I'm using someone else's post referring to a stock turbo vs a GT35r but the technical basis is the same:
Taken from http://www.e90post.com/forums/showthread.php?t=401958 (http://www.e90post.com/forums/showthread.php?t=401958)
The debate regarding this topic has come up over and over again in various forums, but I have yet to see a satisfactory explanation other than "big turbo flows more air at given psi". So I am going to attempt to explain this phenomenon while trying to include real world variables such as turbine backpressure, CFM, compressor efficiency, etc.
Now I am not an engineer with a degree in thermodynamics or mechanical theory, so while I believe my rationale is close to the truth, I don't believe it to be the absolute truth. So feel free to correct me or add as you wish.
For simplicity sake, let's say we have an n55 engine, GT35r and n55 stock single turbo in this comparison. As everyone knows, turbo has two main components: compressor and turbine. Let's break it down into components and evaluate it separately.
Compressor:
The GT35r compressor is larger than n55 stock turbo's. This means GT35r's compressor has greater surface area. Let's assume that two compressors are rotating at identical speed, let's say 25,000 rotations per minute. The compressor with larger surface area will obviously move higher volume of air than the smaller compressor. Also, while doing this, the work done by the larger compressor is translated into heat in lesser degree than the smaller compressor, thus giving it higher efficiency.
CFM: (cubic feet per minute)
It's a non-SI unit that measures the volume of gas that passes a given point in one minute. We have established that GT35r's compressor moves higher volume of air. We also know that this air has to pass through the intake manifold that's fixed in volume. Since the higher volume of air has to pass through the fixed space (intake manifold) in one minute, the velocity of the air is higher compared to air generated by the stock turbo which has lower CFM, thus lower velocity.
PSI: (pounds of pressure per square inch)
Pressure is measured at intake manifold. This pressure is generated by air molecules moving rapidly and hitting the inner surface of the intake manifold.
This kinetic energy of the air molecules are proportional to the temperature.
In other words, higher temperature will allow air molecules move at faster speed and create higher pressure.
Real world example of this is a can of butane gas. When you heat this up what happens? The pressure inside the can increases due to higher kinetic energy and the can blows!! But if you were to blow the can just by shoving in more butane at room temperature, you will have to put in ALOT more butane to do that.
We have established that stock turbo compressor blows hotter air compared to GT35r compressor. The hotter air has higher kinetic energy. So it's relatively easier for stock turbo compressor to generate 10psi of pressure because they are moving around so fast bouncing off of the surface of the intake manifold. The GT35r compressor, on the other hand, blows cooler air. So it requires more air to generate the same 10psi of pressure.
Since we know that density = # of moles of substance/volume, we know that the air from the GT35r compressor has higher density.
Turbine back pressure:
The turbine wheel is in the right smack in the middle of the exhaust flow, creating resistance. When the piston engines completes it's combustion cycle, it has to let out exhaust gases. Since the smaller turbine creates more resistance or back pressure, the motor cannot effectively expel all of the exhaust gases it produced. Large turbine wheel of GT35r reduces the resistance (back pressure), enabling more exhaust gases to be expelled at the end of the combustion cycle.
So let's put it all together.
What happens when the intake port opens? :
So let's assume that we have an n55 engine that's operating at 4000rpm.
The intake port of the n55 engine with stock turbo and n55 engine with GT35r are opened for same period of time. Intake manifold pressure for both reads 10psi. Few things happen in the car with a GT35r:
1. The air from GT35r moves at higher velocity into the cylinder due to higher CFM, so more air can go in before the valve closes.
2. Not only more air has entered the cylinder, the air from GT35r is denser because of higher efficiency of the compressor.
3. There is less exhaust gas remaining in the cylinder due to reduced exhaust back pressure. This allows more fresh air to enter the cylinder.
So, during the short period the intake valve is opened, air from the GT35r goes into the cylinder FASTER, and MORE air (oxygen) is available for combustion because the air is denser and there is more room for refresh air.
This is why a larger turbo makes more hp at given psi than a smaller turbo.
Now, go and upgrade..
Ok...
So here is my question... ( I have no mechanical experience)
Can you use these turbos on a XSport? And do you have to upgrade anything else in order to do this?
