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In hopes that some noob will read ALL the posts in this thread, I am going to have to nerd out here since you missed the point. It is quite possible to make 40psi at 2,000 RPM with an FR RED, BLACK, whatever for an instant, but not sustained. Because boost is only reflective of the inability to move air through an engine. So I am saying that I believe you can make that kind of BOOST at that rpm with an FP RED. But not without hitting surge (and therefore boost will fluctuate), and not while making any power. Every compressor map has a surge line. So over a decade ago I made a spreadsheet to plot flow for 2.0ltr engines based on pressure ratio using some simple inputs. I gave this spreadsheet out so people can calculate if they are exceeding the abilities of a turbo. I did you the favor of entering your 32psi reported boost @2800 rpm (first data point). The results are at the bottom.
SHOW ME ANY TURBO COMPRESSOR MAP IN EXISTENCE that can support a pressure ratio of 3.74 while flowing 20.5 lbs/min of air.
TAKE YOUR PIC: Garrett, Borg, MHI. Any compressor map you want.
Not going to happen.
The FP RED compressor can't do it. When you hit surge the air being forced into the engine stalls on the exit of the compressor and the speed of the shaft falls, then once it lowers the PR under the surge line it regains and happens over and over again rapidly. This is because the flow cannot occur at that pressure ratio. It is also very hard on the thrust bearings and will destroy your turbo. Compressor surge covers alleviate this by providing a path for the pressure to essentially "leak" back into the inlet. The result is no surging in the sense of rapid pressure spikes up/down, and thus saving the thrust bearings....but at the same time it is lowering the boost. So again, 32psi isn't going to happen at 2,800 RPM on a 2.0ltr engine.
Results:
I did not miss any point, your graph does not reflect reality, it just shows what in theory might have happen according to a spreadsheet you made, created based on certain specific parameters you consider to be of as such. You did me no favor here, and everything you have said reflects nothing here but a certain theory, if it can be called that, based on partial and individually used physics knowledge that it is not even neither used or explained properly. You have no idea how much flow can occur in relation to specific pressure ratio so do not try be a wise-*** here by making moronic statements which you expect people to take them for granted. What you have tried to prove here, is exactly what I despise with people trying to play it smart in an effort to dazzle people not in the know. Your input figures on the chart, apart from the 32 psi of boost that I have said have no substantial evidence nor pragmatical existance. As for what surge can do, do not lecture me on it as I have experimented with turbos for more than 20 years and surge of an fp red as it might have happened under the situation I described will not damage in any way a journal bearing fp red. Also if we wanted to isolate the surge phenonemon, then we would need to bring into discussion, external factors that are immediately connected with it, such as elevation-ambient temperature- molecular density-humidity. A TD05H-15GK2-9.0 turbo has full boost of 2bar at 2K rpm on a well prepared group N engine without any surge issues whatsoever. The fp red compressor which has a "smoother operation" meaning a smoother pressure ratio and flow delivery at the particular rpm/boost combo due to its size compared to the above mentioned turbo is perfectly capable of pushing the specific cfm at the specific pressure ratio as I have described. No boost fluctuation/surge whatsoever. Rarely do well built turbos get damaged by surge, there are many oem turbo models of cars out there from various manufactarers that are surging throughout their entire life but are still running strong. And since we mentioned bearings, for the record I was using a dual ball bearing fp red.
Besides doing all the above, another very important point here is that you have isolated the turbo and tried with false numbers and so called "theoretical evidence" to focus on just the turbo and not on the entire setup including mapping, where things like full boost and surge are things that can be manipulated and alleviated.
Get it through your head right, this can be done and a very descent amount of power can be achieved out of it. You will not be able to get the maximum flow/lbs out of the turbo and power out of your setup but the use of the right parts the right way and the trade-off will be done to the minimum. Setting up your fp red setup this way will make a very good amount of early torque which is the most essential for track/circuit/ time attack/rally driving.
Marios
Last edited by Evo8cy; Dec 5, 2015 at 04:29 AM.
Reason: typo
I like seeing how theoretical and actual results vary in real world conditions. Now I would like to see a log of how quick that Red spools(maybe they were posted somewhere?).
