Hello everyone I have not posted in this section for quite a while.

My car quit pulling under hard acceleration, I noticed the fuel pressure dropping off from 60ish psi under boost so I put it in the shop yes unfortunately the same guy who takes forever to do anything (always has 20 to 25 corvettes around). He finally got to it and seems to think the boost a pump is bad, not raising voltage with switch jumped out.

My question is...do these fail very often? Mine is a couple years old but my car has sat a bunch in his shop for the various things I've broken . My concern is I have read lots of threads here over the years and don't remember reading about failures of these?

Should I do something different? I'm around 550Hp and may look for another 100hp out of this motor some day but not much more.


Thanks in advance you guys have always helped me out

 

I will never run or install one again. Had one first stop boosting voltage - would have cost me the engine had I not had a fuel pressure gauge, then it stopped passing voltage.

Get a Walbro 450 and be done with it.

 

I would check to make sure it isnt a wiring issue first.
A BAP certainly adds another compexity to the system and another potential failure point.
I've been running one with a stock pump for over 4 years with no issues.
That said, if I had it to do over again? I'd go with the 450 pump.

 

I agree, if the bap is in fact bad get a bigger pump and ditch it

 

Thanks for replying guys, im going to have to make this shop show me the BAP is bad and its just not a switch or wire issue. Seems there would be more negative feedback for BAP if it was a common failure.

That said willl the bigger better pump only operate on fuel pressure regulator or will it have to have some sort of boost reference switch? What is the labor like $ to install one of these pumps as I'm not going to be doing it mysel?

 

Ok too late to put bigger pump as boost a pump got ordered and installed, he never confirmed with me before hand and just did it. Funny thing is car has been there months and he could not ask me before ordering

Here is my question now..... I took car for a drive to test FP under load as he has no dyno and a road test is the only way to check it. It appears to be working properly now as FP stays around 60 psig all the way throughout rpm range. The car is still down on power however and what I've noticed is the boost is only around 8 psig at top of rpm range and feels sluggish at speed, where before it was around 12 psig and pulling strong until I get scared and back out

I realize there are lots of things that can cause this but belt was replaced and does not seem to be slipping as there was s no dust.

Could it be as simple as as the ambient air temp?, very hot and humid now.
Could it actually be a dirty air filter? Car is at shop still and I have no access at this time so I can't do much but ask here out of pure boredom.

I will answer any questions I can and appreciate any guesses in this discussion as I will probably have to tell him what to check based on feedback from here as many times before.


As usual thanks in advance for the input.



PS and yes I know I need a new shop that specializes in performance. There are some here but several hours from me. I will soon be forging a relationship with one of them as I will be adding meth soon and also looking for a few more hp's

Adam

 

Not to hijack, but tell me more about this 450 pump please.

 

Not sure if your question is directed at me but what I mean is higher volume, I don't have one but it was recommended by a couple people here. Maybe they will chime in to give more details.

 

walbro 450, very popular with people running e85 or really anyone that needs a high volume pump... they are cheap and reliable, I'm running 2 in my tank and some people run 3 or even 4 depending on how much fuel they need

 

Going from 12 to 8 lbs of boost isn't going to be from air temp and humidity alone. Your car will feel a little sluggish as you described but 4 lbs difference is a lot. I'll get a few lbs difference from a hot Florida day to the coolest we get here. Something else must be going on such as slippage, boost leak, or several other things. Your tune could be a little off too with changing the BAP. Be aware that low fuel pressure does change your air fuel ratio in the bad way under boost (good you notice the drop). If the new BAP causes higher fuel pressure than the original tune anywhere in the rpm range this will cause the car to run rich and kill power to some degree also. I bring this up because you said there was no dyno at the shop. Are you at least getting a wideband logging the A/F ratio driving around under boost?

BAP aren't the best choice in my opinion but do work. Larger pump is better IMO, they are just more costly with parts and labor combined. Price for the labor go up a lot if you have the pump that isn't accessed at the bottom rear of the drivers tank.

 

Is it plug and play like the 225/bap/hotwire kit (I happen to have all of this, but am not opposed to changing direction. Nothing is installed yet.)? If not what is required to install?

 

I don't think it will fit in the stock bucket, I have seen people modify them to fit though and it isn't very hard... I am not using the oem buckets and have my pumps mounted to a hanger... as far as wiring it's just power and ground just like the stock and 255 pump you have... so it isn't plug and play but not very hard to make them work, if you are capable of installing a stock fuel pump then you should have no problems making a 450 work in my opinion

 

Thanks for reply, the tune should be ok as the FP is back where it started, I'm not logging the afr but I do have a wideband in the car and can tell you the number is considerably lower (rich) than when it is at full boost. How long before these have to be rebuilt? I have a si v3 charger , is it possible the turbines are bent? I thought about a boost leak, I have the shop it's in now looking at the bov and other stuff but I really just need to get him to finish the stuff he is working on and take it to a real performance shop. He think it feels strong now

 

Thanks for the insight. I've been hunting around for a step by step write up on it but can't find one. I, like you, don't doubt I can do it. I'd love to know of any surprises or potential issues ahead of time though. Being prepared ahead of time always helps to shorten downtime.

 

it fits in the stock bucket, but at the same time it doesn't....

 

AFR (air fuel ratio) is what the wideband records. If you're seeing in the 14.7 range on your wideband in normal driving and a change to the 11.5 range coming into boost your good for fuel. if your getting richer than 11.5 (lower number) your leaving power on the table. Difference between 11 and 11.5 under boost is something you can feel. Your tune is most likely set up to add a certain amount of fuel at each given rpm. If you had 12lbs of boost at 6500 and now you're seeing 8 lbs at that rpm, the computer adds the same amount as before, lot less air at 8lbs so you go rich.

I'm shooting from the hip on this because I don't know your cars setup, but this is true to most.

Your blower should last a very long time before a rebuild. As long as your filter is in place no reason to have a blade issue on it. You can visually inspect them by disconnecting the intake tube.

Where in central Florida are you?

 

around Melbourne on coast and yes I believe it is rich, way more than 11 down under 9 up top, Im sure the lack of boost is what's causing both lack of power and rich condition. I'm pretty intune to my car as I drive it pretty hard and can feel when it's down in power...question is what's causing the lower boost?

 

My KB BAP went bad under normal driving with no signs at all up to that point.. Replaced it with a Vortech unit.

 

If you're off 4 lbs of boost and running around 9 for AFR that would take a huge amount of power from the car. Boost leak its the best bet. All you can do is check all the connections and as you mentioned check the BOV operation. Belt slip would be obvious by having a black powder build up. I hope you get it running back to how it should, If you where closer to Jacksonville I'd lend a hand.

Mike