SR-24

What's the best sytem out there or are they all pretty much equall and what is the best and simplest device on the market to retard timing before hitting the button?

WETTE VETTE

I have studied this quite a bit and installed a Sniper NOS system on my dads small block powered Baja. We run an Edelbrock race mechanical fuel pump with the carb set at 8 psi and the NOS set at 5.5 psi. The motor has a full MSD iginition and we use MSD PN 8982 that has a start retard and a single stage of timing retard. We also use a fuel pressure switch, a WOT microswitch, and an arming switch in conjunction with the throttle mounted button. We run the motor at 38 degrees natural and pull 5 degrees when on the NOS. At 100 HP the boat gained 5 MPH. We are still experimenting with the 150 HP jetting trying to get it maxed out. On your motor I would run your stock fuel pump and tee in a M110 or M140 electric pump. Tee the outlet into the main fuel line that feeds your carb and from that same line break off into your regulator for your NOS. These pumps are dead head type pumps and can be run all the time with your mechanical pump. Then you could basically set it up in the same manner I just described and will have a very safe and effective system. Note it isn't a good idea to hit the gas until the motor is turning 4000 plus RPM. Good Luck!!

SR-24

Thanks for the advice. Do they list that MSD part# in the Summit catalogue? How does it work? That would be my next question, can I hook up some kind of retard device to the Thunderbolt IV?

WETTE VETTE

Yes this part is listed in the Summit catalog. It works with MSD ignitions only as far as I know.

OkieTunnel

SR-24, You should talk to Wyatt some more if you haven't already, he has run a lot of nitrous systems on boats although I don't know about EFI boats. I am using a shop here in OKC called HP racing equipment and they seem to know alot about putting nitrous on EFI. They are about to install the blower I was talking about in the other post. They told me not to run nitrous and blower on my 454 but that they would recommend and could install either or.

deboatmon

Wette Vette sounds like he's had considerable experience with Nitrous. The key word there is " considerable" experience. Nitrous is a powerful thing and can be useful when all key support ingredients are there. There are so many things to be aware of it's impossible to list them all here. One thing that can sometimes be overlooked is the rev limiter. Many MSD users have the plug in rev limiter. You probably should just eliminate a rev limiter when using nitrous. If you hit the bottle and get into the rev limiter, you'll blow the heads off your motor.

Nitrous for the boats commonly found on this site is extremely rare. There's a good reason for that. It's not a good long term power maker. I would not come close to a nitrous bottle on my present boat. Fifteen years ago I had nitrous on a Sleekcraft jet boat and used it regularly. Jet pumps are impervious to sudden and radical power changes. Outdrives are much less tolerable of the same. But, anything done well has a chance of survival I guess. Just make sure to work with someone with lots of experience.

To each his own. I'm forever weaned from the bottle.

WETTE VETTE

We run solid roller cams in our motors and have the rev limiters set at 7000 RPM. On the NOS we are seeing 6500 to 6600 RPM. The limiter is there in case something in the drivetrain breaks. No revlimiter in this case would be as bad as is hitting the limiter on the NOS. In this case you have to choose which is more likely to happen if a drive breaks at WOT on the gas. Can you pull out of the throttle fast enough to save your valvetrain? No human is fast enough to pull the throttle back in this scenario, so we run the limiter. I have seen motors hit the limiter on the NOS at the strip and survive, but it certainly isn't recommend. For that matter staying out of the rev limiter is always good NOS or not. Max RPM must be considered when running NOS. Most stock motors do not have valvetrain that can handle much over 5800 RPM. You may have to prop accordingly. We just use our fastest prop and zing it on the NOS. We run slightly colder plugs than stock as well. Good luck and be careful!

SR-24

That was another question I had. Given the same prop and adding a 150 shot of NOS how many rpm's would you gain?