To his credit, he didn't say he made power, just that he did it. I didn't even think it was possible. I stand corrected.
there is a slight point in what Marios is saying actually and that is that boost is also a factor of the cam lift and timing, i.e. cam overlap...
If you run high duration - overlap cams you will have a point in the lower rpm where your intake air just goes trough the cylinder and out into the exhaust... At that point the turbo, already not getting enough energy from the exhaust, has an open hole in the intake and there is no possibility to produce boost in the intake..
Now, if you get some short duration cams and play with the individual cam timing to get much less overlap, it will be relatively easy to get boost in the intake manifold...
Now, completely opposite question is if it has any value whatsoever.. and this is where Marios input on his fp red making boost low down has no value to this discussion... because what OP needs is usable torque/power at lower RPM for track work.. not simple boost.
Things to have in mind.. Most of european dynos are eddy current ones and have somewhat long sweep times.. also some tuners tend to hold the engine under full load for a couple of sec when they start the run... Maha RR dynos have notoriously long runs... In other words, they all can play with boos thresholds on the dyno and that doesnt reflect the real world. (part of why I like VD).
Also, if you just tune the engine for early boost, maybe you are loosing some power low down because you can get boost early by retarding the timing too..
there is a slight point in what Marios is saying actually and that is that boost is also a factor of the cam lift and timing, i.e. cam overlap...
Cam dialing is of the utmost essence when it comes to manipulating the power curve, boost thresholds and the overall behaviour of a turbocharger.
If you run high duration - overlap cams you will have a point in the lower rpm where your intake air just goes trough the cylinder and out into the exhaust... At that point the turbo, already not getting enough energy from the exhaust, has an open hole in the intake and there is no possibility to produce boost in the intake..
Now, if you get some short duration cams and play with the individual cam timing to get much less overlap, it will be relatively easy to get boost in the intake manifold...
Its is not only simply a matter of manipulalting overlap, but using the right camshafts with the right profile characteristics. These two factors are equally important. Also other factors come into place, such as the intercooler used, piping, exhaust manifold, wastegate/boost control setup.
Now, completely opposite question is if it has any value whatsoever.. and this is where Marios input on his fp red making boost low down has no value to this discussion... because what OP needs is usable torque/power at lower RPM for track work.. not simple boost.
If boost was not the necessary ingredient in the generation of more torque people would not be using forced induction engines, they would stick to aspirated ones. Boost and torque are interrelated. As long as flow is in accordance, the earlier you make boost the earlier you will make torque. The more boost you make down low the more torque you make. WRC and rally cars in general are the finest example of this.
Things to have in mind.. Most of european dynos are eddy current ones and have somewhat long sweep times.. also some tuners tend to hold the engine under full load for a couple of sec when they start the run... Maha RR dynos have notoriously long runs... In other words, they all can play with boos thresholds on the dyno and that doesnt reflect the real world. (part of why I like VD).
Also, if you just tune the engine for early boost, maybe you are loosing some power low down because you can get boost early by retarding the timing too..
Leave dynos out of this thread, they have no place here, Dynos are tuning tools nothing more nothing less, apart from the differences of one type of dyno to another, they can be manipulated to give almost any desired outcome.
Obviously the O/P here is interested in creating a rally/time attack type of setup.
As far as the logs are concerned, I will repeat myself once more, the fp red setup was 5+ years ago and I do not keep logs on the hardrive when mapping and a setup is finished, so there will be no log posting. I might still have an in car video though I did back in '09 on the fp red setup with 1-4th pulls and a couple of high gear, 4th and 5th, low rpm highway pulls. If I find the video and it has not been deleted that is, I will upload to photobucket and post the link on here.
We are all here to learn, and I only post stuff I have done and learned, no point in posting anything else than that.
Something completely irrelevant, Croatia is a beautiful country with beautiful women
Leave dynos out of this thread, they have no place here, Dynos are tuning tools nothing more nothing less, apart from the differences of one type of dyno to another, they can be manipulated to give almost any desired outcome.
it does have a place in the discussion if a different type of dyno has something to do with how the car is boosting so much at such a low RPM.
it does have a place in the discussion if a different type of dyno has something to do with how the car is boosting so much at such a low RPM.
