What turbo to achieve 350bhp?
- Thread starter srankin90
- Start date
sx_turbo
Lifer
only good for track
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Gord, on a 4e with a stock cylinder head and a 7200rpm rev limit, it will flow fine at 1 bar, and will make 1 bar of boost just before 3600rpm.
On a 4e with a stock cylinder head and a 7200 rpm rev limit, it will flow 2 bar easily, and will make this boost at about 3800rpm.
Seems like a good turbo to me, sounds good for track
On a 4e with a stock cylinder head and a 7200 rpm rev limit, it will flow 2 bar easily, and will make this boost at about 3800rpm.
Seems like a good turbo to me, sounds good for track
Yeah the 2860 will be more suited even for road use it's not bad, my mates td04 glanza doesn't start to spool till like 3200rpm, so the bigger punch is worth the wait :haha:
Couldn't say the power level it will give as it depends on many things, but I would say 360-380bhp is achievable at high boost.
Couldn't say the power level it will give as it depends on many things, but I would say 360-380bhp is achievable at high boost.
Gord R
Member +
http://www.facebook.com/media/set/?set=a.10151231299970103.821758.46944410102&type=3
Looks like it shouldn't be too long till they hit the market.
Looks like it shouldn't be too long till they hit the market.
Gord, on a 4e with a stock cylinder head and a 7200rpm rev limit, it will flow fine at 1 bar, and will make 1 bar of boost just before 3600rpm.
On a 4e with a stock cylinder head and a 7200 rpm rev limit, it will flow 2 bar easily, and will make this boost at about 3800rpm.
Seems like a good turbo to me, sounds good for track
2bar by 3800rpm?? that is mad!!
Rory
Lifer
Within 200rpm you will gain 1 bar.........? Doubtfull.
Gord, on a 4e with a stock cylinder head and a 7200rpm rev limit, it will flow fine at 1 bar, and will make 1 bar of boost just before 3600rpm.
On a 4e with a stock cylinder head and a 7200 rpm rev limit, it will flow 2 bar easily, and will make this boost at about 3800rpm.
Seems like a good turbo to me, sounds good for track
I am also wondering?
It was just an estimate for a quick read off the flow map.
But for those that are interested i'll do a little tutorial on how to read a flow map.
Although I will like to say that the formula used is not my own, its from a well respected tuner A.Graham Bell and his book Forced induction peformance tuning.
Everything on a flow map is an estimate, nothing is set in stone, there are too many factors to consider to how a turbo will spool or what air it will flow. Things like compression ratio, air density, air temperature, even right down to the material of the intercooler pipes, all of these things will affect the CFM, unless you use a manometer to measure the pressure drop at various points in the inlect tract you will only EVER get an estimate answer. Since I don't have the use of a flow bench these calculations will be estimated.
Lets take the GTX2860R turbocharger that Gord R posted a picture of the compressor flow map.
Now we need to determine the pressure ratio of the turbocharger. This is the forumla for calculating the pressure ratio PR= Gauge Pressure+Absoulte pressure/Absoulte Pressure.
Ok lets plug some numbers in this formula, so for starters we want to run 1 bar of boost pressure.
PR = 1 bar (Gauge)+ 1 bar(Absolute)/ 1 bar (Absolute)
So our Pressure Ratio= 2
Now we want to calculate the CFM, so we are going to use this formula:
CFM= (L*RPM*VE*PR)/5660
Where L= Engine capacity in litres
RPM= Rev limit
VE=Volumetric Efficiency
PR= Pressure ratio
For the volumetric efficiency for a stock 4 valve per cylinder, is 90%, we can already see that this is going to be an estimate as unless the cylinder head is flow tested on a bench the results may vary, likely to be upto about 4% either way.
For a slightly modified cylinder head the VE we are going to use is 93% and for a competition cylinder head with fully worked chambers, cams etc the VE is 105%.
Ok so lets plug some numbers into this formula:
CFM=(1.331* 7200*90*2)/5660
CFM=304.76 CFM
So now since our compressor flow map doesn't show us CFM but instead shows us lbs/min, we need to divide our answer by 14.27. So once this is done we end up with a value of:
lbs/min= 21.35
Since its going to be really hard to read this figure off we will round the number down to 21 lbs/min.
So now we have two values and we can plot this on our compressor flow map
So now we can clearly see that our GTX2860R turbocharger will flow 1 bar of boost pressure and will be in the 76% efficiency island.
Now we want to see where the turbo will start spooling a this boost pressure, so we go back to our CFM formula, but instead change the RPM to half the rev limit, so for this case half of our 7200rpm rev limit will be 3600rpm. Then we can check to see if we will make full boost by then.
