Sizing a turbo

[Dusty]

Scott do you smoke crack?

What do you mean by:
"In reality, unless you are going after a one-off application, just about every Garrrett will either be too big or too small to run 7psi throughout the rev range."

That is nonsense friend. Try and tell that to Garrett. There are plenty of options for motors this size.
look at this map

http://not2fast.wryday.com/turbo/maps/GT35compress.jpg
this one is a bit smaller than the avo

or this one is a bit larger
http://not2fast.wryday.com/turbo/maps/gt40-56trim.jpg

http://not2fast.wryday.com/turbo/maps/t04b-h3.gif
this one shows you could be driving down the highway and boost up a hill at 6-7psi and be over 65% efficiancy. Whats wrong with that? even though efficiency is not perfect you still get more power than invested with an eaton m90.

this is a gt35r
lf all you have is maps I dont think you could postulate better than this for our motor
http://not2fast.wryday.com/turbo/maps/gt35rcompress.gif
Now go ahead and try and post a better for this application.

 

[SUMOTOY]

Sumo-
I am used to 8:1 compression 3.8 liter GN turbo engines (300-700hp) and 4.1 to 4.5 liter Stage2 Buick race engines (1000hp+). We run 14psi on 91 octane and 20psi+ on 116 octane. A 9:1 engine isn't considered high compression by any means. It will spool a turbo faster though and won't need as much boost as an 8:1 motor to make the same power.

With 4.5 liters of displacement (which is a lot) and a forced induction friendly 9:1 compression it should spool most properly sized turbos quickly. Finding a small turbo that will spool under 2,000rpm will choke the top end unless they are sequentially setup like on the RX-7's and Supra's.

I'm used to 9.3:1 with 26psi on the 2.226 audis on 93 octane, I'm driving one today. The problem I see with the 1FZFE engine is that to run high boost levels, you need to crack the ECU code. The knock sensor, timing tables and fuel tables specifically. Then you need to go to the head gasket and change over to ARP's and most likely still have a headgasket problem. They have a HG problem in the stock truck.

Again, if we want to speak to 14psi, fine. That's not where this exercise is right now. It's at 7psi, and IMO, it would take someone really good to go after something higher. IME in N/A to bolt on force induction, 8psi is about max without changing from a bolt on to a true turbo conversion.

I'm comfortable with the 7psi low boost application in the SC. The problem with big turbos is they really aren't built for that. 14psi min really. IMEII, to get the torque hit, you need to lower the compression ratio or dial back the boost. That's where engines tend to blow IME.

The sequential in the RX7 is one of my favorites, as is the sequential supercharger + turbocharger used in the Lancia WRC Groupe B rally car back in the mid 80's.

Right now, I just don't see a good single turbo fit for a low boost 4.5liter motor. I see a lot of duals that would work really well....

Cheers

SJ

 

[SUMOTOY]

Scott do you smoke crack?

What do you mean by:
"In reality, unless you are going after a one-off application, just about every Garrrett will either be too big or too small to run 7psi throughout the rev range."

That is nonsense friend. Try and tell that to Garrett. There are plenty of options for motors this size.
look at this map

http://not2fast.wryday.com/turbo/maps/GT35compress.jpg
this one is a bit smaller than the avo

or this one is a bit larger
http://not2fast.wryday.com/turbo/maps/gt40-56trim.jpg

Now go ahead and try and post a better for this application.

Dusty:
What's your target air at 1.5PR?

Read the map on number one, the avo one. At 1.5pr go over to max air lb/min. I get 65% Compressor Efficiency (CE), and you are really close to the choke line on the 76 trim, over it on the 71 trim, and you never get to the max compressor efficiency on either... You are barely on the Map. Too big for 7psi

The second one is closer, but you don't get to 72%CE until 2500engine rpm, and you skate below the max efficiency. CE sucks at low rpm and you are skating the surge line, and CE sucks at high rpm. Too big for 7psi

The third one won't hit 7psi until 2500, but it at least hits the high CE, but the CE sucks at high rpm as you head towards choking it.

Will any of them work? Sure. Me on crack? No Dusty,Garretts are designed to run at 90,000rpm, not 50,000. Ramp any of these up to 16psi, you have a point. You also have only identified the compressor side. Remember, you need to make sure that the turbine can move what you put thru the engine. IIRC, that's an issue with just about all the ones you have referenced, I cked them out already. Ideally you want to move over on the x axis as you increase PR, that allows the engine air demand to keep the compressor in the highest efficiency. When you throttle it back with a wastegate, you end up skimming from low CE to low CE. 65% is considered the absolute lowest CE to claim a 'gain' in the turbo world. If you are hitting it at the high engine rpm, most would agree you need a different turbo.

I also say if you run these, get a boost controller. These are big dogs just starting to chomp at the choke collar right when you are yanking at the wastegate.

