Author Topic: Gas Mileage: 454  (Read 106269 times)

Offline BrandonMc

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Re: Gas Mileage: 454
« Reply #150 on: August 09, 2018, 10:36 AM »
I have to say I've enjoyed reading this thread, and can't wait to reveal my MPG when the fuel system is back together.


Something not many of you have mentioned is what Octane rating are you all running? In Colorado, we have 85-87-89 available at most pumps. Now check this out, the label of a lot of P30 Chevys strictly say, FUEL REQUIREMENTS - USE 89 OCTANE OR HIGHER" This from the P30 Chassis manual page 7-92. My 89 454, and many others I'd assume says to run 89 octane!


What say you? I've always put 85 in to save a few bucks but this could be relatively important right? I suppose it depends on your locale. 



Offline tmsnyder

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Re: Gas Mileage: 454
« Reply #151 on: August 09, 2018, 11:32 AM »
The cheapest stuff available!  Yes I ran a bunch of 85 octane last summer on our 8000 mile loop out west and back.

Offline 87Itasca

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Re: Gas Mileage: 454
« Reply #152 on: August 09, 2018, 12:47 PM »
You mean 87 Octane?


There's no way I would run E85 in one of these. I couldn't imagine it would run at all well, and if it somehow did, you would ruin the fuel system in short order. These were not designed for ethanol fuels. 10% ethanol is pushing it already, any more and you're just asking for trouble.

Offline tmsnyder

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Re: Gas Mileage: 454
« Reply #153 on: August 09, 2018, 01:37 PM »
Oh yeah, 85 octane all day long.  Cheapest stuff they had.  Makes no difference in MPG, only problem would be preignition and I never heard any of that.  These are low compression engines, it doesn't need high octane. 


I do worry about the ethanol attacking fuel system components, so when I get home I arrive as empty as possible and fill up with ethanol-free, drive it around a bit, run the generator, and park it. 


Ethanol actually _increases_ the octane of gasoline, it's 113 octane on its own.   So if they are selling 85 octane with 10% ethanol, it would actually be lower without the ethanol, about 83 octane.

Offline BrandonMc

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Re: Gas Mileage: 454
« Reply #154 on: August 13, 2018, 09:55 AM »

You mean 87 Octane?


There's no way I would run E85 in one of these. I couldn't imagine it would run at all well, and if it somehow did, you would ruin the fuel system in short order. These were not designed for ethanol fuels. 10% ethanol is pushing it already, any more and you're just asking for trouble.


Definitely like to avoid ethanol based fuels. What you're saying is Ethanol is being used to affect the octane rating of gasoline?  oh wait, I see. No, definitely not running E85 AT ALL!



Oh yeah, 85 octane all day long.  Cheapest stuff they had.  Makes no difference in MPG, only problem would be preignition and I never heard any of that.  These are low compression engines, it doesn't need high octane. 


That's what I thought!  Hm?  Why do you think the label specifically says run 89 or higher?

Offline fasteddie313

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Re: Gas Mileage: 454
« Reply #155 on: August 14, 2018, 01:20 PM »
I'm no 454 expert, but..


You should get better gas mileage and more power with the lower octane gas..


In gasoline the octane is artificially increased with additives..
The additives serve to slow down the burn of the fuel and increase it's resistance to ignition..
Higher octane gas is harder to ignite and burns slower.. This is needed for high compression engines and forced induction engines.


Ethanol burns even slower, has a much lower energy density, and is much more resistant to ignition..


Ethanol burns so much slower that flex fuel applications run a lot more ignition advance with high ethanol content to get peak cylinder pressure back near TDC.. You have to fire the sparkplug earlier to get it burning right before the piston gets to the top vs straight gasoline..


