I've just bought a 3 port boost solenoid and a 340lph fuel pump for my blob Sti. I'm planning on getting it mapped around March/April time but want some mods done first. Would I be okay to fit these now or will they need fitting at the time
Of the mapping? Car currently has walbro 255 and 2 port. I don't think it has ever had a map before. Thanks

 

I would wait until closer to the time.
If the car already has a 255 on it, you won't gain anything from fitting either of these until you have it mapped.
You could probably fit the 340 pump without a map, but is there any reason you need to fit it at all? - the reason I ask is that if you have no other assisting mods you won't need one with that output - the 255 will be perfectly sufficient - I know first hand of 2 owners that have run 255 pumps with 400+ bhp for several years with no ill effect, although that's probably pushing them to the limit , but for 300-350 it's fine.

I have a 340 on mine now but was running a 290 previously and mine is fairly modded.

The 3 port your mapper will fit at the time of mapping, it's a simple one.

 

Only changing as read there on the limit at around 370 and I'm planning on going beyond that. The 255 was on the car when I got it so unsure of its condition etc. wanting to get the mods to support higher bhp so not buying twice if that makes sense

 

Fair enough, although not sure I'd agree with the "on the limit" comment at that level unless you're screaming the **** out of it round a track
Just change the pump prior to the map then and have your mapper fit the 3 port.

You're best off spending the money on a decent exhaust system and panel filter to start with, that should net you between 320 and 330bhp on the standard turbo, maybe 350 if you're lucky and your TMIC and other supporting anciliaries are in good nick.
TBH if you don't have that yet I would hold off on going for a map as you'll probably see no power gain at all just by fitting the other 2 mods, and if the car is running okay at present chances are the pump is absolutely fine.

 

thanks. Will do that. I think it was somewhere on here I read it.

 

When I fitted my 255 pump in place of the original the ECU had to pull as much as it could to fuel correct for the pump over the standard unit. I'd be a little wary about going up to the 370 for that length of time without a map adjust. Wait and fit closer to the time IMO.

 

Okay thanks, wasn't sure if it was set to supply fuel for what the ecu asks for.

 

ECU will fuel correct to a certain extent, mine was certainly on the limit of its capability when I upgraded.