CFM= (1.331*3600*90*2)/5660
CFM=152.38
And now in lbs/min- 152.38/14.27
lbs/min=10.67
Again since this is going to be hard to read off our flow map we will round this one UP since we rounded our last figure down. By alternating the rounding we will cancel out any errors. So this one goes to 10.1 lbs/min
Now lets plot this figure on our flow map
Here we can see that at this boost pressure we will JUST about spool this turbo at 3600rpm as it is just to the right of the surge line and is in the 67% efficiency island.
So now lets take a slightly modified cylinder head at the same boost pressure:
CFM= (1.331*7200*93*2)/5660
CFM= 314.92
lbs/min= 22.06 round this to 22.0
Already we can see that a slightly modified cylinder head is flowing more air at the same boost pressure, although its not much, its still more, and we will clearly see this when we come to looking at the spool.
Now what we want to see if this modified cylinder head has made any difference to our spool time.
CFM=(1.331*3600*93*2)/5660
CFM= 157.46
lbs/min=11.03 round this to 11 lbs/min
Now lets plot this on our flow map and see if it has affected our spool
Here we can clearly see straight away that we will spool a little faster at the same boost pressure with our modified cylinder head. The intersection point now is clearly seen to the right of the surge line whereas before we was struggling to see the intersection point on the flow map.
What about if we increase the boost pressure? Well lets take a look!
First we need to calculate the Pressure ratio again:
PR= 2 bar (gauge)+1 bar (Absolute)/ 1 bar (Absolute)
PR= 3
Now lets calculate our CFM at 2 bar of boost pressure at a rev limit of 7200rpm and stock 4 valve cylinder headto keep consistent with our previous calculations
CFM= (1.331*7200*90*3)/5660
CFM= 457.14
lbs/min= 32.03 But lets round this to 32lbs/min
Now to plot this on our flow map gives:
Now this is starting to look like a very good turbo with big power capabilites!
Even at 2 bar of boost pressure we are in the 76% efficiency island and with the possiblity of flowing even more boost pressure with ease.
So now lets take a look to see when this turbocharger is going to spool at 2 bar of boost pressure by taking half of our rev limit to see if it will spool here.
Again we calculate our CFM:
CFM= (1.331*3600*90*3)/5660
CFM= 228.57
lbs/min= 16.01 lets round this to 16.0 lbs/min
Now to plot these figures on our flow map.
Here we can see that this turbo will not spool our 2 bar full boost by 3600rpm its way before the surge line.
So now lets calculate where this turbo will make 2 bar full boost, lets take 3800rpm as a point to pick.
CFM= (1.331*3800*90*3)/5660
CFM= 241.27
lbs/min= 16.90 lets round this to 17 lbs/min
And now we can plot these points on our flow map again.
Looks like we still won't make 2 bar boost at 3800rpm, lets try more than a 200rpm increment, lets test it at 4200rpm.
CFM= (1.331*4200*90*3)/5660
CFM= 266.67
lbs/min= 18.68 lets round this to 19 lbs/min and plit on our flow map again...
We are just inside the surge line at 4200rpm running 2 bar of boost, so this indicates that the GTX2860R will spool 2 bar at 4200rpm on a stock 4 valve cylinder head.
Now this can be done with any turbocharger, once you do a few flow maps you will get the hang of it and its not a long process to do. You can quickly look and read off where the turbocharger will spool and how much air it will flow.
I would like to stress again that this is only an estimate! Everyones engine is slightly different in one way or another.
But for those that are interested i'll do a little tutorial on how to read a flow map.
Although I will like to say that the formula used is not my own, its from a well respected tuner A.Graham Bell and his book Forced induction peformance tuning.
Everything on a flow map is an estimate, nothing is set in stone, there are too many factors to consider to how a turbo will spool or what air it will flow. Things like compression ratio, air density, air temperature, even right down to the material of the intercooler pipes, all of these things will affect the CFM, unless you use a manometer to measure the pressure drop at various points in the inlect tract you will only EVER get an estimate answer. Since I don't have the use of a flow bench these calculations will be estimated.
Lets take the GTX2860R turbocharger that Gord R posted a picture of the compressor flow map.
Now we need to determine the pressure ratio of the turbocharger. This is the forumla for calculating the pressure ratio PR= Gauge Pressure+Absoulte pressure/Absoulte Pressure.
Ok lets plug some numbers in this formula, so for starters we want to run 1 bar of boost pressure.
PR = 1 bar (Gauge)+ 1 bar(Absolute)/ 1 bar (Absolute)
So our Pressure Ratio= 2
Now we want to calculate the CFM, so we are going to use this formula:
CFM= (L*RPM*VE*PR)/5660
Where L= Engine capacity in litres
RPM= Rev limit
VE=Volumetric Efficiency
PR= Pressure ratio
For the volumetric efficiency for a stock 4 valve per cylinder, is 90%, we can already see that this is going to be an estimate as unless the cylinder head is flow tested on a bench the results may vary, likely to be upto about 4% either way.
