NA 3.1L=>head & camshaft questions. No shortcuts, max

[madkaw]

Sounds a little like my last dyno shop experience. Not going thru the whole story but in the end the owner said he had found a niche market catering to Lotus crowds and really didn't care about any other business. This was very much different from my first visit with the guy; maybe cash was greener then?

It does suck to have so little data -especially AFR. 

On my last run the operator said I was almost dangerously lean(14) at WOT, contrary to my 13.1 I was showing on my gauge. He also stated earlier that his tail pipe sniffer might read lean? So what am I to believe?

Going with a different dyno next session 

[zredbaron]

Humm..Well written. What were your specific goals to accomplish while there? Besides tune?

 

Thank you, Steve.

 

My goals were to collect and compare A/F ratio, torque and power plots for the following on the same engine, same dyno, same day:

• 40DCOEs w/36mm venturis
• 45DCOEs w/36mm venturis
• 45DCOEs w/38mm venturis
• 45DCOEs w/40mm venturis

My purpose was to confirm venturi selection, and my R&D desires were hopeful the data would back up my "stalled carburetor" theories (the 40DCOE). This is not possible to confirm or deny without an A/F graph. The BSFC was an unexpected bonus to aid this research, but it's useless by itself. For my application, anyway....

 

In short, because Arnie and I miscommunicated, the internet still does not possess such a comparison to the best of my knowledge. Upset me greatly. It's entirely possible I would not have found an alternate, in which case nothing was lost. I did not have such a choice, as I had already "confirmed" his shop met my needs. It didn't.

Edited March 22, 2017 by zredbaron

[JMortensen]

For my part, I'll say that it did seem that Arnie was perturbed by the fact that you wanted to run the 40s and then the 45s. Also surprised me how much time it took to change things between pulls. Between swapping the carbs and putting the freeze plugs back in, there wasn't a whole lot of time for carb tuning. I think there were 2 or 3 jet changes and the one venturi change on the 45s and that was basically it. I think you would have done a lot better if that freeze plug issue hadn't hampered progress. You didn't really explain that, so I will.

 

They were running the engine with no alternator, but needed the coolant to circulate so there was a belt going from crank pulley to water pump pulley. No tensioner. The belt that they were using was just a bit loose, so you could see it flopping around when the pulls were going. I can't remember how many times (3 or 4) a freeze plug would exit the block and make this surprisingly loud "Booooosh!" sound, then Arnie would cut the power to the engine and steam would be everywhere, etc. Every single time it happened I thought there was a hole in the block or some other catastrophic failure. It was a really loud noise that it made. There is a plug under the timing cover too, so we were all worried that if that one popped it would take hours to fix. Mark finally suggested a tighter belt, based on the theory that the belt was catching and slipping and this pulsing of pressure was hammering the plugs out of the block. Belt change solved that problem.

 

That was my first experience dynoing anything. I would like to try to get mine on a chassis dyno. If and when I do, I'll have all of my changes laid out with all of the parts set aside for each change, much like they did for the wind tunnel testing, so that things can be swapped as fast as possible.

[zredbaron]

Thanks Jon! Great input, thanks for sharing how you experienced Arnie as well. Thought we had captured the pressure surge detail in this thread... good catch!

 

I still think about that mexican food we had for lunch! Holy crap that was good. Stress-relieving soul food, I say!

[steve260z]

Thank you, Steve.

 

My goals were to collect and compare A/F ratio, torque and power plots for the following on the same engine, same dyno, same day:

 

• 40DCOEs w/36mm venturis
• 45DCOEs w/36mm venturis
• 45DCOEs w/38mm venturis
• 45DCOEs w/40mm venturis

My purpose was to confirm venturi selection, and my R&D desires were hopeful the data would back up my "stalled carburetor" theories (the 40DCOE). This is not possible to confirm or deny without an A/F graph. The BSFC was an unexpected bonus to aid this research, but it's useless by itself. For my application, anyway....

 

In short, because Arnie and I miscommunicated, the internet still does not possess such a comparison to the best of my knowledge. Upset me greatly. It's entirely possible I would not have found an alternate, in which case nothing was lost. I did not have such a choice, as I had already "confirmed" his shop met my needs. It didn't.

Oh yes. I remember that was your goal. I was certainly looking forward to those numbers.

[zredbaron]

3 of 3, Part 1: The Data

 

 

The Data:

1. What I don't have, which really hampers our ability to draw emperical conclusions:
   1. A/F ratio graphs
      1. All theories on intake "stalls" / turbulence / reversion...  dataless.
      2. Horsepower and Torque only. Better than zero, but doesn't address the whole point of my R&D…. A/F data.  
      3. I’ll be able to theorize once all is said and done and I have a tuner’s feel for the 45 DCOEs, but that won’t be until this summer.
   2. Timing settings for 40 DCOEs
      1. The timing was already ball-parked from the chassis dyno in Arkansas from the last engine build.
      2. There were only a few pulls on the 40s. I do not recall if the timing was adjusted or not. I know the main jets were slightly adjusted, but not by much.
      3. Again, I withdrew interest in the details once I learned A/F wasn’t available
   3. Timing/Jet settings for 45 DCOEs w/36mm venturis
      1. I didn’t capture this either. Same reasons… hands off. Small space. Too many cooks in the kitchen. Not enough time. You get the idea.
2. What I do have, which is still useful:
   1. Power and Torque Plots
      1. Easily compares result of upgrading intake CFM capability by way of larger DCOE body and intake manifold
      2. Pics below.
   2. Jetting (I think!?)
      1. 40 DCOEs (36mm venturi)
         1. 165 mains
         2. 195 air correctors
      2. 45 DCOEs (40mm venturi)
         1. 190 mains
         2. 195 air correctors
      3. All Combinations:
         1. F11 emulsion tubes
         2. 60F8 Idles
   3. Timing
      1. Final timing only. I didn’t capture what I walked in with, because the mounting bracket for the crank sensor was different. Joe caught that it wasn’t aligned to the correct tooth, which was essentially corrected by the knobs. It was off by 12 degrees since 1999! Credit to Electromotive for their design being able to easily “fix” it unknowingly with a knob.
      2. Electromotive timing varies linearly between points in the RPM band:
         1. Init:  27 degrees
         2. 3k:   38 degrees
         3. 8k:   35 degrees
         4. Note: I did not use a voltmeter to confirm accuracy of this part. Knob settings only.
      3. Pic and graph of final timing below.
   4. Custom, Recreated Power Plots!
      1. Taking the raw data tables such as the one shown in the post above, I manually typed the different runs into Microsoft Excel.
      2.  I made the following graphs (all posted below)
         1. 40 DCOEs with 36mm Venturis
         2. 45 DCOEs with 36mm Venturis
         3. 45 DCOEs with 40mm Venturis
         4. BSFC (both raw and smooth)
         5. HP vs. fuel flow rate
         6. Torque vs. fuel flow rate
         7. They're pretty easy to ready visually, I think. Put a lot of time into them.
   5. Peace of Mind
      1. Engine is solid and ready for the next step!
      2. That’s priceless! So very glad that the engine was put on the engine dyno, despite the lack of desired data.
      3. Again, I would repeat this experience and recommend it, I simply have a few lessons learned.

Edited March 27, 2018 by zredbaron
Typo of 40 DCOE when it should read 45 DCOE

[zredbaron]

3 of 3, Part 2: Data Analysis

 

Data Analysis:

 

