'66 Slant Six Turbo Build

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I'm curious about how you're referencing fuel pressure to boost. You need to maintain 4-7 psi above boost pressure for the carb to function. I did an article on Allpar a couple years ago that covered referencing the breather port on the fuel pump to above-carb boost (See the Holler Help section, don't know if I can post links before racking up posts).

Secondly, you must retard timing. I used the MSD-BTM which worked out very well. It's tunable, degrees per psi boost, when it kicks in, etc.

It looks to die for, to say the least. Awesome work!

Mike
 
I'm curious about how you're referencing fuel pressure to boost. You need to maintain 4-7 psi above boost pressure for the carb to function. I did an article on Allpar a couple years ago that covered referencing the breather port on the fuel pump to above-carb boost (See the Holler Help section, don't know if I can post links before racking up posts).

Secondly, you must retard timing. I used the MSD-BTM which worked out very well. It's tunable, degrees per psi boost, when it kicks in, etc.

It looks to die for, to say the least. Awesome work!

Mike

I'm using a mallory 4309 fpr. Its referenced right into the back of the intake manifold for a signal. It's set at 5 PSI right now and it rises 1:1 with pressure. I'm sure the initial setting may change once I get it on the dyno.

For the ignition I'm going to use an MSD 6530 programmable. That'll allow me to lock out the mechanical timing and run a custom curve. I'm also putting in a MAP sensor so I can retard for boost.

I be on the dyno by the end of the month if all goes well.
 
If you are connecting your FPR to manifold, is it possible that under vacuum you are getting less than 5 psi? Don't know the product.

Mike
 
Where in Az are you? You seem like a dude I would hang out with. Lol
 
Way Cool. Looks like its going to be a fun ride.

It is a very fun ride so far. I finally locked out the distributor today to get it ready for dyno day tomorrow. I took it for a spin today and built about 5-6 psi at about 1/4 throttle and man did it want to go!

Wish me luck tomorrow, I'm trying to get a smooth 15-20 psi out of it all said and done.
 
Just go done with the first round of dyno tuning.

Slant six + GT32 =

440.6 lbft @ 3808 rpm

and

330.7 Hp @ 4057 rpm

Not too bad! I haven't got her weighed yet but I think with some traction that'll make for a sub 12s time slip. No?

We could not get a full run to 5k or 5.5k rpms because of boost creep. The numbers above were at 16.5 psi and at that point we got a little ping that we could not tune out. AFR was about 9.5-10.5 down at 1k rpm and 12.7 when we hit peak torque. Slightly lean on top...

We're thinking we could fatten it up with a bigger jet to alleviate the ping but time ran out and it probably wasn't the best idea for low end power.

Anyhow, the turbo is internally gated so it needs to be machined out and bigger waste gate created. It is also a twin scroll with one side pretty much isolated from the waste gate. I might machine the scroll out a bit and open the circuit up to the waste gate. That will cost me some spool but it had 10 psi before 3k so it's spooling fast enough :-D

I'll get a scan of the dyno plot later on. I'm not terribly upset we could not get a full pass because at least we know how much power it can make - we probably only left 15-25 Hp on the table. Until I get the boost under control I will mix in av-gas for insurance.
 
Thats some crazy power/torque to the wheels man! Whats done to your cylinder head? What cam are you using?
 
Seems like a little low for 16.5psi. Did you have the head flowed? You might want to do a little more head work before you do too much on the turbo. Those numbers and rpms tell me it's choking.
 
Dyno plot:

IMAG0034_zps4e01c644.jpg


'66 on the Dynapack:

IMAG0030_zps0151a8b5.jpg
 
Seems like a little low for 16.5psi. Did you have the head flowed? You might want to do a little more head work before you do too much on the turbo. Those numbers and rpms tell me it's choking.


Hi moper,

Remember, I didn't reach my peak horsepower because of detonation. Once we can spin it up to 5200-5500 rpms we'll probably see 10-25 more horsepower.

Even so, looking at the /6 head compared to a modern head it could use a ton of work. It think the best bang for the buck in the future is going to be even bigger valves and more lift. I need to see how much lift I can get away with since I'm running the slugs about .035" below deck.

I think If I stepped up to a t3/60-1 or even t3/t67 I could get similar power around 10-12psi. The gt32 is pretty small, and needs a lot of pressure to move a lot of air.
 
cool build for sure and impressive numbers!

but i dont understand this: "The gt32 is pretty small, and needs a lot of pressure to move a lot of air."

Isnt the air flow first and then the pressure because of "too much airflow into a closed volume"?

Michael
 
cool build for sure and impressive numbers!

but i dont understand this: "The gt32 is pretty small, and needs a lot of pressure to move a lot of air."

Isnt the air flow first and then the pressure because of "too much airflow into a closed volume"?

Michael

I've always know flow in lb/min and pressure as two different things which are related.

