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turbotiger
05-14-2007, 01:58 PM
I thought it might be time to consolidate all the advantageous and disadvantageous of all the popular big turbos out there. I'm sure there's a link somewhere that discusses this, but I just can't seem to find it right now.

We'll start by discussing some of the popular ones we've seen dyno charts for here at norcalevo.
FP Green
50 trim
GT35

Points of discussion
1. What exactly is in the turbo. (Compressor housing and wheel, Exhaust housing and wheel, center cartridge).
2. What modifications are needed to bolt it on. (uses factory manifold & o2 housing, or requires custom parts or kit)
3. Approximate street price of new turbos / kit
4. What rpm does it spool up at 20psi.
5. Supports up to X HP

Forced Performance Evo Green (FP Green) / Buschur 20gLT

1. (from forced performance website)
The turbine housing is a 10.5cm2 nozzle housing and the compressor housing is the larger diffuser EVO9 casting. The 69mm 5blade CNC machined compressor wheel has a flow rating of 47lb/min and pressure ratio capability beyond 3.7:1 which allows for over 30psi boost pressure and RPM range beyond 8krpm.
The turbine wheel is larger in diameter than the stock TD05H.

So basically it's a standard thrust bearing stock center cartridge mated to a evo 9 compressor housing machined and fitted with a White Rabbit 5 blade compressor wheel. Turbine housing is a 10.5cm mitsubishi housing machined and mated to a larger turbine wheel.

2. Since it uses the mitsubushi housings, it bolts right into the stock manifold and o2 housing

3. Approximate price is $1,695

4. using GM boost solenoid, evo 8.
20psi @ 3600-3700 rpm
22psi @ 3900 rpm
24psi @ 4300 rpm

5. Supports up to ??? HP

50 Trim turbo
1. ?????
4. AMS 50 trim kit: using Apexi AVCR, evo 9
20psi @ 4000 rpm
25psi @ 4500 rpm

GT35 turbo
1. ?????

ATP GT3076
1. ?????
4. ATP GT3076 with tubular header: using Hallman MBC, evo 8
20psi @ 4200 rpm
23psi @ 4500 rpm

turbotiger
05-14-2007, 01:59 PM
Reserved

I need some more info on the 50 trim kits and GT35 series.
Anybody have any other suggestions on what other turbos or kits to look at?

earlyapex aka jack ass
05-14-2007, 02:26 PM
Here is some spool data.

My FP green: using GM boost solenoid, evo 8.

On the dyno in 3rd: (logged by dyno map sensor)
22psi: 39XX rpm (20psi at 37XX rpm)
24psi: 43XX rpm (20psi at 37XX rpm)
26psi: 43xx rpm (20psi at 36XX rpm)

On the street in 3rd: (logged by zeitronix map sensor)
27.5psi: 4159 rpm (not sure when 20 hits, will check logs)

AMS 50 trim kit: using Apexi AVCR, evo 9

On the dyno in 3rd:
25psi: 45XX rpm (20psi 4000 rpm)

ATP GT3076 with tubular header: using Hallman MBC, evo 8

On the dyno in 3rd:
23psi: 4500rpm (20psi at 4200 rpm)

spoolin
05-15-2007, 08:46 AM
A "comparable" alternative to the fpgreen would be the 20 G 9 turbo. A few ppl had these (drftr8 and ST) and have dyno results so you can look at spool time. It is comparable spool time to the green. It has a different wheel than the green tho, having six blades instead of five. You could throw that in your comparison. I believe it retails for 899 +shipping.

ST
05-15-2007, 09:34 AM
There are way too many derivatives of the GT30 variants...GT3071, GT3076, GT3037(variant of the 76), etc. not to mention you have to keep in mind the ARs of .63, .82., 1.X! for them as well as the "kit" that is sold (vishnus, atps, shearers, full race, ams, etc.). Then you also have the Evo 9 mivec spool ups on top of that which can change things tremendously.

