Got my body back..........!

[ibizacupra]

unfortunately because i run with regular injectors i have had to limit fuel pressure to only 12bar, if i was to splash out on TAG injectors (@ £550 a pop x 8!) i would be able to go to the fuell 16bar the system is capable of (and hence gain another 5 to 8 bhp)

just proves that:

"how fast do you want to go" = " how much money have you got"!!


lol

12bar! what boost pressure is your motor going to be running at then Paul?
max boost +3bar fuel pressure...
I cant imagine what size injectors your using on those kind of fuel pressures... Is it direct injection of something?

 

[Triple D]

Its N/A afaik isnt it? not turbocharged. or am i wrong?

 

[Triple D]

erm actually bill, im being a twat, just looked at the pics on page 1 and there is a huge big f*ck off turbo on there, my bad

 

[max_torque]

Nah Bill it's not DI, just regular port injected. but in order to keep pulse width short so i can get all the fuel in on an open valve, and maximise fuel atomisation i run with big fuel pressure on small (ish) injectors (330 cc/min @ 4 bar, about 560cc/min @ 12 bar)

Peak boost is currently cal'd in at 2.7 bar gauge (3.7 abs) but it might get knocked back in the lower gears to enable the car to get some traction. boost at peak power rpm depends on if the FIA inlet restrictor is fitted or not, basically it's just about 2 bar when not restricted and only 1 bar when restricted.

 

[RobT]

presumably these need to be special injectors to take this pressure ? got any pics ? presumably they are not just push into a rail with o'ring seals - bet you get cracking atomisation though....fancy this for my motor

 

[David_smith_909]

just seen this thread

WOW, full respect

 

[ibizacupra]

Nah Bill it's not DI, just regular port injected. but in order to keep pulse width short so i can get all the fuel in on an open valve, and maximise fuel atomisation i run with big fuel pressure on small (ish) injectors (330 cc/min @ 4 bar, about 560cc/min @ 12 bar)

Peak boost is currently cal'd in at 2.7 bar gauge (3.7 abs) but it might get knocked back in the lower gears to enable the car to get some traction. boost at peak power rpm depends on if the FIA inlet restrictor is fitted or not, basically it's just about 2 bar when not restricted and only 1 bar when restricted.

Hmmm interesting stuff..
mine are 750cc injectors @ 3bar currently, but run 2.2bar peak boost, 2bar at 8200rpm current limiter.
pulse width short is good beacuse?

 

[max_torque]

Hmmm interesting stuff..
mine are 750cc injectors @ 3bar currently, but run 2.2bar peak boost, 2bar at 8200rpm current limiter.
pulse width short is good beacuse?

On a port injected engine (rather than a DI one) you have to get the fuel and air past the inlet valve. As the air is a lot less desne than the fuel it's the engines volumetric efficiency on it's charger air that is the limiting factor (well it is until you get up to methanol buring top fuel dragsters lol!) hence even on a turbo engine, if you can increase the air ingested during each induction stroke you can increase cylinder filling, add more fuel and get more power out. If you are simply chasing max power, rather than idle stability or emissions you need to only inject on an open inlet valve as fuel siting on the valve and evaporating displaces charge air (and actually reduces the valves flow at low lifts). As you increase the rpm of peak power your valve open event duration decreases, so you need increasing injector flow to have a short enough injection event. If you fit big injectors running at low pressures you tend to find that atomisation becomes a problem, and brake specific fuel consumption plumets (you still get the power pretty much, but use a lot of fuel doing it as most of it sits in the form of liquid or over rich vapour, only to be burn out the tailpipe)
so the best trend is to ise good atomisation injectors runing at high pressure, hence wrc engines run port injected at approx 16bar, and F1 engines run port injected at 50+ bar! (a modern F1 engine is practically a DI with a pencil jet injector shooting past the valve into a controlled arear of the chamber)

For ultra high performance NA engines (8500rpm+) there is a trade off in terms of running remote injectors which give the fuel plenty of time to evaporate and also provide a degree of air charge cooling (which increases charge density, but usually requires injectors 200mm or more upstream of the valve)

I run with std bosch injectors, with std O rings, but beefed up retaining clips (although there is only approx 200N pushing the injectors out of the rail) i do run with a clever fuel injector driver system, that effectively mimics a peak and hold system to over drive the injectors to get them open as fast as possible against the fuel pressure. Injector life i hear you ask?? er, good question, i'm expecting about 1000km before new ones are needed!

hope that helps!

 

[andyj]

think I got the jist of that...

top work though matey.....

looking forward to seeing it run eventually !!

