350 Magnum EFI (TBI) Performance Improvements
 

I'm wondering what are good price/performance modifications for this motor
(1997, in an inboard ski boat). Specifically, what modifications that would
commonly find on street of off road vehicles, such as heads, cam, MPFI kit,
intake manifold, supercharger, etc, would not work or not work well on a
marine engine application? Obviously exhaust is one of them.

Secondly, how will the existing fuel system cope with additional horsepower,
or is an aftermarket open loop MPFI system one of the required
modifications?

The boat has enough low end for my purposes, so I'd like to bump the power
range to 2000-6000rpm and get another 5-10MPH (70-100 hp?) out of the boat.
(Let's assume it is or will be prop'ed appropriately)

My background is in street and off-road, so any marine application advice is
appreciated.

Thanks in advance.

350 Magnum EFI (TBI) Performance Improvements
 

Buy, borrow, or steal the book "Small Block Chevy Marine Performance" by the
GOD of GM marine engines Dennis Moore.
Read it cover to cover and it will answer all your questions.
Amazon, eBay, or www.mooreperformance.org
Dennis has forgotten more than anyone else will ever know about GM based
marine engines.

"no one" wrote in message
...
I'm wondering what are good price/performance modifications for this motor
(1997, in an inboard ski boat). Specifically, what modifications that
would
commonly find on street of off road vehicles, such as heads, cam, MPFI
kit,
intake manifold, supercharger, etc, would not work or not work well on a
marine engine application? Obviously exhaust is one of them.

Secondly, how will the existing fuel system cope with additional
horsepower,
or is an aftermarket open loop MPFI system one of the required
modifications?

The boat has enough low end for my purposes, so I'd like to bump the power
range to 2000-6000rpm and get another 5-10MPH (70-100 hp?) out of the
boat.
(Let's assume it is or will be prop'ed appropriately)

My background is in street and off-road, so any marine application advice
is
appreciated.

Thanks in advance.

350 Magnum EFI (TBI) Performance Improvements
 

If I recall correctly, the '97 was pre-vortec (at least the marine engines).
If so, you definitely want vortec for hole shot.
Dave

"bomar" wrote in message
...
Buy, borrow, or steal the book "Small Block Chevy Marine Performance" by
the
GOD of GM marine engines Dennis Moore.
Read it cover to cover and it will answer all your questions.
Amazon, eBay, or www.mooreperformance.org
Dennis has forgotten more than anyone else will ever know about GM based
marine engines.

"no one" wrote in message
...
I'm wondering what are good price/performance modifications for this
motor
(1997, in an inboard ski boat). Specifically, what modifications that
would
commonly find on street of off road vehicles, such as heads, cam, MPFI
kit,
intake manifold, supercharger, etc, would not work or not work well on a
marine engine application? Obviously exhaust is one of them.

Secondly, how will the existing fuel system cope with additional
horsepower,
or is an aftermarket open loop MPFI system one of the required
modifications?

The boat has enough low end for my purposes, so I'd like to bump the
power
range to 2000-6000rpm and get another 5-10MPH (70-100 hp?) out of the
boat.
(Let's assume it is or will be prop'ed appropriately)

My background is in street and off-road, so any marine application
advice
is
appreciated.

Thanks in advance.

350 Magnum EFI (TBI) Performance Improvements
 

I called summit, they didn't stock anything called vortec...

Vortec is a word GM used to describe a swirling of the intake gasses in the
cylinder and combustion chamber - what specifically are you talking about?

"Dave" wrote in message
. com...
If I recall correctly, the '97 was pre-vortec (at least the marine
engines).
If so, you definitely want vortec for hole shot.
Dave

"bomar" wrote in message
...
Buy, borrow, or steal the book "Small Block Chevy Marine Performance" by
the
GOD of GM marine engines Dennis Moore.
Read it cover to cover and it will answer all your questions.
Amazon, eBay, or www.mooreperformance.org
Dennis has forgotten more than anyone else will ever know about GM based
marine engines.

"no one" wrote in message
...
I'm wondering what are good price/performance modifications for this
motor
(1997, in an inboard ski boat). Specifically, what modifications that
would
commonly find on street of off road vehicles, such as heads, cam, MPFI
kit,
intake manifold, supercharger, etc, would not work or not work well on
a
marine engine application? Obviously exhaust is one of them.

Secondly, how will the existing fuel system cope with additional
horsepower,
or is an aftermarket open loop MPFI system one of the required
modifications?