Ethanol contains much less energy..
""
A.  76,000  = BTU of energy in a gallon of ethanol[/size]B.  116,090 = BTU of energy in a gallon of gasoline
""
""
[/size]Ethanol[/size]
[/size] and fuels like E85. 1.5 gallons of [/color][/size]ethanol[/color][/size] has the same [/color][/size]energy[/color][/size] content as 1.0 gallon of [/color][/size]gasoline[/color][/size]. A flex-fuel vehicle will experience about 76% of the fuel mileage MPG when using E85 (85% [/color][/size]ethanol[/color][/size]) products as compared to 100%[/color][/size]gasoline[/color][/size].[/color][/size]""[/color]
So all else equal you will get worse MPG on ethanol than gas because of the energy content difference..


Ethanol requires a different Air Fuel Ratio for a proper burn compared to gasoline..



As you can see gasoline has a stoichiometric ratio of 14.7 parts air to 1 part gasoline while ethanol's stoichiometric ratio is 9.8 parts air to 1 part E85..


So you need more ethanol for the same amount of air to get a proper fire than you do with gasoline..


Flex fuel engines have a computer that sees the ethanol content of the fuel, via a flex fuel sensor, and sees the AFR of the burnt exhaust, via O2 sensors, so the computer can add more fuel at the same amount of airflow to get back to stoichiometric with changing fuels..


Carburetors don't do that, they are tuned for a specific fuel type..
If you run ethanol in a carb tuned for gasoline then you will be mixing the same amount of fuel when you should be adding more and you will be lean..


You can tune a carb for ethanol though, but then it will be pig rich on gasoline.


Back to octane, octane is the measure of resistance to ignition.. It's easier to catch low octane fuel on fire basically.. E85 having an octane rating somewhere around 100-110 octane, so it is harder to catch on fire..


High performance engines at times need high octane fuel to keep it from catching on fire before the sparkplug catches it on fire on purpose..
Sometimes the fuel mixture can catch on fire in the cylinder way too early and then you have a huge explosion while the piston is still coming up, fighting it, and can cause catastrophic engine damage..
This can be from a glowing hot spark plug or just too much heat in the air when it is being compressed.. So you need higher octane to make sure it doesn't catch on fire on its own before you want it to by firing the sparkplug..




Regular gasoline displays these same features with increasing octane rating but to a lesser extent than going from gasoline to ethanol..




If you don't need high octane to keep your fuel from catching of fire before it is supposed to because you have you engine so hopped up, then you will get more power and better MPG with the lowest octane fuel your engine can handle..


the lower the octane the better unless you have a problem and need to make it harder to ignite..
Modern high compression engines and turbo/supercharged engines (which really just increase the dynamic compression ratio, FI)




So yeah, run that low octane crap in your low compression 454 for the best MPG and power..
Unless you hear it pinging/knocking, then you probably have carbon deposits on your head/piston top/valve surfaces that keeps glowing hot in between power strokes and/or increasing your compression ratio (taking up volume)..
In that case pull your heads and clean the carbon out of there, or try some magic that may or may not work like seafoam..
An engine will usually knock at peak torque RPM and lower..
You know that sound when you turn your distributor too far and it starts firing against the engine.. That's the sound to watch for..


Water injection is a darn good way of cleaning carbon too.. Steam clean..

Offline Rickf1985

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Re: Gas Mileage: 454
« Reply #156 on: August 14, 2018, 04:30 PM »
A good way to clean the carbon out of the cylinders is to force feed it water. Take the air cleaner off and get a 2 liter bottle of water. Warm the engine up to operating temp and then holding the water bottle in one hand and operating the throttle with the other, start raising the rpm and as you do start pouring the water down the carb. You will be trying to maintain the engine running at a around 1200-1500 rpm but you want to keep increasing the throttle and increasing the water as you do. This will keep the engine at the rpm mentioned. You don't want to open the secondaries but you do want to be close to full throttle on the primaries. Do this for about 15-20 seconds and taper off the water as you bring the throttle back. Then let it idle for a while to dry out the condensation that will have formed in the exhaust. Go for a ride afterwards to finish the drying. You are done. If you were to take the heads off at this point the pistons would look brand new, as would the heads. The one thing you have to be careful of is to not dump a whole bunch of water in and stall the engine. If it starts to stall stop the water. If it stalls and you keep dumping you can hydrolock the engine.