In my view, here is the typical progression of turbo upgrades:

evo 8
evo 9
20g9-5/6 / white rabbit / tme's
fp green
gt3071 / 50 trims
gt3076/gt3037
gt35's

just do searches on evom, between all the clutter, there is a lot of good info.

ST
05-15-2007, 09:36 AM
ATP GT3076 with tubular header: using Hallman MBC, evo 8

On the dyno in 3rd:
23psi: 4500rpm (20psi at 4200 rpm)



Got a dyno sheet of this? I'm curious if the numbers and spool are consistent w/ evom reports.

earlyapex aka jack ass
05-15-2007, 11:00 AM
Got a dyno sheet of this? I'm curious if the numbers and spool are consistent w/ evom reports.


http://www.norcalmotorsports.org/users/bryan/mods/EVO/evo_tunes/ray_mygsx/041107/ray_boost_afr041107.jpg

It's not a typical ATP kit and has been customized (hence the tubular header)

ST
05-15-2007, 11:05 AM
Impressive spoolup for an evo 8 and the atp kit. i assume he has a .63 ar? are cam gears (if any) set for faster spool and the hotside ported?

earlyapex aka jack ass
05-15-2007, 11:12 AM
Not sure on AR. cam gears are +1/-1, everything is ported and matched. He put some TLC into it and it payed off. 345whp/292wtq on 91 octane.

ST
05-15-2007, 11:20 AM
Wait...isn't that Ray's (MYGSX's) dyno numbers? Correct me if I'm wrong, but it was reported as a GT3071s ATP kit before, not a 3076?

earlyapex aka jack ass
05-15-2007, 11:34 AM
Yes, Ray's. Not sure which one it is so I just put 3076, could be a 3071. All the numbers make baby jesus in my head cry.

O3EVO
05-15-2007, 12:12 PM
Great discussion here...

Bryan or ST, can you elighten me on the .AR stuff. What exactly does this mean and what does it do for the setup?

ST
05-15-2007, 12:16 PM
Great discussion here...

Bryan or ST, can you elighten me on the .AR stuff. What exactly does this mean and what does it do for the setup?


A/R (from Garret themselves):




A/R (Area/Radius) describes a geometric characteristic of all compressor and turbine housings. Technically, it is defined as:

the inlet (or, for compressor housings, the discharge) cross-sectional area divided by the radius from the turbo centerline to the centroid of that area (see Figure 2.).

The A/R parameter has different effects on the compressor and turbine performance, as outlined below.

Compressor A/R - Compressor performance is comparatively insensitive to changes in A/R. Larger A/R housings are sometimes used to optimize performance of low boost applications, and smaller A/R are used for high boost applications. However, as this influence of A/R on compressor performance is minor, there are not A/R options available for compressor housings.

Turbine A/R - Turbine performance is greatly affected by changing the A/R of the housing, as it is used to adjust the flow capacity of the turbine. Using a smaller A/R will increase the exhaust gas velocity into the turbine wheel. This provides increased turbine power at lower engine speeds, resulting in a quicker boost rise. However, a small A/R also causes the flow to enter the wheel more tangentially, which reduces the ultimate flow capacity of the turbine wheel. This will tend to increase exhaust backpressure and hence reduce the engine's ability to "breathe" effectively at high RPM, adversely affecting peak engine power.

Conversely, using a larger A/R will lower exhaust gas velocity, and delay boost rise. The flow in a larger A/R housing enters the wheel in a more radial fashion, increasing the wheel's effective flow capacity, resulting in lower backpressure and better power at higher engine speeds.

When deciding between A/R options, be realistic with the intended vehicle use and use the A/R to bias the performance toward the desired powerband characteristic.

Here's a simplistic look at comparing turbine housing geometry with different applications. By comparing different turbine housing A/R, it is often possible to determine the intended use of the system.

