Originally Posted by Maxim_X

To be honest. I doubt that a gt28 will get you to 360 w/o 25+ psi. A 3076 is just about the perfect match for this car for a stock motor.

Originally Posted by Maxim_X

To be honest. I doubt that a gt28 will get you to 360 w/o 25+ psi. A 3076 is just about the perfect match for this car for a stock motor.

Originally Posted by selfinfliction

found some interesting info on garrett's website today comparing the gt2086rs, gt3076r, gt3582r and the gt3071r installed on a 2.0L motor:

http://www.turbobygarrett.com/turbob...o_tech103.html

We now have enough information to plot these operating points on the compressor map. First we will try a GT2860RS. This turbo has a 60mm, 60 trim compressor wheel.



Clearly this compressor is too small, as both points are positioned far to the right and beyond the compressor’s choke line.

Another potential candidate might be the GT3076R. This turbo has a 76mm, 56 trim compressor wheel:



This is much better; at least both points are on the map! Let’s look at each point in more detail.

For the 2.0L engine this point is in a very efficient area of the map, but since it is in the center of the map, there would be a concern that at a lower engine speeds that it would be near or over the surge line. This might be ok for a high-rpm-biased powerband that might be used on a racing application, but a street application would be better served by a different compressor.

For the 5.0L engine, this looks like a very good street-biased powerband, with the lower engine speeds passing through the highest efficiency zone on the map, and plenty of margin to stay clear of surge. One area of concern would be turbo overspeed when revving the engine past peak power. A larger compressor would place the operating point nearer to the center of the map and would give some additional benefit to a high-rpm-biased powerband. We’ll look at a larger compressor for the 5.0L after we figure out a good street match for the 2.0L engine.

So now lets look at a GT3071R, which uses a 71mm, 56 trim compressor wheel.



For the 2.0L engine, this is a much more mid-range-oriented compressor. The operating point is shifted a bit towards the choke side of the map and this provides additional surge margin. The lower engine speeds will now pass through the higher efficiency zones and give excellent performance and response.

For the 5.0L engine, the compressor is clearly too small and would not be considered.

Now that we have arrived at an acceptable compressor for the 2.0L engine, lets calculate a lower rpm point to put on the map to better get a feel for what the engine operating line will look like. We can calculate this using the following formula:

We’ll choose the engine speed at which we would expect to see peak torque, based on experience or an educated guess. In this case we’ll choose 5000rpm.

Where:

ˇ Wa = Airflowactual (lb/min)
ˇ MAP = Manifold Absolute Pressure (psia) =41.1 psia
ˇ R = Gas Constant = 639.6
ˇ Tm = Intake Manifold Temperature (degrees F) =130
ˇ VE = Volumetric Efficiency = 0.98
ˇ N = Engine speed (RPM) = 5000rpm
ˇ Vd = engine displacement (Cubic Inches, convert from liters to CI by multiplying by 61, ex. 2.0 liters * 61 = 122 CI)

= 32.5 lb/min

Plotting this on the GT3071R compressor map gives the following operating points.



This gives a good representation of the operating line at that boost level, which is well suited to this map. At engine speeds lower than 5000rpm the boost pressure will be lower, and the pressure ratio would be lower, to keep the compressor out of surge.

Originally Posted by SCcobaltSS

But I can see him getting the 30r and accomplishing 360WHP with only 260-280tq.. With the 28r he can wick the turbo up and gain some decent tq numbers out of that turbo and get to his HP goal.

I have seen people with your turbo do 440 whp and only have 330 tq. Same difference

Ok well I just realized you said stock motor. Cylinder pressure on 25psi on stock motor may spell disaster.

Originally Posted by selfinfliction

garrett says it's the 3071r

Originally Posted by Maxim_X

IMHO I think torque is basically a useless number. But, I put down about 360wtq.

I'd rather have that little bit of room if I want to turn it up. But, regardless they are both considerably better than the 28.

Originally Posted by ssyellow

http://www.youtube.com/user/black06g.../7/yuzbc1WCSmI

3076R. Dont know all the supporting mods on the car but it sure sounds nice.

Originally Posted by Maxim_X

To be honest. I doubt that a gt28 will get you to 360 w/o 25+ psi. A 3076 is just about the perfect match for this car for a stock motor.

Originally Posted by ~Mike~

I just want to get the car over 350 and close to 400. Kind of a personal goal I had before I even bought the car and was doing research on it and it's possible power upgrades.

Originally Posted by ssyellow

http://www.youtube.com/user/black06g.../7/yuzbc1WCSmI

3076R. Dont know all the supporting mods on the car but it sure sounds nice.

Originally Posted by USMCFieldMP

There is a member of this board that made 360whp with 16psi on a GT2871R





I've got a S256ET for sale @ $800... and I'm about to sell pretty much my entire set-up for $1500 (Minus the BOV and the Intake Manifold). You'd just need those two things plus figure out how you wanna run your Alternator set-up. My set-up would be good if you are looking for upper 300's/low 400's whp.

You can ask Tom about it feels... he tunes it.

Originally Posted by USMCFieldMP

There is a member of this board that made 360whp with 16psi on a GT2871R

Originally Posted by INFE

Yea that's my car