Car loosing power at high PRM in 3rd gear

second: you rip through it somewhat slower since the gears are higher (numerically lower).

I was talking about the gear ratio here. Am I right in what I was saying? Maybe the terms I should have used were "less steep"..which is numerically lower.......eh, I'm tired, and learning

newho, agreed. It could be the start of an ignition problem...a VERY early start at that cuz from what I've read they just go out once someone gets to a certain rpm
 
cbarr300 said:
if I'm not mistaken the car's seeing more load and needs more fuel. Maybe, just maybe, ur pump can hold up pretty good in first and second...but once u get to top end on third it just can't supply the fuel u need. Maybe u could get a fuel pressure gauge off a buddy and run it in the car just for diagnostic purposes

luck

Gotta go quickly and don't have time to read the whole thread :nono:

but

BINGO :banana: GIVE THIS MAN A CIGAR :rlaugh:

To me ... prob sounds fuel related :)

Grady
 
I'll take my cigar now...or a cookie, whichever. :rlaugh:

my fuel pump is starting to go on its way out as well...though I don't have any performance problems yet. Been getting realllly loud lately and taking a about 3 seconds to start building pressure when hot. At least the one I have now is inline so all I gotta do is take the old one out and put the new one in.

You could also get a wideband. Again, something u'll want with nitrous....those can get expensive though

luck
 
but the rpms happen slower higher in 3rd, thus giving the pump more time to make more pressure or keep up. Now im just thinking to my logic. But i have clue of how it really works

the rpms do happen slower in third and you are running higher rpms longer...so ur correct about that.

now onto the pump. It's not really about the pump keeping up with how FAST it revs. Its mainly about putting the volume out for as long as it needs to put it out. Since you're at higher rpms longer in third, the pump has to constantly flow a HUGE volume of fuel. If the pump is on its way out...it just can't flow that huge volume of fuel for as long as it needs to.

It may be able to hold up for a little while in the higher rpms, but it seems that his pump just can't hold up for the amount of time he's at the top end of third. My bet is that if he was to floor it in fourth gear he'd be having problems at a bit lower of an rpm since it accelerates even slower in fourth and requires even more fuel to overcome wind resistance, drag, etc.....that'd be at a rather dangerous speed though.

Just trying to help you see what's going on. Hope I didn't make things more confusing for you....I have a habit of doing that lol.

someone feel free to chime in if my logic seems a bit wrong
 
cbarr300 said:
the rpms do happen slower in third and you are running higher rpms longer...so ur correct about that.

now onto the pump. It's not really about the pump keeping up with how FAST it revs. Its mainly about putting the volume out for as long as it needs to put it out. Since you're at higher rpms longer in third, the pump has to constantly flow a HUGE volume of fuel. If the pump is on its way out...it just can't flow that huge volume of fuel for as long as it needs to.

It may be able to hold up for a little while in the higher rpms, but it seems that his pump just can't hold up for the amount of time he's at the top end of third. My bet is that if he was to floor it in fourth gear he'd be having problems at a bit lower of an rpm since it accelerates even slower in fourth and requires even more fuel to overcome wind resistance, drag, etc.....that'd be at a rather dangerous speed though.

Just trying to help you see what's going on. Hope I didn't make things more confusing for you....I have a habit of doing that lol.

someone feel free to chime in if my logic seems a bit wrong


Your logic looks OK to me Clay :nice:

Its all about the volume ... don't ya see :D

Many focus on the pressure ... but that'll be a future thread :rlaugh:

Things happen very fast in the lower gears ... no doubt about it!

They happen so fast the prob does not have time to develop ;)

This reminds me of a similar low/high gear thing and I'm gonna post up a new thread in talk so I don't hijack this thread.

Bye Now :)

Grady
 
sage2k said:
i thought our fuel pumps flow max volume, thats why we have return style setup?

Think about the 5/8" garden hose story that has been around for years.

You want more water so you turn up the pressure.

You can only go so far with pressure to get more water.

Sooner or later, you gotta move up to the 3/4" size for more volume.

With the larger size hose, you get more capability for volume. More pressure is now effective where as with the smaller size hose, it just could not allow enough volume for more pressure to supply more water.

Grady