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Old 03-26-2011, 01:22 PM   #1
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Default Low power from new turbo, less then my 2560?

Hey guys, I had a few questions as to what could be causing my issues with power after my turbo swap. Since my build I have not been able to get very far over the 200rwhp mark, I believe 220 was my cap. Right now I am running the Begi China 2871 (swapped in last summer), with my boost set at 12psi, which should as far as I can tell put out more power then 15 on a gt2560.

The issue is, I'm just not seeing it. I am making the boost, no issue. The issue is I just don't see the power. I will be doing a leakdown test just to put my mind at ease, but was wondering what could be causing the issues I am having. I know my exhaust is on the smaller side, but 2 3/8" should not be causing this huge of a performance loss, right?

My thoughts;

-Bad leakdown on one or more cylinders?
-Weak spark from coils? I have a pair off a 95 with 50k on them I will be swapping.. I've been debating COPs but I have no idea how to set them up..
-Bad tune? I will be checking my 0 on the hydra when I get home tonight, while I warm the car up for the leakdown.
-IC is too small? I'm using the stock IC from the FM2..

At this point I am at a loss, and since the roads have (lots of) salt on them yet, I can't take it out and do some field tests yet, either.


Stats;

FM2 w/ Hydra and Chinacharger 2871
Forged bottom end, rods and pistons
NB head (99), vics is active via hydra
Racing Beat exhaust (2.375"), eventually will be a full 3"
FM race pipe, cat eliminated
Walbro 190

Last edited by Der_Idiot; 03-26-2011 at 03:14 PM.
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Old 03-26-2011, 01:56 PM   #2
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I bet it has something to do with the unknown turbine and compressor shape rather than size and trim.

edi:
Pics of bottom end?
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Old 03-26-2011, 02:00 PM   #3
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Here's the Turbo in question;

http://www.bellengineering.net/produ...roducts_id=404

Code:
Compressor Specs :
             1.70" Compressor Inlet
             1.685" or 42.81mm inducer
             2.362" or 60.00mm Major
             Compressor .80 A.R.
              M24 T2 Compressor Housing 
Turbine Specs :
              1.850" Exducer
              Turbine .86 A.R.
              2.090" or 53.10mm Major
              1.820" or 46.25mm Minor
As for pics, I don't have any presently. My friend built his almost the exact same except his has a larger IC, NA head and a 2860RS. I'm almost certain the A/R is .6, not .8 but I have to look for the receipt.
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Old 03-26-2011, 02:46 PM   #4
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Ok, 1st of all: do you have a dyno plot of each setup? Cause "butt dyno" doesn't tell us jack ****.
2nd of all: just because its physically larger doesn't mean "this turbo should put down same power at lower psi than the other" As stated before physical difference makes them completely different.

I've noticed many chinachargers build torque more linearly/smoother than brand name turbo's, so you very well may be making same or more power, but not feel as fast due to it not coming on as violently. just my .02
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Old 03-26-2011, 03:11 PM   #5
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Thanks for the feedback, I haven't touched the car in 7 months because it was breaking my wallet and my will heh. But I got a killer deal on some bushings and endlinks and the warming weather fired up my desire to get this thing finished.

Yeah I do have a few dyno sheets (at home, lol). I will try to get PDF copies off the guy that did my tuning with the 2560. I need to get an updated dyno with the 2871, but I did use the street dyno with the hydra, dumped it into the log viewer from FM and output a chart that showed very similar (and in some cases, loss) of power.

As for your second point, I kinda figured that. I looked at the measurements for this and had Begi mod the inlet to suit my FM silicone hose and get everything bolted up, but beyond that it should be the same measurements as shown above.

I also don't have a lot of faith in my tuner, he's a good guy but I've heard a lot of grief about this guy, and noone else local can tune a hydra (or is willing to). I go through Chicago and near Detroit regularly, is there a reliable shop that can tone these things? lol
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Old 03-26-2011, 03:21 PM   #6
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there are tons of tuners in Chicago. P&L can tune damn near anything, AMS if you have the money.
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Old 03-26-2011, 03:30 PM   #7
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Quote:
Originally Posted by Aricjm15 View Post
there are tons of tuners in Chicago. P&L can tune damn near anything, AMS if you have the money.
You have my thanks, I'm tired of these shady guys up here. It seems if it aint a Suby or a Honduh they just don't give a damn.

