64 replies to this topic

[DarkHand]

what difference would and electric pump and a FPR make?

It depends on whether the stock pump starves the carb of fuel or not.

Warning: Assumptions ahead! I could be totally wrong on everything I say.

Lots of people concentrate on fuel pressure when it comes to carbs, even the muscle car guys, and that's always made me wonder. The float works exactly like a toilet tank... the engine pulls fuel from the bowl with vacuum, and the level of fuel in the bowl drops. The float drops with it, opening the needle, which lets more fuel in. When the float goes up again, it closes the needle, and fuel stops entering the bowl, and the bowl is kept full.

Adjusting the fuel pressure just adjusts the pressure that the fuel is shooting into the bowl; it doesn't change fuel delivery to the engine as it would on an injected setup. If you sat on the engine during a race and poured fuel into the bowl with a pitcher, you should be making the same amount of power as with the float working properly, all things being equal. So provided the float bowl stays topped up at all loads/RPMs, I can't see how pressure can have an impact on performance.

Perhaps the fuss about pressure is in fact to keep the float bowl topped up. If the bowl runs dry at any time, you'll definitely see a problem with performance. Increasing the pressure is technically a way to fix the problem, but fuel pressure in this case is more an indicator of fuel volume; more pressure will push more volume, but it's the volume of fuel being delivered to the bowl you're actually concerned about.

So I guess what I'm trying to say is that I don't know what I'm trying to say , but fuel pressure is a different thing when comparing carbed cars to injected cars.

[86rustbox]

The p29's do come with reliefs already cut (for a dohc 16v head) but who can say how that will fare with a different cam somewhere down the road... just saying for future reference

yeah, i guess i'll have to cross that bridge when i come to it. most likely i'll plastigage it when i chose to change cams.

thanks for the helpful links, zak.

[zakats]

Darkhand is a smart guy and is making a good point... what I'm going off of with the raise in fuel pressure is the same concept as, for example, Eldo with his turbo carb setup that he successfully ran with a RRFPR+electric pump...
I'm not sure exactly what will need to be done in order to make it work perfectly but I know that it will with minimal work and almost/no $ investment on the carb.

[86rustbox]

It depends on whether the stock pump starves the carb of fuel or not.

Warning: Assumptions ahead! I could be totally wrong on everything I say.

Lots of people concentrate on fuel pressure when it comes to carbs, even the muscle car guys, and that's always made me wonder. The float works exactly like a toilet tank... the engine pulls fuel from the bowl with vacuum, and the level of fuel in the bowl drops. The float drops with it, opening the needle, which lets more fuel in. When the float goes up again, it closes the needle, and fuel stops entering the bowl, and the bowl is kept full.

Adjusting the fuel pressure just adjusts the pressure that the fuel is shooting into the bowl; it doesn't change fuel delivery to the engine as it would on an injected setup. If you sat on the engine during a race and poured fuel into the bowl with a pitcher, you should be making the same amount of power as with the float working properly, all things being equal. So provided the float bowl stays topped up at all loads/RPMs, I can't see how pressure can have an impact on performance.

Perhaps the fuss about pressure is in fact to keep the float bowl topped up. If the bowl runs dry at any time, you'll definitely see a problem with performance. Increasing the pressure is technically a way to fix the problem, but fuel pressure in this case is more an indicator of fuel volume; more pressure will push more volume, but it's the volume of fuel being delivered to the bowl you're actually concerned about.

So I guess what I'm trying to say is that I don't know what I'm trying to say , but fuel pressure is a different thing when comparing carbed cars to injected cars.

darkhand, i didn't even see your reply when i made mine...it must have been on the next page. that makes sense about the electric pump, i didn't think it could let any more fuel in than the needle valve allowed. i have a bit of fuel starving problems, its this slight directional problem with the float: when making long hard lefts it is slightly starved, long hard rights are slightly rich. could that be fixed by an elec pump and FPR?

darkhand, what's your take on the e85? do you think i'll need more fuel delivered along with compression increase? (i.e. drilling jets, richening idle mix)

Edited by 86rustbox, 12 August 2009 - 10:06 AM.

[zakats]

could that be fixed by an elec pump and FPR?

I doubt it, I think that has more to do with your tank/pickup/baffling since the stock mechanical pump ought to be supplying enough fuel through the turns as long as it sees enough supply. This issue is well known for our cars and requires some inconvenient changes- Easiest would be just running the car with more fuel, second simplest would probably be a dual pump setup with a surge tank- after that all the options involve replacing or modifying the stock tank.

[DarkHand]

Ya the turning issue is well known, that's a pickup issue. If it were the carb, a long hard right would go lean since that's when fuel gets pulled away from the inlets at the bottom of the float bowl.