Offline TerryH

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Re: Gas Mileage: 454
« Reply #157 on: August 14, 2018, 05:37 PM »
Isn't that a form of torture? :)rotflmao :)rotflmao :)rotflmao

Offline Rickf1985

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Re: Gas Mileage: 454
« Reply #158 on: August 14, 2018, 05:54 PM »
Right from the manual. W%

Offline BrandonMc

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Re: Gas Mileage: 454
« Reply #159 on: August 15, 2018, 09:35 AM »

I'm no 454 expert, but..



learned something new today!


A good way to clean the carbon out of the cylinders is to force feed it water.


umm, wow that sounds crazy. my engine seems pretty tip top shape currently at 54,000mi

Offline Wkdemers

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Re: Gas Mileage: 454
« Reply #160 on: August 16, 2018, 12:37 AM »
https://www.livescience.com/58117-does-gasoline-go-bad.html




Google 'companies being sued for selling water contaminated gasoline'... They are messing with the gas, they know what they are doing and they are getting busted but not near enough and the media is hush-hush about it... The gas we buy today stinks! I have a 97 Expedition, a 98 Mustang V6, a F150 v6, and none of them run like they did years ago. Since that gas crash of 08 the American people have been getting scammed and robbed blind. There was one time I actually literally pumped several dollars worth of air! I didn't hear the gurgling of fuel entering my gas spout and decided to pull the nozzle out a little bit and still didn't hear anything I pulled it out some more until I knew there was nothing coming out and I pulled it all the way out and held it up in the air with the trigger pulled as I was watching the dial on the pump rack up dollars! We are being sold watered-down gasoline, gasoline 'cut' with ethanol (which draws water) who knows what other kind of fillers are being used to rip us off, we are just being ripped off. Just like in family law, CPS, got taxes for everything under the sun, cops waiting behind every corner to give you a ticket or find some fault with you or try to take your kids away inviting your wife to divorce you and rob you blind so they can get their cut. Anyways don't get me started. I wouldn't automatically suspect something wrong with your machine is what I'm saying.


Sorry about the rant guys, I know it's my first post and it's probably tacky but I've had it with three-piece-suit-wearing badge-flashing scam artists and feel it's my duty to call them out at every opportunity.


Thank you Jesus.



By the way I thought I might add this is in no way any kind of response to mr. Ricks post above, which I thought was interesting I've never tried that... If I do try it and it works, well I'll shut my mouth LOL

PS nice to meet you guys. I have a 93 Pace Arrow that I intend to do some work on and stumbled across this forum. :)
If I would have known then what I know now I wouldn't have knew what I now know! D:

Offline Wkdemers

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Re: Gas Mileage: 454
« Reply #161 on: August 16, 2018, 12:43 AM »
Oops
If I would have known then what I know now I wouldn't have knew what I now know! D:

Offline Rickf1985

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Re: Gas Mileage: 454
« Reply #162 on: August 16, 2018, 09:32 AM »
A good way to clean the carbon out of the cylinders is to force feed it water. Take the air cleaner off and get a 2 liter bottle of water. Warm the engine up to operating temp and then holding the water bottle in one hand and operating the throttle with the other, start raising the rpm and as you do start pouring the water down the carb. You will be trying to maintain the engine running at a around 1200-1500 rpm but you want to keep increasing the throttle and increasing the water as you do. This will keep the engine at the rpm mentioned. You don't want to open the secondaries but you do want to be close to full throttle on the primaries. Do this for about 15-20 seconds and taper off the water as you bring the throttle back. Then let it idle for a while to dry out the condensation that will have formed in the exhaust. Go for a ride afterwards to finish the drying. You are done. If you were to take the heads off at this point the pistons would look brand new, as would the heads. The one thing you have to be careful of is to not dump a whole bunch of water in and stall the engine. If it starts to stall stop the water. If it stalls and you keep dumping you can hydrolock the engine.