The boat has enough low end for my purposes, so I'd like to bump the
power
range to 2000-6000rpm and get another 5-10MPH (70-100 hp?) out of the
boat.
(Let's assume it is or will be prop'ed appropriately)

My background is in street and off-road, so any marine application
advice
is
appreciated.

Thanks in advance.

350 Magnum EFI (TBI) Performance Improvements
 

On Tue, 27 Jan 2004 18:30:58 -0800, "no one"
wrote:

I called summit, they didn't stock anything called vortec...

Vortec is a word GM used to describe a swirling of the intake gasses in the
cylinder and combustion chamber - what specifically are you talking about?
The name "Vortec" originated in the 1986 4.3L V-6 engine that used
"vortex technology" to create a vortex inside the combustion chamber.
GM Powertrain engineers incorporated this phenomenon into their
engines to achieve a better air-to-fuel mixture in the combustion
process. The result is what has now developed into Vortec engines --
engines that are designed to deliver plenty of horsepower without
sacrificing fuel efficiency. While the technology has evolved over
time, the design philosophy remains the same. Vortec engines deliver
both power and efficiency, all in a low-maintenance, durable package.

350 Magnum EFI (TBI) Performance Improvements
 

Yes, you found the website too. I'm looking for good price performance
mods, not a marketing term.

Anyway, I found out some interesting stuff about MPFI from edlebrock I
should share.

Well, the local FI expert at edlebrock seems to think that since marine
manifolds have dry areas, it's completely feasible (and has been done to
extrodinary success) to place aftermarket MPFI systems on marine engines in
a closed loop configuration - you simply sleeve the waterjacket with a
larger hole down to the manifold itself and drill/tap a smaller hole for the
sensor. An absolutely brilliant solution - Having a sensor looking at only
one side of the motor is a compromise, but only a liability if it's out of
tune in the first place, in which case the sensor's not gonna work or last
in anycase.

Now I got a lot of flak a couple months ago about using O2 sensors in marine
applications ( a statement was made that O2 sensors are only valuable for
emissions and catalyst health - which I personally do not agree with but am
not in a position to argue)

Comments on closed loop aftermarket MPFI marine applications???

"Tom Ruta" wrote in message
...
On Tue, 27 Jan 2004 18:30:58 -0800, "no one"
wrote:

I called summit, they didn't stock anything called vortec...

Vortec is a word GM used to describe a swirling of the intake gasses in
the
cylinder and combustion chamber - what specifically are you talking
about?
The name "Vortec" originated in the 1986 4.3L V-6 engine that used
"vortex technology" to create a vortex inside the combustion chamber.
GM Powertrain engineers incorporated this phenomenon into their
engines to achieve a better air-to-fuel mixture in the combustion
process. The result is what has now developed into Vortec engines --
engines that are designed to deliver plenty of horsepower without
sacrificing fuel efficiency. While the technology has evolved over
time, the design philosophy remains the same. Vortec engines deliver
both power and efficiency, all in a low-maintenance, durable package.

350 Magnum EFI (TBI) Performance Improvements
 

On Tue, 27 Jan 2004 18:57:26 -0800, "no one"
wrote:

Yes, you found the website too. I'm looking for good price performance
mods, not a marketing term.


You are crazy to think that adding 10 mph to the top end is (a) wise
or (b) economical. these are semi-displacement hulls and the vast
majority will be squirrely above 50. Maybe with some trim tabs.
Look at Malibu's Corvette for instance.

....
Now I got a lot of flak a couple months ago about using O2 sensors in marine
applications ( a statement was made that O2 sensors are only valuable for
emissions and catalyst health - which I personally do not agree with but am
not in a position to argue)


There are marine O2 sensors. Take to the marine speed shops like Dana
or AZ Speed and Marine.

350 Magnum EFI (TBI) Performance Improvements
 

"no one" wrote in message ...
Yes, you found the website too. I'm looking for good price performance
mods, not a marketing term.

The center-bolt cylinder heads on GM V8's have a large wall in the
intake port. It is easily visible with the intake manifold removed.
This wall improved low end torque and emissions but is a huge
restriction at higher RPM's. The new "Vortec" engines have performance
heads without the intake restrictions and a heart shaped combustion
chamber. I don't know if your motor has Vortec heads or not. I'm
pretty sure the Mercruiser Scorpion engines did. These heads are very
affordable and can make a significant performance improvement. Beware
though, the Vortec intake port is slim and tall and doesn't match up
well to intake manifolds not designed for them.


