Predicting Performance Outcomes

[Phoenix]

I have been wondering what some of the EOM limits would be for a mild increase in boost levels. This information contained below is a collection of data from manufacturer and after-market tuners (thank you mindlessoath, Jeremy Blackwell, etc.).

This was from an Endless Inc. post
520 HP 62 kgm (@ 0.75 bar)
*** other tuners have come up with similar evaluations at varying levels of boost using OEM equipment and tuning the ECU to higher boost levels.

So I did some math based on the following assumptions:
Nissan Factory Data:
a) 433 lb-ft torque
b) 0.7 bar max factory set boost
c) sea level
d) linear relationships between TQ / HP / boost as you travel nominally up the curve from 0.7 - 1 bar (10.2 - 14.5 psi) of boost

Boost TQ
(bar / psi) lb - ft
0.7 / 10.2 433
0.9 / 13 551
1 / 14.5 618.6

And the relationship between kgm, horsepower, and boost
520 HP / 62 kgm / 0.75 psi

So this is probably more inline with the under-reporting that dyno numbers are showing versus preliminary manufacturers data.

Another table for the above, it suggests:
HP Kgm
520 62 (@ 0.75 bar)
670 80
712.9 85
754.8 90 (factory specified limit)

The factory has boost cut at 1 bar / 14.5 psi. The clutch appears to run into a ceiling (according to Endless) around this point which equates to approximately 618.6 lb/ft of torque and 712.9 HP using math and not real world testing. The IHIs are likely approaching less efficiency as you approach this point of the power band anyways, so the actual dyno numbers may be starting to come down off the top of the curve.

For me, this is good news. It seems that we can safely approach 0.9 bar (13 psi) using the OEM equipment without any slipping or insidious damage to the transmission or mechanicals. Any other thoughts or considerations (plasma coating, etc.)?

For me, anything more than 600 lb/ft of TQ gets ridiculous for most applications anyways.

[mindlessoath]

well, i think the plasma liner will be fine at that power, but it may degrade faster over time if used heavily at those levels for racing.
we dont officialy know how long the liner lasts for. there is not even any real world testing sofar other than the GT-R. so its not really easy to tell.

all i can say is that the tranny and oils must be freking cooled down using the external radiators/intercoolers. this is going to be a must!

i belive harison has one of these but im not sure if its for sale, or if its even enough.

plus will any of these internals have to be hardened for better reliablility at those temps and speeds etc? it would be nice to also change the gearing a bit at those horse power levels.

i was wondering about compression ratio, anyone have some ideas on this? im pritty sure they are not going to change?

it was also noted from 7tune.com (when they translated best car or holiday auto magazine) that the engine could easliy handle 600+ hp but that they had to tune it down because of many factors, mainly they didnt even need to run that high with the rest of the technology, all that hp basically wouldnt make the car balanced anymore - it wouldnt be as good on the track with that much horsepower (im assuming its because of the gearing).

really what im hitting at here is gearing is the main problem here. even so, more horse power with mild tweeks as simple as boost is welcome!

i freking love the what you have done by the way. can you share your maths

[Phoenix]

Originally Posted by mindlessoath

well, i think the plasma liner will be fine at that power, but it may degrade faster over time if used heavily at those levels for racing.
we dont officialy know how long the liner lasts for. there is not even any real world testing sofar other than the GT-R. so its not really easy to tell.

all i can say is that the tranny and oils must be freking cooled down using the external radiators/intercoolers. this is going to be a must!

i belive harison has one of these but im not sure if its for sale, or if its even enough.

plus will any of these internals have to be hardened for better reliablility at those temps and speeds etc? it would be nice to also change the gearing a bit at those horse power levels.

i was wondering about compression ratio, anyone have some ideas on this? im pritty sure they are not going to change?

it was also noted from 7tune.com (when they translated best car or holiday auto magazine) that the engine could easliy handle 600+ hp but that they had to tune it down because of many factors, mainly they didnt even need to run that high with the rest of the technology, all that hp basically wouldnt make the car balanced anymore - it wouldnt be as good on the track with that much horsepower (im assuming its because of the gearing).

really what im hitting at here is gearing is the main problem here. even so, more horse power with mild tweeks as simple as boost is welcome!

i freking love the what you have done by the way. can you share your maths

RE: plasma liner
it is my understanding that the plasma liner has been extensively tested and should pose no problem with most applications; it hasn't been over-engineered necessarily, but it certainly seems to have been designed to operate up to 600 HP using OEM equipment under racetrack conditions.

The following article published by:
Plasma Spraying of Lightweight Engine Blocks
G. Barbezat
Sulzer Metco AG (Switzerland), Wohlen, Switzerland
K.Harrison
Sulzer Metco (UK) Ltd, Risca, Gwent

Coating Performances in Engines-
Systematic friction measurement studies in gasoline and diesel test engines have shown that the plasma sprayed coating can contribute significantly to the reduction of the friction between the piston group and the cylinder liner in comparison to cast iron. Depending of the choice of the piston ring material and of the tangential stress of the ring a 20 to 30% reduction in friction was measured in test engines. The measurements of friction were done in the Institute FEV in Aachen, Germany. The results show that a significant improvement in comparison with cast iron can be achieved.

