Dellorto dual DRLA 45 rich at 2500rpm

[hearmyevil]

I running dual Dellorto DRLA 45 on a type 4 2.0 13psi of boost. I can not get any power at 2500 it just fouls out. It idles smooth and run great from 3000 to red line. I have changed jets so many time I am running out of ideals.
right now turbo e tubes
165 mains
50 idle
200 air

[Dan Dryden]

How are you controlling ignition?

[hearmyevil]

My distributor is an 050 and I have an MSD 6BTM system. At 2500 its also is jerking and plugs are black. As soon as it gets to 2800 it smooths out.

[Coyote]

what is your static advance? total advance? camshaft? CR ratio? position of your bufferflies at idle? how far the idle screws are open? etc... the more you can tell us, the more we can help you.

[Dan Dryden]

Every engine is different but when I ran my 1776 type 1 on dual Dell 40's at 13.5psi I had 55 idles & 180 mains. (Can't remember the air corrector size). Idle was smooth , progression was good considering I was running a restricted 009. Angle tcs10 cam, static comp 7.5:1. I originally suspected your advance curve to be wrong but perhaps the progression from idle to main circuit needs attention. Have you tried bigger idle jets?

[Coyote]

My distributor is an 050 and I have an MSD 6BTM system. At 2500 its also is jerking and plugs are black. As soon as it gets to 2800 it smooths out.

Well, I don't know what is the centrifugal advance of the 050, but I suspect that your initial advance is not enough from idle up to 2800. That's can explain why your engine run fine past 2800. it's because at this rpm, you have enough advance.

I am pretty sure that 50 idle jets are not too much. Is it really idle smooth? have you a wideband handy ?

[Clonebug]

If I remember research reading correctly, don't the airs control when the mains kick in???

What emulsion tubes are you running??

Are you using the turbo tubes??

Clonebug

[Coyote]

If I remember research reading correctly, don't the airs control when the mains kick in???

yes. the bigger they are, the sooner the main kick in and therefore it is possible to have too much overlap (main+idle at the same time).

[Clonebug]

If I remember research reading correctly, don't the airs control when the mains kick in???

yes. the bigger they are, the sooner the main kick in and therefore it is possible to have too much overlap (main+idle at the same time).

Why not try a 180 air and leave everything else the same and see if that helps your mid range.

Is this in cruise or under full load boost??

Clonebug

[hearmyevil]

I have 27 degrees of advanced and timing is -24 at 3500

[hearmyevil]

turbo emulsion tubes

[Clonebug]

I have 27 degrees of advanced and timing is -24 at 3500

Huh??

Could you clear this up a bit??

You should have around 7.5 degrees BTDC at idle and around 30 degrees at 3000 rpm.

Does the msd retard on boost???

if so use it to retard and set the distributor to go to 30 or 32 degrees BTDC by 2800 to 3000 rpm.

With my MS1 and EDIS I have start rpm at 7.5 Degrees
Idle is at 12 to 15 degrees BTDC
3000 rpm is at 32 degrees and at 12 lbs boost it is retarded to 21 degrees BTDC due to pinging at full load.

Clonebug

[turbobaja]

At 2500 its also is jerking and plugs are black. As soon as it gets to 2800 it smooths out.

Can you watch your timing with a strobe when this is happening? Free revving you should be around 25°-28° at this rpm and approaching 30°-32° by 3-3.5K rpm.

I have 27 degrees of advanced and timing is -24 at 3500

This is way too low (assuming 24° BTDC) for just free revving w/out a load. It would be a safe area to be when making boost @ 3500rpm and up. Let the MSD6 BTM handle that. Set your full advance to 30-32° BTDC @ 3500rpm and turn the knob on the BTM to somewhere just under 1°/lb of boost. So by the time you reach ~13psi boost pressure, your timing is down around 24°. If the distributor advances a total of 27° from idle to ~3500, you need to do something to limit it's advance travel or get a different distributor. Don't set your idle timing super low just to keep the total advance within reason. You only need about 20° mechanical advance from the distributor.

Do you know your base fuel pressure, accurately? The 50 idles should be fine, 200 airs might be causing your rich in transition problem, but you've got to get your timing dialed first.

[hearmyevil]

I just started messing with the car. still rich. it rich all the time. wot is the only time it runs good.

[Clonebug]

Lean it out on idle and no load mid ranges. If it doesn't run good off boost it will be tough to get it set correctly when WOT full load.