Jump to content
Ultimate Subaru Message Board
Sign in to follow this  
LPGsuperchargedBrumby

N/A distributor on a turbo

Recommended Posts

does any know what kind of results i would get from putting a carby distributor on a turbo motor (apart from the lack of knock senser)

 

what i want to know is what sort of retard i would get under boost......i figger if it advances under vacuum then its got to retard under boost

 

do the turbos with a vacuum disty have a differen't vac unit... i.e like the early mazda distys with two hoses going into them

Share this post


Link to post
Share on other sites

you can find 4wd, and 2wd distributors from na mpfi motors. they have the two vac hoses. or you can get a disty from a carb, with only the one vac line.

 

more advance, when it sees no vacume, so that means when you hit boost, your at full advance. which is cool, if you have everything else tuned right =]

Share this post


Link to post
Share on other sites

the result is ok; been running the standard hitachi dizzy for years; I had the static timing at 10-12degrees tho:slobber: , as I didn't know that the static timing for the ea82t is supposed to be 25degrees!! But at least I didn't seem to have any pinging problems and standard unleaded, maybe the response wasn't so good from start, but once its reving and goin in boost the power does really come on - bit confused how this ties up with whats happening with advance in this case?

trying static timing of 20degrees atm - around town its great, up the mountain, high load, hmmm not so sure..started to get some ping so backed off.

Share this post


Link to post
Share on other sites

more advance, when it sees no vacume, so that means when you hit boost, your at full advance. which is cool, if you have everything else tuned right =]

 

hmmm full advance under boost.....is that like 20deg static + 20deg mechanical/vacuum advance = 45deg btcd under full boost?

 

don't know if i like the sound of that....

 

good thing propane is 104 octane

Share this post


Link to post
Share on other sites

IIRC 1987+ all the distys are the same....two diff PN's but basically the same item.

 

1985-early 1987...a train load of distys to choose from.

Share this post


Link to post
Share on other sites
hmmm full advance under boost.....

 

Nah, you should have no advance during boost, the line going to the vacuum diaphragm will have boost pressure, so the advance unit wont move at all, unless you have a diaphragm off a turbo on it.

Share this post


Link to post
Share on other sites
Nah, you should have no advance during boost, the line going to the vacuum diaphragm will have boost pressure, so the advance unit wont move at all, unless you have a diaphragm off a turbo on it.

 

why wouldn't it move...if it moves one way when it has negative pressure on it surly it would move the other way when it has positive pressure on it?

Share this post


Link to post
Share on other sites
why wouldn't it move...if it moves one way when it has negative pressure on it surly it would move the other way when it has positive pressure on it?

 

It may retard the timing, but it may not have any room to move that way, im not sure.

Share this post


Link to post
Share on other sites
does any know what kind of results i would get from putting a carby distributor on a turbo motor (apart from the lack of knock senser)

 

what i want to know is what sort of retard i would get under boost......i figger if it advances under vacuum then its got to retard under boost

 

do the turbos with a vacuum disty have a differen't vac unit... i.e like the early mazda distys with two hoses going into them

 

The vacuum units are different,but not much in actual advance specs.

Turbo vacuum diaphrams only provide 3* of retard under full stock boost.I seem to recall that non-turbo units also

have enough movement available to provide some retard under boost.I didn`t measure,but,they seemed similar.For a while,I was considering using one on a turbo dizzy(arm is too short)

 

The difference in turbo and NA dizzys is more in the centrifigual advance curves.Turbos advance more slowy reaching full 10* advance at 2800 rpm while the NA is fully advanced at 1900 or so.

You could slow the advance of the NA unit by installing stiffer advance springs or lightening the weights.

Then again,the extra octane of LPG might match nicely w/the quicker advance.

 

An 85-86 MPFI dizzy would allow you to retain the knock sensor.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×