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Engine/Transmission (1998.5 - 2002) RASP by KO Engineering
- Thread starter prgilbert
- Start Date
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Phil, I don't consider it that tough, but everybody is different. The system consists of a fuel pump, a check valve, a bypass valve, and a hobbs switch. You need to plumb them together. The problem is that everyone likes something a little different when it comes to hoses, and that would make it tough to have a "one size fits all" hose kit. I used braided stainless, which is way over kill, and it is probably the hardest stuff to work with, but I like the looks. I have not installed a FASS, or relocated a stock lift pump, so I can not comment on how it compares to installing one of those. For me, doing the plumbing was easy, but I can't and wouldn't want to speak for others.
Paul
Turbo Tim 1
TDR MEMBER
Maybe someone could shed some light on a small concern I have and that is fuel temperature. If the RASP is pushing all kinds of fuel around what effect does it have on fuel temperature? More heat means less viscosity and lower lubricity, does this system return so much fuel to the tank that it heats it up more so than the VP does by it's self? Also what about air in the system, does the volume being pumped back to the tank / bypass create air bubbles in the system?
One of the reasons that the VP44 heats the fuel is because of the pressure it works at, and the fact it actually circulates very little fuel. The RASP is the opposite case, low pressure high volume. Very little heat is produce, and the circulation actually seems to help cool the fuel. It has been a long time since I took fluid dynamics in college ( has it really been 25 years?), and I am only user of the system, so I hope I'm explaining this correctly.
The other think that occurs to me, is that the pump is geared (actually belt driven), to be closer to the needs of the engine. It pumps lower volume at lower rpm, and higher volume at higher rpm's. This is different from a electric pump, that would have to be setup so that it pumps at least slightly more, then the max that would be needed. Because of this the amount of fuel returned to the tank at low usage points would be the greatest, and visa versa.
I am only a user of the system and not the designer. I just want to share info on a product I really like.
Paul
The other think that occurs to me, is that the pump is geared (actually belt driven), to be closer to the needs of the engine. It pumps lower volume at lower rpm, and higher volume at higher rpm's. This is different from a electric pump, that would have to be setup so that it pumps at least slightly more, then the max that would be needed. Because of this the amount of fuel returned to the tank at low usage points would be the greatest, and visa versa.
I am only a user of the system and not the designer. I just want to share info on a product I really like.
Paul
"One of the reasons that the VP44 heats the fuel is because of the pressure it works at, and the fact it actually circulates very little fuel. The RASP is the opposite case, low pressure high volume. Very little heat is produce, and the circulation actually seems to help cool the fuel. "
UMMmmm - yer mixing apples and oranges here - the volume of fuel bypassed by the VP-44 is going to be pretty much exactly the SAME with either the stock system, or the RASP setup - the VP-44 doesn't KNOW, or CARE where it's supply flow/pressure comes from, and cartainly will NOT magically start circulating more fuel and running cooler simply because a RASP pump is in there instead of a Carter!
Feel free to dazzle us with brilliance - but don't try to baffle us with BS!
UMMmmm - yer mixing apples and oranges here - the volume of fuel bypassed by the VP-44 is going to be pretty much exactly the SAME with either the stock system, or the RASP setup - the VP-44 doesn't KNOW, or CARE where it's supply flow/pressure comes from, and cartainly will NOT magically start circulating more fuel and running cooler simply because a RASP pump is in there instead of a Carter!
Feel free to dazzle us with brilliance - but don't try to baffle us with BS!
Re-read my post, and especially focus on THIS part:
"The RASP is the opposite case, low pressure high volume. "
To *me*, the inference is that the VP-44 will somehow run COOLER because of the flow characteristics of the RASP system compared to the stock setup - and THAT simply is not true!
BOTH will flow essentially the SAME thru the VP-44 - and if what I suggest is NOT what you were attempting to infer, what WERE you suggesting in the paragraph I quoted?
*I* seriously doubt that the rather trivial PSI difference between the stock LP and the RASP will have any significant difference in VP-44 heating - what do you base your assumption on?
Could it be you mistakenly typed VP-44, what you ACTUALLY meant to indicate the stock lift pump? Because, the fact IS, the VP-44 will, if supplied with relatively decent fuel supply, bypasses about 30 GPH - and that flow is primarily decreased only by the volume of flow actually CONSUMED by the engine, or in extreme cases, by restrictions in flow created by obstructions or failed lift pumps... To imply one type LP over another will somehow cause the flow-thru/bypass rate of the VP-44 to increase just ain't so!
This is very similar to the false reasoning that simply greatly enlarging fuel lines and fittings to the VP-44 will somehow cause it to provide significant power increases - not so - it will only pass a FIXED maximum amount of fuel, as long as the minimum supply needs are met, NO increase in flow thru the VP-44 will occur simply by larger lines or increased PSI to the inlet!
"The RASP is the opposite case, low pressure high volume. "
To *me*, the inference is that the VP-44 will somehow run COOLER because of the flow characteristics of the RASP system compared to the stock setup - and THAT simply is not true!
BOTH will flow essentially the SAME thru the VP-44 - and if what I suggest is NOT what you were attempting to infer, what WERE you suggesting in the paragraph I quoted?
*I* seriously doubt that the rather trivial PSI difference between the stock LP and the RASP will have any significant difference in VP-44 heating - what do you base your assumption on?
