Newbie in the carb turbo 1979 fox...

[Bymguate]

Hey im new around here, currently in Guatemala city, new in the foxbody and mainly in the 4cyl draw thru pain.... Hahaha im pretty used to mega squirt, gm, and hp tunners side. Not the old stuff, but sold an fbody formula lt1 and got this awesome barn find in part of the payment.
Its a 1979 mustang 2.3t 4speed trans and the best is that its been well kept. Paintjob may be needed but never been crashed, has the original custom faided paint job.
The engine has been rebuilt 1000 miles on it. This friend wanted to rebuild it completely.

Since this is the only site that actually talks about the 4eyed carb turbo might aswell just join share and well get some help with the experienced buddies around here.
This is what i have installed, turbo timer, aem wideband, autometer boost gage, 2.5" custom down pipe dump in the rear end, choke butterflies deleted, smothed carb top, bmr rear control arms, and volvo electric fan. Initial timming in 10btc vac of while set, 7psi on mec fuel pump.

Heres where im stuck:
1) how does the duraspark retard timming "if it even does" on running operation? I know it retards to start the car... Or locking it would be the best option for a car that is ment to be driven daily? I feel it needs to rev a lot more, cant seem to feel boost, but a steady slow pull. And the car is harsh past 4500 rpms. When i think this is where it should start pulling hard.

2) How much boost will it handle, planing on only using 95oct, in the future either water injection or water/meth (if needed). Using a boost controller inside to boost higher if willing

Figured from different threads here the vacum madness, decided to delete everything and staying on basics: brake boster where the vac tree was, wastegate on the front manifold vac, and the distributor on the holley 5200 carbs side lower vac. No egr no nothing else but a/c and heater,

I had a bad issue that the carb leaned out in 3rd gear, was the float adjustment, pretty simple carb to mess with. Now having a steady safe 11:1 afr wot alk the way to high revs.

I dont want to take on the option just yet to make a blow through setup, or swap to the efi engine... If anything i would fabricate my own intake and exhaust with a bigger turbo and using a megasquirt... Just dont know if its worth it just yet.... And if this engine dies probably ill swap a 5.3 chevy instead .

Sorry bout the whole explanation but im quite exited on this light weight combo and want to build a little sleeper to have fun with...

[gr79]

The Duraspark module retards the timing using signals from the vacuum switch array mounted on the apron above it.
Manual basically says retards spark in steps every 2# of boost starting at 2#.
This can be 'locked out' but forgot how. It was unplugging a connector in the wiring.

Stock carb turbo engine waste gate is set to about 5# tops unless adjusted to allow more.
Overboost adds noticeable pull, but manual warns can damage things internally quickly no matter what.
Including using high octane.

A boost gauge will confirm boost levels. Cannot detect how much is there without one.
The green turbo light comes on at +1# or so.
The feel varies in relation to speed and gear.
Max boost comes on quickly at low speed/gear.
On highway, gradual pickup is felt and sustains.
When no boost happens, car runs like a regular 2.3.

Car in stock trim and good tune will pull or be as fast as a 80's V6 or a weak v8.
Even race when match racing a mid 80's Chevy Caviler Z24 2.8 LB6/auto (130 hp) for one.

Removing emissions or vac goofs up the way it runs.
Will pull to redline 6200. Will rev to 7200 but do not recommend this (did that once).
Boost starts about 2000 or less with a mild sustained push then a little more when cam kicks in around 3k.
Harsh high revs are for keeping engine in power band during shifts. No real power spike above 4000.

Certain conditions, boost can break the tires loose rolling in first and even in second to 'pedal it'.
Damp or dirty road surface? Easily spin tires. Blacktop too.

[Bymguate]

The Duraspark module retards the timing using signals from the vacuum switch array mounted on the apron above it.
Manual basically says retards spark in steps every 2# of boost starting at 2#.
This can be 'locked out' but forgot how. It was unplugging a connector in the wiring.

Stock carb turbo engine waste gate is set to about 5# tops unless adjusted to allow more.
Overboost adds noticeable pull, but manual warns can damage things internally quickly no matter what.
Including using high octane.

