C20LET injectors upgrade

[avantrax]

I need to upgrade my injectors cause i think are close to the maximum they can provide

Actually i'm running the classic Bosch 0280 156 280
470ccm @ 3.0bar & 575ccm @ 4.5bar
High Impedance 14.2 Ohms

But i don't would like to run over 3.5/3.8 bar (or i'm wrong?)
Anyway my fuel pressure regulator can give since 4.7 bar and i have a Sytec fuel pump 255 l/h

The purpose would be a setup ready for 400/420 HP no more


I was thinking about these injectors

Siemens DEKA 630cc
low 630cc/ml/min @ 3bar
- 4 hole orifice
- Length: 75mm long version
- Cone type spray pattern, angle 26 degrees
- 12 ohm, high impedance
- Opening time 1.3ms / closing time 0.7ms
- Connector: Old style Junior Timer (AMP/TYCO)

Siemens DEKA 840cc
Flow 840cc/ml/min @ 3bar
- 1 hole orifice
- Length: 75mm long version
- Narrow cone type spray pattern, angle 10-15 degrees
- 12 ohm, high impedance
- Opening time 1.3ms / closing time 0.7ms
- Connector: Old style Junior Timer (AMP/TYCO)

Siemens / Mototron DEKA IV
Static Flow Rate: 80lb/hr = 875 cc/min
Dynamic Flow Rate : 18.6 mg/pulse 2.5ms PW, 20 ms Period
Coil Resistance: 12 Ohms
Connector: Bosch EV1
Series: DEKA 4 ( DEKA IV )
O-Ring Type: Viton

I think all are the standard bosch type injectors 60mm O-ring to O-ring
The price is about 160/180 GBP for a full set of four


Second question: i can drive these injector by the Motronic M2.7 engine management (obviously remapped)?

[cmac86]

I think the Deka 630cc's are good for about the 500bhp mark @ 3bar

I'm also running the 470cc's with a GT28 and they are maxed out at just over 330bhp on the Motronic. I'll be upgrading to the 630's when I eventually want more power. Not too sure how the 630's will run with chips though. I'll be going stand alone in the future I think.

[avantrax]

Yes i suppose my injectror fuel since the same amount of power

[c20letian]

isnt bigger better? 840cc all the way and then turn down the fuel pressure..

[dewismotorsport]

isnt bigger better? 840cc all the way and then turn down the fuel pressure..

Not on standard management no cause you get a crap idle

And I'd say 660's will be perfect For what you want

[c20letian]

personally i don't care about idle. but when i finish my car i wont drive it that much.

[Adam]

isnt bigger better? 840cc all the way and then turn down the fuel pressure..

I was running MSD 550cc's injectors @ 3.0bar fuel on a gt3071r at 1.65bar of boost at approx 400bhp on Vmax Evo5 chips all fine here

[Adam]

isnt bigger better? 840cc all the way and then turn down the fuel pressure..

I bought and tried 660cc's Siemens Dakar injectors and the car wudnt even run right...i.e. wudnt start and hold idle lol so sold them and wacked in MSD 550cc injectors and all was gravy.

[c20letian]

this is good ****... my old friend that has a 512bhp GT4 once told me that... sillycars are made different?

[Adam]

matter of speach? lol

[cmac86]

I was running MSD 550cc's injectors @ 3.0bar fuel on a gt3071r at 1.65bar of boost at approx 400bhp on Vmax Evo5 chips all fine here

Did you change the MAP sensor or was it factory? Might be worth me upgrading my injectors to see if I can squeeze more power on the Phase chips. I'm running Evo 5 and the VXR's are 100% duty at 1.2 bar of boost.

[Adam]

Dont need to change map sensor on Vmax Evo5 software...but I will be doing with my new software @ 3bar map sensor. I was running vxr injectors before but went for the msd 550cc's then.

[cmac86]

Sweet, cheers. Did you upgrade to the 550's because you maxxed the VXR's?

[avantrax]

I was running MSD 550cc's injectors @ 3.0bar fuel on a gt3071r at 1.65bar of boost at approx 400bhp on Vmax Evo5 chips all fine here

This is a great result for 550 injector
According to some injector calculation i supposed that at 3 bar would need a minimum of 630 cc/min injectors ... better go to about 800... but i'm not an expert about that

[avantrax]

Dont need to change map sensor on Vmax Evo5 software...but I will be doing with my new software @ 3bar map sensor. I was running vxr injectors before but went for the msd 550cc's then.

I was quite sure that M2.7 could not andle boost over 1.2 bar with its standard MAP sensor.
I read also something about an "internal" limit of a 0.9 loop but not sure of the meaning

[dewismotorsport]

personally i don't care about idle. but when i finish my car i wont drive it that much.

That's up to you but if a car can't idle its more likely to stall etc

What's the car used for? As if it's his every day car I'm pretty sure he wants it to idle properly, you can get away with the 550lb (525cc) MSD injectors on the later chip sets i.e evo 5, phase 3.5 & 4 but for 400bhp the duration on the injectors are running near there max so 670's would be my choice but only if your on aftermarket

[avantrax]

Whats the motronic limit for bigger injectors than 550?

[Topbuzz]

personally i don't care about idle. but when i finish my car i wont drive it that much.

Remember you have to get the car through the UK MoT if you want to drive it on the road (unless its a track day car), any more than 1000rpm and its fail (this is the trouble I had). Increasing fuel pressure/rate will likely make your engine idle high.

[avantrax]

I use my Astra only for track day use
no MOT, no public streets.

[Adam]

Sweet, cheers. Did you upgrade to the 550's because you maxxed the VXR's?

I was running the vmax evo5 on the vxr's for quite awhile but as I was raising boost finding its limits I came across sum 550cc's and felt the more leeway the better so in words to that effect yeah matey

This is a great result for 550 injector
According to some injector calculation i supposed that at 3 bar would need a minimum of 630 cc/min injectors ... better go to about 800... but i'm not an expert about that

You might be right but I am just going on what my afr wideband was telling me that all was ok on boost with the injector flow.

Whats the motronic limit for bigger injectors than 550?

I tried siemens 660cc's and the car wudnt idle lol though it cud of been a funked amal valve at the time because I did have problems with that but got pissed off took them out and wacked the 550cc's back in and ran fine...so maybe it wasnt the amal valve...phuck knows bloody c20lets..enuff said!

[avantrax]

Other ?

[TigraTurbo]

siemens 630 here at 3bar,they do good so far.

[Gordo]

As said, the problem with big injectors is accurately mapping the fuel for low flow conditions (idle). Dropping the fuel pressure may not help, either, as insufficient pressure may compromise the spray pattern.
IIRC, some injector brands/designs are better for this than others.
This problem is the main reason for using two injectors per cylinder for high power engines that also need good idle and emissions control. low fuel demend can be met by one and when higher fuelling is required, the second can suppliment it.

[pet007]

I have Deka 630cc for sale right now (they are already small for my target, I've made 360PS@E85 with them - see my project page). PM me if you have an interest...

[avantrax]

As said, the problem with big injectors is accurately mapping the fuel for low flow conditions (idle). Dropping the fuel pressure may not help, either, as insufficient pressure may compromise the spray pattern.
IIRC, some injector brands/designs are better for this than others.
This problem is the main reason for using two injectors per cylinder for high power engines that also need good idle and emissions control. low fuel demend can be met by one and when higher fuelling is required, the second can suppliment it.

Ok thanks for the info :-)