Fuel pump,,,mapping ??
10 April 2012, 10:57 PM
#1
Fuel pump,,,mapping ??
Ok so we all know how important our fuel pumps are and what can obviously happen if it fails.
I'm currently using a Walbro 255 and it's getting on for 5 years old. For what a new pump costs and the potential damage I could save I'm going to be fitting a brand new pump.
Don't really want to go with a Walbro again as I've read some horror stories recently so will more than likely go to someone like RCM.
Question is,
- would I require a map tweak after fitting a new pump ?
Currently got a 255lt one but quite tempted to upgrade to a slightly larger one for safety sake.
Any ideas ?
Thanks,
Matt.
I'm currently using a Walbro 255 and it's getting on for 5 years old. For what a new pump costs and the potential damage I could save I'm going to be fitting a brand new pump.
Don't really want to go with a Walbro again as I've read some horror stories recently so will more than likely go to someone like RCM.
Question is,
- would I require a map tweak after fitting a new pump ?
Currently got a 255lt one but quite tempted to upgrade to a slightly larger one for safety sake.
Any ideas ?
Thanks,
Matt.
10 April 2012, 11:42 PM
#5
Scooby Regular
Join Date: Aug 2009
Location: St
Posts: 130
Likes: 0
Received 0 Likes
on
0 Posts
10 April 2012, 11:56 PM
#8
Scooby Regular
Join Date: Aug 2009
Location: St
Posts: 130
Likes: 0
Received 0 Likes
on
0 Posts
11 April 2012, 11:14 AM
#13
I'm not so sure about swapping fuel pumps ***** nilly without a remap tbh... As long as it's the same spec pump, it'll probably be fine, but otherwise my reasoning is as follows:
On full boost (at full chat), when you *would* get say 5 bar fuel pressure (e.g. 3.5 bar static, and 1.5 bar boost), something like a walbro 255 may not be able to keep up, so you get a gradual pressure fall off as the fuel requirement increases (higher RPM where you develop more power), so that at full chat at high revs, you may only get a fuel pressure of say 4.5 bar instead of the 5 bar you'd get if your pump could keep up.
The above condition would have been taken care of in the map, as the degradation would be gradual and probably quite consistent.
However, fit a larger capacity pump, and all of a sudden you end up with 5 bar throughout the rev range - this will mean that you end up squirting more fuel for a given injector duration, so the map will be out (on the rich side, which obviously isn't as bad as lean, but may still cause performance loss etc).
On full boost (at full chat), when you *would* get say 5 bar fuel pressure (e.g. 3.5 bar static, and 1.5 bar boost), something like a walbro 255 may not be able to keep up, so you get a gradual pressure fall off as the fuel requirement increases (higher RPM where you develop more power), so that at full chat at high revs, you may only get a fuel pressure of say 4.5 bar instead of the 5 bar you'd get if your pump could keep up.
The above condition would have been taken care of in the map, as the degradation would be gradual and probably quite consistent.
However, fit a larger capacity pump, and all of a sudden you end up with 5 bar throughout the rev range - this will mean that you end up squirting more fuel for a given injector duration, so the map will be out (on the rich side, which obviously isn't as bad as lean, but may still cause performance loss etc).
11 April 2012, 11:21 AM
#14
When I swapped out my standard pump for the Walbro 255 the ECU adjusted for the fuel difference pulling out fuel to make it run right. Was only running for a week before the remap but seemed fine.
If you have a FPR then it should be ok as said above, you can check the pressure is the same and the ECU should compensate for the slight changes.
If you have a FPR then it should be ok as said above, you can check the pressure is the same and the ECU should compensate for the slight changes.
11 April 2012, 07:09 PM
#16
Scooby Regular
Join Date: Aug 2009
Location: St
Posts: 130
Likes: 0
Received 0 Likes
on
0 Posts
I'm not so sure about swapping fuel pumps ***** nilly without a remap tbh... As long as it's the same spec pump, it'll probably be fine, but otherwise my reasoning is as follows:
On full boost (at full chat), when you *would* get say 5 bar fuel pressure (e.g. 3.5 bar static, and 1.5 bar boost), something like a walbro 255 may not be able to keep up, so you get a gradual pressure fall off as the fuel requirement increases (higher RPM where you develop more power), so that at full chat at high revs, you may only get a fuel pressure of say 4.5 bar instead of the 5 bar you'd get if your pump could keep up.
The above condition would have been taken care of in the map, as the degradation would be gradual and probably quite consistent.
However, fit a larger capacity pump, and all of a sudden you end up with 5 bar throughout the rev range - this will mean that you end up squirting more fuel for a given injector duration, so the map will be out (on the rich side, which obviously isn't as bad as lean, but may still cause performance loss etc).
On full boost (at full chat), when you *would* get say 5 bar fuel pressure (e.g. 3.5 bar static, and 1.5 bar boost), something like a walbro 255 may not be able to keep up, so you get a gradual pressure fall off as the fuel requirement increases (higher RPM where you develop more power), so that at full chat at high revs, you may only get a fuel pressure of say 4.5 bar instead of the 5 bar you'd get if your pump could keep up.
The above condition would have been taken care of in the map, as the degradation would be gradual and probably quite consistent.
However, fit a larger capacity pump, and all of a sudden you end up with 5 bar throughout the rev range - this will mean that you end up squirting more fuel for a given injector duration, so the map will be out (on the rich side, which obviously isn't as bad as lean, but may still cause performance loss etc).
Thread
Thread Starter
Forum
Replies
Last Post
Mattybr5@MB Developments
Full Cars Breaking For Spares
28
28 December 2015 11:07 PM
Mattybr5@MB Developments
Full Cars Breaking For Spares
12
18 November 2015 07:03 AM
