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Topic Review (Newest First)
09-25-2012 05:15 PM
painted jester
Quote:
Originally Posted by cobalt327 View Post
W/all due respect, while I do often recommend the RPM intake, you will never see me recommend the Air Gap intake.
Cobalt I only mentioned the air gap because many people don't know about the frosting problem ! I Understood your post and I knew you didn't recommend the air gap intake!

It was the way I overcame the frosting I wanted you to see LOL. I thought you might be interested.

Jester
09-25-2012 03:41 PM
ap72
Quote:
Originally Posted by vinniekq2 View Post
Daubers the 650 will work.You need to find a shop where you can try a 650 and a 750.Now that ap72 has added a whole new can of worms I have to comment,,,

AP72 what you said about dynos is true.an inertia dyno like the dynojet works best at W.O.T. testing,this is because it cannot load the car like a Mustang dyno. The mustang uses electric magnetic force to control rpm instead of just the weight of the roller wheel.

So now you have your car on the mustang roller,set it for 3.000 engine rpm.that will be different at the roller.So,Now,,, at 1/4 throttle the fuel curve cance be checked then advance throttle to 1/2,and check mixtures,and full throttle,no change in rpm.
With the carb,you are done,pick one throttle setting as an average and adjust carb re do for 4,000 rpm and 5,000 rpm etc.You only have 5 adjustments on a carb

With fuel injection,you can tune all the fuel curves independently based on throttle position,long story short you can have both fuel economy and max power.It might take 2 days on the dyno,,,this is how a valet key works on fuel injection.It changes programs so that horse power can be taken out of an engine. The fuel injection system when set up with modern crank fired ignition can take this to yet another level by making the ignition curve match the different fuel curves to improve mileage and power.
some fuel injection systems can have over 300 adjustments.
5-6k for a fuel injection system that is vastly superior in everyway or $500.oo for a carb.
Back to what I said before,a track tune is different from a street tune.(for carbs)
the only thing you cannot account for on a carb that you can account for with EFI is a change in air density or humidity and to a lesser extent engine RPM (which is somewhat irrelevant)- or system problems such as a vacuum leak.
09-25-2012 03:29 PM
painted jester
Quote:
Originally Posted by cobalt327 View Post
Do this: Try the carb the way it is. If it was really built for the engine, it may surprise you and work just fine. I'd swap the intake if it was me- considering you're not just racing it.
Cobalts right: that BG on a different intake may act like a different carb and be very streetable.

I see the distributor on the picture and it looks like the vacuum advance is disconnected? If it is its probably locked out . getting the distributor re curved may help a lot for street manners. I don't see a pcv either that would help too!! you really need crank case evacuation no mater what method you use you need it! a pcv will also add a little air to the intake charge helping a little more!

Jester
09-25-2012 02:53 PM
painted jester
Quote:
Originally Posted by Daubers View Post
For my application and use, will the 650 be enough out of the box or should I look into re jetting or possibly taking it to a carb shop to add a little more flow? I have been reading a lot of other threads and they mostly all seem to say a bigger carb is needed.
The only problem I see that you may have is at wide open throttle! with a true 180 intake and a 650 cfm carb a single cylinders can only draw 325 CFM max because the intake is divided and that divides the carb in half so that the cylinder only draws from one side of the carb. At idle and light cruising the power valve is closed, but when the throttle increases the vacuum drops and the valve opens!!! If your cylinders draws more then 325 cfm at wide open throttle your vacuum signal will climb closing the power valve!

On a 360 intake there is 650 cfm available to each cylinder because there is no divider!!! your engine had the big BG carb that flowed at least 900 cfm (guessing) so it was built for an engine that's cylinder pulls and expels gobs of air Over the 650s capability to supply at very high speed with the 650 on a 180 intake your engine will starve For air and compounding that is the High vacuum signal that closes the power valve

That's why an open spacer under the carb helps on the 180 intakes! Some 180s have a cut out in the divider helping a little but would still be restrictive on your engine!

A bigger carb is needed for wide open throttle but you have one!!!! a BG LOL You'll be fine with the 650 for all normal driving and for short full throttle bursts till the engine demand exceeds the carbs ability to feed the engine!!!! Man that eng. is a great candidate for tripower with progressive linkage ( THINK ABOUT IT )

If you send the 650 to a carb builder he will want the info on the engine and build a carb to match the build LOL youll end up with another like the BG LOL ( just a joke LOL)

Thats a simple explanation I hope LOL

Jester
09-25-2012 12:22 PM
painted jester
Quote:
Originally Posted by ap72 View Post
for tuning on the street it is VERY IMPORTANT to tune with the pvcr's for WOT and jets ONLY FOR CRUISE. So many people think the jets are for WOT and they ARE NOT.
Are you talking about a 2 barrel it seems to me you forgot the whole secondary circuit! The power valve comes Into play about half throttle and the secondary jets come in when the rear butterflies open!!! At wide open throttle at the drags your vacuum change drastically or gas will run back and leave the rear power valve dry and shut the power valve down ! That's why a lot of racers run no power valves!!!! But on roundy rounders your vacuum is pretty stable all around the track. So your tuning with power valves just hit the back wall Your reading the wrong Magazines!!!!!!

The only carb I now that does that is a 3 stage with a rear power valve for marine and roundy rounders !!! This carb would not have a rear power valve !!! If it did it would absolutely kill a drag motor !!!!!!

