SWIFTY

hi i have a 2wd cosworth on a g reg and i was just wondering if it would have a rev limiter??? as the rev counter has stoped workin an i carnt get the dam thing to work. i dont want to give it to much if it hasnt cause i dont want to blow it up.

thanks.

Turbo Zetec

iTrader: (1)

change gear when you start feeling the power drop off! surely you don't need to look at the rev counter every time you're going to change gear?

cosrep

There is a rev limiting routine in the ecu software that will cut the spark if the preset rpm limit is reached.

SWIFTY

no i dont need to look but it seems to have power all the way up the rev range (well as far as i want to push it with out knowing if it has a limter) would like to no if it would hit a limiter or keep going untill it drops of the cam or off boost.

oldford

If you are using a standard and original Weber Marelli Ecu then it does have a rev limiter.
In fact it is a two stage limiter which works by cutting the fuel.
On the first soft limit (6800 rpm) every other injection is not done, when it reaches the second limiter (7000 rpm) all fuel injection is stopped as a hard limit.

cosrep

Really..?? I thought it was the ignition that was cut, F**K cutting fuel at full boost at 6800+rpm that can't be healthy for the engine

oldford

Rev limiters on ecu's are achieved by cutting fuel or cutting BOTH fuel and ignitiion.
This is done to prevent unburnt fuel getting into the exhaust. The unburnt fuel would ignite the moment fuel and ignition are activated again when the rpm's drop, causing explosions, excessive heat and large flames in the exhaust. Imagine what this would do to a catalyst.

A rev limiter also works in cooperation with the boost control software. The ecu will lower the boost just before hitting the rev limiter. So, you are never at full boost when the rev limiter kicks in with a standard ecu. Don't know what all tuners (professional and otherwise) have done with these settings.

tabetha

As said two stage limiter on cossies, often raised on chips though to higher revs, mine is 7300, some clever ones merely retard the timing to drop the torque so speed goes down.
tabetha

R5FORD

iTrader: (1)

mine revs happily to the limiter..dosent drop off or anything

Norwegian Wolf

No limiter on my chip..
Runs with mech. lifters thou..
Revs nicely and powerful to easy 7500

tabetha

With me new ecu the limiter is going to be set at around 8200, as will suit different inlet cam then.
tabetha