In particular, the tangential stresses of the third ring can be significantly reduced, the critical limit is located at about 10 N. A value of 20 N can be recommended compared to the standard value of 40 N for cast iron. The geometry of the ring also plays a certain role. With optimization of the piston ring geometry, materials and tangential stresses, a potential of 30% reduction of friction in comparison with cast iron is possible.
Measurement of oil consumption has also shown that a reduction by a factor two in comparison with cast iron is possible. In this case the topography after finishing plays an important role.
The oil consumption is directly dependent on the surface topography after machining. The best results are achieved with a value of Ra 0.2 microns. If the Ra value after machining is Ra 0.6 microns or more no improvement in comparison with cast iron can be expected.
An extremely low wear rate relative to cast iron was measured in engine testing. After 150,000 km the wear on the top ring area was about only 10 microns. Also in a high loaded diesel engine the plasma sprayed coating showed a significantly lower level of wear in comparison with cast iron. In a diesel engine for automotive with a power level of 50 kw/l the measured wear on the rings and on the liner was a factor of two lower than cast iron [11] after 300 hours full power enduration test.
The results from engine testing have been confirmed in series production engines for both gasoline and diesel fuels.
- Formula1 and Formula3 for racing in 1999
- Motorcycle engine in 2000
- Large volume I5, I6 diesel for VW in 2002
Additionally several prototypes of modern gasoline and diesel engines are now involved in long term testing. The test results havw been confirmed in Europe and Japan by several engine manufacturers."

So it seems the technology has been in place for a reasonable period of time, appears to be economical, and have nominal wear rates under most conditions. According to above data, it should have ~ 10 microns of wear over 150,000 km (93,205 miles). The coating applied to the GT-R bore is 150 microns, which is the same as used in this study. That works for me.

RE: Fluid Temps
I guess we can monitor just about everything using Gran Turismo on-board. I will be following the oil, transmission, and differential change rates posted by TokyoGTR per Nissan spec. If higher boost levels are used above 0.9 - 1 bar
(13 - 14.5 psi), there would likely be higher operating temperatures and degrade. I would monitor and add cooling pieces 'as needed' to keep in specified ranges. There was a post by a tuner that if using the GT-R under high boost applications and / or race applications, to include the price of a new clutch each year in your maintenance costs. I would need more confirming evidence on this, but I am sure driving technique contributes significantly.

RE: Compression Ratio
I believe OEM is 9:1. I don't know what the limits are on this engine. My impression is that the transmission and the differential seem to be the limiting factors over the internals capacity.

RE: Math
I took a few dyno captures and real numbers from tuners that have published their boost levels versus torque and horsepower levels. It is ratio and proportion and a few conversions to get the projected numbers. For example: If you take the factory boost level of 0.7 bar and convert to psi it equals 10.2 psi; then set up a grid e.g. 10.2 psi / 433 ft/lb (TQ) as related to 13 psi / X. Therefore, (by cross-multiplication) 13 /10.2 X 433 = 551, so X = 551 ft/lb TQ. This can be expanded out for any psi level up to the efficiency of the IHI turbocharger. So as long as the formula above is on a fairly linear part of the powerband (as seen on a dyno sheet), it should be applicable. As you approach optimal efficiency, the curve will flatten out and the psi increase will not produce any gain because your engine has reached tolerance, the turbo has no> flow and grenaded on you. And this is why you see the gain of more psi on the stock turbo units not producing as much power as you get over 1 psi. I am going to stay around 0.9 bar / 13 psi or maybe 14.5 psi on track days to get the most longevity out of this beast.

Disclaimer: this is preliminary and does not necessarily equate to real world application, but you gotta start somewhere.

[mindlessoath]

1.25bar and 611.1ps with 79.8kgm

[Phoenix]

Originally Posted by mindlessoath

1.25bar and 611.1ps with 79.8kgm

OK, haha.

This is theory. I used very few data points and 3 variables. I considered atmospheric pressure a constant, if you will, because I don't have enough dyno variable sets to incorporate into an equation. [please explain how to use 1.01 in this formula...multiply or divide ) This is a RATIO / PROPORTION grid with a couple conversions. I had 2 data points with which to compare with the factory numbers. Not much to go on. When you consider that different types of dynos (dynapack / mustang & dynojet) are being used at different elevations, yeah sure, it's not perfect by any stretch of the imagination. Plus, people use different octane fuels and measure crank vs. wheel with the other confounding factor of what to use for drivetrain loss (15 - 25%). One other thing, Nissan obviously, did not provide the ideal baseline to work from, because most consumer cars are showing around 435 HP to the wheels. Even with a conservative 'drive-train' loss of 15%, your over 500 HP to the crank.

