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I recently purchased a used B&M 144 supercharger. I finally got it installed and I can't get it to stay running with out constantly giving it gas. I've never messed with a supercharger before and kind of winging it. I used the electronic fuel pump that was already on the car and the fuel gauge shows 6 psi which b&m says it needs so I left it. The carb is a 750 holley demon double pumper. Any ideas on what I can check?
what engine is this on?
what is the initial timing?
what carb do you have a Holley or a Demon ?
what is the altitude where you are at?
what jets are in the carb?
what distributor and plugs are you running? gapped @ ??
Ok, I"m going to answer these the best of my knowledge. I bought this setup used so only know what I was told. Engine is Chevy 350. As far as timing, I just found top dead center on #1 cylinder, dropped the distributor in and pointed router at #1 cylinder.Then I bolted distributor down just tight enough that I could advance/retard it. The only time it starts is when the vacuum advance is right against the supercharger. The carb is a 750 demon. I dont know what jets are in the carb. Distributor/Cap says Delco/Remy. Gap on spark plugs are .35Quote:
Originally Posted by vinces427bb
ok it does sound like you do not have enough initial timing advance.
if your distributor vac.adv. can is tight against the blower,
you might want to put/move the plug wires back 1-terminal in CCW direction looking down at the cap.
this will allow you to advance the distributor more to reach the correct initial timing advance...:nightmare:
insure you keep the correct firing order and separate the #5 & #7 plug wires, they are prone to cross-fire...
obtain a timing light and check-adjust the timing for 12*-18* BTC for starters.
what type of distributor do you have: stock or aftermarket?
delco-remy sounds stock = but is it an HEI or does it have points?
you will want to limit the total timing advance to 28*-34* based on the boost psi level...:encouragement:
Thanks for the response. I don't understand what you mean with the #5 and #7 wires, separating them? I'm not sure if its a stock or hei distibutor. I'm going to post a picture. This is not my setup but the same distributor.Quote:
Originally Posted by vinces427bb
http://i89.photobucket.com/albums/k2...o/DSCN0151.jpg
looks like you have a factory HEI distributor with the coil inside the cap.
the stock SBC firing order 18436572 has cylinders #5 & #7 next to each other,
if the wires are routed too close to each other the #7 cylinder can cross-fire at the wrong time.
this will make the engine run poorly = like crap
So I haven't had any luck with this. So I pulled out my original carb which i believe is a edelbrock 650 and threw it on. Not only did the engine start right up with out giving it gas, it idled perfect too right off the bat. Can I get away with running this carb? I don't race or need full potential of the blower because I just cruise around in it. Just figured I would throw it out there and see what some experienced people think. Thanks
So I finally went out and bought a holley700 carb supercharger specific. I hooked it all up and and seemed to be ok but when the engine was rev'd or down shifted it would backfire. After looking through the directions it showed that you need to run a vacuum line from manifold to the carb so the powervalve doesn't stay open. I did this today and engine idles perfect and sounds great and no backfiring when rev'd up. As soon as you put it in gear, it dies. I tried adjusting the distributor a little to see if it would help. Everytime it dies as soon as you put it in gear. Any help?
does the holley have a 4-corner idle or just the front 2 idle jets?
these need to be adjusted Evenly to the highest idle speed (between 1/4 turn to 2-turns out from the lightly seated...
what is the initial timing setting?? you might start at 12*-18* initial with the distributor vacuum line plugged.
what idle speed are you attempting to use?? you may need to set-idle speed up alittle to keep it running in gear..
maybe try to end up with idle of 900-1000rpm in gear...
i don't know if you have a stock transmission and torque converter, so these are the several thing to start with...:encouragement:
Thanks for the response. It just has the front 2 idle jets and I turned them both 1 turn out and it stopped the problem. I'll have to try to get some help with the timing. Really don't know too much about it. Do I just start the engine and turn on timing light and plug the distributor vacuum line like you said and try to set it to 12-18*. Seems to be idling around 900-1000 rpmQuote:
Originally Posted by vinces427bb