Understanding fuel pumps and fuel maps
#1
Evolving Member
Thread Starter
Understanding fuel pumps and fuel maps
Hey all, I'm going to ask something which is probably pretty simple to understand but I'm not sure how to search for it.
I'm sending my turbo in for a rebuild/upgrade. It's going to be a 25G rebuild most likely. Factory MFI parts. The car is already setup with quite a few parts and tuned to handle them. I'm thinking about using this opportunity to install a new fuel pump and injectors.
What I can't find any information on is how fuel maps work with a fuel pump. Would putting in the higher flow pump put more fuel, or does the computer compensate for the higher flow rate and not pump as much. I'm getting it retuned regardless, but I just want to understand!
Thanks.
I'm sending my turbo in for a rebuild/upgrade. It's going to be a 25G rebuild most likely. Factory MFI parts. The car is already setup with quite a few parts and tuned to handle them. I'm thinking about using this opportunity to install a new fuel pump and injectors.
What I can't find any information on is how fuel maps work with a fuel pump. Would putting in the higher flow pump put more fuel, or does the computer compensate for the higher flow rate and not pump as much. I'm getting it retuned regardless, but I just want to understand!
Thanks.
#2
EvoM Guru
iTrader: (1)
Putting in a higher flow fuel pump only effects the tune if:
A: the old fuel pump was running out of flow, and the tuner added extra injector on time in the fuel table. A new fuel pump that has enough flow will cause a rich condition.
B: The new fule pump over runs the return system, causing a rich condition. This can usually be fixed by drilling the siphon, and/or installing an after market fuel pressure regulator.
The ECU does not automatically compensate for a fuel pump.
As long as the pump does not over run the return system, your tuner will be able to get you dialed in just fine.
A: the old fuel pump was running out of flow, and the tuner added extra injector on time in the fuel table. A new fuel pump that has enough flow will cause a rich condition.
B: The new fule pump over runs the return system, causing a rich condition. This can usually be fixed by drilling the siphon, and/or installing an after market fuel pressure regulator.
The ECU does not automatically compensate for a fuel pump.
As long as the pump does not over run the return system, your tuner will be able to get you dialed in just fine.
The following users liked this post:
h4ckluserr (Mar 9, 2016)
#3
Evolving Member
Thread Starter
So I'm going to drop in a Walbro 255(or some equivalent) with some ~1000cc injectors. Hoping that with the 25G rebuild, the new fuel stuff, and the mods in my sig, I can hit the 400HP mark. I'm getting real concerned about how much farther I want to go on stock internals.
#5
EvoM Guru
iTrader: (1)
You can make a bit over 400wtq on the stock internals and be fine with a good tune. 400whp will be no issue...
#6
Evolving Member
Thread Starter
Cool, that's good to hear. I don't think my goals are too crazy. John at Titan Motorsport is charging $600 for a tune so I want to get all the pieces ready or installed before I drop it off. I know it's a couple hundred more than most tuners, but he did it before he raised his prices and it's been solid for over 4 years now.
#7
Evolving Member
iTrader: (8)
Cool, that's good to hear. I don't think my goals are too crazy. John at Titan Motorsport is charging $600 for a tune so I want to get all the pieces ready or installed before I drop it off. I know it's a couple hundred more than most tuners, but he did it before he raised his prices and it's been solid for over 4 years now.
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#8
Evolving Member
Thread Starter
P.S. - If you haven't been through Titan before, they're an amazing shop that does amazing work.
#10
Evolving Member
Thread Starter
please please please let me know how it turns out. Your setup is almost identical to mine and I really want to see what your end result is. Are you going e85? what size injectors?
#12
Evolving Member
Thread Starter
More curiosity than anything. e-85 seems like an extra layer of complexity that I don't want to deal with. I'd much rather built for a pump 93 turn since I can get that almost anywhere in Florida.
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