Author Topic: Top shot nitrous kit with quadrajet?  (Read 943 times)

Offline v8440

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Top shot nitrous kit with quadrajet?
« on: October 10, 2022, 06:13:49 PM »
Hi all,

     Can it be done?  Kit instructions say not to use on any non-mechanical secondary carburetor such as a quadrajet.  Will it really end in tears or can it be done if the secondaries are in fact open?

Offline Kenth

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Re: Top shot nitrous kit with quadrajet?
« Reply #1 on: October 11, 2022, 01:46:37 AM »
FYI, Quadrajet is a mechanical secondary carburetor with an air valve feature.
And, yes it can be done and has been done.

Offline v8440

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Re: Top shot nitrous kit with quadrajet?
« Reply #2 on: October 11, 2022, 04:54:08 AM »
You're correct, I was just repeating what the instructions incorrectly said.  They probably assumed because the whole secondary system doesn't snap wide open when the accelerator pedal is floored that it's a vacuum secondary system.  In any case, I'm glad it can be done with a quadrajet.  I have a '73 sedan deville that I want to outrun a buddy's '92 foxbody mustang with, and I want to hit him with it out of nowhere.  It's all in good fun, he's not a braggart or anything.  I also partly just want to see if I can do it.  If I beat him, he'll look for and notice a nitrous plate.  A top shot, not so much...

Offline v8440

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Re: Top shot nitrous kit with quadrajet?
« Reply #3 on: October 11, 2022, 06:21:41 AM »
I'll lay out the whole situation as it looks presently.  Car is '73 sedan deville, stock 472 engine.  Plan is to run stock manifolds, intake and exhaust, with dual exhaust instead of the single hiss-fest stock 2 1/4" pipe.  Here's where it gets kinda hinky:  I just happen to have a davis technologies traction control system sitting around.  Assuming I can get a reluctor wheel to fit the pinion yoke of the cadillac, I plan to install that.  However, instead of using it to just retard ignition timing (going to be using a digital 7 msd box I also have sitting around, triggered off the stock points setup in the stock distributor) I plan to use it to tell the nitrous controller to pull back the nitrous when there's wheel spin.  There is a controller available that can do exactly that, using the davis system as wheel spin detection.

Fortunately, that nitrous controller also allows a delay between full throttle switch being closed and actual start of nitrous injection.  I figure that feature will allow me to delay the nitrous such that the secondaries have had time to open, which in turn can be fine tuned with the clock spring and choke pull off delay.  A weird combination of very old technology (points ignition) and pretty advanced (traction control and progressive nitrous).  Getting away with a top shot instead of a plate would be the icing on the cake.  If any of you have some guidance as to how to best use a top shot safely on a quadrajet I'm all ears...