Engine Dyno time - Data, data, and more data

[jgkurz]

Hi Folks,

There have been several comments here lately regarding dynoing engines so I thought I'd start a thread for my project. I will be on the dyno in Feb sorting out my new stroker 427. The dyno is a Superflow but I don't know the exact model yet. The dyno is run by the same folks who have done most of my build so a big plus. They have very nice FE dyno headers with pyrometer probes in each tube which is helpful. The ignition on the dyno is an MSD 7ALx so decent.

My plan was to dyno with the nice headers and ignition then incrementally change to the components that will be in my car. I will be running FPA TriY headers, MSD 6AL2-P, and a 2" oval 2x4 aircleaner. I'm a data guy and really enjoy the information I can gather from a properly planned dyno session. I kind of look at it like a science experiment..

Some folks might wonder why I don't just start with the components I will be using on the car. For kicks, I want to see what the engine is capable of before I hinder performance. My carbs will be fairly easy to adjust which makes the process less time consuming. The dyno owner/operator is a friend so I will be able to do a lot of the menial tasks myself which is ideal. 

I'm very curious how my FPA headers will do compared to the larger dyno headers. Stan at FPA said the highest HP he's seen with my headers was just under 600. I am planning/hoping/expecting more.

The ignition is another factor. I really like my MSD 6AL2-P but the 7ALx series should allow more power. I'm not sure if it's 5hp more or 20hp more. We'll see.

I WELCOME ANY SUGGESTIONS, COMMENTS, OR RECOMMENDATIONS.

-John

[cjshaker]

I would be surprised if you saw any improvement going from the 6AL to the 7AL. Both are very good systems. But I think it's a great idea running it for full potential before adding the air cleaner and your headers. Especially the air cleaner. That way, if you wanted to run it at the track without an air cleaner, you would have a very good idea of how to jet the engine to compensate for the increased airflow. That's what I plan on doing with my next build. It would take a lot of the guesswork out.

The only suggestion I would have is.....GIVE US DETAILS

[jgkurz]

I would be surprised if you saw any improvement going from the 6AL to the 7AL. Both are very good systems. But I think it's a great idea running it for full potential before adding the air cleaner and your headers. Especially the air cleaner. That way, if you wanted to run it at the track without an air cleaner, you would have a very good idea of how to jet the engine to compensate for the increased airflow. That's what I plan on doing with my next build. It would take a lot of the guesswork out.

The only suggestion I would have is.....GIVE US DETAILS

Doug, Interesting that you are the first to respond. I have followed your build closer than others since I also have a 69 Q-Code Mach1 soon with a 427FE.    Thanks for paving a path.. I have been tight lipped about details because I want to get results in hand rather than bench racing. Here are the high-level details of the build: 488ci 1967 side oiler with Crower crank and rods, roller hydraulic cam with Ford 2x4 MR intake and QF carbs.

Like with your setup, I will run the oval 2x4 air cleaner. While on the dyno I plan to try carb spacers to see they respond on the 2x4 intake. Barry_R posted something recently that indicated that spacers may help even out mixture in the cylinders. They also would help with heatsoak. At a minimum I want to use Nitrile carb gaskets to insulate the heat a bit.

I suspect I won't have the room under my hood but maybe... You would know more about this than I would. 

[thatdarncat]

Thanks in advance for sharing what you find, always interesting to read. I'm with Doug, I don't think you'll see any difference between the MSD 6AL and the 7AL, everything else being equal. The ignitions job is to get the spark lit, once it does that its pretty much out of the picture. Where you might see a difference are in the programmable MSD boxes that allow you to tailor the timing curve per cylinder & rpm. I think you'll find the Ford oval air filter costs power. When I first started racing my '68 Torino years ago with 427 & tunnelwedge 2-4v's I found I gained 3-4 tenths when I removed the oval air cleaner and 2" Ford paper filter. It was so bad my friends called it the Cobra air choke! I just put the 2-4v's and C7ZX med riser intake back on my Shelby this past summer before I went on Dragweek. I'm using the 3" tall K&N filter to gain the extra inch. My motor hasn't been dyno'd and I didn't have a chance to test and get everything dialed-in like I would have liked, but I found between half to a full tenth in the quarter each day I removed the air filter at the track.

