Anyone ... MAX-mpg V8 project "chat" ?

[Doc]

any interest out there ? ..... I have a couple of older Dodge chassised motorhomes that are NOT real mpg-champs. I am looking to put-together a 413 with a LOT more compression, better fuel delivery system, cylinder heads and camshaft.

I have some ideas .. but no real experience past changing the intake and carb on this application ...which helped a TON.

[Rolling_Thunder]

what r u looking for exactly ?  build a 413 for a charger or something and get great MPG ?     be specific in what you want and i'm sure we can help.

[Doc]

? ....... The questions you asked ...are explained in the original post.

And "chat" like this can be applied to anything ...a street car, tow rig --- even a max-mpg daily-driver project. 

[Rolling_Thunder]

ok - well without knowing any particular body style your "best MPG" scenario comes from a mild rear end gear, overdrive transmission, and EFI.   

with a 413 block you can use any 440 intake manifold - Edelbrock makes a pretty sweet EFI intake - I have used it on my 440 and it works great...        a speed density system is good due to being able to trim the fuel curve for economy or power. for a 550hp engine run 36lb - 42lb injectors. 1000-1250cfm throttle body and a decent camshaft matched to your torque convertor and gears...     run 3.23 or 3.55 gears with a TKO-600/T-56 or a TF727 with a gear vendors unit.   

[Doc]

I have a fairly small motorhome ... but it could weigh as much as nearly 20k !!

And Eddie EFI manifold ? ... and how is that Eddie FI system? ... I hear that there is almost zero customer-service from Eddie on this system.

[Rolling_Thunder]

I have a fairly small motorhome ... but it could weigh as much as nearly 20k !!

And Eddie EFI manifold ? ... and how is that Eddie FI system? ... I hear that there is almost zero customer-service from Eddie on this system.

never dealt with their pro-tuner kit as i dont like it. I perfer complete stand alones...    i have heard it is very user friendly however.

[2Gunz]

You would prolly be better off pulling or buying a newer engine out of a wrecked truck.

A gear vendors overdrive is going to cost 3 grand +

Aftermarket EFI also isnt cheap , I dont know how much but I would suspect also over 3 grand.

So thats 6 Grand just to get started......


Some ebay listings for you.......

http://cgi.ebay.com/ebaymotors/2006-DODGE-CHARGER-HEMI-ENGINE-TRANSMISSION-REAR-END_W0QQcmdZViewItemQQcategoryZ46098QQihZ012QQitemZ220250926357QQrdZ1QQsspagenameZWDVW

http://cgi.ebay.com/ebaymotors/2004-04-DODGE-RAM-1500-4X4-5-7-V8-ENGINE-TRANSMISSION_W0QQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247QQcategoryZ33615QQihZ005QQitemZ150212195322QQrdZ1QQsspagenameZWD1V

http://cgi.ebay.com/ebaymotors/03-04-2003-2004-DODGE-RAM-5-7-HEMI-ENGINE-TRANSMISSION_W0QQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247QQcategoryZ33615QQihZ004QQitemZ140203913707QQrdZ1QQsspagenameZWD1V



Good luck

[Doc]

R T .... stand-alones ?

2 ...  Those motors you list have decent HP ... but they are quite lacking in torque. PLUS ... it would be a horror show with the electronics that is on those motors. A GV OD is not needed ...I plan on changing the rear gear from a 4.56 to a 3.73. And at 60 mph ... I should be running be at about 2,800 rpm. The EFI ? ... I think after hearing about all the issues with these systems ...I will stick with my trusty TQ.

Attached is a photo of my project .. tell me what you think ...

[Rolling_Thunder]

ok - so just build a torque monster big block - i'm sure you'll get 10mpg out of it 

[Doc]

I am getting about 10 mpg now ... gotta get better !

[Rolling_Thunder]

I am getting about 10 mpg now ... gotta get better !

See above comments.     If you want to run a 727 and a carb you wont get much better than that.

[Doc]

So ........ adding almost 3 points of compression ratio, introducing water-injection to be able to add another 3-5 degrees timing, reducing the gear ratio by almost a full point, doing some severe head work, adding a 2008 "tech" cam will not help ?

You are suggesting adding a GV and EFI ? ..... IMO ..no gas motor short of a 500 incher on premium gas could pull a 3.73 gear with the GV overdrive....especially when you consider that the GVW might be close to 20k pounds !! ....  The EFI ? ... show me one that does not have major issues and I will consider it.

I am MORE than willing to spend some serious bucks here. Some people who are involved in the RV hobby are spending up to 3k$ per month ...on just depreciation ...on their motorhome.

[Rolling_Thunder]

adding Compression will just necessitate higher octane gasoline...    go 10.5:1 with water injection...      still you'd be running 92 octane with aluminum heads...    as motorhomes are alot of weight - it will greatly load the engine...    making it prone to detonation.

The GV unit - I would assume your transmission will stay in the lower gears while it is getting underway - but once you are cruising at 65mph or so wouldnt the engine be under alot less strain and an OD gear be acceptable  (Motorhomes really are not my thing - so correct me if i have any flaw in my logic)

EFI - systems that work very well -  FAST and BS3 come to mind...     these are just the controllers however - you would need to source intake, fuel system, injectors, throttle body, ect - per your application.

[Doc]

Adding compression will make more power ....and allow the motor to pull more weight(and it be EZier) at lower rpms. My thoughts are to use a flat-top pistons(instead of the huge dished ones) ....to clean up the combustion chamber and maybe increase the CC's to get something like 10 to 1 or so. The water-injection "cures" any detonation problems. My primary concern is the rpm range of 800-3200.

The FI system ? ... does not seem to be in-the-cards for me. UNLESS someone would guarantee a large cost-benefit ratio.

[2Gunz]

Most of the stuff you are talking about isnt going to help much if any with your MPG.

The exception would be the taller rear gears.

I think your wasting your time IF your goal is better gas mileage.

My vote is still a newer engine and tranny.

And you dont need torque if you have gears.

[Doc]

2 ...... better heads(that will insure a more complete mixture of the A/F), a 2008 cam, more compression(to burn that A/F more effectively) ...does not equal a bunch more MPG to you  ?