Time For a new snail!

[softopz]

Last summer I got my project finished its a 71 l28et freshly built pretty much stock except bore over 1mm ,mild porting head/intake, ms2 fuel and spark. I was running 5psi in the beginning of the summer and by the end of summer I was pushing the turbo out of breather 15-17psi. I want to upgrade the turbo and would appreciate some feedback. My power goals are 280-330hp 1/4 mile and the occasional street push.

 

My Options:

-gt35r lots of member run this. Great turbo with room to grow later. Its a bit pricey but may be overkill for me.

-gt3071r don't see much guys here with this turbo a friend has this and a kind get for a good price its turbine=.63ar compressor .50 a/r

- t3/t4 my brothers old turbo needs a rebuild and new compressor wheel. He found this to be very laggy but I could just put a smaller compressor wheel since it needs one. I don't know I feel about a rebuilt turbo (balancing , seals etc..)

 

I would appreciate your input specifically on the gt3071r don't see any info with l28et.

[Xnke]

T04b V-trim compressor, on a 0.82 AR T3 turbine housing with a T350 turbine wheel.

 

That's a *little* overkill for your goals, as it can flow enough air for 400hp at the limit, but at 16lbs it will be very effcient and push 350hp at the same time.

[Xnke]

T04b V-trim compressor, on a 0.82 AR T3 turbine housing with a T350 turbine wheel.

 

That's a *little* overkill for your goals, as it can flow enough air for 400hp at the limit, but at 16lbs it will be very effcient and push 350hp at the same time.

 

Change out for a 0.63 AR housing if you're running a stock cam, but for those power levels I would be looking for headwork and a cam first.

[softopz]

So do you think the gt3071r is a bit to small . I'm highly considering the GT 30 because I got an awesome price on it At 600 its very tempting for a ballbearing slightly used.

My brothers had .63 housing and a 58trim compressor wheel. I guess I could put smaller wheel. Xnke what do you mean by t350 wheel? Now I'm leaning to the rebuild it will probably cost just as much as to go with gt30.

[Xnke]

I'm talking in T-series turbos...I don't have a need for a ball-bearing super-duper turbo to make 400HP. The T3/T4 hybrid I mentioned above will run you about 550$ ballpark brand new. Just ask for "A t3/t4 turbo with a stage 3 exhaust wheel and a T04B V-trim compressor" when you call the turbo shop of your choice. It will bolt directly to the exhaust manifold, If your stock nissan housing is machined to fit the larger exhaust wheel you can use the stock downpipe and wastegate actuator, and it does not interfere with the intake manifold or engine mounting. If you use a standard Garret-style housing, a 4-bolt flange downpipe would be needed and I would HIGHLY reccomend a 2.5" turn down, expanding up to 3" diameter before the second turn to get under the car for either turbine housing.

 

If you're going for the Bell approach, then this turbo isn't exactly the way to go...Go for a T04E series compressor and lay the boost to it.

 

If you Just Need a ball bearing turbocharger, then I would say the GT3071R is a very poor fit for what you plan. It doesn't get into the best islands till about 20lbs of boost and event then it's only flowing 32lbs/min...that's enough for 290 crankshaft horsepower, assuming a peak output at 12.5:1 AFR and a 0.5 BSFC. Not really perfectly realistic as it will be worse than that in the real world.

 

The GT3571R would do the same at only 15lbs of boost, which is MUCH more reasonable. At 18lbs of boost it's capable of about 330HP at the crankshaft, using the same assumptions above.

 

Looking at the T04B-V trim compressor, you can get 250HP at 12lbs of boost, and as much as 330HP at 23lbs of boost, and remain in the peak effienciency island the entire time. It's also far less costly.

 

To hit your mark of 330RWHP, we need 390 flywheel HP assuming a 20% drivetrain loss. I would look for a turbo compressor that can produce 45lbs/min of air at a pressure ratio between 2 and 2.25, and keep it on the island. You will need a cam and headwork to be able to sustain a compressor that can do this!

 

Looking at a T61 compressor map, we can easily hit 45lbs/min at 76% effeciency at a pressure ratio of 2.2, or about 18lbs of boost. Not bad...and probably do-able on pump gas. That's 340-350 RWHP capable.

 

A T70 compressor would also be more than capable. We're talking a 2% drop in peak effeciency between the GT series compressors and the T series compressors, but a 40% difference in price...