You should be interested in what your setup can do on the road, not on a certain dyno. The ambient conditions and road loading differ greatly than that of any dyno, no matter how close the simulation tries to be. Secondly the figures I posted have all to do with the road and nothing with a dyno. A dyno should matter to you as a tuning tool and as way to compare previous setups to newer ones, or to make sure corrections/alterations you have done have actually affected you setup as expected and then compare what you have done on the dyno with actual either road driving or track driving depending of what your intented use of the car was.
You should always use the same dyno on the same settings, and try to find similar ambient conditions, when you re-use it to so as the comparison to be as accurate as possible. Other than this, it is like comparing apples to peaches, they are both fruit but totally different in all aspects.
As a rule of thumb, but not absolute by any means, on the road you will see an earlier boost threshold, spool time, and full boost rpm point than on the dyno.
I have worked for over a decade as a software engineer writing code to calculate flow/pressure systems for nuclear reactors; including FLOW throw centrifugal pumps at pressure. I am not trying to dazzle, but rather provide some factual engineering to what appears to be a magical data point.
This thread is a great example of why I am so infrequent on these forums. If hard engineering factual calculations do not hold water; then I am done.
But not quite yet.
In my library I have "Street Turbocharging" by Mark Warner P.E. Chapter 4 is on compressors.
To find if a compressor can meet your goal you need to calculate PR (page 37).
PR is pressure ratio. You provided a boost of 32psi at an RPM 2,800.
14.7 psi - is known standard for pressure of the atmosphere AT SEA LEVEL (favorable)
13.9 psi - is FAVORABLE pressure loss (link below used less favorable 13.7)
1psi - is the GREAT low pressure drop for the intercooler, hard to beat. Again favorable.
So the numbers I put in the spreadsheet were in your favor. Even the VE for the engine is sitting at a nice [1.0] or 100% efficient engine! A nice 75deg day outside!
Anyhow:
PR(compressor) = (32psi + 1psi + 14.7psi) / 13.9
This provides a PR of 3.374 which was shown in my spreadsheet at cell D-33. In the forum text I dyslexic translated this to 3.74. My apologies. It doesn't actually make a difference.
We know the FP Red compressor specs are: 54.8MM Inducer / 76MM Exducer
This is from the FP website. So it is fair to compare it to the BIG TWO (Borg, Garrett) 76mm compressors they make.
Sticking with our calculated pressure ratio of 3.374 we can pull up some compressor maps:
Draw a line across horizontal in your mind at 3.37.
Garrett GTX3076
BORGW 7670
I am not going to break down calculating flow, but cell A-33 shown in my previous post has the equation [ =(((C7+B7)/(53.3*12*(460+130)))*(122.05*G7))/(2*F7)]
This relates to a flow rate of 20.7lb/min.
This is covered in "Street Turbocharging" by Mark Warner P.E. Chapter 4 page 38 and 39.
You now plot your PR and your flow on the compressor map. If its OFF THE MAP then you are past the surge point and it CANNOT DO IT. The air flow stalls. It's just a fact of life. Sorry. Neither the BORG 76mm compressor NOR Garrett 76mm compressor can operate at this region. The FP RED is not made of fairy dust, which is why everyone who has had experience with it has not seen this operating point (32psi @ 2,800 RPM). It doesn't matter on tuning or cams or anything.
Secondly the figures I posted have all to do with the road and nothing with a dyno.
Marios
thanks for clarifying.
Originally Posted by Evo8cy
As a rule of thumb, but not absolute by any means, on the road you will see an earlier boost threshold, spool time, and full boost rpm point than on the dyno.
not if someone was using a different type of dyno that affects the car differently than we're used to.
not if someone was using a different type of dyno that affects the car differently than we're used to.
No worries on the clarification, and yes you are correct on the different dyno usage, hence why it only matters what lap times you make or how the car behaves on the road.
I have worked for over a decade as a software engineer writing code to calculate flow/pressure systems for nuclear reactors; including FLOW throw centrifugal pumps at pressure. I am not trying to dazzle, but rather provide some factual engineering to what appears to be a magical data point.
