Hi all , new to this . First time out. I have a older motor home with a 454 motor . thinking i should install headers, high input air cleaner , new exhaust in hopes of better milage, better performance . it does run nice, and only has 39000 miles. any ideas on this . thanks Ron......
My mothers maiden name was Angus. Sounds like a lot of money for a little gain. Feed cold air to your air cleaner and you will probably get about as much gain .
For best gas mileage cruise at lower speeds like 55-60 mph. gas mileage decreases dramatically for every mph. We went from 4-5mpg to 7-8 by traveling at 60 mph or less. I like Richards comments too. This big block needs tons of cold air and as much cooling as you can get to it. They are notorious for running hot.
Headers can become a problem from leaks and rust out.Cast iron manifolds are much more reliable and even these can be improved by using aftermarket cast iron manifolds made by Ring.
hey Jimco thanks for the reply . are these manifolds made with better air flow then stock?
Probably not, but you will get no gain from headers on a motorhome. Headers only make a difference at above 3500 rpm. Keep your foot out of the accelorator and you might get one more mile per gallon.
I purchased a 1984 Winnebago Chieftain on a P30 chassis with a 454 and TH400. The previous owner had installed a Banks Power Pack. Basically, it is a cold air intake, high flow, cleanable air filter, headers and a muffler. It has been my experience that my mileage (7.5-9 mpg average) is about a half to one mile to the gallon better than my in laws 1986 Windcruiser. Both motor homes are roughly the same weight with the same chassis, engine, trans and running gear. On top of my mileage being slightly better they do not stand a chance against us on a 5% + grade. We traveled together on a trip from northern California to Southern California and we were able to accelerate up the grapevine (steep section of highway on I-5 in California) without any issues. They couldn't even maintain their speed and ended up climbing most of the grade at around 35-40 mph. So, the combination of the cold air and increased flow must provide some benefit. The question though is it worth $1800 to you. This seems to be the going rate for the Banks Power Pack System. Do to our limited use of the motor home I don't think that I could justify the cost, but if you were a full timer that could be a saving of as much as 12% at the pump. So, if you are driving a lot of miles then you may repay your investment. I do absolutely agree with driving at a slower speed especially if you have a NON overdrive transmission. We don't drive over 55mph unless gravity is providing the extra momentum. I have heard a lot of positive feed back on various forums about a tri-y style header that helps increase flow and provides some addition boost with mid range torque, which is where you would need it on motor homes like ours. Our cruising RPM at 55mph is around 2500rpm.
Test vehicle: 31-foot GM 7.4L motorhome, P-30 chassis, throttle-body injected
Horsepower and torque measured at rear wheels.
|Horsepower, best gain||142.9 hp (4400 rpm)||221.4 hp (4400 rpm)||+78.5 horsepower||55% more (4400 rpm)|
|Horsepower, peak-to-peak||177.0 hp (3300 rpm)||233.3 hp (4000 rpm)||+56.3 horsepower||32% more, peak-to-peak|
|Horsepower, upshift point (at wide-open throttle)||146.0 hp (4300 rpm)||224.0 hp (4300 rpm)||+78.0 horsepower||53% more (4300 rpm)|
|Torque, best gain||186.8 lb-ft (4200 rpm)||283.1 lb-ft (4200 rpm)||+96.3 lb-ft torque||52% more (4200 rpm)|
|Torque, peak-to-peak||342.3 lb-ft (1800 rpm)||402.9 lb-ft (1800 rpm)||+60.6 lb-ft torque||18% more, peak-to-peak|
|Torque, downshift point (at wide-open throttle)||312.1 lb-ft (2600 rpm)||393.5 lb-ft (2600 rpm)||+81.4 lb-ft torque||26% more (2600 rpm)|
|Exhaust gas temperature||1,552°F||1,388°F||-164°F||11% cooler|
|Exhaust backpressure (at equal airflow)||7.5 psi||0.75 psi||-6.75 psi||90% less backpressure|
|Air cleaner vacuum (at equal horsepower)||17.0 in/H2O||2.4 in/H2O||-14.6 in/H2O||86% less restriction|
|0-60 mph acceleration, time||24.19 sec||18.38 sec||-5.81 sec||24% quicker|
|0-60 mph acceleration, distance||1,325 ft||1,008 ft||-317 ft||24% less distance|
|40-60 mph acceleration, time||12.73 sec||9.42 sec||-3.31 sec||26% quicker|
|Maximum speed, hill-climb (6% grade)||57 mph||68 mph||+11 mph||19% faster|
|Fuel economy (over 7,000-mile test route)||6.90 mpg||8.25 mpg||+1.35 mpg||20% better mileage|
|+64 lb-ft torque|
|11% better mileage|
Hi Chris thanks for the reply, you are right, I talked to banks yesterday and they claim a 20% increase in fuel mileage. but now the price is 2100-2400. i think i am going to do the air and exhaust for now and see what that does. money is a issue. my motor home is a 1985 winnebago33' chieftain. like yours it sounds like. so i have a shelf looking board that i cant figure out where it goes. i thought maybe it went in the wardrobe closet but its longer then that. any ideas on what this could be for? Thanks Ron........
Like I had mentioned the previous owner had the Banks Power Pack installed, with our limited use I just couldn't justify the $1800 he paid let alone the $2100-$2400 that you were quoted. I also got lucky because he had installed a HWH hydraulic leveling system. That wasn't something that was on our needs list when we were looking, but I don't think we could live without it now...lol. As for the shelf, I'm not sure. Here is a link to a photo of our wardrobe: http://www.goodoldrvs.com/photo/s031-custom-drawer-in-the-hall-pant... Do you have a way to take a photo and send it to me? If so I'll send you a PM with my email address. If you can send me a photo there is a good chance that I'll know were it goes. We've completely tore every inch of our motor home apart at one time or another.