I wonder how much less pressure it would need to reach the same power level if the engine had a fully ported head with cams.
BMW N54 335i AT Speedtech 1025PS/1011HP-1225Nm/903.5ftlb
- Thread starter Scorpstan
- Start date
I should not do this but.... some bmep calculations shows that there is something odd in that dyno sheet.
These engines on stock head with torque max at 5900rpm should have bmep value in a level of prox 12 plus charge air increases what in this case should be 12x3.4(abs at 35psi)x1.07(effect of e85 cooling) minus some degree charge air temp rise and ignition advance pulls on that boost levels.
Calculator shows bmep with e85 should be at best possible ideal situation in a level of 40-42. Now that dyno show values over 51.5
Is there any explanations to this? 200-250hp nitrous shot could explain it.
Just qurious and waiting to see some logs of this.
These engines on stock head with torque max at 5900rpm should have bmep value in a level of prox 12 plus charge air increases what in this case should be 12x3.4(abs at 35psi)x1.07(effect of e85 cooling) minus some degree charge air temp rise and ignition advance pulls on that boost levels.
Calculator shows bmep with e85 should be at best possible ideal situation in a level of 40-42. Now that dyno show values over 51.5
Is there any explanations to this? 200-250hp nitrous shot could explain it.
Just qurious and waiting to see some logs of this.
Yes, flywheel but still odd value in bmep calculations. Head is still designed in runner size to maximize torque at some 2500-3500 level and for sure it will cut bmep at 5900 much lower. At that 2500 these engines manage to do over 13 bmep values but stock head and 5900, this should hit values less than 12 even with open exhaust and very small exhaust back pressure, notice that pte6870 is way over it's peak effiency at those levels so it will push charge air temp up too.
This hit now value of 15.1 calculated as a atm what is in a terroritory of a F1 engine and that is freakin high.
What is lifting bmep is
- high compressin ratio, not in this case
- short stroke, big piston what equal to big valves, not in this case
- stupidly well flowing head, not in this case
- intake manifold runner size matched for rpm this level, yes in this case
- very low exhaust back pressure, not in this case even with big turbine housing
Stock engine at these 5900rpm ratios has 15.1 bmep with boost 0.5bar so as atm that will produce only bmep of 10 at those rpm's
So calculations with 12 throw it with 35psi to value of that same 40 area what ever you do, not in those insanne 51.5.
That's why it could be interested to see logs of this run.
And as a reference, my 135 runned with stock head over 172mph 1/2 miles at close to 30psi .. with 630 at the wheel so this should be in a 670-700 true whp level at the wheel with that 178.
That bmep calculation give very rough runs to many dynoruns, cause of that it's narrow line where every single engine should hit on and it just calculate volumetric effiency.
Remember that on last 50 years, ve and therefore bmep has been improved by only some 15-20%, with all gizmos there has been throwed to development of combustion engines... multivalves.. vanos.. valvetronic.. electronic.. injection.. intake design.. controlled burn process, you name it.. i think of that improvement is due much more precise electronic control and other half is improved cylinder fill by mechanical things.
So at mechanical side we have done improvement from 12 to 13.5 in average bmep in last 50 years
My 2cents
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no NOS. just E85 and wmi.
it is what it is. put the calculator by side and go on street.
logs of course secret. take a look on my WR on 1.2 mile with 900hp crank. that explain all
I just told that i could be interested on the technic how to archieve this over 51 bmep with the specs what was on the sheet.
Bmep value as i told is a upper limit where you can reach with different combinations and it's very easy to do calculations about where you are in point of view as mathematic calculations.
As stock engine, 3 liter, 400nm, 5900rpm, 0.5bar boost equal to prox 15as bmep.
That bmep is following
Most restrictions on that engine in that level is cylinder head and exhaust manifold with turbine housings.
Take that housing restriction away with much bigger turbo and you are in level of 11 on those rpm ratings as atmo or so, propably maximum what can be archieved with all possible vanos tweaks etc is as atmo at the level of 11.5 and level of 38-39 with 35psi of boost and little more with e85, maybe 41-42 at the extreme end.
Not to go to any ad hominem behaving, just explain how to archieve levels over 51.5 with stock head at rpm ratings way over stock engine max hp rpm level.
Very easy way to get idea of bmep and how easy it is to push it to those levels.
About those performance levels, i archieved with my 135i 276kph 1/2mile with 630whp and 312kph standing mile at power level of 590whp so what of that is not doable? That level of performance throw my car to 10.4/218kph at rev limiter.
And yes, stock internal unopened engine, now i have fully built one and have struggle with misfires.
1/8 trap speed with this combo is over 180kph and that is with prox 700whp.
All of those is arcieved on airport runway without traction additives
So, pleace, read my reply, do some research about bmep calculations and don't start with any ad hominems.