I did not intend for people to just go out and do this just to say they have a clean engine. This is something you do if you have symptoms of excess carbon in the cylinders like pinging when it shouldn't be or a cylinder with higher than normal compression.


Just running E10 gasoline will clean most of the deposits over time. Ethanol does have that one redeeming factor, it is a fantastic solvent. It is the main ingredient in all of the over the counter gas treatments so keep that in mind if you ever want to add a gas treatment to your car, you are probably already running it in the form of the gasoline.


Wkdemers, we have been getting ripped off by the gas companies since 1976. Ask Google to tell what happened then.  They own the government, not only here but in most oil producing countries so you are going to have to live with it.

Offline JohnM

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Re: Gas Mileage: 454
« Reply #163 on: August 19, 2018, 10:31 PM »
I'm tracking the mpg's for my 31' HRC Aluma-Lite XL here: 


http://www.fuelly.com/car/chevrolet/p30/1990/tmsnyder/454843


This is a 1989 454 with two air pumps removed, distributor re-curved, exhaust flow restrictions removed, Edelbrock 1406 carburetor.


Interesting. 86-87 Elandan, 28ft. Otherwise almost the same but no mods (yet). I think I get around 400 miles on a 55gal tank. That's about 7.2mpg. Just an estimate.

Offline tmsnyder

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Re: Gas Mileage: 454
« Reply #164 on: August 20, 2018, 08:01 AM »
Thanks, I do like that free website and if set up with texting it's easy to send it the odometer reading and the amount of gas pumped in.   Does all the math for you and keeps track of honest fuel mpg.   I think it's interesting how it varies.   That last fill-up was actually two lumped into one b/c I didn't fill it completely on the way home, tried to arrive completely empty so as to fill with non-ethanol fuel before parking it. 


Texting is just A B C D where A is the vehicle ID (a or b, I'm tracking 2 vehicles), B is the odometer reading, C is the gas price, and D is the gallons added.   Super easy and it immediately texts back the mpg for that tank.   They are trying to push a smart phone app, but I'm sticking with text messaging.



I've since changed to a 750 cfm Edelbrock 1411.  It climbs hills a lot better now than with the 600 cfm 1406.

Offline JohnM

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Re: Gas Mileage: 454
« Reply #165 on: August 20, 2018, 09:05 AM »
Thanks for replying, also from the other fellow. I appreciate it.  :)clap (forum needs a Thank You button)


I am on my way from Montana eventually down to TX, and I haven't quite made it to Colorado yet.


For you slow-goers on 80mph freeways: I really do drive around 45mph. I didn't want any idiot saying he couldn't see me. So on the top back of the Elandan, I put NAPA part... ugh NAPA's website is terrible. Insists on a a YMM/VIN before I browse the catalog. Ok, shoes on, climb up... Truck Lite part 22004Y. It's the 22-series with a gasket (to conform to the curved outer plastic) and the matching fitting for the wiring harness. You put the light up into position - use the 2nd screw down from the top vertical to reference position (see photo), mark the two fastener holes with a mechanical pencil with the lead extended (careful not to break, you only need a dot), pull it away, reduce your lead pencil to normal, and mark it better/cross it, drill a 1/8'ish hole. Drill a 1/2-3/4" hole in the middle for the wiring, and also, extend the kit wiring by 4 1/2 ft using B/R/W-colored wire (16 or 18 gauge). For drilling the center wiring hole, I use the fattest bit from the kit of those unstepped hole cutters (3x kit) from Hazard Fright, then angle it down when I've gotten to the bottom (the 'bottom' is the RV surface behind the plastic corner you are drilling through), so the 6' fish-tape will travel down more easily and pull through. See photo if I can get one uploaded. You'll run into an issue at the bottom where the beige plastic shroud inner-lip may block the fish-tape/wire, because of the clearance between it and the RV (take off the turn/brake 6x screws first, to remove the entire lighting assembly, and you'll see what i mean). Bring the tape around to the outside to bypass this, and you should be able to grab it and pull it through.


