Fuel System
The SyTy's fuel system has several weak points as it came from the factory. The first thing that everybody should do, even if you don't plan to modify you your truck, is to replace the fuel pump. We have an in-tank fuel pump and there is quite popular upgrade available from
Ron Gregory to replace it. It's a direct drop in made by Walbro in three version. I'd suggest to use the largest one, high pressure, 255 l/hr pump. It's a good insurance for a stock truck and could support up to 600HP in a modified one.
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A few remark regarding the pump replacement. There are two ways to do it on a Sy, and only one on a Ty. On a Sy you can drop the tank or remove the bed, while on a Ty you have no options other then drop the tank. There is a piece connected to the pump assembly called the pulsator.
It's main function is to filter out some vibration coming from the engine via the fuel rail. It's tend
to leak why you can find a rubber hose in the Walbro package to replace this pulsator. Also my fuel pum
p became much more quite after removing the pulsator.
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Beside the fuel pump the next most popular upgrade is to replace the fuel pressure regulator. The stock unit is a non adjustable unit made by Bosch. It's sitting on the passenger side's rear corner of the fuel rail. You want to replace it with an adjustable unit. There are quite a few manufacturer like KB, ATR, Connley etc. These are typically repairable, billet units. AFAIK we are using the same FPR as the mighty GN's and Turbo Regals so you can easily find one.
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If you want to enjoy the versatility which you just gained with the AFPR installation, you will need to install some kind of fuel pressure gauge. There are mechanical or electronic units. You can quite easily connect a mechanical one to the test port on the fuel rail (after removing the valve from the port), but you can't, and shouldn't put a such a gauge in the cab. So, if you want an in-cab FP gauge you can use an insulator with the mechanical gauges or you can use the electronic ones. You can hear a lot of bad things about the insulators so I'd say go with the electronic gauges.
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To set your base fuel pressure with the adjustable unit, you have to disconnect and plug in the vacuum line which goes to the FPR. You can do this while the engine at idle. The base fuel pressure depends on a lot of things, but you can use start from ~42 PSI with a stock chip and from ~50 PSI on the 3 bar chips.
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The next components when we are talking about fuel system upgrade are the injectors. We are using 28 lb/hr injectors. If you want to change these, you have to make changes to your engine management system too. These injectors are high impedance ones, so if you want to stay with this type of injectors and the stock ECM, the top is 50 lb/hr. There are KB and ATR selling 36 lb/hr injectors with chips for them. I wouldn't suggest them since their chips are trash. So the next step beside doing your own chip stuff is to use Brian Green's 50's chips. These are multichips, similar to the Ultimate's. More information on them on my
engine management page.
If you need more than that, you have to use low impedance injectors with some kind of 3rd party engine management system.
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An other cheap modification is the hot-wiring of the fuel pump. With the stock system
the fuel pump suffers a serious voltage drop especially under WOT conditions. Lower voltage
means, less flow which could result in lean mixture, which is bad. The difference could be as much as 15%
if you compare the flow rates on 12V vs 13.5V. To correct this you can
fabricate your own hot-wire kit, or you can buy one.
Racetronix
offers a very nice harness, which I recommend to use.
It's completely a P&P unit, comes with top quality parts and their service is also real good. It's using a 10 gauge
wire which is much larger than the stock one. It's a cheap insurance. Don't expect any significant change performance wise from this kit. However
you might be able to stretch the limit of your current fuel system a bit more with this harness.
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These are the basic things. Beyond this comes the wild stuff. With an 'all out effort' build up you probably have to use billet rails and fuel cells, but that's not my leag so far.
Finally pls remmeber to replace you fuel filter regurarly.
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