A boost gauge will confirm boost levels. Cannot detect how much is there without one.
The green turbo light comes on at +1# or so.
The feel varies in relation to speed and gear.
Max boost comes on quickly at low speed/gear.
On highway, gradual pickup is felt and sustains.
When no boost happens, car runs like a regular 2.3.

Car in stock trim and good tune will pull or be as fast as a 80's V6 or a weak v8.
Even race when match racing a mid 80's Chevy Caviler Z24 2.8 LB6/auto (130 hp) for one.

Removing emissions or vac goofs up the way it runs.
Will pull to redline 6200. Will rev to 7200 but do not recommend this (did that once).
Boost starts about 2000 or less with a mild sustained push then a little more when cam kicks in around 3k.
Harsh high revs are for keeping engine in power band during shifts. No real power spike above 4000.

Certain conditions, boost can break the tires loose rolling in first and even in second to 'pedal it'.
Damp or dirty road surface? Easily spin tires. Blacktop too.

Yeah i dont seem to see or even have the vacuum switch... Probably my timming wont retard and have excessive timming... Which in either case more timming and boost should pull harder (atleast theorically) unless its having excessive timming and im not being able to hear ping noise...

The car is boosting up to 10 psi, but wont even squick the tires at all... The only way it does is dropping the clutch around 4 or 5k stand still on first gear and still wont break traction.

And yes ive noticed this little turbo spools up pretty quick, specially since it has been modified to spool faster (what last owner said, when rebuilt). I can hear a turbo diesel spooling kinda sound when pushing the gas pedal around 2k rpm... That whistle hahahaha not the knock hahaha

So whats or where is the location of that vacumm stuff and which one is it... That way I can start fixing up before breaking up....

Cant seem to have bottom end torque aswell, checked the cam alignment with tdc and pulley mark in the window and seems its in its place.

[gr79]

The vacuum stuff is mounted above and forward of the turbo Duraspark box, which is a 3 harness version.
The extra harness controls the spark and is connected to the vacuum controls.
If the car was modded, no way to know whats going on.
Several pics of this assy are on this site.

Torque? I installed my cam straight up as i recall. Stock fine tune, carb, engine, turbo.
Set to 4-5# max boost.

Went for a long ride yesterday.
Car drives nicely in 3rd gear and 1200 rpm for slow cruising. That is 20 mph or 32kph
Can floor it from there with no buck or knock, and pulls steady.
Can hear the carb is wide open.
regular 87 octane fuel
The 2.3 carb turbo engine is capable of doing this without radical mods.

It can bark the tires shifting fast into 2nd on dry pavement. Spins thru 2nd very easily on wet.
Defiantly will lay rubber from a dead dig and say 2500-3000 launch.
Stock 3.45 rear gear, T-5 trans. 215/60/15 (25" dia) Firestones on Turbine rims.
Gosh i do not have the nerve to launch at 4-5k. Might break something.

Will creep over speed limits if not watching all the time.
It will peg the speedo at the tripmeter.
Never have tried to find max speed with GPS.

The spool up 'whistle' can be heard well, just before boost goes positive.
Depends on speed and gear how long the sound lasts.
Louder under load and higher speeds, inaudible floored from a traffic light.

[Bymguate]

The vacuum stuff is mounted above and forward of the turbo Duraspark box, which is a 3 harness version.
The extra harness controls the spark and is connected to the vacuum controls.
If the car was modded, no way to know whats going on.
Several pics of this assy are on this site.

Torque? I installed my cam straight up as i recall. Stock fine tune, carb, engine, turbo.
Set to 4-5# max boost.

Went for a long ride yesterday.
Car drives nicely in 3rd gear and 1200 rpm for slow cruising. That is 20 mph or 32kph
Can floor it from there with no buck or knock, and pulls steady.
Can hear the carb is wide open.
regular 87 octane fuel
The 2.3 carb turbo engine is capable of doing this without radical mods.

It can bark the tires shifting fast into 2nd on dry pavement. Spins thru 2nd very easily on wet.
Defiantly will lay rubber from a dead dig and say 2500-3000 launch.
Stock 3.45 rear gear, T-5 trans. 215/60/15 (25" dia) Firestones on Turbine rims.
Gosh i do not have the nerve to launch at 4-5k. Might break something.