Imagine two 3.5L engines both using GT30R turbochargers. The only difference between the two engines is a different turbine housing A/R; otherwise the two engines are identical:
1. Engine #1 has turbine housing with an A/R of 0.63
2. Engine #2 has a turbine housing with an A/R of 1.06.

What can we infer about the intended use and the turbocharger matching for each engine?

Engine#1: This engine is using a smaller A/R turbine housing (0.63) thus biased more towards low-end torque and optimal boost response. Many would describe this as being more "fun" to drive on the street, as normal daily driving habits tend to favor transient response. However, at higher engine speeds, this smaller A/R housing will result in high backpressure, which can result in a loss of top end power. This type of engine performance is desirable for street applications where the low speed boost response and transient conditions are more important than top end power.

Engine #2: This engine is using a larger A/R turbine housing (1.06) and is biased towards peak horsepower, while sacrificing transient response and torque at very low engine speeds. The larger A/R turbine housing will continue to minimize backpressure at high rpm, to the benefit of engine peak power. On the other hand, this will also raise the engine speed at which the turbo can provide boost, increasing time to boost. The performance of Engine #2 is more desirable for racing applications than Engine #1 where the engine will be operating at high engine speeds most of the time.

http://www.turbobygarrett.com/turbobygarrett/images/tech_center/tech_102/enlarged_Images/compressor_housing_showing.gif


http://www.turbobygarrett.com/turbobygarrett/tech_center/turbo_tech102.html

typically the bigger the A/R, the higher the top end power...but usually at the expense of lag.

O3EVO
05-15-2007, 12:33 PM
^^ Damn, exactly what I was curious about.

Thanks to ST and Bryan for all of the above info...

turbotiger
05-17-2007, 01:51 PM
There are way too many derivatives of the GT30 variants...GT3071, GT3076, GT3037(variant of the 76), etc. not to mention you have to keep in mind the ARs of .63, .82., 1.X! for them as well as the "kit" that is sold (vishnus, atps, shearers, full race, ams, etc.). Then you also have the Evo 9 mivec spool ups on top of that which can change things tremendously.

What are the GT30 variants, and what makes them a variant?
Also, what is a 50 trim? Does that refer just to the compressor wheel size?
What's the difference between a Garett GT turbo and a non GT turbo? I noticed that the GT turbos are dual ball bearings, but you can get a non GT turbo in ball bearing too.

earlyapex aka jack ass
05-17-2007, 02:07 PM
The frame size of a turbo or CHRA is dictated by its turbine wheel inducer diameter . The larger the turbine inducer, the bigger the frame size-- so any turbo in the GT42 family has a larger turbine wheel inducer than those in the GT35 family, and so on.

In the model name of each turbo or CHRA, you'll also notice two digits after the frame size. These two digits refer to the compressor exducer diameter, as measured in millimeters.

Let's use the GT4294 as an example. This unit has a GT42 frame size turbine coupled to a 94mm (exducer diameter) compressor wheel.

If there's an "R" on the end of a model name, this means the unit is ball bearing. So, a GT4294 is not ball bearing; whereas a GT4294R is ball bearing.

A Guide To Garrett’s "GT" Model Numbers

GTxxyyzz:

* Positions "xx" refers to the frame size of the turbine wheel inducer.
o For example the "GT28" in "GT2860RS" refers to its turbine wheel frame size family. All GT28 units use a turbine wheel with 53.85mm inducer diameter
o As a rule of thumb, the larger the number, the larger the turbine wheel.
* Positions "yy" designate the compressor wheel exducer (major) diameter in millimeters
o The "60" in the GT2860RS example above has a 60mm compressor wheel exducer diameter.
o Note: Wheel sizes 100mm and over omit the "1" (hundreds digit)
o Example: the 02 in a GT4202 refers to its 102mm compressor wheel exducer diameter
* Positions "zz" may be used to designate special features of a particular turbocharger where applicable
o Example: GT2860RS
o "R" = this is a Ball Bearing unit
o "S" = used for units which require some differentiation from units in the same family
Compare a GT2860R to a GT2860RS. While both are ball bearing and externally similar, the GT2860RS is better suited for higher-flow applications than the GT2860R. In this case, the S reflects the higher-flowing nature of the GT2860RS

that's all copy pasted from garrett website btw, I'm actually not that smart. ;)

earlyapex aka jack ass
05-17-2007, 02:09 PM
and more...