Could it be you mistakenly typed VP-44, what you ACTUALLY meant to indicate the stock lift pump? Because, the fact IS, the VP-44 will, if supplied with relatively decent fuel supply, bypasses about 30 GPH - and that flow is primarily decreased only by the volume of flow actually CONSUMED by the engine, or in extreme cases, by restrictions in flow created by obstructions or failed lift pumps... To imply one type LP over another will somehow cause the flow-thru/bypass rate of the VP-44 to increase just ain't so!
This is very similar to the false reasoning that simply greatly enlarging fuel lines and fittings to the VP-44 will somehow cause it to provide significant power increases - not so - it will only pass a FIXED maximum amount of fuel, as long as the minimum supply needs are met, NO increase in flow thru the VP-44 will occur simply by larger lines or increased PSI to the inlet!
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Well Jeeze - the STOCK LP won't "heat the fuel" like the VP-44 EITHER - they're 2 entirely different pumps for 2 different functions - I really don't understand your point, since the two pump types are pretty unrelated in basic function.
But yes, you are correct, the RASP, *or* the stock LP undoubtedly WON"T heat the fuel like the VP-44 will... But then, neither will my heater motor or windshield wipers - yeah, THEY are an apples/oranges/meaningless comparison too...
But yes, you are correct, the RASP, *or* the stock LP undoubtedly WON"T heat the fuel like the VP-44 will... But then, neither will my heater motor or windshield wipers - yeah, THEY are an apples/oranges/meaningless comparison too...
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Turbo Tim 1
TDR MEMBER
Gary I see someone wizzed in your geritol again. Look at my original question and look at Pauls answer. Then go find some information on the RASP.
It's my understanding that the RASP has it's own bypass back to the tank and that is what my question was centered around and pauls answer was for. He didn't claim the VP runs cooler with the RASP on their, the way I took it when I read it was that the Rasp doesn't flow extreme amounts through the bypass and heat fuel up. (Not the VP bypass or return).
Ease up Gary, don't slip to your ways of the past!
It's my understanding that the RASP has it's own bypass back to the tank and that is what my question was centered around and pauls answer was for. He didn't claim the VP runs cooler with the RASP on their, the way I took it when I read it was that the Rasp doesn't flow extreme amounts through the bypass and heat fuel up. (Not the VP bypass or return).
Ease up Gary, don't slip to your ways of the past!
It's my understanding that the RASP has it's own bypass back to the tank and that is what my question was centered around and pauls answer was for.
You are correct - since no quote was included in Pauls post, I didn't realize he was answering a specific question - I took his comment as a stand-alone statement, and didn't "get" what he was driving at - my fault for not reading the previous post, and my deepest apologies to Paul for "unnecessary roughness"...
BUT, I get a lot of my posts off the "last days posts", so thread continuity is not usually evident - normally its sort of a good idea to include the specific question asked in your responding post (as I am doing in THIS post) so that continuity is provided - but still my fault for not checking.
Wow Gary, How are your EGT's? Did you get twins? Water injection?
NOPE, towing a GCW of around 15,000 lbs at 1800 RPM or so puts me at about 60 MPH - and I can easily pull that in overdrive - up 7% grades, no real motivation to drop a gear and wind out the engine if there is no need - my EGT's hover right around 1100, and NEVER go above 1200 even when pressed hard. Just returned from a RV trip up into Oregon via I-5 over the range of mountains at the california/Oregon border, and those south of Ashland - easily ran those grades in OD, Comp on 3x3 at a bit over 60 MPH - those grades, and some back near Shasta must be in the vicinity of 7% - the Sierra over I-80 and hwy 50 certainly is, and I do the same there.
You are correct - since no quote was included in Pauls post, I didn't realize he was answering a specific question - I took his comment as a stand-alone statement, and didn't "get" what he was driving at - my fault for not reading the previous post, and my deepest apologies to Paul for "unnecessary roughness"...
BUT, I get a lot of my posts off the "last days posts", so thread continuity is not usually evident - normally its sort of a good idea to include the specific question asked in your responding post (as I am doing in THIS post) so that continuity is provided - but still my fault for not checking.
Wow Gary, How are your EGT's? Did you get twins? Water injection?
NOPE, towing a GCW of around 15,000 lbs at 1800 RPM or so puts me at about 60 MPH - and I can easily pull that in overdrive - up 7% grades, no real motivation to drop a gear and wind out the engine if there is no need - my EGT's hover right around 1100, and NEVER go above 1200 even when pressed hard. Just returned from a RV trip up into Oregon via I-5 over the range of mountains at the california/Oregon border, and those south of Ashland - easily ran those grades in OD, Comp on 3x3 at a bit over 60 MPH - those grades, and some back near Shasta must be in the vicinity of 7% - the Sierra over I-80 and hwy 50 certainly is, and I do the same there.
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like JR2 said a month ago
any updates ... pics
any updates ... pics
Not for a while anyhow...
The 12-valve guys are good to about 550hp or so until we need a new lift pump (or an aux. fuel system)... it'll be a while until I can afford that kind of power.
If I had an ISB - I'd bolt on this kit without even thinking twice about it.
Matt
The 12-valve guys are good to about 550hp or so until we need a new lift pump (or an aux. fuel system)... it'll be a while until I can afford that kind of power.
If I had an ISB - I'd bolt on this kit without even thinking twice about it.
Matt
Somebody has one on order now... ... ... ... ... ... ... ... ... ... .
I'm not saying names though... ... ... ... ... ... ... ... ... .
I'm not saying names though... ... ... ... ... ... ... ... ... .- Status
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