fmu change question

**nstycpe93** · 11-29-2002, 12:02 AM

at the present time this is my mods:

edelbrock rpm heads 2.02/1.60
edelbrock rpm intakes
mac long tubes
30lbs injectors.
70mmtb
87mm maf
e cam
f150 pulley
seeing 8-9 lbs now on the novi 1000.

i was wondering if you had to make changes in the fuel management unit to accomadate the 30lbs. yes i have a 255 pump in the tank. but doesnt the ration need to change in the fmu. does paxton sell the kit like vortech to change the air/fuel ration?

thanks for the help..

**TheHawk05** · 11-29-2002, 12:26 AM

I had this question as well for my system as I'll be running 30lb injectors. Your FMU needs to be changed if it is the one that came in your kit as it is designed for the stock injectors and will therefore make it run way rich under boost. Unfortunately Paxton doesn't sell recalibration kits for their FMU's. I'm not sure if the Vortech kits will work in the Paxton unit. You have a couple of options here. You can buy a Vortech FMU with the proper calibration or a Vortech Super FMU which is a much more tuneable FMU and will grow with your combo if you upgrade down the road. A lot of people will tell you your injectors might be too small but you'll be fine with the boost level you are running as long as you use an FMU. You can also get rid of the FMU altogether but this WILL require larger injectors ( 36lbs or even or even bigger if you add boost) and a dyno tune to have everything right in my opinion. Naturally this will cost a good amount of cash. If you're on a budget like most of us are these days, I would just get the proper FMU for it and stick with the injectors you have. Check around on eBay as you can save yourself some cash getting one there. Your in tank pump is fine for your combo.

**468LC** · 11-29-2002, 12:42 AM

My own personal opinion is to do everything in your power to NOT use an FMU even if it means new injectors. The drivabilty is sooo much better in my experiences.

I have personally had both the paxton and vortech FMUs apart side by side and I can not find a difference other that one is silver and the other was black.

I believe the the 30 pound disc is 6:1 and the 36-38 pound disc is 4:1.

**Goliath5.0** · 11-29-2002, 02:38 PM

When I bought my Novi 1000 kit from Jack @ Muscle Motors, he told me that the FMU that is originally supplied with the Novi 1000 kit will not work with my 30lb injectors. He said that I need to have the FMU re-calibrated. He told me that he would have to have it sent back to Paxton to have them re-calibrated it. Also that there would be a fee for such a service.

After I received my Novi 1000 kit, I had my FMU come in a day later shipped directly from Paxton, just as Jack said.

I don't believe Paxton sells a re-calibration kit for the end user to do the re-calibrating and such, but I do know that they (Paxton) will re-calibrate it for you for a price.