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Could one make this work? http://retrotekspeed.com/product.php?pk=52

That is a whole lot of cfm for a 2.5L.

The issues we faced with the Pinz EFI are faults of the bone stock engine, its configuration and space constraints- not any particular EFI system.

I drove the new plenum on Friday, I will finish the MP value tuning and drive it every day next week on my 83 mile daily commute... Then make my decision on the system's future as a product.

I keep the bar raised high for anything I develop.... So far the Pinz development with OVER two years of my development time just hasn't impressed me..

Its the engine, not the EFI-

Jake, I agree, But Efi would help with some of the maintance for use who are not mechanically incline nor want to be. My time is best spent at work, after that I like playing with the kids. having the valve checked every 6,000 miles is enough for me. i will work on the engine after it has give up and adapt something that is more reliable. like your cylinders.

And Jake Happy 232 To you

Erik,
Thanks for the Birthday wish!

There seems to be a common misconception about EFI, its probably being exaggerated by most of the advertisements of FI systems...

That misconception is that EFI systems that are programmable are going to create an engine that is just as trouble free as a brand new 2007 vehicle- Not happening.

With EFI systems (I have used 15 different base ECUs) there IS A LEARNING CURVE that cannot be avoided. Tuning of the system is still a reality. That tuning isn't simple.

The facts are, (and I word this VERY BOLDLY):
If you have difficulty with carb tuning and understand hundred year old simple carburator technology you will have an even more difficult time with the required EFI learning curve. IF you do not set the system up correctly and get it tuned perfectly the engine can be MORE difficult to work with than with those simple carbs.

This huge misconception and the fact that I believe a lot of people are "over expecting" what EFI really is, has made a big impact on my EFI kit..... The kit that I have worked to make a true bolt on-

The day we wake up to a perfect world is the only day that a 40 year old engine will be modernized to the point of a 2007 Hummer... Don't ever expect it to be.

Sorry, thats just the facts and even though the EFI ECU that I have used is the most simple in the world to tune and set up it still has sub systems that require perfect function to be effective..

And you have to have patience....

This system looks more interesting to me-
http://www.retrotekspeed.com/products/n ... x2-tb-kit/
They look like they'd be similar size to the carbs and could probably bolt to the existing intakes with a simple adapter plate. The system might gain a few mpg and get rid of the notorious stumble

From what I've seen from Jake and Jim, it looks like the key to real horsepower is to open the engine and start at the begining- higher compression, re-worked cam, bigger valves, etc. The Austrians intentionally designed an aircooled engine that is indestructible in the hands of recruits and works over a range of altitudes and temperatures, not necessarily one that is the most efficient or makes the most HP.

Yes, The Austrians seriously optimized the bone stock combo. It took me over a solid month and 60 gallons of fuel on the dyno to ever beat the optimized carbureted set up and even then I didn't even beat it by 5%...

To optimize the engine for the new millenium, or make EFI worth it's investment requires a different internal engine combination. I began working on my version of this second generation engine before I even owned a Pinzgauer and have modified my plans based on the results I have personally experienced over the past two years.

Cam, head and CR alterations are the key... What I learned is you can't beat the Austrians with only bolt on components and no internal mods.. I failed at even equaling the stock carburetor performance 95% of the time when swapping components.. Hell even changing to a K&N air filter from the stocker dropped torque by 15%!!! This includes swapping any part from the stock configuration including exhaust and then swapping ALL these parts in association with each other and beating my head against the wall..

Now keep in mind that one can take a 40 year old bone stock VW engine, swap just the exhaust and pick up a 20% power gain..... I have done that dozens of times!

The Pinz has one hell of an engine, just don't expect to beat the Austrians and don't expect EFI to be a magical transformation of a 40 year old vehicle... Hell in my lab tests we were calculating much more than just HP, based on the brake specific fuel consumption the carbs also proved to make a more efficient engine in all the tests with anything but our most recent version of the intake plenum! We were testing for much more than just TQ and HP!

I'll be driving mine with V4 of the EFI system recently optimized in my lab everyday this week, unless it seriously impresses me with MPG and running temps/smoothness I'll be accepting the first ever developmental failure I have ever experienced from such a comprehensive approach and total concentration of effort...

That pisses me off.

Sounds like you have really tried your hardest Jake, but time and time again, I've realise that:

"The Engineers and Designers at SDP (guys below) DEFINITELY knew what they were doing!"

NC_Mog wrote:That is a whole lot of cfm for a 2.5L.

