To NEO or not to NEO

[DSMs_Suck]

Ok... Well here is the deal everyone. I just parted out my 93 Talon (See forum name =]) to go with a 95-98 240sx. To bad I'm in Milwaukee and had to fly out to GA to pick her up...

SO... I NOW have a 95 240sx SE 5-speed. I am planning on an RB swap and here are the details:

I will most likely go with a mount kit, with the custom driveshaft and just buy the motorset as opposed to the front clip.

In conjuction with the standard RB swap it will go together with:- Metal headgasket, most likely power... possibly cometic if they make one.- ARP Head Studs- Full Stainless Steel 3" Exhuast- 4" Intake with Blitz Filter- PTE (Garret) NICE FMIC (3.5" Thick).. Supports well over 700 horse. All the intercooler piping and prolly a Tial BOV.- PT-63 Turbo: 63mm 56-Trim Compressor in a T04S cover, and not sure on exhuast wheel... I think its around p-trim in a .63 A/R T3 Turbine Housing. Big Shaft CHRA. Rated at like a max 700-750 Horse.- Some Clutch... Undecided, may go with RPS or ACT Extreme. A 300zx NA turbo correct?- Walbro 255HP, Blitz Injectors (Not sure yet if 550 or 850)- Either Z32 Air Flow Meter + AFC, or more likely something custom like a blow through Hot-Wire (maybe GM?!) with a controller I make.

Now the question I have is... Will the standard RB25DET hold.. I've opened up SR20s before and WOW, if they make their sixes anything like the fours it will be fine. I plan on eventually running like 25 - 30 psi (granted with race gas) with my turbo and it should make around 600ish horse, maybe 500-550 at the wheels.Daily driving I'll keep it down to probably 15-18 on pump gas and would assume it would be about 400ish to the wheels.

Otherwise I would definately consider the Neo6 motor. Has anyone actually verified that the internals are stronger on a Neo6? Also this thing about the injectors being top feed... Hell that almost sounds GOOD to me, in general top feeds are cheaper, especially If I could get the Mitsu style top feeds to work... then I would just run good and cheap delphi injectors. What else is different about that motor? Honestly the price isnt too much different, I think if the internals are stronger that is justification enough.

As far as the VVL or VVT... whatever it is... I'm assuming it operates a lot like VTEC and would literally work with either a VAFC or with a simple switched 0 or 5 volt signal correct? Hell that would take me no time to create a variable RPM based "window switch"

I guess at this point I am almost leaning twoards Neo 6, simply because for the little extra in price I get, stronger internals (if verified), better VE in the motor, a newer motor, possibly better injector pricing?!

Anything I am over looking here when making this decision (regular vs. neo)? ... Anything missing with the setup?

I have just got into this stuff and I know a lot of you have been in it for sometime now, so I am definately open to what you guys are thinking,

Murray <- Now a 240 owner

BTW, I apologize in advance for any abreviations or DSM lingo I have put in this post... That damn crap is embedded into my brain like the plague after like 5 years of dealing with them.... Don't worry it will be gone soon enough. I am glad to be part of the Nissan community

[Wulfgang]

Dare I ask.... With all of that money, why not start with an RB26?

[xjon]

check out "fito" for his set-up regarding the rb25det. The only one that I know that has taken it to the limit of stock internals.

Need more people to verify the potential of the internals so it's just not a fluke thing but its a good place to start.

Oh yeah, why bother with a 4" intake when you place a restrictive (compared to 4") z32 maf on it?

[rbsileighty]

Dare I ask.... With all of that money, why not start with an RB26?

I second this... unless you are dead set on a 25.

People tell me all the time, "Why don't you go with a 25? For the amount money you're putting in a 20, you'll have one strong 25." I like 20's, and I want to build one... that's why.

[Nameless EJ6]

I think you should stick with a non neo motor.

And I think you should forget about the VVT thing. It's not quite like VTEC.

[93RPS13]

i third that too, also with all that power you need engine management, which i dont see...

