What do I need to safely run 15psi & 300hp+?

[m_melen]

EDIT: With all your helpful input I've got a decent list going. My original post is at the bottom of this one. Here's my shopping list so far:
Z32 MAF
Deatschwerks fuel injectors, 550cc
Tomei metal head gasket, 1.2mm with 80.5mm bore
Gizzmo intake gasket
ARP head studs
Nismo engine mounts (probably)
Stronger fuel pump, mayhaps from a GTR
Trust oil filter relocation kit
Overbored cylinders, a couple of mine look a bit wavy, I'll verify once my crank is out and I can measure
Forged pistons, JE or Wiseco
New connecting rods, no decision on what kind yet
NIStune ECU chip and software for tuning
New turbo, is an RB25 powerful enough or do I need to go aftermarket?





I'm doing a rebuild on my rb20det and I want to do it right. Before I decided to do my rebuild I found it really easy to get 10 psi when not paying close attention, so I want to be able to run 15-20psi safely without busting anything. I want to get over 300 horsepower, but I haven't decided how to get there so I need some suggestions!

Here's my shopping list so far:
-Complete OEM gasket rebuild kit, do I need to buy a metal head gasket? What specs should I go for if I do get a metal head gasket?
-New pistons, maybe JE (open to suggestions), new piston rings
-New connecting rods, no idea on a brand yet
-Cylinders re-bored, they're a bit uneven
-New K&N air filter, mine's old and broken
-New fuel filter, what kind should I get?
-Replacement stock turbo, mine's limping.

So what should I consider installing to safely run 15-20psi on occasion, and at least 300hp?

[WildCard_]

bigger injectors, stocks should hold up the power band to 280HP, then you run a duty cycle to high and hot for injectors.

Personally, Id go with a different turbo, metal head gasket, ARP head studs, Nistune(or other tune method), 400-500CC injectors, upgraded inter cooler, fuel pressure regulator, new fuel pump(prefer 255LPH), check rods and pistons(could x-ray em...replace with oe if necessary), new con rod bolts.

my 2 cents, Ive only done 2 RB20 motors. Others have done more than I, and probably have more insight.

[m_melen]

new injectors it is! i've got a front mount intercooler that seems big enough to do the trick.
a couple thoughts:
-are upgraded injectors plug and play?
-if the cylinders are bored slightly bigger won't OEM pistons not be big enough?
-ARP head studs i was planning on definitely
-is tomei the best way to go for a metal head gasket or are there other good ones?

[rak123]

-are upgraded injectors plug and play?

you will need a tune for the larger injectors or your car will still have the same pulse width as the stock ones and you will run super rich.

[WildCard_]

not necessarily with new injectors. as long as resistance is the same..it will use adaptive fuel trim (LT and ST) to adjust the fuel map. I still suggest a tune, but you should be able to reset the ecu, and within a half hour have it relearn acceptable running conditions.

your injector pulse width is gonna be lookin wickedly short on the open fire though, but wont cause any damage as long as the ecu can make enough of an adjustment to get the motor running. Ive done this with a 2JZE single...dunped 500CC injectors in and fired er right up with no tune.

[Skym]

Look at ARC240's forged RB20DET build thread. He's going through a high hp forged RB20DET rebuild -

http://forums.gtrcanada.com/showthread.php?t=41990

It should give you an idea of what works bottomend wise.

For a boost up on stock bottomend -

Tomei headgasket (1.2mm thick, 80.5mm bore)
ARP headstuds
Nissan OEM repair gasket kit for RB20DET
Gizzmo reusable intake gasket
600cc injectors (can highflow stock 259cc injectors to roughly 636cc? for around $50 or less each)
255lph fuelpump (Bosch, Nismo, etc)
Z32 AFM (good for around 480hp at engine)
Retuneable ECU (Nistune, etc)

Then at cylinderhead shop -

Skim head to even up squish area's in head, pressure test to find leaking valves and reseat leaking valves. Check valvesprings and replace if necessary (worth it to replace valve springs now, if fitting cams later on)
Check valve guides for cracks and replace if necessary
Replace valveseals with new valveseals in Nissan OEM repair gasket kit for RB20DET

[love_boost]

like skym said above.

but with injectors for 300whp wouldnt 440cc be good enough?

