Contour Enthusiasts Group Archives Forums Modifications Forced Induction Nozzle Placement

Originally posted by Tourige:

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Originally posted by warmonger:

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Just far enough back to get a good distribution of N2O and fuel before it hits the divided upper intake plenum.
I think after the throttlebody is too close. In the accordion or in the outlet of the maf sounds fine for a basic kit.

If you wanted better performance you could run dual nozzles, one in each inlet of the manifold right where it splits. This keeps less thermal expansion from the N20 heating up outside the manifold and will equally divide it between banks. It would be more efficient on all fronts.
Instead of one 75shot nozzle you can run twin nozzles with 35 shots and drill them into the manifold right at the corners. Make sure the lines going to each nozzle are exactly equal in length for both fuel and N20 as compared from bank-to-bank, and as short as possible.


Don't forget the bottle heater, fuel pressure cut-out safety valve, and probably a electric cut-off at the bottle for the best safety.

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If your going to drill into the UIM might as well do a proper Direct Port and drill into the UIM above each port and run 6 different nozzles.

I just dont think it will clear the stock hood.

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Agreed that direct port is the "best" if you mean most power output available, yet all methods are "proper" if setup correctly. However, direct port is much more complicated than a single jet/nozzle setup. There is a point of diminishing returns with any setup and that would be where the cost and complexity begin to exceed the benefits, and I think the direct port is beyond this point. Each proper method has its merrits but depends on what is important to the designer.
Let me summarize why:
There is nothing wrong with the single jet/nozzle mounted in the intake, it works well. However it has the limitation of having to being far up the intake tract which gives the nitrous more time to absorb heat and expand before getting to the cylinders. More heat and expansion upstream = less power downstream (not that you're lacking when you are running N20). So optimally you want to get closer. Good mixing is more important that having a cooler charge and that can only be accomplished far enough away from the split on the UIM. So you're stuck.

Direct port for an engine like ours would require twin lines per cylinder for a wet setup, a setup that I personally think is the best. A dry setup at least one line per cylinder. That can easily be done UNDER the UIM with a gasket spacer! So I don't think hood clearance is your issue, the issue is the costs.
And why do it? Just to get the most efficient version of a 100 shot maybe? Not worth it. Noone is nitrous dragging this engine on a built motor where a 250shot or something could be used in a rear wheel drive car. 100shot is about it usually. <Gosh, when I think of how easy it would be to implement so many cool ideas when money ISN'T an object, I just want to be rich>

So my idea was a compromise that satisfies three assumpitions:

- closer to the cylinder by almost a foot and a half equals more time in the engine absorbing heat and expanding=more power for a given shot.
- even distribution, twin nozzle/jet setups so that each bank gets its own half of the fuel/nitrous mixture
- Fairly simple and straight forward as it would require only two brass T fittings at where it splits to both nozzles, and an extra jet/nozzle fitting. Added costs less than $100 easy!

So the most expensive part of the wet kit is the jets/nozzle parts assuming you've got to have a fuel and nitrous solenoid ANYWAY to get it to work. So whatever the jet/nozzle cost is, you would go x2 on the cost for this idea...........as opposed to x6 for the direct setup.

Now picture the last part, by doing direct port into the UIM you greatly increase the cost and only save yourself a couple of inches of travel distance for the nitrous and air. Better to leave it alone. The twin jet setup makes up most of the distance already and is cheaper and simpler to setup.