Can't say much about the E85 issue since I'm not that familiar with it, but wikipedia seems to back up the idea of needing more fuel at least:

Using E85 in a gasoline engine has the drawback of achieving lower fuel economy as more fuel is needed per unit air (stoichiometric fuel ratio) to run the engine in comparison with gasoline.

http://en.wikipedia....tandard_engines

[kaymo]

i had to make a comment about the "greener racing"

e85 is in no way better for the environment, or the economy for that matter. its a terrible idea and should be shut down.

it takes MORE REGULAR FUEL to PRODUCE the e85! it also raises the hell out of our food prices! it kills our fuel economy and it helps destroy our older cars that weren't designed for it!

and whoever said that our fuel has been 10% ethanol since the 70's, i need to see some evidence on that one. there are many gas stations that i used to go to that have only recently switched to 10% ethanol, and only since the majority of these stations have switched have i heard complaints about fuel economy, power loss, and fuel system break down. fuel pumps are going out left and right on people, even in newer cars. they say you cant run e85 in normal cars because it will destroy seals and eat fuel pumps. so why isnt 10% ethanol bad for our cars? the fact is, it IS bad for our cars. they are TRYING to get our old vehicles off the road. i understand getting rid of leaded fuel, but this is sabotage.

back to greener- fill up an SUV with e85. you just used the amount of corn an average person eats in ONE YEAR. that just a PERSON. imagine how much ANIMAL FEED that is! and since the demand goes up for corn, the price goes up. now it costs more to feed the animals we eat. we just raised the price of ALL FOOD because we thought it would be smarter to run our cars on corn......

what is used to harvest this corn? diesel tractors! for every gallon of ethanol produced, we use 1.3 gallons of fuel. that isnt just a number pulled from my head (altho i am remembering from an article from a while back) but it is about that ratio.

so if it costs more, makes less power, and takes twice as much fuel, why are they pushing it on us? why is it cheaper to buy?

our government helps this problem along (as it does most problems) by adding tax breaks for e85. this makes it cheaper, therefore more enticing to us. they offer tax breaks for flex fuel cars to further assist this plan. then the gas companies switch to 10% ethanol under the guise that its more environmentally friendly, when in reality its only because ITS been made CHEAPER. its a FILLER. i had a gas station employee tell me that the ONLY reason they recently switched to 10% was because of the price increase in fuel, and the owner decided to save some money and go 10%.
now that everyone has 10% gas in their older cars, they are having to refuel more often and their cars are breaking down more frequently! after we dump our money into fixing our old car that we end up having to junk anyway, the only thing we can afford to get is the car with all the tax breaks... the flex fuel car that started this bullshit in the first place!


PLEASE reconsider doing this. i understand its cheaper... and looks real enticing, but its helping destroy old cars and its not really making any real effect on the amount of oil WE STILL BUY FROM OTHER COUNTRIES!!!


ethanol has been around forever, if it were so great as a fuel, why did we not start there? why have we not gone there before? POLITICS AND GREED. they were never so rampant until today....

[zakats]

back on the topic of pistons, be sure to read JSGprod's post in this thread: http://www.redpepper...e...c=44760&hl=

[86rustbox]

i had to make a comment about the "greener racing"

e85 is in no way better for the environment, or the economy for that matter. its a terrible idea and should be shut down.

it takes MORE REGULAR FUEL to PRODUCE the e85! it also raises the hell out of our food prices! it kills our fuel economy and it helps destroy our older cars that weren't designed for it!

and whoever said that our fuel has been 10% ethanol since the 70's, i need to see some evidence on that one. there are many gas stations that i used to go to that have only recently switched to 10% ethanol, and only since the majority of these stations have switched have i heard complaints about fuel economy, power loss, and fuel system break down. fuel pumps are going out left and right on people, even in newer cars. they say you cant run e85 in normal cars because it will destroy seals and eat fuel pumps. so why isnt 10% ethanol bad for our cars? the fact is, it IS bad for our cars. they are TRYING to get our old vehicles off the road. i understand getting rid of leaded fuel, but this is sabotage.

back to greener- fill up an SUV with e85. you just used the amount of corn an average person eats in ONE YEAR. that just a PERSON. imagine how much ANIMAL FEED that is! and since the demand goes up for corn, the price goes up. now it costs more to feed the animals we eat. we just raised the price of ALL FOOD because we thought it would be smarter to run our cars on corn......

what is used to harvest this corn? diesel tractors! for every gallon of ethanol produced, we use 1.3 gallons of fuel. that isnt just a number pulled from my head (altho i am remembering from an article from a while back) but it is about that ratio.

so if it costs more, makes less power, and takes twice as much fuel, why are they pushing it on us? why is it cheaper to buy?

our government helps this problem along (as it does most problems) by adding tax breaks for e85. this makes it cheaper, therefore more enticing to us. they offer tax breaks for flex fuel cars to further assist this plan. then the gas companies switch to 10% ethanol under the guise that its more environmentally friendly, when in reality its only because ITS been made CHEAPER. its a FILLER. i had a gas station employee tell me that the ONLY reason they recently switched to 10% was because of the price increase in fuel, and the owner decided to save some money and go 10%.
now that everyone has 10% gas in their older cars, they are having to refuel more often and their cars are breaking down more frequently! after we dump our money into fixing our old car that we end up having to junk anyway, the only thing we can afford to get is the car with all the tax breaks... the flex fuel car that started this bullshit in the first place!


