Have you seen this? Add 231 Horsepower to a Motorhome Engine With Bolt-On Parts!

[BrandonMc]

I want to see how the Engine and Coach were all put back together!

story:
http://www.hotrod.com/articles/bolt-230-horsepower-454ci-motor-home-big-block/

video:
https://www.youtube.com/watch?v=JG438976rK8


When HOT ROD Magazine friend, Curtis Mowery, brought home a free '86 GMC motorhome to use as a "donor car" for an upcoming project, we decided to treat it to some speed parts and see what kind of horsepower the 454ci big-block could really make. Stay tuned for the full story on www.hotrod.com

[Rickf1985]

The engine went in a pick up and the coach went in a dumpster. Looking at that dyno pull sheet you can see the torque is lower than stock all the way up to about 4,000 RPM. That thing would be a dog in a motorhome! BUT, You notice that they gained more power when they went to regular gas. I tell people this all time when they think they have to run premium in a low compression engine to get it to run better. There is more power in regular gas.

[MotorPro]

$3700 to give less usable power in an rv. Would have been cheaper to buy a crate engine or even better have a reputable shop do up a good set of stock heads an rv cam and a good intake and carb. Oh but then that would not have been a paid ad for trick flow . Would it?

[tmsnyder]

They got the engine out of an RV, putting it in a street rod (truck). 

[fasteddie313]

https://www.ebay.com/itm/BBC-TWIN-TURBO-KIT-BIG-BLOCK-572-502-454-427-396-BIGGEST-MUSCLE-CAR-RACE-SETUP/272117618352?hash=item3f5b7956b0:g:4LAAAOSwFMZWqUIP

https://www.youtube.com/watch?v=oFLqaSNp45Q

Then look at this through your homemade bulletproof glass doghouse cover..

[Rickf1985]

I love the quote that Steve makes at the end. "The best thing about it is the oil is still in it"
To me that kit is worthless to the average person. Even if they got it all hooked up some how the first time they romped on it and the boost went to 18-20 lbs the crank would have made a new window in the oil pan. Joe average is not going to be in a dyno room with a super experienced dyno operator, he is going to jump in and stomp on it and hold it there and see what she does. BOOM, rattle, rattle, BOOM.

[ErikTande]

I want to see how the Engine and Coach were all put back together!

story:
http://www.hotrod.com/articles/bolt-230-horsepower-454ci-motor-home-big-block/

video:
https://www.youtube.com/watch?v=JG438976rK8


When HOT ROD Magazine friend, Curtis Mowery, brought home a free '86 GMC motorhome to use as a "donor car" for an upcoming project, we decided to treat it to some speed parts and see what kind of horsepower the 454ci big-block could really make. Stay tuned for the full story on www.hotrod.com

A bunch of the youtube comments wanted to see what the motorhome would run, so I made this video of mine ^_^
https://youtu.be/Y79YaQ1lHaY

[M & J]

 

[Rickf1985]

I'll have to check but I am pretty sure I get up to sixty in less than 24 seconds. Maybe not, I am not really timing it but I blend in on the interstate pretty well.

[Rickf1985]

https://www.youtube.com/watch?v=Q9dFZDt1mPY


https://www.youtube.com/watch?v=wap2wpjVHC0

[ErikTande]

I'll have to check but I am pretty sure I get up to sixty in less than 24 seconds. Maybe not, I am not really timing it but I blend in on the interstate pretty well.

Keep in mind that run was at a density altitude of 8500' above sea level.   There's no air up here  ; )

[Rickf1985]

This is very true. I give you credit for even having the gonads to run your motor home down the track! I worked as a starter at a local racetrack for a long time and I saw all kinds of strange things go down the track but never a motor home! Of coarse it is no different from taking off from a light on the highway really.

[Sasquatch]

Good thread.  I have been doing research on what to do with my motor when I rebuild it.  All the usual items have come to mind like higher compression pistons, aluminum heads, etc.  But I just do not know how much real world improvement I would get in an RV vs. the cost to do it.

