GT3071 on stock 1.6
 

Hi, im currently looking to upgrade my T25 and ive got the opportunity to get a real bargain on a GT3071 which i understand has the T25 flange

My concern is though what sort of lag would a turbo of this size bring and would i be safe running 12psi on this turbo on a stock motor?? i will have to upgrade my fueling system and get my megasquirt remapped i know!!

any advice would be greatly appreciated :)

thanks

The 30 series has a T3 flange. A gt2871 or 2876 would have the same flange as your t25

Boost threshold will be high. Expect to see full boost at 4500+ RPM. 12 psi will be fine, should put you in the 230-250whp range depending on the timing map/exhaust/etc.

the GT3071 has a T25 flange Aricjm, only one that does i believe!! info on the turbo is here!

http://www.owendevelopments.co.uk/pr....asp?prodId=18

Hmm interesting i dont know whether to give it a go?? the T25 just aint cutting it for me and i cant find a decent T28 around anywhere!!

Not true. Some 30's are t25 flange as well.



As for OP's question: I'd expect it to be laggy. At low boost like that and modest power goals I'd definitely look into something smaller. I'd expect power to come on no earlier than 46-4800rpm

This is incorrect:

http://www.turbobygarrett.com/turbob...R_700382_3.htm

There are also some nice v-band outlet and externally wastegated t25 housings available through ATPTurbo.

a 3071 is a pretty desirable turbo. i'll bet you could swap somebody for a 2860 (maybe even this guy http://forums.nicoclub.com/fs-garret...o-t505829.html) plus cash.

ou should be able to pick up a ball bearing gt28 (from a nissan s15). check the nissan forums.

is it easy to rotate the compressor housing on these turbos do you know?? in its current state the Intercooler inlet would be facing upwards

yes

right cheers guys ive bought the turbo, going to give it a try :)

I would run less than 12psi on a 3071. You're liable to make a lot of power, even at low boost levels, and you don't want to push a factory longblock past ~250whp for any appreciable amount of time.

If you have plans to build a motor for the car down the road, pick it up and keep the boost low. If you never want to build a motor, I would keep your T25.

I would expect that you would see full boost around 4k. 12psi might be kinda high unless u got a real fuel management, pump,injectors, clutch and the list goes on and on. i would defiantly take it and try it out if its not what u want someone will trade for a gt28 no doubt.

yeah ive got all that mate, might need to uprate my injectors and a remap but thats about it!! ill give it a try and if i dont like it ill try and get a swap!! i wont loose money on it thats for sure :)

well if you want I have a gt2871 with minimal use and t25 flange for sale it easily made 250whp on a cast iron log manifold

you will need to "remap"? I hope you're not talking about the stock ECU. The stock ECU has no way of sensing boost, and I sure as hell know you can't "remap" it. With the amount most shops charge, it would be cheaper to just buy an MS anyways.

Read the OP.

lol i know.. if you read my first post properly you would notice i already have a megasquirt!!.. i've had tuned turbo cars for a few years now so i know the score.. i just am not up on the knowledge about turbo specs all the numbers baffle me if im honest!!

i wouldnt go past 10psi... you will be making probably ~235-240hp at 10psi.

but i want to see your dyno graph...i almost bought one for myself.

In for 1.5K RPM powerband

lol I wouldn't imagine it hitting full boost any earlier than 5k.
But when it does, OH BOY will it feel good.


And its not like the car will be completely dead up to that point. just a couple psi from that turbo at 3-4k will already generate some decent grunt

If you want to rape face the power is just an upshift away

This thing will be extremely laggy. I ran a fully built Audi A4 1.9L 9.5:1 compression with meth injection and full 3 inch exhaust all the way through. Got full 24 psi at 4800 RPM.

I've tuned one, 1.6L built engine (Wisecos and Eagle rods) on a '97 chassis.

7psi at 5100rpm, I kid you not.

Honestly, sell it and get a 2560.

just change your redline to 9,000rpm and you will be fine.

OPG's ATI dampner and the mazdacomp lifter kit with intake manifold and cam gears. :)

I've had a bigger turbo on my 1.6L depends on your horsepower goals, I don't understand why people are so scared to go big on a Miata.

Me either.

Because shit breaks at 250whp and that power level can be achieved by more responsive turbo. Assuming stock motor of course.

I'm sure a GT42 turbo fits under the hood, why not try that?

What fun is a miata that doesn't have boost until 5000rpm? The 2871 is probably the biggest turbo I would go with on a 1.8. I've tried all sorts of different combinations on many cars I've tuned and driven, from a smaller-than-T25 on a 93, a 2560 on a '00 1.6, a 2860 on 1.8 '00, a 2871 on 2002 1.8 to a 3071 on a '97 1.6.

I didn't like the 3071 on the 1.6 at all. I loved the 2560 on the 1.6, very easy to drive around at 12psi, hugely fun. The 2002 on the 2871 was a beast (420rwhp at 23psi) but you could still have fun because it made 14psi at 4000rpm, and 7-8psi at 3300rpm.

http://i54.photobucket.com/albums/g9...2/Untitled.png

3076 on my 00 1.8

It is a TON of fun and great around town.
~5psi down low generates enough grunt to be able to get out of your own way, then after 4 all hell breaks loose.
People often forget that with a large turbo flowing large ammounts of air you can massage the ignition down low even at low boost and make up for quite a bit of the "lag"


In a perfect world I'd have a 2L 35R weekend toy and 2560 low boost quiet/soft "daily":D

On the 1.6:

http://users.forthnet.gr/ath/twikicore/graph.png

What do you mean by "massage the ignition down low"? Retard the timing? Im very curious because i plan on getting a T3/T4 50 a/r 57 trim for my stock 1.6. Im afraid this would be to laggy also.

advance it in the low low reigons with no boost to try to keep it quick and retard it right before the turbo spools to help it spool up faster has worked for me.

Pretty much.

And the graph reverant posted is identical to mine in shape but about 1300rpm to the right.

Might be a LITTLE too laggy for a 1.6, now that I see when it hits peak boost:giggle: