vac advance on street car?

vac advance on street car? - 12/27/11 05:58 PM

Hello, I've been reading a lot about the need for Vacuum advance distributor for a street car. But I swear 90% of the BB street builds I see have a MSD Pro Billet non vac advance distributor. So do I need the vacuum advance? This is a mild 500hp BB street build. Thanks

Posted By: MR_P_BODY

Re: vac advance on street car? - 12/27/11 06:01 PM

Quote:

Hello, I've been reading a lot about the need for Vacuum advance distributor for a street car. But I swear 90% of the BB street builds I see have a MSD Pro Billet non vac advance distributor. So do I need the vacuum advance? This is a mild 500hp BB street build. Thanks

They do help for fuel mileage when your cruising

Posted By: Mr.Yuck

Re: vac advance on street car? - 12/27/11 06:08 PM

I can't recall the last time I hooked up a vac advance...

Posted By: 1_WILD_RT

Re: vac advance on street car? - 12/27/11 06:12 PM

Quote:

I can't recall the last time I hooked up a vac advance...

Then your wasting fuel.... Unfortunately most serious aftermarket ignitions are designed by guys with more race thinking than street thinking....

Posted By: Pacnorthcuda

Re: vac advance on street car? - 12/27/11 06:19 PM

Quote:

Quote:

Hello, I've been reading a lot about the need for Vacuum advance distributor for a street car. But I swear 90% of the BB street builds I see have a MSD Pro Billet non vac advance distributor. So do I need the vacuum advance? This is a mild 500hp BB street build. Thanks

They do help for fuel mileage when your cruising

and part throttle response.

Posted By: Mr.Yuck

Re: vac advance on street car? - 12/27/11 07:12 PM

Quote:

Quote:

I can't recall the last time I hooked up a vac advance...

Then your wasting fuel.... Unfortunately most serious aftermarket ignitions are designed by guys with more race thinking than street thinking....

If so it isn't much. The last 3 engines (2x440's) had curved and welded distribs. The Supercharged 440 in my 67 coronet netted me 12mpg w/ 3.91's doing 65-70mph or so over 50+ miles. The 340 swinger w/ holley 750DP and 3.55's got over 17mpg at 65-70 and this 440-6 build w/ solid roller cam avg'd around 12-13 putting (40-45mph) on back roads to and from the track (40+ miles) How much better would a vac advance be?

Posted By: lewtot184

Re: vac advance on street car? - 12/27/11 07:15 PM

i use them on my streeters. they make perfect sense, and are tunable. they help keep the combustion chambers clean and aid in fuel mileage. i used to be the "full centrifugal only" type guy but got away from that thinking years ago.

Attached picture 6986742-100_0290.jpg

Posted By: Mr.Yuck

Re: vac advance on street car? - 12/27/11 07:20 PM

Quote:

i use them on my streeters. they make perfect sense, and are tunable. they help keep the combustion chambers clean and aid in fuel mileage. i used to be the "full centrifugal only" type guy but got away from that thinking years ago.

how much does one want it to advance??

Posted By: lewtot184

Re: vac advance on street car? - 12/27/11 07:26 PM

total advance in cruise mode is around 52 degrees. this will vary depending how much advance is in the vacuum can. they are marked with a number. i've used 8,9, and 10 degree units. the 8 or 9 has worked best for me.

Posted By: Pacnorthcuda

Re: vac advance on street car? - 12/27/11 07:35 PM

Yep--I adjust to 52-54 total.

Posted By: Mr.Yuck

Re: vac advance on street car? - 12/27/11 07:57 PM

Quote:

Yep--I adjust to 52-54 total.

Is that too much for a 11:1+ motor

Posted By: Pacnorthcuda

Re: vac advance on street car? - 12/27/11 08:00 PM

Quote:

Quote:

Yep--I adjust to 52-54 total.

Is that too much for a 11:1+ motor

It might very well be too much, depending on what fuel you're feeding it. If you get any part throttle pinging then back off.

Posted By: 383man

Re: vac advance on street car? - 12/27/11 08:27 PM

I also build my eng more toward the race mode then a cruiser even though I cruise in it 99% of the time. I just have a mech only Mallory dist and it has full advance by 1800 rpm of 38 degrees. I dont think I would want 52 or so myself with my eng and if I was that worried about gas milage I would be in the wrong hobby.

Course I think race mode and that is full throttle the vacum advance dont work anyway. Ron

Posted By: Mr.Yuck

Re: vac advance on street car? - 12/27/11 09:44 PM

Quote:

I also build my eng more toward the race mode then a cruiser even though I cruise in it 99% of the time. I just have a mech only Mallory dist and it has full advance by 1800 rpm of 38 degrees. I dont think I would want 52 or so myself with my eng and if I was that worried about gas milage I would be in the wrong hobby. Course I think race mode and that is full throttle the vacum advance dont work anyway. Ron

same boat here Ron. I run 93..I have mine in full at 2k (38*) The meth/H2O injection helps a ton under load, but it won't fog until vaccuum is at zero an at cruise my vac gauge is at 20+

Posted By: Anonymous

Re: vac advance on street car? - 12/27/11 09:51 PM

Meh,

Haven't run vacuum advance in quite a few years now.

The last 318/360 headed motor that we pulled apart that I had run this way looked clean as a whistle on the tops of the pistons and would pull down decent mileage for what it was.

The 440 used to get 14-15 mph going down the Interstate at 70mph with 3.23 gears, .528 mechanical, headers and Holley 750.

Posted By: mikemee1331

Re: vac advance on street car? - 12/27/11 10:13 PM

if you can use it, then use it. your MPG will be slightly better.

Posted By: Crazy68Dart

Re: vac advance on street car? - 12/27/11 10:37 PM

There was a pretty good thread about this a while back. Try a search.

Depending on how it is hooked up, can help with mileage, cooling, etc.

Posted By: buildanother

Re: vac advance on street car? - 12/27/11 10:39 PM

It becomes a pain if you have advertised dura. at 300 or more.

Posted By: Supercuda

Re: vac advance on street car? - 12/28/11 12:10 AM

Quote:

It becomes a pain if you have advertised dura. at 300 or more.

Not really a street motor at that point now is it?

Posted By: buildanother

Re: vac advance on street car? - 12/28/11 12:47 AM

Mine was. Did a great job testing parked car alarms too.

Posted By: Supercuda

Re: vac advance on street car? - 12/28/11 03:48 AM

Quote:

Mine was. Did a great job testing parked car alarms too.

Always some character making this claim. If Don Garlits drove Swamp Rat on the street it wouldn't be a street car nor would the engine be "streetable". 300 degree cams are not street or streetable regardless.

Posted By: buildanother

Re: vac advance on street car? - 12/28/11 02:19 PM

Yes, there are characters out there and some take their cars to shows and cruise nights. There are many in this area. Not daily drivers usually.

Posted By: Dodgem

Re: vac advance on street car? - 12/28/11 06:22 PM

Advertised duration of 300 is a street cam??? IMHO