I guess I'll swap my coils off the stock motor, run a leakdown test and double check the 0 timing and see how she runs. I'll try running .028 gap and check my map, I think the last time I ran a test I was running in the mid to low 10's under WoT. Could probably stand to lean out the map some...
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Old 03-26-2011, 03:43 PM   #8
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Multiple chinacharger users have shown that they can't be compared to the genuine turbos. I am in this group. With my new map sensor I'll be boosting my china 2871 to 25 psi. I think I'll be lucky to make 320HP at the wheels.
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Old 03-26-2011, 03:45 PM   #9
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Oh, if that's the case I will be a very sad panda. If I can't push 300 I'll just sell my 2560 and 2871 and pickup a GT30. May as well go big if I have big aspirations, no?
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Old 03-26-2011, 03:49 PM   #10
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search around the forum a bit. I think there are soem better options than the GT30. May want to look into one of the Borg warner turbos.
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Old 03-26-2011, 03:56 PM   #11
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love my godspeed 3076
if you don't have the cash for awesome stuff (like bw) then I'd look into that.
I hit just over 300 on 16psi which IMO is not bad and feels great
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Old 03-26-2011, 04:03 PM   #12
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Seeing as how your "2871" has a 60mm comp exducer (like your 2560 has) and churbos consistently show less power than genuine units, combined with your coffee straw exhaust, I'm not at all surprised to see a loss in power going from a genuine 2560 to a chinese "2860".

I don't have turbine sizes memorized, someone tell me/him how close that china turbine wheel is to the 25/28 wheel sizes.
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Old 03-26-2011, 04:09 PM   #13
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What did you shell out for that? I just might consider it, but I'm also about ready to throw myself to the wind and get the FM 3" exhaust, after that it's just a matter of watching my injector duty, maybe upsize to 750 if I need to down the road. But first things first, my goal of 300. lol
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Old 03-26-2011, 04:14 PM   #14
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Quote:
Originally Posted by 18psi View Post
love my godspeed 3076
if you don't have the cash for awesome stuff (like bw) then I'd look into that.
I hit just over 300 on 16psi which IMO is not bad and feels great
What does your spool look like on that turbo? If I'm running on the highway at 3800rpm in 5th (6spd) my logs show that I go from 0-20psi in ~ 1s spooled by 4300 rpm. I'm going to pull my manifold and send it to ArTech for some modifications. I might just get the larger chinaturbo at the same time.
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Old 03-26-2011, 04:43 PM   #15
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Don't be the idiot, here, op. :P

Buy less stuff.

What you do buy, buy it right.

A 2560 can make over 300whp on an optimized setup. Churbos... well. A Garrett 3076 is a 530whp turbo. A Garrett 2871 is a 400whp+ turbo.

Have you seen the churbo dyno plots? Torque comes on like a 70 degree angle on some of them.

Stop adding things. Start replacing junk and doing it right.
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Old 03-26-2011, 05:14 PM   #16
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Yeah I know. I've just worked myself into a corner somewhat, and nobody of any worth is available locally. They've all either moved out, or work 80 hour weeks.

So, what would you suggest I replace or fix first? I was thinking the exhaust could be a hindrance, but it could also be the tune. Hard to say at this point.
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Old 03-26-2011, 05:20 PM   #17
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Quote:
Originally Posted by djp0623 View Post
What does your spool look like on that turbo? If I'm running on the highway at 3800rpm in 5th (6spd) my logs show that I go from 0-20psi in ~ 1s spooled by 4300 rpm. I'm going to pull my manifold and send it to ArTech for some modifications. I might just get the larger chinaturbo at the same time.
Old *** log with less boost than I'm running now. 4th gear (5sp)


From 3k and up the car has some GOOD smooth torque and feels good. at 4k its starting to wake up. at 4500 its hauling ***
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Old 03-26-2011, 05:34 PM   #18
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Step one:

Stop depending on others when you can't.

Bad spark shouldn't be an issue at your boost levels, but Trackspeed makes a plug and play COP setup.

Hydra... I suggest learning to tune it yourself, but no idea how with that thing. Sell it off and get a Megasquirt, honestly, is what I'd say. Tunerstudio is AMAZING.

Basicly, learn to take care of yourself. Do your own tune. If you're depending on others, you'll be screwed no matter what.

Your chinacharger is going to be worse than the 2560, most likely. Learn to tune, put the 2560 back on. 15psi on a 2560 should put you closer to 260whp once you get a real exhaust and tune. Sell off the hydra, your current exhaust, your chinacharger, get decent stuff you can use. Get a decent exhaust, ramp up the 2560 to 18psi, and you'll be near your goal with awesome spool.

But the best part?

You'll be able to do it yourself.
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Old 03-27-2011, 02:28 AM   #19
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Quote:
Originally Posted by Der_Idiot View Post
That's a 2860 clone. Definitely not a 2871R clone. 60mm compressor exducer.

Garrett GT2860RS specs:
47.2mm inducer
60.1mm exducer (comp)
53.0mm "Major" (inducer)
41.9mm "Minor" (exducer)


Garrett GT2871R specs:
51.2mm inducer
71.0mm exducer (comp)
53.9mm inducer (turbine)
47mm exducer

I'm not even slightly surprised that a Chinese "2860" clone is getting outperformed by a genuine Garrett 2560R.

Sell the "2860", put the 2560R on it, and get it tuned correctly.
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Old 03-27-2011, 02:50 AM   #20
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you need to run more boost.
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