hmm, how do we calculate duty cycle? i build mostly carburated MX race motors and the motors i do on 4 cylinder streetbikes doesn't require me to change anything with injectors.

This area is new to me with cars. Tim showed me the calculations for pressure, but i don't know how to calculate flow or duty cycle. So i take it to get the correct flow ours have to be about 97psi. If we drop that pressure then the flow rate isn't higher so the injectors work harder, correct? If that is correct then I think Tim said we need 550's to get the correct flow with a 4:1 but our pressure would be a lot lower.

So what calibration kit do you have now? I think it's around 40$ for a single recal but if you get the whole kit of them it's around 55$. It might be better to get the whole thing then you could test it. If i had a 4:1 i would test it and log all the data.

Anyone want to donate a 4:1 recal ring and washer?

 

i dont know how to calibrate it but i know it would be very high and not the safest thing to do...550's would be needed thats for sure to keep it safe...i have everything right now from the 440's, machined 2.87 pulley, gtm pulley mod, fuel pump, i am just figuring out which recal kit i was gonna go with, but maybe ill get the whole kit and sell the 440's to get 550's

if u drop to a 4/1 now it is gonna cause th injectors to work harder and they will be maxing out, and it is not recommended to run over 80% duty cycle, i personally think the setup u have now is fine, but to be even more safe and lower the psi it would be good to do 550's and the 4/1 kit

 

im told the ss box can also scale the 550's fine also so maybe thats what ill do

or just stay with the 3.12, and keep the 440's and do the 4/1 and do the 2.87 down the road when i get some 550's

 

ya, i think if i decide to change anything i'll just wait until the winter and do the whole "big injectors, standalone, return fuel system".

Thing is, the SS box doesn't hold anything more than 550's so i'll have to get a new ecu, might as well get something nice like a haltech or fcon if i'm doing that. Then since i have that i might as well get huge injectors so i won't have to upgrade ever again, and while i'm doing that, return fuel system would be advised.

So ya, for now, i'm thinking i won't do any upgrade to it since i'll end up just upgrading again when i want more power. Best to just wait it out and get the whole thing at once.

I'd say for you, the 6:1 is going to work fine. 4:1 nobody knows yet. If you get the kit i'll do some logs and if it works then it works. If not then you have extra parts for later. I wonder if we could use a 5:1. They have that "air bleed valve" that says you can adjust 1-2 psi lower than the calibration ring. With that you could get a 7:1 and then set it down to a 5:1. I wonder if that would be a happy medium. Not maxing injectors but lowering fuel pressure.

 

2.87, 440's, and 6:1 works great.

It's a very solid setup and yields some awsome horsepower. If you order rings then get the whole kit since it's only like 10-15$ more and you get a whole bunch of them.