DIY Fuel injection thread.

[Roman]

Another thing, and you'll have to excuse my hypocrisy because I've currently got a big lead acid battery sitting behind the passenger seat. Ha. 

But, when I had the battery mounted in the boot of the carina. 

When I switched to a lithium battery, which happily can crank over the V6. 
The battery weighed less than just the cable that I had removed to remote mount the battery. 

My lithium battery broke the terminal part from me doing stupid things with it, but plan is to buy another one and put it back in the bay. As it makes everything so much simpler, and its a lot lighter. 

Not that I'm guessing your tooooo fussed about weight given 4WD stuff added etc. 
But its also incredibly simpler with a lot fewer points of failure. 

Appreciate if you want the look of a clean engine bay though and want the battery out of there.

[shrike]

32 minutes ago, Roman said:

Main thing about voltage fluctuating is to make sure that your injectors and coilpacks are getting power from same-ish supply as the ECU. 

So if the ECU dips to 12.0v, your injectors are also seeing 12.0v so your deadtimes are correct. and to a lesser extent dwell time for coilpacks.

The NEXUS will be providing the power to the injectors and coils (1 and 2) 3 and 4 will run the fuel pumps

Factory fuse box will manage the Rad fan and anything else that needs power the NEXUS can't handle

Thanks everyone that helps

[mjrstar]

49 minutes ago, Roman said:

When I switched to a lithium battery...... put it back in the bay, 

 As it makes everything so much simpler, and its a lot lighter. 
 

I just came here to say this^^ If it's not a daily driver , I have one car with a battery mounted in the boot (garbage) and one car with it where it belongs in the engine bay (not garbage)

So long as there is no parasitic discharge from an alarm or whatever, these things last 3-6 months plus without a charge, yes they are a bit expensive, but worth it in my opinion.

In fact it's about the only "flash" thing in my racecar.

[shrike]

58 minutes ago, Roman said:

Another thing, and you'll have to excuse my hypocrisy because I've currently got a big lead acid battery sitting behind the passenger seat. Ha. 

But, when I had the battery mounted in the boot of the carina. 

When I switched to a lithium battery, which happily can crank over the V6. 
The battery weighed less than just the cable that I had removed to remote mount the battery. 

My lithium battery broke the terminal part from me doing stupid things with it, but plan is to buy another one and put it back in the bay. As it makes everything so much simpler, and its a lot lighter. 

Not that I'm guessing your tooooo fussed about weight given 4WD stuff added etc. 
But its also incredibly simpler with a lot fewer points of failure. 

Appreciate if you want the look of a clean engine bay though and want the battery out of there.

I am actually trying to save weight were I can, and long term ill be swapping anything I can to composite panels (hopefully carbon fibre) 

But atm ill compensate with more boost once I turbo it

Cage and subframes are/will be Chomoly

As I added more weight to the rear end im keen to move the battery more central, and clean bay/space is at a premium, though looking at the below pic of a factory bay I stole from the internet.

I might be able to put it a small battery where the Powersteering fluid tank is, especially if I reduce the size of the washer tank (or remove it)

Engine and gearbox oil coolers will be in front of the drivers guard or somewhere in that location.

Haven't decided what side ill put the half rad yet but most likely itll be on the Passenger side

Remind me which lithium battery you use? Ill be keen to get one as I currently don't have a battery for this car

Factory battery spot is where the air intake will be going (I actually had the battery tray removed as well)

 

[Roman]

There's an old story, perhaps it's a wive's tale, I dont even know what sort of era it's from.
But anyway.
Someone developed some aero doodads for the front of the car or something, and the car was going really fast.
When they bought the car into the pits, the crew would quickly go throw a blanket over the rear of the car. 
Everyone was so fixated with trying to see what was under the blanket, that no one bothered to see what was hiding in plain sight.
What I'm trying to say is, if you make something in the engine bay out of carbon fiber, and then draw some titties on it.
No one's going to look anywhere else in your engine bay

[mjrstar]

I run a shorai, in my car it's situated under where your wiper motor is.

 

Ignore the birds nest that's an optional extra you probably don't want.

[Roman]

I have / had an Earth-X battery. Chose that brand because it had extra protections in it for short circuiting / overcharging / etc compared to some other options. 

But that was a while ago, they might be all same same now. 

[mjrstar]

The reason I run a shorai is a guy at work was throwing it out because it was "no good" also the battery he replaced it with was also no good so that piqued my interest. There are probably better /cheaper options than that.

I bought a proper shorai battery management charger thing that plugs into the port which I have never needed.

[shrike]

35 minutes ago, mjrstar said:

I run a shorai, in my car it's situated under where your wiper motor is.

 

Ignore the birds nest that's an optional extra you probably don't want.

Ill have a turbo and exhaust pretty near my wiper motor area long term not sure I want a battery that close even with heat shielding, but does help with sizing and location placement ideas

[GARDRB]

I'd run the battery in the passenger's footwell or behind the passenger seat. I am a big believer in keeping it close to keep it simple and not need as much heavy wire everywhere.

In my friend's SSS Sentra racecar, he wanted to put the battery way in the back until I pointed out that mounting a lightweight battery on its side in the factory position meant he didn't need a huge amount of cable everywhere. Everything that needs battery power is in or around the engine bay. If you're running dual 15" subs each with its own dedicated amp, then go hard and put your battery in the back of the car. But it doesn't make sense to lose all that power to voltage drop getting the power back to the battery, and then using the power in the front of the car.

It also means that you can run a smaller battery cable and terminals, which all costs extra the bigger you have it, plus you need annoyingly large cutters and crimpers and large battery cable is a ballache to work with. Battery terminals are also a great distribution block. You can bolt all your extra cable runs to the battery terminal and then you don't have to buy an additional distribution block.

These are amazing. E46 engine bay positive terminal. They are like $10 at pick a part and give you a nice isolated engine bay terminal if you need one.



 

[Dudley]

Stupid jawsh

[xsspeed]

Is anyone using HP tuners on anything modernish?

[shrike]

Wasn't sure what thread to ask this on but @kpr the VVTI pully from the JZ family was there a reason that worked better then say the Altezza 3sge VVTI or the 1GFE VVTI pulley?

Or was it more about part availability? 

[kpr]

jz pulley fairly well priced new, well used to be at least.  compared to the others.   apparently the beams ones  have a spring inside that makes it a fun time to put back together.   jz one is super basic, easy to pull apart.  
But if i was to do it again i would probably look into other options.  the jz one is slower to operate than the newer designs.  Its not terrible and a non issue in most cases.  but can lag behind if go through the revs super fast. 

[yoeddynz]

On 19/05/2025 at 12:01, mjrstar said:

 

Is that a Mugen nest? 

[yoeddynz]

Just for the record. I put the battery in the front of my Imp because it's about the weight of one standard bag of 'handling improver' concrete. 

[mjrstar]

43 minutes ago, yoeddynz said:

Is that a Mugen nest? 

Could be, whatever it was it worked fast, wasn't there the night before and had appeared by the morning. Plus the car was in tow back from an event in taranaki for a portion of that time.