Jester
09-25-2012 12:02 PM
painted jester
Quote:
Originally Posted by ap72 View Post
I'd forget the 650 and just send your carb to a very reputable shop to be rebuilt and given a baseline tune. It'll be about the same cost but you end up with a better carb.
I know we're on the 650 now, but I do rebuilds and custom set ups in my area on mostly Holleys and copy cat Holleys, before I retired I did them all, My labor rate on a stock rebuild is $250.00 Thats about average here ! Thats Labor' materials like metering blocks, kit, butterfly's, accelerator pump blocks,etc that isnt in the kits is extra, milling base plates , metering blocks etc is extra, bent control arms extra. Let alone shipping charges!

If I some one sent me that BG carb the go through and redo for street The charge would be much higher, if the metering block has a power valve the power valve restrictor's have been opened up if its a solid block it would need replacing etc etc!

The charge to redo it would be higher then a new #4150 650 double pumper 2 corner carb that sells for around 370 dollars!

I also had a rear wheel Dino in my shop and used Dino's off & on since the 70s . Testing in a Dino room can get you close in a controlled conditioned room but after the Dino tuning you should final tune at a track or safe area to bring it into real world adjustments Because a Dino load and a road or track load are completely different and a load at the drag strip has even more differences. A load is usually a lot more on a Dino then in the real world.

Jester
09-25-2012 09:31 AM
cobalt327 Do this: Try the carb the way it is. If it was really built for the engine, it may surprise you and work just fine. I'd swap the intake if it was me- considering you're not just racing it.
09-25-2012 08:49 AM
vinniekq2 Daubers the 650 will work.You need to find a shop where you can try a 650 and a 750.Now that ap72 has added a whole new can of worms I have to comment,,,

AP72 what you said about dynos is true.an inertia dyno like the dynojet works best at W.O.T. testing,this is because it cannot load the car like a Mustang dyno. The mustang uses electric magnetic force to control rpm instead of just the weight of the roller wheel.

So now you have your car on the mustang roller,set it for 3.000 engine rpm.that will be different at the roller.So,Now,,, at 1/4 throttle the fuel curve cance be checked then advance throttle to 1/2,and check mixtures,and full throttle,no change in rpm.
With the carb,you are done,pick one throttle setting as an average and adjust carb re do for 4,000 rpm and 5,000 rpm etc.You only have 5 adjustments on a carb

With fuel injection,you can tune all the fuel curves independently based on throttle position,long story short you can have both fuel economy and max power.It might take 2 days on the dyno,,,this is how a valet key works on fuel injection.It changes programs so that horse power can be taken out of an engine. The fuel injection system when set up with modern crank fired ignition can take this to yet another level by making the ignition curve match the different fuel curves to improve mileage and power.
some fuel injection systems can have over 300 adjustments.
5-6k for a fuel injection system that is vastly superior in everyway or $500.oo for a carb.
Back to what I said before,a track tune is different from a street tune.(for carbs)
09-25-2012 08:43 AM
cobalt327
Quote:
Originally Posted by Daubers View Post
For my application and use, will the 650 be enough out of the box or should I look into re jetting or possibly taking it to a carb shop to add a little more flow? I have been reading a lot of other threads and they mostly all seem to say a bigger carb is needed.
Check your PM box.
09-25-2012 08:42 AM
cobalt327
Quote:
Originally Posted by painted jester View Post
Cobalt; those air gap intakes...
W/all due respect, while I do often recommend the RPM intake, you will never see me recommend the Air Gap intake.
09-25-2012 07:39 AM
Daubers For my application and use, will the 650 be enough out of the box or should I look into re jetting or possibly taking it to a carb shop to add a little more flow? I have been reading a lot of other threads and they mostly all seem to say a bigger carb is needed.
09-25-2012 06:04 AM
ap72
Quote:
Originally Posted by vinniekq2 View Post
ap72,if you tune the car for maximum power,you might be surprised at the street manners.
My direct questions to you are,,,have you drag raced? Have you driven the same car that was tuned as an example,,,12:1 Vs 13:1 a/f ratios to see if there is a difference?If you circle track race then disreguard those questions

If you tune the car properly you'd be surprised to find the street manners improve. I've drag raced a little, the track is too far and the lines are too long, when I do go I usually just park it and watch. I have tuned quite a few carbs though and am currently stepping into EFI and one of the few never failing rules is that you tune the WOT mixture for max power and the part throttle mixture for best economy.

That's actually the entire point of dyno tuning- most neighborhood dynos can ONLY tune for WOT.
09-24-2012 08:57 PM
vinniekq2 ap72,if you tune the car for maximum power,you might be surprised at the street manners.
My direct questions to you are,,,have you drag raced? Have you driven the same car that was tuned as an example,,,12:1 Vs 13:1 a/f ratios to see if there is a difference?If you circle track race then disreguard those questions
09-24-2012 08:54 PM
Daubers
Quote:
Originally Posted by ap72 View Post
I'd forget the 650 and just send your carb to a very reputable shop to be rebuilt and given a baseline tune. It'll be about the same cost but you end up with a better carb.
Considering i am not paying anything for the 650 i don't see how its about the same price
09-24-2012 08:50 PM
ap72
Quote:
Originally Posted by Daubers View Post
Looks like ill be trading for a 650 double pumper

Now since i have everyone here that knows my setup, should I use the current victor jr intake or swap for an edelbrock performer rpm ( already have one )?
I'd forget the 650 and just send your carb to a very reputable shop to be rebuilt and given a baseline tune. It'll be about the same cost but you end up with a better carb.
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