Ps. Matchbot caclulation to stock head n54 @ 35psi
Pps. Played little more with matchbot, some evaluation with wmi
Bmep value as i told is a upper limit where you can reach with different combinations and it's very easy to do calculations about where you are in point of view as mathematic calculations.
As stock engine, 3 liter, 400nm, 5900rpm, 0.5bar boost equal to prox 15as bmep.
That bmep is following
Most restrictions on that engine in that level is cylinder head and exhaust manifold with turbine housings.
Take that housing restriction away with much bigger turbo and you are in level of 11 on those rpm ratings as atmo or so, propably maximum what can be archieved with all possible vanos tweaks etc is as atmo at the level of 11.5 and level of 38-39 with 35psi of boost and little more with e85, maybe 41-42 at the extreme end.
Not to go to any ad hominem behaving, just explain how to archieve levels over 51.5 with stock head at rpm ratings way over stock engine max hp rpm level.
Very easy way to get idea of bmep and how easy it is to push it to those levels.
About those performance levels, i archieved with my 135i 276kph 1/2mile with 630whp and 312kph standing mile at power level of 590whp so what of that is not doable? That level of performance throw my car to 10.4/218kph at rev limiter.
And yes, stock internal unopened engine, now i have fully built one and have struggle with misfires.
1/8 trap speed with this combo is over 180kph and that is with prox 700whp.
All of those is arcieved on airport runway without traction additives
So, pleace, read my reply, do some research about bmep calculations and don't start with any ad hominems.
Ps. Matchbot caclulation to stock head n54 @ 35psi
Pps. Played little more with matchbot, some evaluation with wmi
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It's inhouse built and i don't think it has anything to do with the build.
I opened there on troubleshoot a discussion about n54 misfire issues
@135boost
You're (most) overlooked the part about this being a crank number. But remember the car was on a chassis dyno. So it's whatever conversion they are fudging that's the problem here. It's pretty obvious there is a 'hey look at me' factor here that is made up.
The car is quick. No argument there. But it's nothing groundbreaking.
You're (most) overlooked the part about this being a crank number. But remember the car was on a chassis dyno. So it's whatever conversion they are fudging that's the problem here. It's pretty obvious there is a 'hey look at me' factor here that is made up.
The car is quick. No argument there. But it's nothing groundbreaking.
That is for sure true, the car is quick, nothing to argue about.
I just could get those numbers match even close to any decent calculations and yes,
I'm well aware that this was chassis dyno and crank hp.
That 1225nm @ 5900 is still silly high at 35psi and stock head.
Try to undestand what bmep is all about and how difficult it's to rise it because there is limitations
on a internal combustion engine. Volumetric effiency is one, fuel knock sensitivity other, piston speed vs burn speed, flow speeds in intake and exhaust.. on a atmo engine, volumetric effiency is difficult to get over 105% at maximum torcue rpm and on a very high comp ratio like13-14:1 that equal to some 115-120Nm/l. Every point of reduction in comp ratio decrease that torque by some 4%. That 14 comp ratio with stupidly good flowing head throw bmep to levels over 15.
Those kind of numbers is to be found in modern superbikes and cars like ferrari 458.
That 10.2 what n54 uses put these in level of 13 as atmo at the best possible torque rpm, some 2500 what is calculated on size of intake runner and flow speed. At level of 5900 that ve is in a level of prox 80 estimated from stock engine dyno plot
That can maybe be increased to level of 90 with very good turbo match, like this pte6870.
That 90 mean as bmep 11.5.
Then there is some "simple" but close enough calculations to do about boost and effect on ve/bmep increase.
11.5 bmep x boost pressure of 2.4 is 3.4 abs so we land somewhere in a region of 39. Every 3 degree of iat increase over 20c is decrease that by 1% and for sure there is some kind of iat increase, assume this keep it under 30c so 3%.
This all is calculated without any ignition pulls and quite ideal afr.
Then fuel swap to e85, maximum power increase trough iat decrease can at max increase that outcome by 7%.
So as mathematic point of view, much over 41 as bmep must be explained some way, like secret log, nos, nitromethane blend fuel or something else.
With simple mathematics, you should get calculated values to match quite stupidly close to reality, and surpricely, that matchbot hit those numbers quite close too, just be fair enough with that ve what can be as high as 105 in a that 2500-3500rpm levels in these n54 on stock head/valvetrain. There is possiblity to increase that to a level of 5500-6000 with fully ported head and bigger cams. On stock head, don't put there much over 85 as ve at those 6000plus rpm's.
Have a nice time playing with matchbot, easy, quite accurate and very easy to use
Me and my 2cents
I just could get those numbers match even close to any decent calculations and yes,
I'm well aware that this was chassis dyno and crank hp.