CFM can be misleading, you have to realize you are dealing with Independent Throttle Body (ITB) systems. Unlike a normal carb/throttle body where the CFM is spread over all cylinders, the ITB has to be sized for peak flow, not average. So the bore diameters are a bit larger than what you would do for an engine with a plenum below the throttle plate.

When folks say the 36mm stock pinz carb is oversized they are falling for that same issue as well. They are properly sized.

The concern with using the various ITB bolt on's like the one mentioned is the bore and spacing of the pinz is fairly unique. There were some weber adapters which were close, but you'd end up with some odd air restrictions on the adapter plate.

Have fun,

Alan

MASSIVE PINZ wrote:The issues we faced with the Pinz EFI are faults of the bone stock engine, its configuration and space constraints- not any particular EFI system.

While I know what you are saying, I balk a bit at using the term "faults". It's really more of constraints imposed by the mission/design constraints.

The pinz has an extremely flat torque curve, and a fairly flat HP curve. Such that many small diesels would not offer a huge advantage.

It was never intended to be a high HP, high rev engine, so what many would consider constraints/faults I believe are purpose built engineering!

To get that you find out the designers did several odd things, many of which defy traditional performance improvements:

- Bizarre cam timing
- odd intake port shape/size
- intake runner sizing (diameter/length) sub-optimized based on theory. Way to fat for the HP/flow required. Way too short.
- Unequal intake runner lengths
- Independent Throttle body (one throttle plate per intake) & carb sizing

None of these by themselves make or break, but I've come to realize that all of these together contribute to the flat torque curve, etc. IE: None are accidents.

When you see how the factory engineers fitted k-jet mechanical FI, they did some very specific things to maintain these characteristics. It was not a bolt on application from another vehicle, it was completely customized to the pinz engine dynamics. (far more than just plumbing)

Not to second guess Jakes work, I had hoped a plenum based approach would work. Jim's seems to have. But I'm convinced:

- ITB's will be easier to make work from an engine dynamics perspective. minimizes the plenum effects, which has to be complicated on the pinz due to the unequal length runners, firing order, etc. Having the throttle body at the end of the plenum makes it more complicated (but not unworkable, production cars do it)

- ITB's offer a bit more flexible tuning of the airflow, and should result in more equal air flow to each cyl. The ones I have actually have a 2nd small throttle plate I plan to use for this.

- I see the factory intake as one of the major constraints. Expensive, very difficult to modify. Not particularly efficient from a flow perspective. (But specifically sized I suspect)

- I'm with jake at not having the injectors down low. that's an emission thing, not a power thing. The idea that injectors have to shoot on the valve is a myth. It does help emissions, but really works against you on many engines for power/torque. (Hint: atomization is better than vaporization) High HP corvettes had injectors shooting into runners at 90 degrees several inches from the valves for many years without any problems! No shortage of power gain over carbs. F1 cars use ITB's with injectors above the throttle plates! The only concern might would be icing, but with the pinz airflow I don't see that as a huge concern.

- This means more complicated plumbing. I've had flanges waterjet cut for the intake with the idea of experimenting with runner lengths, etc. Lot's of constraints with the pinz doghouse. But there is room for motorcycle ITB's.

- I'm planning short stubs on the flange which can be joined via silicon boots to the runners of the day for testing so I don't have to fab & bolt/unbolt the intakes each time I change. This is not uncommon on race vehicles and production cars, it's a valid approach. The pinz is not a high CFM beast anyway, and even with the gap, using smooth tubing will have less drag than the factory cast iron.

- You'd then have to decide whether to equalize the runner length, or give the SDP engineers benifit of doubt and leave them unequal! Based on Jake's learnings my gut is that it's not by accident, they could have just as easily made the runners equal length.

- ITB's will be more involved to control from a throttle cable perspective unless you use one the the motorcycle ganged ITB's. But that does come with more flexibility in air equalization.

My read on the varying cyl temps Jake saw was plenum dynamics resulting in differing airflow. I'm sure he had the fuel nailed down well. The odd valve timing and super short runners I believe magnify normal plenum issues.

One thing I was not surprised at was that the induction side (air horn & filter) was not a constraint, nor was the exhaust. These both were well sized for total engine flow, and the SDP engineers would not have compromised there. (Unlike VW and MazToyoSan in the early years)

Again, I'm very sorry Jake has encountered as much difficulty. We all hoping for the magic bullet, so to speak. I'm convinced it's still worth pursuing, but as Jake indicates, it will be tougher to beat the factory and maintain mission suitability.

Jake, I'll ship you some waterjet cut intake flanges and properly sized motorcycle ITB's if you want to give it a try! Just some tubing mandrels and welding needed! And another hundred hours of dyno time, who knows.

Have fun,

Alan

What is ITB's?

Individual Throttle Body

Of course, I had to do some google searching to figure that out....

While I know what you are saying, I balk a bit at using the term "faults". It's really more of constraints imposed by the mission/design constraints.

When a constraint effects my manipulation of an engine while working under certain parameters I consider it a "Fault" that limits the use of more modern theory to reach the objective.

The pinz has an extremely flat torque curve, and a fairly flat HP curve. Such that many small diesels would not offer a huge advantage.

Absolutely correct, it's flat but also very short with the MAX HP we ever made during the testing being at 4,100 RPM and change.

It was never intended to be a high HP, high rev engine, so what many would consider constraints/faults I believe are purpose built engineering!

Yes, but when trying to stretch the RPM range out a bit for better all around performance on the street and off road it is very disappointing to settle for such a short RPM range. My developmental experience has shown that keeping the torque curve flat but moving the peak TQ up a bit to make it closer to the optimum cruise speed is essential for gas mileage. The reason the Pinz gets crappy mileage is the fact that it operates so much higher over the peak TQ RPM when cruising at anything close to modern speeds, even with taller tiires. By keeping the torque curve flat and only accentuating the range that torque is made I have time and time again made cooler running, more usable, better MPG creations.

To get that you find out the designers did several odd things, many of which defy traditional performance improvements:

Its not just that they defy conventional PERFORMANCE improvemments, but that they all defy the era of thought that was general unde3rstanding by auto designers around the world at the time for both stock and race engines.

- Bizarre cam timing

-
The only bazaar cam attribute is the lobe centerlines and the fact that I haven't measured two cams yet that were the same!! The camshaft in the engine I used for lab testing is NOT THE SAME as the unit in my '73, 710M.

odd intake port shape/size

It's similar to the Porsche 911 2.0 engine, just a tad smaller.

- intake runner sizing (diameter/length) sub-optimized based on theory. Way to fat for the HP/flow required. Way too short.

Actually I consider the Pinz runners more than adequate length for the intended application when coupled to the 32 NDIX carb. When these carbs are used on a 356 engine the manifolds are 1/2 the length of the Pinz manifolds.

- Unequal intake runner lengths

Yes, this is bazaar and can be seen in the exhaust gas temp differentials across the engine clearly... I don't understand this one at all.

- Independent Throttle body (one throttle plate per intake) & carb sizing

At the time this was the best way to increase down low torque without creating huge flat spots. A common plenum would have more than likely been hard to fit and would have compromised the throttle response at heavy load and low RPM- not good.

None of these by themselves make or break, but I've come to realize that all of these together contribute to the flat torque curve, etc. IE: None are accidents.

Absolutely and it goes right down to the exhaust system and muffler, from the intake to the tail pipe this engine is one "combination".

When you see how the factory engineers fitted k-jet mechanical FI, they did some very specific things to maintain these characteristics. It was not a bolt on application from another vehicle, it was completely customized to the pinz engine dynamics. (far more than just plumbing)

I use K jet on my VW Bus engines and LOVE it, but fitting it to a Pinz was ggoing to be way difficult and I realized that early on.

Not to second guess Jakes work, I had hoped a plenum based approach would work. Jim's seems to have. But I'm convinced:

I used the same plenum that Jim has in the second stage of my testing, it didn't work well at all when compared to the carbs or the other 3 plenums we compared it to.

In the truck my first and second generation arrangements also seemed to work, but when actually scientifically compared the changes were within the measurable accuracy of my dyno time and time again. In the truckj you can't tell whats going on nearly as much due to the weight and gearing. Creating one baseline to compare things to was the difference that gave me tons of insight, and information that I am sure no one else has attained before me.

- ITB's will be easier to make work from an engine dynamics perspective. minimizes the plenum effects, which has to be complicated on the pinz due to the unequal length runners, firing order, etc. Having the throttle body at the end of the plenum makes it more complicated (but not unworkable, production cars do it)

I had attempted to do this and use the stock carbs as throttle bodies, or have Jenvey Dynamics make me some Pinz specific throttle bodies. I work with them all the time and i am sure they'd do it. The cost was 1500 bucks/set when purchasing them 20 pair at a time!

- ITB's offer a bit more flexible tuning of the airflow, and should result in more equal air flow to each cyl. The ones I have actually have a 2nd small throttle plate I plan to use for this.

Yes, but at the cost of tedious synchronization and more throttle shaft bushings and plates to wear.

