Frankiman's street/track GTR project

[frankiman]

looks like you had a bit of an issue taking them off?


i love everything. the engine bay looks so slick. ****.

one thing i am quite dissapointed at though, is that you arent doing all of the work yourself? such as the engine swap. im sure you have the know-how. i do all my own work. do you not have the time?

caused by a crazy track day

and what engine swap?
its the whole rear subframe i had swapped

and if i had a lift at home i would do absolutely everything myself

and you can't forget i took a WHOLE skyline apart, which took more than 100 hours

and spent at least another 100 hours working on both my skylines,
its not because i haven't taken the engine out for a rebuild like most other projects car that i don't do all my work,
its just that ive never had the need to take it out (woohoo)
i spent more time on brakes and suspension cause i actually do track
maintaining the car through each track day is alot more time consumming than alot of other peoples projects
;;rant;;

[archaeic_bloke]

totally understandable frankiman, so is ur motor pushing basically the stock power? or have you upped the boost? got a re-tune yet with robin?

[frankiman]

totally understandable frankiman, so is ur motor pushing basically the stock power? or have you upped the boost? got a re-tune yet with robin?

well like i said at the beginning of the last chapter, everything in that chapter was done back in july,

and the next chapter will be all about my dyno tune day with robin with graphs and stuff,
i'm pushing alot more than stock power

[Rapier46]

Oops i said engine I meant subframe..

[archaeic_bloke]

i waannnaa seee ur spec! and current engine mods

[frankiman]

rant about Big brake kits

i've heard too many weird stuff about brake from people who clearly don't anything about them

this is following the question asked about BBK in the GTR discussion section (i copied this post from the one i posted in there)


ok let's clear up some facts about big brake kits, or plain bigger brakes than original

i study mechanical engineering, so i know a bit about this
lets look at the situation from an engineering point of view (based on fact, knowledge, and calculations)


when SCC did their BBK test using a stock-ish RSX, they found that most BBK took a longer distance to stop from the same speed, why?

because they forgot what was actually touching the road

because, logically (and based on facts) a car cannot brake more than its tires alow it too
which means the maximum a car can deccelarate is based on the grip of the tires and the weight of the car (and wheels)

if you keep the same tires (lets say 300 utg street tires), and install bigger brakes, theres a certain chances you will take a longer distance to stop, why? the brakes overpower the tires

because the braking limit is still dictated by the tires threshold grip, but you are adding the rotational inertia of the larger rotors (rotational inertia grows exponentially with diameter) because they have a larger diameter AND they weigh a bit more, which has a tremendous impact on the total weight of a car


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ok now lets look at this from another point of view, the advantages of upgrading bigger brakes

i will use a personnal experience for this one,

this summer i went to a track day, a st-croix's riverside speedway near quebec city

there was a nissan 240sx, stripped out, with about 310whp, on racing slicks still using the stock single piston calipers (idiot)

this is how his pads looked at the end of the day, let me explain why
(i pickep them up after he threw them i the trash, before leaving the track)


in this case what happened is that the tires overpowered the brakes

the threshold grip of the racing slick tires was much much higher than the maximum braking capabilities of his system
which meant he had to apply an enormous amount of force the pads using the pressure area of only 1 piston,
this caused the pads and rotor to heat up quicker and to an higher temp
the temperature of the pads (porterfield brand) exceeded its designed limits which caused them to desintegrate much quicker to an extent where he did his last 8 laps without any compound left on his pads

this meant the pads metal backing was beeing pushed with tremendous force against the metal brake rotors, again everything heated up beyond the system's limits, and thats why his single piston calipers left prints on the pad's metal backing, and the rotors dug 3mm into those backing


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in his situation, it would have been extremely advantageous to use bigger brakes,
for example, lets see what would have happened with stock skyline R32 GTR brakes

1st, the bigger rotors,
by using bigger rotors, it means the calipers braking surface is further away from the center of the rotor, why is it better ? lets calculate
the stock s13 front rotors are 257mm
the stock GTR front rotors are 296mm
(296-257)/2= ~20mm, this means that the rotors are 20mm further outwards
lets assume the braking force is the same, the lever (distance from center of rotor to the outer diameter is 15% longer, which means the brake torque is 15% more

