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The mkiv Supra Owners Club

What size injectors should I get?


randy

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I am currently running 440cc injectors and need bigger say 550cc injectors as I am running pretty lean at specific RPMs on high boost.

What should I do? I plan to upgrade to a single turbo in about 6/8 months say like the greddy T78 turbo. But I don't want to buy the 550's for the stock turbos and then again have to buy the 720cc to take care of the single. What injectors should I get? If I get the big injectors will it be OK to run with the stock turbos? Will I be able to control the fuel flow with S-AFC? Will the stock FPR be able to control fuel?

:conf:

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From what I've read you'll need twin in-tank pumps to supply fuel for a T78. A lot of the american tuning co's have fuel kits, which include everything you need for this sort of upgrade - injectors, fuel rail, lines, regulator, pumps, and all the seals and fixings etc. I have heard good things about PHR and Garage Advance, but do some research and shop around!

 

This would be the route I would take if I was doing that sort of turbo upgrade.

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Thanks for your response! I will probably buy the PHR fuel kit or what titanmotorsports is selling. But what should I do about the immediate fuel requirement? For now can I just buy the 720cc injectors and use a S-AFC to control the fuel, as I want to give my stockers more fuel.

Also since I am running really high octane gas I may be making more power and this may also be a reason why I am running short of fuel.:)

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Guest Martin F
Originally posted by randy

For now can I just buy the 720cc injectors and use a S-AFC to control the fuel, as I want to give my stockers more fuel.

 

Can somebody explain to me what the point of this is on a std Jap spec pump ?

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You have an unhealthy obession with fuel, get the FMIC you want to use with the single before you invest in injectors.

 

You can't just solve det problem by just throwing fuel at it...it needs cooler air.

 

 

Originally posted by randy

Thanks for your response! I will probably buy the PHR fuel kit or what titanmotorsports is selling. But what should I do about the immediate fuel requirement? For now can I just buy the 720cc injectors and use a S-AFC to control the fuel, as I want to give my stockers more fuel.

Also since I am running really high octane gas I may be making more power and this may also be a reason why I am running short of fuel.:)

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I know! I know I have been on about fuel for a while this is only because I know I am running lean, but yes I will get a FMIC very soon! And Gavin this is not det caused due to intake charge being too high! Its just that I have sooo many things to buy I don't know what to buy first?:conf:

New Wheels and tires.

98 spec 320mm brakes 4 piston calipers

Fuel Pump

Injectors

FMIC

RMM carbon fibre wing.

Front bumper from Do luck

Single turbo

New sparco seats

etc...etc....:conf: Need lots of money:baa:

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Guest Terry S

Gavin is right you should get a FMIC first.

 

If you are going to get bigger injectors I have a new HKS fuel rail going cheap! Don't piss about with the 650's get the 680's they sell for the HKS rail & hey presto. Did you get a resistor pack??

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Guest Martin F
Originally posted by randy

I know! I know I have been on about fuel for a while this is only because I know I am running lean,

 

How exactly do you know you are running lean ?

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If you are going to get bigger injectors I have a new HKS fuel rail going cheap! Don't piss about with the 650's get the 680's they sell for the HKS rail & hey presto. Did you get a resistor pack??

 

Hi Terry, could you ping me privately about that HKS fuel rail? Let me know all the details, what injectors are required, and what sort of price you're looking for :)

 

Randy, if you are planning to go to a single turbo, I would not bother upgrading anything on the fuel system now - fuel components are very expensive, and you will have the problem of how to control the bigger injectors with your current setup. Just go easy on the boost until you're in a position to upgrade. Better to do everything properly when you're ready...

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Guest Terry S

Paul have sent a PM.

 

Randy, you will be able to control the injectors with a SAFC or similar. You need the resistor pack to run the lower impedence injectors though.

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Originally posted by Terry Saunders

Paul have sent a PM.

 

Randy, you will be able to control the injectors with a SAFC or similar. You need the resistor pack to run the lower impedence injectors though.

 

 

Terry,

 

I was thinking of buying the high impedence injectors sold by POWER japan. If I do buy them, I don't need the resistor pack and also the wiring up of this gives me the creeps!:eek:

Are there any problems associated with running the high impedance Vs the low? Need your advice!

Thanks:)

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Guest Terry S

Have you got a web link for POWER out of interest?

 

I don't think you'll have any problems, after all that's what Toyota put in as standard. I think maybe High impedence are more expensive so they go for the low impedence. Have a look at http://www.RCengineering.com for price comparisons. You will need the injectors to be side feed injectors, otherwise a new fuel rail will be required. The stock UK pump will be OK for now, but you will need to look at the fuel system once the power goes up.

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Originally posted by Terry Saunders

Have you got a web link for POWER out of interest?

 

I don't think you'll have any problems, after all that's what Toyota put in as standard. I think maybe High impedence are more expensive so they go for the low impedence.

 

Terry,

the high impedance are cheaper than the low?:conf: http://www.rceng.com/prices.htm

What is the technical difference and why do they use high or low?

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