Jump to content
SAU Community

Recommended Posts

I agree with Chapman - in my S15 the 480cc (corrected by Maxx) injectors were running 99% duty cycle at around 185rwkw.

4 x 480cc = 1,920cc 185rwkw

6 x 270cc = 1,620cc theoreticallly = around 155rwkw.

This figure seems wrong with the corrected info from Chapman, but a couple of different places told me I was running very high duy cycle at 185rwkw.

Taking them to 250rwkw is theoretically impossible, and highly unadvisable.

My Rb20DET injectors run 92% making 176rwkw on the stock turbo pushing 9psi.

9psi is due to the better flowing RB25 head thats had a little work done to it + the head is sitting on a rb30 bottom end with big diesel lungs. :)

Rev it just that little bit more to 5500rpm, power drops and injectors hit 100% duty to try and maintain a flat 12:1 afr.

My external bosch pump is ~3yrs old now, during the holidays i'm going to wire up a dedicated feed from the battery.

Well using the injector flow formula which I learned from this forum:

270cc / 5 = 54bhp x 6 cylinders = 324bhp which equates to around ~195kw at the wheels.

In my situation the formula held up as I reached 187rwkw and needed to upgrade them.

For 250rwkw the 440cc GTR injectors would do the job and not cost the earth at $250-$300.

A malpassi regulator ( or similar) makes a huge difference. With my stock regulator the injexctors did max out at just over 200rwkw, with the malpassi regulator, they made 240rwkw at around 85-90% duty.

Also as joel mentioned, i ran a single power feed off the alternator to the pump, so there isn't so much voltage drop. This also helps.

sky30,

Its kind of on topic, with the feed from the alt/battery.

May I ask a couple of questions, to help save me some time and research?

Some may seem obvious.

1. Where did you run the wire? Along the main loom in to the car and then splits from the main loom and ran under the carpet to the boot?

2. You took the relays feed from the pumps wire wires?

3. Where did you get 30amp wire and fuse? I've looked at the local auto shops they don't carry 30amp wire and fuse assemblies.

4. Did you use 2 wires (negative & positive) or just the one?

I had my stock RB20 injectors with a Malpasi regulator running 240rwkw at about 85% duty. I have heard of cars making 260rwkw with the stock injectors maxed out with a regulator. Id say give it a go, you will be surprised.
lunaticR32:- Motor is RB30det, had a Hi-flow turbo making 240rwkw with the stock injectors at 85% duty. ECU is a microtech.

245 rwkw = ~400 bhp

At 85% duty cycle that means ~400 cc's per minute of fuel

To get a 270 cc rated injector to flow 400 cc's means an increase in fuel pressure to ~71 psi. That's almost the limit of a Bosch 044 (73.5 psi) leaving no room for boost. The best I have seen was 350 cc's and that was at 55 psi (plus 19 psi for boost = ~73.5 psi). Even then the duty cycle was a bit over 90%, which doesn't leave much for acceleration enrichment or hot day running.

Personally, I am not that keen on running a standard fuel system at 73.5 psi. The standard hoses, fittings and clamps are not realy rated for that sort of pressure. Fuel fires are very ugly. Anyonme going down that route should look at braided fuel fittings all the way from the pump to the fuel pressure regulator.

:)

sky30,

 

Its kind of on topic, with the feed from the alt/battery.

 

May I ask a couple of questions, to help save me some time and research?

Some may seem obvious.

 

1. Where did you run the wire? Along the main loom in to the car and then splits from the main loom and ran under the carpet to the boot?

 

2. You took the relays feed from the pumps wire wires?

 

3. Where did you get 30amp wire and fuse? I've looked at the local auto shops they don't carry 30amp wire and fuse assemblies.

 

4. Did you use 2 wires (negative & positive) or just the one?

I will pop in here, if it's OK;

We always have the battery in the boot (better weight distribution) so it is a short run for both earth and positive. I use the standard pump wire to switch the relay (solid state, I don't like sparking contacts around fuel). I get the relay, wire and fuses from Jaycar or Dick Smith.

