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Rb20Det + Upgrades Do I Need Injectors?


rx-line
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Hey all,

Wondering If I need to upgrade my injectors, Not sure what duty cycle they are running at now but I would not like to upset anything. Cockchompers at mines haven't answered my emails in months, let alone the info coming from them would be all that great. It's not in my budget right now for new ones so I'de like to pick your brains for a bit.

If I have an increase in fuel pressure I should be able to compensate for the added boost/flow.If yes what is a good fuel pressure to be running and where should the FPR be set with vaccum on/off?

Or do I need new injectors at this point? If so, I take it I need an EMS or piggy back to tune accordingly?


Rb20det parts list:
Mines ECU tuned for stock?
Pod filter
RB25DET turbo with 10psi actuator
Full 3" exhaust
Screamer downpipe
Aftermarket FMIC with 2.5" piping
Custom front facing intake plenum (more volume than stock)
Sard fuel pressure regulator.
Walbro 255 Fuel pump

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The Walbro will at least keep the pressure from falling away at the top end (like the stocker would otherwise allow) which will buy you a little headroom. But realistically, if you run an RB25 turbo to about 13 psi on an RB20 you will max out the AFM and you will go pretty much to max on the injectors too. Thereby reaching the limit.

A Mines ECU is suitable ONLY for throwing from the nearest cliff into the deepest water you can find. Just get the RB20 ECU Nistuned and enjoy life. Failing that, any modern aftermarket ECU will be more than adequate.

Don't f**k about with front facing plenums. They are a shit idea. The standard one will do the job unless you simply cannot fit it under the bonnet or you cannot make the cooler piping work. There are no other performance oriented benefits to be obtained from an FFP until MUCH higher power levels (like >400rwkW).

Don't bother with an FPR. Don't need it. If you are planning on using it to stretch the capacity of your injectors, then fine, but you won't get much more out of the stockers anyway, so probably still not worth it.

Screamer on OEM turbo is full of AIDS. Just use a decent bellmouth or well made split dump that merges back in down at floorpan level.

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I'd suggest throwing it on a chassis dyno and log you afr's just for piece of mind.

1. you won't get an answer out of MINES in Japan.

2. If you need too (probably won't) to add a little fuel then an fpr might get you there. I don't think you will need to though. Vac line MUST BE CONNECTED!!!! Set at 47psi at idle with the line attached.

3. Honestly, if you need more fuel that a tweak of the fpr will give you then I would just turn the boost down. You might.... might be able to get away with an safc if small corrections are needed

4. Only bother with a bell mouth dump if you plan to upgrade to a bolt on turbo upgrade later.

Or if you want the extra handful of kw's, then upgrade to a nistune board, Z32 AFM, GTR/ (whichever) injectors and go for broke.

The mines ECU essentially just throw a heap of fuel, moderate timing at each cell. Also removes speed cut and ups the rev limit/air flow 'boost' cut.

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Hmmm, thanks for the quite responses guys, Exhaust isn't built yet as it's a freshly swapped and running FB rx7. Going with full 3" inch and bell mouth , in case I want to slap a holset in later (why is it a bad idea to do an atmospheric gate pipe?). I know the intake actually reduces engine temp it must being so close to the engine? Mine is custom and uses only the upper half and was free so can't complain.

I have heard that mines ECU's are junk but this thing does scream much more than others I have heard... as long as it's not running lean?

the 10psi actuator will creep with added flow mods?

Can I use my mines tuned ECU with nistune?, $600 for nistune, 300- 400$ injectors and a wideband seems like quite the step up lol. Especially after buying a full adjustable suspension setup. Probably won't be doing that for some time.

Seems there are so many myths surrounding the rb20det lol.

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Hmmm, thanks for the quite responses guys, Exhaust isn't built yet as it's a freshly swapped and running FB rx7. Going with full 3" inch and bell mouth , in case I want to slap a holset in later (why is it a bad idea to do an atmospheric gate pipe?). I know the intake actually reduces engine temp it must being so close to the engine? Mine is custom and uses only the upper half and was free so can't complain.

I have heard that mines ECU's are junk but this thing does scream much more than others I have heard... as long as it's not running lean?

the 10psi actuator will creep with added flow mods?

Can I use my mines tuned ECU with nistune?, $600 for nistune, 300- 400$ injectors and a wideband seems like quite the step up lol. Especially after buying a full adjustable suspension setup. Probably won't be doing that for some time.

