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Fuel Injection
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With all the gas mileage concerns, I am wondering how many of you have installed some sort of fuel injection on the 454. I talked to my son and he, as a former hi tech mechanic believes that gas mileage could be increased by as much as 10 to 20% over a carburated engine. Most of this comes from optomizing the air fuel ratios, especially during acceleration.

Posts: 35 | Location: Lanesboro MN | Member Since: 09-01-2006Reply With QuoteReport This Post
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I considered it, especially having TBI on a pickup 454. At the time I stuck in the 502, TBI was not recommended for the HT502 crate motor. Later, their was a set up available, but, on the advice of my cardiologist, I pay no attention to fuel consumption.

My carb is dialed in on a flow bench, so it is pretty good, mixture wise. I have hooked a DVM to an O2 sensor I installed, and it is pretty close to stoichiometric. Close enough that I have only corrected it a little. I am, however, considering installing a detonation sensor that will alert me to the need to retard the spark, depending on fuel quality, temp, load and grade. My ears are no longer able to her the tink of detonation, and the hearing aids are no fun in a MH. The engine seems more responsive to timing than mixture. My expensive dyno time on other engines showed pretty much the same. I wish I could afford some dyno time with this one. Frowner

I also looked into aftermarket FI, but did not own a laptop, then. The combined price of a laptop and the system was not inconsequential, and would have taken quite a while to pay me back in mileage. Of course, fuel costs more now.

I also looked at CA smog laws. That did it. I would have had to change the trans, too, with the right computer. With the torque of a 502, the computerized 4L80E is close to the edge of its durability envelope. I know how much the TH 400 can take. Lots. Plus, my 502 is already emissions non-compliant, requiring all manner of jiggery-pokery to pass smog.

FWIW, one of my other toys is a Jag with an LTI vette engine and drive train. Smog is fun with that, too. Anyway, in browsing through a performance catalog, I see quite a few manifolds offered to retrofit a carb to an LT1, but no one seems interested in putting the LT1/LT4 FI on a carb or even TBI or TPI small blocks. Whyzzat? Do you suppose they know something?

My friends with TBI MHs don't get much better mileage than I do, but they climb better at higher altitudes in the Sierra. Anyone been up to Rock Creek Lake in a MH lately? I recall some airplane carbs had a little aneroid altitude compensator that leaned out the mixture at higher altitude. My friends with later engines with more sophisticated FI also have longer and heavier MHs, so a mileage comparison is not too useful.

My take on mileage is that I do not like long drives, anyway, so our destinations are close. We are fortunate in where we live. I look at the whole entity of motor home expenses as my travel and entertainment budget combined. I know others who spend much more on many things than I do, so it evens out. I bicycle almost daily, so there are no short car errand trips, and most of my vehicle travel is by motorcycle, again, quite fuel-efficient. Even when I worked, I commuted by bicycle, motorcycle, or Shanks Mare, making my monthly fuel bill very low. Our Barth does not even have a power cord, so our camping expenses are quite low. I fly for free, but a week in the Camargue is still way way more expensive than a Barth trip. Even staying in town is not cheap. Ticket prices to concerts, festivals and events can really run up the entertainment budget. We are going to hear the Dublin4 tonight in an Irish bar, and will probably run up a pretty decent tab. You have to compare your MH expenses to other fun and games, entertainment, hobbies, etc. It would be unrealistic to compare MH expenses to staying in the house watching TV.

Oh Oh-thread drift. Drifting into personal finance and emotional well-being.

But, after all that, I am still open to a TBI or other FI conversion.

I think your son is in the ballpark on the FI potential for mileage improvement. Perhaps more so on cruise than climb. However, FI 454s have lockup converters, so that also improves mileage, and that advantage that would not be available with just a change to FI. We had a taste test, and have a new brand of kim chee and really, really like it. Now the dog's breath is really something. I guess it would be interesting to take a yearly fuel bill and reduce it by 10-20% and compare that to the cost of a changeover.


84 30T PeeThirty-Something, 502 powered
Posts: 7397 | Location: AZ Central Highlands | Member Since: 01-09-2001Reply With QuoteReport This Post
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Hey Bill, I agree on the Kimchee! Just found some really great stuff. Being from Hawaii I love the stuff. Yeah stinky breath though!
On the fuel injection; as a new buyer I would install it and just consider it part of the purchase price The payback is when you sell it and you benefit from better gas mileage and no carb problems. I personally hate Quadrajets and Holly's. Edelbrock makes a great carb and you can get parts to modify it if necessary.! Plus Cammy E. sometimes answers the phone!!! ( yeah, right!) Maybe to Jesse James.

Posts: 35 | Location: Lanesboro MN | Member Since: 09-01-2006Reply With QuoteReport This Post
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