That 1225nm @ 5900 is still silly high at 35psi and stock head.
Try to undestand what bmep is all about and how difficult it's to rise it because there is limitations
on a internal combustion engine. Volumetric effiency is one, fuel knock sensitivity other, piston speed vs burn speed, flow speeds in intake and exhaust.. on a atmo engine, volumetric effiency is difficult to get over 105% at maximum torcue rpm and on a very high comp ratio like13-14:1 that equal to some 115-120Nm/l. Every point of reduction in comp ratio decrease that torque by some 4%. That 14 comp ratio with stupidly good flowing head throw bmep to levels over 15.
Those kind of numbers is to be found in modern superbikes and cars like ferrari 458.
That 10.2 what n54 uses put these in level of 13 as atmo at the best possible torque rpm, some 2500 what is calculated on size of intake runner and flow speed. At level of 5900 that ve is in a level of prox 80 estimated from stock engine dyno plot
That can maybe be increased to level of 90 with very good turbo match, like this pte6870.
That 90 mean as bmep 11.5.
Then there is some "simple" but close enough calculations to do about boost and effect on ve/bmep increase.
11.5 bmep x boost pressure of 2.4 is 3.4 abs so we land somewhere in a region of 39. Every 3 degree of iat increase over 20c is decrease that by 1% and for sure there is some kind of iat increase, assume this keep it under 30c so 3%.
This all is calculated without any ignition pulls and quite ideal afr.
Then fuel swap to e85, maximum power increase trough iat decrease can at max increase that outcome by 7%.
So as mathematic point of view, much over 41 as bmep must be explained some way, like secret log, nos, nitromethane blend fuel or something else.
With simple mathematics, you should get calculated values to match quite stupidly close to reality, and surpricely, that matchbot hit those numbers quite close too, just be fair enough with that ve what can be as high as 105 in a that 2500-3500rpm levels in these n54 on stock head/valvetrain. There is possiblity to increase that to a level of 5500-6000 with fully ported head and bigger cams. On stock head, don't put there much over 85 as ve at those 6000plus rpm's.
Have a nice time playing with matchbot, easy, quite accurate and very easy to use
Me and my 2cents
lol.
Scorpo builds a car thats does well in his chosen event and gets a few records along the way. He posts a dyno and everyones doing high level physics to prove its not a real dyno number.
As if he gives a shit or anyone that races actually cares about a dyno number.
Best build Ive seen in a while good stuff Scorpo.
Scorpo builds a car thats does well in his chosen event and gets a few records along the way. He posts a dyno and everyones doing high level physics to prove its not a real dyno number.
As if he gives a shit or anyone that races actually cares about a dyno number.
Best build Ive seen in a while good stuff Scorpo.
I agree very much that, scorpios car is quick as hell, there is many things that i liked about that build
Like that secondary hfpf stuffed in to ac bracket. Never even came to my mind but for sure best place to the pump to be.
Out of the box thinking.
There at least here in Finland is common to see on tuners that inflated numbers sell.
Dyno to dyno variance play some role but tuner must be very aware of that they inflate those numbers
and it seems that tuner who inflate biggest number sells most.... until he got reputation to be inflator.
And yes, dyno is only a tool to adjust a engine.
After to got that inflator reputation, he tune only rally cars here
because there is the most dumb customers around.
Rally car owners swallow what ever unrealistic you dare to throw to them, seems that car owners does not have any
Clue about limitations of ice engines and what can be archieved with ice technic
Those other stupidities lies many time here on 2k and 5k 8 valve 1600cc pushrod engines, they too come out from some dynos here with way over 210nm ratings in a 1500cc engines, huhhuh
On a chassis dyno, most ofen inflation is coming troug power train losses what they assume to be in even manual transmission and straight cut teeth in a level of some 30% and in a reality they are under 10.
I have seen numerous toyota 2age 1600 class engine rally car dynos with torque ratings over 250nm on 93oct fuel,
Do i buy it, no.. not even close, i buy values to some 175nm and accept tolerances up to 185nm but new normal is that under 225nm is lazy one.
That again is interesting to compare against those 2.4l F1 engines what archieved bmep ratings to 15.8 at the best with open exhausts, special blend fuels, very exotic materials, possibilities to do what ever bore to stroke ratios and so on, list is long.
That 250nm(don't even think it's the top) throw those backyard tuners 2age's to bmep close to 20 so they must archieve volumetric effiency close to 150% on atmos.
This picture shows quite well effect of vanos to have ability to keep torque curve stupidly flat over long rpm range and it shows these engines ve as well. It follow torque curve quite straight and at top ve can be in a level of 155-160% @0,5 bar boost.
