August 2010 Chevy High Performance Q & A - Performance Q & A

Kevin McClelland Jun 17, 2010 0 Comment(s)
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Good luck sealing up your little small-block. Following the above practices should give you a leak-free seal. Sometimes it's tough to find Gasgacinch at your local auto part stores. Edelbrock has sold Gasgacinch packaged in its containers for over 30 years and can be order under PN 9300 through any of the mail-order outlets


Saftey First
Q: I recently bought a used NOS Super Powershot kit with a bottle heater and purge valve kit, and I want to make sure I am doing everything right. It's going on my '79 Malibu. The motor is a 350 with a stock bottom end, cam specs unknown (very mild), a 670-cfm Street Avenger on a Edelbrock Performer intake PN 2101, Hedman full-length 1 5/8-inch headers and 2 1/2-inch dual exhaust with an X-pipe running through Flowmaster Super 40 mufflers. The rest of the drivetrain is a TH350, soon to be replaced with a TCI TH700-R4, an 8.5-inch 10-bolt with 3.42:1 gears, and the tires are P245/60R15. I've never run nitrous before but have read quite a bit about what is needed. I was planning on starting at a 75 shot and not going any higher than 100. Any advice you could give would be greatly appreciated. Mike Senay Pitt Meadows, BC, Canada

A: You're taking the right approach by reading up and asking questions on the front end. Nitrous power can be intoxicating, and moving up the jet sizes is very easy. Let's go through this for things to look out for.

First of all, you'll want to make sure your fuel system is up to the test. Nitrous is an oxidizer and carries no energy (fuel) with it. Any power increase made with nitrous must be accompanied by additional fuel. If not, it can be just like a cutting torch burning through pistons and blowing out head gaskets. It's not a pretty sight. The factory fuel delivery system on the '79 Malibu is weak at best. The fuel pump barely keeps up with a stock 350, not to mention one with some performance add-ons. You'll want to upgrade the mechanical fuel pump to a Carter mechanical pump PN M5900P, from Jeg's or Summit Racing. It's very user friendly, delivering 5.5 to 6.5 psi of fuel pressure and doesn't require a fuel pressure regulator after the pump. It will deliver 120 gph fuel flow, feeding your 350 and small nitrous system with enough fuel.

Now that we have enough fuel to feed the beast, let's look at the nitrous side. Since you are the second owner of this system, look over all the solenoids and make sure that nothing is plugged or stuck. Also, some of the AN fittings feeding the solenoids may have stainless steel screens to prevent trash from entering the valves. Check that all screens are clean and clear. When installing the bottle, lines, and hardware, purge a small amount of nitrous through the line before connecting the feed line to the nitrous solenoid. This will blow out any trash that may be sitting in the long feed line from the trunk.

Using a bottle heater is the best way to maintain the optimum 900 psi of bottle pressure. The nitrous system jetting is based on a nitrous line pressure of 900 psi and approximately 4 psi of fuel pressure. This gives you a safety margin. If the nitrous pressure drops below 900 psi the mixture from your system will be on the fuel-rich side. Conversely, if the fuel pressure drops below 4 psi you'll be lean on fuel and damage could occur.

Small nitrous shots (75-100 hp) won't require you to retard the ignition timing. Any higher than 100 hp and we'd recommend retarding the timing approximately 4 degrees for a 125hp shot.


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