:)

My external bosch pump is ~3yrs old now, during the holidays i'm going to wire up a dedicated feed from the battery.

Cubes, can u have a look at how mine is done...i want a straight feed from the battery with a relay too :) I think my 044 is using the std wiring atm....

can sum1 explain this..... i got 205rwkw on my rb20 with 15.5 boost,910 pump, 2530 turbo,dump pipes,exhaust, gtr cooler,pod and remapped ecu. AF ratio was fine. dont know duty cylce, as far as i know standard injectors. i got told many places 180rwkw is maxin out the stock injectors. but others think its ok.

if u max out injectors then u wud start to lean out... is this correct ???

there is so many different opinions with mods these days, dont know who to believe.

thats why i started the thread iam makin 220 on stock injectors and have been told they can easly make 250....then other people/tuners say no way in hell.....the obvios answer tho is if you want to make over 200rwkw its alot safer to upgrade your injectors etc

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • I don't know for sure, but I'd expect them all to be interchangeable given the diff end and hub end don't move/change between any C34 series. Often Nissan will change part numbers and the aftermarket follows those year ranges; but the original part number change doesn't mean other parts won't fit. The change could be a change in material, internal parts or even just supplier. For example, all the RB gearbox to engine bolts are no longer available and there is a new part number instead. The only change is they went from cadmium plated bolts to zinc plated due to the issues manufacturing with Cadmium. They look different but work the same.
    • One year is a bit concerning. Did you try contacting GSP? It says 5 year warranty on the box if I remember correctly. I'm also running their driveshafts on my S2 Stagea.   You could check the part numbers on Amayama for your year. Here's the link for my 1998 which gives the 39100-23U60 part number. Well, that and 39100-23U70. https://www.amayama.com/en/genuine-catalogs/epc/nissan-japan/stagea/wgnc34/6649-rb25det/trans/391 What does it say for yours?
    • I ordered a GSP Front R/H Axle from here - https://justjap.com/products/gsp-premium-front-driveshaft-r-h-nissan-r32-r33-r34-skyline-gtr-stagea-4wd#description It lasted around a year before one of the boots blew out. I'm lowered, but I have GKTech roll center adjusters. One year seems a little premature. I think I'm going to spend the extra money on an OEM cv axle this time. This website - https://tfaspeed.com/collections/nissan-stagea-wgnc34-x-four-parts/products/nissan-stagea-awc34-260rs-rb26-right-front-axle-drive-assembly Makes it sound like the readily available OEM CV axle will only fit 11.1999 Stagea and up (mine is a 2.1997 S1). The JustJap listing didn't mention any years or anything for the GSP axle. Amayama shows '11.1999' and up as well for that part number. As well as 'plastic boot type'. See attached picture. So I guess my question is, does that axle (39100-23U60) really only fit S2 Stagea? It's the front driver side. If it does, I'd love to buy that instead of rolling the dice on another GSP. I've found that OEM one cheaper here: https://www.partsfornissans.com/oem-parts/nismo-jdm-r32-r33-r34-skyline-gtr-r32-gts4-right-front-axle-3910023u60 and here https://www.nissanparts.cc/oem-parts/nismo-shaft-ft-drive-3910023u60 Just a little confused because the JapSpeed listing for the GSP front driver axle doesn't mention any specific years or anything and it fit my S1 Stagea fine. So will 39100-23U60 fit my S1 Stagea even though technically it says '11.1999' and up? What would have changed? Thanks.  
    • Thanks for the info. The only "Issue" I've had with the shifter is I always found the throw between 4th and 6th gear too close. I'm always worried to shift into 4th accidently and sending my motor to the moon. Adam LZ recently came out with a video and stated Serialnine revised their shifters to correct this and will change all the revised parts for 150$. Strangely enough, I contacted Serialnine right after and they denied it and said it's bullshit. I found that strange as he's a distributer. I'll keep this forum post updated on that saga.
    • Yep that is correct. It allows you to adjust the short throw range from what I can tell
×
×
  • Create New...