What is the HP/TQ gain with this upgrade? Are there any potential down sides to this for a non track daily driver?
I guess I should say "questions"...
Quote from: bigmoneycloser on November 05, 2013, 09:44:27 AM
Ok...
So here is my question... ( I have no mechanical experience)
Can you use these turbos on a XSport? And do you have to upgrade anything else in order to do this?
What is the HP/TQ gain with this upgrade? Are there any potential down sides to this for a non track daily driver?
I guess I should say "questions"...
Yes, these turbos will fit any of the transverse vehicles (all stock turbos are same part #).
Mike - BPD is supplementing his stock fuel system with meth, I don't know how the car will do on just a stock fuel system on the low boost setting yet. Somebody will have to blaze that trail for us. The ATP turbos will definitely make great HP in their lowest best setting, we just need more people with them on their cars for feedback. I don't see any reason why you would have any issues on your Xsport with these turbos.
Quote from: 4DRHTRD on November 05, 2013, 09:56:44 AM
Quote from: bigmoneycloser on November 05, 2013, 09:44:27 AM
Ok...
So here is my question... ( I have no mechanical experience)
Can you use these turbos on a XSport? And do you have to upgrade anything else in order to do this?
What is the HP/TQ gain with this upgrade? Are there any potential down sides to this for a non track daily driver?
I guess I should say "questions"...
Yes, these turbos will fit any of the transverse vehicles (all stock turbos are same part #).
Mike - BPD is supplementing his stock fuel system with meth, I don't know how the car will do on just a stock fuel system on the low boost setting yet. Somebody will have to blaze that trail for us. The ATP turbos will definitely make great HP in their lowest best setting, we just need more people with them on their cars for feedback. I don't see any reason why you would have any issues on your Xsport with these turbos.
Th fuel system is a problem for me, because there aren't many if any(except at track) places to get anything other than standard 93 octane here in NJ...
93 Octane should be fine, it would be great if we could get BPD to get LMS to do a 93 octane tune/dyno and 93 octane + meth tune/dyno to see where it's at. Hopefully they can also do a boost plot with AFR on their dyno to see the boost curve.
Quote from: 4DRHTRD on November 05, 2013, 10:02:33 AM
93 Octane should be fine, it would be great if we could get BPD to get LMS to do a 93 octane tune/dyno and 93 octane + meth tune/dyno to see where it's at. Hopefully they can also do a boost plot with AFR on their dyno to see the boost curve.
Lol
That statement is way above my Pay grade... Lol
I'm guessing LMS would write me updated tunes if I did the turbos without the fuel system.
But would I need or be in my best interest to have it dyno'd somewhere?
Not sure who in NJ I could trust to do that since LMS is where everything I have has come from and I have no idea anyone with an AWD dyno here?
Mike - BPD has the ATP turbos on his SHO, he's going to go see LMS to get a dyno tune soon. That will tell us how much HP the turbos make on stock fuel + meth, I'm also hoping he'll convince them to do a dyno without meth to see what the car does and if it behaves without meth.
That would be great to see without meth....
A possible good outcome would be all I need to pull the trigger!
Me thinks this thread is all my fault.... Thanks Mike for posting.
Another point needing to be made is that our stock turbos are VERY SMALL. That's why these ATP turbos will work and generate more potential CFM due to lower air temps. However, bigger might not be better if one already had plenty of turbo volume, ie. a single larger turbo. The latter is definitely more efficient, but creates lots of turbo lag.
So our stock very small turbos get peaky when pushed over 15 psi. ATP turbos provide steady air, up to and above the volume our engine can use with current Fuel system, without much more turbo lag. Probably the most important issue is that they also include better bearings and heavier duty parts per Mike's comments to me. And they won't work as hard as the stock ones, so should handle the abuse some of us are known to create, much better than the stock turbos.
The biggest unknown at this time is how much boost & CFM our stock fuel system can handle, with or without Methanol spray. If you guess wrong... Ford is not your friend....
I know that many that have had twin turbo cars. I.E. the mark iv supras and the 300 zx cars have swapped the twins for a single, larger tubo, as the single offered up more horsepower than a twin upgrade. have you guys put any thoughts to that?
I think that some of the F-150 owners are going to the single larger turbo since there is room in the engine bay to do so.