Additionally, the 'load-type' dyno (mustang / dynapack) requires accurate on-road aerodynamics and friction inputs and the 'inertia type' (dynojet) does not. I think the 'load-type' dynos are GAY, sorry, my personal opinion. I much prefer the dynojet for higher HP applications. Most tuners use the dynapack for comparing baseline (prior to modification) numbers to engine mod; it is fine for looking at change. Dyno jet will give a much closer real-world number.

In terms of the theoretical number projections, this is what I posted originally:

Boost TQ
(bar / psi) lb - ft
0.7 / 10.2 433
0.9 / 13 551
1 / 14.5 618.6

Motor Trend (K+N engineering)
Wheel 430.6 - 435.8 HP, 425.3 - 439.1 lb/ft (range of results)
Projected Crank @ 15% drivetrain loss 506.5 HP / 500.4 TQ

Motor Authority (Dynapack)
475 HP / 428 lb/ft TQ to hub
projected crank 550 HP, 495 lb/ft TQ

Autoblog (Mustang and Dynagay)
406 HP / 414 TQ (Mustang)
452 HP / 448 TQ (Dynapack)

BEST CAR Magazine (JDM [consumer])(Dynapack)
485.665 HP / 428/1 lb/ft TQ (hub)

BP car (running 95-96 US octane rating)
457.7 HP / 444 lb/ft TQ (wheel)
520.5 HP (projected crank)

JSpec Connect (Dynapack)
460 HP, 456 lb/ft (hub)

I believe there is a general consensus that the power of the engine has been under-reported for whatever reason. The numbers given by the factory are probably more accurate (with a proportion given to drivetrain loss) as being wheel horsepower rather than crank horsepower. That is why the numbers seem skewed. Give me better data points, I'll give you better projections.

Conclusions: I don't think it is unrealistic at all for the stock components to give between 550 - 600 ft/lb of TQ (to the wheels) as you approach the drivetrain limits (as given by MCR and Endless) of ~ 14 - 16 psi on the turbo. Heat and efficiency limits considered. And of course, they probably beat the piss out of the car as well.

Alright, done. sorry about the

[mindlessoath]

no problem. i just relayed the message

[Phoenix]

Originally Posted by mindlessoath

no problem. i just relayed the message

Wasn't directed at you or really anyone for that matter. Just always good to have dialogue on this topic. I have done a couple builds and it is always good to have as many perspectives as possible. That is the journey. I am trying not to be as experimental as I have been in the past.

Sorry about the confusion.

[mindlessoath]

i enjoy your post. please make more like this!

[mindlessoath]

amuse R35 has 1.25bar and 611.1ps with 79.8kgm

hopefully this will help further your equation.
08apr25_112856_img_r35-gtr.jpg (image)

[Phoenix]

Originally Posted by mindlessoath

amuse R35 has 1.25bar and 611.1ps with 79.8kgm

hopefully this will help further your equation.
08apr25_112856_img_r35-gtr.jpg (image)

1.25 bar is at the very limits of what the turbos can produce for this set-up (IMO). It is likely at the end of the curve that I produced and shows what can be expected from OEM safely. I still can't stand Dynapack. I really wish they would find a Dynojet, but it shows that the power at the crank is likely a proportion greater than what the Dynopack is detecting at the hub. Wow , that must be a FAST car. I would likely look at the intercoolers and piping for optimization, as well as consider a water / methanol injection kit to reduce intake temperature by 30 - 40 F and prevent any possible timing pull. I personally am still waiting on more data before attempting a push pushing > 1 bar, just so the transmission and diff don't implode.

The Amuse data shows 1.25bar and 611.1ps (602.7 HP) with 79.8kgm.

"Another table for the above, it suggests:
HP Kgm
520 62 (@ 0.75 bar)
670 80
712.9 85
754.8 90 (factory specified limit)"

My initial data was for 670 PS (HP) - 80 kgm at the CRANK. The dynapack is showing at the hub. Depending on the proportion gained or lost through drivetrain, it really isn't that far off. The boost settings are what needs more input; I need to look at this more. Thanks for the graph.

[Phoenix]

Amuse 79.8kg/m = 577 ft/lb at hub using Dynapack

I projected:

1 bar = 14.5 psi = 618.6 ft/lb at the crank

As you approach maximum efficiency of the turbocharger, the gain from more pressure is less, but once you convert the drivetrain loss (convert from wheel/hub to crank), it really is pretty close; assuming 15% drivetrain loss.

It isn't perfect because it is missing a bunch of variables, but it is a good place to start if you are looking at pushing to modify without grenading your engine or transmission.

[mindlessoath]

nissan also states only 10% drivetrain lose.
CBA-R35: R35 Drivetrain loss.