Hi,

I cut this from a post that appeared a while back:

The cream injectors (Bosch 0 280 150 744) are apparently only rated at 214cc/min at the default 2.5 bar, yet SBD retain them for their 208 kit.

If you look at the formula to estimate required flow rate for a given power (e.g. http://www.injector.com/injectorselection.php ) then these need to be run at around 95% duty cycle to achieve the stock 155bhp output. To get the recommended 80% max duty cycle would seem to require the pressure raised to around 3.5bar.


Well I am running the standard cream injectors and fuel rail/regulator and I am reluctant to spend loads of money on it at the moment. Does this mean that I am limited to 155 BHP? As this seems low considering that the widely quoted 180 BHP figure is available with carbs and the 8V ignition setup. If I need new injectors then what would be the best ones to go for?

Those Calculators don't seem quite right really.

I know the flow rates for our standard Pinto injectors (165CC/min and 115bhp?) and for the R1 injectors (225CC/min and 160bhp) and both using that calculator are about upto their max.

What setup are you intending on running?
I should imagine a simple upgrade for the XE would be the LET injectors

I am intending to run a standard Redtop XE with GSXR TBs fitted to a modified inlet manifold with the XE cream injectors and original fuel rail.

How would I know what the LET injectors are if I started to search on ebay?

No need for any more injectors then.

MegasquirtNspark can run staged injection.....

Ours is setup that it uses the Ford injectors that are close to the head until 3000 rpm and then phases the R1 injectors in as well.
Can't remember off the top of my head if is switches over to the R1 injectors completely or runs them both.
This could give us upto 390cc/min which should be more than enough!

Have a read up about "staged injection" and see what you can find.. it takes a bit more plumbing and will probably require a different fuel rail making for the bike Tb's

I'm running (or will eventually) gsxr bodies with the std keihn injectors on my xe . Also someone posted recently with a dyno run showing 200bhp using an xe with std internals and gsxr bodies so I don't think it'll be a problem.

I'm using the GSXR injectors @ 3 bar.

My current plan is to use the GSXR injectors (possibly about 240cc/min?) as the manifold I have doesn't currently have injector bosses.

I wouldn't pay too much attention to the calculator, it always oversizes injectors. If you plug in the factory power outputs for quite a few popular engines it always decides the OEM injectors are too diddly. I imagine it has something to do with it allowing for hideously in-efficient 70's american engines and so assumes a BSFC much worse than found in most modern four-valve engines.