slant timing with turbo

[Slant Six Bumblebee]

I am about ready to pull the trigger on the parts for a turbo slant six. I have a good idea of everything I want to do except what I want to do for timing. I am going to be running a super six intake with a 2bbl carb (Still unsure what carb exactly) with all the hanger 18 mods boost referenced fuel pump. A junkyard t3 turbo running ~6-8psi no intercooler.

My only hiccup is for timing, I have a stock points distributor and am curious how to go about timing it. I DO NOT want to change over to hei or get a controller box. Yes i know about the gm 5pin and hobs switch or the msd boost retard controller. What do you think of the Mopar distributor timing limiter plates?
How to limit mechanical advance in a mopar distributor, tuning for street, strip or all out racing, cure that rich stinky idle, win races
Running this with no vac advance (because of boost) so it con only advance 10,12,14ect degrees past initial. I know it would take some tinkering and tuning to figure out.

 

[roccodart440]

Building a turbo slant and you really want to run the OEM points dizzy with no timing controller?

The easy way out is to keep your dizzy and use it to trigger a timing controller.

 

[Mattax]

Its a bit of a misleading infomercial.
The limiter is very clever idea IF that's what is needed.

It depends on where the curve needs to be adjusted.
That will depend on the curve the distributor has in it now.
Proper Timing depends on the speed of the combustion process and the speed of the piston.

You also will need to know what you want it to do when boost kicks in.
The turbo will change the compression and heat input.
Will you want to reference it to know when the turbo is spooling or just assume it is?

Successfully turboed slants are out there. See what they are doing. Even the EFI ones can be informative. The timing will be about the same so you can look at their tables.

 

[roccodart440]

When I look at turbo timing maps, I don't see how you could accomplish that with mechanical timing in a distributer.

 

[Mattax]

Not quite the same but see what Studebaker did for their supercharged engines.

 

[Slant Six Bumblebee]

Building a turbo slant and you really want to run the OEM points dizzy with no timing controller?

The easy way out is to keep your dizzy and use it to trigger a timing controller.

well i am eventuily going to upgrade to microsquirt and dont realhy wont to spend $500 on a ignition box. i know its a temporary solution but i this will be a crude setup with low psi.

 

[Slant Six Bumblebee]

Its a bit of a misleading infomercial.
The limiter is very clever idea IF that's what is needed.

It depends on where the curve needs to be adjusted.
That will depend on the curve the distributor has in it now.
Proper Timing depends on the speed of the combustion process and the speed of the piston.

You also will need to know what you want it to do when boost kicks in.
The turbo will change the compression and heat input.
Will you want to reference it to know when the turbo is spooling or just assume it is?

Successfully turboed slants are out there. See what they are doing. Even the EFI ones can be informative. The timing will be about the same so you can look at their tables.

i understand the limiter wont give me the corect timing curve exactily but wont it stop my engine for advancing too far under boost causing detonation.

 

[RustyRatRod]

I know N/A slant sixes don't appreciate any more than about 30 degrees total. I would only imagine forced induction would like either less total, or a curve that delays it more so than N/A. In the end, regardless of ignition, it's something you're just going to have to experiment with. Maybe a baseline of 25 total all in by 3000 is a good starting point. That's a kinda lazy curve for N/A, but for boost, maybe not....and I don't think it would be enough to hurt something.

 

[Slant Six Bumblebee]

I know N/A slant sixes don't appreciate any more than about 30 degrees total. I would only imagine forced induction would like either less total, or a curve that delays it more so than N/A. In the end, regardless of ignition, it's something you're just going to have to experiment with. Maybe a baseline of 25 total all in by 3000 is a good starting point. That's a kinda lazy curve for N/A, but for boost, maybe not....and I don't think it would be enough to hurt something.

How would i change the all in timing? is that limiter plate a good idea? i dont want to drop my inital timing down to where my total is 25?

 

[RustyRatRod]

How would i change the all in timing? is that limiter plate a good idea? i dont want to drop my inital timing down to where my total is 25?

I like the limiter plate idea. I have one on the electronic distributor in Vixen now and one in the points distributor that came out. Word of caution though. The actual timing you "end up" with is different than what the slots are marked for. On both of mine, the slots did not limit the total timing "as much" as they were marked. I don't know it that was because of it being a slant 6 distributor or not. I don't believe it is, because I've seen others on here with different application also say their plate did not match up with what the slots were marked for. I forget what the "least" advance slot is besides zero, but that's where mine is and it's limited to 10 degrees mechanical advance. So I run "around" 20 initial. But keep in mind, mine is also N/A.

 

[Slant Six Bumblebee]

I like the limiter plate idea. I have one on the electronic distributor in Vixen now and one in the points distributor that came out. Word of caution though. The actual timing you "end up" with is different than what the slots are marked for. On both of mine, the slots did not limit the total timing "as much" as they were marked. I don't know it that was because of it being a slant 6 distributor or not. I don't believe it is, because I've seen others on here with different application also say their plate did not match up with what the slots were marked for. I forget what the "least" advance slot is besides zero, but that's where mine is and it's limited to 10 degrees mechanical advance. So I run "around" 20 initial. But keep in mind, mine is also N/A.

it would take some experimenting. 20 initial seams like a lot (dident slants come with 15btdc "stock") and if the limiter is off marking if i set my initial to 15 and the smallest limiter on the plate is 10 and that is not acuret that would put me over 25?

 

[RustyRatRod]

it would take some experimenting. 20 initial seams like a lot (dident slants come with 15btdc "stock") and if the limiter is off marking if i set my initial to 15 and the smallest limiter on the plate is 10 and that is not acuret that would put me over 25?

Oh hell no. Some came 0 initial. I think they actually ranged from -2 to 5 or 6. It would put you over 25 if you gave it 20 initial, but a turbo engine will not want 20 I don't believe. Mine does because the camshaft has so much duration. 250@ .050

 

[Slant Six Bumblebee]

Oh hell no. Some came 0 initial. I think they actually ranged from -2 to 5 or 6. It would put you over 25 if you gave it 20 initial, but a turbo engine will not want 20 I don't believe. Mine does because the camshaft has so much duration. 250@ .050

Ok that makes sense so if i set inital to ~8 and then I can start with the 10 degree limiter and find where it goes on .org they are limiting to 18 under boost on pump gas. how much initial is to little? if the 10 degree one is really more say 12 i would only have 6 inital.