Turbo final decision ( trust me, I've searched)

[teqnick]

Currently finishing up my KA-T build,

Isis v2 bottom mount
SARD 850cc side feed
Isis fmic
Enthalpy rom tune for 93 octane
Tomei fpr
255lph fuel pump
Greddy BOV
Greddy profec spec b

Stuck between either a gt2871r, or the gtx2867. After I build the block ( CP 9:1, Manley h beam rods) , my goals are to push 375 at the wheels . The car will be used primarily for drift events.

Is it worth it to go with the gtx and allow myself more headroom if I decide I want more power? I'm fine with boost coming on a couple hundred rpm later. I just can't come to the conclusion whether or not it's worth the extra $.


Sent from my iPhone using Tapatalk

[PoorMans180SX]

Ditch the Garrett idea and get an EFR 6758. Outperforms both of them.

[teqnick]

Definitely would consider it if I didn't already have a line on both of these Garretts in gently used condition. Anyone else?

Much appreciated


Sent from my iPhone using Tapatalk

[Dboyizmlg]

If you want more power down the road, them consider the 2871r.

I would personally go with the GTX 2867, just because I love the faster spool, and quick response. Also, what fuel are you tuning with?
I suggest E85; if it's available to you, go that route!!!

You will be very happy

[teqnick]

I guess what I'm truly looking for is the perfect balance between spool and response , vs. a strong top end and gobs of power . I know I'll have to make a sacrifice at some point. E85 is available here in chicago, but I won't be initially tuning for it. 93 octane for now. I'm leaning towards the 2871 as well because of the power I'll have at higher rpm's for when I'm drifting . The 4mm difference just might be night and day for me


Sent from my iPhone using Tapatalk

[Dboyizmlg]

I guess what I'm truly looking for is the perfect balance between spool and response , vs. a strong top end and gobs of power . I know I'll have to make a sacrifice at some point. E85 is available here in chicago, but I won't be initially tuning for it. 93 octane for now. I'm leaning towards the 2871 as well because of the power I'll have at higher rpm's for when I'm drifting . The 4mm difference just might be night and day for me


Sent from my iPhone using Tapatalk

I have 2871r .64 A/R,
tuned on E85 fuel, at 17 psi, with tomei 256 cams, every thing else is stock.
Motor made 370whp @17 psi.
Its a bit laggy for me, full boost is around 4,200 rpm. Has nice mid power, to top end.

But I miss my T28, because I had full boost around 3,800 rpm.
I think that GTX2867 will be similar response to T28, but with much better mid-top end power.

The transient response is much more fun to me! I like TQ as mush as hp. So in my opinion the GTX is a better bang for you buck!

BTW, just go E85!

[PoorMans180SX]

You want the GTX2867 over the GT2871R for sure.

http://ec1.gorytus.datumweb.com/1/calibra460.jpg

http://i473.photobucket.com/albums/rr97/smithboy76908/GTX2867R_OverlayofGT2871and76R.jpg~original

[teqnick]

It looks like the 2867 is making 20ish more whp at its peak, which is nice . And after 3650 it just takes off in terms of performance. 500 dollars better?


Sent from my iPhone using Tapatalk

[R3cK]

as a chart noob: the EFR6758 looks beast. holy crap

[Kingtal0n]

as a chart noob: the EFR6758 looks beast. holy crap

something about the chart is funny. 400 horsepower at 3000rpm? 700 ft lbs of torque is coming out of the engine at 3000rpm? Clearly something is being lost in translation, such as, that is not an SR20 Engine.

[PoorMans180SX]

something about the chart is funny. 400 horsepower at 3000rpm? 700 ft lbs of torque is coming out of the engine at 3000rpm? Clearly something is being lost in translation, such as, that is not an SR20 Engine.


Here we go again. Who gives what engine it is if it is a direct comparison of turbos. Secondly, there is no 700ft/lbs of torque, nor 400hp at 3000rpm. You're reading the graph wrong.

The hp and tq numbers don't cross at 5250, so they're scaled differently, or torque is in Nm.

[Kingtal0n]

Here we go again. Who gives what engine it is if it is a direct comparison of turbos. Secondly, there is no 700ft/lbs of torque, nor 400hp at 3000rpm. You're reading the graph wrong.

The hp and tq numbers don't cross at 5250, so they're scaled differently, or torque is in Nm.


The graph clearly says "corrected horsepower engine number" So all of those lines should be horsepower (but I see now, they are not).

And if you think displacement has nothing to do with the action of a turbocharger... well. it does.

In any case, I dont see any units or engine details... which makes it difficult to use as information. Furthermore, it says "corrected" which means there was some computation on the part of the computer that alters to the lines to "what the computer thinks the engine is really producing".

[PoorMans180SX]

The graph clearly says "corrected horsepower engine number" So all of those lines are HORSEPOWER there are no TORQUE lines.



And if you think displacement has nothing to do with the action of a turbocharger...


Errrr wrong. The lines are labled "CEngHp" and "CEngTq"...

Not sure where you got 700 anyway, it's not even on the y-axis...

[PoorMans180SX]

The graph clearly says "corrected horsepower engine number" So all of those lines should be horsepower (but I see now, they are not).

And if you think displacement has nothing to do with the action of a turbocharger... well. it does.

