Howdy,
I got the 308 UC dyno'ed yesterday and I have been advised to upgrade the fuel pump as it is leaning out at high (sustained) revs. It is ok for a quick squirt but if I were to run it down the 1/4 I would have no fuel pressure at about 2/3 track.
The engine isnt a super horsepower monster as its putting out 194 hp at the wheels. There is more in it but the lack of fuel supply is holding it back.
I believe I have a standard 308 pump at the moment and I'd like to know what other people are using or recommend.
I do not want to use an electric unit for various reasons (hooking it up, noise, safety aspects etc).
Any advice would be greatly appreciated.
Cheers,
Big T
308 Mechanical Fuel Pump Recommendations?
Started by
_Big T_
, May 16 2008 02:31 PM
28 replies to this topic
#2
MRLXSS
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Posted 16 May 2008 - 03:00 PM
T,
Get yourself an L34 fuel pump. They look the same as a standard pump, but can pump up to 7psi. I bought one of these for my car off ebay amd have never had fuel pressure issues. My lil 253 pumps out 142 killer wasps, so the l34 pump should work for you to
Get yourself an L34 fuel pump. They look the same as a standard pump, but can pump up to 7psi. I bought one of these for my car off ebay amd have never had fuel pressure issues. My lil 253 pumps out 142 killer wasps, so the l34 pump should work for you to
#3
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#4
_Big T_
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Posted 16 May 2008 - 03:42 PM
Cheers, thanks man. I'll have a look and see what Ive got. Hopefully an L34 job fits my motor (VL 5 litre). I cant see any reasons why not but then again, I dont know much about these things.
Are they hard to fit up, or more to the point, is there anything I need to be careful of when doing the swap?
Cheers,
T
Are they hard to fit up, or more to the point, is there anything I need to be careful of when doing the swap?
Cheers,
T
#5
MRLXSS
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Posted 16 May 2008 - 03:55 PM
They are simple to swap over, The hardest bit for me was getting the thread on the nut to grip on the solid solid metal fuel line....
As fas as i am aware, there are no specials tricks you need to know as far as putting them in...
As fas as i am aware, there are no specials tricks you need to know as far as putting them in...
#6
TerrA LX
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Posted 16 May 2008 - 04:11 PM
It will cost more but i say go electric, you can get some quite ones and safety is not an issue if wired up with a cut out switch so its powered down if the motor stops.
#7
_Lostit_
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Posted 16 May 2008 - 04:41 PM
Check if your filters are clean , the standard mechanical one will provide more then adepaute supply .
#8
_Big T_
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Posted 16 May 2008 - 04:55 PM
^Brand new filter and the mechanic hooked up a fuel pressure guage on the pump side of the filter. Gave it a squirt on the dyno and as the revs built up to around 5500 the pressure started to drop. Guage was picking up the drop BEFORE the filter so I doubt that is the issue. Checked that the fuel lines are sufficient as well (which they are). From what I can gather a standard pump is fine for a standard engine but my engine isnt standard. I guess thats why the SLR's etc were equiped with a hi vol (L34) pump i.e standard wasnt enough?
Electric may be a better option but I really dont want to fiddle around with wiring it all up. Electronics piss me off enough already without having something else to worry about. I just want to be able to unbolt the old one and bolt on a new one.
I am a simple man
Electric may be a better option but I really dont want to fiddle around with wiring it all up. Electronics piss me off enough already without having something else to worry about. I just want to be able to unbolt the old one and bolt on a new one.
I am a simple man
#9
_Big T_
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Posted 16 May 2008 - 05:29 PM
Oops, waited too long to edit....
I wanted to add that a standard pump is okay for me at the moment. Its not until I need to hold the pedal flat for longer than 8 secs i.e drag racing that its going require an upgrade.
Cheers,
T
I wanted to add that a standard pump is okay for me at the moment. Its not until I need to hold the pedal flat for longer than 8 secs i.e drag racing that its going require an upgrade.
Cheers,
T
#10
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Posted 16 May 2008 - 05:39 PM
That's easy!Its not until I need to hold the pedal flat for longer than 8 secs i.e drag racing that its going require an upgrade.
Just set up the rest of the car to run 8's!
#11
_Big T_
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Posted 16 May 2008 - 05:57 PM
Hahaha, thats what someone at work suggested !! Or I could just run 1/8 miles like Jnr Dragsters
#12
_pallbag_
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Posted 16 May 2008 - 07:47 PM
Take it to Warwick, only an 1/8 mile track there. But you may still be running it at full revs for the full 8 secs anyways me thinks over the eigth mile !!!!
#13
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Posted 16 May 2008 - 09:41 PM
Sounds like you are using a Qjet. Problem really is in the needle and seat and float bowl size. An electric pump will fix it, I have doubts the L34 pump will.
#14
_Big T_
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Posted 16 May 2008 - 10:51 PM
Sorry Struggler, I should have mentioned I'm running an Edelbrock (525cfm). Not sure if it would be a similar problem to a QJet though?
The more I research this the more it looks like I will have to go down the Electronic path. Looks like I will have to bite the bullet and get over my electrophobia
There seems to be a few options for mech pumps on Chev engines but not much for 308's (unless I want to get an Ozrace kit but they are exy).
Time to hit the search button again and look for a quiet electronic unit.
The more I research this the more it looks like I will have to go down the Electronic path. Looks like I will have to bite the bullet and get over my electrophobia
There seems to be a few options for mech pumps on Chev engines but not much for 308's (unless I want to get an Ozrace kit but they are exy).
Time to hit the search button again and look for a quiet electronic unit.
