MPGs run, Aspire SE

[mikeyjd]

http://www.oreillyauto.com/site/c/se...lug+non-fouler

No worries, adjusting fuel pressure is far more extreme, this just helps keep the check engine light off and the computer working properly with a slightly leaner mixture.

The inside of the fowler will need to be drilled out for the o2 to fit. This exposes the tip to heavier gasses with less o2 .

Edit, note the part shown is for Berts old truck, 18mm
There are lots of smaller sizes. 18mm works.

Drilled out to 1/2 inch?

[Zanzer]

If you swap to a different flow injector be sure to do some calculations first. Swapping to a lower flow rate can cause the smaller injector to operate at a higher duty cycle and pulse width. Basically just over-driving the injector and causing it to fail sooner. You typically want to stay under 80% duty cycle.


Tom, I think one thing that may be hurting you is the Aspire's batch fire. Have you thought about running a Megasquirt so you can convert to sequential?

[TominMO]

Good points, zoomx2 and Zanzer. Maybe I will not mess with the flow rates after all.

[Zanzer]

You can play around with them no problem, just calculate what the injector is capable of first. Bosch made tons of injectors with almost any flow rate you can think of and there are tables of them all over the net. There are also all kinds of injector calculators out there so just run the numbers and see what it recommends and then find the injector you want (allowing for duty cycle) and the correct impedance

If you find one you like but it doesn't have the correct spacers or cap style, just let me know and I can usually retrofit it with the spacer(s) and pintle caps you need.

[TominMO]

You can play around with them no problem, just calculate what the injector is capable of first. Bosch made tons of injectors with almost any flow rate you can think of and there are tables of them all over the net. There are also all kinds of injector calculators out there so just run the numbers and see what it recommends and then find the injector you want (allowing for duty cycle) and the correct impedance

If you find one you like but it doesn't have the correct spacers or cap style, just let me know and I can usually retrofit it with the spacer(s) and pintle caps you need.

I hear what you're saying and appreciate the offer, but I just spent $84 on cleaning these, and don't want to toss any more money at this part of the equation. Only option I would like is if I can adjust the flow for these injectors in a way that doesn't hurt them or the motor, and also improves mileage.

At this point, I'm thinking that the only thing worth doing, bang-for-buck wise, is the cam. But that remains to be seen. The header might be useful too, esp. when using the A/C, since the header will add HP that the A/C robs. But numbers will tell the story in the end.

@ Movin, I don't know if the anti-fouler would work with the header, since the O2 hole is in a different location (i.e. maybe different flow characteristics).

[Zanzer]

^^ No worries Tom, I can totally understand where you're coming from.

If you want to investigate it later and find some that need the changeover, just let me know and I'll do it for parts cost (usually around $15) and shipping. I really like what you're doing with this thread and I'm willing to help out if needed.

[TominMO]

Thanks Zanz.

So, some calculations.
Front spoiler/airdam cost: about $20. MPG improvement: about 7. Percent improvement: 16%. Gasoline cost per gallon: $4.00. 16% of $4.00 = 64 cents. Number of gallons of gas to break even on spoiler cost = 31.25 ($20.00 divided by 64 cents). At an average of 40 MPG, it would take 1,250 miles to break even. After that, it's all savings.

I'll eventually do the same calculations for the MPG cam, but here is a tentative number, assuming a 7 MPG increase also: $180.00 divided by 64 cents = 281.25 gallons. At an average 0f 40 MPG, that would be 11,250 miles, or maybe an average year's driving. All free money after that.

So if you did the airdam and cam at the same time, you should see a huge improvement. Bear in mind that these tests are done on an Aspire. You should go from 44 to 58 MPG @ 60 MPH. That's what I am hoping for, at least, when I install the cam. The header might help a bit too, by cleaning up the infamous Aspire exhaust flow.

With my B6 Festy, the airdam gave an improvement of only 7%. So you would break even at about 2700 miles in a Festy. But I'm testing on a B6, so maybe there's a little bit of apples-and-oranges here.

@ zoom, I looked at a good wideband and saw it was $200. My main intent is to find the cheapest way to get the best mileage, which at the moment appears to be airdam + cam for ~$200 total. I think anything you do to the injectors might yield a small improvement, and not be very cost-effective--e.g. injector cleaning, $84 + wideband, $200 = $284 for maybe a few more MPGs? Probably the same for the header, but at a cost of $340. But I am still buying the header, to both free up HP and possibly get a small MPG benefit.

[zoom zoom]

I doubt the wideband will help mpgs at all, but you'll know that the engine is running right by knowing the air fuel mixture, so you can see what is actually going on inside the chambers when you mess with the fuel system.

[TominMO]

I doubt the wideband will help mpgs at all, but you'll know that the engine is running right by knowing the air fuel mixture, so you can see what is actually going on inside the chambers when you mess with the fuel system.

Right, I understand that the wideband is just a monitor. Just doesn't seem worth buying for an MPG application. I'll just leave the fool system alone, and read the plugs. Once I install the cam, then I can play with timing to find the optimal point for fuel efficiency.

[rmoltis]

The lowest price for a wideband with gauge is $155

http://www.ebay.com/itm/271218293777?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

It may be useful down the line.

[mikeyjd]

What was the predicted hp increase on the header?

edit: I found it in matt's header thread

To be honest, I tested that over 3 years ago & didn't keep the file. As I recall header was worth around 8 HP on a stock Festiva & around 14.5 HP with head work. I will be doing some testing on some parts that I am developing at the present & bought a stock '91 Festiva to test with. So I will be able to start from scratch with base line numbers all the way to highly modified.

[rmoltis]

That 8hp is a stock exhaust as well?
Or with exhaust work?

He said over the phone minimum of 2" exhaust after the collector
To a max of 2.5.

Otherwise it would partially negate the "tuned"-ness of the header.
Leaving partial backpressure in the equation.
Removing partial hp gains.

[TominMO]

If the cam increases MPG by 7 or so without loss of power, and the header adds 8 HP (hopefully without loss of MPGs!), I will be happy. I'd even be willing to take a hit of an MPG or two for the extra HP. We'll see.

[TominMO]

Just got a PM today from Matt that my parts will be completed shortly; i.e., Aspire roller MPG cam, header and fuel pressure gauge. So when the parts box shows up on my doorstep, I will get them installed. The header will be installed later, so I can run a test on the cam alone.

[rmoltis]

You gonna keep your stock exhaust with the header?

And are you gonna get new o2 sensors while your at it?

Sounds like fun.