SJ

 

[Dusty]

Scott the problem with boosting this motor is that it is not constructed of forged internals and wont last long beyond 10psi. At leaste this is what I have read as posted by arabs that frequent other places on this forum. With forged guts this motor can do stupid things. But 10psi would be rather fun too.

 

[Dusty]

"These are big dogs just starting to chomp at the choke collar right when you are yanking at the wastegate."

Nice

 

[Dusty]

scott scott scott

You are too much of an idealist. They work fine. Faith brother. You build that killer SC and others will follow. But until then....

 

[SUMOTOY]

scott scott scott

You are too much of an idealist. They work fine. Faith brother. You build that killer SC and others will follow. But until then....

Dusty:
Understand, I have put the wrong size turbo on several cars, I have a customer car 2.2L with a GT35R! Dusty, go over to my post on the M90. I can look at all the turbo maps you want, and see compromises. Will they work? Sure. Are they anywhere close to optimal? Haven't seen that yet. In fact, the M90 at 7psi (guaranteed, no overage) is the best match.

I know the problems with turning up boost pressure, I deal with all aspects of it daily.

I also KNOW that a wide variety of turbo apps with good fuel will yield performance gains, even one that sits at low CE.

Garrett designed all these big guns to run 2PR and higher. That's not going to change throwing 50 maps at me. Most low boost applications I'm aware of use a spec'd turbo. That's major dollars.

SJ

 

[SUMOTOY]

Garrett agrees with you on this as well. But the GT35R is a whole different animal and rated for 4.5L

I think that turbo is a bit small on the hot side Rick. It's going to ramp quickly, but I'd have doubts you can open the wastegate far enough to hold it to 1.5PR. My opinion is this one will tend to want to jump into overboost mode on the 80, especially on a downshift in the automatic. I wouldn't touch that turbo without a really good boost controller attached to a pretty good sized wastegate.

The compressor efficiency is good, but again, this turbo would do much better running 14psi trying to get the same airflow.

I'd also highly recommend that those with external WG turbos replace the Scroll to Wastegate boost feed line with silicone. If that line goes, you are done with that motor before you can back it off. With either internal or external WG, better yet, put a pop off valve in the intake manifold and set the boost pop off to 8psi.

These are really scarey MAPS for a low pressure turbo boys. They will certainly work, but I'd be concentrating my efforts on some good ways to assure that big dog never gets loose. You have potential exhaust energy ready to spool these pups past 2.5PR really fast!

Just my .02

SJ

 

[Cattledog]

Point well taken about the silicon tubing to the wastegate. I agree that most t04 turbos can be setup for big HP numbers.

I still fail to see how a T04B 60-1 or 62-1 would be a poor choice in this application intercooled/nonintercooled at 7 psi. Yes the turbo will be running in the lower end of the CE map.

I agree that the M90 is a good choice and a M112 is a better choice for a blower setup. But I am not buying a blower.

 

[gnx7]

Sumo- you have to realize that a 4.5i engine vs. a 2.2i engine running the same turbo are 2 different animals.

There are production LS1 (10:1 compression) 346ci (5.7i) engines running T-70 turbos at 15psi making 600rwhp..... not 25psi. The reason... they are higher compression and lots of cubes. The same engine with forged guts, 8:1 compression, and (2) T-66 turbos will make 1100rwhp+.

An 8:1 4.5i engine running 15psi will be equivalent to a 9:1 engine running 10psi in power output. The lower compression motor will be able to run much higher boost and take a little longer to spool..... but the 9:1 engine should theoretically make the same power output but at lower boost.

 

[SUMOTOY]

Point well taken about the silicon tubing to the wastegate. I agree that most t04 turbos can be setup for big HP numbers.

I still fail to see how a T04B 60-1 or 62-1 would be a poor choice in this application intercooled/nonintercooled at 7 psi. Yes the turbo will be running in the lower end of the CE map.

I agree that the M90 is a good choice and a M112 is a better choice for a blower setup. But I am not buying a blower.

CD:
I don't think or say that any of the turbo choice are poor. Only that they appear to be too big or too small, favor higher boost levels, and faster turbo speeds. More specifically, there is no optimal turbo for the I6 4.5L motor running low boost. It's not that most t04 turbos can be setup for big HP numbers, they are *designed* for big PR and HP numbers. They aren't designed for low PR and big HP numbers.

That's just in the MAPS. If you aren't buying a blower, there appear to be severral turbo choices that work, albeit all with compromises, and a lot of potential for catastrophic engine failure if let loose.

If I said more than that, you misread my words. I started the blower discussion under separate thread.

SJ

 

[SUMOTOY]

Sumo- you have to realize that a 4.5i engine vs. a 2.2i engine running the same turbo are 2 different animals.

