jerryd87

iTrader: (4)

ahhhh yah bro not gona see much at all with that compression. you will see more just not much more since its not much higher then stock. gear ratios work with everything since its multiplying torque, more torque at the engine means more the gears can multiply. some people go with the auto ratio simply because of traction issues. i would have to say thats hals turbo z qualifys as terrifying acceleration

PhoenixBazoli

not even with a 3.8 stroker kit?
I mean a friend told me that 370z's made 361 whp, with nothing but a good tune, bolt ons and cam timing, stock compression (I couldn't find any dyno runs though )
I'm aiming for a little bit higher than that since I'd have a bit more displacement and compression with a 3.8 stroker
775 whp daily driver on a stock displacement?
wow!!

jerryd87

iTrader: (4)

3.8L would be getting most of its power gain from increased displacement and increased rpms if you went with bigger cams, the compression gain would still only be minimal less then 1%

cant really compare to a 370Z not sure if your running de, revup, or hr but the 370 has variable exhuast cam, plus the intake is completely variable. the computer controls the lift, timing, and duration on the intake cam so theres alot more on the table with a good tune.

i think someone was running around that whp on a 350 but iirc it was like a 4.1L stroker running 8k rpms and had a ridiculous amount of money into it. personally if im dropping 20k on the engine then ill go turbo and get double the power, which is what im currently doing just waiting on engine to get back from machining.

if your looking for that type of power and want to avoid FI i would definately say put a ls2 in it.

edit:
correction the engine was apparently still a 3.5L but it was 12.0:1 compression c10 cams, ITB's, long tube headers, a racing exhuast, custom intake, light weight pulleys(which i highly discourage since theres nothing to dampen vibrations in the crank with lightweight pulleys and a aftermarket flywheel.) and a motec ecu. mayby not 20k but i would have to say theres at least 10k there mayby more considering the motec alone is like 4kish. way more if paying someone since the cams require alot of clearancing and limiting variable valve timing. the car also dint make that until like 7k rpms so definately not what you are looking for.

PhoenixBazoli

oh you mean the SG NA project?
I really loved it, those individual throttle bodies are really enchanting xD
but as far as I know 12.0:0 compression requires higher octane levels for a proper combustion eh?
I still wanna keep it a daily driver
so I'd stick to increasing displacement
beside displacement, I'm really having second thoughts about FI
your talk really makes much sense to me
but why do you guys prefer turbos on superchargers?
I mean 11.0:0 compression and a supercharger sound like a real deal

ace32x

iTrader: (10)

more power from turbo's and tons more low end torque

jerryd87

iTrader: (4)

pretty much, turbos make way more power for the same airflow. a supercharger eats up power from the crank since the crank has to turn it. turbos not so much, back pressure eats up power but not nearly as much if you size the turbo properly

PhoenixBazoli

thanks dude, that'd really help me making a good decision about my future build ^^

DaveJackson

iTrader: (5)

Haven't clicked this in a while, but it's not really about bearing clearances anymore, is it?

jerryd87

iTrader: (4)

its really derailed *shrug*

PhoenixBazoli

sorry, I posted here by accident, I thought it was a thread on another tab >.<

Skrilla

iTrader: (15)

you are a wealth of knowledge, I've built countless motors but never the VQ

Anyway I wanted to add that altitude effects turbos over superchargers, many people dont know that and/or deny it, but again it actually becomes an equalizer so the loss also isn't a deciding factor

konrad

iTrader: (15)

bumping this thread with some questions for my own build

I have been going crazy trying to get proper clearances for my rod bearings
Factory spec is
Standard : 0.034 - 0.059 mm (0.0013 - 0.0023 in)
(actual clearance)
Limit : 0.070 mm (0.0028 in)

So as of right now I have 3 sets of rod bearings ACL extra clearance , Cosworth STD, Cosworth .025 which they advertise as .001 less factory oil clearance.

here is what I am getting:
ACL extra clearance .0045" clearance
Cosworth STD .0035" clearance
Cosworth .025 = .0017

so then I mixed halfs

Cosworth .025 + cosworth STD = .0024
cosworth .025 + ACL extra clearance = .0029

Now here is my question:
Which combination to use with what oil?

