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Fuel injector upgrades

Posted: Sun Dec 23, 2007 4:18 pm
by Rmachines
Hi Does any one know if you can take injectors off another car to fit on the AEX engine? and if they are slightly larger capacity would it effect a stock engine atall?

This is all part of my modifiaction project but i dont know much about injector upgrades so would like to be filled in :)

If i was to get some slightly larger injectors, would fuel pressure etc need changing? How would it effect the engine? and would there be any point...?

Could i do a straight swap without effecting the ECU?

Is there any other vehicals they could be taken off? Would fitting 1600 to a 1400 make any diffrence?

Any advice would be very usefull, thanks :)

Posted: Sun Dec 23, 2007 5:00 pm
by BIG4244
Before starting my current engine mod/change, i got some 20v non turbo injectors for my AEX but they were to big, i also tried running my AEX engine on AEE injectors amd inlet manifold (AEE manifold is slightly different to the AEX) but it wouldnt run properly. I think up rating the injectors on there own would have not much effect, you only realy need more fuel wqhen your getting more air into the cylinders e.g. turbo/supercharger

Posted: Sun Dec 23, 2007 5:04 pm
by JarnoVWPolo6N
BIG4244 wrote: I think up rating the injectors on there own would have not much effect, you only realy need more fuel wqhen your getting more air into the cylinders e.g. turbo/supercharger
Bingo! :wink: Just putting in bigger capacity injectors doesn't have any effect, well it does have one effect, it f*cks up the idle run and acceleration of the car, since it get's too much fuel compered to the amount of air it sucks in. Slightly increasing your fuelpressure has more effect, unless your going turbo/super-charged

Re: Fuel injector upgrades

Posted: Sun Dec 23, 2007 7:34 pm
by bstardchild
Rmachines wrote:Hi Does any one know if you can take injectors off another car to fit on the AEX engine? and if they are slightly larger capacity would it effect a stock engine atall?

This is all part of my modifiaction project but i dont know much about injector upgrades so would like to be filled in :)

If i was to get some slightly larger injectors, would fuel pressure etc need changing? How would it effect the engine? and would there be any point...?

Could i do a straight swap without effecting the ECU?

Is there any other vehicals they could be taken off? Would fitting 1600 to a 1400 make any diffrence?

Any advice would be very usefull, thanks :)
OK as you said you don't know that much about injector upgrades so here are my answers to what will happen and why

If you fit larger capacity injectors on their own the net result will be you will over fuel the car from tickover right up to the red line without gaining any extra performance

The ECU controls the injector duration based on parameters in the "chip" it can't tell what injector size is being used it just uses the setting from a base map

If you fit bigger injectors you need to remap the base map to lower the injector duration so that the same amount of fuel is added as before a huge amount of effort for no gain at all - the injectors are sized to be running within their range (ie not 100% duty cycle which is bad news to run injectors at 100% duty cycle at peak rpm)

I've looked at the AEX engine in terms of how to get more power out of it and it's got tiny ports so would require lots of porting work (expensive) for only a small gain.

Best way to get more power is heart transplant ie 1.6 8V or 1.4 16V and to be honest the best way is to sell the car and buy one with a bigger or better engine as it will be easier and cheaper insurance wise in the long run.

The AEX lump is a nice little engine but as a base for performance upgrades it's not a good base

Posted: Mon Dec 24, 2007 11:54 am
by Rmachines
Hi, thanks for the advice there, its good to gain some knowledge about the injectors etc..

I already have my GT-Four as a performance car, which is why I would rather play with my 1.4L engine to try to milk it for more power, rather than stick another lump in it. I’m not after the peek power so much, I’m more curious as to how much I can squeeze out of a 1.4L engine without using forced air. I see it as a bit of a project and a chance to fiddle. I’m trying to get as much knowledge of different methods of modification which is applicable to the 8V engines as well so I can seriously think of what I’m gunna do.

If it wasn’t for my other car being so thirsty I would have certainly considered a larger engine, I have spent most my life working with ford CVH and Jap motors so never looked into the VW engines much but now I have one I wanna play :D

So….. From what I have got so far, the best thing to do is use a Mk2 loom, Fit a ported camed 1.6 AEE Head and stick on bike carbs. ? ?