That 0.5bar throws wheel torque to ratings close to 270lbft what seems to be quite average on these engines and throw crank torque values to 300-310lbft as stock what should be quite accurate.
Plot on tis shows 296 but there can be variances on boost pressure and dyno to dyno variances.
Calculated as bmep, we are again at that 13 on the best and on 11 at 6000rpm.
At the end, this is only math
To do some evaluations, my (i know there was calibration error in dyno) pull with stock head and similair
Mods than scorps have at prox 30psi.
I'm well aware that truth is somewhere in a 630whp/705 crank hp but we took it as a Finnish rally spec dyno
Plot just to show how to get inflated numbers out of a dyno.
Yes, i have there 980crank 1220nm crank dyno plot with stock head.
Like that secondary hfpf stuffed in to ac bracket. Never even came to my mind but for sure best place to the pump to be.
Out of the box thinking.
There at least here in Finland is common to see on tuners that inflated numbers sell.
Dyno to dyno variance play some role but tuner must be very aware of that they inflate those numbers
and it seems that tuner who inflate biggest number sells most.... until he got reputation to be inflator.
And yes, dyno is only a tool to adjust a engine.
After to got that inflator reputation, he tune only rally cars here
because there is the most dumb customers around.Rally car owners swallow what ever unrealistic you dare to throw to them, seems that car owners does not have any
Clue about limitations of ice engines and what can be archieved with ice technic
Those other stupidities lies many time here on 2k and 5k 8 valve 1600cc pushrod engines, they too come out from some dynos here with way over 210nm ratings in a 1500cc engines, huhhuh
On a chassis dyno, most ofen inflation is coming troug power train losses what they assume to be in even manual transmission and straight cut teeth in a level of some 30% and in a reality they are under 10.
I have seen numerous toyota 2age 1600 class engine rally car dynos with torque ratings over 250nm on 93oct fuel,
Do i buy it, no.. not even close, i buy values to some 175nm and accept tolerances up to 185nm but new normal is that under 225nm is lazy one.
That again is interesting to compare against those 2.4l F1 engines what archieved bmep ratings to 15.8 at the best with open exhausts, special blend fuels, very exotic materials, possibilities to do what ever bore to stroke ratios and so on, list is long.
That 250nm(don't even think it's the top) throw those backyard tuners 2age's to bmep close to 20 so they must archieve volumetric effiency close to 150% on atmos.
This picture shows quite well effect of vanos to have ability to keep torque curve stupidly flat over long rpm range and it shows these engines ve as well. It follow torque curve quite straight and at top ve can be in a level of 155-160% @0,5 bar boost.
That 0.5bar throws wheel torque to ratings close to 270lbft what seems to be quite average on these engines and throw crank torque values to 300-310lbft as stock what should be quite accurate.
Plot on tis shows 296 but there can be variances on boost pressure and dyno to dyno variances.
Calculated as bmep, we are again at that 13 on the best and on 11 at 6000rpm.
At the end, this is only math
To do some evaluations, my (i know there was calibration error in dyno) pull with stock head and similair
Mods than scorps have at prox 30psi.
I'm well aware that truth is somewhere in a 630whp/705 crank hp but we took it as a Finnish rally spec dyno
Plot just to show how to get inflated numbers out of a dyno.
Yes, i have there 980crank 1220nm crank dyno plot with stock head.
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Sorry but i do not see a 1000whp car there. The car is lazy and not even try to push at all. Let me show u a 3deg/10afrs/0 trims base tune on a 6870 too 4th gear pull correctly calibrated. Let see the difference. What do u think is making more power.. hmm 748ish whp just a test on a base tune. AT tranny
I could see a 5th gear calibration and ran 4th gear or some like that where if i do the same like many lately. They make 1000s. If i do that i may end up in the 1200whp.
Btw i will do 1200s. But i will show gear and calibration and logs and graph right at everyone. The only thing secret on a log is the misleading titles of the posts. Bcz u can see gear.. bcz u can see that a car is not making the power claims..
I could see a 5th gear calibration and ran 4th gear or some like that where if i do the same like many lately. They make 1000s. If i do that i may end up in the 1200whp.
Btw i will do 1200s. But i will show gear and calibration and logs and graph right at everyone. The only thing secret on a log is the misleading titles of the posts. Bcz u can see gear.. bcz u can see that a car is not making the power claims..
You can't really compare the exhaust note from an inertia dyno pull to a load based dyno like a superflow as an estimate of power. By design, the load dynos restrict the movement of the wheel where as the dynojet does not. This is why most cars require adjustment from their street tunes to run well on a dynojet, it doesn't account for the same resistances that a car on the actual road would encounter.
I agree! after being in couple other communities over the years I'v noticed that BMW guys criticize a lot more than they encourage and support!
This is what 800 hp sounds like. Only counts if your wheels slide around.
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