PSI is measuring density and flow lb/min is how much air is moving through the system and how quickly. Flow lb/min is ultimately what determines your peak power.

A small turbo has to react to an engines appetite by increasing the density of air it puts out to keep the flow up with what the engine can flow. With my current setup if I port my head and open up my exhaust it will increase my VE, the engine will become more efficient and flow better, produce more exhaust, spin the gt32 better in effect pushing it to create more psi to keep up with the flow, however, since the system is running more efficiently there will be a bigger return on the pressure - more power. It's all related and all way to technical for me :mrgreen:

Conversely, if I just slap on a larger turbo that can move the same amount of air at 8-9 psi, like a gt35r then my peak power will remain similar if i make not other changes to increase my VE. The power band will shift but over all flow will remain comparable.

Have you ever taken a look at compressor maps? They help visualize what I'm saying here.
 
Hi moper,

Remember, I didn't reach my peak horsepower because of detonation. Once we can spin it up to 5200-5500 rpms we'll probably see 10-25 more horsepower..

Do you have forged pistons? How much total spark advance are you running, what octane gas, and what was your A?F ratio when you began to experience detonation.

Our engine is pretty similar to yours but with us running only 8 pounds of boost and using 110 octane gas (and 18 degrees of total spark advance) we haven't seen any detonation, yet.

Thanks a lot for all the good info!!!
 
Do you have forged pistons? How much total spark advance are you running, what octane gas, and what was your A?F ratio when you began to experience detonation.

Our engine is pretty similar to yours but with us running only 8 pounds of boost and using 110 octane gas (and 18 degrees of total spark advance) we haven't seen any detonation, yet.

Thanks a lot for all the good info!!!

Hi Bill,

Yes, the engine has forged pistons.

Total timing is at 38, under boost the msd box is pulling a a degree per pound up to a bar and 1.5 degree past a bar, based on the reading from the MAP sensor.

Essentially, under 16.5 psi we should end up pulling about 18.5 degrees for timing of 19.5.

Now we also have a out of boost map that gives us a smooth ramp to 4.5K rpms to total timing of 38, we're pulling a lot before 1.5K. No problems out of boost though of course :)

At this boost we were only at 4,000 rpms and the AF/r was 12.7 - getting too lean. I need to figure out how to keep the boost down, at full rpms we would probably see 18psi+

Until I can get to the dyno again I'll probably set the total timing to 36 to dial everything back 2 degrees, that would give me 17.5 degrees at 16.5psi. Meanwhile I'm getting a little miss between 3.5-4K rpms that wasn't there yesterday, I may have fouled a plug already - we used a NGK 8 heat range because I didn't have any 6 or 7s available.

We'll see... Tons to play around with now :-D
 
Hi Bill,

Yes, the engine has forged pistons.

Total timing is at 38, under boost the msd box is pulling a a degree per pound up to a bar and 1.5 degree past a bar, based on the reading from the MAP sensor.

Essentially, under 16.5 psi we should end up pulling about 18.5 degrees for timing of 19.5.

Now we also have a out of boost map that gives us a smooth ramp to 4.5K rpms to total timing of 38, we're pulling a lot before 1.5K. No problems out of boost though of course :)

At this boost we were only at 4,000 rpms and the AF/r was 12.7 - getting too lean. I need to figure out how to keep the boost down, at full rpms we would probably see 18psi+

Until I can get to the dyno again I'll probably set the total timing to 36 to dial everything back 2 degrees, that would give me 17.5 degrees at 16.5psi. Meanwhile I'm getting a little miss between 3.5-4K rpms that wasn't there yesterday, I may have fouled a plug already - we used a NGK 8 heat range because I didn't have any 6 or 7s available.

We'll see... Tons to play around with now :-D

Count me among the ones who think that you have done an EXCELLENT job with this build!!! There are so many pitfalls, blind alleys and dead end streets to go down, doing this... and it looks to me like you have avoided all of them.

I am impressed!

I'd like to know how much the car weighs and something aboiut your chassis tuning. If it's as good as the engine tune, it's gonna HOOK!!!

Thanks again for all the goood information!

Keep us posted; I want to see how much boost it takes to get that little jewell into the elevens!!!!:blob:
 
Hi Bill,


Total timing is at 38, under boost the msd box is pulling a a degree per pound up to a bar and 1.5 degree past a bar, based on the reading from the MAP sensor.

Essentially, under 16.5 psi we should end up pulling about 18.5 degrees for timing of 19.5.

:-D

One question: The MSD website says, "The Boost Timing Master allows you to adjust the amount of ignition retard from 1° per pound of boost to 3° per pound via a control knob that you mount on the dashboard. This way you can make adjustments on the fly to prevent detonation as fuel quality or altitude and air quality changes up to a maximum of 15° retard."

