Maxed Out Injectors - Possible To Swap ?

[SAM-32R]

I've just had my car tuned.. and the injectors were maxed out at 17psi

iam not sure wat size they are.. but iam assuming they are probably

550cc since they've already maxed out with that much boost....

i noe they arent standard as they are purple and not the standard yellow

just wanted to noe.. because the tunes already finished.. is it possible to just

throw in a larger set of injectors and set the injector size in the power fc

and it would justt run.. or would i need a complete re-tune ??

it's an R32 GTR

thanks in advance

Edited February 19, 2008 by SAM-32R

[TTT]

what power were you making when they maxed out?

[SAM-32R]

what power were you making when they maxed out?

pushed out 307kw at all four

[Devils_Advocate21]

You can throw a larger set in and possibly set the injector size to get it to the tuners, but ultimately you'll have to get a re-tune and check on the dyno as i think it would run mega rich with larger set in.

[R31Nismoid]

Sound like factory ones

550's would be fine for that power level considering stock ones can be pushed to that point.

If you do have after market injectors i would say fuel pump or blocked fuel filter etc etc.

(surely you'd know as you've gotta set-up the injectors in the ECU no?).

[TTT]

I haven't used it but if you can setup the injectors on the ecu, surely you can see what they are set to now.

[SAM-32R]

nah guys.. they cant be standard cause like i've said they've got the purple tops as opposed to the standard yellows

and cant be fuel pump or fuel filter as they are both brand new items

and on the computer the values currently set on the injector page are 70 and all injectors..

but then while driving and keeping an eye on the duty cycle on 17psi iam hitting 97%

soo that's my problem at the moment

also iam pretty sure they're denso injectors as they have denso on them with the purple tops

Edited February 19, 2008 by SAM-32R

[R31Nismoid]

Well Denso make injectors for just about everyone, so that doesnt help.

In all honesty you dont have 550's if your on 97% duty with 300 @ the treads. Its nowhere near it.

So its either they are around 440 (stock size), or you have something else wrong

New fuel pump doesnt mean a thing if the pressure isnt there, have you checked?

Is the pump getting the correct voltage?

[darrinspencer]

In all honesty you dont have 550's if your on 97% duty with 300 @ the treads. Its nowhere near it.

So its either they are around 440 (stock size), or you have something else wrong

Sam-32R quoted 307 KW at all four

Approx 60-70kw driveline loss

That works out to be approx 500hp at the engine

550cc good for approx 550hp

97% of 550's equals 533hp

Pretty close to 500hp with my calc's

Supprised to see 440cc making 500hp

Have I missed something?

[R31Nismoid]

Dude there is no such thing as 70kw loss from AWKW to RWKW a GTR is NOT fulltime 4WD

Its been proven time and time again (there are about 4-5 threads on it now)

There is bugger all difference is rwkw/awkw. Most people are within 10-15kw between the two modes.

[darrinspencer]

Dude there is no such thing as 70kw loss from AWKW to RWKW a GTR is NOT fulltime 4WD

Its been proven time and time again (there are about 4-5 threads on it now)

There is bugger all difference is rwkw/awkw. Most people are within 10-15kw between the two modes.

I agree

I was refering AWKW to engine KW. There is approx 60-70kw lost thru the drive train!

Suggest you READ my previous post again.

[R31Nismoid]

Go see the RB26 dyno results threads.

A few users have indeed run the stock GTR injectors to 300rwkw on more than one occasion.

So it would lead me to believe that a 70kw drivetrain loss is far from right. I mean, 20% power loss... Its nothing like that based on other past topics also.

550cc are good for 550hp as the base pressure.

Thats WELL in excess of 310rwkw. Much closer to 360rwkw safely.

[darrinspencer]

Go see the RB26 dyno results threads.

A few users have indeed run the stock GTR injectors to 300rwkw on more than one occasion.

So it would lead me to believe that a 70kw drivetrain loss is far from right. I mean, 20% power loss... Its nothing like that based on other past topics also.

550cc are good for 550hp as the base pressure.

Thats WELL in excess of 310rwkw. Much closer to 360rwkw safely.

To back my theory and a search as suggested, I quote from the guru Sydneykid

Quote-

Yep, but you can't run an engine with injectors at 100%, you need some overhead for acceleration enrichment and changing weather conditions. Around 80% is a good working maximum.

My rule of thumb in a 6 cylinder engine is injector cc's = bhp

444cc's = 444 bhp

divide by 1.34 for kw = 331 kw

subtract 55 rwkw for 2wd losses = 276 rwkw

or subtract 75rwkw for 4wd losses = 256 4wkw

End of quote

Sam-r32 is getting 307 4wkw!!!!

