47 replies to this topic

[fezzasus]

They're not. Another way to look at it is the Lsj and Z20LET have the same factory power, but the green lsj injectors are better matched to the head

Edited by fezzasus, 16 April 2017 - 09:37 AM.

[chris_uk]

the greens hit 90% duty cycle at a lower power than the z20let ones do, that's what i found anyway,.

 

 

[Exmantaa]

the greens hit 90% duty cycle at a lower power than the z20let ones do, that's what i found anyway,.    

That's really weird as the Greens can deliver 11% more fuel than the Black Z20LET's... But in the end you should fit what you feel happy with.

Edited by Exmantaa, 16 April 2017 - 04:47 PM.

[chris_uk]

Yea i know. I will see if i can dig the logs out as i compared them back to back.

[CHILL Gone DUTCH]

Very Intresting Like frank says should have considerably more capacity but have noticed higher than expected DC from the green lsj injectors, Maybe there not as linear top end to bottom as the vxr or leh injectors If chris has the data on the same car we could see if lsj is better lower down the duty cycle Anyone know at what duty cycle the injectors are calculated there maximum duty cycle ?

[CHILL Gone DUTCH]

the greens hit 90% duty cycle at a lower power than the z20let ones do, that's what i found anyway,.    

That's really weird as the Greens can deliver 11% more fuel than the Black Z20LET's... But in the end you should fit what you feel happy with.

Frank I may not in a position to work it out for my self ATM But I've noticed a vxr ( blue ) injectors seems to have 20% better capacity than lsj Is this what you would expect between the 2

[Exmantaa]

Injectors are normally tested at 100% duty cycle, so continuous flow.

MarkV build his own injector test rig and tested various suitable injectors for OBD tuner at our rail pressure. (not only flow capacity, but more importantly the dynamic behaviour like delays/offset parameters.)

 

He came up with the actual measured flow data and found that the VXR injectors flow a bit less than they are advertised for. I never did a direct comparison between injectors...

[Rob3770]

I had green on my Stage two but when I fitted the full tullet I needed to upgrade to the blue as they were close to the limit..

[Nev]

I'd really try and avoid making your injectors work too hard, particularily on a lower powered car where you are likely to stay at/near max duty cycles for more time.

 

When I had my car mapped at CS initially they insisted on installing 630cc injectors even though I supplied them with 875cc injectors. I bowed to their "experience" and forked out £275 to them to let them put the smaller injectors in. When I got the car back (with a print out of the metrics) I calculated the duty cycle was 100% at max power, bloody crazy and showed how little experience they had with big power stuff. I also later discovered they had crushed my FPR to increase the fuel rail pressure and not told me.

 

Anyway, after about 10,000 miles of driving with this map I found my bores were glazed. As is often the case it's hard to pin point where this major problem came from, but a possible candidate was the badly matched injectors.

 

The reason I say this is that if your injectors are squirting for the majority of the time into a closed port then the atomised fuel can/will accumulate on the inlet runner side walls in liquid form - this is bad. In my case my runners pointed down to the ports, so this liquid fuel could drain onto the pistons and if not ignited would work it's way past the rings into the oil, and over time causing the glaze. On over run I would imagine this situation might be quite likely. Also, I noted that my oil used to smell of petrol strongly, so I performed a viscosity test on my used oil and compared to the new stuff it was indeed a lot thinner. This seemed to strengthen my bore wash theory.

 

Anyway, based on this real world experience, I would strongly suggest you never go over 75% duty cycle, and ideally stay below 60%.

 

HTH.

Edited by Nev, 17 April 2017 - 02:20 PM.

[The Batman]

you still running the 630cc nev? if so my baby NA has bigger injectors

[Nev]

you still running the 630cc nev? if so my baby NA has bigger injectors

 

No, first thing I did when I got the new ECU and map on my re-bored engine, was to install bigger 875cc injectors, these are ok for the 460 HP map, but a bit weedy for the 520 BHP one.

 

When I was on closed wastegate (the light blue lines on the graph below) and took the car to the rolling road at Castle Coombe the print outs showed it (optimisitcally) making 602 HP and pushing the injectors to almost 100% duty.

 

4 power runs (all at different boost levels):

 

4 duty cycles:

 

Edited by Nev, 17 April 2017 - 02:31 PM.

[The Batman]

ah beats me! CPL Racing fitted 750cc to mine (not sure on what the duty cycle is)

 

but think i may plan in a couple of engine mods this winter so will ask then

[Nev]

ah beats me! CPL Racing fitted 750cc to mine (not sure on what the duty cycle is)

 

but think i may plan in a couple of engine mods this winter so will ask then

 

Good, I expect your DC is nice and low as your engine is a 2.5 Litre NA.  

Edited by Nev, 17 April 2017 - 02:24 PM.

[The Batman]

I wish, 2.0 here Guy at cpl has 2.5 itb with water meth injection in his Civic and the power is unreal! But the price is absolutely mental I'm hoping to squeeze extra 30-40bhp out of the old gal this winter and stay NA... that's the plan anyway..

[The Batman]

Just seen your graphs why are the runs so different?

[Nev]

I wish, 2.0 here Guy at cpl has 2.5 itb with water meth injection in his Civic and the power is unreal! But the price is absolutely mental I'm hoping to squeeze extra 30-40bhp out of the old gal this winter and stay NA... that's the plan anyway..

 

I don't understand why you don't supercharge it to get your VE over 100%, presumably quite easy with all the established kits I imagine there are?

 

 

 

 

[Nev]

Just seen your graphs why are the runs so different?

 

Was testing with different boost levels using a MBC.

 

With the wastegate locked shut the car was undrivable as it was almost wheelying (no exaduration) in 2nd gear as the torque was circa 550 ft/lb. Even in 3rd and 4th gear it would easily spin up the rear wheels with warmed up 225mm R888s.

Edited by Nev, 17 April 2017 - 02:36 PM.

[The Batman]

there is alot of kits, the jackson charger eats through chargecooler cores, the rotrex kit is alright but lacks torque.

 

the engine itself is now good for massive power but there is something very satisfying as staying NA on track.. chill still gets away from me but im hoping extra 30/40bhp should stop that..

 

ideally i want a spare engine to have a play with sc but thats another project for another winter

[Nev]

there is alot of kits, the jackson charger eats through chargecooler cores, the rotrex kit is alright but lacks torque.

 

the engine itself is now good for massive power but there is something very satisfying as staying NA on track.. chill still gets away from me but im hoping extra 30/40bhp should stop that..

 

ideally i want a spare engine to have a play with sc but thats another project for another winter

 

Yea, I can understand enjoying a responsive low powered car for it's handling agility and also not to be scared to death by traction issues.

 

I think once you've had a ride with Lee's new engine and felt the rush, you'll be converted though, he should have the handling and the power.   

Edited by Nev, 17 April 2017 - 02:48 PM.

[The Batman]

i already know mines not the quickest, but its no slouch either.. will take you out for a spin at national, feel free to make a sandwich and read the local newspaper as i go round