gt2871 dyno

[Nyteryder]

I have had he car running a couple months now w/ enthalpy tune but I just got it on the dyno a few days ago. It is running very rich and I have another tune on the way. What kind of power gains should I expect with some of the fuel taking out. I also have a megan exhaust mani and elbow going on next week. This was done at 18-19psi. I was expecting more power. Do you think I am fouling out my plugs, last I checked they seem to be fine. My setup is in my sig.

[HolyShiznit]

It looks like you are close to 12:1 A/F throughout almost all of the range. That's good. Taking out more fuel is a lil' dangerous. The A/F looks fine to me up until the very end where it nose dives.

[Dori Dori]

I wouldnt shoot for much more power until you get bigger injectors.

[Fenvy]

can I ask what kind of injectors you're running now?

[Dori Dori]

can I ask what kind of injectors you're running now?

His sig says it, 50lb MSD.

[D1 guy]

I had my plugs gapped at 35 b/c thats how they came for the sr motor.......that was very wrong. Im running the .86 gt2871r and at 14psi it started fouling really bad. No power what so ever over 1 bar. I gapped them down to 27 like jeff at HEAVYTHROTTLE told me to do and now my car enjoys 20+ psi. Runs excellent.

[Fenvy]

how many CC does it amount to?

[wildacexxx]

how many CC does it amount to?

around 500

[BaliLover]

That looks about right for a stock head and intake manifold with that turbo in .64 trim considering it wasn't dyno tuned but tuned by enthalpy based on a similar setup. He tuned it a bit on the safe side more than likely since he didn't have the car on the dyno in front of him to extract max power.

[Nyteryder]

Well, sent me another tune, I will be back on the dyno tues. most likely. I was hoping for around 320whp with my exhaust mani and elbow.

[codyace]

300 hp at 18-19 psi seems VERY low, esepcially when custom t28's and disco potato's make ALOT more at equal boost

I suggest cams, at a minimum though....there have been plenty of dynos with more power...so it's confusing yet...

[pakuadragon]

50# injectors are closer to 525cc

50 lb/hr x 10.25 cc/min = 525cc

[Neil]

hm. I was hoping a 2871 would spool up faster than 3500rpm. maybe the manifold and dump will help in that respect.

my megan turbo manifold quality looks awesome but I decided against their dump pipe (got lucky and found a greddy for 150). I haven't seen one in person but I don't think think theyre divided. It does appear to have a lot more internal volume than stock though so that might help negate some of the wastegate turbulence. If im correct and it's got the same fancy *looking* 5 bolt flange as a TurboXS dump, there's a u-shaped cutout between 2 of the 3 bottom stud holes that only allows for 1/16"th of gasket contact.

[BaliLover]

300 hp at 18-19 psi seems VERY low, esepcially when custom t28's and disco potato's make ALOT more at equal boost

I suggest cams, at a minimum though....there have been plenty of dynos with more power...so it's confusing yet...

The Disco Potato (GT28RS) does NOT make alot more power at the same 18-19psi. I had the DP in .86 trim, not the .64 Nyteryder is running with his 2871, and with an Enthalpy dyno tune, 740cc injectors, 3" turbo back exhaust I hit 315hp. This is using a turbo with a larger trim to get higher topend at the sacrifice of quick spool. I blew that turbo and upgraded to the GT2871R in .86 trim and it felt just a tad more powerful but nothing really exciting. Now, I threw in a set of cams the other day and THAT made a huge difference. I'll be installing my intake manifold and getting it retuned shortly and I expect to see around 400hp.

As I recall, I think the .64 trim is good to around 360hp with cams and a manifold with a good dyno tune. As for the spool time, 3500 is about right for that turbo, and the .86 spools around 4500-4600. I don't think a manifold or dump is going to help, my take on it was that a manifold actually caused the the turbo to spool a bit slower because the exhaust had to fill each runner equally, but produce better power.

[codyace]

The Disco Potato (GT28RS) does NOT make alot more power at the same 18-19psi. I had the DP in .86 trim, not the .64 Nyteryder is running with his 2871, and with an Enthalpy dyno tune, 740cc injectors, 3" turbo back exhaust I hit 315hp. This is using a turbo with a larger trim to get higher topend at the sacrifice of quick spool. I blew that turbo and upgraded to the GT2871R in .86 trim and it felt just a tad more powerful but nothing really exciting. Now, I threw in a set of cams the other day and THAT made a huge difference. I'll be installing my intake manifold and getting it retuned shortly and I expect to see around 400hp.

I disagree again, and have our dynos to prove otherwise

Big t28, with the largest A/R possible exhaust size, and normal to4b compressor (forget wheels)

16 psi, no cat, 3" exhaust, s3 cams, pulleys, light fylwheel...MSD 50 lbers, Cobra maf, JWT tune

FWD SR



And vs a b15...this time the b14 has a cat

Not sure why numbers are that well...i mean the compression should help a little, but the proof is on the paper ????

I'm just curious though, not trying to be a smart ***!!!