Will creep over speed limits if not watching all the time.
It will peg the speedo at the tripmeter.
Never have tried to find max speed with GPS.

The spool up 'whistle' can be heard well, just before boost goes positive.
Depends on speed and gear how long the sound lasts.
Louder under load and higher speeds, inaudible floored from a traffic light.

So basically if this vacuum stuff was unistalled it wont retard spark whatsoever right? Cause i rather if it does not and use an msd btm to manage it myself....

I think i could have some cam, crank and distributor alignment problems... Since found that the best way the car has runned is at 30btdc.. with vacuum unpluged... Probably hitting really high numbers and still no knock or ping or whatever... Even having the btm installed and managing 0 degres per psi...

I dont really like the duraspark stuff apparently haha. Back to basics

[gr79]

If module timing retard harness is disconnected, well, timing will stay put.
Or in other words, not be retarded under boost by the box.
I guess this is done internally inside the Duraspark.

[Bymguate]

If module timing retard harness is disconnected, well, timing will stay put.
Or in other words, not be retarded under boost by the box.
I guess this is done internally inside the Duraspark.

I think it should do it internally, but it would need a reference, which comes to the question i had, how does a boost reference be activated by vacuum... I mean they are opposites... It doesnt make any sense to me hahahaha

[gr79]

Those sensors purpose is to translate vac signal to electrical.
Or convert one type signal or reference to another.
One language to another.

http://www.counterman.com/understanding-engine-sensors/

[Bymguate]

Oh yeah i get that. But how does vac relate to boost to decrease timming per psi? I mean you get the most vac with throttle closed, wot throttle means less vacuum, since its balancing with atmospheric pressure, the only vac you could see in wide open throttle situations would be the same restriction in the manifold and carb it self.... Boost means cero vacuum, once its over atmospheric pressure can be considered boost... unless its trigered by that low vac it wouldnt make any sense at all to me... Well might aswell figure out a way to control all that crap myself hahahahaha no wonder why this cars never freaking worked as expected... Any ideas on how to lose the duracrap for cheap?

[gr79]

yes vacuum (negative air pressure) then 0 then boost (positive air pressure)

Shop manual calls it boost pressure activated spark retard system.

Pressure switch assy (3, on bottom row of bracket)
Dual mode ignition module
wiring, etc

test procedure per Ford shop engine manual section SSD-34 part III:
connect external tach
remove pressure supply line to bottom 3 switches and plug
connect external pressure source tool to switches
remove and plug vac adv line at dist
warm up engine and fix engine speed to 1300-1400 rpm
apply vac slowly to assy

psi rpm decrease
0 to.49 0
.05 to 1.0 at least 100 rpm
1.0 to 3.74 no additional change
3.75 to 4.25 at least 100 rpm
release pressure engine speed should return to 1300-1400
to 0

do not know how to make the system work any cheaper than stock
aftermarket has options like MSD with boost control
know nothing about it other than it exists

far as i figure, all these things do is try to prevent spark knock using regular fuel by backing off timing on boost.
And allowing regular timing advance when driving off boost.
using the tech available at the time.

[Bymguate]

yes vacuum (negative air pressure) then 0 then boost (positive air pressure)

Shop manual calls it boost pressure activated spark retard system.

Pressure switch assy (3, on bottom row of bracket)
Dual mode ignition module
wiring, etc

test procedure per Ford shop engine manual section SSD-34 part III:
connect external tach
remove pressure supply line to bottom 3 switches and plug
connect external pressure source tool to switches
remove and plug vac adv line at dist
warm up engine and fix engine speed to 1300-1400 rpm
apply vac slowly to assy

psi rpm decrease
0 to.49 0
.05 to 1.0 at least 100 rpm
1.0 to 3.74 no additional change
3.75 to 4.25 at least 100 rpm
release pressure engine speed should return to 1300-1400
to 0

do not know how to make the system work any cheaper than stock
aftermarket has options like MSD with boost control
know nothing about it other than it exists

far as i figure, all these things do is try to prevent spark knock using regular fuel by backing off timing on boost.
And allowing regular timing advance when driving off boost.
using the tech available at the time.

