Additional Injectors

[colin5524]

Well ran my garage floor a couple of days so the project will be starting soon, just a quick question on additional injectors, i have the machinery to drill and machine the intake manifold and wondered if i just got a set of additional injectors installed,not sure how big i should go (any suggestions if i go this route), as i will be using an aftermarket ecu.
Any ideas,experience,thoughts.....

[peterwolds]

twin 550\'s fitted by Pip at wgt,uprated fuel pump at same time

[colin5524]

Nice pic, what were you running turbo and ecu wise and how much bhp, were your primary and secondary injectors still standard

[peterwolds]

Nice pic, what were you running turbo and ecu wise and how much bhp, were your primary and secondary injectors still standard

Cheers
Bay looks better since that pic,new filters on and plenum polished.
twin turbos,apexi ecu/commander 305rwhp, 360 fwhp,primary/secondary 550/850\'s

[grinder]

is this for a FC or FD ( just that you have posted in the FC section but the pic in the thread is a FD )

[colin5524]

it will be for an fc but any ideas is good

[peterwolds]

is this for a FC or FD ( just that you have posted in the FC section but the pic in the thread is a FD )

dickhead here didnt spot was 2nd gen topic - its a bugger when you get old :evillaugh

[grinder]

on a FC if you put an extra set of 550\'s in that should see everything fine

you would then have 1650cc of injectors to play with

OR

put 720\'s in the secondaries and put the 550\'s as the extra ones

this would get you 1820 or injectors

some of the high BHP FD\'s only run 550\'s and 1600\'s - so thats 2150 - and its not cheap to get 400+ out of a FC

Stu

[Prof]

The real issue on the FC is fuelling - the stock fuel pump / wiring to the fuel pump are poo for big power:
 
Upto 280 BHP Stock pump (although filter changes - Hi and Lo pressure) recommended, and consider rewiring the fuel pump with thicker wire.
 
http://www.1300cc.com/howto/how2/rewire.htm
 
The stock primaries don\'t go much about 40% injector duty once the secondaries kick in - using an aftermarket or chipped ECU will get more out of these.
 
A link to Injector calculator: http://www.mazdarotaryclub.com/forums/showthread.php?t=30430&highlight=injector+calculator
 
For 300+ BHP you need to think about an aftermarket pump :
 
Choices are FD pump - good to about mid 300\'s, Walboro again mid to high 300\'s, Bosch 040 or Skyline pump for serious power - like 500+
 
Fuel lines are good for upto 500, but the stock fuel system has the primaries and secondaries fed in series from the pump, for 400+ power you should consider a parallel system.
 
http://www.mazdarotaryclub.com/forums/showthread.php?t=26511&highlight=fuel
 
There are other items that need to be addressed for making more than 300BHP from an FC - cooling (RAD and intercooler), Air flow (Inlet, Turbo, Exhaust), ECU replacement to mention but a few !
 
Following link on the FCS3PRO site has some good step by step guides for boosting the power:
 
http://fc3spro.com/TECH/FM2W/power.htm
 
Follow the Kouki links for an S5 Turbo II (European spec) engine

[colin5524]

Thanks for the info guys good stuff, just wondered who actually uses additional injectors apposed to bigger secondaries?

[Prof]

It depends a lot on what you have, what you\'re looking for in terms of power and delivery of that power (all or nothing, or nice and gradual / driveable).
 
You can make the existing injectors larger - but you need to adjust fuelling to do that and that requires a piggy back ECU or replacement ECU.  You don\'t really want to make the primaries bigger as it makes idle control very lumpy - really large primaries are hardly ever on at idle so they might even fire only on alternate cycles.  Keeping the stock primaries or going to 800/850\'s is probably about all you want to do.
 
Plenty of scope for increasing the secondaries - and if you go all the way to 1600, then you can theoritcally make 500+ BHP.
 
Alternatively, you can leave the stock injectors alone and add additional injectors and a small off board controller linked to boost / RPM / Throttle to control the extra fuel.  This works reasonably well because when the extra injectors are needed, the ECU is already working in open loop anyway (not controlling fuelling with the lambda - just using fixed map points based on boost / RPM / Throttle / Temp ).
 
A lot of the aftermaket ECU\'s and some piggy backs allow control of additional injectors as well, and you have much more integrated control of what\'s going on - far less likely to get rich or lean spots that can\'t be easily mapped out.
 
So if you\'ve already got an injector controller - consider using additional injectors  - 550\'s are dead cheap because people replace them
 
If your starting from scratch - look at ECU first, then consider larger secondaries - this is the route I am taking.

[colin5524]

Well i will be getting a ecu,not decided yet what are you running, so just get bigger secondaries would be the way to go.Looking for around 400bhp all fueling,cooling will be upgraded etc.Also what sort of porting are you running as this is somthing im still unsure of what direction to go

[Prof]

I have a street ported engine and will be running Greddy Ultimate Emanage piggy back.  I plan to initially keep the 550 primaries and upgrade the secondaries to 800\'s.  Longer term I might push the primaries to 800\'s as well - but depends on how the cooling works out.
 
Bigger turbo (hybrid T04B), Intercooler, Water Injection for the cooling.  I already had the exhaust system (Racing Beat), and I have modified the inlet ducting - much straighter path.  Need to make a cold air box for the HKS filter to sit in.  Experimenting with a water sprayer for the top mount ARC intercooler - I can run that and the WI from the eManage - which keeps all the control in one place.
 
Longer term I may consider a chargecooler - I don\'t want to go front mount, as I want to keep the piping short, and the car looking stockish at the front - bit of a sleeper