[RyanGTS-T]

Skym - your really all about the Gizzmo gaskets now. I think this is the third post I've just read that you've mention this. :-D

[love_boost]

Skym - your really all about the Gizzmo gaskets now. I think this is the third post I've just read that you've mention this. :-D

haha
and no youtube post?

i know a friend who is pretty into this gizzmo stuff, i guess they make alot of cheaper parts.

[Skym]

Hahaha. One of the only gaskets I know of that's stronger than stock gasket.

Or could fit custom made copper gaskets which should be stronger -

http://www.headgasket.com/faq.html

As far as I know copper gasket's are used on high hp engines running Methonal, Nitro, etc. Most aftermarket headgaskets seem to have a bit of give that makes the headgasket fail before piston rings, etc do. I have seen a blown RB metal headgasket and blows cylinder seal. It blows across from cylinder to water, oil gallery's. Engine ran rough when it failed.

Yeah, stock GTR 440cc injectors would be more than enough for around 390hp (safe hp level) at engine or 325rwhp.

But from what I have learnt from friends RB engines, you sometimes look for more hp. So sometimes it's better to go over the top just incase you want more hp.

[m_melen]

Okay, so i'm sold on new injectors.
now the only question about those is is how much i want them to be putting out. gtr ones are 440cc stock? i think i'd like to go higher so that i dont have to get even bigger ones later on. i'll start asking around for 600cc injectors.

I'm also sold on the tomei metal head gasket.
Question about that though. They offer the 80.5mm bore, if I have my cylinders bored out slightly to compensate for some unevenness will the 80.5mm be big enough? I'm a bit of a noob on re-boring principles.

I'm also sold on ARP head studs, no questions there.

Not sure on the retunable ECU, I'm just curious what the differences are between those and the stock ECU, adjustment-wise.

I've heard a z32 MAF is a good idea, but why?

Sold on fuel pump, not sure how much I need it to put out. Suggestions and explanations?

And finally, what's special about the intake gasket? Is it important to have a stronger intake gasket when running the turbocharged air because of its temp?

Thanks for all your suggestions guys, this is my first rebuild where I didn't just bring an engine back to stock values. I'm excited to see how well I can do on my first real project.

[RyanGTS-T]

fuel pump/injector size equations

well you really need to figure out what size turbo your gonna run. What horsepower you want/expect to make and add a little too it.

Like for instance you want to make 300 horsepower, so make all your calculations for 350 horsepower. That way you have some room to work with.

So we use 350 hp with 15 psi of boost for your equation.

I have stolen this equation from my AEM book.

I'd rather not spend a bunch of time explaining everything it's just easier to do it for you.

(350 x .650) x 1.25 = 284.38 lbs/hour
284lbs/7.25 = 39 gallons/hour
39 gallons x 3.785 liters = 147.62 liters/hour.

So basically you will need a fuel pump capable of running 147.62 liters/hour.

Now injectors,

((350 x .650) x 1.15) / 6 = 43 lbs/hour/injector

So...

43 lbs/hour x 6 cylinders = 258 lbs/hour

Fuel pump size is more than enough to handle the injectors. So far so good!

Convert injector size to cc/min...

43.60 x 10.50 = 457 cc/min

So GTR injectors will be a little on the small size for you. I would suggest going with some 500 to 550 cc injectors and you can probably get away with just using a stock GTR fuel pump.

Stock GTR fuel pump runs at 195 lph which is more than you'll need however if you want to just upgrade to a better fuel pump altogether your best bet/deal would be a Walbro pump. I think you can get one on ebay for around $95 bucks or so and comes in 190 and 255 lph sizes.

