GMC Open discussion of Upgrades

M

marcus mcgee

New member
Sep 29, 1997
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Ok here goes a very open question. I have two Transmodes that I am
going to rehab for work. I have already done one over the last two
years, but now it is time to get serious with the two "new" ones.

One is a 455 and the other is a 403. Both have low miles - 455 with
25,000 and the 403 with 10,000. I have a working budget of $25,000 for
the upgrades to both. These GMC's will be driven by employess who are
not as crazy as I am and need to be reliable any easy to drive. What
upgrades are the most cost effective and why?

What they must have:

1: Full paint on both - they are both badly chalked $3,500 each $7,000

2: Alcoa wheels and new tires - The tires are old and must be
replaced anyway so I might as well go all the way. $1,900 ea. $3,800

3: Oil cooler lines to radiator $100 each. $ 200
Total $11,000

That leaves $14,000 or $7,000 per coach.

Here are my thoughts:

Full Caspro suspension, Jardine exhaust & headers, upgraded front
calipers & pads. What do you all think and what is the reasoning on the
cost benefit trade off?

I am open for any discussion on all the pros and cons. What about a new
gauges, seats, back up cameras, or any other upgrade you might know of.
Suggestions are greatly appreciated.

Help me develop a working list of upgrades and I will keep everyone
informed on my progress, trials and tribulations.

Thanks
Marcus
 
Marcus:

Can you tell us if your use will be local or long distance driving and
are you talking about the conventional interior amenities usually found
in a normal coach (e. g. bathroom, kitchen, dining and bedroom?

When you say Transmodes, are they currently just a shell or a Royale,
etc?

Paul Bartz
> -----Original Message-----
> From: Marcus McGee [SMTP:crsalert]
> Sent: Tuesday, March 17, 1998 2:35 PM
> To: gmcmotorhome
> Subject: GMC: Re: GMC Open discussion of Upgrades
>
> Ok here goes a very open question. I have two Transmodes that I am
> going to rehab for work. I have already done one over the last two
> years, but now it is time to get serious with the two "new" ones.
>
> One is a 455 and the other is a 403. Both have low miles - 455 with
> 25,000 and the 403 with 10,000. I have a working budget of $25,000 for
> the upgrades to both. These GMC's will be driven by employess who are
> not as crazy as I am and need to be reliable any easy to drive. What
> upgrades are the most cost effective and why?
>
> What they must have:
>
> 1: Full paint on both - they are both badly chalked $3,500 each
> $7,000
>
> 2: Alcoa wheels and new tires - The tires are old and must be
> replaced anyway so I might as well go all the way. $1,900 ea.
> $3,800
>
> 3: Oil cooler lines to radiator $100 each. $
> 200
> Total $11,000
>
> That leaves $14,000 or $7,000 per coach.
>
> Here are my thoughts:
>
> Full Caspro suspension, Jardine exhaust & headers, upgraded front
> calipers & pads. What do you all think and what is the reasoning on
> the cost benefit trade off?
>
> I am open for any discussion on all the pros and cons. What about new
> gauges, seats, back up cameras, or any other upgrade you might know
> of.
>
> Suggestions are greatly appreciated.
>
> Help me develop a working list of upgrades and I will keep everyone
> informed on my progress, trials and tribulations.
>
> Thanks
> Marcus
 
These are open shells, and the interior will have formica on the top
half of the wall and architectural carpet/wall covering on the bottom
half. The ceiling will be a fabric material similar to a auto ceiling
material. The inside will be used as a classroom, training area for
our distributors and also as a sales tool for use at our customers.
We sell lightning warning systems to the golf & recreation market.

They will do a great deal of long haul and then short trips to each
course or demo. We will have no RV amenities other than a coffee maker
and a small 12 volt cooler. The interior will include either a large
screen TV, or an LCD projector and screen for multi media computer
displays. We will seat up to 8 people for demos and 10 in a squeeze.

Basically a traveling office/conference room.
 
Hi Guys,

I think I'd disagree. Headers can make a great improvement, especially
(and I think this is what Marcus alludes to) if the exhaust is designed
properly, i.e. large enough diameter to provide proper flow, proper
muffler, etc.

Jet-Hot coating the headers is a wise investment, as it reduces engine
compartment temps enormously and provides a bullet-proof protective
coating.

Just my .02

Bob Brewer

> In a message dated 98-03-17 15:19:12 EST, you write:
>
> Here are my thoughts:
>
> Full Caspro suspension, Jardine exhaust & headers, upgraded front
> calipers & pads. What do you all think and what is the reasoning on
> the
> cost benefit trade off?
> >>
>
> Marcus
>
> IMHO I would not put on headers. Yes lots of people "LOVE" them.
> Headers are great for hot rods. I have used them on my race cars.
> I would never put on headers in front of a muffler. Headers help to
> get
> more burned fuel and air out of the cylinders. When you have a muffler
> and nearly 20 ft of tail pipe after a header they just cant do that.
> Headers are also going to raise the under hood temps alot. Well I
> have gone and done it now so let me only say that you have my
> honest opinion------maybe not a popular one-----but honest from my
> point of view.
>
> Take Care
> Arch
 
I installed headers, coated (ceramic aluminum) inside and out by High
Performance Coating (http://www.hpcoatings.com), Flowmaster mufflers
(2.5 " inlet/outlet) and 3 " exhaust tubing after the Y-collector.

