injectors central of the ram tube

[Celica RA45]

was thinking of running a 2stage system with injectors in head say to 5000 rpm and then the 1s in the center of the ram tube to take over what are the pros and cons of doing this also will i pick up more horse power as well thanks for any imput

[merc-blue]

the system works, i know that much,
The Supertourers used to do it, and there was big money spent designing and developing them,
We have a 1 of the 2 BMW E37 supertourers, CF everything (even tail shaft)

when you spend as much on a car as they did on this you assume that things they are using works.

although i think you need to get the injector angle and distance and spray patten all worked out

[MWP]

Also look at F1 setups... they all spray from just above or inside the trumpet.

Only problem is that newer F1 injectors spray continuously so they can be very small in size an not disrupt air-flow too much.
I think this will be your problem... finding injectors and working out a setup small enough that you dont create too much air turbulence or impede the air flow.

[kingmick]

you can do it, but to get the horsepower benefit you need to move them in and out on engine dyno to get them right! been used for years on v8supercars,touring cars,lemans and sportsedans etc.
it can be a bit hairy at times with that amount of fuel outside the trumpets! unless its all inclosed and even then i wouldnt do it to a street car.

[merc-blue]

if anyone has seen mech injection go bad you will understand what KM is talking about.
Saw a formula 5000 on a down shift end up on fire due to spraying fuel straight into the top of the slide and have it go everywere

a good way to play with lengths would be to cut your trumpets and use silicon tube and hoselcamps to play with length and then fab up your new trumpets bassed on that

[thechuckster]

get issue 7 of Race Magazine - has an article about James Augustine's VB cosworth engine that has the injectors at the stock location (below the the throttle) and larger injectors up at the mouth of the trumpet. Article has a lot of info about the fuel management of these two banks of injectors

His motec mixes the 'balance' of injector dutry from the two sets- based on rpm and tps position (megasquirt could do this based on load and rpm but you'd have to run each bank of 4 off one injector driver). There's more dyno/testing required to get this to work.

[thechuckster]

The F1 injectors are controlled, not 100% open. However, F1 run much higher fuel-line pressures and the volume/flow of air coming into the engine is way different to most race cars so issues relating to inversion-clouds and wet runner above the throttle are dealt with differently.

[merc-blue]

Race magazine is my favorite motorsport magazine ATM, doesnt focus on V8s or yobbos in commos and honndas and has great tech artivles

[gianttomato]

Glenn, you have enough power. You need more torque from 4000 - 5000.

get issue 7 of Race Magazine - has an article about James Augustine's VB cosworth engine that has the injectors at the stock location (below the the throttle) and larger injectors up at the mouth of the trumpet. Article has a lot of info about the fuel management of these two banks of injectors

His motec mixes the 'balance' of injector dutry from the two sets- based on rpm and tps position (megasquirt could do this based on load and rpm but you'd have to run each bank of 4 off one injector driver). There's more dyno/testing required to get this to work.

I'll photocopy it for him. It's a great read.

[Celica RA45]

has got the torque back and have power up to 183 kws just looking at the big picture of dry sump and 2 stage injectors looking for 200 kws at back wheels

[Celica RA45]

and i have 8 injector drivers as well

[thechuckster]

you could probably get away with smaller injectors up at the top of longer ram tubes to compliment the existing squirters. Particularly if you're just looking for a bit more power.

Augustine's approach is different, he has smaller injectors near the head - for mostly low rpm/load use - so he can get smoother engine down low then the larger squirters (at the top of the tube) up towards the louder end of the load/rpm scale. A significant proportion of the tps/rpm map has both sets of injectors working, but in varying segrees of propotion.

[ed]

glenn - look into old stubby mechanical injector nozzles.... see what different flows you can get at a rail pressure of 45spi. dont pulse them, just turn them wide open to supply the 'bulk' of your fuel at WOT, then 'tune' up to the actual fuel requirements using the manifold injectors at the same time.

[MWP]

glenn - look into old stubby mechanical injector nozzles.... see what different flows you can get at a rail pressure of 45spi. dont pulse them, just turn them wide open to supply the 'bulk' of your fuel at WOT, then 'tune' up to the actual fuel requirements using the manifold injectors at the same time.

Nice thinking... this would definatley be the best way to do it.

[gianttomato]

I must admit I'm a little nervous about a cylinder getting its fuel from two injectors.

It's all beer and skittles when they're both healthy, but should one fail, then I always wonder what molten aluminium might look like abrading a cylinder bore at 7000+ rpm.