Resistor pack for low impedance injectors on 1JZ?

[Jabtronic]

Just wondering if anybody could give more info on resistor packs needed for low-impedance injectors on a 1JZ.

My mate Jake just bought some drop-in 550cc USDM 2JZ injectors (apparently.. except they're dark red instead of purple though so could just be off the shelf 550cc Denso's.. will find out soon) and so we will need to fit a resistor pack if they are indeed low-impedance.

I've been searching around on other forums, and aside from using the obvious (USDM 2JZ resistor pack), some people are saying that we could use a 7MGTE one, or we could make our own..

So does anybody have better info? I've been given this diagram



And here's the info I found about making your own resistor pack, we'd probably go this route as it will be cheapest but will have to check where to buy the resistors from.

http://www.supraforums.com.au/forum/...5&postcount=17

You need to buy six individual resistors that have the same specs. Those specs are available at this website:http://www.e-sonic.com/acc/products....command=detail

Renfrew axial wirebound resistor, type PW10.
10 watts, 6R8 resistance.

If you cannot source them in Australia I will send them to you. They are about $2 each.

Here is how to assemble them.
There is one common power wire in your car that comes into the SFI Resistor Pack. This wire is connected to one end of all six resistors. (Each resistor has a wire coming out of each end of it.) The resistors are parallel to each other like six lanes of traffic. The other end of each resistor connects to the wire going to each individual fuel injector.
So you can see how the car's 12V power is put through a single resistor for each fuel injector. Common power supply but individual wires to each injector after being lowered in resistance to what these 540cc injectors require to run properly. In case you are wondering, the other wire going to the injectors goes to the ECU to ground the injector. Toyota uses a pull-to-ground method of controlling fuel injectors with the ECU.

Any further info would be appreciated Anybody else running 2JZ 550cc injectors on their 1JZ? Would like to see pics of how it's wired up.

[jzk25]

I have used GTR and old R30 skyline resistors on 2JZ's as well as what is described in the email. They are a common resistor to get from an electronics shop I think(I got them from a mate who is in the trade). The GTR resistor does look a lot better though, the others look seriously home made.
2JZ's are sequential though, by that diagram 1JZ's are grouped so you would only need a 3 channell resistor not 6. You can get new GTR resistors from just jap, the individual generic resistors are the cheapest by far though.

[wilbo666]

RS electronics have the little resistors you want

RS have 'trade counters' where you can go and get them from...

$2.49+ ea, come in a wide range of values (10watt)

Edit: I'd prbly go with 25W ones tho, $3.59ea+... but then again I'd prbly use a resistor pack off something else as has already been suggestd!

e.g.


http://australia.rs-online.com/web/s...duct&R=0160714


Cheers
Wilbo

[CrUZida]

That drawing is backwards too.

[CrUZida]

It should read

[Jabtronic]

Cheers for the info.

Went and bought some PW10 6R8 resistance resistors today from Prime Electronics for 95c each, just need figure our how to mount them...
They look similar to the top one



I'd have to hot glue them to a circuit board or something like that.

I'm thinking it might be easier to get the Arcol ones and then they can be pop-riveted onto a piece of aluminum etc.

[CrUZida]

Dude, I dont know where that other guy got 6.8 ohms from. And I don't know why he says you need 6.

Stock high impedance injectors are normally 13.8ohms, where as low impedance ones are 2.7 ohms.

Therefore if you are using 6 resistors, you'll need 11.1 ohm resistors.

If you are using 3 resistors (much simpler), then you'll need 5.5 ohm resistors.

I'd also get a minimum of 20w resistors. 10w seems too small on paper, and these things are going to get fucking hot without a decent heatsink.

With the setup you've got, you'll be putting ~50% higher current through the ecu injector drivers than stock. I'm not sure what the ecu's limits are before you start burning things, but a 50% protection factor would be unexpected to say the least.

To sum it up, get a 7MGTE resistor pack.

[Jabtronic]

Ah ok, thanks for clearing it up.