For a budget build go with a used GTR pump


Hope this helps

[Skym]

The formula in above post is the correct way to size injectors to fuelpump.

Nismo had 555cc, 600cc listed for RB20DET and I think was a Nismo 255lph fuelpump.

Fuelpump is in LPH (Litres Per Hour) or sometimes is rated in hp and needs to match injector cc. 1cc on injectors is roughly 1 hp, so it's fairly easy to match fuelpump to injectors if you know the hp rating of fuelpump and sometimes tells you the lph. So you can get rough idea of what lph is in hp.

Stock R32GTS-T fuelpump is 135lph and works with 370cc injectors (same lph fuelpump as used on R33 with RB25DET, 370cc injectors) but supply's fuel to 259cc injectors on stock RB20DET. GTR stock fuelpump is 195lph for 440cc injectors.

Stock RB20DET cylinder bore is 78mm, so 80.5 mm bore on headgasket is bigger. 1.2 mm is stock headgasket thickness. Best to talk to machine shop and ask what they recommend for bore size, thickness after boring cylinders, skimming head, shortblock and fitting forged pistons (forged pistons can affect compression).

Nistune makes the stock ECU retuneable like an aftermarket ECU via plugging laptop up to consult plug (plug for Nissan's diagnostic computer called Consult) that's located next to fuses, under dash on drivers side. Then you can make mapping changes in realtime on laptop. Also can check ECU for error codes (faulty sensors) anytime you want too with Nistune. Chipping a stock ECU is the old way of tuning a stock ECU.

MAF limit is when intake airflow (from bigger turbo sucking more air in) makes the MAF voltage reach around 5.1mv (millivolt). It happens around 300hp with stock R32 RB20DET MAF. With Z32 MAF, it's calibrated differently, so maxes out at around 480hp. But those hp numbers are guesses at best, as some have extracted more or less hp. Sometimes a cold night or day can make MAF hit 5.1mv.

From what I understand a MAF has a hotwire that gets cooled by incoming air and MAF tries to heat hotwire up again and circuit board in MAF measures the voltage it requires to reheat hotwire and sends that voltage to ECU which has a table (software) that converts voltage to load. The load figure on table is used to select the correct load cell on fuel, ignition maps, etc. When the hotwire gets dirty (black colour instead of white colour), MAF voltage can be wrong and ECU gets the wrong voltage and wrong part of fuel or ignition map is used and engine doesn't run properly. Sometimes the circuit board inside square box on side of MAF has bad solders which causes problems.

From what I understand the Gizzmo intake gasket is thicker, stronger and doesn't leak at higher boost levels (stock paper gaskets are known to blow at higher boost levels). Also stops heat transfer from head to intakemanifold, so intake temps in intake manifold are lower thus more air can be fitted into cylinder (air expands when hot, so takes up more room vs cold air that takes up less room, so more air can fit inside cylinder) and when mixed with more fuel = a bigger bang and more hp, torque is created. It's similar to spraying heat resistant paint on intakeplenum. At least that's the theory behind it.

[RyanGTS-T]

From what I understand the Gizzmo intake gasket is thicker, stronger and doesn't leak at higher boost levels (stock paper gaskets are known to blow at higher boost levels). Also stops heat transfer from head to intakemanifold, so intake temps in intake manifold are lower thus more air can be fitted into cylinder (air expands when hot, so takes up more room vs cold air that takes up less room, so more air can fit inside cylinder) and when mixed with more fuel = a bigger bang and more hp, torque is created. It's similar to spraying heat resistant paint on intakeplenum. At least that's the theory behind it.

How much are these Gizzmo gaskets??

I didn't see a price

[Skym]

Suggested retail price is here (scroll to bottom) -

http://gizzmousa.com/thermal-gasket.html