PLEASE reconsider doing this. i understand its cheaper... and looks real enticing, but its helping destroy old cars and its not really making any real effect on the amount of oil WE STILL BUY FROM OTHER COUNTRIES!!!


ethanol has been around forever, if it were so great as a fuel, why did we not start there? why have we not gone there before? POLITICS AND GREED. they were never so rampant until today....

i'm sure we could all type that much about our opinions of e85 and food/fuel debate, but THAT'S NOT WHY I STARTED THIS THREAD. i wanted to know everyone's take on the effects on performance and the adaptability of engines...which i see somewhere in there you clearly stated that you believe it's bad for them. thanks for your input on that.

once again if you'd like to have this debate, please start another thread on it in off-topic where it belongs. to put it in perspective, i've read all the research that backs up your perspective as well as mine. i've found equal criticisms of both and formed my opinions.

thanks for the link on the pistons, zak. so maybe p29's will be okay with a stock cam? jay said they needed to be hand cut for high lift cams.

Edited by 86rustbox, 12 August 2009 - 10:49 PM.

[kaymo]

well excuuuuuse me. lol didnt mean to muddle up your thread, i kinda thought it was on topic. seems kinda silly starting another OT thread about it, to me would make it seem like im trying to say your idea is stupid without directly replying to you, KNAWMEEN? and that wasnt my goal.

im glad you have done the research on that it,again i did not know. but if you did then you'd know that you probably would need a custom rebuild kit for the carb to not turn into a gasoline fountain, after it eats the float and uses it to clog your jets....


and its more than just food/fuel. its a freakin conspiracy man! you gotta fight the power!

man it must really get on yall's nerves that i type 120wpm lol

[86rustbox]

well excuuuuuse me. lol didnt mean to muddle up your thread, i kinda thought it was on topic. seems kinda silly starting another OT thread about it, to me would make it seem like im trying to say your idea is stupid without directly replying to you, KNAWMEEN? and that wasnt my goal.

im glad you have done the research on that it,again i did not know. but if you did then you'd know that you probably would need a custom rebuild kit for the carb to not turn into a gasoline fountain, after it eats the float and uses it to clog your jets....


and its more than just food/fuel. its a freakin conspiracy man! you gotta fight the power!

man it must really get on yall's nerves that i type 120wpm lol

you do type a lot kaymo...lol. if another thread was started i can see how it might seem like you were saying my idea was stupid w/o actually replying. probably should just happen here...but i was hoping it wouldn't, i just want to know about the mechanics of it. thanks for your input on the carb deterioration. i've heard this about the whole fuel system, but i've used a 50/50 mix in a couple of FI cars and had no problem. have you had your carb eaten up by e85?

and ethanol being a conspiracy is a matter of opinion, dude. i think the oil co's are conspiring a to a heavier degree.

i went ahead and drilled my jets today. i've been reading up on some of these drag racing sites and forums and everyone running edels and holleys say you need more fuel. much different carbs i know, but the process of introducing fuel is relatively the same. e85 kits for them come with larger jets/powervalve and stainless steel needles. i drilled the "115" jet from .043" to .047" and the "60" jet from .028" to .032". i didn't touch the idle jet because first of all i wasn't sure which one was idle and which one was 3rd bbl, and second because i think it might not need it. i'll try a tweek in mix and see if i can get it to idle right.

i'll keep ya'll updated whenever i put it on (have to put exhaust back on first...i like my eardrums) and get some ethanol moving through. and yes, kaymo i'll give you props if it does eat my float.

[kaymo]

no i only want props when you discover you're using twice as much gas that only is a tad cheaper

jk id like it to work great for you but it just sounds like a good way to kill a carb they're bad enough at going bad when you look at them funny...


btw did you know scientists are working at bioengineering microbes that eat algae and shit gasoline i cant wait to have my own algae farm

[86rustbox]

no i only want props when you discover you're using twice as much gas that only is a tad cheaper

jk id like it to work great for you but it just sounds like a good way to kill a carb they're bad enough at going bad when you look at them funny...


btw did you know scientists are working at bioengineering microbes that eat algae and shit gasoline i cant wait to have my own algae farm

well, we'll see. i have to get my exhaust straightened out and i'll be running it soon.

i haven't heard bout the algae. i have heard of making ethanol from shit though. called cellulosic ethanol i think. supposed to be much more efficient to make than corn but you know there's no money in shit.

congrats on running e85 for three seasons, TJ. what kind of gas mileage do you get versus gasoline? did you have to do a lot of tuning on the air fuel ratio (other than for the supercharger)?