Subpage of MembersPage/MarcellGal/PowerAndTraction
Injector
Brave men do like this: in audi 5cyl 20vt thmb rule: cc/per injector = max power in hp. 440cc = 440 HP
I think it's brave. But with tuned boostcontrol it can be tried. If going up slowly, one will know when running out of injectors flowrate.
I think there is an error on http://www.rceng.com/technical.htm they swapped the BSFC for turbo and supercharged. Turbo is better (lower). Below I calculate with BSFC(gasoline)=0.55l / (HP * l), consistent with some other sources.
examples
- For factory 220 Hp 220 * 0.55 / (5*0.8) * 10.5 = 317cc/min (they used 350cc/min)
- Teppo Kalske used to have 460cc with wich ended up 100% dc at 5000 rpm with reasonable afr (580Nm/3800, 440hp/6800). Prolly maxed out near 400 HP:
- for 400 HP, even with 100% duty: 400 * 0.55 / (5*1) * 10.5 = 462 cc/min needed
- <Jorgen__> It's recommended but not needed.
- or in other words 360 * 0.55 / (5*1) * 10.5 = 415 cc/min (enough for 360 HP) is enough to start with but will not get max power
- 420 HP with 80% duty and pessimistic BSFC=0.63: 420* 0.63 / (5*0.8)* 10.5 = 694.58 cc/min (so the 599cc/min@3bar injectors are enough for this engine)
Jorgen's note: If the stock injectors is 350cc the 415cc injectors in the webshop is almost identical in size. (good point!) 350cc/min@3bar is same as 404cc/min@4bar: 350 * sqrt(4/3) = 404.15 Then we can use the stock injectors instead, at 4bar fuel pressure of course.
Jorgen will check if he finds a 4bar regulator for me (isn't it just a stiffer spring inside the FPR?).
Safe injector sizing
If purchasing new injectors, it is best to have it sized high enough to be enough for sure, for the times to come.
The injector sizing should be rather 420 HP with K26/27 turbo (even if we'll more likely get only 370 HP).
- emil recommends [L107FM] to most people, except the insane ones. Static Flow Rate: 60 lb/hr @ 43.5PSI (300kPa) = 630cc/hr (price: 5 * $55 USD+shipping)
- Wide angle spray pattern (is that good?)
- [old Bosch-style Siemens injector] has Static Flow Rate (GAS): 57 lb/hr @ 43.5PSI (300kPa) = 599cc/hr
- Pencil beam spray pattern (is that good?)
- this Bosch-style injector has MUCH wider body than the slim L107FM. Also, 1mm longer! (that should not cause a problem, right?)
- Price is slightly higher: 5 * $57.49 USD + shipping
- both injectors sit in 14mm drill, and have AMP connector.
Which is the better choice ?
Fuel Pump
Kalske's hints in this case is to use 044 pump in PnP install inside fuel tank
- 895201531A strainer
- 895201779H reservoir mount
- N 90330701 banjo union
- N 0138128 2pc seal
- N 0110691 domed cap nut
First two are the most important ones, they are used fitting the pump in place of the original one. Banjo, seals and nut are used for fuel line connection.
What is the hard part without these ? I think Nanassy and Karkus will probably handle this, but I really don't know about the potential complications.