[Chris Mackey]

Having decided to install a nitrous kit in Elsie, I learned today that there are devices to control the behavior of the kit, depending on the engine speed. You can set an engine speed window where the device will be on, say 3000 to 7800 rpm.

The idea is to not dump N20 into the engine when it is going slow, because it causes too much compression. On the other hand, hitting the rev limiter is a bad, bad idea since the Lotus ECU will discontinue fuel delivery to the motor...but supply spark. The nitrous kit will continue dumping fuel and N20. You get a very dangerous lean condition.

Google "RPM Activated Window Switch" if you want details.

Anyway, I need a source for the engine speed. Does anyone know of a place this is available in the engine bay?

 

[charliex]

you can pick up from the coil pack via an inductive pickup.

 

[Chris Mackey]

you can pick up from the coil pack via an inductive pickup.

This must be similar to the old school flashing light I used to time the motor in my '71 Firebird. Thanks, Charlie.

 

[GTsRasta]

I hope you read this thread: http://www.newcelica.org/forums/showthread.php?t=248998

Good luck!

 

[ZJChaser]

MSD inductive pickup. Tach Signal GMR Pickup, PN 8918 I use one for my data logger.

 

[Chris Mackey]

I hope you read this thread: http://www.newcelica.org/forums/showthread.php?t=248998

Good luck!

Thanks again.

He claims that this is "extremely" safe with a 50 shot NX kit:

02+ 2zzge ecu rpm window is 5800 to 7600

I'm sure it is safe. I'm going to be more aggressive. Jason certainly is, and has had no problems in the last 18 months.

MSD inductive pickup. Tach Signal GMR Pickup, PN 8918 I use one for my data logger.

Ah yes, perfect. $40 for this and about $95 for the window switch - seems pretty reasonable.

 

[GTsRasta]

Just to let you know, the 02 and 05 GTS ECU has the lowered rev limit. The 00-01, and 03-04 ECU's have the 8,400 rpm rev limit. Since you have the 8,400 rpm rev limit, you can squeeze out the extra 200 rpms no problem based on what he says.