There are production LS1 (10:1 compression) 346ci (5.7i) engines running T-70 turbos at 15psi making 600rwhp..... not 25psi. The reason... they are higher compression and lots of cubes. The same engine with forged guts, 8:1 compression, and (2) T-66 turbos will make 1100rwhp+.

An 8:1 4.5i engine running 15psi will be equivalent to a 9:1 engine running 10psi in power output. The lower compression motor will be able to run much higher boost and take a little longer to spool..... but the 9:1 engine should theoretically make the same power output but at lower boost.

Er, 2 of those 2.2 turbos are a bolt on to the 4.5L. I understand large applications, including the GNX. It's not the HP, it's the HP/liter that needs to be concentrated on. I've been playing in the arena of 350ATWHP in 2.2L on 93 octane for several years, that's 159HP/liter, the 5.7 you speak of is 105HP/Liter (that's the stock audi 20vt application btw), my peak dyno run is 470ATWHP, that's 213HP/Liter, even the 1100HP 5.7 doesn't make that. Not bragging, that's just how I look at any tweeks in the turbo world. So they really aren't different animals, it's all volumetric and thermal efficiency of combustion engines yielding some comparable number, IMO.

Your effective compression ratio equivelency is correct to the charts, but is a bit oversimplified IMO/E. What I find running on the dyno, and with programming stand alone EFI (034efi dot com) turbo applications is that the equivelent boost is not the whole story. What I find is a massive torque increase with a very slight decrease in compression ratio (in the audis, the common drop is 9.3:1 to 8.6:1 at 26psi gaining torque numbers of almost 30%) Straight up boost is the same, but timing advance on the lower compression motor combined with the resulting boost advance, combined with really high volumetric efficiency, massively skews that straight up comparo. Intake tuning and (dual resonance) changes can yield even higher discrepencies.

From strictly a Effective Compression Ratio standpoint, you are correct. From complete fuel/timing/boost tuning, there is a lot of documentation that supports dropping compression ratios having a much higher advantage thatn strictly ECR.

I can look at a lot of turbos that will work on the 1FZFE. Their disadvantage (vs a M90 up to 8psi) is that the turbos are designed to run twice the boost targetted for a bolt on application. What is indicated in the MAPS is that several of these applications have really low compressor efficiency because of it, several miss the peak CE all together.

Right now, there are a handful or less of applications that are actuall attached to the engine, with just as many different manifolds and wastegates. None of them use a boost controller. None of them are stand alone EFI, none of them have 'boost' recognition sofware. As such, they are bolt on piggy back systems.

Given all that, compared to the theatre I play in daily, the foray into 1FZFE turbos is in it's infancy. Not knocking it, only pointing out the n is really low, as is the knowlege base in that n.

I'm pretty convinced that no one wants to blow up a motor, I know I don't. Given where this forum is, I say baby steps are very important. A bolt on turbo works, there is no doubt in my mind. There is also no doubt in my mind that many of the compromises found in turbo applications, just aren't present in the SC. Does the SC come equipped with all the goodies? No. Does that make the turbo application better? I don't believe so, that's a jump missing some obvious steps.

Cheers

SJ

 

[gnx7]

Sumo- you are talking about high boost comparison's and this thread was for a production 9:1 longblock 4.5i LandCruiser engine running 91/93 octane and under 10psi. Different ballgames.

Here is a healthy LS1 for you making around 1600-1800HP:
http://www.w2wpowertrain.com/t-Casper-2.aspx

275hp+/liter. At the rear wheels same HP/Liter as your lil Audi motor.

 

[parabola]

I've been playing in the arena of 350ATWHP in 2.2L on 93 octane for several years, that's 159HP/liter, the 5.7 you speak of is 105HP/Liter (that's the stock audi 20vt application btw), my peak dyno run is 470ATWHP, that's 213HP/Liter, even the 1100HP 5.7 doesn't make that. Not bragging, that's just how I look at any tweeks in the turbo world.

I've got you beat at *217HP/L! And yes, I'm bragging! ;p

I'm pretty convinced that no one wants to blow up a motor, I know I don't. Given where this forum is, I say baby steps are very important. A bolt on turbo works, there is no doubt in my mind. There is also no doubt in my mind that many of the compromises found in turbo applications, just aren't present in the SC. Does the SC come equipped with all the goodies? No. Does that make the turbo application better? I don't believe so, that's a jump missing some obvious steps.

I completely agree that baby steps are in order, but I don't think the existing FI solutions max out the potential the 1FZ-FE and I don't think that turbos as a whole should be thrown out of the equation.

*193HP/L on 93 octane though.

 

[SUMOTOY]

Sumo- you are talking about high boost comparison's and this thread was for a production 9:1 longblock 4.5i LandCruiser engine running 91/93 octane and under 10psi. Different ballgames.

