Bypass the stepper?

[poorpeet]

I went down to Fernies last week & listened to a
Griff with a sleeved exhaust. It sounded really nice but if I do the mod I want to be able to stop the thing going to high revs on start up before the stepper motor adjusts the tickover. As I understand it the stepper is there to make sure things like the air con & pas don't drag the revs down when they are on?
As my old beast does not have any of these can I just clamp the bypass hose to remove the stepper from the process or will this cause problems with the ecu trying to adjust the revs?

Pete

[GreenV8S]

In principle I don't see why not. The engine needs more throttle to idle when it's cold so without the stepper you'll find it idles faster when it's hot, and may need a bit of throttle to keep it running for the first couple of minutes on really cold days. A top tip from Joolz is to put a restrictor in line with the bypass hose to limit the revs that the stepper can give you, that might be a better solution for you.

[poorpeet]

Hmm? Thanks, that sounds like a cunning plan. Any idea how much of a restriction?

[GreenV8S]

You can get a feel for it by simply squashing the hose flat with the engine running and seeing how far you can go before the revs start to drop. You could even use an external adjustable clamp to make that a permanent solution - hose clamps are readily available.

[spend]

Make your own clamp with 2 brackets bolted at each end to squeeze the pipe & adjust to suit ?

Dave

[trackcar]

If you want something adjustable as a restrictor get a radiator bleed valve and plumb it inline in the pipe to the stepper motor .. wind the adjuster in / out until you get the desired start up revs. Some of the bleed valves adjusters are a loose fit on their threads so some thread tape around it will help, or count the number of turns you've got it set to and thread lock it in place afterwards

[poorpeet]

Thanks. I'll have a fiddle

[Overhere]

Was wondering if one of you could tell me where this hose is? I'm thinking of several options to my exaust to do this winter, decat, sleeve, sports exaust, but I live in a quiet cultisac, shhhh, don't want to drive them MAD!

Thanks

[spend]

Look behind (to rear of car) the throttle linkeage

Dave

[im]

spend said:

Look behind (to rear of car) the throttle linkeage

Dave

Anybody got a picture?