Worth reremong UP TO DATE smog on 454 motorhome ?

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Would it be worth removing the current ( up to date) smog on a crate 454 motorhome?

Would i gain slight fuel economy ? Or power?

We have plans to pull a 6klb boat/ trailer once in a while.
 
Whoops.... Most important part of question.

1982.

So i have the air pump,egr charcoal canister. And whatever else i can't remember @ the moment.
 
Originally Posted By: leroyd92
Whoops.... Most important part of question.

1982.

So i have the air pump, egr, charcoal canister. And whatever else i can't remember @ the moment.


None of these really hurt your power. EGR actually helps with part throttle fuel economy.
 
If the air pump is not working properly then the oxygen sensor in the exhaust will see the wrong information and the engine will not run properly. Do not remove the air pump. If you do you will mess up the way the engine runs.

My 1985 Olds 88 has an air pump. The pipe to one of the exhaust sides rusted out and was leaking the pumped air out before it got to the exhaust. The oxygen sensor was seeing the wrong information and the engine would not idle properly. Fixed the pipe between the air pump and the exhaust and the engine now runs and idles properly.
 
Originally Posted By: leroyd92
Would it be worth removing the current ( up to date) smog on a crate 454 motorhome?

Would i gain slight fuel economy ? Or power?

We have plans to pull a 6klb boat/ trailer once in a while.

I would not do it personally. Messing with smog equipment is a federal beef, and big vehicles like that get more scrutiny than passenger cars.

IOW, the juice isn't worth the squeeze.
 
I don't think the heavy duty 454's in 1982 had any electronics... the small blocks had "ESC" (elec spark control) but I don't recall seeing any '82 big blocks with it.
 
There's no sensors nor computers...

I personally don't wanna mess with it. But if there's mountains to gain id be open to the idea
 
Originally Posted By: leroyd92
There's no sensors nor computers...

I personally don't wanna mess with it. But if there's mountains to gain id be open to the idea


Many of those engines were down on power, not because of the bolted on emission controls, but because of the internal design. Cam timing, valve lift, and duration were all extremely conservative. The compression ratio was also very low. In addition, the valve sizes and port sizes conspire to limit output.

However, if you have one of the old style catalytic converters on it, and small, single exhaust/muffler, they are quite restrictive.

For a while, owners of these were installing free flowing exhausts and the aftermarket throttle body fuel injection systems. That did help the power and MPG, plus eliminated the hot start issues some of them had.

EDIT: Those in the know, replaced those engines with the marine versions that produced 400HP stock.
 
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Originally Posted By: JimPghPA
If the air pump is not working properly then the oxygen sensor in the exhaust will see the wrong information and the engine will not run properly. Do not remove the air pump. If you do you will mess up the way the engine runs.

My 1985 Olds 88 has an air pump. The pipe to one of the exhaust sides rusted out and was leaking the pumped air out before it got to the exhaust. The oxygen sensor was seeing the wrong information and the engine would not idle properly. Fixed the pipe between the air pump and the exhaust and the engine now runs and idles properly.


A.I.R only pumps air into the exhaust during "Open Loop" operation, With an old system like yours with a non-heated O2 sensor was any time the engine is cold or idling.....This is also why the system has Diverter Valve/s to divert the air away from the manifold.
 
Originally Posted By: leroyd92
There's no sensors nor computers...

I personally don't wanna mess with it. But if there's mountains to gain id be open to the idea


You answered your own question!
However if you really wanted to do some tuning.....There is probably alot on the table for that engine even if it's a low compression variant. It's just a ton of work on a carbureted engine.

If it was mine, I would.......
Rip all the A.I.R system off & plug the ports on the manifolds, It creates exhaust heat & that is the last thing you need!
Dual 2 1/2" pipes into Flowmaster Big Block II mufflers, Have a O2 bung welded on each side as close to the manifolds as possible with plugs.
Buy a Wide Band Sensor & monitor (Probably lost you right there because the price)
I would plug the EGR because it will plug itself eventually.....Then you have way to much timing!

Re-Curve your distributor! This is where the most gains come from!
On this engine without EGR.....34-36 degrees total mechanical all in by 2500-2800. Plus 10 degrees vacuum advance hooked to Manifold Vacuum, You will need to limit your existing vacuum advance or buy a adjustable one.
I don't worry much about initial timing as long as the starter don't kick on hot re-starts....I like around 10-12 degrees.

Then use the Wide Band to "Jet" the carburetor (Jets & Metering Rods on a Q-Jet) to achieve as close to 14.7:1 AFR during cruise situations as you can, WOT & High Load will be richer because the accelerator pump & Secondary enrichment circuit.

You will probably need to set/adjust the Secondary Air Valve opening rate which can be tedious....But will eliminate the BOG associated with most Q-Jet carburetors.
 
Exactly which crate engine is this?

Wide variety of 454 from mild to wild.
 
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I don't know what motor it is. it was rebuilt 30k miles ago. Even with the current emissions stuff on it the previous owner said (it hauls butt up mountains)

Valve covers say (gm goodwrench remanufactured)

If i found a number on the block would that tell me what it is?

Id have no issue putting headers on it and removing the 3 ft long mufflers that are on it. It is actually dual exhaust.
 
Originally Posted By: DoubleWasp
I'd have a set of long tubes on that thing by yesterday. That's what's really going to open things up.


I don't know man.....I have never seen headers work out well in a heavy duty application, Sure 3/8" flanges, ARP Bolts, & Steel MLS gaskets will go a long way. But the radiant heat they will put off climbing grades especially towing will be a substantial increase over cast manifolds.
 
Originally Posted By: DoubleWasp
I'd have a set of long tubes on that thing by yesterday. That's what's really going to open things up.


Can you explain what you mean by long tubes? Headers? straight free flowing exhaust?

I think i miss understood you
 
Originally Posted By: clinebarger
Originally Posted By: DoubleWasp
I'd have a set of long tubes on that thing by yesterday. That's what's really going to open things up.


I don't know man.....I have never seen headers work out well in a heavy duty application, Sure 3/8" flanges, ARP Bolts, & Steel MLS gaskets will go a long way. But the radiant heat they will put off climbing grades especially towing will be a substantial increase over cast manifolds.


Wouldn't sweat it. We used to have a customer who had an old Winnebago and an Airstream equipped with long tube headers. Those sets were from the 90's at the latest.

If it really were to be an issue, it's nothing a wrap of DEI Titanium would not take care of. As long as the longtubes were stainless, they'd never rust as a result of moisture.

Besides, how much worse could it be that an old catalyst equipped exhaust? Those things were tested to put up EGT's of 1700-1900 degrees in the manifolds. A free flowing set of long tubes isn't going to put up EGT's nearly that hot.
 
Originally Posted By: leroyd92
Originally Posted By: DoubleWasp
I'd have a set of long tubes on that thing by yesterday. That's what's really going to open things up.


Can you explain what you mean by long tubes? Headers? straight free flowing exhaust?

I think i miss understood you


Yup. Long tube headers. Going to make the powerband fatter and definitely put up the horsepower.
 
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