Edited February 12, 2014 by Xnke

[Tony D]

I'm talking in T-series turbos...I don't have a need for a ball-bearing super-duper turbo to make 400HP. The T3/T4 hybrid I mentioned above will run you about 550$ ballpark brand new. Just ask for "A t3/t4 turbo with a stage 3 exhaust wheel and a T04B V-trim compressor" when you call the turbo shop of your choice. It will bolt directly to the exhaust manifold, If your stock nissan housing is machined to fit the larger exhaust wheel you can use the stock downpipe and wastegate actuator, and it does not interfere with the intake manifold or engine mounting. If you use a standard Garret-style housing, a 4-bolt flange downpipe would be needed and I would HIGHLY reccomend a 2.5" turn down, expanding up to 3" diameter before the second turn to get under the car for either turbine housing.

 

If you're going for the Bell approach, then this turbo isn't exactly the way to go...Go for a T04E series compressor and lay the boost to it.

 

If you Just Need a ball bearing turbocharger, then I would say the GT3071R is a very poor fit for what you plan. It doesn't get into the best islands till about 20lbs of boost and event then it's only flowing 32lbs/min...that's enough for 290 crankshaft horsepower, assuming a peak output at 12.5:1 AFR and a 0.5 BSFC. Not really perfectly realistic as it will be worse than that in the real world.

 

The GT3571R would do the same at only 15lbs of boost, which is MUCH more reasonable. At 18lbs of boost it's capable of about 330HP at the crankshaft, using the same assumptions above.

 

Looking at the T04B-V trim compressor, you can get 250HP at 12lbs of boost, and as much as 330HP at 23lbs of boost, and remain in the peak effienciency island the entire time. It's also far less costly.

 

To hit your mark of 330RWHP, we need 390 flywheel HP assuming a 20% drivetrain loss. I would look for a turbo compressor that can produce 45lbs/min of air at a pressure ratio between 2 and 2.25, and keep it on the island. You will need a cam and headwork to be able to sustain a compressor that can do this!

 

Looking at a T61 compressor map, we can easily hit 45lbs/min at 76% effeciency at a pressure ratio of 2.2, or about 18lbs of boost. Not bad...and probably do-able on pump gas. That's 340-350 RWHP capable.

 

A T70 compressor would also be more than capable. We're talking a 2% drop in peak effeciency between the GT series compressors and the T series compressors, but a 40% difference in price...

I think I just mentioned to someone the formulas for a 350hp L28 are on here ad nauseam...and here is a perfect example of step by step spooning!

 

I think I shall link him to this post!

[dexter72]

Thanks Xnke and Tony D,

 

Tony i was just reading the other thread. Now i have to figure out costs of the headwork and cam swap.

[softopz]

Hey we all got spoon fed as a babies.

Thanks for the reply it was very informative.The good thing is I already have a nice 2.5" downpipe opening to 3" ,1ft resonator and magnaflow exhaust. I am not a bells and whistle type trust me this has been a budget build that's why its taken so long haha. You just gave me the extra push to rebuild that t3/t4 I got laying around which I could also retain my internal wastegate. Saves me some money for clutch and tune.

Edited February 13, 2014 by softopz

[CarJway]

Have you looked at the Precision Billet 5858? I currently run that turbo with a cam, and if I recall from my last dyno session, boost threshold was around 3300/3400 at 19lbs. No one that has been in my car has ever used the word lag to describe how the car comes back off of boost.

 

I do see that the power levels you are aiming for are the 300 range, so this might be a little on the larger side. For reference I am running a stock l28et block, making a little under 400 whp. (car is used for road course/driven hard every chance possible) I will try to dig up a dyno plot with boost on it...

[softopz]

What cam are you running ? is it a custom grind or like the MSA turbo cams?

 

edit I just researched this turbo they come in both journal and ball bearing which are you running and what your AR?

Edited February 16, 2014 by softopz

[zack_280]

I'm running a GTX3071R turbo.  My car is running megasquirt and has not been properly tuned, but I have spent a bit of time messing with it on the street.  I did two pulls on an eddy current dyno and it made 245HP and 240lbft at 10PSI (but it did creep up to about 10.7PSI).  This was a conservative dyno.  I have a 1.01A/R turbine housing and was at full boost at ~3500RPM.  I am quite happy with it and it will have no problem supporting 400HP.  Hopefully this info is helpful.

[240zdan]

I'm talking in T-series turbos...I don't have a need for a ball-bearing super-duper turbo to make 400HP. The T3/T4 hybrid I mentioned above will run you about 550$ ballpark brand new. Just ask for "A t3/t4 turbo with a stage 3 exhaust wheel and a T04B V-trim compressor" when you call the turbo shop of your choice. It will bolt directly to the exhaust manifold, If your stock nissan housing is machined to fit the larger exhaust wheel you can use the stock downpipe and wastegate actuator, and it does not interfere with the intake manifold or engine mounting. If you use a standard Garret-style housing, a 4-bolt flange downpipe would be needed and I would HIGHLY reccomend a 2.5" turn down, expanding up to 3" diameter before the second turn to get under the car for either turbine housing.