[DSMs_Suck]

Well if I run the z32 I would need to have a 3" Intake to 4" adapter at the turbo.

However I honestly want to run a blow-through MAF such as a GM 3" or something then convert the signal to something the RB ECU can interpret.

Honestly I give the Nissan ECU a lot of credit... I believe that with a MAF that doesnt overrun and gives a clean signal to the ECU should do just fine leaving the stock ECU to run everything... My only real concern at that point is ensuring that ignition timing gets retarded a bit and the knock sensing system is working properly. I have seen turbo KAs, tons of DSMs, Supras, etc.. All easily double the stock horsepower output with simply the addition of injectors, an AFC type controller and a good air flow metering system. And I'm sure the Nissan JDM ecu can hang with the best of them..

So how does the VVT thing work... What exactly is it?

Well the 26 is straight out about twice as much... Plus it wouldn't make that kind of power unless I did some work to the 26. The turbo still isnt enough, and it would still need an injector upgrade and everything... Only thing is that it undoubtably will hold the power... I was just hoping that one of the RB25 motors would do it since they are alot cheaper.... trust me I am still a college kid here, I just have a decent amount of money left from when I parted out the DSM.

BTW, thanks for the responses thus far guys,

Murray

[rbsileighty]

You definitely did use to have a DSM. We typically don't mess with the GM MAF/interpret setup, but use a Q45 (90mm) or MAP setup instead.

Remember that by the time you buy the timing, fuel, and boost piggybacks... you have almost paid for a standalone (Microtech/Apex).

When dealing with the 26 vs. the 25, and the amount of upgrades you have planned... I would look at final cost instead of initial. If you were shooting for 400rwhp instead, then you might come out spending less with the 25.

[GTR Shop]

The NEOs are a PITA!Replacement bigger injectors are the worst things to source.. and NOT cheap either.

The VVT is simple.In the side of the head at left front (looking into a engine bay) is a hexagon 'bar' poking out with a electrical connector on the end of it. the 'bar' is approx 1" diameter and 2-3" long.At ~4500rpm the solenoid in it is energised, opening oil passage up that flows through the head, up into the front cam journal and pressurizes the internals of the inlet cam gear arrangment.The pressure give the cam gear a tweak in relation to the camshaft. I can't remeber the severity but 15degres sounds familiar from memory.

Thisis good as you can run agressive inlet cam timing down low and then have the advantage of the 15deg change up top.The system creates a brief moment in which the engine feels quite flat during change over.. then takes off.It can ALMOST be tuned out with fuel and timing.. ALMOST.

Alot of tuners pull the solenoid out and fix the oil path in the 'high' setting with a custom shuttle.

If required I can take pics of the oil passage etc if required. I always have stripped RB25 head lying around.

[93RPS13]

remember that by the time you buy the timing, fuel, and boost piggybacks... you have almost paid for a standalone (Microtech/Apex).

exactly, you spend all that money for a GTR motor why not spend another 1500 or something and go standalone, you can tuning you car for racing gas pump gas etc with a wideband O2 sensor of course which is another couple hundred but you can aways do that later... and also you goin to need a whole lot of traction LSD, and the most important of all you goin to have to get a aftermarket radiator and pushers and that not on your list, with all the power and the stock radiator its goin to kill your $6000+ car investment

[DSMs_Suck]

Hey thanks a bunch for the info! VVT sounds simple enough and yea sounds like it could be controlled with a window type switch if one wanted to...

Also thanks a bunch for the info about the injectors. I was hoping that the injectors would be a standard top feed kind, like what are used in honda, mitsu, toyo, etc.

Sounds like I will stick with the regular old RB25DET. I saw fito's setup, definately bad ***! Thats almost exactly what I am shooting for.

Again guys thanks for all the response and I will keep you updated on the status of my car. Nothing will really be happening until the school year is over, cause my classes keep me busy enough as is.