For a slightly modified cylinder head the VE we are going to use is 93% and for a competition cylinder head with fully worked chambers, cams etc the VE is 105%.
Ok so lets plug some numbers into this formula:
CFM=(1.331* 7200*90*2)/5660
CFM=304.76 CFM
So now since our compressor flow map doesn't show us CFM but instead shows us lbs/min, we need to divide our answer by 14.27. So once this is done we end up with a value of:
lbs/min= 21.35
Since its going to be really hard to read this figure off we will round the number down to 21 lbs/min.
So now we have two values and we can plot this on our compressor flow map
So now we can clearly see that our GTX2860R turbocharger will flow 1 bar of boost pressure and will be in the 76% efficiency island.
Now we want to see where the turbo will start spooling a this boost pressure, so we go back to our CFM formula, but instead change the RPM to half the rev limit, so for this case half of our 7200rpm rev limit will be 3600rpm. Then we can check to see if we will make full boost by then.
CFM= (1.331*3600*90*2)/5660
CFM=152.38
And now in lbs/min- 152.38/14.27
lbs/min=10.67
Again since this is going to be hard to read off our flow map we will round this one UP since we rounded our last figure down. By alternating the rounding we will cancel out any errors. So this one goes to 10.1 lbs/min
Now lets plot this figure on our flow map
Here we can see that at this boost pressure we will JUST about spool this turbo at 3600rpm as it is just to the right of the surge line and is in the 67% efficiency island.
So now lets take a slightly modified cylinder head at the same boost pressure:
CFM= (1.331*7200*93*2)/5660
CFM= 314.92
lbs/min= 22.06 round this to 22.0
Already we can see that a slightly modified cylinder head is flowing more air at the same boost pressure, although its not much, its still more, and we will clearly see this when we come to looking at the spool.
Now what we want to see if this modified cylinder head has made any difference to our spool time.
CFM=(1.331*3600*93*2)/5660
CFM= 157.46
lbs/min=11.03 round this to 11 lbs/min
Now lets plot this on our flow map and see if it has affected our spool
Here we can clearly see straight away that we will spool a little faster at the same boost pressure with our modified cylinder head. The intersection point now is clearly seen to the right of the surge line whereas before we was struggling to see the intersection point on the flow map.
What about if we increase the boost pressure? Well lets take a look!
First we need to calculate the Pressure ratio again:
PR= 2 bar (gauge)+1 bar (Absolute)/ 1 bar (Absolute)
PR= 3
Now lets calculate our CFM at 2 bar of boost pressure at a rev limit of 7200rpm and stock 4 valve cylinder headto keep consistent with our previous calculations
CFM= (1.331*7200*90*3)/5660
CFM= 457.14
lbs/min= 32.03 But lets round this to 32lbs/min
Now to plot this on our flow map gives:
Now this is starting to look like a very good turbo with big power capabilites!
Even at 2 bar of boost pressure we are in the 76% efficiency island and with the possiblity of flowing even more boost pressure with ease.
So now lets take a look to see when this turbocharger is going to spool at 2 bar of boost pressure by taking half of our rev limit to see if it will spool here.
Again we calculate our CFM:
CFM= (1.331*3600*90*3)/5660
CFM= 228.57
lbs/min= 16.01 lets round this to 16.0 lbs/min
Now to plot these figures on our flow map.
Here we can see that this turbo will not spool our 2 bar full boost by 3600rpm its way before the surge line.
So now lets calculate where this turbo will make 2 bar full boost, lets take 3800rpm as a point to pick.
CFM= (1.331*3800*90*3)/5660
CFM= 241.27
lbs/min= 16.90 lets round this to 17 lbs/min
And now we can plot these points on our flow map again.
Looks like we still won't make 2 bar boost at 3800rpm, lets try more than a 200rpm increment, lets test it at 4200rpm.
CFM= (1.331*4200*90*3)/5660
CFM= 266.67
lbs/min= 18.68 lets round this to 19 lbs/min and plit on our flow map again...
We are just inside the surge line at 4200rpm running 2 bar of boost, so this indicates that the GTX2860R will spool 2 bar at 4200rpm on a stock 4 valve cylinder head.
Now this can be done with any turbocharger, once you do a few flow maps you will get the hang of it and its not a long process to do. You can quickly look and read off where the turbocharger will spool and how much air it will flow.
I would like to stress again that this is only an estimate! Everyones engine is slightly different in one way or another.
BallıGee
Member +
What will the tial ex housing add to these figures Adam
http://www.tialsport.com/prod ss turbo.html
http://www.tialsport.com/prod ss turbo.html