[Tangles]

looks like it is time to either

a) upgrade from 550 items to 700cc, and retune, then sell the 550 injectors - or

b) detune the engine

[eddieeeee-ro]

my mates r33 gtr was making 260awkw with standard injectors with 80% duty

[R31Nismoid]

To back my theory and a search as suggested, I quote from the guru Sydneykid

Quote-

Yep, but you can't run an engine with injectors at 100%, you need some overhead for acceleration enrichment and changing weather conditions. Around 80% is a good working maximum.

My rule of thumb in a 6 cylinder engine is injector cc's = bhp

444cc's = 444 bhp

divide by 1.34 for kw = 331 kw

subtract 55 rwkw for 2wd losses = 276 rwkw

or subtract 75rwkw for 4wd losses = 256 4wkw

End of quote

Sam-r32 is getting 307 4wkw!!!!

Buy using the own calculations provided

550cc = 550bhp

/ 1.34 = 410kw

-75 = 335rwkw

So its 30kw more (or nearly 50hp). So, with 335rwkw, 550cc injectors are at 80% DUTY CYCLE as per the calculations for 'most' cars.

So... again, what are you on about mate? I still dont get it.

Even with calculations that back me up, i still dont see where your figures and claims are coming from that 550cc injectors will be maxed out, let alone reaching 80%

550's would NOT be maxed out, and they are capable of a bucket load more power than 300awkw

edit: and stock injectors will get 300rwkw and be safe too. Its been done!

[darrinspencer]

Buy using the own calculations provided

550cc = 550bhp

/ 1.34 = 410kw

-75 = 335rwkw

So its 30kw more (or nearly 50hp). So, with 335rwkw, 550cc injectors are at 80% DUTY CYCLE as per the calculations for 'most' cars.

So... again, what are you on about mate? I still dont get it.

Even with calculations that back me up, i still dont see where your figures and claims are coming from that 550cc injectors will be maxed out, let alone reaching 80%

550's would NOT be maxed out, and they are capable of a bucket load more power than 300awkw

edit: and stock injectors will get 300rwkw and be safe too. Its been done!

307kw @ 97%

316kw @ 100%

316kw is not too far from your calc 335kw, esp when the 550hp start figure is just a rule of thumb.

A difference of just 19kw is what you are disagreeing over, which could just be a differnce in dyno's

The ONLY way for sure to prove any of this is for SAM-r32 to flow test his injectors to know what he has

Until then, WE can all only guess.

[R31Nismoid]

Where do you get 19 from?

Its 28kw actually (335-307), which might as well be 30rwkw for all it matters as its 80%. For each % its nothing to get excited about, you could run at 83-84% no problem and then all of a sudden your not far off 350rwkw and your 40kw difference then.

Its not guess work at all, he doesn't have anywhere near 550cc worth of injector flow if he is maxing out at 307kw, not in his wildest dreams.

[darrinspencer]

Where do you get 19 from?

Its 28kw actually (335-307), which might as well be 30rwkw for all it matters as its 80%. For each % its nothing to get excited about, you could run at 83-84% no problem and then all of a sudden your not far off 350rwkw and your 40kw difference then.

Its not guess work at all, he doesn't have anywhere near 550cc worth of injector flow if he is maxing out at 307kw, not in his wildest dreams.

550hp is the max hp from 550cc @ 100%cc, not at 80%

Since you were quoting 335kw MAX, I calc'd 97% @ 307kw to be 316kw @ 100% MAX

335kw minus 316kw is 19kw

A simple 19kw can be in difference dyno readings.

[R31Nismoid]

People have run 300rwkw (more than one car) with factory injectors

People have run 330rwkw with 550's

400rwkw on 600's

http://www.skylinesaustralia.com/forums/in...st&id=10860

370rwkw on 600's (and i know these werent even near the limit as i live with the guy that helped build it)

http://www.skylinesaustralia.com/forums/in...st&id=20109

Surely these two would be dead? I mean, as the limit is 372rwkw (to be exact by the theory).

These motors should be throwing pistons!!!

300rwkw on stockers

http://www.skylinesaustralia.com/forums/in...st&id=10930

275rwkw on stockers

http://www.skylinesaustralia.com/forums/in...t&p=1854575

305rwkw on stockers

http://www.skylinesaustralia.com/forums/in...t&p=1934095

280rwkw on stockers

http://www.skylinesaustralia.com/forums/in...t&p=2903298

310rwkw on stockers

http://www.skylinesaustralia.com/forums/in...t&p=2920655

I give up. Your right.