[DSMs_Suck]

I plan on using a wideband setup from tech edge, to tune the car...

K, I will probably try to run some electronic pullers with the stock radiator at first...

Murray

[Yellow4g63]

Welcome Fallen DSM brother lol:D Hey check out the Socal DSM list. A dsm guy named Ziggy just relased his Wideband O2 setup. I just picked it up with the monitor and software. It will display EGT,Boost,Lamda and A/F. It has the Data logging software with it too. http://www.zeitronix.com

[dekand]

i just dont see how you can want to spend money and get high hp, and skimp on the radiator... lol but then again (and im not insulting you) my brother was a DSM guy, and thats typical stuff...

im only going for 300rwhp with my 25 and an aftermarket radiator is on my list...

dont skimp

[GTR Shop]

YOu guys looking at wideband setups.. go no further than the LM-1 from Innovate Motorsports. Professional quality with a DIY Price and the best piece of datalogging software I've ever seen!

[DSMs_Suck]

I will do the radiator if needed. You have to understand this setup will cost a fair amount but for example all of the piping is owed to me (read free) or The turbo I picked up for a good deal from a DSM guy that realized it wasnt the street turbo he wanted. GM sensors are like $35 from a junkyard and work amazingly well, its just a matter of getting the signal transfered.

I just have trouble trusting a motor that is given to me from someone I don't know... hence the basics like the headgasket and studs, especially since those are the known weak points.

I will definately consider the radiator I just want to run it with the fans and see what happens. If its needed I will have to fork over. Honestly to get my car running at first I want to just do what is needed.. I agree the DSM way..

BTW Innovate does make a really nice setup. I will probably run that if I dont want to go through the hasstle of assembling the one from tech edge.

Murray

[GTR Shop]

We run R32 GTR radiators in S13s with twin AC fans on the front.THey don't even think about getting hot!

Run a AFM for as long as possible.. RB25 will make over 200kw ATW, or a Z32 or Q45. They measure air alot better than a MAP setup which has no compensation for airtemp.

If you do you a AFM, don't just put a Q45 one on beacause its the biggest... if you're maxing a RB25 one, then go the next step.. you want as much resolution as the motor uses.. no point on useing a Q45 AFM to only get it maxing at 2.5v.. better off to run a RB25 afm at 4.5v as you are using about 90% of the scale as opposed to 50% on the Q45.I've seen people trying to tune Starlets with BIG afm on them and wondering why they can't get the motor to run smooth.. they are tryig to tune the motors whole airfloe range over less than 30% of the AFM resolution!

[fito]

Hi, I use the NEO engine on my car. In my opinion, after you modify them (NEO Vs. OLD RB25) they are just the same. The big plus I saw from the NEO it's that you know it's a newer engine ( 1998 +). The engine has produced 587HP with all it's internals stock, the parts that started giving away were the head gasket and studs. I damaged a piston ring, but that was my foult! With your future plans, you should go with a stand alone. Forget the air flow meter, forget the wiring, forget about what type of injectors, and over all of that it's allready tuneable. Also you'll need more fuel, RB25s are thristy little suckers. On the radiator thing, I have the stock one with two flexlite fans and it works fine.

[rbsileighty]

We run R32 GTR radiators in S13s with twin AC fans on the front.THey don't even think about getting hot!

Run a AFM for as long as possible.. RB25 will make over 200kw ATW, or a Z32 or Q45. They measure air alot better than a MAP setup which has no compensation for airtemp.

If you do you a AFM, don't just put a Q45 one on beacause its the biggest... if you're maxing a RB25 one, then go the next step.. you want as much resolution as the motor uses.. no point on useing a Q45 AFM to only get it maxing at 2.5v.. better off to run a RB25 afm at 4.5v as you are using about 90% of the scale as opposed to 50% on the Q45.I've seen people trying to tune Starlets with BIG afm on them and wondering why they can't get the motor to run smooth.. they are tryig to tune the motors whole airfloe range over less than 30% of the AFM resolution!