NO<NO<NO. I want to speak directly to low boost comparos, because that is exactly my point. Size the turbo for 7psi, then ck the SC output and work the math on both. My claim all along is that a low PR turbo on the 4.5L motor will have more compromises than an almost perfect aiflow match with the SC at 1.5PR. It is exactly a different ballgame.

Here is a healthy LS1 for you making around 1600-1800HP:
275hp+/liter. At the rear wheels same HP/Liter as your lil Audi motor.

That's only what I've done, so I don't feel so bad. Here's what Dahlback with the I5, at 379HP/L. Ck out the pics, it's pretty impressive.

http://www.rsportscars.com/eng/cars/golf_dahlback.asp

it's a hoot to watch too
http://video.google.com/videoplay?docid=-3454923200934515429

Then again, Audisport had the 2.2 at 1100HP in race trim....



SJ

 

[tiorio]

NO<NO<NO. I want to speak directly to low boost comparos, because that is exactly my point. Size the turbo for 7psi, then ck the SC output and work the math on both. My claim all along is that a low PR turbo on the 4.5L motor will have more compromises than an almost perfect aiflow match with the SC at 1.5PR. It is exactly a different ballgame.

Ok, maybe we need to be more specific on what the compromises are and how they affect the total package. A turbo running below peak compressor efficiency does not make it any better or worse than a perfectly matched supercharger. CE is only one part of the equation, even if you take intercoolers and fuel mods out of the equation, right? So there ARE downsides to either application but we continue to focus on the fact that it's very hard to find a turbo that gets close to peak CE in our low-boost situation but just because it's not running at peak efficiency may not negate it's advantages over the SC. The M90 isn't the most efficient design from the get-go...

Cheers!

 

[SUMOTOY]

Ok, maybe we need to be more specific on what the compromises are and how they affect the total package. A turbo running below peak compressor efficiency does not make it any better or worse than a perfectly matched supercharger. CE is only one part of the equation, even if you take intercoolers and fuel mods out of the equation, right? So there ARE downsides to either application but we continue to focus on the fact that it's very hard to find a turbo that gets close to peak CE in our low-boost situation but just because it's not running at peak efficiency may not negate it's advantages over the SC. The M90 isn't the most efficient design from the get-go...

Cheers!

That's really not true, it has very good efficiency at low boost. It gets a bum rap, because it sucks at high boost. I only look at airflow out of two compressors, either can hit 1.5PR. Up to 8psi, the TRD, stays right on the demand of the engine. You move the psi range in the turbo application, it changes the application again, I just ran it all thru my turbo spreadsheets. The turbo app changes based on what boost you are using, especially at low boost.

Again, I posted the numbers on the M90, and they look really good. I also ran those same numbers thru my fueling spreadsheets, and believe that the stock injector can't flow enough fuel, even with a 1:1 rising rate fuel pressure regulator. Remember, you are only going increasing fuel pressure (1:1FPR) from stock 3bar to boosted 3.5bar. You need either a variable rising rate regulator or a different injector.

I really believe there is a lot more room in either system in terms of fuel, and tons of room in the SC, cuz there is no intercooler or fuel mods with it.

SJ

 

[Dusty]

Scott
What if the TRD SC doesn't have a problem with fuel delivery? What if when it boosts to 7psi it dosesn't lean out? What if it is working as good as it can from a fuel delivery standpount at 1.5PR?
If the SC doesn't have a problem with fuel delivery then the only real improvement to be made is with an intercooler-which is substantial. Remember that except for Christo's wonderful work most everyone else running a turbo (myself, Mike, Turbocruiser, etc) is using the engine management that Mr. T gave us to manage the engine under the influence of the Turbo. Mike claims his Safari turbo is more powerfull than his TRD SC.
You must have access to some nice tunning a/f meters. Why dont you borrow one and take a few blasts down the highway and see if your oe injectors can keep up. I havn't seen a map yet of the TRD SC a/f map at 1.5PR. How do we know the SC isn't performing about as good as it can?

Christo illuded that the a/f map done with the SC and the Rising rate regulator was not the tuned version. It their a SC a/f map (with or without extra fuel provisions) that is actually tuned?

 

[tiorio]

Something is not right with the logic here and I can't quite put my finger on it. There's something bigger than what we're looking at...

You say that

I only look at airflow out of two compressors, either can hit 1.5PR. Up to 8psi, the TRD, stays right on the demand of the engine

I think that's the point, at what cost does the supercharger produce this airflow? You have a tradeoff between losses and gains, the perfect match between engine demand and compressor output means nothing if it requires a significant amount of power to get there.

 

[MSGGrunt]

would this be a good choice for the 1FZFE with the .81 outlet AR? I'm ready to buy, just need to find the right turbo.



http://cgi.ebay.com/OBX-T04-Turboch...DVWQQrdZ1QQcmdZViewItem?hash=item170038097414