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scotta · 03-16-2003, 08:04 AM

I own a 1995 Airstream Land Yacht with a 454 Chevy gasoline engine. I would like to know how I can improve the hill climbing ability of this engine? I would appreciate any and all advice you can offer.

PeterH-350LE · 03-16-2003, 08:44 AM

Have you looked into Banks exhaust system

evan · 03-16-2003, 08:45 AM

If you have the money to spend, I have heard the Banks Power system provides a big boost 25-35% over stock. The system cost around $2300-2500 installed for the 454. Gearing can provide a large felt power boost. Gear Venders under/overdrive secondary gearbox can give you the needed torque and gearing for both hill climbing and passing. Also lower RPM for better gas milage when cruising on flat ground. Camping world has these for about $3000 installed. Here are a couple of lower costs tricks I have found to be very effective. #1 get rid of the stock airbox and go with a " cold air" system. They make these kits for all sorts of vehical types and they are very effective. At the very least put a K & N drop in filter into your stock cleaner/airbox. Look into a less restrictive muffler system such as Banks ( you can find much cheaper) These are called "Cat-Back" systems meaning you replace everything from the catalytic converter back to the muffler-tip. High performance "fat" low resistance plug wires and a high output coil along with better grade spark plugs such as Bosch platinum multi-tips. Better yet, Jacobs sells a electronic ignition kit with all of the above along with a Digital ignition control. About $350 at Camping world.

Silvertwinkie · 03-16-2003, 09:50 AM

There are several things that can be done. Intake (air filter, etc), Mass Airflow Sensor, exhaust (dual), headers, engine management programming to the air/fuel ratios and gears would be my first changes to make. It is not uncommont to have done all the mods listed above and gained about 25-30hp.

More involoved mods would be cam, lifters, rockers, machined heads. Those would be good for another 30+HP depending on how wild you went with the cam (also depending on cam, you may need to upgrade fuel pump and injectors).

There are a bunch of us speed junkies out there that do these mods for speed, however, most could be used to add HP and torque for towing. It's not uncommon for someone with a 454 to get the engine to produce 450-500hp.

Power costs money. How powerful do you want to go? I would not spend $2000 on an exhaust system. I'd put maybe $800 to $1000 toward a good one and invest the rest in other componants.

Regards,

Eric

P.S- whatever you do, don't believe everything you hear on how much a product will increase HP and torque. I looked at that Banks site and also from my exp with other exhaust manufac.

Bottom line is that those figures are rarely real world application. A good exhaust system (duals) will only yield 20-30hp max alone. I would want to see dynod tests done in front of me to prove otherwise. Great headers will yield about 25-30hp. Average to minor improvment over stock will only yield about 10hp.

Pahaska · 03-16-2003, 04:59 PM

I have the Banks system plus the Granatelli mass airflow sensor on my SIlverado 5.3. The combination has changed towing from a chore to a pleasure.

59toaster · 03-16-2003, 06:05 PM

http://www.customefis.com/
This guy knows his stuff when it comes to GM FI. There may be some minor tweeking of the computer that can be done. His site is deliberatly lack luster. He's just about the meat and patatoes of things.
If you have alot of miles then change the O2 sensor. They have a replace schedual of 60k on 350's. It may be as low as 30k on the 454. Check your owners manual. These are designed to go rich as the fail. Rich is less likely to dmage the engine then lean.
Now one thing you need to do is fill us in here on a few things.
WHere the heck are you? If you having problems with hills on 10,000 ft passes in western Colorado there may be nothing wrong with the engine other than thin air. The same engine will have more pwoer at seal evel then it would at 10,000ft...A BIG difference.
Anyway John at Custom EFI's is a wiz and has some software and interface cables so that you could hook into your FI and get some real time data driving around. On the Pre OBDII FI he can custom tailor a Chip and get significant gains in both power and MPG.
Like other said do some things to help the engine breath a little better as well. But once you have done those changes then you can fine tune the FI to take beast advantage of it.
I'm currently shopping for a 454 Burb and it's my intention to get with John and do some fine tuning. I'm close enough that I may just run down there. I'm looking into one of his systems to retrofit into my 1975 Jimmy.

autoist · 03-16-2003, 09:11 PM

I have a '95 Land Yacht LE that just had the Banks system installed....night & day in operation! She's faster now, quicker on takeoff, doesn't know my car hauler & MGB are hooked to her & gas mileage seems to have increased (only took 1 short trip with her since "Bank-ing her" & appeared to get better mileage)...
...we're heading out Wednesday am for the Gulf Coast, a trip of about 400 miles...I expect to cover the distance with about half a tank of gas (fingers crossed!).....will let you know the gas particulars in a week.....
...but, I can already tell you: power drastically improved, low end torque outstanding!

