Warning!!!!! : Manufacturers recomended jetting
Originally Posted by 383LQ4SS
In response to the other thread about the blown motor...and a few other recent stories I have heard....manufacturers recomeneded jetting is just that. A recomendation for a starting point to get you close on Af ratio for a certain size shot.
You guys have to keep in mind that these are just starting points. IMO it is still up to the end user to get on a dyno with a wideband...or use an onboard wideband to check the ACTUAL AF ratio. Many many times you will find tweaking the actual jets will be required. If nitrous manufacturers could control all possible variables they would state with a certainty to use a specific jet under all curcumstances. But there is too many things that can change to have an affect on a combo. So IMO its rule of thumb to check your ACTUAL AF ratio after every install..AS WELL AS regular intervals from time to time....or when you feel its not running right.
IMO this goes for a 50 shot on up. Just dont take the chance. Yes...9 times out of ten youll get away without checking....but who wants to be that tenth guy?
Most here know that..I just wanted to reiterate this point for some of our newer lurkers.
You guys have to keep in mind that these are just starting points. IMO it is still up to the end user to get on a dyno with a wideband...or use an onboard wideband to check the ACTUAL AF ratio. Many many times you will find tweaking the actual jets will be required. If nitrous manufacturers could control all possible variables they would state with a certainty to use a specific jet under all curcumstances. But there is too many things that can change to have an affect on a combo. So IMO its rule of thumb to check your ACTUAL AF ratio after every install..AS WELL AS regular intervals from time to time....or when you feel its not running right.
IMO this goes for a 50 shot on up. Just dont take the chance. Yes...9 times out of ten youll get away without checking....but who wants to be that tenth guy?
Most here know that..I just wanted to reiterate this point for some of our newer lurkers.
HP N20 Fuel@10PSI
35 - 31 - 24
50 - 35 - 26
75 - 41 - 28*
I ended up needing 18.5 PSI of fuel to get the right AFR of around 11.5-11.8 .
Originally Posted by 383LQ4SS
You likley wont need any extra jets. Once you determine your AF ratio...let that guide you. And many times youll have the jets required in the kit.
My plate came with 50-200 jets.
Thanks a lot
Teching In
Joined: Dec 2004
Posts: 31
Likes: 0
From: SoCal
I ended up needing 18.5 PSI of fuel to get the right AFR of around 11.5-11.8 . // H/C and Nitrous. 408 and a big DP shot in the plans.
408ci div by 346 =s 1.179 difference in size and most likey power output
you will need 18% more fuel to make 18% more power