NOS vs Alky

[ed39]

every one seems to swear by the alky kits. but i had a car come in to my shop today (WRX aka slow) and he had a nos setup up exactly are alky kits, ware it comes on with boost. now i know NOS could keep the charge way cooler than alky ever could. anyone doing this or am i completly wrong?

[PaCemkr86]

it works, no doubt, but bottles are expensive to get filled and maintaing correct bottle pressure etc.. and the added stress on your fuel system whether it be a dry or wet nitrous system

where as alky is cheap and easy to get almost anywhere and once ya tune it, ya leave it alone, just keep the reservoir full

[PhillyTurboSix]

It's actually simple when it comes to these cars about NOS or Alky...

NOS = BOOM

Alky = FAST

[kenmosher]

Well, N2O ... (pet peeve of mine ... NOS = brand name and the ricers all think it's NAWSSS ) ... anyway ...

... will work with a turbo, but there's only so much cylinder pressure you can hold. As a result, you can either pump a bunch of nitrous in (with the additional fuel) and turn down the boost or just use the nitrous as a small adder on top of boost. In the latter case, it's biggest contribution will be like an intercooler in a bottle. It can also help spool big ass turbos on the line.

The caveat with N2O is that you HAVE to have the tune right on the money ... boost is a more gradual "hit" to the rotating assembly ... nitrous hits hard right away. If the tune is off a little, detonation with nitrous = pounded out bearings, or worse, cracked main caps.

Of course, detonation with boost is bad too, but tends to give you a little more "leeway" and usually give you a couple "mulligans" before you beat the life out of the bearings.

There's nothing inherently evil about nitrous, and if tuned for and used correctly, it can be a great power adder, but as Phil stated above, there's a lot of screwing around with it. It's not something you can easily just "plug 'n play" (at least to do it right).

That said, I ran it back in the early 90s on my basic Recipe car (as did my buddy Chuck) for one season. At the track it took my 12.50 car and IF I could match the fuel jets and N2O jets correctly for the air, the car would go 11.70s @ 113-114 MPH (vs. 12.30-12.50 @ 107-109 MPH). We made up a spreadsheet of different jets vs. density altitude and such. If you got the fuel jet a little rich (the safe side), you risked a kind of "lag" when you hit the button as the car tried to adjust to the overrich fuel/N2O.

We would turn the boost down to 16-17 psi and then inch up in N2O/fuel jet pairs until we saw about 20-21 psi on the boost gauge when you hit the button. This seemed to net the best ETs (and we ALWAYS ran on race gas and watched for any kind of retard). SO... for on the track, it worked pretty good on a stock turbo, stock intercooler, stock injector, car. It also helped make up for bad air (hot, humid, etc.).

The downside was it sucked on the street... it was never right for the impromptu "stoplight Gran Prix" . Bottle was low, heater wasn't on, main valve was off, jets were wrong, street gas, yada yada yada.

After a year, we both sold our set ups and went with the (then new) hybrid turbo/heads/cam route.

[Keller]

Stuck this thread. Ken's writeup (which I've seen most of before) should answer any future inquiries.

Originally Posted by kenmosher

If the tune is off a little, detonation with nitrous = pounded out bearings, or worse, cracked main caps.

And Ken knows this for a reason...

[kenmosher]

Always learning the HARD way!

[Keller]

Its easier if Ken breaks it first and saves us from doing it.

My head gaskets thank you.

[ed39]

i understand the single shot idea and the extra bull crap, but this set up was like the alky setups ware it comes on gradual with boost he had this weird valve setup on the bottle so it acted the same way the alky kits work, i will never try this but i was curious ill go with the alky kit

[kenmosher]

Well, excuse me for the "bull crap".

But what you described is just a standard progressive nitrous system. It's hardly anything new or unique. Simple PWM solenoid controller and been around for years with it's own problems and challenges.

I designed and built one using the DashHawk as a controller for Edge/MSD and we decided not to market it.

[ed39]

your write up was good, i had never seen this set up before and it seemed like it would do a wayyy better job than alky could ever dream to do,im not a nos fan at all it just seemed different


by bull crap i meant the extra lines,pressures,expense etc......