Anyway, I found out some interesting stuff about MPFI from edlebrock I
should share.

Well, the local FI expert at edlebrock seems to think that since marine
manifolds have dry areas, it's completely feasible (and has been done to
extrodinary success) to place aftermarket MPFI systems on marine engines in
a closed loop configuration - you simply sleeve the waterjacket with a
larger hole down to the manifold itself and drill/tap a smaller hole for the
sensor. An absolutely brilliant solution - Having a sensor looking at only
one side of the motor is a compromise, but only a liability if it's out of
tune in the first place, in which case the sensor's not gonna work or last
in anycase.

Now I got a lot of flak a couple months ago about using O2 sensors in marine
applications ( a statement was made that O2 sensors are only valuable for
emissions and catalyst health - which I personally do not agree with but am
not in a position to argue)

Comments on closed loop aftermarket MPFI marine applications???

Why? What purpose would closed-loop serve?? The computer knows how
much air is entering the engine (displacement x RPM x throttle
openning x temp) it can easily be programmed to supply the correct
amount of fuel without post combustion feedback. The feedback is
neccessary only to trim the fuel to improve catalytic converter
effectiveness. I'll admit some racers are experimenting with wide band
02's but I question why they are neccessary.


"Tom Ruta" wrote in message
...
On Tue, 27 Jan 2004 18:30:58 -0800, "no one"
wrote:

I called summit, they didn't stock anything called vortec...

Vortec is a word GM used to describe a swirling of the intake gasses in
the
cylinder and combustion chamber - what specifically are you talking
about?
The name "Vortec" originated in the 1986 4.3L V-6 engine that used
"vortex technology" to create a vortex inside the combustion chamber.
GM Powertrain engineers incorporated this phenomenon into their
engines to achieve a better air-to-fuel mixture in the combustion
process. The result is what has now developed into Vortec engines --
engines that are designed to deliver plenty of horsepower without
sacrificing fuel efficiency. While the technology has evolved over
time, the design philosophy remains the same. Vortec engines deliver
both power and efficiency, all in a low-maintenance, durable package.

350 Magnum EFI (TBI) Performance Improvements
 

"no one" wrote in message ...
Now I got a lot of flak a couple months ago about using O2 sensors in marine
applications ( a statement was made that O2 sensors are only valuable for
emissions and catalyst health - which I personally do not agree with but am
not in a position to argue)

Comments on closed loop aftermarket MPFI marine applications???

You can do aftermarket SEFI, closed loop with O2 and other cool things
too. Costs money and effort, but it does work, and work well.

Vortec heads produce good low speed torque, but aren't suitable for
high-perf applications where more than 300 - 320 HP is needed.

The trouble is you're talking about a ski boat hull, so adding power
doesn't make much sense. If you like watersking AND going fast there
are alot of boats that would make you happier than a center-engine ski
boat. A Ski Boat does not have to be a flat-bottomed 45 mph inboard.

Lifespeed

350 Magnum EFI (TBI) Performance Improvements
 

"no one" wrote in message
...
I'm wondering what are good price/performance modifications for this
motor
(1997, in an inboard ski boat). Specifically, what modifications that
would
commonly find on street of off road vehicles, such as heads, cam, MPFI
kit,
intake manifold, supercharger, etc, would not work or not work well on a
marine engine application? Obviously exhaust is one of them.


What ever you do to it, is never going to justify the expense. Its a Ski
Boat. Their hulls will only go so fast.


Secondly, how will the existing fuel system cope with additional
horsepower,
or is an aftermarket open loop MPFI system one of the required
modifications?


It won't! you are going to be reprogramming computers, and maybe changing
injectors and increasing fuel pressure.


The boat has enough low end for my purposes, so I'd like to bump the
power
range to 2000-6000rpm and get another 5-10MPH (70-100 hp?) out of the
boat.
(Let's assume it is or will be prop'ed appropriately)


100 HP in a ski boat hull is probably not going to gain you 10 mph. Check
out what speeds are run with a 320 HP engine and then a 400 HP engine.
Its only a couple MPH. To gain 100 HP on a SB Chevy, you are going to
have to change the cam, change and/or port the heads, reprogram the
computer, change the exhaust, and change the fuel system. You are
talking thousands of $$$ here, and when you are done, its gonna be a lousy
ski boat.

