minorv8
My 500 carb seemed to run best on the stock setting. 86jets 065x052 rods with the accelerator pump on the middle hole.
How does that sound compared to yours?
Rolling road booked for Thursday.
Edelbrock 600 on a 4.6
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I had a .86 jet, 6755 rod and .95 secondary jet. It ran just about perfectly apart from rich mixture at full throttle.
I bought an 1 in thich Edelbrock phenolic spacer with 4 holes, logic being twofold, to isolate the heat from the carb (not that there were any big issues with vaporisation) and getting more volume to the intake. I have the performer dual plane intake which I think may be a bit too small for a 4,6. Since the carb was out I also fitted smaller .92 secondary jets.
This setup caused a momentary lean spot at mid range that I mentioned. I don´t know whether this is due to the spacer or smaller sec jet. I fitted a 6852 rods and this just about eliminated the lean spot, I need to fit another pair of step up springs to check it this eliminates the problem. If it does not help, I´ll put the .95 jets back in.
There is not a big difference between 68 and 67 cruise ratios, they are around 13,5-14:1. It does feel a bit better with 65 but fuel economy suffers.
500 carb is more than enough for a 4,6 engine, but US test have shown that "too" big carb may not be that bad after all. Off idle throttle response may suffer with 600 carb but since the primary throttles are the same size as 500 it may not be that big an issue. Holley would be another story though.
Wideband lambda is a very valuable tool for setting and definitely worth buying. Rolling road setup is a good thing but it cannot replicate the actual driving conditions. One often needs to fine tune but it is easy when you are in the ball park. I have Innovate LC-1 with XD-16 gauge. Only problem with it is that I get E-8 error code (which I need to address...) But that is another story.
I bought an 1 in thich Edelbrock phenolic spacer with 4 holes, logic being twofold, to isolate the heat from the carb (not that there were any big issues with vaporisation) and getting more volume to the intake. I have the performer dual plane intake which I think may be a bit too small for a 4,6. Since the carb was out I also fitted smaller .92 secondary jets.
This setup caused a momentary lean spot at mid range that I mentioned. I don´t know whether this is due to the spacer or smaller sec jet. I fitted a 6852 rods and this just about eliminated the lean spot, I need to fit another pair of step up springs to check it this eliminates the problem. If it does not help, I´ll put the .95 jets back in.
There is not a big difference between 68 and 67 cruise ratios, they are around 13,5-14:1. It does feel a bit better with 65 but fuel economy suffers.
500 carb is more than enough for a 4,6 engine, but US test have shown that "too" big carb may not be that bad after all. Off idle throttle response may suffer with 600 carb but since the primary throttles are the same size as 500 it may not be that big an issue. Holley would be another story though.
Wideband lambda is a very valuable tool for setting and definitely worth buying. Rolling road setup is a good thing but it cannot replicate the actual driving conditions. One often needs to fine tune but it is easy when you are in the ball park. I have Innovate LC-1 with XD-16 gauge. Only problem with it is that I get E-8 error code (which I need to address...) But that is another story.
Well thats very interesting because your 500 setup is slightly leaner than mine was, which sureley must indicate a problem with my AFR numbers.
I too am using the performer inlet which is port matched to the heads.
Im using 098jets and 068x052 rods in the 600 now.
Went for another drive last night. One area in which the 600 is better is when say cruising in 4th gear at 60mph if I suddenly floor it, the engine response is instant a marked improvement on the 500.
But having said that at 30mph in 5th gear the pickup when accelerating gently is not as good.
To be honest I think the 500 is the right choice for a road car.
Hoping the 600 will be better when driven hard. (which I just cant do on the road without losing my license).
Mark
I too am using the performer inlet which is port matched to the heads.
Im using 098jets and 068x052 rods in the 600 now.
Went for another drive last night. One area in which the 600 is better is when say cruising in 4th gear at 60mph if I suddenly floor it, the engine response is instant a marked improvement on the 500.
But having said that at 30mph in 5th gear the pickup when accelerating gently is not as good.
To be honest I think the 500 is the right choice for a road car.
Hoping the 600 will be better when driven hard. (which I just cant do on the road without losing my license).
Mark
30 mph in 5th gear with a four barrel carb, and asking the poor thing to accelerate on the throttle! 
