Fuel system mods for big bore 1400cc

Carlcouk

Registered
Can anyone advise me on the best type and size of injectors to use to gain pressure increase on a modified 1400cc busa engine please? Also would I require a bigger higher pressure fuel pump?

Many thanks
 
It's making 207bhp at the wheels but I know that with bigger injectors and an increase in fuel pressure it will make another (usable) 10+ bhp on top of that. I've heard that Mitsubishi 9 hole injectors are the best but just wanted to see if anyone has actually done this and what the exact models they used.
 
I've used other injectors but that was when I was at the 260hp mark. I only did this to get the fuel pressure down from the 60's to the 40's again. 220hp can be done by simply increasing the fuel pressure. You can do this by "pinching" the OE reg to increase the pressure or go to an aftermarket reg.

There are injectors out there that can work wonders for a fuel system when you need to flow really big cc's. I can dig up the companies name but they're really for the +700hp turbo engines.
 
Thanks so much for the advice!

So all I need to do is increase the regulator pressure and the standard injectors will suffice? I thought that more holes in the injectors would produce a more broader spray pattern thus increasing oxygen levels, is that not so?
Did you do this mod yourself or get someone else to do it? I would be interested in looking into new injectors so if you do have any contacts I could get in touch with that would be great.

Many thanks again.
 
I went the route of an aftermarket regulator myself. The stock injectors with added psi will handle your fuel with no issues. I'm not sure what you mean about the injectors adding to the level of oxygen so I can only answer by saying no, injectors don't influence the level of oxygen. The top line injectors are made by injector dynamics. The smallest ones flow 715cc. Again, these are intended for turbo apps that require a large volume of fuel. You can talk to the guys at T1race development who have plenty of hands on experience with these injectors.
 
Just fit s2000 injectors.50% bigger and drop
Straight in,your duty cycle will drop so the
Fuel rail has longer to recouperate pressure
And the lower duty cycle will make the injectors
Happier.as the fuel pressure will be stock
The pump will be happier and when the
Injectors start to outflow the pump at 43psi
The rail pressure drops and the pumps
Flow rate increases, of which you will have
Ample duty cycle left to tap into.
 
Thanks for the advice guys, greatly appreciated. Will let you know how I get on!

One last question, with the fuel mod (S2000 inj, increased reg etc) what else would I need to do to be able to attach a nitro kit? And what would be the best type of progressive kit to use for everyday road riding?

Many thanks
 
Here is a diagram of fuel reg crush mod

It's where you use a deep well socket that is about the same size of the internal spring. You place it on top of the regulator where the vacuum inlet resides and tap it lightly with a hammer to help compress the internal spring more than it was. This is a trial and error situation as you don't want to go crazy on tapping it too hard as it is a one time deal that cannot be reversed. Try a few light taps and reinstall on the bike and check the FP with a gauge until the desired static pressure is met. The pressure essentially allows more fuel at idle as well as under WOT. A cheap substitution for a littler larger injector or for that tiny bit of extra fuel needed. The stock injectors at 42psi are good for maybe 230hp. With it bumped up to 55psi, you can support another 20hp+ if needed. Keep in mind that you still need to map the ECU accordingly.

Here is a simple drawing of a FPR and where you crush it.


used 110 percent as its about a 12 percent fuel flow increase from 42 to 55 psi.
 
sorri pic did not upload

clip_image001.jpg
 
Dont tap with a hammer as instructions, put in a vice with dial indicator and only crush 0.30in to 0.32in ( 0.76 -0.81 mm ) any more and you start to run the risk of damaging beyond repair and having to replace it.
 
When you mention "nitro" I assume you mean a nitrous oxide kit. This really isn't the best option for extra power on a everyday street bike. If you're going this route a simply dry kit will be fine. There are lots of them on the market. A small shot doesn't need to be progressive either. Just inrease your line length from the solenoid to the injection point to soften the "hit".

I would suggest first getting your engine build sorted and play around with that power level before you start adding nitrous into the mix.
 
hi , i have 2006 busa engine but the engine have 1mm both valve 2mm crankshaft 2008 porting head and 240lbs compresion i will like if i need change the factory injector:sulk:
 
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