experimental engine dyno project

[MetroMPG]

Oh, and this may not work since you've already bumped up compression a bit, but...

--> quantify the effect of manually advancing ignition timing (past factory settings) at cruise, potentially on both regular and high octane/premium gas. Since I assume this engine doesn't have electronically controlled ignition.

[JRMichler]

I did not clearly write what I was trying to say. If most of your driving is at a particular RPM, then efficiency at that RPM is of interest. Efficiency at 5000 RPM is not of interest to an ecomodder.

For example, testing heated intake air need only be done normal highway RPM and below. Testing at a particular RPM is done over the complete range of manifold absolute pressures. At each MAP, measure the torque and fuel flow. Do this for a range of RPMs, starting at idle and ending at normal highway RPM. Repeat the entire series of tests for different intake air temperatures.

Plot the results as an engine performance graph, with temperature on the horizontal axis and torque on the vertical axis. One graph for each RPM. Each individual test at a particular RPM will add a specific fuel consumption value to the graph for that RPM. The finished graph will show the relationship between peak torque and intake temperature. It will also show the best intake air temperature for any torque at that RPM.

The same data can also be plotted with RPM on the horizontal axis, torque on the vertical axis, and specific fuel consumption as the data. One plot for each intake air temperature. This a conventional engine performance map.

[Xist]

Originally Posted by fujioko

so I built an engine dyno.

Why haven't any of us built a dyno? The most difficult part is deciding whether to follow "Building a Dyno for Dummies" or "The Idiot's Guide to Building a Dyno."

I could not imagine building one of these. Will we eventually have someone build their own wind tunnel?

Pgfpro, tell him how to convert to lean burn! Ah, dang, the Hydro Kid could do it, but where is he?

[Cobb]

You use your coolant to preheat the incoming air? What temp do you run your water at? 180, 190, 200 F? I find my 2010 insight starts to retard timing and looses torque as the water gets above 186 to 200. When it hovers around 180 its fine.

Originally Posted by fujioko

[gone-ot]

Add an after-market *KNOCK-detector* sensor and monitor to know WHEN/IF the engine combustion is slipping into pre-detonation *knock* due to too much advance.

[oil pan 4]

Originally Posted by fujioko

]]The intake air temp is another experiment that will get done this winter. The B3 Miata really loves cold air and I did some experiments by bypassing the throttle body heat and found a bunch of power. On the other side of the heat scale I plumbed in a liquid to air heat exchanger. The Miata engine snorkeled +170F air 100% of the time. The car ran like crap and and lost a bunch of power. I'm sure there is a happy medium or some tricks that can be done.


The B3 Miata snorkeling uber hot air through a heat exchanger. I got the idea from another forum and gave it a try. This is definitely a dyno experiment in the near future

Thanks for the comments and feel free to keep adding to the idea list.

Jim

A few of our members used a heater core in the air box as their intake air heater. That is a low dollar alternative to using an after cooler.
I say do a manually controlled experiment on your dyno, find the sweet spot and use automation to maintain your sweet spot set point and then install a Normally open valve to shut off hot coolant flow for when you need power.

[Chrysler kid]

Why a miata? With such small occupancy and it's appeal mainly for scca events.

I'm sure the festiva guys are thrilled

[Xist]

Hey, I was going through the Amazon sales, and this will be discounted tomorrow morning: Amazon.com : Pirit PWL-03-25 25-Feet Heated Hose : Plumbing Hoses : Patio, Lawn & Garden

[2000mc]

How about tracking oil temperature. Then if higher temps appear helpful, and if you think it would be safe to go higher, some sort of heater.

Capacitive discharge ignition, and then with wider plug gap

[fujioko]

Great! more things to add to the list!

In reply to MetroMPG,

Valve springs... well it's a good idea, but that one is going to take some research. The electric water pump and bumping the ignition timing can be done. The ignition curve is fully programmable and is one of the basic things I need to develop. The current ignition curve is a hodgepodge set of data points and is not optimized.

in reply to 2000MC,

Oil temp and oil brand will get added to the list. Something to conceder is this dyno engine was kept "loose" by not replacing the piston rings and bearings when it was disassembled and cleaned. I suspect most of the premium synthetic oils will work but may also be consumed. I won't be able to track the consumption in a short term tests.

The ignition system is something I also want to develop further. The dyno is equipped with a stock Festive distributor, however the Miata has a custom coil pack ignition. For base line testing I'm going to use the stock Festiva distributor but eventually I'll swap in the coilpack system from the Miata. Once the coil pack is evaluated, I'll take a look at other systems.

in reply to Chrysler kid,

Using a Mazda Miata as a test vehicle is based on my own flawed logic, but it's the type of car I prefer. Front engine rear wheel drive, real suspension and excellent brakes. I'm a car guy and I don't really like FWD econoboxes. While there are better cars and better engines the Miata is the car for me.

In reply to old tele man,

I wasn't aware of aftermarket knock sensors until I just googled them.... Cool! I have to do some more research but that looks like a winner!

In reply to Cobb,

The intake air temp ranged from 140F at idle and maxed out at 170F in cruise. At the time I was running a Megasquirt II and I had disable ignition retard based on air temp. The trouble I encountered was the engine ran really lean and pinged under moderate load. I remapped the volumetric efficiency tables to accommodate the higher air temp and the fuel consumption went up and the car still ran poorly. I didn't spend a lot of time experimenting because this mod borderlined total engine destruction and I figured it would get sorted out on the dyno. Eventually some sort of active control will get developed to allow cold air on acceleration and warm air in cruise.

In reply to JRMichler,

Point taken, the experiments will be conducted for maximum value in regards to published data. I'm sure I'll screw up something and folks with an eye for detail will hopefully chime in and point out my mistakes. I'm open to re-running tests until I get it right.


Something for everyone to consider, This dyno is currently set up for Megasquirt so the results will vary. When time allows, I'll add the factory Festiva ECU for comparison and may need to revisit some tests. This is a very ambitious project for a hobbyist but I think we can get some cool data.

Ultimately my goal is to squeeze 50 MPG out of my project car in real world driving. In the right hands the Miata is certainly capable of the magic 50 MPG but I want to try to do it without a handful of driving tricks.

Thanks for the comments and ideas!

Jim