You don't ask much of it do you 
I would think a fully mapped fuel and spark set up would have a job dealing with that, even a 3d mapped set up. 1100 -1200 revs, one pulse from each cylinder every 10th of a second split across 2 carb barrels (secondarys closed) not easy for a carb to get a steady state flow so you are relying very much on the transition enrichment as you open the throttle, and I presume you have a electro-mechanical distributer (not mapped ignition) . Personally I would be very happy with what it is doing, it sounds like you have a d*mn good set up to me the fact it doesn't bog out completly makes me think it is pretty close:shock:. These are fixed choke carbs remember not the good old SU with a variable venturi, even with two venturies to each set of four cylinders you are asking the primarys to meter 14 to 1 fuel ratio acuratly over at least two doublings in air flow volume, cope with the transition onto secondatys and deal with all part and intermediate throttle settings and accuratly meter as you open the throttle.
Sorry didn't mean to have this turn into a rant, just want you to think about what you have already achieved, one hell of alot in my book:D
Best regards
Mike
You don't ask much of it do you I would think a fully mapped fuel and spark set up would have a job dealing with that, even a 3d mapped set up. 1100 -1200 revs, one pulse from each cylinder every 10th of a second split across 2 carb barrels (secondarys closed) not easy for a carb to get a steady state flow so you are relying very much on the transition enrichment as you open the throttle, and I presume you have a electro-mechanical distributer (not mapped ignition) . Personally I would be very happy with what it is doing, it sounds like you have a d*mn good set up to me the fact it doesn't bog out completly makes me think it is pretty close:shock:. These are fixed choke carbs remember not the good old SU with a variable venturi, even with two venturies to each set of four cylinders you are asking the primarys to meter 14 to 1 fuel ratio acuratly over at least two doublings in air flow volume, cope with the transition onto secondatys and deal with all part and intermediate throttle settings and accuratly meter as you open the throttle.Sorry didn't mean to have this turn into a rant, just want you to think about what you have already achieved, one hell of alot in my book:D
Best regards
Mike
poppet valves rule!
My engine pulls cleanly from about 900-1000 rpm at 5th gear. I used to have a Holley 390 but IMO Edelbrock is a lot better especially at low revs. As for drivability, (especially with a cold engine) fixed choke is a lot better than the SU setup I have.
mgbloke, like I said your air/fuel ratio figures cannot be accurate since you simply can´t get those hp/torque figures with engine that lean. I don´t have any underbonnet clearance issues (a Moggy) so I have that 1 in. spacer plus 4 in tall air cleaner. I also have a stub stack fitted on on the carb which seems to help the flow quite a bit.
mgbloke, like I said your air/fuel ratio figures cannot be accurate since you simply can´t get those hp/torque figures with engine that lean. I don´t have any underbonnet clearance issues (a Moggy) so I have that 1 in. spacer plus 4 in tall air cleaner. I also have a stub stack fitted on on the carb which seems to help the flow quite a bit.
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jefferybond
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Lambda sensors need to be very hot to work properly, which is why they are normally installed in the headers or collector. Shoving one up the tailpipe is not likely to work, since it won't ever get hot enough, unless it's an electrically heated type.mgbloke wrote:Mike
Thanks for the reply.
AF was measured using a short piece of pipe with a lmbda sensor attached and stuffed up the tail pipe.
The rolling road is 4 weks old and I would have thought that if there was a problem with AF measurements it would have been sorted.
Mark
The MOT style probes that go up the exhaust are different, they measure CO levels rather than oxygen levels. Which type was this guy using? A proper lambda sensor that measures oxygen, or a CO probe?
Jeff
Mike
I dont normally try to accelerate from 30mph in 5th but it is actually quite a good indicator when you are setting and jetting a carb. The idea is to test it in as many ways as possible.
I was only commenting that the 600 doesent perform as well as the 500 in this respect.
The ultimate test will be on the track where im hoping the 600cfm edelbrock will eliminate some of the high speed running issues that I have had since the 4.6 was installed.( 2 years ).
Looking forward to the RR session on Thursday. Ill ask about the sensor that they use.
Mark
I dont normally try to accelerate from 30mph in 5th but it is actually quite a good indicator when you are setting and jetting a carb. The idea is to test it in as many ways as possible.
