Bulkhead connectors and where to branch the wiring harness

Hello All,

I'm working through installing a Life Racing F88 in my 1998 TVR Cerbera, the engine is unusual, a flat plane crank V8 running with individual throttle bodies. It has dual lambda sensors and dual throttle pots, one per bank in each case. The point of the move is to change from the batch fired injection of the original ECU to a fully sequential setup. In a second step I'll make use of the traction control strategies the F88 has to offer, the standard MBE system having none. The wiring currently goes from the ECU in the passenger footwell through a single grommet and into engine bay, this leaks and like quite a few things on the car could have been done a lot better.

The space through which the cables go is quite small, so I'm thinking I would introduce automotive connectors to both provide to neatly handle the number of pins from the ECU and also to provide a waterproof joint. The ECU would remain in the footwell tucked out of the way, so I then have a choice of where the loom is spliced to provide the appropriate number of 5v feeds and sensor grounds. I can either do the splicing within the harness section in the car, in say the ECU connector as mentioned on the course, or I could do the splicing in the harness in the engine bay. There would be fewer pins into the engine bay, which may help in terms of packaging, however on the other side of it perhaps the way to go is to twist the wires running out to each sensor from the bulk head connector for noise reduction.

From listening to Zac and watching the course material its clear to me that it's not a trivial process to redo parts of the loom, it's a job you only want to do once. So what approach is generally taken and why is this.

Many thanks,

Steve

G'day Steve.

In your application, I think I'd do my splicing on the engine bay side of the harness, right behind the bulkhead connector on that side, as it does sound like it's going to be much easier, and keep the interior side of the harness smaller. This will also have the benefit of reducing the number of pins required on your bulkhead connector.

It's a case-by-case determining where this should be done. From memory the F88 has a few 5v outputs? Are there any sensors you'll be interfacing to on the interior of the vehicle, or at the rear, where the wiring wont pass through the bulkhead? If there are, I'd supply those with their own dedicated sensor 5v and ground pair.

When it comes time to configure and tune, we've got a worked example on a Syvecs ECU that you might find useful, as they share a lot of the hardware with the Life Racing ECU's, and the software is also quite similar.

Hey Zac,

Thanks very much for your advice, really helpful! Re. the 5v feeds, yes there are only two of them and iirc they support an output of only 150mA (not sure if this is each or cumulatively). I expect this is fine for their typical usage but will be checking for it my application. Within the car I'm thinking of a steering angle sensor in the future, so it sounds like I should make provision for this upfront, even if I don't do it in the first pass. In a similar way I presume I should also think about CAN wiring for additional units such as their PDU 10/16 should I need any extra inputs and their GPS/Accelerometer which I gather is used in some of the traction strategies.

Thanks,

Steve