This thread is a great example of why I am so infrequent on these forums. If hard engineering factual calculations do not hold water; then I am done.
But not quite yet.
In my library I have "Street Turbocharging" by Mark Warner P.E. Chapter 4 is on compressors.
To find if a compressor can meet your goal you need to calculate PR (page 37).
PR is pressure ratio. You provided a boost of 32psi at an RPM 2,800.
14.7 psi - is known standard for pressure of the atmosphere AT SEA LEVEL (favorable)
13.9 psi - is FAVORABLE pressure loss (link below used less favorable 13.7)
1psi - is the GREAT low pressure drop for the intercooler, hard to beat. Again favorable.
So the numbers I put in the spreadsheet were in your favor. Even the VE for the engine is sitting at a nice [1.0] or 100% efficient engine! A nice 75deg day outside!
Anyhow:
PR(compressor) = (32psi + 1psi + 14.7psi) / 13.9
This provides a PR of 3.374 which was shown in my spreadsheet at cell D-33. In the forum text I dyslexic translated this to 3.74. My apologies. It doesn't actually make a difference.
We know the FP Red compressor specs are: 54.8MM Inducer / 76MM Exducer
This is from the FP website. So it is fair to compare it to the BIG TWO (Borg, Garrett) 76mm compressors they make.
Sticking with our calculated pressure ratio of 3.374 we can pull up some compressor maps:
Draw a line across horizontal in your mind at 3.37.
Garrett GTX3076
BORGW 7670
I am not going to break down calculating flow, but cell A-33 shown in my previous post has the equation [ =(((C7+B7)/(53.3*12*(460+130)))*(122.05*G7))/(2*F7)]
This relates to a flow rate of 20.7lb/min.
This is covered in "Street Turbocharging" by Mark Warner P.E. Chapter 4 page 38 and 39.
You now plot your PR and your flow on the compressor map. If its OFF THE MAP then you are past the surge point and it CANNOT DO IT. The air flow stalls. It's just a fact of life. Sorry. Neither the BORG 76mm compressor NOR Garrett 76mm compressor can operate at this region. The FP RED is not made of fairy dust, which is why everyone who has had experience with it has not seen this operating point (32psi @ 2,800 RPM). It doesn't matter on tuning or cams or anything.
I am not a software engineer, I am not an engineer of anysort, I am just a gearhead mechanic and school teacher who everything he has learned on engineering in general, either that be on jet engines or on internal combustion ones, has done it through reading/studying and through hard proof pragmatical experience of 20+ years. To give you an example, I designed on a piece of paper in 2000 the gtx 11 blade wheel which Garrett brought out a few years later. Had I the resources to have that cut out billet, of forged T6 7075 aluminum I would have replaced that compwheel on that big turbonetics turbo I used on a Supra. I have numerous times seen compressor wheels and turbochargers operate in the off the map area where the so called either surge or choke point are, and in reality they perform much differently than what their compressor maps dictate. Know that you should take the compressor maps brought out by companies with a grain of salt as they are mostly a base map based on general testing and readings, and many times are way off. This is what actual application to reality has shown me. Reality differs greatly from theory, not just in turbochargers but in many other fields of science or of any other aspect of life.
I already know how to calculate PR, which is the ratio of the air total pressure pt exiting the compressor to the air pressure entering the compressor, and flow for any given compressor.
Also if you want to use your software accurately, since you believe that will you give you the right knoweldge on the fp red you really need to have its actual compressor map.
Oh and the tuning part, has A LOT of impact and dictates greatly the behaviour and output performance of a compressor wheel, or more accurately a turbochanger. Apart from my commenting on the compressor maps, never judge the output and performance characteristics of a turbocharger based on just the compressor map, you see it does not work on its own in there, but in conjuction
with another compressor called turbine wheel.
Other than this I see not point in discussing the subject.
of entering your 32psi reported boost @2800 rpm (first data point). The results are at the bottom.
on the different dyno usage, hence why it only matters what lap times you make or how the car behaves on the road.