I was only commenting that the 600 doesent perform as well as the 500 in this respect.
The ultimate test will be on the track where im hoping the 600cfm edelbrock will eliminate some of the high speed running issues that I have had since the 4.6 was installed.( 2 years ).
Looking forward to the RR session on Thursday. Ill ask about the sensor that they use.
Mark
Well that's interesting... especially as I'm in the same position with my 4.6.
After endless problems with carburetion on my Edelbrock 500 (see my other thread), the tuning shop ripped it off & tried a Holley 600 double pumper. Out of the box it's been way better than the Edelbrock in the way that it drives & the engine note has surprisingly changed from the raw sound & lumpy idle it had with the Edelbrock to a deep bass & smoother idle with the Holley. It FEELS like it's at least as fast with the Holley & it seems to rev more freely.
BUT, it hasn't been on the dyno yet & subjective impressions don't mean much...
I'll let you know what the result is (after I get the rear brakes fixed so I can get it to the dyno shop!).
After endless problems with carburetion on my Edelbrock 500 (see my other thread), the tuning shop ripped it off & tried a Holley 600 double pumper. Out of the box it's been way better than the Edelbrock in the way that it drives & the engine note has surprisingly changed from the raw sound & lumpy idle it had with the Edelbrock to a deep bass & smoother idle with the Holley. It FEELS like it's at least as fast with the Holley & it seems to rev more freely.
BUT, it hasn't been on the dyno yet & subjective impressions don't mean much...
I'll let you know what the result is (after I get the rear brakes fixed so I can get it to the dyno shop!).
Sondar
I finally figured out what was causing problems with my Innovate WB lambda I got it re-calibrated and working properly. I did a 400 miles trip this week and had a nice time checking the carb settings. I went back to my last summer´s setting, .86 jet, 6755 rods, .95 sec jet and fitted the strongest pair of step-up springs. The idle is around 12:1, cruise mixture hovers around 13:1 and full throttle mixture is around 11:1. It is rich so next thing I will try is go back to .92 secondary jet.
Sondar, I would imagine that you have crap on that side of carb that supplies the rich bank of cylinders. Another thing that comes to mind, are you sure that your rods are actually the same ? Reason for asking is that I bought a new pair of rods 2 years ago (original packing, never opened) and once fitted the car did idle but stalled almost immediately past 1500 revs. It took some time but finally found out that the needles were totally different. The other was something like 67 cruise and the other 74 or something...
Too big a carb will run but will be a pain to setup especially at lower revs where air speed through venturies are slow. Holley has bigger primary plates so will be more sensitive than Edelbrock. Having said that, is there any real life data how the current manifolds work in 4,6 litre engines ? At least Edelbrock Performer was designed to 3,5 litre engine and now it has to feed a 20% bigger engine. Would a single plane manifold like Wildcat be actually better ?
Sondar, I would imagine that you have crap on that side of carb that supplies the rich bank of cylinders. Another thing that comes to mind, are you sure that your rods are actually the same ? Reason for asking is that I bought a new pair of rods 2 years ago (original packing, never opened) and once fitted the car did idle but stalled almost immediately past 1500 revs. It took some time but finally found out that the needles were totally different. The other was something like 67 cruise and the other 74 or something...
Too big a carb will run but will be a pain to setup especially at lower revs where air speed through venturies are slow. Holley has bigger primary plates so will be more sensitive than Edelbrock. Having said that, is there any real life data how the current manifolds work in 4,6 litre engines ? At least Edelbrock Performer was designed to 3,5 litre engine and now it has to feed a 20% bigger engine. Would a single plane manifold like Wildcat be actually better ?
I would recommend the Innovate WB, I got mine off Ebay but there are loads of places that do the kit now. I have never used in in a permanent install although it was bought for my Scim. The cars I have tuned with it have either had it put up the exhaust or into a proper pocket that was put in for tuning purposes.
Very cheap (I think) here 
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0120377581
Plenty of +ve feedback for them as well
They do the LM1 as well:
http://cgi.ebay.co.uk/Innovate-LM-1-Wid ... 0115945723
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0120377581
Plenty of +ve feedback for them as well
They do the LM1 as well:
http://cgi.ebay.co.uk/Innovate-LM-1-Wid ... 0115945723