350 Magnum EFI (TBI) Performance Improvements
 

"bomar" wrote in message
...
Buy, borrow, or steal the book "Small Block Chevy Marine Performance" by
the
GOD of GM marine engines Dennis Moore.
Read it cover to cover and it will answer all your questions.
Amazon, eBay, or www.mooreperformance.org
Dennis has forgotten more than anyone else will ever know about GM based
marine engines.


Dennis is an excellent STOCK Mercruiser mechanic. PERIOD. He is 10 years
behind the times whenit comes to anything high performance.

350 Magnum EFI (TBI) Performance Improvements
 

"no one" wrote in message ...
I called summit, they didn't stock anything called vortec...

Vortec is a word GM used to describe a swirling of the intake gasses in the
cylinder and combustion chamber - what specifically are you talking about?

"Dave" wrote in message
snip

Just in case you are still interested, these heads are on the Summit
website under:

Engines & components/Cylinder heads and accessories/ GM Performance
Vortec Heads

$259 each with valve and springs.


I'll agree with the others it will take a LOT more power to increase
speed 10mph. A buddy of mine wanted his stock 454 powered 24ft Baja to
go faster. Basically he had to double the power to increase top speed
by 12mph.

350 Magnum EFI (TBI) Performance Improvements
 

"David McNally" wrote in message
om...
I'll agree with the others it will take a LOT more power to increase
speed 10mph. A buddy of mine wanted his stock 454 powered 24ft Baja to
go faster. Basically he had to double the power to increase top speed
by 12mph.

You have got it. PLUS onthat Baja, it can be trimmed out of the water.
An inboard can't. Its taking me 200+ more HP to gain 12-15 mph on my
Formula.

350 Magnum EFI (TBI) Performance Improvements
 

"lifespeed" wrote in message
om...
"no one" wrote in message
...
Now I got a lot of flak a couple months ago about using O2 sensors in
marine
applications ( a statement was made that O2 sensors are only valuable
for
emissions and catalyst health - which I personally do not agree with but
am
not in a position to argue)

Comments on closed loop aftermarket MPFI marine applications???

You can do aftermarket SEFI, closed loop with O2 and other cool things
too. Costs money and effort, but it does work, and work well.

What do you mean by "work well"? Is it as good as open loop or measurably
better? Are there noticeable gains in power, torque, startability,
driveability, fuel economy, and/or smoothness? I still maintain that
feedback fuel control exists only to keep a catalyst operating at peak
efficiency. Even closed loop systems go to open loop enriched conditions
under max power situations and/or for the sake of smoothness. I can see
that maybe a closed loop system might be slightly better on gas but if it's
not controlled well then you're playing with fire. Otherwise I think you're
adding complexity for minimal gain. If someone wants to experiment. by all
means go for it - that someone just won't be me.

350 Magnum EFI (TBI) Performance Improvements
 

Geoff, show me the evidence O2 sensors are primarily for cat performance.
If you've ever seen a fi system go into a bad full rich open loop state,
you'll see the cat is REAL efficient. Like white hot efficient.


"Geoff" wrote in message
gy.com...

"lifespeed" wrote in message
om...
"no one" wrote in message
...
Now I got a lot of flak a couple months ago about using O2 sensors in
marine
applications ( a statement was made that O2 sensors are only valuable
for
emissions and catalyst health - which I personally do not agree with
but
am
not in a position to argue)

Comments on closed loop aftermarket MPFI marine applications???

You can do aftermarket SEFI, closed loop with O2 and other cool things
too. Costs money and effort, but it does work, and work well.

What do you mean by "work well"? Is it as good as open loop or measurably
better? Are there noticeable gains in power, torque, startability,
driveability, fuel economy, and/or smoothness? I still maintain that
feedback fuel control exists only to keep a catalyst operating at peak
efficiency. Even closed loop systems go to open loop enriched conditions
under max power situations and/or for the sake of smoothness. I can see
that maybe a closed loop system might be slightly better on gas but if
it's
not controlled well then you're playing with fire. Otherwise I think
you're
adding complexity for minimal gain. If someone wants to experiment. by
all
means go for it - that someone just won't be me.

350 Magnum EFI (TBI) Performance Improvements
 

"Geoff" wrote in message igy.com...
You can do aftermarket SEFI, closed loop with O2 and other cool things
too. Costs money and effort, but it does work, and work well.