Once you do the above, check your grounds underneath, below on the chassis frame and replace the connectors if necessary. Also run new crimp wire loops (I also solder and liquid tape mine) to the end of the green ground wire, then to the screw on the back of the stock lighting assembly, not the original strip inbetween. Get rid of the strip and run another wire over to the backup light screw. The stock wiring on these is terrible. You lose ground and then the lights don't work.


But I digress. The crack-head way this was designed, means no one can see your stock red brake/turn/hazard indicators if you are towing anything or have bikes hanging off the back.


Eventually I will pull another wire from the front cab to the back, from the brake light switch, and take the brake-light system off the turn signal system, and the amber flashers will be just turn/hazard, with the stock red highs being only brake, and put a 3rd brake light below the 5x red clearance lights in the rear. I will also add the 22004R's (the red version of the amber ones I have installed) just below the amber ones, and those will be for brakes. [The clearance lights are not grounded right now until I figure out which of the original sockets is shorting to ground]


I've got the stock 16" steel wheels. I will inflate them to 75-80psi all around today. Also, I wonder about bag pressure.


I never ran with air in the bags. It was a comfy ride. When I did try air, it got too stiff, bouncy and crazy to handle. However, when I brought it into have it professionally re-aligned (prior to this I removed the dog-bones, the inner/outer tie-rods, cleaned them so they were easy to adjust, then approximated the setting just prior to having it done with the computer at the shop), I said there is too much weight in the back, but that I would be building a rack in the front, and moving weight to the front (spare tires with rims, not inflated), and otherwise some of the stuff in the back was for repairs/improvements on the RV, so as they got installed I would be losing weight/shifting weight, as well as giving a few things away.


So I'm sure he put air in the rear bags. I can check to see how much pressure is in them with a gauge. How do I know how much pressure I should have in them, though? I suspect he raised the back to get the chassis level prior to doing the alignment, and I don't want to throw the alignment off.

Offline Rickf1985

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Re: Gas Mileage: 454
« Reply #166 on: August 20, 2018, 09:13 AM »
You will have to get it realigned once you get the weight redistributed. Any change in front ride height also changes both the camber and also the toe in. And if you change the angle of the coach from front to rear too much that will affect the castor but not too a great degree. That would just be something that would be addressed if a complete realignment was done.

Offline JohnM

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Re: Gas Mileage: 454
« Reply #167 on: August 20, 2018, 05:27 PM »
Thanks.


Can you comment: I looked at the plate on the inside of the driver's door, and it says 60PSI.

I am thinking about going to 75PSI based on what I have read here.


Thanks for the information about the alignment issue. It will just have to wait until I have another $100 to sink into a re-alignment (that's how much I was charged in Billings). It took them less than 10-15 minutes, because I had done all the cleanup work, the de-rusting, greasing etc. But it's a flat rate for them. Rapid Tire in Laurel would have been cheaper (suburb of Billings).

Offline JohnM

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I lul'ed when I read this:
« Reply #168 on: August 20, 2018, 06:02 PM »
Getting to a 14:1 or 15:1 ratio instead of 'dumping gas' at a 11 or 10:1 http://www.superchevy.com/how-to/engines-drivetrain/0510ch-carburetor-tuning-gas-mileage/


Requires merely a $600 diagnostic tool.


Other than that, parts are cheap.


Anyone handy near Boulder?

Offline JohnM

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Iridium plugs
« Reply #169 on: August 20, 2018, 06:15 PM »
Also, I am a big fan of the NGK Iridiums. Besides pulling an existing plug, do you know what the stock/suggested plugs are in here, so I can look up the iridium replacement?


Edit: Rockauto lists 3 different NGK/Denso's: 5330 POWER, 4517 TT, and  7516 IX


Ah, it looks like the TT. The IX is the original iridium design, while the TT has a tougher ground electrode.