[jgkurz]

Thanks in advance for sharing what you find, always interesting to read. I'm with Doug, I don't think you'll see any difference between the MSD 6AL and the 7AL, everything else being equal. The ignitions job is to get the spark lit, once it does that its pretty much out of the picture. Where you might see a difference are in the programmable MSD boxes that allow you to tailor the timing curve per cylinder & rpm. I think you'll find the Ford oval air filter costs power. When I first started racing my '68 Torino years ago with 427 & tunnelwedge 2-4v's I found I gained 3-4 tenths when I removed the oval air cleaner and 2" Ford paper filter. It was so bad my friends called it the Cobra air choke! I just put the 2-4v's and C7ZX med riser intake back on my Shelby this past summer before I went on Dragweek. I'm using the 3" tall K&N filter to gain the extra inch. My motor hasn't been dyno'd and I didn't have a chance to test and get everything dialed-in like I would have liked, but I found between half to a full tenth in the quarter each day I removed the air filter at the track.

Great info Kevin. I agree that the Cobra 2x4 air cleaner is going to significantly affect power. I have a K&N but that will only be a minor improvement if any over a paper element. I don't know of a better option given my hood clearance. I will run the air cleaner on the street but not on the strip. On the street I only have 255/60-15 BFG's in the rear with 4.11's so even with the power loss I won't be able to put much to the pavement. When racing with drag radials I will only use the base of the air cleaner with some kind of foam seal against the hood. The carbs are annular discharge with no air horns so they should work well if I jet up. I'm hoping a simple air bleed change will work vs a full jet change. Dyno time should help me figure this out.

[Nightmist66]

Another option for heat isolation is wooden carb spacers. I run a 1/2 thick Jegs brand on mine. It appears to be a repackaged Edelbrock, but not certain. Excellent quality. Can't wait to hear the results, and maybe a pic or two?   

[CaptCobrajet]

A 7-series box is about 10 hp better than a 6-series box.  As rpm and compression go up, it could be more.  I tested the 6 vs 7 back-to-back to 6500 rpm @ 10.5:1 c/r. when I dabbled with the Engine Masters a few years ago.  Plug gap, coil, and ignition wires can affect power notably, as well.

[jgkurz]

Another option for heat isolation is wooden carb spacers. I run a 1/2 thick Jegs brand on mine. It appears to be a repackaged Edelbrock, but not certain. Excellent quality. Can't wait to hear the results, and maybe a pic or two?   

Jared, Do you run an open spacer or a four hole type like this? I'm curious if the four hole is any better or worse than the open type given the 2x4 intake already has a four hole top.

[Nightmist66]

This is the one I have.



Just checked on Jegs' website and didn't see the 1/2" wood listed under their name anymore, just a 1" open spacer for 4150 and a 1/2" open for 4500 flange. The manifold I have is an old Ed F427 dual plane with plenum divider and a notch at the rear for a 3 barrel. I have not compared a 4 hole to the open, so I can't say which is better on mine and I'm not sure about yours either. Maybe someone with more experience knows or just try both side by side to find out?

[CaptCobrajet]

Summit sells the 4-hole wood/phenolic in their house brand for $30 each with gaskets and studs included.  The MR dual plane will need the 4-hole design.  It won't play nice with anything else the way the manifold is made with a 4-hole plenum.

[Barry_R]

I have a 6 box on my dyno, and an old school 7 box in my car, and a digital 7 mounted to my EMC plate.  I have seen the 7 boxes show an improvement in higher RPM & higher power/compression builds, but have not seen anything on milder builds at the 400-500 HP ranges.  Probably gets more important as the potential for marginal ignition occurs.

I definitely see something in plug gap - and if you get it too big it'll snuff the center button in an MSD cap.  Big gaps might also contribute to that box variable as voltage demand goes up.  Have not found anything in plug wires, but I might be starting on the high quality side of things - only rarely use cheapies and those are for engines where guys desire the repro wires for cosmetic reasons.