1. Wheel trim topic coverage

Trim is a common term used when talking about or describing turbochargers. For example, you may hear someone say "I have a GT2871R ' 56 Trim ' turbocharger. What is 'Trim?' Trim is a term to express the relationship between the inducer* and exducer* of both turbine and compressor wheels. More accurately, it is an area ratio.

* The inducer diameter is defined as the diameter where the air enters the wheel, whereas the exducer diameter is defined as the diameter where the air exits the wheel.

Based on aerodynamics and air entry paths, the inducer for a compressor wheel is the smaller diameter. For turbine wheels, the inducer it is the larger diameter (see Figure 1.)

The A/R parameter has different effects on the compressor and turbine performance, as outlined below.

Compressor A/R - Compressor performance is comparatively insensitive to changes in A/R. Larger A/R housings are sometimes used to optimize performance of low boost applications, and smaller A/R are used for high boost applications. However, as this influence of A/R on compressor performance is minor, there are not A/R options available for compressor housings.

Turbine A/R - Turbine performance is greatly affected by changing the A/R of the housing, as it is used to adjust the flow capacity of the turbine. Using a smaller A/R will increase the exhaust gas velocity into the turbine wheel. This provides increased turbine power at lower engine speeds, resulting in a quicker boost rise. However, a small A/R also causes the flow to enter the wheel more tangentially, which reduces the ultimate flow capacity of the turbine wheel. This will tend to increase exhaust backpressure and hence reduce the engine's ability to "breathe" effectively at high RPM, adversely affecting peak engine power.

Conversely, using a larger A/R will lower exhaust gas velocity, and delay boost rise. The flow in a larger A/R housing enters the wheel in a more radial fashion, increasing the wheel's effective flow capacity, resulting in lower backpressure and better power at higher engine speeds.

When deciding between A/R options, be realistic with the intended vehicle use and use the A/R to bias the performance toward the desired powerband characteristic.

Here's a simplistic look at comparing turbine housing geometry with different applications. By comparing different turbine housing A/R, it is often possible to determine the intended use of the system.

Imagine two 3.5L engines both using GT30R turbochargers. The only difference between the two engines is a different turbine housing A/R; otherwise the two engines are identical:
1. Engine #1 has turbine housing with an A/R of 0.63
2. Engine #2 has a turbine housing with an A/R of 1.06.

What can we infer about the intended use and the turbocharger matching for each engine?

Engine#1: This engine is using a smaller A/R turbine housing (0.63) thus biased more towards low-end torque and optimal boost response. Many would describe this as being more "fun" to drive on the street, as normal daily driving habits tend to favor transient response. However, at higher engine speeds, this smaller A/R housing will result in high backpressure, which can result in a loss of top end power. This type of engine performance is desirable for street applications where the low speed boost response and transient conditions are more important than top end power.

Engine #2: This engine is using a larger A/R turbine housing (1.06) and is biased towards peak horsepower, while sacrificing transient response and torque at very low engine speeds. The larger A/R turbine housing will continue to minimize backpressure at high rpm, to the benefit of engine peak power. On the other hand, this will also raise the engine speed at which the turbo can provide boost, increasing time to boost. The performance of Engine #2 is more desirable for racing applications than Engine #1 where the engine will be operating at high engine speeds most of the time.

ST
05-17-2007, 02:09 PM
What are the GT30 variants, and what makes them a variant?

from Garret again (it's all on their website):



GT Basics / Nomenclature
Today, Garrett has a wider selection of GT-series turbos available than ever before. As a result of this, please note that we have made a subtle modification to the GT nomenclature.