Offline Rickf1985

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Re: Gas Mileage: 454
« Reply #170 on: August 20, 2018, 09:00 PM »
John, I can tell you from many years of experience that those plugs will work great in small foreign engines but for the most part they will run no better and a lot of the time they will run worse in big American engines. Ever try putting those plugs in a 4.0 Jeep engine? It will not idle and no acceleration, never fails. I run 75lbs in my tires all the way around. That is where I found that they like to run and stay at a decent temperature. I run the Samsons which do not list a weight to pressure chart but most big tire companies will give you a chart that tells you what pressure to run the tire at based on the scaled weight reading. I guarantee you are not running 10 or 11 to 1 anytime other than hard acceleration. If you were you would be belching black smoke. I don't know what diagnostic tool you are talking about but you can buy a wide band A/F meter for 100.00 and install it on your dash so you can see your mixture in real time. A 454 moving a barn down the road is never going to get anything better then 8-10 MPG and to get that you are going to have to change the cam, intake manifold, carburetor and add headers. The money that is going to cost you will buy a LOT of gas at 8 MPG so how much do you actually drive and will you drive enough to earn back that money at the extra 2--3 MPG you will gain?

Offline LJ-TJ

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Re: Gas Mileage: 454
« Reply #171 on: August 20, 2018, 09:30 PM »
Well said Rick :)ThmbUp

Offline tmsnyder

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Re: Gas Mileage: 454
« Reply #172 on: August 21, 2018, 10:13 AM »
I started tracking my mileage on 7/7/16.   Since then I've driven it 15,738 miles.  I've spent $5730 in fuel at an average of 7.4 mpg. 


If I could get that to 8.4 mpg, it would have resulted in a $682 savings in gas.  A $200 A/F meter is on my to-do list, b/c I would like to tune the carburetor but I'm stuck at getting the exhaust pipe off and welding on the bung.  Just can't seem to get myself under there to do it.


I'm also thinking about folding up some DIY air tabs and see what that does :)


My tires are load range F, 110psi tires, I run them at 90psi.  I'm afraid to run them any lower b/c I don't want them to get hot.  The coach sticker says to run them at something low, like 50 or 60, but it originally had load range D tires.  Try finding 8R19.5 tires in LR D, good luck!




Offline fasteddie313

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Re: I lul'ed when I read this:
« Reply #173 on: August 21, 2018, 12:20 PM »
Getting to a 14:1 or 15:1 ratio instead of 'dumping gas' at a 11 or 10:1 http://www.superchevy.com/how-to/engines-drivetrain/0510ch-carburetor-tuning-gas-mileage/


Requires merely a $600 diagnostic tool.


Other than that, parts are cheap.


Anyone handy near Boulder?




I have the innovate MTX-L
https://www.ebay.com/p/Innovate-3918-Mtx-l-Plus-Wideband-O2-AFR-Air-Fuel-Ratio-Gauge-Kit-Bosch-Lsu4-9/2214678600?iid=272697199421&chn=ps


$160 and has a gauge..


If I am to ever trust the old carb'd 454 on a very long trip surely I will put the wideband on it.. For reliability reasons..


For one, if you are too rich in mixture not only will you be getting terrible gas mileage and less power (for the same air), but a very rich mixture, especially at long idles, can really decrease the lifespan of your piston rings..


The cylinder walls are supposed to keep a nice oil film on them but you can run too rich to where the gasoline washed the cylinder walls clean constantly and basically it will wear out your rings..


For two, lean can kill your engine.. You could be pulling a big hill and not know how lean you are, and melt pistons, burn valves, get hot, etc..


The 454 will probably run with a wide open throttle at 16:1 and not miss or chug but have crap power and suffer possible engine damage..


If you try to pull a big hill with an engine that isn't running right, that is a good way to blow an engine..


For three, yeah I would want to get good gas mileage so I would want to know what my cruise AFRs are..
If they are too lean then thier is a problem that needs to be fixed, leaner than 15:1..
If it's overly rich then you would just be throwing away gasoline..


I expect a carb to run just on the rich, safe, side, everywhere..


