Supercharging & Nitrous Oxide?

[Romefu12]

Gentlemen and Ladies as well;
I have a personal project underway and before I make any capital investments I have come to ask the experts their opinion in this forum. My project is a 1988 Ford Thunderbird toy project car that I have owned since new. My objective is to build a 351 stroked Windsor Block with 2 power adders. My scheme is to supercharge the engine approximately 10 to 14 psi using a twin screw supercharger and use a shot of Nitrous for special occasions. I have heard many stories and rumors that this practice of using 2 power adders is used quite frequently although it is not NHRA legal however I have never seen these 2 power adders used successfully together in person. My question is this “Can Supercharging and Nitrous Oxide coexist and be used successfully and perform with reasonable reliability in this weekend warrior project?

I invite all to respond with their opinions, pros, cons, and technical expertise.
Thank you all in advance for your inputs

Romefu12

 

[patdaly]

Sure it can, given the right parameters.
I would question any one who would call a stroked 351 10-14 PSI plus Nitrous a "weekend warrior", because this thing isnt going to be much fun to drive on the street.
I would get from whatever manufacturer your Supercharger is going to be a chart of the effective Compression ratio at 14 PSI, and treat it from there with regards to Octane requirements. I would also look closely at an aftermarket block.

A good primer for you would be a gentleman by the name of Mike Sitar,

http://www.toohipsi.com

Nice guy, could help you out a bunch.
Good luck, and let me know whatever tire manufacturer you choose to run, I want to buy stock before it goes up!

 

[patdaly]

Whoops, my bad, site is:

http://www.toohighpsi.com

 

[patprimmer]

Nitrous works very well with a turbo, as it eliminates turbo lag, then as the boost builds, pressure activated switches cut the nitrous and thereby keep it reasonably economical.

On a supercharged car, the blower can be sized for normal use on pump gas, and the nitrous only used for special occasions when you have high octane gas.

Unless you are going to run some good fuel, you only want about 7:1 comp at 14 # boost. It also depends a bit on chamber shape and preparation and any charge cooling you might use.

Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Romefu12]

Gentleman
The supercharger I am leaning towards is a Kenne Belle Blowzilla 2200 however I am not through researching the pros and cons of all of the manufacturers as yet. I am also looking into the SVO Sportsman Block and a forged rotating assembly. I figure on no more than 12 psi boost however sizing the supercharger to be efficient and reliable with a little more capability than I will actually need is the smarter approach.(If I become a little braver later I can change a pulley and adjust octane to suit)

From Patprimmer's reply, this is the first time I had heard of pressure switches for turning off the Nitrous. This I guess when I think about it further, would be extremely necessary.

Romefu12

 

[jons999]

Blowers and nitrous work great together. It just takes a little bit of work to make the engine safe and reliable. I would recommend using and aftermarket ecu (if your using fuel injection) as well as programmable nitrous controls that you can use to adjust the amount of fuel and nitrous being added as well as retarding ignition timing when your on the bottle. Then get the whole thing tuned on a dyno at a speed shop to make sure your not running too lean.

-Jon