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The mkiv Supra Owners Club

550 injectors - Question


Dragonball

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How easy is it to set up the fueling on a J-spec with the bigger UK injectors and pump fitted? Can an A/F controller easily be set to do the job or does it require dynoing?

 

If it is a relatively easy job to set them up, then I'll look at the costs of parts here. if I can get them cheaper than the US (which I should be able to do I suspect) then I might be able to organise a group buy if there is enough interest.

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Does anybody know of any reason why a set of 550cc side fed high impedence injectors would work less efficiently than 550cc low impedence injectors with a resistor pack?

 

Obviously the J-spec is designed to run high impedence injectors, so fitting a set of high impedence injectors and a high flow fuel pump should work as well as upgrading to UK spec without the agro of fitting the resistor pack... I know you'll need some kind of A/F unit to sort out how much fuel and when etc.

 

Am I missing something? :conf:

 

 

 

 

ps. Excuse me if I've got this totally wrong, I normally fit car alarms, not fuel injection :rolleyes:

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I was discussing the injector issue with an ECU expert recently who asked the question "what do you do to modify the duration when fitting larger injectors?" Does anybody know the answer to this? I assume he's refering to the fact that bigger injectors with the same duration as standard injectors will over-fuel. Don't look at me, I'm a carb man!

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Things like the Apexi AFC. There's loads more variations but that's just the first one to come to mind as I've been reading up on how it works.

 

You generally use them to trim down the injectors opening duration at lower rpm where the fuelling was ok and let the duration get longer, (more fuel), as the revs climb, (or when needed).

 

Ian C did a very good detailed post recently on this subject. Sometime over the last couple of weeks I think...

 

 

 

Again, someone let me know if I've got this wrong:rolleyes:

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I think it be mentioned but you want side feeds as a direct replacement. There is no reason they won't work with a SAFC or similar. You also want to check the fitment as not many standard injectors will fit our stock rails.

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Too much hassle hooking up the resistor pack etc If you have high impedence injectors stick with it. I checked with a couple of tech guys they say there is no problem using the High Impedence injectors on our jap spec cars which came with the 440cc. There is a company called POWER of japan that sells high impedence injectors in 550cc 680cc and 720cc.:)

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Right, loads of questions...

 

1, Other than injectors, AFC or similar and fuel pump. What else is required? - (Parts only, I know I'll have to get someone that knows what they're doing to set it up)

 

2, Would you need a larger fuel rail for anything over 550's?

 

3, Is there anyone in the UK that sells these injectors? - Are they Nippo Denso products

 

3a, Are there any cars that anyone knows of that run high impedence side fed 550's as standard? - Lexus V8?

 

4, Has anybody gone down this road before, using high impedence injectors?

 

5, How many people on here are looking at upgrading fuel systems very soon? - I know Graham Rudd is looking into this now and obviously Paul E, (sorry for hi-jacking your thread Paul :) ), as Nic suggested, a group buy may be in order, then a group set up session :).

 

 

6, Nic have you heard of the company Randy mentioned 'Power'? Can you find out if prices are better over there for us?

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Do I sense a group buy coming on? :)

 

Yep, as Matt says I'm also looking at getting my fueling upgraded very shortly. I think I'll go for larger than 550's though, if I'm going to upgrade I figure I might as well future proof and make sure I only have to do it once.

 

I'd like to know what someone like CW's views are on the best upgrade path for fuelling. I pretty much want to get my car ready to accept a big single or the HKS twins. I'm also looking into aftermarket ECU's instead of buying a fuel computer.

 

Terry, have you gone down this route?

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I did think about it Graham but then got a standalone which will support either type of injector.

 

RC engineering can make up 680cc High Impedance injectors that will fit the rail, but they are not too good when it comes to responding to e-mails.

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Originally posted by Matt Harwood

I have to confess, I was looking at the 680's myself. Hence the querey of needing a larger fuel rail :) ... Help required...

 

You don't need a bigger fuel rail. The only reason for changing fuel rail is to get cheaper injectors but they will be top feed.

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Originally posted by Terry Saunders

I did think about it Graham but then got a standalone which will support either type of injector.

 

RC engineering can make up 680cc High Impedance injectors that will fit the rail, but they are not too good when it comes to responding to e-mails.

 

They took a month to reply to me regarding their injectors?:rolleyes: I think you guys would be better of using the 720cc injectors with a Apex S-AFC and a 255ltr walbro pump(I have one)! As this would take care of your single turbo upgrade!

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Originally posted by randy

 

a 255ltr walbro pump(I have one)! As this would take care of your single turbo upgrade!

 

I have two:p

 

One pump is no better than a stock UK pump. Be careful.

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Walbro do various pumps, but none that actually flows more than a UK Bosch pump( CW sells a bosch internal that will flow more). The only reason I used two Walbros is that they draw less amps than the UK so are easier on the stock wiring when running 2. They are also noticably louder than a UK pump. Randy's statement scares me a little. Yes you can run a single on one internal pump but not a big single & you would need to be very careful what boost pressures you run. I would also want a constant overview of the A/F's. Always go for a safe option.

 

Leon sells Walbro's

CW gets great prices on UK Bosch pumps.

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