1. Torque and Power Plots
   1. 40 DCOE (w/36mm venturis), analysis relative to 2015 plot
      1. My gut reaction when I saw the first plots was that the shop headers + commercial muffler (and associated head loss, i.e. resistance to flow) capped torque around the 240 ft-lb range.
      2. The plateau ended early. On the “poor” dyno plot from April 2015 (with my headers), the torque plot is flat from 4500 to 6000 RPM. This dyno’s torque plot is flat from 4500 to 5500 RPM.
      3. 500rpm may not sound like much, but that’s a 33% difference in width of flat, peak-torque RPM. That’s huge! That indicates to me that the dyno exhaust is noticeably restricted.
      4. It also appears to peak approximately 300 RPM earlier than the previous run (5000, down from 5300).
      5. Additionally, the plateaued shape of the torque curve made it “obvious to my mind” and seems slightly capped in magnitude but I have insufficient data to support my intuition.
   2. 45 DCOE (w/36mm venturis), analysis relative to 40DCOEs w/36mm venturis
      1. Adds about 5 ft-lbs before plateau RPM and about 15 ft-lbs after plateau RPM
      2. Adds about 10-15 hp before plateau RPM and about 15-20 hp after plateau RPM
      3. 245 ft-lbs torque (or more) from 4400-6000 RPM… more than 3x the width of the same plateau on the same day with different carbs. Huge increase in intake capability… but only marginally increases peak magnitude in torque plot? Again, to me this indicates a restricted exhaust.
      4. Torque gain is in width, which now has peak plateau range of 1600 RPM. > 300% is huge!
      5. In my mind, the peak benefits to the WOT horsepower plot will be unveiled once we uncap the exhaust.
   3. 45 DCOE (w/40mm venturis), analysis relative to 36mm venturis
      1. This shouldn’t be the case! Something is capping CFM. See Weber chart below.... 36 and 40mm are very different performing chokes.
      2. Since this is the case, this means the carburetors are NOT the choke point any longer. Have I mentioned it might be the exhaust?
      3. Not a significant change from 36mm venturis
      4. Drastically change air delivery? No change.
      5. Jets didn’t change performance much anymore, either. Seems odd at peak RPM in a race motor, doesn’t it? Really odd. At peak power you change a variable and… not much? Sounds restricted to me.
      6. Upper limits of Fuel delivery? Doesn’t seem to run out of fuel.
      7. In my mind, the equal performance of 36mm/40mm venturis within the 45 DCOE confirms my suspicion that the engine dyno plot is torque limited due to the shop headers.
      8. Pictures comparing Mark’s “Stahl headers” with the shop’s “Stahl headers” are below.
         1. The shop told me the header differences would be negligible
         2. Judge your own gut instinct for yourself!
      9. At the end of the day, I still have a really nice shape power and torque curve!
      10. At the end of the day, the tech was impressed and was happy to tell me “your Z motor did better than ours did!” Inquiring further, “the shop L6 motor” produced 270hp on their dyno with the same header. I know no further details. For what it’s worth. Pretty much a fridge sticker.
2. Coming this Summer… on the Chassis Dyno
   1.  36mm vs. 38mm vs. 40mm venturis (45 DCOEs only)
      1. With A/F Data!
         1. Show us what is happening during peak RPMs and plateaued RPMs and other RPMs… confirmation of proper tune.
         2. Show us that chassis data A/F can be more flat with 45 DCOEs than yesteryear’s chassis data on 40 DCOEs… any conclusion with a big grain of salt, unfortunately.
      2. With different exhaust!
         1. Show us the difference in torque plots, the plateaus and the new peak RPMs
         2. Sing us an L6 lullaby
      3. How’s it drive?
         1. After writing down all of the venturi/jet combinations, practical driving will be very relevant for autocross selection.
         2. Again, the purpose of this engine is to have power / torque widely available at all pedal positions and not for WOT/high RPM numbers.
         3. With butt-dyno reports!

 

 

Fin.

Edited March 24, 2017 by zredbaron

[Andreas]

Love this thread! Great reading, keep up the good work!

[steve260z]

Awesome...Can't wait for the chassis Dyno results. Thanks for posting.

[ryant67]

Since the header difference is negligible, you should probably just sell that Stahl one you have.  I *guess* I could take it off your hands...

Thanks for sharing so much information.  I could feel your frustration of not getting the full picture, despite you setting out with that as a goal.  Still, some good info to be had, so it wasn't a waste.  

Regarding your XDi timing - is the 1000 dial so high to adjust for being 2 teeth off on the magnetic sensor?  27 advance seems terribly high!  With the two teeth retarding timing 12 degrees that would put you at 15 though, which seems sensible.  BUT then you would only be adding 11 degrees to that figure, meaning that at 3000 RPM you are at only 26 degrees advance, and just 22 ish around 7000 RPM.  That seems VERY conservative, and from what I have read on this very forum, you would potentially be leaving a fair bit of horsepower on the table.  