In any case, I dont see any units or engine details... which makes it difficult to use as information. Furthermore, it says "corrected" which means there was some computation on the part of the computer that alters to the lines to "what the computer thinks the engine is really producing".

Turbocharger performance is directly relative to what engine it is attached to, yes. Given a direct comparison such as the one above, it's pretty easy to extrapolate the data onto whatever engine you have (with relative accuracy), especially when it's obviously also something with 1.8-2.2 liters of displacement.

Data is data is data. As long as the variables are controlled, data is accurate. Every single dyno number is "corrected" in some way or another. A dyno is essentially a computer taking a couple measurements of force and making a computation from it.

[teqnick]

I'm no genius at reading these graphs , but I don't even see where those #s came from... Anyhow,

It looks like just for response sake, the GTX is the way to go. I dug a bit deeper and found a test from Martin @ enthalpy swearing by the 2867 a few years back, coming from a 2871. I think I've made my choice .

[RalliartRsX]

Poormans, as a huge proponent of the EFR turbo line (I currently have a 6258 and a 6758), that graph is devoid of a fair amount of information (no engine size, dyno conditions on each pull, engine size, exhaust, the list goes on) and cannot be used to draw any viable conclusion.

I actually found that graph when I did my search before installing my own EFR and immediately had to ignore it for the very reasons above.

Also, for the individual who states the GTX spools faster, that is not true. The basses behind the GTX line is simply flowing more for a given boost, meaning; 10 psi on a GT2871R makes x amount of power and 10psi on a GTX of the same variety flows several lbs more at the same 10psi boost level. If you would like a graph of a GT3071R vs a GTX3071R, I will gladly post it.

[PoorMans180SX]

Poormans, as a huge proponent of the EFR turbo line (I currently have a 6258 and a 6758), that graph is devoid of a fair amount of information (no engine size, dyno conditions on each pull, engine size, exhaust, the list goes on) and cannot be used to draw any viable conclusion.

I actually found that graph when I did my search before installing my own EFR and immediately had to ignore it for the very reasons above.

Also, for the individual who states the GTX spools faster, that is not true. The basses behind the GTX line is simply flowing more for a given boost, meaning; 10 psi on a GT2871R makes x amount of power and 10psi on a GTX of the same variety flows several lbs more at the same 10psi boost level. If you would like a graph of a GT3071R vs a GTX3071R, I will gladly post it.

It's an Opel Vectra 2.0T AWD.

The dyno's were all done at Vmax performance. That's all I could tell from the google translates terrible job ahhaha.

[Kingtal0n]

Data is data is data. As long as the variables are controlled, data is accurate. Every single dyno number is "corrected" in some way or another. A dyno is essentially a computer taking a couple measurements of force and making a computation from it.

A dynojet measures roller acceleration and based on the weight of the roller it knows horsepower. There is no "correcting" multiplier as with other instruments that may skew the number as the operator prefers.

I still need to know which engine is attached to a given turbo to get even the slightest idea of what it might do on mine. Doesn't make much sense to look at graphs for turbos on a 6L V8 for my 122 cubic inch application.

[PoorMans180SX]

Dyno's have correction factors built in that you can choose to use or not. If you use the same correction factor on all the data... It's the same thing.

Right because obviously that graph is from a 6L V8...

Given that we've all seen a hundred graphs of 2871r's on SR20's, we can compare those graphs to this one. Based on that comparison, you can see how this engine spools a 2871r. Extrapolate that comparison data to the other power curves and whala!, you have a rough idea of how each turbo is going to perform on your SR20. It's logic, and it's not that hard.

Maybe this just comes with seeing hundreds of cars with different combos on a dyno... Idk, it just doesn't seem that hard to me.

I could tell instantly that this engine was similar in displacement to an SR20.

[R3cK]

DANG! i asked vmax.de about specs for the diagram:

"GTX2867R : T25 - A/R 0.64 1,6bar konstant
HighFlow Lader : A/R Serie da Serienkrümmer 1,7bar konstant
GT3076R : T3 - A/R 0.82 1,8bar konstant
EFR6758 : T25 - A/R 0.63 1,5bar konstant
GT2871R : T25 - A/R 0.64 1,7bar konstant


Die Ladedrücke sind jedoch belanglos da die Unterschiede bei den Krümmern, Downpipes, Abgasseite der Lader, Nockenwellenprofile dies relationslos werden lässt. Der Vergleich sollte damals die unterschiedlichen Drehzahlbänder und Stationäre Ansprechverhalten zeigen um einen vergleich zu erhalten welches Setup einem Persönlich besser gefällt.

let me translate:
The boost pressure is trivial tho because there is no relationship between camshaft profiles, exhaustmanifold, downpipe and exhaust side of the turbo. The diagram should only show different rpm ranges and stationary response for choosing a personal favorite as a setup.

[AzS13hatch]

The thing that bugs me most about this thread is that you guys keep saying the op is using an sr20 when he specifies in the first line of his post its for a ka-t.

Either way, imo you should go with the 2867 over the other if you want more power in the future without changing turbos

[teqnick]

The thing that bugs me most about this thread is that you guys keep saying the op is using an sr20 when he specifies in the first line of his post its for a ka-t.

Either way, imo you should go with the 2867 over the other if you want more power in the future without changing turbos


I love you.


Sent from my iPhone using Tapatalk