Quote from: SRT82ECOBOOST on November 05, 2013, 01:43:51 PM
I think that some of the F-150 owners are going to the single larger turbo since there is room in the engine bay to do so.
Nobody has done that yet, Full-Race has a prototype on their truck but nothing in production so far, they also have a big twin setup they have made manifolds for. ATP will be the first released to public turbo that I know of, should be finalized by end of the month, I've been saying that according to info from them for 2 months though :)
I need a conference call about alternate fuel and fuel delivery...(meth and E)
I just found out that the local ford dealer that has a big mustang Motorsports dept. stocks all that fuel all summer long, but nothing in winter.
I don't understand how people are using the meth or ethanol, so I don't know how it benefits me.
Would love more power to tool around with, but I'm not racing or going to the track, so not sure if that is just waste of money??
Quote from: bigmoneycloser on November 05, 2013, 02:37:24 PM
I need a conference call about alternate fuel and fuel delivery...(meth and E)
I just found out that the local ford dealer that has a big mustang Motorsports dept. stocks all that fuel all summer long, but nothing in winter.
I don't understand how people are using the meth or ethanol, so I don't know how it benefits me.
Would love more power to tool around with, but I'm not racing or going to the track, so not sure if that is just waste of money??
There's topics elsewhere on the forum that discuss E85 and methanol which are not the same thing and there's boards specific to those topics.
Not really a discussion point for bigger turbos though and why they make more power at the same PSI
The problem with a single large turbo is lag. Our cars are hitting peak torque just above 2000rpm's. With one single large turbo you wouldn't see power til 4000 rpm's.
Turbo lag is all relevant to compressor size and turbine housing AR .... you could make great power down low with a single 35R turbo with a T3 or T4 frame and a AR of .82 ....twins are not always the best or cheapest way
While we could do a conference call on all of this... I am up for some method of real-time internet conferencing... I think everyone needs to read as much as they can on turbos... and why small twins work better than larger single turbos in many situations... On the street they are much more user friendly... At the strip where you are trying to max performance and low et... not so much. I compiled a bunch of turbo and methanol (and other propellants) articles which BPD kindly moved over to this site. All good info, but may or may not apply to YOU or ME... depending on what we want to do with our Toys!
While I may be totally wrong... I think Ford did a good job picking turbos, DI and the rest of the package for most of us... For the rest of us- which may mean YOU and ME who post here and a big group of the rest... We need a bigger boost package which will work with what Ford has limited us with...
So.. what does this entail... My opinion -- (NOTE- I am dazed... confused and Verklempt!!!) is that we need bigger volume turbos and more fuel capacity, which can at this time be gained by Methanol, or with 4Dr's modded manifold, and his fantastic Squash fuel system... that isn't as cheap as methanol... but might be safer.... What we really need is bigger DI pump, higher volume DI injectors etc... but then we get to the drive train... Whoops!!!
So... the ultimate solution... buy a F-150 Tremor or another F-150 version that is close to our wheelbase... and swap bodies!!!! LOL LOL help me...LOL
Between this truck and my motorcycle build..... I may never be done with mods and upgrades....
Lol
Quote from: bigmoneycloser on November 05, 2013, 08:17:57 PM
Between this truck and my motorcycle build..... I may never be done with mods and upgrades....
Lol
My shooting buddies are hating my truck...lol.
Kinda glad for a cheaper hobby for a change of pace.
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Supra's go to big singles because they are more simple to plumb as well as the fact that there just isn't room for bigger twins. The fastest 2011+ turbo Mustangs are running a mix of single and turbo twin turbo setups. They are making 1100-1300rwhp so both can work.
Smaller twin setups have some advantages. They can be placed closer to the exhaust manifolds, which helps to enhance spool (the further downstream the turbos, the more heat is lost, and cooler exhaust loses volume and energy to spool the turbos with). Twins typically get equallized exhaust flow since they are typically placed the same distance away from the exhaust manifolds, where as a single typically has a short exhaust routing from the bank closest to it and a longer run from the other side of the engine.
Disadvantages are that there is more to go wrong with a twin setup. Two turbos, two wastegates, two oil lines, two coolant lines, etc. Twin setups are also typically heavier (more overall piping and the weight of a second turbo). Twins are also typically more expensive as you are buying a second turbo.