Tripp · 03-17-2003, 01:27 PM

Ah, the quest for power. . .

It all boils down to cost vs. how much power you want. A free flowing exhaust and intake system is the best bank for the buck. The Banks kit is expensive, but one very positive point is the thickness of the mounting flange for the headers. You want as thick as possible to ensure good sealing with minimal warpage once up to full temperature. Going up those long hills will make your headers glow red (literally). It doesn't take too many trips up those hills to destroy an inferior set of headers.

If you're a big speed junkie (like me) and have a little extra cash, you might consider a supercharger. Very good hp/torque output with no added heat (like a supercharger) under the hood.

I like the over/underdrive units too. Never tried them, but make sense.

Good luck!

Tripp

scotta · 03-17-2003, 07:17 PM

WOW ! You have all been very helpful. After reading all the replies I am thinking I need to find a good "speed junkie"mechanic that can advise me on the most cost effective alternatives. I was leaning towards the Banks system but it sounds like I might be able to go with a less expensive "cat back "system and have money left to spend on other performance boosting components. Thank you all for the helpful advice.

davidz71 · 03-17-2003, 08:03 PM

The Banks system works on freeing restrictions on the intake side as well as the exhaust side. While buying the catback is a step in the right direction, Banks has systems for both ends in a package.

fangthorpe · 03-17-2003, 10:00 PM

I don't know who will be (or is) the brave soul to do this on a motorhome, but I went down the "more power" road with Suburbans pulling a 9000# 24' racecar trailer in California and Colorado, and after several variations (75 454, 88 454, 92 350, 96 350, and 01 5.3) and trying everything you can name (I vintage race and have left over speed parts everywhere), the strongest puller I have owned is the '01 small block 5.3 with a Whipple supercharger and a 4.10 diff. I still have the 88 454 with Edelbrock intake and TPI, big headers and ignition (which is probably what a good tuner would do to a 78-88 gas Airstream motorhome) and the 5.3 is still stronger. I'd guesstimate 365-375 hp and 470 lb/# minimum. And 10 mpg towing and 17 mpg light. Obviously no one has a 5.3 in their big rig, but if the Whipple, with no other modifications at all...no big exhaust, no ignition, nothing...will do this to a 5.3, it seems to me that an 8.1 with a Whipple would be a gentle monster worth owning. Will the Whipple stay on full boost (6 #) for a long time without roasting the motor? I don't know, but my experience towing 30k miles with the 5.3 at around 15,000# gross is that you rarely use the whole pedal and generally are at a much smaller throttle opening than unboosted. I never see 220 degrees of water, even in the mountains in the summer, and it runs at 180, no matter what, unless you're climbing. Somebody with a newer Land Yacht (don't they all have the Vortec 8.1?) should call Whipple and ask. They are very cool folks to deal with and will spend as much time with you as you want (as they should at $3500-4000 per setup) but their quality, design, and manuals are excellent. I firmly believe that if it's a dumb idea for some reason, they would tell you straight away. And as a bonus, the Whipple comes off in a few hours and you can take it with you for your next rig. My problem (see previous posts) is that I probably will end up with an 81-88 Classic with a carburated 454/ 3 speed. I don't know if the Whipple is such a remarkable performer without the computer/FI to fiddle with. Is it a better idea to convert to a newer gas engine and OD trans or to stick a diesel in there and get it over with? We'll see this summer.

davidz71 · 03-17-2003, 10:30 PM

The Whipple supercharger is one heck of a performer. A number of guys have put them in trucks on pickuptrucksforum.com to increase performance of the 5.3 like you did and to put "seat of your pants" performance to the 6 litre Chevy engine. Man O Man would I like to put one on my 8.1 2500hd but $4000 is a tough pill to swallow. I saw one on ebay not long ago that was going for $2500 but don't know what the final bid price was.

fangthorpe · 03-17-2003, 11:26 PM

You just wrote your own rationalization....when you're done, you put it on ebay and get a lot of your money back. How much do you suppose you'd get back from your $2500 for a used Banks system? Call the boat racers to buy. They give a much better deal than the truck guys because they buy/sell so many of them. In fact, they might know about the full throttle results...I've heard boat guys actually open the throttle all the way sometimes. And don't buy a used one unless its a dead nuts match for your rig...some of the chip mods and fuel mapping are very specific for each year. I really want to hear from an Airstream owner who put one of these on. They're a real kick.

davidz71 · 03-18-2003, 06:00 AM

Makes sense to me. One of the guys selling a supercharger said that the person buying his vehicle did not want the supercharger i.e. probably wanted to keep the cost down or really didn't understand the purpose of the thing.