 

If you're going for the Bell approach, then this turbo isn't exactly the way to go...Go for a T04E series compressor and lay the boost to it.

 

If you Just Need a ball bearing turbocharger, then I would say the GT3071R is a very poor fit for what you plan. It doesn't get into the best islands till about 20lbs of boost and event then it's only flowing 32lbs/min...that's enough for 290 crankshaft horsepower, assuming a peak output at 12.5:1 AFR and a 0.5 BSFC. Not really perfectly realistic as it will be worse than that in the real world.

 

The GT3571R would do the same at only 15lbs of boost, which is MUCH more reasonable. At 18lbs of boost it's capable of about 330HP at the crankshaft, using the same assumptions above.

 

Looking at the T04B-V trim compressor, you can get 250HP at 12lbs of boost, and as much as 330HP at 23lbs of boost, and remain in the peak effienciency island the entire time. It's also far less costly.

 

To hit your mark of 330RWHP, we need 390 flywheel HP assuming a 20% drivetrain loss. I would look for a turbo compressor that can produce 45lbs/min of air at a pressure ratio between 2 and 2.25, and keep it on the island. You will need a cam and headwork to be able to sustain a compressor that can do this!

 

Looking at a T61 compressor map, we can easily hit 45lbs/min at 76% effeciency at a pressure ratio of 2.2, or about 18lbs of boost. Not bad...and probably do-able on pump gas. That's 340-350 RWHP capable.

 

A T70 compressor would also be more than capable. We're talking a 2% drop in peak effeciency between the GT series compressors and the T series compressors, but a 40% difference in price...

 

 

Ball bearing super duper turbo. Explain: Ball bearing turbos help with transient response and have nothing to do with final power levels. Additionally FYI they do not determine what rpms they spool.

 

The T04b V trim is one of the worst/most inefficient compressor wheels out there, I wouldn't recommend it to anyone.

 

The gt3071r will support much more than 290 BHP. In fact the gt2860r will crush those numbers. Check your calculations.

 

GT3571r? I have not heard of such a turbo. Most gt35rs come with an 82mm exducer on the compressor side. Only the 28 and 30 was offered with a 71mm exducer from Garret as far as I know.

 

Your info is all over the  map man, its guys like you who have no idea what they are talking about, yet offer advice on sensitive subjects such as turbo selection which make forums BAD.

 

 

To the OP, stay way from rebuilding your old t3/t4, it probably needs more than its worth if its "laggy".

The GT35 is a great turbo and will run 500 hp with ease. 

The Gt3071R is a nice upgrade for street duty. The 3076 will be about the same with higher peak hp capabilites.

A new T3/T04E 50, 57 or 60 trim are all great options if you can find one cheap. 

Holset HE341s, HE351s, HY35s are also good options. Quick spool, bulletproof, cheap. That would probably be my choice if I was in your situation.

 

All are t3 flanged turbos and will meet your power goals.

 

I have ran both gt30 and gt35 turbos on my car in precision billet flavours. A GTX35r is going on next, trying to push 500whp on pump gas on lowish boost

Edited February 16, 2014 by 240zdan

[Xnke]

I suggest you look at the compressor maps again. I chose the turbos I did for peak compressor effeciency and cost effectiveness...and while all those turbos listed can produce more power, they will not do so effeciently.

 

I suggest YOU look at the requrements for airflow in lbs/min for your engine...then determine just how much air you need to make your crankshaft horsepower, and subtract out your drivetrain losses.

 

Yes, there is a Garret GT3571R. I got my compressor maps from Garret...I do spec and sell turbochargers locally and my math usually comes out within 30HP of what I say an engine will make with that compressor at the specified operating point. What's the point of choosing a 3071R and having to cram 40lbs/min out of it at 63% compressor effeciency? Might as well run an Eaton M112 positive displacement super and skip spool time altogether!

[softopz]

I didn't want to stir sh#t up. I had a feeling the gt30 I was looking at was more than capable to bring me to 350hp . The guy selling is coming off a rb25 and made 450hp at 15psi mind you the rb has way better head flow. I was asking for info and researching before pulling the trigger. My use however I don't care too much for quick spool it will be mostly 1/4 and pulls . And in a way I do prefer a bb not because its new and shiny its better technology, from the turbine and spool is way better ( from experience with my brothers setup) journal bearings have been around for quite some time now.

[240zdan]

I suggest you look at the compressor maps again. I chose the turbos I did for peak compressor effeciency and cost effectiveness...and while all those turbos listed can produce more power, they will not do so effeciently.

 

I suggest YOU look at the requrements for airflow in lbs/min for your engine...then determine just how much air you need to make your crankshaft horsepower, and subtract out your drivetrain losses.

