Theoritical power from injectors

[bbaacchhyy]

Hiya all,

I have been offered some 550cc injectors from a fellow Supra owner that wants to concentrate on his turbo gas setup.

They have had only 2 tankfuls of petrol through them, and there is a thought that one of them leaned out for a reason (unknown yet) during some tuning which led to the death of a N/A 7M that was turboed at about 15psi.

They are apparently ND's and he wants $300 for them. The plan is to eventually use them on the 7M to get to my figure of between 200 and 250 rwkW.

According to the RC injector site, 550's are required to get to 250rwkW at 80% duty cycle and 45psi pressure - does this sound right ?

And secondly, what sort of issue would cause an injector to go lean (presuming all things being equal and OK) during a power run ?

Is the price of $300 a good deal ? i.e. too good a deal to let go ?

Cheers

Michael B

[JustCallMeOrlando]

IIRC, Glen was using 550cc injectors to make his 340rwkw+. I would've thought the 430cc 7MGTE injectors would be capable of the power level you're after. I hope so anyway, because I have a set of them now

[The Witzl]

$300 is a good deal mate - grab em.

Yes, 550cc/min x 6 cylinder is capable of that power JCMF... with a rising rate FPR and around 90% d.c.

[bbaacchhyy]

Cheers for that.

Will have to see how I can stretch the budget around that.

Cheers

Michael B

[bbaacchhyy]

Snaffled them for even less !!!



Yet another thing to be installed on the other engine .........

[CrUZida]

550cc/5 = 110hp per injector
*.85 duty cylce = 93.5hp per injector
*6 cyls = 550hp+

550hp at fly is 330+rwkw

Even a set of 440's can do 250rwkw.

And that is not taking the increase in fuel pressure into account.

[JustCallMeOrlando]

Isn't Josh using 7MGTE injectors for his 1GGTE?

[CrUZida]

Pretty sure yes.

[bbaacchhyy]

550cc/5 = 110hp per injector
*.85 duty cylce = 93.5hp per injector
*6 cyls = 550hp+

550hp at fly is 330+rwkw

Even a set of 440's can do 250rwkw.

And that is not taking the increase in fuel pressure into account.

Thanks Andrew, just the confirmation that I was after. I was pretty sure that the 440's would be OK, but the big advantage 9apart from the cost) is that the MAFT can cope with different injector sizes without any issue.

What do a good set of 440's go for these days ?

Cheers

Michael B

[JustCallMeOrlando]

Depends where you look, they usually go for around $250 here, whereas I bought a set from the US for AU$91 including postage.

[bbaacchhyy]

Depends where you look, they usually go for around $250 here, whereas I bought a set from the US for AU$91 including postage.

Got them (the 550's) for AUS $250, but the [price you got the 440's for was very good, especuially the way some yanks work out their postage rates !!!

Cheers

Michael B

[JustCallMeOrlando]

The USPS kicks ass when it comes to getting stuff from the US. The dude was really good too, took a week and one day from buying them to having them in my hand.

[ed]

my 440's cost me $180 off toymods with plugs and leads

also - i wouldnt really use the fuel pressure reg as a way of squeezing more fuel out of the injector: the velocity flow within the injector needs to be considered, just get the correctly sized ones...

[The Witzl]

also - i wouldnt really use the fuel pressure reg as a way of squeezing more fuel out of the injector: the velocity flow within the injector needs to be considered, just get the correctly sized ones...

that is such an "all-motor" spaz's comment

This is my personal understanding of the use of adjustable/rising rate FPRs on Turbo cars....

The idea of an adjustable or rising rate FPR is more to maintain that velocity you are referring to. When you are moving close to 2 litres per minute with intake pressures above 2 bar, spray and flow velocity go right to p00town - so to get a good spray and fuel atomisation in such harsh conditions you put a little more pressure behind the injector and run it at a lower duty cycle....

... i havent come across people (other than retards) maxing out their injectors and then using an adjustable FPR to go further.

[ed]

oh yeah, totally agree with the concept of using rising rate reg to equalise pressure on the fuel rail with increasing pressure in the intake - thus providing the same differential pressure, and maintaining the injectors flow rate and internal velocities...

cranking up the rail pressure to 45, 50, 60 psi simply to increase fuel delivery as some yankee's commonly do is just farkin stupid though