One of the things that keeps nagging my brain is a low boost turbo system.  I am already running a low compression engine that would handle 5-8 psi of boost without any issue at all.  I also have the ignition system that can handle the timing issues and the fuel injection system is set up to handle boost, so it would just be bolting up the hardware and tuning it.  But again, what am I going to realistically gain in an RV vs. the cost/time investment?  Probably not enough to actually do it.

She already pulls hills plenty fast, cruises at 70 comfortably, and will outrun dad's 625hp diesel pusher on mountain passes or pulling away from a light (but he weighs 45k lbs).  I would love to see what she would do in a 1/4 mile for giggles.

[Rickf1985]

Keep in mind that while you have low compression you also have a large cylinder volume so when you add that 5-8 lbs. of boost you are actually raising your effective compression up into the 12:1 range due to the high volume you are compressing. 454's have issues with head gaskets as it is so you might have to O-Ring it and then you are going to have to run premium or higher gas.

[Sasquatch]

You are right Rick.  Probably not going to do anything but throw in some flat top pistons and clean up the heads a bit.  Just live with what I get.  She runs so good now I really dont need much.

[Rickf1985]

I said 454 problems with head gaskets but forgot you have a 440.

[Froggy1936]

My 2c worth is there are very few things you can do to improve MPG Or Power over properly tuned stock , That are worth the time and expense . Upgrading to a diesel is the exception . That is about the only thing that will improve MPG for the effort involved  , If you want to see what i have done visit my gallery and look at the projects section , All of that has not made much difference driving @ 65 MPH ! Frank

[Sasquatch]

With all the upgrades I have done to my 440 over the years, power and drivability increased quite a bit.  Fuel economy went up some, but not a lot.  When I got it (and it was in excellent, highly maintained state) from my father it ran great, but power was lacking.  It got a solid 5.5 to 6.5 mpg average.  Climbing over the Blues heading to the coast I would regularly pull the big hills at 40-45 mph.

Fast forward 22 years and the addition of Headers/exhaust, intake, electronic ignition, fuel injection, emissions removal, mechanical to electric fan swap, new cam, and I am sure a few other mods the coach will pull the same mountains rarely even needing to downshift or drop below 50-55 mph all while getting mileage averaging in the 7-7.5 mpg range.  So a gain of 2 mpg and at least 10 mph climbing the same mountains.  Jury is still out on my overdrive swap as I have not had the chance to really prove it on a trip.

Now, was the gains worth all the $$ invested and time?  If I did all the mods at once, the answer would be heck no.  But since I did them slowly over 22 years, I would say yes.  The single best mod, by far, was the fuel injection system.  It made such a huge difference in how the coach ran that it was worth every penny of the $2k I invested (you can get the same type of kit now for around $1k).  I would NEVER go back to a carb.  And my carb was well set up.  But the difference, especially with today's fuel was striking.

[ErikTande]

With all the upgrades I have done to my 440 over the years, power and drivability increased quite a bit.  Fuel economy went up some, but not a lot.  When I got it (and it was in excellent, highly maintained state) from my father it ran great, but power was lacking.  It got a solid 5.5 to 6.5 mpg average.  Climbing over the Blues heading to the coast I would regularly pull the big hills at 40-45 mph.

Fast forward 22 years and the addition of Headers/exhaust, intake, electronic ignition, fuel injection, emissions removal, mechanical to electric fan swap, new cam, and I am sure a few other mods the coach will pull the same mountains rarely even needing to downshift or drop below 50-55 mph all while getting mileage averaging in the 7-7.5 mpg range.  So a gain of 2 mpg and at least 10 mph climbing the same mountains.  Jury is still out on my overdrive swap as I have not had the chance to really prove it on a trip.