Might be an oversight, or perhaps I am misinterpreting.  

[tube80z]

Here's what I can add.  I haven't dynoed any of this but I used to own a flowbench and did a lot of work flowing things (heads, carbs, mufflers).  Some of those things were Weber carbs. When you get to a 40 running a 36mm choke you are maxed for the most part when it comes to flow.  Sure you can put in larger chokes but you're only changing how it responds when you're not maxed out.  Assuming the engine wants all that air then to make more power you need to move up carb sizes.

 

Here's what I saw on my bench.  Weber 40 with 4.5 aux venturi compared to Weber 45 with 4.5 aux venturi.  Below is carb and then secondary choke diameter.  What seems to control flow is a lot of the shape changes seen by the air when it goes through the carb.

 

40 -- 32 out flowed 45 -- 32

40 -- 33 out flowed 45 -- 33

40 -- 35 tied 45 -- 35

40 -- 36 lost to 45 -- 36

40 -- 40 lost to 45 -- 36

 

What you saw for power changes doesn't surprise me.  Our old engine that was smaller than your combo worked much better when running the 38mm chokes with the 45 carbs.  It gave up a little down low but could pull all the way to 7500 where the limiter was set.  When running the 40s with the 36mm chokes it started to give up a little over 6300.

 

Have you ever seen David Vizard's formulas?  If I did the math right it claims your sweet spot to be a 37.25mm choke at 7K.  So I'd say you're right in the ballpark with what you've got now.

 

Hope this helps,

Cary

[Ereschkigal]

Thanks for the data.

[zredbaron]

Minor update.

 

At the end of last week, I more or less woke up with the epiphany that I wanted to re-perform the engine dyno. The data and R&D experience was really, really important to me and I was really down about it. So I decided it was totally worth revisiting!

 

I felt liberated from my disappointment, and reminded myself that this is my project and I can spend my time or money however I choose. This was priceless to me, so I should respond as such.

 

I was excited!

 

I called all around the Pacific Northwest. Portland, Seattle, Spokane, even in Idaho. Turns out our L6s are a real pain. Shops expect one to bring their bellhousing, which is impractical and incompatible for us. Some shops refused to accommodate, some lacked confidence in their ability to accommodate. One shop was confident in their ability to fabricate a mount, but it was a full day's labor at $500. That, and zero shops left me with any confidence that my headers would work. The headers hug tightly and even curl back under the transmission area.

 

After doing my homework, I determined that this really wasn't a good option. I could force it and spend a lot of money and time only to find out nothing mounts up. This resulted in me accepting once and for all that this experience is behind me. Still liberating.

 

The dyno that inspired the most confidence for R&D was in Seattle, if anyone ever searches for such a service. http://rpmdyno.com/dyno.html.

 

Lastly, after reviewing my experience with Loyning's Engine Service, with reminders from Joe, the real value of Arnie's legacy experience is in the "art" of operating the dyno. That is, having a true instinct for the vitality of an engine. That truly is priceless, and after two failed builds, I remain very greatful knowing that my engine was broken in correctly.

 

Lessons learned, as always. If I had it to do over again... I'd still go to Arnie Loyning for his experience and the fact that he has a known mounting solution for L6s. I simply would have more realistic expectations next time! 

[zredbaron]

Since the header difference is negligible, you should probably just sell that Stahl one you have.  I *guess* I could take it off your hands...

 

Regarding your XDi timing - is the 1000 dial so high to adjust for being 2 teeth off on the magnetic sensor?  27 advance seems terribly high!

 

Hah! Fat chance. I don't agree with their assessment of "negligible," and even if I did, I am not parting with my only headers. Can't knock you for trying! LOL

 

No, the ignition settings are corrected/actual -- "two teeth off" was for my previous build, not my present build. I do not recall the detail of why Joe chose the timing settings he did, only that the engine seemed to idle better with the advance. The 3k and 8k knobs were experimentally derived from dyno plots.