Seems there are so many myths surrounding the rb20det lol.

Taking those things one at a time.

1)Atmo gate. The turbo outlet on a Nissan Turbo is one open chamber containing both the turbine outlet and the wastegate outlet. In order to do a screamer on these you have to have a divider on the dump that sticks into the outlet area to keep the flows apart. The problem is that they don't seal, so you always get leakage out through the screamer and it all sounds (and works) like shit. Screamers are not a solution for the OEM turbo. They have their place (race cars). They are pretty much illegal on the road in most civilised places, so that counts against them if you're worried about police attention.

Next part of that. If you have the FFP already, and it's in an RX7 so you probably need the bonnet clearance anyway, then fair enough. They don't do anything useful otherwise, including keeping the air more cold.

2) Mine's ECU is unlikely to run lean. More likely to run too much timing for the octane fuel you have access to (although that is a little less of a problem these days now that higher octane fuels are more obtainable). Let's just say that Mines ECU have caused more than their fair share of engine deaths over the years.

3) 10 psi actuator won't creep any worse than any other actuator. It will be fine.

4) The one thing I don't know for sure (on this one - there are other things I don't know!!) is whether you actually CAN use a Mines ECU to convert to Nistune. The Mine's ECUs I have seen have just been a factory ECU socketed with a burnt EPROM in there. So theoretically they are already halfway to the work needed to fit a Nistune board. What I don't know is if there are any other changes that would prevent Nistune from going ahead. There shouldn't be, but you never know.

Edited by GTSBoy
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an atmospheric gate pipe is a certain fire risk...might sound cool but its a stupid idea.

you might have to check to see how mines have modified the ECU....if the chip can be removed easily...then you might be able to change it to nistune easy enough.

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Yes I did need clearance for my hood to fit properly plus I didnt get the factory fmic, so it was a cheaper and better alternative....

Not worried about the policia, they're to dumb to figure it out here in canada Building a full stainless exhaust and building the screamer, I know it has to be divided and I can get a better seal than aftermarket along with a longer screamer tube.. But maybe I'll just do a recirc...

Nistune is a nice setup but to be able to run that shit is way too expensive at the moment. Mines will have to do for a little while.

So 47 psi for fpr with vac line?

Thanks for all the comments guys, much better than nikoclub lol.

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Yes I did need clearance for my hood to fit properly plus I didnt get the factory fmic, so it was a cheaper and better alternative....

Not worried about the policia, they're to dumb to figure it out here in canada Building a full stainless exhaust and building the screamer, I know it has to be divided and I can get a better seal than aftermarket along with a longer screamer tube.. But maybe I'll just do a recirc...

Nistune is a nice setup but to be able to run that shit is way too expensive at the moment. Mines will have to do for a little while.

So 47 psi for fpr with vac line?

Thanks for all the comments guys, much better than nikoclub lol.

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Is this Canadian 91 octane the same as US 91 octane? If so, it's not completely terrible, but it still marginal as to whether it will ping itself to death. 93 octane is the premo stuff in the US right? That's broadly equivalent to our 98RON here, making 91MON about the same as our 95, and no-one here would run an RB turbo on 95RON. Just asking for it really.

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Lol at fire risk! really? I suppose if you are retarded ;)

oh and its completely illegal...and the obvious venting of noxious gases directly under your vehicle.....but don't let those go to your brain.

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Carbon monoxide is odorless Car exhaust is not odorless. Obviously exhaust in the car is bad, but seriously the are heaps of alive people with screamers.

And no one is arguing an internal gate screamer sounds so shit and is beyond pointless.

Edited by superben
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Hmmm, thanks for the quite responses guys, Exhaust isn't built yet as it's a freshly swapped and running FB rx7. Going with full 3" inch and bell mouth , in case I want to slap a holset in later (why is it a bad idea to do an atmospheric gate pipe?). I know the intake actually reduces engine temp it must being so close to the engine? Mine is custom and uses only the upper half and was free so can't complain.

I have heard that mines ECU's are junk but this thing does scream much more than others I have heard... as long as it's not running lean?

the 10psi actuator will creep with added flow mods?

Can I use my mines tuned ECU with nistune?, $600 for nistune, 300- 400$ injectors and a wideband seems like quite the step up lol. Especially after buying a full adjustable suspension setup. Probably won't be doing that for some time.

Seems there are so many myths surrounding the rb20det lol.

if your tuner has nistune license and software as most others do, its about 200 for the nistune board which is all you really need

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