I think a nice 3/8 intake manifold vacuum line to a ball valve for an on-the-fly unmetered vacuum leak would be a good way to lean out your cruise real-time..
If your cruising at 13.5:1 open the valve a crack until you are 14.5-15:1 and cruise away at a nice AFR adjustable to elevation and everything.. Just close it when you go to put down power..
That's your crazy idea for the day..




Do you just trust your carb? I don't.. For all I know it's just good enough to make me think it runs fine but in secret it is conspiring to blow up my engine if I ever need to floor it for more than a few seconds..


I don't think I would trust it without knowing my AFR..


I think a 454 is going to be more resilient to poor AFR than most engines.. It probably isn't going to knock and blow up just due to poor AFR like some engines will, but a poor tune, bad AFRs, decrease the lifespan of your engine in general..


A good tune VS a poor tune could mean the difference between a 75,000 mile 454 life to a 150,000 mile 454 life.. 

Offline fasteddie313

  • *
  • Posts: 134
  • Member since: 2015
  • I own: a Motor Home
  • Year: 1981
  • Make: Holiday Rambler
  • Model: Imperial 33
  • Chassis: Chevy
  • Engine: 454
Re: Gas Mileage: 454
« Reply #174 on: August 21, 2018, 12:57 PM »
Spark plugs to my understanding..


Iridium and other fancy metals are for extended service life..
If you want your plugs to last 50,000 miles, 100,000 miles? or so in your low maintenance grocery getter, iridium is for you.. 
Or if you have one of those vehicles where you have to move the engine to change your plugs, iridium yep..


Good old copper plugs..
They transfer heat the best which is important if you need to resist detonation.
They transfer electricity the best.. They are the best for performance engines..
1,000 LS engines and 500HP honda engines will be running copper plugs..
Racers will be running copper plugs..
But they last something like 10k-20k miles.. Less than iridium, but iridium electrodes will glow red hot and cause detonation in at-the-limit applications.. The hard tips sometimes break off and destroy cylinder walls, scratch it all to heck..


Some engines just hate certain plugs.. No real reason..
I tried some split electrode bosh plugs in my M3 and they instantly ruined the idle.. Put the old plugs back in and all was well again..


Spark plug heat range.. Pretty much a balance of how clean your plugs stay VS how cold they stay.. How well they transfer heat from the tip to the head so they don't overheat..


If you don't transfer enough heat out of the end of the spark plug then it will glow red hot and cause detonation/preignition/knock..


If you trasfer too much heat out of the spark plug to the head then it will stay too cold and never get up to a high enough tempature to burn the carbon off of them, and foul out..


It really depends on how hot of a condition you are creating in your cylinder..
If you have just small port heads you aren't getting that much air for that big of an explosion so it's never going to get all that hot.. Maybe a 5 6 or 7 NGK heat range plug?
Put a big valve head on the engine then  your getting more air.. Run boost then you are adding more air.. More air more power more heat.. Probably an NGK 7 for a big valve 454 up to 8s 9s or 10s if you run a turbo or supercharger..


I don't know what they recommend for the 454 stock, am I close?
NGK says YR5 plugs for 1981 P30 7.4.. Heat range 5..
That's a pretty hot running plug for a pretty cold running engine, the right match.. For a hot engine you need a plug that runs colder, sheds more heat..




Common knowledge is to run the coldest plug you can without them fouling out..
I'm not sure if/how that applies to a very low tuned engine that needs hot plugs though.. Probably just do what NGK says..


As far as pouring water in the carb to clean out carbon..
I don't doubt a bit that it will work but seems pretty dangerous to hydrolock if you pour too much.. IDK how much is too much..

I would probably atleast try to spray, mist, or steam in into there.. Start small checking your spark plugs and you will know when you have added enough water enough when your spark plugs look brand new..

454 might be able to chug through quite a bit of water.. Boiling water may be better?

I think the cleaning mostly comes from when the water is gassed into steam when the cylinder fires..


I cleaned the carb and put a new gasket and choke on my 454 but I haven't really dug into the BBC specific education yet..
I just like talking engines..

 

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