I am glad you brought this up... I had said this point a while ago and had been shot down by the forum. Since I had no exp with the Q45 maf, I assumed they were right (not a good thing to do). The Q uses a 2 bar vs a 3 bar maf right? I guess you could always try to transfer the guts from the 25's to the Q, but again I don't know if that would work.

Here is that thread:http://www.nissaninfiniticlub....t=q45

[GTR Shop]

There is no pressure rating to a AFM what so ever.It measures air moving through it. (Mass Air Flow- MAF)

You are tugging yourself if you go to a big AFM without getting 90% though the std one 1st.AFM is a restriction??? what about the tiny minor on your turbo and the piping leading to it??

Rule of thumb, is to go up to the NEXT size from what you have WHEN yo have to..

[rbsileighty]

I would say that makes since. Good point...

After reading through your post again (the one I quoted), I see what you were saying. I have never really understood the MAF's. I see you say the MAPs can't tell air temp... I thought MAPs have a temp sensor? This part of the system is kind of grey to me... it would be nice to clear it up.

[GTR Shop]

A MAP sensor is just a pressure sensor.... thats it.

Depending on the ECU as to whether it runs temp sensor and also what temp compensation maps in the ECU are capable of.

BTW.. whos turned my bloody signature off?????

[jbanach77]

when you upgrade your fuel system don't forget to replace the lines. the stock lines are going to hold back alot of flow. the last thing you want to do is get all the right parts for your fuel set up and then burn up a piston cause you overlooked the lines.

[GTR Shop]

The factory lines have no problem with fuel flow.Infact once you add a big fuel pump, the factory FPR can't bypass the increase in flow and fuel pressure rises. Bosch 044 bumped the fuel pressure ~12psi on a std RB25 reg in a S13.

[jbanach77]

well i guess the 240's aren't like th 200sx se-r's. once over 350whp the fuel line size diameter needs to be increased or the volume of fuel delivered is not enough to maintain a reliable amount of horse over 350+whp

[Wulfgang]

GTR Shop, your sig still works. It only shows up in your first post in any thread (someone pointed this out to me just last week).

rbsileighty, there is a good description of MAF vs. MAP at the sds-efi website, although they are heavily biased towards MAP (which is unjustified in my opinion).

But basically, the MAF directly measures the mass of air flowing into your engine (for example, in lbs/min). It needs no temperature correction because it directly measures mass flow. This number is then directly related to a fuel mass flow (or injector pulsewidth) by your ECU.

MAP measures manifold pressure, which can then be used along with temperature and an estimate of volumetric efficiency to calculate the mass air flow. The ECU must first convert the MAP reading, the temperature reading, and the volumetric efficiency to a mass reading before using to calculate injector pulsewidth.

Obviously, the MAF has the advantage because it requires no volumetric efficiency estimate and is a direct measure. However, in practice, your ECU has fudge factors in the fuel maps anyway, so tuning is always required, even when you have a 100% accurate mass air flow measurement from your MAF.

Anyway, I disagree with sds-efi that MAP is "better" and the wave of the future. They only say that because some people have this perception that MAFs are sooooo restrictive, when in fact they aren't. (Well, maybe the fact that they only sell MAP systems has something to do with it )

[rbsileighty]

Yeah, I thought I had seen temp sensors in the MAP setups I had looked at before.

I figure only replace things that become a "throttle" to your system. It would be nice to have had exp with both systems because I don't usually like making strong opinions on things I don't have exp using.

When I bought my motor it didn't have a MAF at all, so I just picked up a RB25 unit for my 20.

[Wulfgang]

So are the RB25 and RB20 MAF's the same, or are you running some aftermarket engine control?

[rbsileighty]

I might pick up a 5 knob S-AFC for my 550cc's and MAF, as long as the old school afc will do the trick. This is holding me over until I pick up my Microtech this time next year (suspension comes first). The Z32 and the 25's MAFs are similar (same size).