I have to disagree on the spacer deal.  I have tried eight million spacers by now, and have decided that the only real trend is that some engines like certain spacers - and some don't.  Every time I try to predict the result it does something else, and they are pretty easy to bolt on and try them.  Seems I am always out of spacers 'cuz one or another leaves the dyno installed on an engine.

I really need to get eight O2 sensors installed so I can monitor cylinder to cylinder variables better.  The averages in the collectors, EGTs and plug readings give us a "window" but I think things change through the RPM band and that might be masking the real data.  Scott (from EMC) has been running individual cylinder feedback correction on their's and I think they are really finding distribution things that can be beckfed into our more normal projects in some fashion.

[jayb]

I did a back to back MSD Digital 6 vs. MSD Digital 7 on my 650 HP dyno mule when I was doing the testing for my book.  Zero difference between the two.  This was an 11:1 compression engine with a roller cam, run to 7000 RPM, made 675 HP peak with the Victor intake.  I can see where with a higher HP engine, with more compression and/or running at higher RPM, the MSD 7 would make more power, but on engines like my dyno mule, my testing showed no difference.  It would have been interesting to try that test on my supercharged FE when I had it on the dyno; I only ran that one with the MSD 7, but I'll bet that the MSD 6 would have been down on power in that case.

On the carb spacers, you've got to try them on the dyno because not all engines will behave the same.  For the most part, what I found was that the four hole spacers tended to improve the low and mid range performance, and the open spacers improved the top end performance at the expense of the low and mid range.  But there are lots of examples I've seen where this general rule doesn't hold true.  One thing the dyno is good for is figuring out what your engine wants in terms of spacers.

[CaptCobrajet]

On the spacers, I was specifically talking about the MR 2x4 manifold.  It has four holes, and basically almost an individual runner situation.  Anything other than a four hole spacer is going to hit a wall on top of the manifold.  I have stuck an open spacer on there just to try it, on both the MR and HR 2x4 intakes, and they like the 4-holes every time.  Open plenums and open dual planes are trial and error, like you guys said. 

I have never used a digital 6 box.  I tested a 6AL vs a 7AL when I saw a difference.  Also did it in a car, where it was .04 on a 1/4 mile pass.....same day, same track, weather considered.  Hard to beat a good ole antique 7AL-2 in my book, but I don't think they will live as long on the street as a 6-box.  I have not come over to the dark side of the digital boxes yet, lol.

[cjshaker]

John, if you're putting this in a '69 Mustang, it won't matter on spacers....cause you won't be able to fit one on the intake under the stock hood, unless of course you have some sort of scoop. There's only about 1/4" clearance over the 2" oval air cleaner using JUST regular carb gaskets.  Maybe 1/2" at the most.

Surprisingly, with my Mustangs tight engine compartment, lack of any way for heat to escape, and headers, I have not had any problems with underhood heat or carb heat soak. I have a good radiator and keep my engine temps down to no more than 190 though. But I think the fact that I run 50% 110LL gas may help in that department.

I didn't see you say anywhere what style of heads you were going to run? Just curious because if it's factory MR heads, it's gonna be real tight with the header bolts and shock tower bracing! If it's any of the aftermarket aluminum heads then you should be good to go. Good luck with your engine and let me know if you have any specific questions.

[jgkurz]

John, if you're putting this in a '69 Mustang, it won't matter on spacers....cause you won't be able to fit one on the intake under the stock hood, unless of course you have some sort of scoop. There's only about 1/4" clearance over the 2" oval air cleaner using JUST regular carb gaskets.  Maybe 1/2" at the most.

Surprisingly, with my Mustangs tight engine compartment, lack of any way for heat to escape, and headers, I have not had any problems with underhood heat or carb heat soak. I have a good radiator and keep my engine temps down to no more than 190 though. But I think the fact that I run 50% 110LL gas may help in that department.

I didn't see you say anywhere what style of heads you were going to run? Just curious because if it's factory MR heads, it's gonna be real tight with the header bolts and shock tower bracing! If it's any of the aftermarket aluminum heads then you should be good to go. Good luck with your engine and let me know if you have any specific questions.

Thanks Doug, You confirmed what I suspected. I will post details soon.