Not only did that wake up the engine, but I have less heat in the engine
compartment compared to the original system. Thermodynamically, the
hotter the exhaust gasses, the faster they will flow.

Not only is the coating (looks almost chrome plated) an insulator, but
it inhibits corrosion of the piping. I'm not ever expecting to have to
replace the coated piping.

Along with a 3:42 to 1 ring and pinion gear, my 403 ci engine 78 GMC
will outperform a 455 ci engined GMC (without the modifications I
installed) on the hills.

Paul Bartz

> -----Original Message-----
> From: Brewer, Bob [SMTP:rebrewer]
> Sent: Wednesday, March 18, 1998 12:38 AM
> To: 'gmcmotorhome'
> Subject: RE: GMC: Re: GMC Open discussion of Upgrades
>
> I think I'd disagree. Headers can make a great improvement,
> especially (and I think this is what Marcus alludes to) if the exhaust
> is designed properly, i.e. large enough diameter to provide proper
> flow, proper muffler, etc.
>
> Jet-Hot coating the headers is a wise investment, as it reduces engine
> compartment temps enormously and provides a bullet-proof protective
> coating.
>
> Just my .02
>
> Bob Brewer
>
> In a message dated 98-03-17 15:19:12 EST, you write:
>
> Here are my thoughts:
>
> Full Caspro suspension, Jardine exhaust & headers, upgraded front
> calipers & pads. What do you all think and what is the reasoning on
> the cost benefit trade off?
>
> Marcus
>
> IMHO I would not put on headers. Yes lots of people "LOVE" them.
> Headers are great for hot rods. I have used them on my race cars.
>
> I would never put on headers in front of a muffler. Headers help to
> get more burned fuel and air out of the cylinders. When you have a
> muffler and nearly 20 ft of tail pipe after a header they just cant do
> that.
>
> Headers are also going to raise the under hood temps alot.
>
> Well I have gone and done it now so let me only say that you have my
> honest opinion------maybe not a popular one-----but honest from my
> point of view.
>
> Arch
 
>
> I installed headers, coated (ceramic aluminum) inside and out by
> High Performance Coating (http://www.hpcoatings.com), Flowmaster
> mufflers (2.5 " inlet/outlet) and 3 " exhaust tubing after the
> Y-collector.

Paul,

What brand headers did you buy? Just curious, how many miles do you
have on the headers now and how often do you retorque the bolts and
replace header gaskets?

> Along with a 3:42 to 1 ring and pinion gear, my 403 ci engine 78 GMC
> will outperform a 455 ci engined GMC (without the modifications I
> installed) on the hills.

I still suspect the majority of improvement is due to the lower gearing
and less restrictive exhaust system from the manifolds back.

Patrick
- --
Patrick Flowers
Mailto:patri63

The GMC Motorhome Page
http://www.gmcmotorhome.com
 
Paul,

I acheived the same performance you are talking about, but without the
headers. I installed Flowmaster Mufflers, an MSD ignition with a "spark
box" and an open element air cleaner. The engine breathes better and all
the fuel is burnt in the cylinders with the new ignition. An added benefit
with the MSD is the engine now starts much easier.

I have had headers on several other cars and I would not want to install
them on a motorhome. I was replacing header and collector gaskets
continuously on these cars. Due to the nature of headers, they burn gaskets
and I would not want to be replacing them on the GMC too often.

