3rz Rockcrawler Turbo Build Questions

I'm seing LCE and other turbo options calling for a T3/T4-T04E option but I can't find any compressor maps. How does this turbo option compare to a GT3071? It seems slightly bigger. Would it still be a good option or too big?

 

I believe the t04e is basically just a Garrett 60-1 if I remember right. It's exactly what Zane runs on his truck. If that's the case, it will be big for a 3rz I think. Unless you had more rpm and wanted top end power.

 

Just to confirm, The specs i'm seeing:

Turbine Trim: 74.2
Turbine A/R: 0.63
Turbine Inducer: 64.8mm
Turbine Exducer: 55.8mm

Compressor Trim: 48.1
Compressor A/R: 0.5
Compressor Inducer: 52.7mm
Compressor Exducer: 76mm

This would be a too big?

 

That turbine wheel isn't too bad, but the 3071 is a 60/55 turbine wheel. So the t04e will be slower to spool than the 3071. It wouldn't necessarily be too big, but it would be on the laggy side. That might be offset enough by the smaller turbine housing though. My 2rz with a .82 ar 3067(a smaller compressor wheel version of the 3071) I think will be perfect on the 3rz im dropping in. It has a great powerband. It might be similar in spool to the one you listed.

 

I don't think it's an ideal turbo for your use case; a bit on the large side, older tech with larger wheels that don't spool as fast, etc. That's likely a Chinese copy of the Garrett T04E compressor because it doesn't correlate to any of the old original specs. That size is very widespread across ebay and the like (even I have one, lol). If you're looking for compressor maps, it's somewhere between a 46-trim and a 50-trim. The turbine is comparable to a T3 stage III. Really cheap ones also have suspect wastegate actuators; the one I got had a cracking pressure over 20psi.

The 60-1 compressor is one of many compressor sizes from the older T04B line.

 

Thank you both for confirming. I see what you are saying now on the turbine side. I am admittedly looking at china turbos. I was trying to at least go with the maxpeedingrods as they seem to have somewhat of a following that says they will doo what they are supposed to do.

Opt 1: The only Turbo they have with a 60mm/55mm turbine was their new BB billet wheel turbo for a little over $500.
https://www.maxpeedingrods.com/prod...-turbo-gt3071-up-to-30-bar.html?search=GT3071

Turbine Trim: 80.7
Turbine A/R: 0.82
Turbine Inducer Diameter: 60mm
Turbine Exducer Diameter: 55mm
Compressor Trim: 52.8
Compressor A/R: 0.63

Opt 2: Pulsar PSR3071 https://www.pulsarturbo.com/product/psr3071-gen2-compact-dual-ball-bearing-turbocharger/

• Compressor Wheel: 54*71mm
• Turbine Wheel: 60*55mm
• Turbine housing 0.64 or 0.82
• Compressor Inlet: 3″ Hose
• Compressor Outlet: 2″ Hose

Opt 3: Throw all caution the the wind and get a ebay special 3071 spec for $140 knowing that if it isn't the right turbo I will at least have a data point of what I want to improve.

One thing that concerns me is how the turbo is going to react with the 5.38 axle gears. Am I going to get enough load on the engine to build boost?

 

I can't recommend pulsar turbos enough for the price point. Mine is very well machined, very well balanced, and has fantastic response. I also personally know a guy local to me that runs one on his k swapped civic hatch that runs 8's, and pushes 55psi through it. They are killer for the price. I have a .82 ar housing on my 2rz and it still spools up very reasonably. I had a .63 on it, and it was about the same spool, maybe slightly earlier, but I felt like it fell off earlier on the top end

 

I was actually looking at those recently and all I found were rods for the 2RZ which are 12mm shorter than 3RZ.

Probably yes if you spend any amount of time over ~30-40% throttle. Your 42s bring the effective gear ratio down to being comparable to a 29"/3.73 combo.

 

You do NOT want a GT30 on anything less than a 4L engine. Sorry if that's my only contribution but I'm late

 

Gt30 as in 3071? If so, that is wildly inaccurate. That turbo shouldn't be on anything larger than a 3.0-3.2L, it's too small on the turbine side, and is listed as such on Garrett's website.

I have 35" tires on 5.29 gears(I'm switching to 37's very soon as I over geared my truck) and on the dyno, I make 15.5psi at 3700, and on the street I can make 10psi at 2300-2800 pending what gear I'm in. It should be plenty responsive on a truck with 42's. In fact, I bet you would spend a lot of time in boost honestly.

 

At a PR of 2 you will be flowing roughly 34lb/min of air on a 2.7L engine at 5500RPM. You're barely halfway through the compressor map. If he only wants 8psi, that's 1.54 and only 26lb/min and he's barely entered it.

A 4.0L at a PR of 2 (14.5psi) and 5500RPM is 50lb/min, so you'd tune out the high end. Since he's focused on low RPM torque, this would be much more in line with expectations

 

You're focused on the wrong side of the turbocharger, you're telling this to someone that is running a 3071 already BTW

 

ah, I see that now. Weird to me that they would mismatch capabilities to that degree

 

The 30 side is the turbine side. The 71, 76 or 82 is the compressor side. They pair the same compressor wheels with two different turbine wheels so the combination gives a wide range of engine displacement options that all can provide up to the max horsepower of the compressor wheel. However, you are talking purely theoretical numbers with the pressure ratio. You could very likely see 4-5:1 ratio when using such a small turbine wheel with a large engine. And just because you aren't looking to utilize the entirety of the compressor flow, it doesn't necessarily mean you go smaller on your turbo. As long as it's sized appropriately, response isn't an issue, and you just use less of the capability. If you go too small, you can end up hurting your response AND your top end at the same time.

 

PR is not a ratio of exhaust to intake, it's inlet to outlet of the compressor, so it's a function of atmospheric pressure and engine work, limited by wastegate control; so it's actually quite predictable. I still don't see why they would slap a relatively huge compressor housing on a restrictive exhaust housing that's incapable of flowing what the cold size could allow - there's no benefit vs a smaller compressor other than probably next to negligible flow loss.

 

I think the nature of your second sentence proves that indeed the first is not as predictable as once thought. Also what is that vehicular hermaphrodite in your avatar picture?

 

I mean it's not difficult to measure... I could go plot a realistic overlay on my truck and compressor maps right now (or I could guesstimate since I know my truck pretty well at this point)

AI hilarity

 

I think you could reverse engineer it yes, but to initially engineer it spot on using "should be's" often doesn't work in a world of "is". This is the best part about repeatedly talking about turbos with engineers... I just wish I got to talk to turbo engineers.

 

Incorrect, pressure ratio is the ratio of exhaust entering the turbo to the pressure of air leaving the turbo. 10psi of boost pressure to 20psi of exhaust back pressure in the turbo manifold equals a 2:1 pressure ratio. That's why people run exhaust map sensors to determine turbo efficiency. And the reason they would use that, along with different turbine wheels paired to the same compressor wheels, is to cover a large range of exhaust flow(displacement range) for the same given compressor CFM.

 

Idk where you're getting this information, because even Garrett themselves disagree
https://www.garrettmotion.com/knowledge-center-category/oem/expert/
https://www.garrettmotion.com/wp-content/uploads/2019/10/GAM_Turbo-Tech-103_Expert-1.pdf