So i'm looking through my nitrous install directions and notice that in order to run a 75 shot I have to retard the ignition 4 degree's (retarding ignition=adjusting timing, correct?).

But, isn't it true that on our cars we cannot adjust the timing (or retard the ignition) since its controlled by the ECU? So would it be ok to run this 75 shot without fucking around with anything? I'm aware that I need 2 degree colder spark plugs, but this has been buggin me a bit since this is the shot I wanna run at the track.

 

Someone correct me if im wrong but on our cars we can only take timing out with electronic controllers. (timing cant be advanced on our cars with them)

 

So what are my options? Should I just run a 55 shot which doesn't require anything to be changed?

 

Where are all the other guys running nitrous?
People love to show off their cars and talk about retarded things like where to put trash bags in your car... but it takes forever to get definite answers to legit and useful questions... *sigh*
Except for fsttyms1. He knows his stuff. Hehe.

 

^Werd.

Here is a interesting thought, when people fill up with 87 octane instead of 91-93 octane, the ECU adjusts the timing itself to prevent knock and detonation. Wouldn't this be the same case?

 

Posted on almost every forum I attend, still no real answer. From what I gathered through some of the responses, some say its ok to run 75shot and not touch timing, while some don't recommend it.

I read some "Nitrous 101" guides, and found this to be pretty interesting/helpful
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"Timing plays a key role in the performance of a nitrous kit. Due to the increased cylinder pressures, it's unnecessary and highly inadvisable to advance the timing as much as a normally aspirated performance engine. Overly advanced timing leads to detonation and can cause severe damage to the engine's internals. Anyone who has advanced the timing too much in any engine has heard the dreaded knock and ping.

How much timing change you'll need will differ according to engine condition, bottle pressure, even weather conditions, etc.

As a general rule of thumb, 1 degree retard for every 25 HP is common.

EFI engines may not need an adjustment to the timing up to a 100hp as the ECU may automatically compensate for any minor adjustment / requirements that are needed.

For carbureted vehicles general guidelines below may be followed:

Up to 50 HP use standard timing
50 to 100 HP retard by 2 degrees
100 to 150 HP retard by 4 degrees
150 to 200 HP retard by 6 degrees
250 HP and up retard by 8 degrees

From these baseline points if no detonation is experienced gradually increase the timing until detonation occurs. At which point retard the timing by 1 degree as a safety margin.

Companies like MSD, Crane, Jacobs and Mallory make ignition systems that are designed for use with nitrous. MSD's Digital-6 Plus ignition box has a single-stage retard built in that will automatically retard the timing when the nitrous is on. MSD also offers a Digital Multi-retard that features four stages of retard. According to MSD, "Each stage is adjustable from 0-9 degrees of retard and a maximum of 20 degrees can be pulled out".

 

There is atleast one guy on the 2nd Gen CL board running nitrous, if I come across his user name, I'll post here, but look over by us and you may get your answer a little quicker.