When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Partial assembly with printed parts. As soon as all the recent stuff comes out of the printer, its onto a car for final firewall clearance testing and then the POs go in for throttle components.
Here are some more photos with the mockup parts on the assembly so far. All the printed plastic parts will eventually become machined metal bits. Test fit, revise, test fit, revise..... its how you get a perfect fit the first time.
The new billet fuel rails just came back from the anodizer today. There are several design features to lower the weight and thermal mass, but also improve access to the manifold mounting hardware. Ports for fuel dampers between each "pair" of injectors were added to decrease the nominal diameter to a -6 size for further reduction of fluid heat transfer.
What are the odds that a VW Bosch 4 bar FPR will fit in the spot of one of your dampers?
Zero chance - the "socket" is a completely different shape. I have modeled rails and regulator housings to use the Bosch insert, and have those designs on the shelf. The bosh regulators are great, and I would have used one if they would flow enough return for this application. All the factory Bosch non-motorsport regulators are designed for 220lph of return flow through the metering orifice. Beyond that, they will not behave linearly, and you will need to account for that with an active feedback loop using a fuel pressure transducer and correction table.
I am using a 350lph pump. so needed something with a larger orifice to account for the large amount of return flow at idle, cruise, and decel periods. The regulator I have selected can support up to 500lph of return before linearity is effected. It is always a good idea to use a FP transducer and correction/failsafe table, but its sure is a lot better when you are working from a stable linear output to start with.
One way around the issue is using a PWM controller for the pump, so it always maintains a relation in which the excess capacity beyond the need of the injectors is under the 220lph threshold. It is something I considered myself, but thought better about it for troubleshooting purposes for others downstream.
Wow, that makes me want to buy a kit and go get the car later.....
I don't have the heart/soul to adopt & re-sort another 928 though. I look forward to living vicariously for those that can/do, its way cheaper and somewhat less frustrating.
01-17-2019, 03:00 PM
