Going single ...... on a shoe string!

[ozzie]

so what happend here then

[UltraFlynn]

I'm resurrecting this thread because it's exactly on-topic for what Cass is planning and I'd really be interested in knowing what would be required and how much they can be sourced for to do this.

[UltraFlynn]

Parts list:

1. Manifold
2. Turbo
3. Wastegate
4. IC Piping
5. Fuel Controller

Is it feasible to run a single on the standard j-spec fueling system?

[Martin F]

Originally Posted by Flynn

Is it feasible to run a single on the standard j-spec fueling system?

That's a very open ended question, as it depends on what turbo, what wastegate spring and how well the fuel components are performing relative to when they were new.

Theoretically (rule of thumb) the stock jap spec system could support up to about 450bhp, if all is running fine (pump, filter, injectors, fpr). However i'm always very nervous when people say they are going to fit x-turbo and keep the boost down because of the fuelling as red-mist can take over and before you know it a big bill can be on the way.

[UltraFlynn]

I agree. The temptation to push power levels are always going to be there. But if the car is running BPU ok and the turbos go pop then running a single at BPU power levels sounds like a sensible approach.

So lets talk specifics:

1/ What turbo?
2/ What wastegate? And what spring?
3/ How can you test the fuel system to identify weak components which need replacing.

400-450 sounds about right. I would imagine that everyday boost levels 400bhp would be sensible.

Personally I favour a cast manifold. They radiate less heat, don't suffer from the stresses of tubular and are more compact. For the price I think it's a better option to get one rather than a cheap tubular manifold it's probably crack.

[Cass]

Would keeping the restrictor ring in place prevent you red misting on boost the controler.
Or whats the story there?

[UltraFlynn]

I would imagine you would control boost using the wastegate spring and not a restrictor ring.

[Martin F]

Well .....

1/ What turbo? - Owners\Purchasers Choice as there are a few out there.
2/ What wastegate? And what spring? - Depends on turbo chosen, but a 0.7 - 0.8 bar is about the lowest spring available for most wastegates i believe.
3/ How can you test the fuel system to identify weak components which need replacing. - Check the fuel pressure under load is a rough test. However the best way would be to test the pump and fuel pressure regulator on a bench. Injectors could be sent for flow testing (but may as well have them cleaned at the time). The fuel filter could be replaced as its a service item anyway.

Cast manifolds certainly have their place and on a budget conversion are probably a wise choice. Just check the quality of casting and port matching.

[Martin F]

Originally Posted by Flynn

I would imagine you would control boost using the wastegate spring and not a restrictor ring.

The restrictor ring is only a cludge for the lack of wastegate performance in the stock J-Spec system once the CATs have been removed.

As you say, the wastegate spring should be used for controlling boost, however you probably want to supplement that with a boost controller at some point to give you more control and to stop the wastegate creeping open as boost rises.

[UltraFlynn]

Originally Posted by Martin F

Cast manifolds certainly have their place and on a budget conversion are probably a wise choice. Just check the quality of casting and port matching.

Induction Motorsports in the US do their own cast manifold and that proven up to 816rwhp. That for me says that you wouldn't choose a tubular manifold over a cast one for performance reasons. The shorter runners decrease spool times and I reckon it would be the right choice for a daily driver.