 

Yes, there is a Garret GT3571R. I got my compressor maps from Garret...I do spec and sell turbochargers locally and my math usually comes out within 30HP of what I say an engine will make with that compressor at the specified operating point. What's the point of choosing a 3071R and having to cram 40lbs/min out of it at 63% compressor effeciency? Might as well run an Eaton M112 positive displacement super and skip spool time altogether!

 

 

I am not calculating anything! I have a 500whp dyno chart and 11 second street tire pass you can sign off on. 

And BTW, I make turbos for a living. So dont try to impress me with words like efficiency, especially when you're suggesting ancient technology V trim turbochargers which I THROW away.

 

OP run a 30r on it and shred some tire. You'll love it. Plenty of people running them on rb25s making well over 350whp on them. If you buy a an old school V trim, the only thing you'll be doing is clearing out old unwanted stock!

Edited February 17, 2014 by 240zdan

[240zdan]

I didn't want to stir sh#t up. I had a feeling the gt30 I was looking at was more than capable to bring me to 350hp . The guy selling is coming off a rb25 and made 450hp at 15psi mind you the rb has way better head flow. I was asking for info and researching before pulling the trigger. My use however I don't care too much for quick spool it will be mostly 1/4 and pulls . And in a way I do prefer a bb not because its new and shiny its better technology, from the turbine and spool is way better ( from experience with my brothers setup) journal bearings have been around for quite some time now.

Yes, the GT series turbine wheels are what spools them up faster. The ball bearings themselves do not help the turbo spool earlier, but apparentley they do help with recovering boost between shifts. I notice no difference between journal and ball bearing turbos.

You are correct by saying the Gt30 is capable. Tons of people running them with fantastic results. Xnke is misinformed and his technical calculations should not lead you to believe that the GT30 will not be efficient at 350hp. It will make that with ease and still have plenty of puff left over.

[240zdan]

 

 

What's the point of choosing a 3071R and having to cram 40lbs/min out of it at 63% compressor effeciency? Might as well run an Eaton M112 positive displacement super and skip spool time altogether!

 

 

 

I am so tempted to make this my new signature with your name attached to it.

 

 

 

 

 

[seattlejester]

Don't want to step on your toes, but I think you need to relax man. Xnke never said anything about ball bearings spooling faster or anything. Just talking about their price point. If power is the goal, a ball bearing turbo is not as relevant as a correctly sized/spec'd turbo. And the ancient technology you refer was a suggestion to an affordable alternative to reach the OP's power levels. I'm sure if money was no object there are some EFR turbo's that could be recommended.

 

Most hp quotes are with regular gas, here in the states it's hard to get more than 91 octane in places. So some figures may be on the conservative side. Also down in the states it can be a lot warmer then it gets up north, so if the numbers seem low there are reasons.

 

Which is why with varying environmental factors, it is easier to discuss the spec's of the turbo itself, which requires the correct terminology. I highly doubt it was an attempt at impressing anybody. We didn't see the term adiabatic efficiency even once .

 

Curious, is the 500hp number with pump gas? 

[240zdan]

Don't want to step on your toes, but I think you need to relax man. Xnke never said anything about ball bearings spooling faster or anything. Just talking about their price point. If power is the goal, a ball bearing turbo is not as relevant as a correctly sized/spec'd turbo. And the ancient technology you refer was a suggestion to an affordable alternative to reach the OP's power levels. I'm sure if money was no object there are some EFR turbo's that could be recommended.

 

Most hp quotes are with regular gas, here in the states it's hard to get more than 91 octane in places. So some figures may be on the conservative side. Also down in the states it can be a lot warmer then it gets up north, so if the numbers seem low there are reasons.

 

Which is why with varying environmental factors, it is easier to discuss the spec's of the turbo itself, which requires the correct terminology. I highly doubt it was an attempt at impressing anybody. We didn't see the term adiabatic efficiency even once .

 

Curious, is the 500hp number with pump gas? 

 

The ball bearing/spool comment was directed at softopz.

 

T04b V trims suck, end of story. Plenty of better options out there that are similarly priced.

Take a look at  the compressor map for yourself.

 

Softtopz states he can get a deal on a GT3071r and his power goals. Gt3071r wll easly reach his goals. Xnke recommends some garbage turbo which barely anyone uses because of the poor compressor wheel design. He states the GT3071r will be choked when you can clearly see on the compressor map it will not be.

 

Misleading information on forums annoys me.

 

Yes I run pump and daily drive my car, and no my turbo is no where near maxed out.

Edited February 18, 2014 by 240zdan

[softopz]

Just want throw an update I appreciate all the input . today is a good day I was about to buy the gt30 then I took my brother old 240! Stroked /forged 3l complete car.its got a gt35 on and tons of other goodies. Last year he got dyno tuned at 400hp at 17 psi. The guy who bought I guess didn't like it his loss my gain.