We'll probably still go with resistors though, I'll just take these ones back and get the right ones.
7MGTE resistor packs seem to be pretty hard to find (got a WTB thread here) and the 2JZ and GTR packs are pretty expensive ($100-$200 2nd hand?)

[Jabtronic]

Bump.

I had bought some individual resistors (in the previous post) but then decided to take em back as I couldn't think of a way to make the resistor pack without it looking messy

It seems that z20 Soarers (which the 1JZ is in) have a resistor pack. So I'd just like to confirm if I can use a 1GGTE resistor pack? I havn't had a chance to look at one yet. I'm also wondering what would be the neatest way to wire it up?

[DrNick]

Having recently constructed a resistor pack for my 2JZGE to run the low impedance Denso 440cc injectors I can probably help you out.

First off - the stock 7MGTE resistor pack was a huge disappointment, it seemed poorly constructed and the impedance was way too low for my needs. I know there are people using that same pack with on the 2JZGE but it would draw so much extra current that I would consider it a bit of a time bomb.

Now, I seriously over engineered my resistor pack but you should be able to get the idea With regard to the wattage of the resistors, you can consider that a measure of their ability to dissipate heat. Putting a big heatsink on a resistor increases its usable wattage, similarly putting the resistor in a hot place (such as a hot engine bay) decreases its usable wattage.

If you look at data sheets for the resistors (and I do love reading these things at work), many 25W resistors are actually only rated at 10W @ 70C. Since the price difference was minor, I went for 50W resistors. And 6 of them at that.

Having developed a fondness for Vishay Siliconix semiconductors at work (yes I am one of those nerdy types) I went for the Vishay resistors.

Farnell (online) can supply these and many more

This is what they look like



I sourced a stainless steel casing from jaycar electronics that could house six of these suckers with plenty of room for air to flow between them



Don't use glue or tape or anything like that to hold something like this together. This is all held together with bolts. I drilled out bolt mountings into the casing so that these could all be bolted together into the frame. The contact area between the bottom resistor and the casing has a patch of thermal tape to aid in the heat transfer.

This is what it looks like with all the wires



I don't have a pic of it in its final position, but you get the general idea from this pic of where I mounted it. I drilled and tapped an M6 hole and secured it with a decent bolt. I've got a few more random pics lying around, I wasnt sure which were the best ones to post so if you need more details just give me a shout and I'll put some more up.

[Jabtronic]

Cheers heaps for that, very informative and certainly gives me a better idea of how to make the resistor pack.

+rep

[renxun]

so now who had the injectors ran on the 10w home made resistor pack? i seems cant drive mine yet.
felt it had not enough current to crack my injector open when operating them wid the stock 45psi static fuel pressure.. when the fuel pressure was put down low to 1bar static it will tick and idle nicely. whenever i bump up the pressure the afr go leaner and leaner till it dies off... replaced back the stock injectors. it idles perfectly and the afr does go rich when i bump up the static fuel pressure...

really had a great headache try to sort this thing up

[Hengsta]

Bumping this back up.

I think i have problems with my resistor packs or injectors!!

Do the resistor packs goes on to 12v? or the ground side of the injector wiring?

I have suspicion that my resistor pack is not doing its job or i have wired them wrong due too trying to start the car when warmed up and car won't start!?!?!?

[thechuckster]

Should be:
Ign-switched 12V -> Resistor pack -> injectors -> ECU -> Ground

Have encountered one vehicle where an arse-hat masquerading as an auto-sparkie had 12V Batt power hooked up to the Injectors and Fuel-pump switch in the AFM.


edit: I recall encountering resistor packs from Crowns and Cressidas (not 7M, older motors like 5MGE) that had 6 outlets from the pack.

[skin]

Having read all this the only thing I'm not 100% clear on is something cruzida mentioned about what ohm resistor to choose

Now I can see why if you use six individual resistors each one has to have a value of around 11 ohm as it bring the total resistance of each injector up around standard 13 ish ohms

But I'd you are to run 3 resistors I thought the value of each would have to be double, say around 20 ohms not 5 like was mentioned?

Can someone set me straight please