If you are running 38 degrees total, and the Boostmaster retards it 15 degrees (which is the most it can retard it, according to their ad,) you end up with 38 minus 15, or 23 degrees of advance.

That's about 5 degrees too much. Is there some other retard feature that I don't know about that you are using? If not, could that detonation you expereienced be due to that 23 degrees of advance?

I obviously don't understand how you're getting 18 degrees with this setup.

Please let me know... I have one of those Boost Timing Masters on my supercharged 360 Magnum engine in my '72 Valiant.

Thanks for any information!!!
 
First - I'm not a big boost guy....lol. But in regard to this passage:
"I've always know flow in lb/min and pressure as two different things which are related.
PSI is measuring density and flow lb/min is how much air is moving through the system and how quickly. Flow lb/min is ultimately what determines your peak power."

I'm not sure it I agree. As I understand it "flow" is the output of the turbine. It's dependant on the rpm of the shaft (the exh side) and the compressor side size and design. PSI is the measurement of the resistance of the intake tract to that flow. A great port will indicate less PSI than a bad port with the same compressor being spun at the same speed. It seems to me that the port is way restrictive (which fits every '6 peice I've read...lol) and you're blowing a lot through it. That may be messing with the signals the carb's getting and giving you the lean condition too.
I'm still in a learning curve for these engines but I'd definately look to make the ports work better. It will help with any turbo upgrade later.
 
One question: The MSD website says, "The Boost Timing Master allows you to adjust the amount of ignition retard from 1° per pound of boost to 3° per pound via a control knob that you mount on the dashboard. This way you can make adjustments on the fly to prevent detonation as fuel quality or altitude and air quality changes up to a maximum of 15° retard."

If you are running 38 degrees total, and the Boostmaster retards it 15 degrees (which is the most it can retard it, according to their ad,) you end up with 38 minus 15, or 23 degrees of advance.

That's about 5 degrees too much. Is there some other retard feature that I don't know about that you are using? If not, could that detonation you expereienced be due to that 23 degrees of advance?

I obviously don't understand how you're getting 18 degrees with this setup.

Please let me know... I have one of those Boost Timing Masters on my supercharged 360 Magnum engine in my '72 Valiant.

Thanks for any information!!!

Hi, Bill

I'm using the MSD 6530 programmable 6al-2. It allows us to pull up to 25 degrees out.

And I wish I had the chassis setup as good as the engine! It's doesn't hook for anything right now. I can put it into boost on the highway and it can spin the wheels and bounce around - not good.

Anyhow, it's just a stock 8 3/4 clutch type sg with 2.76 gears. Running mancini xhd leafs and kyb shocks. Little baby 225/60-14 bfgs. The tranny is a 904 with a shift kit and a 1.8K stall converter, I might need to bump that to a 2.2K or maybe even higher... I think what I want to do for tires is a spring relocation and run a 16" or 17" with between 275/45 or 275/55 then I want to get some good adjustable drag shocks.
 
Did you use the 'off the shelf' Wisecos?

No, they were custom ordered, I forget the exact specs off the top of my head. I could back into them again or find my purchase order - specifically talked to the wiseco guys to get the best alloy for boost. I used this article as my basis:

http://www.slantsix.org/articles/stroking/stroking.htm

I wanted them to be similar to the KB268 to be near zero deck for a good squash zone.
 
First - I'm not a big boost guy....lol. But in regard to this passage:
"I've always know flow in lb/min and pressure as two different things which are related.
PSI is measuring density and flow lb/min is how much air is moving through the system and how quickly. Flow lb/min is ultimately what determines your peak power."

I'm not sure it I agree. As I understand it "flow" is the output of the turbine. It's dependant on the rpm of the shaft (the exh side) and the compressor side size and design. PSI is the measurement of the resistance of the intake tract to that flow. A great port will indicate less PSI than a bad port with the same compressor being spun at the same speed. It seems to me that the port is way restrictive (which fits every '6 peice I've read...lol) and you're blowing a lot through it. That may be messing with the signals the carb's getting and giving you the lean condition too.
I'm still in a learning curve for these engines but I'd definately look to make the ports work better. It will help with any turbo upgrade later.

Great head porting will make the whole system more efficient, it will allow more flow, create more power. As far as I understand the only thing that will significantly increase the PSI at the compressor is more exhaust flow spinning the hot side. Thus, more lift, bigger exhaust, better ports will only increase pressure because it will allow more flow, consume more fuel and create more - faster moving, exhaust.

If you think about it like a fluid system, peak pressure will not increase until energy is being applied to the system. If you load up a pipe with 20psi of water pressure it will not continue to rise unless more pressure is applied via a pump or piston or whatever.

In my case, the boost is rising because more exhaust flow is being applied than the turbo's little waste gate can bleed off. The waste gate controls the amount of exhaust gas/energy diverted from the turbine wheel, slowing the wheel down, keeping pressure under control.

Does that make any sense?
 
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