[BaliLover]

I disagree again, and have our dynos to prove otherwise

Big t28, with the largest A/R possible exhaust size, and normal to4b compressor (forget wheels)

16 psi, no cat, 3" exhaust, s3 cams, pulleys, light fylwheel...MSD 50 lbers, Cobra maf, JWT tune

Not sure why numbers are that well...i mean the compression should help a little, but the proof is on the paper ????

I'm just curious though, not trying to be a smart ***!!!

Cams man, they make a HUGE difference in an SR, and yes, a higher compression makes a difference too.

http://web.tampabay.rr.com/ent...i.jpg

312HP, 306TQ Thats a stock SR block and head, GT28RS .86 Disco Potato, Z32 MAFS, Tomei 740cc injectors, Greddy O2 extension and downpipe, Apexi N1 exhaust, Hybrid bar and plate FMIC, electric cooling fans, Walbro fuel pump.

http://web.tampabay.rr.com/ent...i.jpg

366.7hp, 297.2tq on pump gas with an SR with the GT2871r .64 trim and greddy 272 cams. Notice the run using C10 race fuel, 448hp.

http://web.tampabay.rr.com/ent...i.JPG

317hp, 313tq with a stock SR block and head, no cams, with the GT2871r .86 trim, about the same numbers as my dyno with the GT28RS in .86 trim.

Cams make all the difference in the world with most of these setups. Before I installed my cams with my GT2871R .86, it felt like it reached max boost at 4600 and stopped pulling, like it was outflowing the head. Once I installed the 264 step 1 cams, it feels more like it's pulling all the way to the top.

[codyace]

Awesome reply....i'm glad you actually realized I was curious as I really have never seen the difference

I wish I could see the dynos, however the forum is blocked by the air force net nanny we use on the army side of post here in kirkuk :/

Thanks agian though!!!

[jgauspohl]

so what do you guys think a fully built and ported blacktop head will pull w/ the .86 housing cuz I have one topmounted on a wasabi garage manifold....and it's brand new...might sell if it ..if I can't reach the hp I want. Oh yeah 8.5:1 pulleys..the works...should I sell it and get the ATP 3076?

[95lstegman]

when you say the .64 a/r GT2871R spools at 3500rpm, i'm assuming you mean full boost at 3500rpm? when does it break even to 0psi? where will it make 25%, 50% of set boost level? see what i mean? i'd REALLY appreciate a VERY detailed answer here. thanks in advance.

[BaliLover]

Ya know, I'm looking at this dyno again and just happened to notice how late the .64 is reaching max boost on your setup. my .86 reaches max boost at 4600-4800rpm and your .64 seems to be doing the exact same thing. Are you sure you aren't leaking exhaust before the turbo? Check where the manifold attached to the head, and where the turbo attaches to the manifold. The other thing you should check is that the wastegate is completely closed. I know you have to play around to hook the internal wastegate and solnoid to the GT2871 and if your arm is too long, the flapper will stay open and cause a late spool.

[D1 guy]

I have a .86 gt2871R and I see full boost by 4200....surely there is a bigger difference than 700rpm in the .60 and the .86. I thought you were supposed to see full boost around 3000rpm. Wow.

[BaliLover]

what is your full boost, because 4600 RPM seems to be common for 19psi but I see 10 much sooner than that.

[D1 guy]

1.3 bar

[95lstegman]

would somebody please give me a little info on the spool-up of this turbo with the .64 a/r turbine housing? like when it starts to make 0psi, when it makes 5psi, etc. i'd be really appreciative and it would only take a minute of your time, seeing as you drive it all the time anyways and you could just spout it off the top of your head. thanks in advance.

[BaliLover]

It and every BB turbo I've ever dealt with made 0psi as soon as you put the pedal to the floor

[95lstegman]

that's good i guess. when will it start to actually make boost?

[D1 guy]

as soon as you press the pedal down, you start making boost.....as with any turbo. anything over the 0 mark is making boost. I havent seen a turbo that stays in vac. with the pedal to the floor. Id hate to know that I had to wait 500 or 1000 rpm to get out of vac and into boost.

[95lstegman]

well, i mean with stock swap (well, just exhaust, koyo rad and SPAL fan), i get 0psi very easily as expected. and at around 2000rpm (i've never tried any lower) i can make about 1psi in upper gears where i can stay at 2000rpm for a second to find out. i can get about 4-5psi (so about 2/3 of full boost) at about 2500rpm and i can see full boost (7psi) at about 3100rpm. how does the .64 a/r GT2871R compare in these regards?

and BTW, thank you for the help you've given me so far. i have 0 experience with turbos other than the stocker. i like learning about cool stuff. (EDIT:<-- i was going to use a partially blanked curse word, but nico turned it into ****. lame!?)

[D1 guy]

Well, the .64 will be a lot like what youre used too, except its capable of more power. The .86 was the a/r for me b/c Im used to lag. the .86 has a very fast spool compared to the t04r on my supra that gets full boost at 6k. I dont know a whole lot about the .64, so I cant help you much there. I really like the .86 though

[95lstegman]

wow, if what you just said is true, i think you've just sold me on the 2871R. please somebody with a .64 a/r confirm this.