Awesome info....
Since i dont have this boost pressure activated switch any more, i supose the duraspark works as a normal one that wont retard spark whatsoever...
I did install a msd (vortech boost timming master) which can be used without the msd amp... and can be plugged to the stock system... Basically it gets the ground signal to the coil coming from the duraspark harness and it retards timming based on a boost reference on it..you can chose from 0 to 3 degrees retard per psi... Up to a total 15 degree retard in spark... So if i set this on 1 degree per psi it will retard if i have 10 psi 10 degrees... If i set it up in 3 degrees per psi till a max retard of 15 degrees... Basically on almost 5 psi it will retard its max...
Im going to figure my initial timming issues and check everything is marked down correctly... Ill advance till ping starts.. then ill start reducing with the knob... Probably looking for 15 psi if fuel and air cleares them. Not having great hopes on holley 5200.... Probably looking for more cfm... Seems quite small for a boosted 2.3 imho.. maybe if it was an all motor engine but suckint air from That small carb seems more like a huge restiction. 350cfm seems like a better neighborhood...

[gr79]

I agree about the stock carb. Few alternatives (at least for daily driving).
Holley 350 cfm progressive would be fun to try. Wish i got one when they were available.
Once upon a time:
https://fordsix.com/viewtopic.php?p=220465

http://i23.photobucket.com/albums/b3...olley_2305.jpg

Maybe someday someone will figure out how to setup dual progressive 5200's.
Now would that be something or what? 4 total barrels opening up one at a time.
Prob would be simpler to spray a little nitrous. Heard that works well with turbochargers.

Yes the msd timing master from what i understand does the same thing and/or more as the factory setup.

You sure you want to go 15# boost with a carb turbo engine?
The engine under boost would have like way over 12:1 compression or cyl pressure.
Unless it has the later lower compression pistons, is too much and will blow up.

The McLaren modded carb turbo engines go to 7-10 as the posts here say.
Boy that's at the upper end with 9.0+ compression vs the 8.0+ for the later EFI turbos, which can take much more boost.

[Bymguate]

I agree about the stock carb. Few alternatives (at least for daily driving).
Holley 350 cfm progressive would be fun to try. Wish i got one when they were available.
Once upon a time:
https://fordsix.com/viewtopic.php?p=220465

http://i23.photobucket.com/albums/b3...olley_2305.jpg

Maybe someday someone will figure out how to setup dual progressive 5200's.
Now would that be something or what? 4 total barrels opening up one at a time.
Prob would be simpler to spray a little nitrous. Heard that works well with turbochargers.

Yes the msd timing master from what i understand does the same thing and/or more as the factory setup.

You sure you want to go 15# boost with a carb turbo engine?
The engine under boost would have like way over 12:1 compression or cyl pressure.
Unless it has the later lower compression pistons, is too much and will blow up.

The McLaren modded carb turbo engines go to 7-10 as the posts here say.
Boy that's at the upper end with 9.0+ compression vs the 8.0+ for the later EFI turbos, which can take much more boost.

Yeah that dual carb setup would look nice but double the trouble.... i was thinking on the 350cfm holley exactly
Im not afraid of boost... If you keep a steady safe afr and timming you can work with high boost easy. Ive built couple of non turbo engines with turbo/s (ls2 15psi, ls1 10psi, 5.3 20psi, lt1 13psi, and well some other older models like the typhoon 4.3 boosting up to 25) all of them with stock compression, stock bottom ends and so on... All of them working nice for quite a while.
Biggest problem on people who like to boost up is that they do not match stuff to work for it... Afrs and timming specially... Melting pistons is an afr problem, keeping a low 12:1 is a safe side, having the right timming will keep rods and pistons breaking... Everything has its limits obviously, as far as i know the efi engine has the same block and crank, they did lower compression and that can take better boost, doesnt mean it wont break if afrs are off or timming is way to high.... but then again i dont mind breaking everything and do the swap works.... Hahhahaha