mau

I just got this setup installed in a performance place in which consists of a A3 manifold, Garrett T04 E40/STG2 .48, external wastegate w/ .8 bar spring (Tial), Turbo Xs BOV and some other little things (hoses, etc...)I'VE HAD a tap stage 2 chip 12.5 lbs, an HKS mega flow intake, hks exhaust, no cat, turbo back 2.5". With the new turbo,THE CAR IS A COW!!! Well, I have no bottom end at all. The car begins to pull at around 5 grand. There is no boost until around those rpms. I'm waiting for injectors and a custom chip. Is this what I'm missing for this setup to run strong? Why is there SO MUCH lag? Is it the wrong setup? I feel like I wasted my money. Any help would be greatly appreciated!!
ps. The other thing that caught my eye was the 90 degree turn they made from the air intake to the turbo. Any comments on that would be great.

Thanks
Mau

snoogins

Calm down...wait for the injectors and chip...repost your results. They will make a difference. If they don't, then you have a problem.

SpenceSTL

I would venture to guess that it would be impossible to make any solid conclusions until you have your injectors and your ECU is properly tuned. The stock injectors are woefully small for your setup, as a full blown T04 should be good for between 300-450 or so HP depending on compressor wheel. I would be very careful about thrashing the car too hard until then, as leaning out could become a problem really fast with that type of turbo. Another thing to consider though, is that a T4 is a very big turbo for your App, and I wouldn't expect a whole lot of bottom end boost. I am planning a T3/T4 Ball Bearing Hybrid, but am holding off until either one of the tuners comes out with a solid Chip for this setup, or I come up with a good alternative for ECU tuning. On a 4 cylinder, with a 5 bar F.P.R., you are still looking at needing somewhere in the neighborhood of a 7-800cc injector to push 400Hp safely. No tuner that I have seen has used an injector this big yet on the 1.8T

Oh well, until then

xr4tic

550cc/m is more than enough. Good luck trying to get an 800cc/m injector to idle.

Go here: <a href="http://www.rceng.com/technical.htm">Injector sizing</a>

Mike O.

...if you have a T04E hot side (turbine).

Put a .48 T4 turbine housing next to a .40 T3 housing and you'll be amazed at the difference in size. The T04E turbine is rated for 500+hp but you need some serious cubic inches to get it to spool - or some serious RPMs in a small motor.

Dump the T4 hotside and get a T3 and you'll love it.

Mike O.

P.S. The T04 turbine is used on big block V8s and Banks diesel conversion kits - it's way too much for a 100c.i. engine!

mau

big setup regardless what injector and chip I put on it? I know I'm not gonna have a bottom end like a small turbo (K03 for example), but adding a FMIC, larger injectors and a chip might help with bottom end?

Thanks
Mau

xr4tic

Check out this compressor flow map for a T04E "40"

<img src="http://pictureposter.audiworld.com/12130/toobig.jpg">
These are the general assumptions I made:
Temp = 60F, outside air press = 14.7, volumetric efficiency = 90%, inlet pressure drop = 0.75psi, intake pressure drop = 1psi.

Point 1: boost onset - 3000 RPM, 2 psi of boost.
6.83 lb/min @ 1.18 pressure ratio
Point 2: point of max boost - 4000 RPM, 20 psi of boost
18.92 lb/min @ 2.53 pressure ratio
Point 3: red line - 6500 RPM, 20 psi
30.75 lb/min @ 2.53 pressure ratio

See how point 2 is past the surge line? That's bad, mmkay.
It's not until about 5000 RPM that the turbo starts working like it should.

This turbo is just too big for a 1.8L motor. Higher boost will shift the numbers up and to the right, lower boost will shift them down and left.
Higher intake temps will shift the numbers down (only slightly though)

Check out this link, and plug in some numbers, to find a suitable turbo for your needs:
<a href="http://www.turbofast.com.au/turbomap.html">http://www.turbofast.com.au/turbomap.html</a>

Mike O.

...but it is the hot side (turbine) that makes the difference in spool up (turbo lag).

Call someone like Turbonetics to see if you have the option of swapping the T4 turbine for a T3 turbine in the same .48 A/R. The T3/T04E in .48/.60 A/Rs will spool at the same rate as the APR Stage 3 (according to the guys that sell APR their GT25s).

There is nothing short of NOX that will increase energy flow enough at lower RPMs to make a difference.

Sorry,
Mike O.

PanTTher

You need to use the same reference temperature and pressure the manufacturer uses to generate the map for your calculations. Without the reference numbers your superimposed points will be off (maybe turbo calc takes that into account, not sure). I'll have to refer back to my notes, which I don't have handy right now, but I think Garrett uses 80F or 85F and 14.3psia as reference figures.

Volumetric efficiency for turbo engines is a variable and it is above 1 past a certain rpm. Vol. Eff. is the ratio of the actual volume of air ingested by the engine divided by the engine displacement. A 1.8T engine with a K04 turbo flows about as much air as a normally aspirated small block V8 at some point in the rev band.

xr4tic

I did take the inlet prssure into consideration, and changing the intake temp, will only drop the mass readings slighly.

As for Volumetric Efficiency, you look at it from a NA standpoint. The flow path will have restrictions, even under boost conditions, and this is where VE comes into play.

So the corrected points are:

Temp = 85F, outside air press = 14.7, volumetric efficiency = 90%, inlet pressure drop = 0.75psi, intake pressure drop = 1psi.

Point 1: boost onset - 3000 RPM, 2 psi of boost.
6.67 lb/min @ 1.17 pressure ratio
Point 2: point of max boost - 4000 RPM, 20 psi of boost
18.48 lb/min @ 2.43 pressure ratio
Point 3: red line - 6500 RPM, 20 psi
30.04 lb/min @ 2.43 pressure ratio

As you see, little has changed.