In our product catalog, all offerings are grouped according to their turbine wheel frame size. The frame size of a turbo or CHRA is dictated by its turbine wheel inducer diameter . The larger the turbine inducer, the bigger the frame size-- so any turbo in the GT42 family has a larger turbine wheel inducer than those in the GT35 family, and so on.

In the model name of each turbo or CHRA, you'll also notice two digits after the frame size. These two digits refer to the compressor exducer diameter, as measured in millimeters.

Let's use the GT4294 as an example. This unit has a GT42 frame size turbine coupled to a 94mm (exducer diameter) compressor wheel.

If there's an "R" on the end of a model name, this means the unit is ball bearing. So, a GT4294 is not ball bearing; whereas a GT4294R is ball bearing.

The biggest change related to the nomenclature is this: units which utilize a 53mm turbine wheel (as measured at the inducer) are now referred to as "GT25" frame size, while units employing the slightly larger 53.85mm turbine wheel are now referred to as "GT28" frame size.

For those familiar with our product range, this means that the unit formerly known as "the GT28R" (part number 466541-1) is now in the GT25R family. More specifically, it is now a GT2560R model.

A Guide To Garrett’s "GT" Model Numbers

GTxxyyzz:

Positions "xx" refers to the frame size of the turbine wheel inducer.
For example the "GT28" in "GT2860RS" refers to its turbine wheel frame size family. All GT28 units use a turbine wheel with 53.85mm inducer diameter
As a rule of thumb, the larger the number, the larger the turbine wheel.
Positions "yy" designate the compressor wheel exducer (major) diameter in millimeters
The "60" in the GT2860RS example above has a 60mm compressor wheel exducer diameter.
Note: Wheel sizes 100mm and over omit the "1" (hundreds digit)
Example: the 02 in a GT4202 refers to its 102mm compressor wheel exducer diameter
Positions "zz" may be used to designate special features of a particular turbocharger where applicable
Example: GT2860RS
"R" = this is a Ball Bearing unit
"S" = used for units which require some differentiation from units in the same family
Compare a GT2860R to a GT2860RS. While both are ball bearing and externally similar, the GT2860RS is better suited for higher-flow applications than the GT2860R. In this case, the S reflects the higher-flowing nature of the GT2860RS


Some explanation on the different GT30 variants from ATP Turbo:



Some background on the above turbochargers:

The GT30R, GT3037S, GT35/40R and GT3071R are exceptional dual ball bearing turbochargers built by Garrett to cover a wide range of engine sizes and power ranges.

GT30R - A very popular name for a SERIES of Garrett ball bearing turbos, ranging from 350 HP all the way to 650 HP. Commonly mislabled as ONE particular turbo, but in fact there many wheel combinations built by Garrett referred to as "GT30R's". Many turbo selection errors have been made in the industry as a result of the wideness of the HP range in the GT30R family, ie. larger wheel combinations used in smaller engine (lower HP applications) resulting in poor spoolup. GT30Rs' are part of Garrett's earlier ball bearing line-up (consisting of about a dozen different wheel combinations) and are still very popular and reliable turbochargers, but because of its history of "misuse" and improper application matching and its lack of single identity, can no longer be used as the "benchmark" for comparison.

GT3037S - A particular variant of the GT30R family, but more commonly, another one of Garrett's ball bearing turbos found in a certain Japanese tuning company's turbo kit, popular for producing up to 500 HP. Commonly referred to as "the GT30R."

GT3071R - A brand new ball bearing turbocharger recently created by Garrett engineers to help fill the gap between smaller 300 HP turbos and the laggy GT3037S. The GT3071R is also one of the Garrett engineers' favorites because of its superior wheel match (between the compressor and the turbine wheel). A better wheel match means higher levels of efficiency. Higher levels of efficiency mean the turbo works less and achieves more and is happier and makes more power reliably. This is quickly becoming one of OUR favorites as well.

you should also look up the Garret Product map for them: http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT30/GT3071R.htm especially the compressor maps to understand its efficiency range.