Now, was the gains worth all the $$ invested and time?  If I did all the mods at once, the answer would be heck no.  But since I did them slowly over 22 years, I would say yes.  The single best mod, by far, was the fuel injection system.  It made such a huge difference in how the coach ran that it was worth every penny of the $2k I invested (you can get the same type of kit now for around $1k).  I would NEVER go back to a carb.  And my carb was well set up.  But the difference, especially with today's fuel was striking.

What's a good bolt on EFI kit for a 1985 454?

[Sasquatch]

I would stick with one of the big companies like Edelbrock or Holly.  I chose Professional Products when I did mine 8 years ago and they no longer support it.  While it works great, and I love some of the features, long term support is important.  So if it fails, I will do research on what the current offerings from Edelbrock and Holly are.  FiTech has great reviews, but I am worried if we go through another big depression will the small players survive?


These bolt on kits have gotten pretty darn good.  Even though mine is older, it is still self learning and uses a wide band O2.  Instant starts and it runs perfect no matter the altitude, loads, temps, humidity, or fuel grade.  It just works.  With the carb, I could jet it perfectly at home (2600') but then the jetting is off if I go up or down. 


I have preached this before.  If you love your rig and use it, put a kit on it and never look back at carbs.  A well set up carb will work almost as well, but how often is your carb well set up?  Did you jet it on a dyno with an exhaust analyzer then never change altitude or temps when you drive?  Doubt it.  FI constantly adjusts for conditions.

[YetAnotherMike]

What's a good bolt on EFI kit for a 1985 454?

I'd be interested in that as well...
I have an '86 Fleetwood with a 454. 
And any kit I installed would need to have California smog approval.

BTW a friend has a older Suburban with a carbureted 454.  The biggest
improvements for him was  headers, an MSD ignition and an RV cam (in
that sequence).   He went from 9-10 mpg to about 14.

[Rickf1985]

I'd be interested in that as well...
I have an '86 Fleetwood with a 454. 
And any kit I installed would need to have California smog approval.

BTW a friend has a older Suburban with a carbureted 454.  The biggest
improvements for him was  headers, an MSD ignition and an RV cam (in
that sequence).   He went from 9-10 mpg to about 14.

You are pretty much screwed! You are going to have to retain ALL of the original emissions equipment and I seriously doubt any of the fuel injection throttle bodies are set up for that. You could ad headers and and RV cam and an Edelbrock carburetor. They are all CARB. exempt. The Edelbrock will have all of the vacuum fittings you need to hook up to your emissions stuff. That said, there is absolutely nothing wrong with a Quadrajet carburetor if it is in good shape. If yours needs rebuilding try to find a shop with an older mechanic who is experienced in them. There should be plenty of those guys out there if you look in the hot rod scene. And they will also know how to set it up to run just right. The MSD is a good setup but so is the factory HEI. A lot of people just want to change it because it is original "so it can't be any good". Well, GM did get some things right guys and HEI was one of them. I am not all that familiar with what you can get by with in Cali. on modifications but I do know you cannot do anything to affect the emissions so changing the timing is out. I was going to suggest calling the guys at Davis Unified Ignition for a custom set up distributor. You can still call them and they can tell you if it is legal or not.

[BrandonMc]

That said, there is absolutely nothing wrong with a Quadrajet carburetor if it is in good shape. If yours needs rebuilding try to find a shop with an older mechanic who is experienced in them. There should be plenty of those guys out there if you look in the hot rod scene. And they will also know how to set it up to run just right.

Good to know that's your opinion on the quadrajet, because I've been trying my damnedest to isolate a vaporlock issue and replacing the carburetor seems like an unnecessary expense. About going the Fuel Injection route and just can't justify it.   

[Rickf1985]

Check your rear tank fuel pump, also check the fuel pressure at the filter midway between the back and the front. The regulator may not be working and restricting the fuel. Also check the condition of the mechanical pump mounted on the engine. And make SURE you replace that filter at the midpoint in the line.

[MotorPro]

Mine would act like a vapor problem climbing hills.. Turned out to be a fuel pump relay. Now climbs like a champ.