 

[ibizacupra]

On a port injected engine (rather than a DI one) you have to get the fuel and air past the inlet valve. As the air is a lot less desne than the fuel it's the engines volumetric efficiency on it's charger air that is the limiting factor (well it is until you get up to methanol buring top fuel dragsters lol!) hence even on a turbo engine, if you can increase the air ingested during each induction stroke you can increase cylinder filling, add more fuel and get more power out. If you are simply chasing max power, rather than idle stability or emissions you need to only inject on an open inlet valve as fuel siting on the valve and evaporating displaces charge air (and actually reduces the valves flow at low lifts). As you increase the rpm of peak power your valve open event duration decreases, so you need increasing injector flow to have a short enough injection event. If you fit big injectors running at low pressures you tend to find that atomisation becomes a problem, and brake specific fuel consumption plumets (you still get the power pretty much, but use a lot of fuel doing it as most of it sits in the form of liquid or over rich vapour, only to be burn out the tailpipe)
so the best trend is to ise good atomisation injectors runing at high pressure, hence wrc engines run port injected at approx 16bar, and F1 engines run port injected at 50+ bar! (a modern F1 engine is practically a DI with a pencil jet injector shooting past the valve into a controlled arear of the chamber)

For ultra high performance NA engines (8500rpm+) there is a trade off in terms of running remote injectors which give the fuel plenty of time to evaporate and also provide a degree of air charge cooling (which increases charge density, but usually requires injectors 200mm or more upstream of the valve)

I run with std bosch injectors, with std O rings, but beefed up retaining clips (although there is only approx 200N pushing the injectors out of the rail) i do run with a clever fuel injector driver system, that effectively mimics a peak and hold system to over drive the injectors to get them open as fast as possible against the fuel pressure. Injector life i hear you ask?? er, good question, i'm expecting about 1000km before new ones are needed!

hope that helps!

Thanks Paul.
What are your thoughts on my ibiza's motor and injection.
Running boost of 2.2bar peak, 2bar sustained on 750cc injectors currently on 3bar rail pressure. (likely to change to 4bar again as I have *cough* plans)
750cc genesis injectors with a dual cone spray.

What does your motor rev to?

 

[Mad Spoons]

Its going to be awseome, looking forward to some vids of it running

 

[max_torque]

Thanks Paul.
What are your thoughts on my ibiza's motor and injection.
Running boost of 2.2bar peak, 2bar sustained on 750cc injectors currently on 3bar rail pressure. (likely to change to 4bar again as I have *cough* plans)
750cc genesis injectors with a dual cone spray.

What does your motor rev to?

I imagine that you have a pretty big airflow and fuel flow, but not necessarily a great BSFC / BSAC (brake specific fuel / air consumpton) as i suspect you will be pretty det limited throughout the *** rev range. What fuel grade do you run / are you allowed to run?

also i guess that you are using a significant proportion of your injected fuel mass to simply cool your exhaust line components, as anything richer than about 0.85 lambda is costing you power.

I don't use as much fuel beacause i rely on the water injection to provide the cooling, and run to 0.85 lambda, with the water making up a "virtual" fuelling of about 0.72lambda (although due to the 4x specific heat capacity of water over gasoline i actually only need to inject something like 0.05 lambda worth of water (by volume)

Havent actually decided what peak rpm is going to be on my engine, my carbon prop is good for 12krpm (so theres a good target! lol) bottom end of engine should be good for circa 8.8krpm, on the current cams peak power (unrestricted) is about 7200.
I need to get the car up and running to determine if it will take a more agressive cam (in terms of boost threshold / driveability) and shift the torque curve up by 600rpm or so. When restricted peak power is flat between 4200 and 6600rpm!

 

[ibizacupra]

i am running v-power pump gas as this is "legal" however I know several other competitors who run race brew fuels 102+octane

I am running WI now again, basic pressure system and squirt it in. crude I know.

logging on vagcom I have only seen 1.5 to 3 degree timing pull on a couple of cylinders. Current limiter is 8200rpm on mine with a prospective +500rpm rise on the new turbo I'm running.

I am loosing power as my a/f is in the 0.7 level a lot of the time. EGT's are ok I think with WI running post turbine 880'C flat out so far.

ME7 limited - I am at a crossroads @ what to do next

 

[max_torque]

Finally got my Carbon prop from CTG, it's nice, but, er "reassuringly expensive" lol!

Turbo & Exhaust heat shielding going in:

Wires, pipes, stuff everywhere! lol

slow progress, but progress none the less.

 

[Ruddmeister]

Finally got my Carbon prop from CTG, it's nice, but, er "reassuringly expensive" lol!

Much like the rest of the project then

Nice work though and it is progressing well judging by the pictures

 

[ibizacupra]

Turbo & Exhaust heat shielding going in:

slow progress, but progress none the less.

Is your motor missing crank, rods, pistons Paul.

What turbo is that?

 

[andyj]

looks like it's missing a head as well......

tasty looking drive shaft though....

 

[max_torque]

Is your motor missing crank, rods, pistons Paul.

What turbo is that?

oh damm, knew i had forgotten something important!

actually thats my spare block and head which is just chucked in so i can route wires pipes and heat shields properly before the rear engine goes in!

The turbo is a real Bitza, much like the rest of the car, it's a sort of hybrid of T4 and GT series, running a genuine Cossie touring car (think Andy Rouse circa 1989 / 19990!) Grp A turbine housing a wheel (hand trimmed blades!,Myram 247 full ALS spec) and a T4 compressor housing, but with a large GT compressor wheel and a ball race CHRA. It was the best thing availible when i built my last Hi power engine, but i suspect it will get replaced with something a bit more modern in a bit (i run a TR-30 WRC spec garrett when 34mm inlet restricted)


like i said a real bitza, but good for 600+ bhp, if a bit laggy by modern stds below 5.5krpm.........

 

[m0rk]

good for 600+ bhp, if a bit laggy by modern stds below 5.5krpm.........

damn life sucks when you have 600bhp

it's going on well - I remember seeing this 1st when it was in it's infancy!

 

[traumapat]

awesome thread. inspired