Silvertwinkie · 03-18-2003, 12:52 PM

You have to be careful about supercharging, turbocharging, etc. There is somewhat of a science to it as I understand. You must know that not all engines can take the extra pressure of the ram air. In some cases you can do more damage than benifit. I am not saying this is the case here, but be careful adding components to an engine that were never designed for it.

Case in point was back in the 80s w/ GM diesels. The 350 blocks were not up to the compression and as such, cracked. Not really and apples to apples comparison, but you get the drift......

Regards,

Eric

59toaster · 03-18-2003, 01:23 PM

That's true with Turbo's. It has to work in conjunction with the compresion ratio. The more boost the lower the compression ratio needs to be. If you don't do it that way then you start have detontation problems and blow holes through pistons.
I play (or as soon as it sells did play) with Surpa's These folks pulling 500hp out ot of 3liter engine are often as low a 6.5:1 compression ratio. A run of the mill small block chevy is 8:1. I know people on race gas that can put down 652hp to the rear wheels but on super unleaded they have to tune down to about 475hp to keep from getting detonation and granading the engine.
The difference with a super charger is no lag. You always have some boost at all time. The problem is you have some loss because you have to drive the super charger. The higher the boost the more drag on the engine. So 4psi may equate to the same rear Wheel HP as 6 psi because of the extra effort it takes to drive the super charger.
A turbo charger scavanges it drive off the exhaust. But you have to get the exhaust moving to spin the compressor fast enough to make positive pressure so you get the turbo lag till the enigne gets about 1500rpm. Then when you let off the gas the waste gate opens and your back to square one till the impeller can get back up to speed

Silvertwinkie · 03-18-2003, 03:37 PM

Not to sound ignorant here, but doesn't lowering the compression ratio take a bit of work? I was under the impression that you'd need to change the pistons, the heads or both.

Seems like an awful lot to consider.

Eric

davidz71 · 03-18-2003, 08:08 PM

Some individuals have found out the hard way with their thinking that if a little boost with the supercharger is good then more would make it even better. That is sorta like doing a ph, nitrogen, potassium and potash test of your garden soil, finding it a little low, adding some fertilizer, testing again and deciding that a little extra couldn't hurt. Some vegetables can't handle the high nitrogen, will grow an enormous amount of leaves but produce no vegetables at all. What am I saying here? Just don't overdo the supercharger boost and you will be fine.

Silvertwinkie · 03-18-2003, 09:43 PM

Craig,

Although I agree with the essence of your comments, I am still uncertain that adding a turbo or supercharger even in moderation in this situation is the best suggestion. If you tone it back you are just defeating the purpose of the main HP and torque gain.

The 454 is a hell of a motor, but in all honesty, I know of only a handful of folks that install turbos and superchargers. I know the "new" GM mantra is to add superchargers and call it an SS, but most of the real car nuts simply do the work. They mod the cam, modify the tuning, exhaust, headers, intake, heads, etc. There are few shortcuts when it comes to doing it right. Doing these mods, the HP and torque gains would be significant and he wouldn't have to worry about blowing the intake manifold to hell or blow out a gasket or put a hole in his piston.

I am sure that it's possible to add a supercharger or turbo to any engine. I guess I'm just too old school to buy into adding a turbo to a 454 when in fact that engine can get more power in more traditional ways with less overhead in the engine bay. Adding a bit of turbo is like being half pregnant IMHO. If you want the power, you gotta pay and do the work.

Regards,

Eric

74Argosy24MH · 03-19-2003, 07:28 AM

A turbo moves a lot of heat high up on the engine. They already are mounted fairly high into the passenger area and sealing is marginal. Cooling air flow is not great, it jams into a large box filled by the engine. Turbochargers and superchargers both need large diameter free flowing tube. There is very little space under the engine cover. I added a low/medium rise manifold and 4" air cleaner and had to raise the engine cover 2" at the rear.
These are heavy vehicles and will slow down on big hills. Engine control system changes will be the cheapest because they are easiest.

John