Weber/Edlebrock 500 experts, IMS question....

I've heard quite a few people say that the idle mixture screws only affect the mixture at idle.

However, i'm 90% sure that when i adjust them, they affect the running of the engine in all areas. Seems to sound and perform completely different with different settings.

Can anyone give a definativ answer based on the real facts...

no but can I ask is this carb the one that good for going off road or is it the one that doent work on an incline?

also how much of a pain in the balls are you having with it as I may get one next year when I build my custom 3.5

its the holley 390 which has incline problems. Weber 500 is amazing, and there a further mod u can buy if you do have problem, which is very unlikely. Power is amazing, economy is good.

how much is it and a manifold to fit a 3.5?

how you getting on with jetting it? some of the p6 boys have spent ages ****in about with differnt jets which dont come with it trying to match it thier engines.

I'm not sure what the current price is mate.

Jetting is easy. Rpi can tell u what the correct jets and needles are for most standard engines. After that if u want to experiment the jetting kit is only cheap and u can change everything in a matter of minutes without removing the carb. Unlike the Holley which is probably a good few hours work striping it, doing the work, then rebuilding it.

Also in reality the weber is not jet fussy at all. You could take one off a 3.5 and stick it strait on a 5.0 and not notice any problems. This is because the weber work through a range of 200-500 cfm. The Holley only works at 390 cfm which is why it is really only good for bigger v8 that are working at full tilt constantly like a race engine. With the weber u can get the setup perfect for alot more of the rev range.

and the fanimould?

where did you get all your bits?

Edlebrock performer is great. Single plane so u don't need to balance the carb. Really well flowed. I swaped some bits with a mate. The edlebrock seemed alot better that the efi manifold tbh.

There's also an offy dual plane one, but this is only really nessarsery if u've got bonnet clearance issues and they don't flow as well really

let me know if you see a cheap set on the go

Will do man!

fett said:

no but can I ask is this carb the one that good for going off road or is it the one that doent work on an incline?

also how much of a pain in the balls are you having with it as I may get one next year when I build my custom 3.5

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Fett, I've got Weber 500's/Edlebrock setup on my JE Tuned 90 and after a little of this.....




It conked out due to carb float angle. Seriously I'd avoid if you want to do lots of offroading. She can be a tempemental mare if it gets too leany.

Medusa - that's a surprise. RPi recommend it for Offroad. Reckon it's brill. Is that not so?

MattMatt said:

Medusa - that's a surprise. RPi recommend it for Offroad. Reckon it's brill. Is that not so?

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Yeah I have read RPI's bumf and they may have a point about inclines and desents (going up and down) due to the float location on the webbers comparted to other similar carbs but I have had lots of occasions when traversing an incline that she coughs and splutters and if I don't clear the obstacle fast (like when your backed up waiting for those infront to pass through) she eventually conks out completely. Vacuum carbs like SU's are better off road in my experiance.

hmmm , worth thinking about , my su's are brand new too- just a pain to keep in tune but I do use the 72 off road so it might be an issue.

I dont take to much stock in what rpi say personally as they are only interesting in making a sale of there own stuff I would think.

its a tough choice as the car gets more valuable each year will I offroad it that much? hmm on street perforamce would be better and economy too, its a tough choice!

whats the hp increase? wahst the mpg increase?

if I see one cheap I may give it a try

fett said:

hmmm , worth thinking about , my su's are brand new too- just a pain to keep in tune but I do use the 72 off road so it might be an issue.

I dont take to much stock in what rpi say personally as they are only interesting in making a sale of there own stuff I would think.

its a tough choice as the car gets more valuable each year will I offroad it that much? hmm on street perforamce would be better and economy too, its a tough choice!

whats the hp increase? wahst the mpg increase?

if I see one cheap I may give it a try

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I don't know the hp figures for swapping from su's to webbers. There will be a little increase but you will suffer for that with fuel consumption. Mine does 13 - 17 mpg mostly 13 though and that's down to my enjoying the drive and noise. That's appalling and part of the reason I've bought a diesel but I will really miss the performance of the V8. I'm sorely tempted to keep her as an appreciating rare beasty I'm just arranging some indoor storage for her for the winter and I'll re-address possibly selling (but only for the right price) once JE have confirmed what spec of work has been carried out and if I happy enough with my 200tdi.

so fuel economy worse than su's?

I got a doozel trooper too as a daily hack, sad times now I am down to 2 v8's

fett said:

so fuel economy worse than su's?

I got a doozel trooper too as a daily hack, sad times now I am down to 2 v8's

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Mine's on twin SUs and got 24mpg on a run being fairly gentle and not going above 65ish.
Offroad mpg?? Don't ask
If you're that worried about fuel economy perhaps, with respect, a V8 motor is not for you??

Sent from my LT15i using Tapatalk

fett said:

so fuel economy worse than su's?

I got a doozel trooper too as a daily hack, sad times now I am down to 2 v8's

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Yeah definately worse I've considered converting to SU's but it would be a shame to after all the work that's been done before so I've just lived with it. I'd expect a standard engine to give maybe 18 to 22 on the SU's and 20 - 24 on an injection engine. A friends 90 3.9 efi returns an almost a constant 22.

Sorry Fett but I forgot to say that mines an auto so its worse!

BoomerV8 said:

Mine's on twin SUs and got 24mpg on a run being fairly gentle and not going above 65ish.
Offroad mpg?? Don't ask
If you're that worried about fuel economy perhaps, with respect, a V8 motor is not for you??

Sent from my LT15i using Tapatalk

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ive got 2 v8's mate, 3 till last month so bit late for that view

got one doozel now as said but it was for reliability rather than economy

Medusa said:

Yeah definately worse I've considered converting to SU's but it would be a shame to after all the work that's been done before so I've just lived with it. I'd expect a standard engine to give maybe 18 to 22 on the SU's and 20 - 24 on an injection engine. A friends 90 3.9 efi returns an almost a constant 22.

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thanks for the info, my 3.9 auto i just got shot of did 11 round town and 18 on the motorway at er 70ish

so no real extra power but worse mpg, but easier to set up and keep set up.

I guess it comes down to if i can find a carb and fanimould cheap enough to try