Sard 800cc Twin Jets

[RB20JT]

Ey,

i got a mate that suggested i put bigger injectors in my rb20. At the moment i got std injectors, with highflowed r33 turbo, front mount, fuel reg, fuel exhaust system, pod filter. Im planning to replace the std ecu with microtech in the next 3-4weeks. IS it a big difference with bigger injectors? if so....in wat way? and if 800cc are too big...hopw big should i go?

[QRI05E]

Im in the same boat but with an RB25DET.. I'm getting a highflow turbo, FMIC, Walbro pump and Haltech ECU fitted soon and was wondering wether to put a fuel pressure reg or get larger injectors.... $250 Vs $900 few tuners said the highflow turbo would max at 240 - 250 rw/kw which the stock injectors with rising rate FPR have achieved on some R33's at 90% duty...

Cheers

[RB20JT]

u need fule reg anyways dont u? i got one....so anyone? can u explain the G.O with bigger injectors thanks

[QRI05E]

With larger injectors and larger fuel pump, the standard fuel rail pressure will be fine... theres no need for an after market FPR. You only need a rising rate FPR when the injectors are closing to their max duty... 800cc's are good enough for approx 800hp... 550cc will be a better option cause they will be easier to tune...

Edited January 7, 2007 by QRI05E

[R31Nismoid]

Ye, no need for an FPR

Just get injectors to suit your application.

If its 300wkw, then you only need 550's, if its 400rwkw, then 740's etc.

Dont go bigger than you need too

[RB20JT]

uhuh... im looking for no more than 250 kw so yer....wat kind of injectors could i be looking at and wat price?

[QRI05E]

Probably GTR injectors + FPR would be your best bet... 480cc and i "think" they are direct drop in cause both the RB20 and RB26 are both top feed if im not mistaken?

Otherwise Nismo 550cc will more then enough and you wont need a rising rate FPR

Cheers

Edited January 7, 2007 by QRI05E

[RB20JT]

uhuh...alright sweet. thanks a million!!!

[RB20JT]

ok one more qUESTION....can u go too big with injectors?

[QRI05E]

Well once you tune the ECU, any size injectors can be used for example at 250rw/kw the Nismo 550cc might reach a duty cycle of 65% where the Nismo 800cc wil only reach 50%. But this also means the larger the injector the harder it is to tune therefore you should only ever get injectors to match your power goal...

250rw/kw = 550cc max otherwise would be overkill

GTR injectors are 480cc so theoretically will support 480hp (80% duty) at the fly wheel. Therefore 480hp - 30% (drive train loss) = 336rw/hp = 250.56rw/kw (80% duty)

Hope this helps

Regards,

Sarkis

[RB20JT]

uhuh!!! well thanks fopr that info..therefore 800cc OVERKILL!!!

[QRI05E]

For a max power of 250rw/kw, Yes 800cc are an overkill... Dont get me wrong, they will still work fine but wont be utilized as well as the 550cc in other words you wont be using them to their intended potential...

Cheers

[RB20JT]

ok...so if i buy say the nismo 550cc injectors would i need anything eklse to install them? like do they fit on the std fuel rail?

[QRI05E]

You will not need any other parts, as long as you order the correct ones for the RB20 they will fit straight in the stock fuel rail.

Cheers

Edited January 7, 2007 by QRI05E

[T04GTR]

yeah 550's would be ideal for your application.

[RB20JT]

anyone know the model numbers?