Edited by Big T, 16 May 2008 - 10:55 PM.
#15
WhiteA9XS
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Posted 16 May 2008 - 11:03 PM
i have heard you can modify a holden v8 mechanical fuel pump by machining out the valve area and using a larger diafram ... anyone seen or done this ?
#16
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Posted 16 May 2008 - 11:08 PM
Electric pumps which rotate gears like an oil pump will generally be quieter than a diaphragm type.
Mounting and location will also play a part here.
Mounting and location will also play a part here.
#17
_Big T_
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Posted 17 May 2008 - 12:57 AM
830hp - In my searching today I found a Hi Vol Goss kit for a 308 pump. I assumed it simlpy had a bigger diaphram. I would be keen to know more about this.
ALX76 - Ive done a bit if searching and from what I can gather a Carter Black with rubber mounts might be a good, cost effective option. As I need to fit a relay to the coil to cut the pump off in case of an accident and I have a few other electrical gremlins I reckon I will just get a sparky to wire it up for me.
ALX76 - Ive done a bit if searching and from what I can gather a Carter Black with rubber mounts might be a good, cost effective option. As I need to fit a relay to the coil to cut the pump off in case of an accident and I have a few other electrical gremlins I reckon I will just get a sparky to wire it up for me.
#18
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Posted 17 May 2008 - 08:12 AM
you can buy a L34 kit for your pump for around $40 from Bursons
#19
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Posted 17 May 2008 - 10:51 AM
AFAIK the L34 kit is only a pressure increase, not a volume increase.
I have used the OZNOS setup and been very impressed with it. Yes it is expensive but it works.
As for the carter, every one I have ever used/tuned has required the use of a larger needle and seat. Adjusting the float level may also help. This won't cure the falling fuel pressure but it will help you get more than 8 sec at WOT.
I have used the OZNOS setup and been very impressed with it. Yes it is expensive but it works.
As for the carter, every one I have ever used/tuned has required the use of a larger needle and seat. Adjusting the float level may also help. This won't cure the falling fuel pressure but it will help you get more than 8 sec at WOT.
#20
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Posted 17 May 2008 - 04:27 PM
Yes Big T, unfortunately there is little in the way of mech fp options for us holden pp.
Have you used/seen the OZRACE mech pump used Struggler or are you just saying that their NOS system works?
Have you used/seen the OZRACE mech pump used Struggler or are you just saying that their NOS system works?
#21
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Posted 17 May 2008 - 07:18 PM
And remember, you what you pay for
#22
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Posted 17 May 2008 - 08:30 PM
FYI hi flow mechanical pumps usually have twin valves, so to put it into prospective, yours (if standard) will have one diaphragm with one inlet valve(coming from the tank) and one going to the carb, high flow will have one diaphragm (as per standard) with TWO valves (letting fuel inform the tank) on the inlet side and two valves on the out let side pumping fuel to the carb, all to do with flow rates and not pressure.
Anybody care to show me a holden V8 mechanical fuel pulp with twin diaphragms?
Correctly installed you will have no further problems with an electric pump.
Anybody care to show me a holden V8 mechanical fuel pulp with twin diaphragms?
Correctly installed you will have no further problems with an electric pump.
#23
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Posted 17 May 2008 - 09:59 PM
A mate i know has a 4 valve mechanical pump laying in his shed, he has had it for years. I asked him who makes it was but he didn't know, does any one know?
#24
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Posted 17 May 2008 - 10:16 PM
Mate go electric as other s have stated i have been down this road.
I am running a Holley Blue pump which comes with a regulator under $200 the wireing is not as hard as you think the pump comes with electrical drawings .
I mounted a relay in boot and main fuse close to battery .The teething problems i had was trying to run 7psi pressure by the time i got to the end of 2nd gear i was blowing 30 amp fuse .
I ran 3/8" alloy fuel line from tank to engine bay {good for 350-400hp they tell me} again easier than you might think fits in original clamps. Kept blowing fuses
I then mounted a Caterpillar 30 amp circuit breaker in place of fuse and dropped fuel pressure to 6 1/2 psi and have not had to reset it yetafter exhaustive testing.
I am running a 650 holley double pumper 4150 series with 69 jets up front and 74 jets in secondaries which drink more than me when pushed hard.
The pump copes no worries now but if i had my time over i would go a holley black pump as mine is quite noisey a mate of mine has got a holey black which is considerably quieter.
I am running a Holley Blue pump which comes with a regulator under $200 the wireing is not as hard as you think the pump comes with electrical drawings .
I mounted a relay in boot and main fuse close to battery .The teething problems i had was trying to run 7psi pressure by the time i got to the end of 2nd gear i was blowing 30 amp fuse .
I ran 3/8" alloy fuel line from tank to engine bay {good for 350-400hp they tell me} again easier than you might think fits in original clamps. Kept blowing fuses
I then mounted a Caterpillar 30 amp circuit breaker in place of fuse and dropped fuel pressure to 6 1/2 psi and have not had to reset it yetafter exhaustive testing.
I am running a 650 holley double pumper 4150 series with 69 jets up front and 74 jets in secondaries which drink more than me when pushed hard.
The pump copes no worries now but if i had my time over i would go a holley black pump as mine is quite noisey a mate of mine has got a holey black which is considerably quieter.
#25
_Bomber Watson_
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Posted 18 May 2008 - 05:50 AM
SB Chev pumps bolt onto holden sixes, not so with V8's???
I have an Endelbrock Performer mech pump on mine, flows adequately
I have an Endelbrock Performer mech pump on mine, flows adequately
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