I have been wanting to go NOS but saw a post were someone miss shifted & blowed there motor. OK there is dry & wet shot NOS systems. We have CDI's with rev limiters & not. Is there a combo that works to keep the motor from blowing up if you miss shift? I have a boondocker NOS (not installed yet) system & a vortex CDI (which has been reprogramed) . If my CDI is set at 9,000 rpm's with shim under bucket springs & I miss shift with NOS (boondockers or others) will I blow my motor?

 

Country, if I understand you.... you are asking - if you rev too high will you blow your motor? Obviously you run that risk when ever you rev super high. Obviously 9k isn't huge, but with the addition of NOS the motor will tend to grab RPM quicker when the button is pushed. Maybe the better question should be, is it hard to come off the button after you miss a shift? Two kinds of systems.... Systems that are triggered via a micro switch, and button activation systems. I used the button, but the Straight Racers like the micro switches. Obviously the mirco switch is ideal for racing, but the switch only works for the very, very last part of the throttle pull. In that split second, could you over-rev and cause havac? Yes, but it's not like the motor will rev 3000rpms in a 10th of a second. You have control of the throttle and it would be as easy as letting off the gas as you normally would (micro switched version) if you missed a gear. If you are on the button, you'll definitely have your hands full, so be mindfull on the pull. Quite frankly, you should probably shifting before 9K anyway.... unless your monster is making gobs of power at 9K. My 730 likes it from 5k to 7.8K. After that, I'm usually looking for a gear. Being honest though, I'm always running it around 8 - 8.5. Just really doesn't stop pulling too much before that.

Hope I helped a little. I'm sure others will chime in.

 

I think the ignition timing is more important that the revs. I have found that your power band increases by 1000RPM on the bottom and on the top when running nitrous. But if your ignition timing is too advanced, and your other variables are not right on, this leaves you open to pre-ignition.

 

I dont really understand much of this advance/retard timing bit for nos/turbo applications. The little I have kinda understood is how retarding the timing for boost will not harm the motor as much as TDC is already past and the torque is being made farther down the power stroke...but putting it all together as to why SOME peaple want LESS TIMING at lower RPMs and others want LESS TIMING at high RPMS I dont understand. As far as timing for NOS I dont have a clue.
I thought the RPM activated window switches would be good for NOS but have not heard much talk about peaple using them.

 

Advance in the beginning will produce more usable power down low, and retarding on the end will produce more usable power up there.

Oregon is also correct. Timing can be a killer ESPECIALLY with NOS. If I had my drothers, I would Retard the timing at the top - specially if I were experiencing any pre-ignition. I'm not, but then again, I'm at $6.00 per gallon for leaded racing fuel. Cams can also help in this area.... if the cams are relieving pressure at a good rate via lift and duration, they will relieve cylinder pressure and help the Juicing...

 

Thanks for the replies!

 

Joe, Great question. I have been tossing the idea of the nos application for my bike. But I have heard that some of the cdi boxes make it way easier to hurt the top end after a missed shift. Vortex being one of them. Would a cdi with a rev limiter be better for using nos?? As to prevent over rev?

Dont know if it was answered or not, Is the dry systems more forgiving with higher revs or is the wet system?

Which is easier to tune?

 

The Vortex CDI can have an alternate curve programmed into it for that exact application and retard the timing. Over all the best thing to do is go slow and start with the smaller shots until you have become used to it and how it effects your ride. Also making sure to be very dilligent about making sure your carb is tuned correctly, as well as your nos system (fuel tuning on the Boss Noss, and pressure and monometer on Boondockers). It is all a matter of paying attention to your bike as a whole, and making sure they are working together.

Nos is my next venture, and have been doing extensive research on it. I am going to go with the Boss Noss system as to me it has less room for error, and like I said with the Vortex you can have a specific timing and curve programmed.

 

I have heard that to. My MSD has the option to set my advance curve and how much peak advance anywhere up to an additional 7 degrees (32 total). It also has a feature that allows you to retard the timing up above 7000 rpm I believe. With the programmable Vortex they ought to be able to program that top end retard to help curb detonation.

I also read that Hard1 was running 110 octane on all motor but Sandbomber was running 118 on NOS. Are they further advancing timing and solving the detonation problem with octane?

I wonder if the slower burning fuel is also less likely to lean out?

Ron

 

My understanding is that the higher octane does help to control everything. Boondockers (for instance) recommends 3 octane over your build requirments. Also a change in the spark plugs is recommended by most that I have read also. Keep in mind my information is based on my internet research, and not real life use......Yet