Rich Major
'78 Kingsley

> I installed headers, coated (ceramic aluminum) inside and out by High
> Performance Coating (http://www.hpcoatings.com), Flowmaster mufflers
> (2.5 " inlet/outlet) and 3 " exhaust tubing after the Y-collector.
>
> Not only did that wake up the engine, but I have less heat in the engine
> compartment compared to the original system. Thermodynamically, the
> hotter the exhaust gasses, the faster they will flow.
>
> Not only is the coating (looks almost chrome plated) an insulator, but
> it inhibits corrosion of the piping. I'm not ever expecting to have to
> replace the coated piping.
>
> Along with a 3:42 to 1 ring and pinion gear, my 403 ci engine 78 GMC
> will outperform a 455 ci engined GMC (without the modifications I
> installed) on the hills.
>
> Paul Bartz
>
> > -----Original Message-----
> > From: Brewer, Bob [SMTP:rebrewer]
> > Sent: Wednesday, March 18, 1998 12:38 AM
> > To: 'gmcmotorhome'
> > Subject: RE: GMC: Re: GMC Open discussion of Upgrades
> >
> > I think I'd disagree. Headers can make a great improvement,
> > especially (and I think this is what Marcus alludes to) if the exhaust
> > is designed properly, i.e. large enough diameter to provide proper
> > flow, proper muffler, etc.
> >
> > Jet-Hot coating the headers is a wise investment, as it reduces engine
> > compartment temps enormously and provides a bullet-proof protective
> > coating.
> >
> > Just my .02
> >
> > Bob Brewer
> >
> > In a message dated 98-03-17 15:19:12 EST, you write:
> >
> > Here are my thoughts:
> >
> > Full Caspro suspension, Jardine exhaust & headers, upgraded front
> > calipers & pads. What do you all think and what is the reasoning on
> > the cost benefit trade off?
> >
> > Marcus
> >
> > IMHO I would not put on headers. Yes lots of people "LOVE" them.
> > Headers are great for hot rods. I have used them on my race cars.
> >
> > I would never put on headers in front of a muffler. Headers help to
> > get more burned fuel and air out of the cylinders. When you have a
> > muffler and nearly 20 ft of tail pipe after a header they just cant do
> > that.
> >
> > Headers are also going to raise the under hood temps alot.
> >
> > Well I have gone and done it now so let me only say that you have my
> > honest opinion------maybe not a popular one-----but honest from my
> > point of view.
> >
> > Arch
 
Pat:

The brand is Doug Thorley and I've put about 10,000 miles on them so
far.

Although the Thorley instructions say to retorque the bolts initially,
after a few hours running, after 30 days and every six months
thereafter, I've only retorqued them once.

No problems with the gaskets.

One of the ways to eliminate the leaky/craking original cast iron
exhaust headers common to the GMC, is to change to headers. Everyone
I've heard talk about it says you never have to worry again.

Paul

> -----Original Message-----
> From: Patrick Flowers [SMTP:patri63]
> Sent: Wednesday, March 18, 1998 10:32 AM
> To: gmcmotorhome
> Subject: Re: GMC: Re: GMC Open discussion of Upgrades
>

>
> I installed headers, coated (ceramic aluminum) inside and out by High
> Performance Coating (http://www.hpcoatings.com), Flowmaster mufflers
> (2.5 " inlet/outlet) and 3 " exhaust tubing after the Y-collector.
>
> Paul,
>
> What brand headers did you buy? Just curious, how many miles do you
> have on the headers now and how often do you retorque the bolts and
> replace header gaskets?
>
> Along with a 3:42 to 1 ring and pinion gear, my 403 ci engine 78 GMC
> will outperform a 455 ci engined GMC (without the modifications I
> installed) on the hills.
>
> I still suspect the majority of improvement is due to the lower
> gearing and less restrictive exhaust system from the manifolds back.
>
> Patrick
 
- -----Original Message-----
From: Brewer, Bob
To: 'gmcmotorhome'
Date: Tuesday, March 17, 1998 10:05 PM
Subject: RE: GMC: Re: GMC Open discussion of Upgrades

>Hi Guys,
>
>I think I'd disagree. Headers can make a great improvement, especially
>(and I think this is what Marcus alludes to) if the exhaust is designed
>properly, i.e. large enough diameter to provide proper flow, proper
>muffler, etc.
>
>Jet-Hot coating the headers is a wise investment, as it reduces engine
>compartment temps enormously and provides a bullet-proof protective
>coating.
>
>Just my .02
>
>Bob Brewer
>
>> In a message dated 98-03-17 15:19:12 EST, you write:
>>
>> > Here are my thoughts:
>>
>> Full Caspro suspension, Jardine exhaust & headers, upgraded front
>> calipers & pads. What do you all think and what is the reasoning on
>> the
>> cost benefit trade off?
>> >>
>>
>> Marcus
>>
>> IMHO I would not put on headers. Yes lots of people "LOVE" them.
>> Headers are great for hot rods. I have used them on my race cars.
>> I would never put on headers in front of a muffler. Headers help to
>> get
>> more burned fuel and air out of the cylinders. When you have a muffler
>> and nearly 20 ft of tail pipe after a header they just cant do that.
>> Headers are also going to raise the under hood temps alot. Well I
>> have gone and done it now so let me only say that you have my
>> honest opinion------maybe not a popular one-----but honest from my
>> point of view.
>>
>> Take Care
>> Arch
>Bob..........
I agree with your thoughts on headers. They're designed to do a specific
job, but not for a GMC. Mufflers and a long exhaust system produce back
pressure. Headers are designed to dump exhaust gas rapidly so a clean charge
of fuel can come into the cylinder without exhaust contamination. I just
don't think it can happen on a GMC. We already have an overheating problem
if we're not careful. Why add to it? Jim Davis
>
 
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