 

 

40 -- 40 lost to 45 -- 36

 

What you saw for power changes doesn't surprise me.  Our old engine that was smaller than your combo worked much better when running the 38mm chokes with the 45 carbs. 

 

Have you ever seen David Vizard's formulas?  If I did the math right it claims your sweet spot to be a 37.25mm choke at 7K.  So I'd say you're right in the ballpark with what you've got now.

 

Thanks Cary! Question.... you had a 40mm venturi in a 40DCOE body? How? (no venturi?)  Vizard's formula's ring a bell, but it's been awhile. I do know that from all of my previous homework on paper, I believe the 38mm is the likely choice. Looking forward to the chassis dyno results.

 

I also suspect that there's a decent chance I might choke it down to the 36mm for autocross driveability. Too many variables to predict, at present.

 

 

Thanks for the data.

 

You're welcome!

[tube80z]

Thanks Cary! Question.... you had a 40mm venturi in a 40DCOE body? How? (no venturi?)  Vizard's formula's ring a bell, but it's been awhile. I do know that from all of my previous homework on paper, I believe the 38mm is the likely choice. Looking forward to the chassis dyno results.

 

I also suspect that there's a decent chance I might choke it down to the 36mm for autocross driveability. Too many variables to predict, at present.

 

For the 40 carbs it was straight through with no venturis.  It was a no cost test and more of a curiosity for me.  You have one of Vizard's graphs a few pages back in your post.  So my guess is that you either did see it or some other pub that referenced it. 

 

In case you're curious here it is.  

 

choke(mm)=(CV x rpm / 2600)^0.5

 

CV us cylinder volume in CCs and RPM is the point of max power.

[Chickenman]

Zredbaron.Have you thought about heading North? Specialty Engineering in Delta Bc is one of the top L-serie's race shops on the West Coast. Andy Pearson is the owner and is an incredible fabricator and engine builder. His cars and engines have won numerous SCCA National Championships and Runoffs  and Nasport events. His dyno is constantly running L-series and he has specialised in Datsun engines and Chassis since the early 80's. One of his  street 2.3 stroker L20b's recorded 178 rwhp on a Dynapak hub dyno at Brown Bros Ford. 

 

http://www.the510realm.com/viewtopic.php?f=3&t=26048&hilit=Dyno&start=270#p248210

 

 

 

Knowing Andy personally, the programs you wanted to run are his standard testing procedures. If any one can run accurate testing done the way YOU want.. it's Andy at Specialty Engineering. Would certainly be worth a call. Mention that " Chickenman " recommended you to them. 

 

http://www.specialtyengineering.ca/

Edited March 27, 2017 by Chickenman

[Chickenman]

And in case you want a really different Power plant. Andy bought a bunch of Infinity IRL engines when  Nissan abandoned Indy Racing.

 

[zredbaron]

Nice shop, Chickenman! Very cool. Just barely past the Canadian border, too.

 

The shop isn't able to accept any new cars/projects until late summer (I didn't inquire about engine dyno services -- no longer interested, I'm proud to say). So that's out. Too bad, as I would have been happy to commission some of my other projects. Going to look into roll cage fabricators this week... hoping to find a shop that can do both my exhaust and strut braces.

 

Fascinating powerplant! They have a 3.5L and 4.0L version that make about 650-700 bhp @ 11k! Radical. Would need an updated ECU solution and a transmission.

 

Thanks for sharing!

Edited March 29, 2017 by zredbaron

[JMortensen]

There has to be a place closer to you, but if you can't find one Chase Race is right around the corner from me. You could leave your car here if necessary for some reason. Does exhaust, cages, all that stuff. Doug bent the main hoop for my cage based off of Dan McGraths jpg image posted here. Fit perfectly.

http://www.chaserace.com/rollbars.php

[zredbaron]

Still making progress. I haven't finalized a fabrication shop... but the rear suspension and drivetrain mods are complete and I'm happy to announce that my heart has officially mated with my body.

 

Details.... so painful along the way, but so worth it forever after.

 

 

 

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