2nd, the 4 piston calipers
a single piston caliper pushes the rotor from one side against a flat part of the calip, sliding along the way loosing power
so the braking surface is actually a bit less of the piston's area, = (pi*diameter^2)/4
i think the piston diameter is about 40mm, so, pressure area is (3.1416*40^2)/4 = 1256.63mm^2
on a forged two piece 4 pistons caliper from a GTR, each piston are paired and they push the rotors against themselves, which doesn't casue loss of power like in the single piston approach
i think the pistons are 25mm in diameter each, so, pressure area, is 4*(3.1416*25^2)/4 = 1963.5mm^2
so the pressure area of the GTR calipers is 156% greater


so if you apply the same force to both systems, lets say 1MPa (MegaPascal) =145psi
pressure*area = force force*radius = torque
s13, 1*1256.63*(257/2) = 161 476.95 Nmm of brake torque
GTR, 1*1963.5*(296/2) = 290 568 Nmm of brake torque

GTR/S13
the GTR's brake system is (theoretically) 180% more powerfull than the S13's


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another advantage of using bigger brake is, that you have to apply far less force to get the same brake torque as smaller brakes, which means you are creating much less heat
and bigger rotors dissipate their heat much more easely, because of their larger contact surface with the air (inside and outside the rotor)
also, since bigger rotors have more mass, they absorb more heat (energy) so they heat up (temperature) less


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lets go back to the first topic,

like the saying goes '' you are as strong as your weakest link ''

a car's maximum braking power is dictated by its weakest link, its tires or its brake, whichever is the weakest

for most of you, using stock GTR calipers, driving on 300utg tires, you will never overpower your brakes
and if you don't go to the track, there is absolutely no reason you should need a Big Brake Kit,

to get the most performance without changing calipers,

is to go with better alloy ''plain'' (not cross-drilled, not slotted) brake rotors, like Brembo's rotors

use DOT4 or higher brake fluid, which will absorb alot more heat (energy) before boiling

use nylon/stainless steel braided brake line, that won't expand with heat like rubber lines

use higher temp brake pads, pads that have higher coefficient of friction that can still perform at higher temperatures
for example, hawk HP+ pads work from 30°F to 600°F unlike stocks that only work from -20°F to about 350°F


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about SCC's big brake kit test,

if they would have used racing slick tires like Hoosiers, tires that no street brake kit could overpower, then they would have clearly seen the difference between each brake kit


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about front / rear brake bias, not only does it influence the maximum braking performance of a car, but also its handling caracteristics under hard braking (oversteer, understeer)

thats why there are compagnies like Wilwood that make brake bias valves

brake bias is really hard to get right, since it is based on the front and rear weight distribution of a car, its front and rear mechanical grip (suspension setup), its front and rear brake system's power and its front and rear tire grip (if using different compounds or different width)
its something that can take a couple months for a group of engineers to design


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about brake pads, i will tell you something 99,99% of you don't know, how exactly do brake pads work, why do they squeal?

well, brake pads don't work based on their ''coefficient of friction'' like everybody thinks

the pads performance is based on the ''coefficient of stiction'' or ''sticking coefficient'' between the compound of the pad and the alloy of the rotor

when you brake, a layer of the pad's compound is transfered to the rotor
but only after they have attained a certain temperature (temp range of the pad)
its the stickyness between the pad and the pad's compound on the rotor that actually brakes the car

if the pads worked by friction, brake rotors wouldn't last weeks, they would erode too fast

if you really brake hard all the time, the pads will erode quickly because of all its compound beeing transfered to the rotors

so, before the pads attain that temperature, they work by friction, which makes the rotors resonate (at a certain force application) wich is the squeal you hear
over that range, and the compound with break apart, disintegrate (melt away)


thats all non-engineers should know about brakes!

[Rapier46]

interesting write up on the brakes. pretty good read.

When i brake hard in my GTR (like when im slowing down from...really fast.) Or if I'm driving hard like im on a track(there are some sweeeets roads here...). my brakes will squeek when they get hot. when they're cold, they're silent. but when the heat up hot hot, they squeel away. i may not have understand your last statement completely. could you clear this up? I've heard different types of pad meterial like ceramic will squeel more when they're hot. or have you just proved this to be false.

[frankiman]

interesting write up on the brakes. pretty good read.

When i brake hard in my GTR (like when im slowing down from...really fast.) Or if I'm driving hard like im on a track(there are some sweeeets roads here...). my brakes will squeek when they get hot. when they're cold, they're silent. but when the heat up hot hot, they squeel away. i may not have understand your last statement completely. could you clear this up? I've heard different types of pad meterial like ceramic will squeel more when they're hot. or have you just proved this to be false.

it really depends on how much pressure you apply, even if the pads are hot, if they can vibrate even just a bit, it will make the rotor resonate if the pad's vibration matches the rotor's frequency

i.e.
when i drive normally, and my brakes are warm, just just inside the operating temperature
and i brake just slightly, they will squeal, a bit more silent, a bit more squeal

pretty much all sportier pads are like that, just practice to find that spot (pressure) where it doesn't squeal, and always brake with that same pressure and it shouldn't squeal

i forgot to talk about the resonance and frequency, just though it was a bit too much engineering blahblah

and when you say ''hot hot'' its still not that hot
go on a track and repeatadly brake from 220km/h down to 60, until your brake catch fire, and smoke comes from your fenders like my car this summer, THATS HOT

[Rapier46]

slowing down from 260 to do a tight corner...thats pretty hot haha. and i havent warped them either.