Also, what is a 50 trim? Does that refer just to the compressor wheel size?


a good explanation: "The 50 in "50 trim" is just the trim of the compressor wheel. Trim is just a ratio of the inducer/exducer of a wheel. The inducer on the compressor side is 54mm. The turbo flows less than a 30R compressor but it's close. Some people have it rated from 46-49 lb/min. A 30R's compressor wheel flows 52 lb/min. A 35R compressor flows 65 lb/min." What that means usually is on pump gas, with all factors being the same, a 50 trim will do quite well equivalent to a gt30 on pump gas. once on race gas, with the better flow, the gt30 should outpower the 50 trim. ymmv depending on the kits though.

earlyapex aka jack ass
05-17-2007, 02:10 PM
And even more:

Acronyms / Terminology

A/R
A/R describes a geometric characteristic of all compressor and turbine housings. It is defined as the inlet cross-sectional area divided by the radius from the turbo centerline to the centroid of that area.

* Compressor A/R - Compressor performance is largely insensitive to changes in A/R, but generally larger A/R housings are used to optimize the performance for low boost applications, and smaller housings are used for high boost applications. Usually there are not A/R options available for compressor housings.
* Turbine A/R - Turbine performance is greatly affected by changing the A/R of the housing. Turbine A/R is used to adjust the flow capacity of the turbine. Using a smaller A/R will increase the exhaust gas velocity into the turbine wheel, causing the wheel to spin faster at lower engine RPMs giving a quicker boost rise. This will also tend to increase exhaust backpressure and reduce the max power at high RPM. Conversely, using a larger A/R will lower exhaust gas velocity, and delay boost rise, but the lower backpressure will give better high RPM power. When deciding between A/R options, be realistic with the intended vehicle use and use the A/R to bias the performance toward the desired powerband.

Choke Line
The choke line is on the right hand side of a compressor map and represents the flow limit. Properly sizing a turbo is important to prevent the compressor from operating past the choke line. When a turbocharger is run deep into choke, turbo speeds increase dramatically while compressor efficiency plunges (very high compressor outlet temps). Additionally, the turbo's durability is compromised by the resulting high thrust loads.

CHRA
(Center Housing & Rotating Assembly)
The CHRA is essentially a turbocharger minus the compressor and turbine housings

Clipped Turbine Wheel
When an angle is machined on the turbine wheel exducer (outlet side), the wheel is said to be "clipped". Clipping causes a minor increase in the wheel's flow capability; however, it dramatically lowers the turbo efficiency. This reduction in efficiency causes the turbo to come up on boost at a later engine speed (ex. increased turbo lag). High performance applications should never use a clipped turbine wheel. All Garrett GT turbos use modern unclipped turbine wheels.

Corrected Air Flow
When plotting actual airflow data on a compressor map, the flow must be corrected to account for different atmospheric conditions that affect air density.
Example:
Air Temperature (Air Temp) - 60°F
Barometric Pressure (Baro) - 14.7 psi
Engine air consumption (Actual Flow) = 50 lb/min
Corrected Flow= Actual Flow SQR([Air Temp+460]/545)/ Baro/13.95
Corrected Flow= 50*SQR([60+460]/545)/ 14.7/13.95 = 46.3 lb/min

Efficiency Contours
The efficiency contours depict the regional efficiency of the compressor stage. When sizing a turbo, it is important to maintain the proposed lugline with a high efficiency range on the map.

Free-Float
A free-floating turbocharger has no Wastegates device. This turbocharger can't control its own boost levels. For performance applications, the user normally must install an external Wastegates.

