-)

I have always liked the 3071 setup but there is no one local to me (Kansas City) for me to take a ride in their car...

WAIT.. bingo... I am heading back to CT on June 10th for a friends wedding. I will be in Danbury, CT. Who is offering up rides of a GT2871 and GT3071? I'd be willing to meet up with them somewhere as well has buy them a round of drinks afterwards.
I KNOW there are plenty of big turbo guys on the east coast, don't hold out on me now :)


and another side note, the engine has already been built so i stopped dry humping it a few weeks back ;)

-josh

[STS9king]

I have the 3071-wg bolted to apr stg 3 mani. I went with the 3071 over the 2871 just b/c I have goals for the future and going for 350awhp on pump with a 3071 is more doable than 2871. I am also building the head so I can rev out to 8k-8500k, thus utilizing the 3071 w/ .86 ar to its full potential. If you just want to bolt something up and be done with it and not tweak or tune any further, I would say get the 2871. If you want to go for more power with further tweaking and software/injector changes, go with the 3071. Also, doing a different manifold for your setup puts you back to square one. You will need, new down pipe, intake setup, possibly oil and coolant lines, waste gate, blah blah blah $ $ $ $ $. The reason I stayed with the apr stuff is b/c i didn't want to spend an extra grand or two doing a full new setup and this manifold flows more than any log manifold and is super high quality. Also, if your not going for 500+hp, you will be just fine running a internally gated setup (i have had t3/t4 setups with external wg's and they sound crazy when vented to the atmosphere but thats about it (when staying at lower hp numbers).

Does my 3071 spool like the 28r with tiny hot side??? hell no, but above 5k rpms, there is probobly a 50hp gain just from changing turbos. But I have a huge restriction at the moment (two cats and a 2" bottleneck in my joke of a down pipe and 2.5" exhaust with two mufflers and a resonator). Next week I will have a 3" turbo back with no cat and one muffler and I will report back with the giant difference in spool I will see. Also, apr stage 3 software is not ment to turn a 3071 so once i get a good 630 file, that will make all the difference in teh world too.

IF you have future plans and want to keeping tunning===3071
IF you want to bolt something on and be done with it===2871

[Beemer832]

thanks for the info STS. i REALLY need a ride in a gt3071 and gt2871 car. guess i am off to the new england boards to help hunt me down one :)

seeing is believing sometimes.

-josh

[aaronamerica]

go gt30, I have the gt2871 and now I want more power

[gli_ryan]

go gt30, I have the gt2871 and now I want more power

x2

[djwimbo]

go gt30, I have the gt2871 and now I want more power

I haven't driven a 2871R or a 71R-elim car, but I've had the opportunity to ride in one (full 2871R). I know I'd want more power. The 2871R on a 4cyl just feels like a peppy DOHC V8 to me.

[Beemer832]

mmmmmmmmmmmm.... yea i dont want to have to do another turbo swap again in another 6-12 months. looks like the gt3071wg is a good option at this point while maintaining the APR manifold.......

choices choices...

-josh

[Seerlah]

I did not know you had a built block. I would def save up some more money and do a complete turbo kit overhaul. I can not find the ad, but Dougyfresh was selling a GT2871R t25 internal wastegate a little while ago. We know he knows how to take care of his parts, so I would maybe PM him to see if he still has it (I think he was selling it in the price range of $800). If you go this route, you can enjoy the GT2871R (simply replace your blown turbo with this one) till you get tired and at the same time think about what t3 external wastegate route you want to go. Just another option.

[STS9king]

if you get the 3071, try going with the .64a/r. my .86 a/r is slow to spool and I think the .64 should fit with no probs on the apr mani. The reason i went with the .86 is cause I thought that it was the only one that would put the compressor far enough away from the manifold to fit but I think i'm wrong. If your fir a .64, I think i will swap out my .86 for a .64.