With the Platform, and specifically the 3.5 V6, part of the magic I believe is the packaging of the turbos so close to the exhaust manifolds. In fact, Ford was so intent to do this on the 2.0, that they integrated the exhaust manifold into the head casting. You can't attach a turbo any closer than that. The proximity to the exhaust in conjunction with size of the turbos work to help create the instance spool and torquey nature. Moving to a larger single setup should be reserved for the situations where a larger twin setup won't fit for packaging reasons unless you are looking at a race only application.
As far as a larger turbo making more power at a given boost level vs a smaller turbo, things have pretty much been covered, except for understanding compressor maps. It has somewhat been covered in noting that a larger turbo typically has lower intake temps vs a smaller turbo at the same measured boost level. When comparing turbochargers, and any forced induction application, one should look at the compressor maps and try to match up the compressor map to the intended operating range of the turbo or supercharger. If you go too big or two small, you will operate outside of the peak efficiency range and will see less than ideal results.
With the upgraded ATP turbos, I don't think you are going to see any updated compressor maps, since they are upgrades to an existing turbo. As manufacturers start coming out with new turbos, we'll want to pay close attention to compressor maps on top of all the other variables.
Ok guys..
If you did a turbo upgrade without a fuel system upgrade. Assuming you would have some gains, just not as much as with an upgraded fuel system..
Where would most of the power be? Are you going to see all the power up over the 5-6k rpm?
And would it hurt you 0-3k rpm power??
I'm asking because, if all the extra power is up top and the bottom doesn't see any power or loses some power, this would be a bad mod for a non track daily driver...
Any thoughts would be great..
As far as turbo, I would be looking and the ATP twin turbo upgrade?
Thx
Quote from: bigmoneycloser on November 06, 2013, 04:38:36 PM
Ok guys..
If you did a turbo upgrade without a fuel system upgrade. Assuming you would have some gains, just not as much as with an upgraded fuel system..
Where would most of the power be? Are you going to see all the power up over the 5-6k rpm?
And would it hurt you 0-3k rpm power??
I'm asking because, if all the extra power is up top and the bottom doesn't see any power or loses some power, this would be a bad mod for a non track daily driver...
Any thoughts would be great..
As far as turbo, I would be looking and the ATP twin turbo upgrade?
Thx
With the atp turbo upgradeyoi wont see much if any change in spool and power in the lower rpms. They are still small turbos but reworked to allow them to make more power.
The ones they are talking about causing lag are the single much much larger turbos then the atp upgrades.
No one has yet to push the stock fuel system by itself with upgraded turbos so not sure what gains wpuld be exactly
Quote from: bigmoneycloser on November 06, 2013, 04:38:36 PM
Ok guys..
If you did a turbo upgrade without a fuel system upgrade. Assuming you would have some gains, just not as much as with an upgraded fuel system..
Where would most of the power be? Are you going to see all the power up over the 5-6k rpm?
And would it hurt you 0-3k rpm power??
I'm asking because, if all the extra power is up top and the bottom doesn't see any power or loses some power, this would be a bad mod for a non track daily driver...
Any thoughts would be great..
As far as turbo, I would be looking and the ATP twin turbo upgrade?
Thx
I made all of my power before 5500 RPM even though boost stayed flat across the board.
There's videos and dyno sheets to show where the power was gained in my video I posted.
This is a little behind, but I just read the thread. Anyway, make me smarter please.... Am I right in assuming that the bigger turbo does more because if i compress more air at a time it's more air at the same pressure and because of the volume the pressure (therefore the amount of boost cylinder load) is greater... like having a volume tank on a compressor? That is to say... because more air is more air?
I'm in for an ATP turbo upgrade but want to see the gains with only a tune first.
Someone needs to take the plunge. Just not me!
Quote from: BiGMaC on November 07, 2013, 05:56:11 PM
This is a little behind, but I just read the thread. Anyway, make me smarter please.... Am I right in assuming that the bigger turbo does more because if i compress more air at a time it's more air at the same pressure and because of the volume the pressure (therefore the amount of boost cylinder load) is greater... like having a volume tank on a compressor? That is to say... because more air is more air?