GT
The GT designation refers to Garrett's state-of-the-art turbocharger line. GT-series turbos use redesigned bearing systems and modern compressor/turbine aerodynamics. These new compressor and turbine wheels represent huge efficiency improvements over the old T2, T3, T3/T4, T04 products. The net result is increased durability, higher boost, and more engine power over the older T-series product line.

On-Center Turbine Housings
On-center turbine housings refer to an outdated style of turbine housing with a centered turbine inlet pad. The inlet pad is centered on the turbo's axis of rotation instead of being tangentially located. Using an on-center housing will significantly lower the turbine's efficiency. This results in increased turbo lag, more backpressure, lower engine volumetric efficiency, and less overall engine power. No Garrett OEM's use on-center housings.

Pressure Ratio
Ratio of absolute outlet pressure divided by absolute inlet pressure
Example:
Intake manifold pressure (Boost) = 12 psi
Pressure drop, intercooler (DPIntercooler) = 2 psi
Pressure drop, air filter (DPAir Filter) = 0.5 psi
Atmosphere (Atmos) = 14.7 psi at sea level
PR = (Boost + DPIntercooler+ Atmos) / (Atmos-DPAir Filter)
PR = (12 + 2 + 14.7) / (14.7 -.5) = 2.02

Surge Line
The surge region, located on the left-hand side of the compressor map, is an area of flow instability typically caused by compressor inducer stall. The turbo should be sized so that the engine does not operate in the surge range. When turbochargers operate in surge for long periods of time, bearing failures may occur.

Trim
Trim is an area ratio used to describe both turbine and compressor wheels. Trim is calculated using the inducer and exducer diameters.
Example:
Inducer diameter = 88mm
Exducer diameter = 117.5mm
Trim = Inducer2/Exducer2
Trim = 882/117.52 = 56 Trim
As trim is increased, the wheel can support more air/gas flow.

Wastegates
A Wastegated turbocharger includes an integral device to limit turbo boost. This consists of a pneumatic actuator connected to a valve assembly mounted inside the turbine housing. By connecting the pneumatic actuator to boost pressure, the turbo is able to limit its maximum boost output. The net result is increased durability, quicker time to boost, and adjustability of boost.

crctslt
05-17-2007, 02:45 PM
Points of clarification:

ATP's site is a little misleading as quoted in ST's post above. I find it interesting that they call the 3037 laggy. It isn't.

The Garrett 3076R and the HK$ 3037S are the exact same CHRA and compressor cover. The only difference between them is the turbine housing itself. The 3037S uses a HK$ turbine housing that uses a rectangular T-25 inlet with (most commonly) a .73 A/R. The 3076R uses a T-3 turbine housing with (most commonly) a .63 A/R.

As far a 50 trims. The 50 trim turbo is a 1970's design. The 3076R is a 1990's design. I like to think that Garrett learned a few things in ~20 years. The 3076 is more efficient. I agree with ST in that I have seen flow ratings of ~49 lbs/min for the 50 trim and 52lbs/min on the 3076R. However it is fairly well known that the 52 lbs/min rating on the 3076R is pessimistic. Cars with that turbo regualrly put down over 500whp on Dynojet 248C's.

What I would be very interested in is trying to figure out is why it seems that EVO's seem to spool they're turbo's slower that DSM's. I was under the impression that the EVO drivetrain has evolved from it's DSM counterparts. I would really like to find out what the differences are and why they made the change.

As I have posted before here are some numbers from my 2g Eclipse.


FP3052 turbo (bolt on 3076R for DSM's with .70 A/R)
On my Stock bottom end 2g DSM (8.5:1)
1g head with HK$ 264i/272e and 1mm over intake and exhaust valves
Stock 1g intake manifold
ported Evo 3 exhaust manifold
Greddy Profec-B boost controller set to full gain

20 psi @ 3750 rpm

25 psi @ 3950 rpm

PANGES
05-17-2007, 02:52 PM
that's all copy pasted from garrett website btw, I'm actually not that smart. ;)


hehe. When I started reading your post, I was like "damn, Bryan really knows his shit.." Then I got to the bottom and now we all know better. :lol:


hehe jk. We know you still know your shit :D

ST
05-17-2007, 02:59 PM
great info and clarification, crctslt - i think it was a lot of marketing fluff to sell the new gt3071 variant, however on evos (i cannot speak for the descrepency between it and dsms), typical spool times of gt3076r/gt3037s have been around the 4500rpm range. the smaller gt3071 was supposed to pushed it down to the more street-friendly 4100 rpm range at the expense of all out hp. hence, why they probably termed it "laggy".

