5 laps @ 2 mins a lap...

i normally go through about 1/4 to a 1/5 tank of fuel in 10 mins...

 

Just in case you want to race, 12-litre should last 20 mins.

2x 1mm jet ~ 1000cc/min. @65% full throttle (12min/60%)

 

Hi Richard,

How do I know if I need 2 jets or just 1?

 

Please post pics

Thanks

 

I will

Once I get more stuff to take photos OF hehe

 

Use the following as a simple guide line:

- 100% water ........ 10-15% to fuel flow
- M50/W50 ......... 15-20% to fuel flow
- 100% methanol ........ 20-25% to fuel flow

You can go ourside those ratios but requires a more aggressive fuel trim.

 

I must be missing something.

4x 560cc injectors (running *almost* flat out - 95% DC)

= 2240cc/min

50/50 MIX - so 20% replacement results in 448cc/min for the meth.

However the chart shows I should be using the 0.8 injector nozzle for 20-25psi of boost...

So I don't really understand what the requirements are for the second nozzle - is it when you require more flow than the 1.0 nozzle can supply?

 

Tephra, check out the alky flow calculator I posted in this section a while back, it will help you decide how much to run. I ran a single 1.0mm jet on a stock IX turbo and it worked out fantastic. On the BBK setup I'm running a 1.0mm & a .9mm jet. Remember that injecting near the TB will increase effective octane, and further from the TB will increase effective charge cooling. I decided to compromise and continue to run the one near the TB (ran my 1.0mm at this location) and run a second further down the UICP just under the intake, in front of the tranny. I figured this gave me the best of both worlds. IMHO you should consider running something like 2x .5mm jets in a similar fashion. Doing much more than that will be overkill--this isn't necessarily bad, but it definitely eats through your supply tank(s) more quickly!

As far as tank mounting, I'd just look for some 1x 1/8" lengths of aluminum and mount the tanks to that. Check out some of the installs by SlowCar (abner) on here, lots of great mounting ideas that I think could apply to the space in the X that is already sectioned off--especially if you installed a mini-battery!

 

does the smaller jet provide a more mistier spray?

ie is 2x 0.5 is better than 1x 1.0?

 

Tephra,

The chart on the HFS-6 is the maximum size jet without a tune. I don't think if will suit you.

 

Hi Richard,

what do you mean by "without a tune"?

*confused*

ok lets start again.

If I know:
a) injector size + number (560/4 @ 95% IDC)
b) max boost pressure (25 peak, 20 @ redline)
c) meth mix and replacement % (50/50 Mix, 20% replacement)

How do I:
a) calculate what nozzle size I need?
b) tell whether I need 1 or 2 nozzles?
c) tell if I need a restrictor or not?

Cheers
David

 

a) I can only recommend jet sizes in general that will not affect an engine without a tune for obvious reasons.
b) Without tune- 1 nozzle. With tune- anythings goes - 2 noxzzles for sure
c) Restrictor used is for match the final niozzle size. This is to keep the dynamic range linear.

The current FCM is capable of injeting 1600cc/min. Way beyond a two-jet setup. Without matching the restrictor, you will over inject at low duty cycle. We might reduce the flow of the FCM in the near future. We have a few problems with people getting a good lineraity with one jet. I think 1000cc/min is good enough for most applictaions.

We have design the valve's pressure and flow capability a bit too far.

 

and by tune - you mean fiddling with AFR/timing/boost/mivec?

Well I thought it was fairly obvious that you need to tune for water/meth to get the most out of it.

So I will be having a tune

ok so going back to my specific application - the chart shows I should use a 0.8 jet:

560 * 4 = 2240
20% replacement = 2240 * 0.20 = 448cc

160 - 25psi, and find closest to 448 = 0.8 jet.

Is that correct for single jet?

So If I want to run 2x jet's instead of 1, do I just get 2 smaller jets to still make up roughly 448cc/min for my boost level?

ie 2x 0.4 jet (@25psi) = 430cc/min

 

Slowcar (abner) is a fine example, he ran 2x 1mm jet on an 100% methanol "on/off" system, stock turbo. With a tune, He gained something like 40HP and 70 TQ.

 

yeah thats around my target +50/+50 would be awesome

So is my reasoning/method above correct?