[archaeic_bloke]

nice write up frank! (fellow science guy here... im a physicist)... ill agree with your arguments, very logical.

[DocShay]

wow I just read 9 pages. Worth every minute - Can't wait for the dyno chapter!

[mitch32]

I agree with you on every point but "''coefficient of stiction'' thats just pretty much coefficient of friction. The pad material on the rotor against the pad material on the pad causes a liquid to form during braking which has a high coefficient of friction which is sticky as a mofo. You can say sticking coefficient but like I said its simply coefficient of friction. The liquid may not form unless the brakes are hot enough, but for the sake of argument we can just say a liquid.

Just to enforce Franks argument, you know when you buy brakes they require something called 'bedding-in'. That 'bedding-in' is required in order to transfer some brake pad material to the rotor, without that your brakes would not work properly. If you don't 'bed-in' the brakes the material still gets transfered to the rotor it just might take longer. Also your rotors are much more brittle then your pads, thats another reason why your rotors will outlast your pads and also why braking works the way it does.

Also another cool point is that certain high-end cars with ceramic rotors actually never require you to change the rotor. The rotors are made to last the life of the car.

Keep up the good work Frank!!!

[frankiman]

mouhaaha, just got this pic from the guy who took the actual picture and had it printed in 20''x30''

this is going to look sick once i get it, and put it on my wall

[frankiman]

Chapter 6 - tuning session, dyno style


tuesday july 7th 2009

early that morning i rechecked everything again, packed extra pints of every fluids i could need and drove to Almasi Tuning, to get the car tuned my Robin Almasi

after a short 20 minutes drive, i arrived at the shop, closed

o...k, my appointment was for 10am, and its was 9;50

at 10;15, i saw an old shitbox civic park next to me (the car was named shitbox#1) crazy little racing car


a little indian guy, sajan the poonji rocket, walked out and greeted me;
''are you waiting for Robin? obviously, i'm not him'' lol

so he opened up the shop, started to get everything ready
while i was helping him, we talked alot and found out he was also an engineering student like me, but at Concordia

also i noticed this, on the dyno's screen from the day before, lets just say, its quite interesting


by the time Robin got there, the car was already jacked up, rear-wheel-less and beeing bolted to the dynapack hydraulic dynamometers





Robin placed the big ass fans in front of the car, plug all the sensors, MAP sensor, wideband AFR sensor, ambient air temp

he started asking me about engine mods;
''so, what do you got in there?''

list of engine related mods at time of tune
HKS EVC1 boost controller
HKS suction intake kit
HKS legal cat-back exhaust
Nismo 555cc injectors
Nismo FPR
Nismo fuel pump
Nismo downpipe
Nismo thermostat
Greddy FMIC
Greddy intercooler hardpipe kit
baffled twin turbo pipe
NGK-R spark plugs, gapped to 0.35''

''what about the turbos?''
stock i gues...

then he took the stock ECU out, opened it up and went upstairs to his workbench to install the chip
back 5 minutes later;
''hey did you know you already had a chip?''
maybe, tuned to jdm 150octane or whatever cause the engine was running hyper rich
reconnected the ECU to the car
then took my boost controller off and checked all the connections behind it to be able to set different boost levels for each button, since i got this crazy old HKS EVC1, with push buttons.. which is just crappy


then he plugged his laptop into the ECU, checked all the signals, started the car and let it run for a couple minutes
he got comfortably into the driver's seat, setup his work area, laptop, wireless keyboard for dyno's computer



them he checked to make sure his laptop was getting all the gauges signals from the ECU, looked at the engine temp, turned around and said ''nice, you got a nismo thermostat in there!''
just by looking at the engine temp

when everything was ready, he pressed the START button

and thats when the magic happened

garage door closed
ceiling lights turned on
fans turned on
exhaust fan system turned on
dyno cooling system turned on
dyno software booted up

i was like woahh

so typed in all the required inpurs to setup the dyno software and did a couple test pulls in 3rd gear
all his test pulls were between 3000rpm to 5000rpm,
and the lowest boost setting possible, around 8,7psi
after every pull he checked the AFR at the higher rpms to make sure i had a good enough fuel delivery system
since the dyno's cut-off was set at 5000rpm, hp only went up to ~200