Forgot to add, Main clearances are:
.0030-.0035 with extra clearance and .0020-.0025 with std
Also I can mix halfs

jerryd87

iTrader: (4)

go with .0035 clearance thats what all mine are and have had 0 issues. couple scares with noises but none of them came from the bearings. for oil i actually ran orielys 30 weight(straight 30 dino oil no synthetic mixs.) oil with a bottle of comp cams break in additive. did first oil change at 36 miles(shoulda did it at 20.) and replaced it with rotella 15w40 because they where out of race mix's almost at 200 miles right now. for break in i did the hard break in, each gear 50% throttle up the revs and stepping it up to 75% throttle before going to the next gear(about 5 runs each gear.) but this is the first engine ive tried it on.(the break in not the oils). oil pressure on both oils was 120 at idle cold, drops to about 60 around 110ish oil temp and about 35 at 140 which is as low as it goes, all at idle. you really cant go wrong with a slightly loose engine(minus piston to wall clearance of course but even there yah have a tiny bit of wiggle room) just gotta make sure its warmed up properly before driving it.

konrad

iTrader: (15)

thanx but it seams as the .0035 is super high clearance, It gets cold here I was thinking of staying somewhere around .0025 or .0030 clearance on rods and .0020 or .0025 mains. with 10w40 if I go with the higher numbers
that would put me a little over what the factory limit is, reason for this is that my valve lash is within spec, and dont want to run into problems on the cams with too thick oil and not enough clearance

jerryd87

iTrader: (4)

*shrug* it stays a pretty constant temp here but ive never trusted a tigher clearance although yours arnt that tight even there. i would run no thicker then 10w40 though, even if i where in a cold climate i would have no intention of running my z in the cold(why we are looking to sell the wifes focus and buy 2 cars when we move.) .0035 does seem really loose until you start hearing about chevy big blocks running .007 with straight 50 or straight 60 weight oil, and there rod journals arnt much bigger then ours 2.2 inchs vs our 2.165(bigger diameter means more clearance.) Dont ask me why nissan went with such a absurd size though, 1.85 has no issues staying together at 9k rpms and over 1000 ft lbs of torque(pro stock engines). the vq should have had a 2 inch journal diameter tops, and probably would have cut back on some of the spun bearing issues, also i ran .0035 in my small block chevys in ohio (some where truck engines) and they had no issues running 15w40(small block chevy has smaller diameters so needs smaller clearances.)

you shouldnt have a problem though, i just personally dont want to run the risk of anything going wrong with the bearings based on how many people have had issues. but i dont know what clearances those engines where running and probably no one ever will.(i suspect most of the spun bearings on here are from too tight of clearances but thats me.)

bjmax

I think your right about that and the high oil temp the vq is producing is also a killing factor.

248 F to 266 F is to high. what you wanned to see in normal conditions is 200 - 215...

jerryd87

iTrader: (4)

honestly idling i wont see above 145 oil temp(wont even open the t stat to the oil cooler) and 182 coolant temp. driving around base i see no higher then 180 oil temp(right where the oil t stat opens) and 200 coolant temp. highway is in between, oil temp will peak 180 and immediately drop to about 165-170, coolant around 190

im running mishimoto radiator and thermostat(same temp as nismo) with plunger cut out of the face, heater core delete, 25 row oil cooler with mocal plate, stock fans, and for coolant im running about a quart of coolant for lubrication and corrosion resistance, a single bottle of water wetter, and then the rest water

bjmax

Thats low... where dit you put the oil cooler? and what bumper.. is there a electric fan?

jerryd87

iTrader: (4)

oil cooler is on the passenger side just off the side of the intercooler for the BP kit. no electric fan, and stock 03 front bumper but 99% of the time the thermostat on the mocal isnt even open. it takes a good 15 mins of driving in stop and go at about 85 to get it to 180 and i dont have a vented hood dropping temps either although i will soon, damn intake gets pretty damn warm

my coolant selection probably has alot to do with it, water transfers heat much better then coolant, and the water wetter lowers the surface tension and further helps it transfer heat. with the quart of coolant and the 15 psi radiator cap my coolant shouldnt boil until about 265 ish(pure water about 250) and it dosnt really go below 65 here and thats in the winter with it raining.

konrad

iTrader: (15)

I'm going to run the .0029 on rods and .0025-.0030 mains, should be a good compromise between.