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View Full Version : rb25 10-10.5 wot afr question

davidg01234
06-11-2012, 03:46 PM
my rb25 runs good and the afr at wot is around 10-10.5 and i feel like it could be pulling much harder if it wasnt going so rich under boost. i have a walbro 255 pump, stock turbo on stock boost, freddy intake, stock tune, fmic hks ssqv bov vented into atmoshpere. i was told that the walbro pump is pumping out too much for my stock fpr to handle and i was told that if i get an adjustable fpr it would help alot. is this true?
Johnphen
06-11-2012, 03:50 PM
what is the pressure at now in the rail? or do you not know?

if you don't know, setting a static pressure would be a good idea. helps you get consistent readings, dial in the afr a bit, and also prevents fouled plugs / rich idle
waxball88
06-11-2012, 03:52 PM
Boost leak would be the most obvious cause. And should be the first thing you check before pissing time away changing shit.
davidg01234
06-11-2012, 03:55 PM
what is the pressure at now in the rail? or do you not know?

if you don't know, setting a static pressure would be a good idea. helps you get consistent readings, dial in the afr a bit, and also prevents fouled plugs / rich idle
my pressure is at 34psi with vac, 42 without vac connected
davidg01234
06-11-2012, 03:59 PM
Boost leak would be the most obvious cause. And should be the first thing you check before pissing time away changing shit.

no boost leaks at all. already checked yesterday. also the boost/vacuum gauge is showing plenty of vacuum
Johnphen
06-11-2012, 04:04 PM
well the pressure isn't KILLING you... but a FPR would help..

I guess a better question is, how much timing do you have at full boost under WOT?
davidg01234
06-11-2012, 04:08 PM
well the pressure isn't KILLING you... but a FPR would help..

I guess a better question is, how much timing do you have at full boost under WOT?

ha ya dont get me wrong that 1st gear pull is still pretty strong but i still feel like im losing some power. how would i know that? the timing is set at 15 where it should be?
is it possible that under boost my fuel pump is putting out too much for the stock fpr causing it too go that rich??
Johnphen
06-11-2012, 04:09 PM
ha ya dont get me wrong that 1st gear pull is still pretty strong but i still feel like im losing some power. how would i know that? the timing is set at 15 where it should be?
is it possible that under boost my fuel pump is putting out too much for the stock fpr causing it too go that rich??

not base ignition timing, the timing at full boost under WOT?

What are you using to datalog?
davidg01234
06-11-2012, 04:11 PM
not base ignition timing, the timing at full boost under WOT?

What are you using to datalog?

im not this is justa stock build with a few bolt ons nothing huge
Johnphen
06-11-2012, 04:15 PM
you need to find a way to datalog your RB if you want to see if you are losing any power, sounds like the next steps to me since you dont have any vac issues and your afr's seem consistent.

power FC and FC Edit ftw.
davidg01234
06-11-2012, 04:19 PM
you need to find a way to datalog your RB if you want to see if you are losing any power, sounds like the next steps to me since you dont have any vac issues and your afr's seem consistent.

power FC and FC Edit ftw.

ya that would be nice if i could find about a grand lol
fliprayzin240sx
06-11-2012, 04:56 PM
not base ignition timing, the timing at full boost under WOT?

What are you using to datalog?

Why would his timing at WOT make a difference? He's running a stock ECU and his timing map will be the stock timing map. Then again, OP, did you crack the ECU open to see its not a modded ECU?
davidg01234
06-11-2012, 05:02 PM
Why would his timing at WOT make a difference? He's running a stock ECU and his timing map will be the stock timing map. Then again, OP, did you crack the ECU open to see its not a modded ECU?

Ya its a stock ecu for sure. I think I'm gonna try putting an adjustable fpr on. I'll need it eventually anyways when I start doing more Modding. Can anyone recommend a good fpr?
Johnphen
06-11-2012, 07:16 PM
Why would his timing at WOT make a difference?

OP says he's losing power, knock modifies ignition which would in turn result in a loss of power. Pretty elementary actually.

The mere fact you are asking that question casts serious doubt on the worthiness of your input in this thread.

He's running a stock ECU and his timing map will be the stock timing map.

And that automatically means his ignition is the same at WOT and full boost no matter what the knock sensors or ecu say right?

:picardfp:
Johnphen
06-11-2012, 07:22 PM
Ya its a stock ecu for sure. I think I'm gonna try putting an adjustable fpr on. I'll need it eventually anyways when I start doing more Modding. Can anyone recommend a good fpr?

I like the aeromotive drag 13109, there's a ton of options all pretty good.

Jesse’s RB25 S13 – Installing Top Feed Injectors | StockSpyder (http://stockspyder.com/2011/12/09/jesses-rb25-s13-installing-top-feed-injectors/)

for fitting info or AN conversion info.
davidg01234
06-11-2012, 10:40 PM
I like the aeromotive drag 13109, there's a ton of options all pretty good.

Jesse’s RB25 S13 – Installing Top Feed Injectors | StockSpyder (http://stockspyder.com/2011/12/09/jesses-rb25-s13-installing-top-feed-injectors/)

for fitting info or AN conversion info.

Nice. What's another good one? I'm liking the nismo and it seems to be pretty common but its kinda pricey