- I see the factory intake as one of the major constraints. Expensive, very difficult to modify. Not particularly efficient from a flow perspective. (But specifically sized I suspect)

On the flow bench the stock head picked up CFM and velocity with the intake added, not till we added the carb did we see a drop in gross CFM @ 28" depression. My 3.3 is using the stock runners with intake ports that are 30% more effective and I feel it'll be fine for the intended RPM range.

- I'm with jake at not having the injectors down low. that's an emission thing, not a power thing. The idea that injectors have to shoot on the valve is a myth. It does help emissions, but really works against you on many engines for power/torque. (Hint: atomization is better than vaporization) High HP corvettes had injectors shooting into runners at 90 degrees several inches from the valves for many years without any problems! No shortage of power gain over carbs. F1 cars use ITB's with injectors above the throttle plates! The only concern might would be icing, but with the pinz airflow I don't see that as a huge concern.

-

I got the data back to back with both inkjector positions using all the different plenums. The difference was extreme and the biggest difference we saw during all the testing. My MKIII injector position was the absolute best we tested having the best power, lowest accelerator pump settings needed to overcome off idle hesitations as well as liking lower MP and RPM fuel values in the ECU (indicating more efficiency) and the coolest running, most stable temperatures

This means more complicated plumbing. I've had flanges waterjet cut for the intake with the idea of experimenting with runner lengths, etc. Lot's of constraints with the pinz doghouse. But there is room for motorcycle ITB's.

Yes and several will fit and work OK, but it won't be a bolt one and that was the goal of my development.

- I'm planning short stubs on the flange which can be joined via silicon boots to the runners of the day for testing so I don't have to fab & bolt/unbolt the intakes each time I change. This is not uncommon on race vehicles and production cars, it's a valid approach. The pinz is not a high CFM beast anyway, and even with the gap, using smooth tubing will have less drag than the factory cast iron.

The pinz engine has INSANE manifold pressure at higher RPM on deceleration and at idle. This could cause the tubing to be collapsed during high negative manifold pressure. Race engines typically have long duration cams and not much dynamic CR, greatly reducing their manifold pressure at idle and deceleration. A good example is at idle, most of my performance VW and Porsche engines idle at -9-11MP, the Pinz engine

idles at a whopping TWNENTY FOUR TO TWENTY SEVEN!!

- You'd then have to decide whether to equalize the runner length, or give the SDP engineers benifit of doubt and leave them unequal! Based on Jake's learnings my gut is that it's not by accident, they could have just as easily made the runners equal length.

But an equal length runner would have made the carbs sit unlevel in the truck on flat ground due to the engine's incline...

- ITB's will be more involved to control from a throttle cable perspective unless you use one the the motorcycle ganged ITB's. But that does come with more flexibility in air equalization.

And throttle cable fitting is also a challenge. I overcame it pretty easily with the V3 plenum.

My read on the varying cyl temps Jake saw was plenum dynamics resulting in differing airflow. I'm sure he had the fuel nailed down well. The odd valve timing and super short runners I believe magnify normal plenum issues.

Yep... And exhaust system design/configuration.

One thing I was not surprised at was that the induction side (air horn & filter) was not a constraint, nor was the exhaust. These both were well sized for total engine flow, and the SDP engineers would not have compromised there. (Unlike VW and MazToyoSan in the early years)

I was expecting the exhaust to make big changes and was disappointed when my hypothesis was totaly wrong!

Again, I'm very sorry Jake has encountered as much difficulty. We all hoping for the magic bullet, so to speak. I'm convinced it's still worth pursuing, but as Jake indicates, it will be tougher to beat the factory and maintain mission suitability.

But is is suitable as a bolt on that can be done by the general person that owns one of these trucks??? If I would have never taken the time to do the lab portions of my tests I would have been fooled into believing that it was.

Jake, I'll ship you some waterjet cut intake flanges and properly sized motorcycle ITB's if you want to give it a try! Just some tubing mandrels and welding needed! And another hundred hours of dyno time, who knows.

Have fun,

I am done with the stock engine, all my efforts now are going toward a redesign of the combination with the 3.3L engine and seeing if I can kick the Austrian's asses that way!

Just when I was ready to dith the whole idea...

I have been driving the Pinz around for the past week with the system "as dynoed" making small changes to the fuel map..

Once I corrected some low speed tuning challenges that we could not "feel" on the dyno I decided to take the truck off road..

What I experienced made all the work actually worth it! The truck could lubg down much lower and have immediate throttle response! No hesitations, no lags, no misfires, no black smoke out the tailpipe!!

So, this makes a huge impact on my decision regarding the system since most Pinz owners use the truck for offroad and thats exactly where the system shines with the plenum alterations.

Final details by December 1..
I finally smiled about this development