RX7Club.com - Mazda RX7 Forum

RX7Club.com - Mazda RX7 Forum (https://www.rx7club.com/)
-   1st Generation Specific (1979-1985) (https://www.rx7club.com/1st-generation-specific-1979-1985-18/)
-   -   Nitrous Jetting, how much can a 12A digest? (https://www.rx7club.com/1st-generation-specific-1979-1985-18/nitrous-jetting-how-much-can-12a-digest-51735/)

sbrx7 02-06-02 09:19 PM

Nitrous Jetting, how much can a 12A digest?
 
OK gang, time for a more specific nitrous question. What sort of jetting, fuel and nitrous, are the masses running? I have a set up in place with two fogger nozzels installed in a RB two piece intake, and the jets the manufacturer supplied appear to be to big. Even with the smallest jets in the nitrous side, the engine falls on its face when engaged. Free rev, the system can be purged and it picks up revs like one would expect, but under load, it just croaked. Ignition is still a question, with some better parts going in tomorrow. Aftermarket coils needed? I have the colder plugs in, and plenty of fuel (Holley blue, dedicated to nitrous nozzle) and fuel pressure (6.5 psi). Nozzles are Compucar foggers. current jets are 22 nitrous, 25 fuel. (yes, I know that's lopsided, but we just wanted to see if it work function at all) Dellorto 48, RB header, 2 1/4 pipe striaght back to 2 1/4 flowmaster (yeah, it's loud).
As you can see by my question "50 shot and 75 shot" aren't going to help, I need some hard numbers. THe guys at the speed shop say the bikes are running jets in the teens, since our displacement is similar, should we try that?

Thanks in advance, time is of the essence on this one!!!

Steve Bertok
85 GS on the juice, baby!

MIKE-P-28 02-06-02 11:11 PM

Dunno if this helps ya, I know nothing about it, but I found this while looking for info on my new swap :)

http://home.earthlink.net/~burntoast/nos.html

fastrotaries 02-07-02 01:57 AM

Try smaller and work your way up. Also try giving RB or RP a call, better yet Mazdatrix. Eventhough they're not doing too good with their N2O drag car set up.

jbontke 02-07-02 12:53 PM

In my opinion your fuel jet is way to big. It falls on its face because you dump too much fuel in the car. You need a really good AF meter to watch AF ratios if you are going to goof around with that stuff. If you didn't have a big enought fuel jet you would have burned the engine up. Nitrous will work with out enough fuel, but not for vey long. You need to call some people who have allready run nitrous on their cars. Try to find someone with a setup like yours. If you over fuel the car you will foul plugs very fast and the car will run like crap at idle. If you under fuel it it will burn up spark plug electrodes and your engine. A good AF ratio with nitrous will keep the engine clean of carbon and make the safest HP.


All times are GMT -5. The time now is 09:43 AM.


© 2024 MH Sub I, LLC dba Internet Brands