I'm planning to run E85 on my turbo B18C-R setup and my tuner recommended that I go with a Walbro 450 fuel pump (I'm currently running Walbro 255). I'm curious though, when the time comes for me to go back to stock (I live in Cali and I go back to stock for smog... I know.... it's a PITA) would be safe to run a large fuel pump on stock injectors (240cc)? I will be on stock motor, ECU, catalytic converter, etc but If I can avoid reverting one less thing for smog purposes then that would be great.

Any information would be greatly appreciated! Thanks in advance HT Community!



PS. Not looking for answers that include hot smogs or moving to a different state.

 

Should be fine as long as the stock fuel pressure regulator does its job. If not swapping the pump back is a pretty quick job also.

 

Like the above said, you'll be fine as long as the stock fpr does it's job. The issue is, I personally don't think they're built well enough to handle that. I think they're only made to manage the psi coming out of a stock pump. As far as I know, aftermarket fprs aren't against smog, as long as it's set to the stock pressure. So run it with the stock fpr and measure the pressure you're getting. If it's still high, then get an aftermarket upgrade and set it to the stock psi.

 

Higher output fuel pumps move significantly more fuel volume than a stock pump... and since the stock fuel lines are small, it is likely that your line pressures will increase. It has NOTHING to do with the stock FPR, other than the discharge opening is small, so a limited amount of fuel can pass through and that means that more fuel pressure builds up in front of it inside the fuel rail.
I cannot answer the FPR smog questions... this is the stuff that should be discussed with a BAR Ref.

 

Thanks for chiming in guys.

I should be clear that I'm more concerned about running lean than smog issues. I was told that I would run lean if I ran a Walbro 450 fp on stock 240cc injectors so I wanted to see if there was some truth to this. I thought injectors can only spray "x" amount of fuel (in my case.. 240 cc a minute)... so can a big fuel pump actually push the stock injectors to spray more fuel than advertised? I'm just trying to avoid changing out one less thing when going back to "stock".

I appreicate the feedback!

 

A big fuel pump doesn't change the duration of the injector pulse... but it does raise fuel pressure simply by forcing more fuel volume through the factory fuel lines than the OE pump did and this raises fuel pressure, thus, pushing more fuel volume through the fuel injector during the injector pulse period.

The engine will NOT be leaner... so there is no cause for concern on that front.