What are the advantages of boost retard systems over static

moggy · Post by **moggy** » Fri May 11, 2001 10:18 am

On my 2366cc supercharged setup I'm running 24degrees static advance (i.e. it don't retard or advance it's always at 24degrees)

What, approximately, are the advantages, power and drivability I should experience if I fitted a boost retard system?

Thinking MSD or 205...

Derrick from NC · Post by **Derrick from NC** » Fri May 11, 2001 1:18 pm

[QUOTE]Originally posted by moggy:
On my 2366cc supercharged setup I'm running 24degrees static advance (i.e. it don't retard or advance it's always at 24degrees)

What, approximately, are the advantages, power and drivability I should experience if I fitted a boost retard system?

If your running that monster then I don't hardly feel qualified in any way to give my $.02. For one thing, you should find cranking/starting easier with an mech advance distributor set around 0-8 vs 24deg all the time, which would advance to 28-32deg at 3000rpm, then retard as needed under boost. I hoping an EMS will give my 2332 turbo all those advantages. Driveability/smoothness while not on boost & the transition to boost? I would like the answer to that one too!

Steve Arndt · Post by **Steve Arndt** » Fri May 11, 2001 1:25 pm

Having proper advance when cruising under high vacuum low load conditions would increase your gas mpg greatly. Around 38 is optimimal I believe under these conditions. Then 28 under light load with no boost still, and retarded from there when you get into positive pressure. You need JMR's DTA and Jenvey throttle bodies my man!

Muffler Mike · Post by **Muffler Mike** » Fri May 11, 2001 2:48 pm

I say under race condidtions when boost should be on most of the time, not much. and just one more thing that could go wrong and loose the race. BUT when we first got jims car going, we set his timing at 24 full advance in an 009 and bent the advancing stop tabs. it was bareable to drive but was mising something. He then purchased a msd btm box. we then stuck his full timing up to 35 and had it back off to 24 when it got to 15lbs of boost. What a night and day difference it made to drive it on the street. much more responsive and you could actually roll into the throttle pretty fast. With it being a draw through it was a pleasure to drive. if you have a fuel injection it may not be as necessary..

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Muffler Mike
UltimateBB.com

[This message has been edited by Muffler Mike (edited 05-11-2001).]

Sharkey · Post by **Sharkey** » Fri May 11, 2001 4:52 pm

<BLOCKQUOTE>quote:<HR>Originally posted by Muffler Mike:
We then stuck his full timing up to 35 and had it back off to 24 when it got to 15lbs of boost.<HR></BLOCKQUOTE>

And that works? That's less than 1 degree of retard per PSI. Most recommendations I have seen range from 1-3. What CR was used? What octane?

bad62bug · Post by **bad62bug** » Fri May 11, 2001 8:02 pm

<BLOCKQUOTE>quote:<HR>Originally posted by Sharkey:
And that works? That's less than 1 degree of retard per PSI. Most recommendations I have seen range from 1-3. What CR was used? What octane?<HR></BLOCKQUOTE>

I think about 24 degrees is about as far you want to go to much timing retard is a bad thing to

Muffler Mike · Post by **Muffler Mike** » Tue May 15, 2001 7:22 am

<BLOCKQUOTE>quote:<HR>Originally posted by Sharkey:
And that works? That's less than 1 degree of retard per PSI. Most recommendations I have seen range from 1-3. What CR was used? What octane?<HR></BLOCKQUOTE>

Worked great. we ended up with 7.2:1 cr and used VP Red fuel (107 or 109 octain) when we did try to get aggressive on the retard, closer to 1 deg per pound, the car wouldnt get out of its own way.

Matt Keene · Post by **Matt Keene** » Tue May 15, 2001 10:06 am

I go along with Mike and Steve- the retard devices are well worth while if the car is used on the street. I use a Jacobs boost retarding system and it works! Overall response and fuel mileage increased at cruising speeds (no boost) because the ignition was able to run full advance. The beauty of this system is that you can adjust your no boost ignition whilst driving-therefore under real conditions. The boost retard is also adjustable in the same manner and proved to save time and hassle. I rate these systems, although I have heard a lot of bad vibes about the EMS system as a friend had and engine explode running EMS. He didn't rate its limited adjustabillity either...

moggy · Post by **moggy** » Fri May 18, 2001 5:57 am

Matt, have you got the contact details of the guy you got your MSD and Jacobs stuff off?

Cheers

turbo6bar · Post by **turbo6bar** » Fri May 18, 2001 11:36 pm

Hey Moggy, just a thought, but why don't you run a vacuum advance distributor coupled with a boost retard box. This would give you easier starting, better acceleration, cruising, and fuel mileage, as well as retarded timing while under boost. I don't know how you drive, but I think it would be safe to say well over half the driving on the street is under zero boost.

Better yet, go with aftermarket FI and reap a lot of benefits.

Regards,
jay

moggy · Post by **moggy** » Sat May 19, 2001 1:24 pm

Good idea Jay, but unfortunately the blower mount prevents the use of a vacuumed dissy. As you can see from the pic theres no room for that vaccuum thing on the side of the dissy, therefore my only option is an electronoic one.

Cheers