Small block motors

[John Scott]

I'd just hate to see someone unfamiliar with boosted motors try and run hyper. pistons just because someone else does. The GN and Syclones came with hyper pistons, but also with sophisticated manufacture designed engine management system. Hopefully everyone will address thier projects as carefully as Scottie. For those of you w/o the high tech datalogging, O2, knock sensors etc., the avaerage Joe who's going to bolt on a supercharger and try it, spend the extra on forged.

[Kevin Shasteen]

I'm not a wiz-kid at supercharging, turbo'ing or nitrous. When you guys start talking about Chrystal Power, Space Time Continuem & Anti-Matter...you lose me. However, I do read a lot on performance & wont make a decision until I understand an issue.

 

Its funny this subject came up as I was reading about nitrous & its hazards just the other day. The book is Chris Jacobs's latest book on Performance Ignition by HPBooks. He lists the 5 major causes of engine failure using nitrous:

 

1) Over-Reving: This is a problem w/any engine but especially a nitrous driven engine as the breaking point is reached much quicker-only resolution is a ref-limiter. Yet rev-limiters limit rpm by cutting off the spark; if un burned nitrous is not ignited as spark is limited; then its once spark comes back on your Exhast is an instantaneous Combustion.

 

2)Lean-Out: Nitrous releases extra oxygen when being burned & will eat any metal when in contact while burning. If fuel is lean then nitrous will turn to your piston tops & valves.

 

3)Detonation: He claims that most drivers are not familiar w/detonation in a nitrous powered car-its not the usual "Elves W/Hammers On Top Of Your Pistons" sound-instead, w/nitrous, detonation will sound more like a "Rumble of Distant Thunder". Also said any engine running both on & off nitrous needs two timing curves to survive.

 

4)Misfires: Nitrous is more difficult to ignite than gas & air. First-the same reason a ref-limiter is dangerous w/nitrous so too is a misfire-this could cause the same problem when misfiring. Also, When a misfire occurs it creates the "Jackhammer" syndrome which causes one cylinder after its Ignition Stroke to oppose next cylinder firing: yet in a nitrous ignited engine this is much more detrimental than a NA engine.

 

5)Too Much Nitrous At Too Low an RPM: A Nitrous System big enough to give you real benefits at the hight end will break a motor if used at too low an rpm. The lower the engine rpm, the longer it takes for the piston to move down, so the more nitrous is in the combustion chamber when ignited. Hence, the lower the rpm the more violent the explosion. If this is done at a low rpm the nitrous overfills the chamber, when overfillin is ignited-it breaks the engine. Nitrous ran engines need a more precise dependable ignition system.

 

Having read you portions from his book; he goes on to state what safety features should be installed in a nitrous system:

1)Master Nitrous Safety Check-off Lists

a)Limits maximum rpm to a safe lever & shuts off nitrous/fuel enrichment before cutting spark

b)When fuel pressure gets too low-the system will shut off the nitrous

c)Must shut off nitrous first before shutting off the fuel

d)When running both an on/off switch-a nitrous system needs to incorporate a timing retard/advance mechanism too eliminate detonatiion when in use & when not in use.

 

Scottie; I envy you & others who do understand nitrous; I would just caution those who dont to make sound judgements when choosing something outside your realm of understanding.

 

Now after saying that; Beam me up Scottie!

 

Kevin,