EFIxMR
05-17-2007, 03:56 PM
IMHO the 50 trim BB is a better turbo than both the 3052R and 3071R.

One of the first GT3052R's I did with Casey was the Forced Fed MR, that car was tuned very aggressive and had huge camshafts and on C16 only pushed out 405 whp on the GS dyno.

From my testing on the 50 trim BB, and from Bryans results the 50 trim BB pushes over 400+ whp easily and has what I see as the best spool between the three turbos.

crctslt
05-17-2007, 06:07 PM
IMHO the 50 trim BB is a better turbo than both the 3052R and 3071R.

One of the first GT3052R's I did with Casey was the Forced Fed MR, that car was tuned very aggressive and had huge camshafts and on C16 only pushed out 405 whp on the GS dyno.

From my testing on the 50 trim BB, and from Bryans results the 50 trim BB pushes over 400+ whp easily and has what I see as the best spool between the three turbos.


Andy if you can talk about it can you elaborate more on the ForcedFed MR? I cant find my SCC issue it was in at the moment. What was done to the following:

Intake manifold
Cams
Intake and exhaust valves
Head porting
Compression ratio
Exhaust manifold

I'm just trying to figure out the variances.

EFIxMR
05-17-2007, 06:14 PM
Stock MR 05'

Revolver Cams and valvetrain

880 injectors

FFed kit 3052 aka 3076 BB (the 3076 actually can refer to a bunch of different gt30 variants the "76" refers to the exducer or outer diameter)

Spearco FMIC

Autronic ECU

Twin plate Exedy

other than that it was all stock everything else

crctslt
05-17-2007, 06:24 PM
Thanks Andy :D

mygsx
05-21-2007, 09:56 AM
hi ST, yes i've got a 3071 it no way spools in third gear full boost by 4k its more like 4500-5k rpm's. I think it could be attributed to my cg's also being set @ -2/-2. If i swap out my header for say a ported manifold it may help in spool but unsure how much more :D

ST
05-21-2007, 10:02 AM
hi ST, yes i've got a 3071 it no way spools in third gear full boost by 4k its more like 4500-5k rpm's. I think it could be attributed to my cg's also being set @ -2/-2. If i swap out my header for say a ported manifold it may help in spool but unsure how much more :D


good info! i think the atp kits have been traditionally a little laggier due to the custom hotside made, at least according to owners.

mygsx
05-21-2007, 10:09 AM
the previous owner of this kit -jbfoco had a ported stocker header with this kit and he said he had full spool by 4k without cg's so probably my header in combination with the retarded cg settings are what is making this spool just absolutely horrible =X

jbfoco
05-21-2007, 04:43 PM
I had ported stock manifold with gsc 272/272, dont remember the gear settings. 20psi 4th grear at 4k

UCB
05-29-2007, 12:22 AM
Stock MR 05'

Revolver Cams and valvetrain

880 injectors

FFed kit 3052 aka 3076 BB (the 3076 actually can refer to a bunch of different gt30 variants the "76" refers to the exducer or outer diameter)

Spearco FMIC

Autronic ECU

Twin plate Exedy

other than that it was all stock everything else


evoM folks will tell you that you're missing HP due to the revolver cams, lol

turbotiger
05-29-2007, 02:01 PM
evoM folks will tell you that you're missing HP due to the revolver cams, lol

Thankfully this is not evoM.