Woah BigM, I read it twice and still not sure I understand your question ;D So waaay oversimplifying it, an engine is an air pump, move more air and make more power. Turbo's move air and send it back inot the motor, lets say one is a syringe and one is a garden hose, if both are flowing water at 10PSI at the tip are needed to fill a five gallon bucket, which one fills the bucket faster, syringe or garden hose?
Reality is that bigger turbo keeps increased air volume consistent and doesn't lose pressure. More air at same PSI makes more power...
Quote from: QuickSilver on November 26, 2013, 10:07:47 PM
Quote from: BiGMaC on November 07, 2013, 05:56:11 PM
This is a little behind, but I just read the thread. Anyway, make me smarter please.... Am I right in assuming that the bigger turbo does more because if i compress more air at a time it's more air at the same pressure and because of the volume the pressure (therefore the amount of boost cylinder load) is greater... like having a volume tank on a compressor? That is to say... because more air is more air?
Woah BigM, I read it twice and still not sure I understand your question ;D So waaay oversimplifying it, an engine is an air pump, move more air and make more power. Turbo's move air and send it back inot the motor, lets say one is a syringe and one is a garden hose, if both are flowing water at 10PSI at the tip are needed to fill a five gallon bucket, which one fills the bucket faster, syringe or garden hose?
But the needle is the same size (intake tubing, throttle, plenum)...
I'm trying to wrap my head around it too.
This is my first experience with turbos, and I'm green as can be.
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I think when the air from the turbo hits the smaller "pipe" size it will increase in velocity and still maintain CFMs. Like a venturi fitting.
That's how I thought about it....... so the larger diameter turbo moves air hitting the same pipe (intake valve) as the smaller one with both at the same pressure. The air must then move faster from the larger turbo in that pipe to be at the same pressure as that from the smaller turbo.Cylinder size is fixed.. so more air (boost) gets into the cylinder (combustion chamber)... I think?
Yeah, I think. It's like water pumps. A bigger pump supplying the same psi on the same size pipe will create higher velocities. And, when you reduce the pipe size it will increase the velocity.
I haven't had the opportunity to dyno my truck with the bigger turbos on it yet but I do know they make more power. I play on occasion on the old hwy that goes by my subdivision, it's flat, straight and you can see for at least two miles in either direction. Before my turbos I was getting 0-60 times of 5.5 sec, now I'm seeing 4.75's
Whoa! That's quite a gain! Must be fun hanging on to.
Is it an f150???
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Yeah, its an F150 super crew with 33" mud terrains on it. I bought a set of stock 17" Xlt wheels that I need to get tires for so I can take it to the track this spring.
Launches are pretty bad ass, I just try not to do the 4x4 too often with these heavy ass tires on here. Its done some clunking here and there, almost like the 4wd wasn't fully engaged.
Also this was done over and over previously and after install, same spot in the stretch of road to try and keep it as consistent as possible.
Way to go! That must translate to 60-75 WHP!
It was a good mod for the money, IMO. Love the look of your SHO Mac, when I was dealing on my truck they had one on the lot that looked similar to yours I was eye balling.
Thanks red... working on a tasteful blackout and the lighting. Getting ready to make it run a bit quicker... maybe not as fast as your ride.. but quicker.
Well from what I can see of the pics in your Sig, you're doing a nice job. I'm sure you'll have no trouble besting my heavy brick when you get into the performance aspect of it, these SHO's are pretty bad.
My truck is black and I've gone with a black/gun metal theme. I need to get the milled part of my wheels done yet and my FX redone (was done before i decided to do gun metal).Had planned on tinting the tails but I just painted the clear edges black which is a subtle but no d changd
Sounds awesome, I'm partial to a black vehicle LOL ...until the show my DD was F150-F350.. Love trucks! Pics please? :please:
My last F150 FX4 was a flame blue and black theme. I did the Heads and tails by replacing them with the black filled SVT raptor version... pure bolt-on change.
I might be iinterested in a turbo upgrade eventually depending on the cost vs performance upgrade benefits, but I don't have the time to be the guinea pig.
I'll get some taken and up soon, its negative something or other out today so wont be doing it today, lol. I haven't really taken many of it other than specific shots of part installs and what not people have requested.