then broadened the rpm range from 2500 to 6000
and then he started modifying the fuel and timing maps
with the cut-off at 6000, hp went up to ~240

and finally, full WOT pulls between 2000rpm and 7000rpm
why only 7000? cause i asked him only to tune up to there just for safety reason, i didn't want to stress the engine too much before really knowing its potential
so over 7000rpm ignition and fuel maps are pretty conservative
and to keep a good idle and low speed driveability, so are the below 2000rpm maps

i was really admiring his work, and i kept asking questions and getting his opinion on a load of tuning subjects
i had a real good time watching him work

after each pull, he said ''nice, i can advance another degree''
and he also kept ajusting fuel injection to kept the AFR as stable as possible

he maxed everything out for the final ''low boost'' pull, still beeing a bit conservative
so he got 300whp @ with peak boost of ONLY ~8,7psi

low boost (~300whp @ 6600rpm @ 8,7psi)

POWER vs AFR


POWER vs BOOST


then he got out the driver's seat, looking perplexed, told me;
''there's no way OEM turbo can move this much below 9psi, you sure you got stockers?''

to which i responded; ''i have to friging clue man''

he took a flashlight and started poking around the scalding shielded exhaust manifold, but couldn't see crap and it was obviously too hot to ''feel'' it
so he told me to wait a couple minutes as he wanted to try something

after the engine had cooled down a bit, told me to sit in the car and turn it off while he had his face right up to the exhaust manifolds,
i turned it off,
''yup thats what i though!!''
me =
then we switched places
he turned it back on, then off
''did you hear it?''
me = ''hear what?!''
again... turned it back on then off
me = ''what???''
him;''turbos man''
me; ''what about them?''
him; ''they keep spining!''
me; ''what does that mean?''
him; ''bearings man''
me; ''...''
him; ''ball bearings!''
OH SNAP...
me;

he jumped back into the driver's seat, programmed another boost setting (turned a darn screw on the back of my crappy old EVC1, i hate that thing with a passion)
my first setting beeing the lowest possible (~8,7psi)
he put the second setting at 10,5psi
then the third setting at 12psi
and did a couple other pulls

''man, you got a really healthy RB''

and this is what he got out of it

med boost (~360whp @ 6600rpm @ ~12psi)

POWER vs TORQUE


and turned around, looked at me and said;
''how high you want to go?''
me; ''dunno man, really want to keep it safe and reliable...''
him; ''*****...this setup could probly take 16psi''
me; ''ok, lets go to 14~ish''
him; ''done''

he set it to about 14psi
and did about half a dozen pulls to get it just right, making small adjustments to the ignition timing and fuel maps after each pull

i kept staring at the dyno's screen with an enormous
my original goal for that day was to leave with 340whp (exactly 400bhp)
but the hp number kept going up on the screen

final pull saw a peak power off ~381whp (450bhp) @ ~13,7psi
the 555cc injectors were at ~72% duty cycle
mafs were at ~83% capacity
oil pressure was bang on, so was oil and water temp

so it all sounds alright, even based on this calculator


high boost (~381whp @ 6600rpm @ ~13.7psi)

POWER vs TORQUE


you can clearly see torque falling off quickly after ~6500rpm, because of the conservative tune i asked him to do, cause even on the track i rarely shift beyong 7600rpm (i'm not the kind of big oaf to blow an engine at 9000rpm :P)

POWER vs BOOST


and from this chart, you can see that the turbo spool-up isn't too great, i might have something a bit bigger than N1 turbos actually

and boost isn't stable at all, maybe something to do with wastegate actuators or boost controller selenoid, my ECV1 is at least 15 years old, i might be pushing it a bit, anyway, just ordered a new one :wink:

POWER vs AFR


and from this chart you can see my fuel pump / injectors delivers throughout the rpm range without falling off

---------------------------------

so thats that, i left the shop with a bg ass smile on my face, and i got the ''good guy'' discount too,
and now all the guys from almasi/synoptic are good friends

after the tune, i went to the track with sajan a couple times, even gave me a ride in his civic
stock seats / seatbelt = never again
anyways, that car is now totalled (backed into a wall at 100+kph at calabogie racetrack :sad: )


with what i got planned for next summer, 425whp/500bhp will be an easily achieveable target
and no teasers, everything will be explained after my last 2009 recap chapter, in the projected 2010 build chapter
(btw, car as been in storage since october 20th)

[archaeic_bloke]

... wow, thats pretty mean, why did u store your car already!? theres no snow yet! lol, im still driving mine!