What do you mean by "work well"? Is it as good as open loop or measurably
better? Are there noticeable gains in power, torque, startability,
driveability, fuel economy, and/or smoothness? I still maintain that
feedback fuel control exists only to keep a catalyst operating at peak
efficiency. Even closed loop systems go to open loop enriched conditions
under max power situations and/or for the sake of smoothness. I can see
that maybe a closed loop system might be slightly better on gas but if it's
not controlled well then you're playing with fire. Otherwise I think you're
adding complexity for minimal gain. If someone wants to experiment. by all
means go for it - that someone just won't be me.

By work well, I mean improved fuel economy at part throttle for the
ordinary O2 sensors. They don't have a wide enough range to cover
higher throttle settings. It is worth doing. I have such a setup on
a powerful 454 Chevy and the idle quality and fuel economy are very
good considering the high output.

The wideband O2 sensors can go a step further and keep the mixture
"tuned" at WOT also. Haven't tried this yet, but I probably will in
the future. More expensive, I'm waiting for prices to drop.

Yes, you can map your engine open-loop. Obviously, my engine is
mapped open-loop for heavy loads. If you are a knowledgeable engine
tuner you can do a good job. However, it is hard to account for
varying temperatures and air pressures perfectly. Open-loop is
certainly good enough, but it is hard to produce the
perfect-under-all-conditions power and economy that a wideband O2 will
provide.

Lifespeed

350 Magnum EFI (TBI) Performance Improvements
 

"Tom Ruta" wrote in message
...

You are crazy to think that adding 10 mph to the top end is (a) wise
or (b) economical. these are semi-displacement hulls and the vast
majority will be squirrely above 50. Maybe with some trim tabs.
Look at Malibu's Corvette for instance.

I don't think what you call "semi-displacement" hulls are any more dangerous
than other hulls at a given speed.

I've been 82 mph in a blown Malibu, and it was quite stable...in fact, it
felt very secure.

The real issue with hot-rodding a inboard ski boat is the practallity of it.
With the prop fixed facing downward, it will always "push up" the rear of
the boat, resulting in the front going down, resulting in a higher wetted
surface.

This is exactly what high-performance boaters try to minimize...wetted
surface. Maybe that's why my buddies Malibu seemed so "solid"...it had a
good plant in the water, however, that engine would easily break 100 in a
"trimable" hull.

--
It's just about going fast...that's all...

http://home.insight.rr.com/cgreen/

350 Magnum EFI (TBI) Performance Improvements
 

"no one" wrote in message ...
Geoff, show me the evidence O2 sensors are primarily for cat performance.

Here is a training document from Toyota. Read the first line of the
document #37- "oxygen and air/ fuel sensors"

http://smccd.net/accounts/sullivank/

If you've ever seen a fi system go into a bad full rich open loop state,
you'll see the cat is REAL efficient. Like white hot efficient.

The problem is with three way converters. Read document #64 from the
same link it will explain the need for tight fuel control on catalytic
converter equipped engines.

Hope this helps.




"Geoff" wrote in message
gy.com...

"lifespeed" wrote in message
om...
"no one" wrote in message
...
Now I got a lot of flak a couple months ago about using O2 sensors in
marine
applications ( a statement was made that O2 sensors are only valuable
for
emissions and catalyst health - which I personally do not agree with
but
am
not in a position to argue)

Comments on closed loop aftermarket MPFI marine applications???

You can do aftermarket SEFI, closed loop with O2 and other cool things
too. Costs money and effort, but it does work, and work well.

What do you mean by "work well"? Is it as good as open loop or measurably
better? Are there noticeable gains in power, torque, startability,
driveability, fuel economy, and/or smoothness? I still maintain that
feedback fuel control exists only to keep a catalyst operating at peak
efficiency. Even closed loop systems go to open loop enriched conditions
under max power situations and/or for the sake of smoothness. I can see
that maybe a closed loop system might be slightly better on gas but if
it's
not controlled well then you're playing with fire. Otherwise I think
you're
adding complexity for minimal gain. If someone wants to experiment. by
all
means go for it - that someone just won't be me.

350 Magnum EFI (TBI) Performance Improvements
 

"NetSock" wrote in message ...
I don't think what you call "semi-displacement" hulls are any more dangerous
than other hulls at a given speed.

It might take more than one ride to verify this . . .

I've been 82 mph in a blown Malibu, and it was quite stable...in fact, it
felt very secure.

A nose-down attitude has more implications than just drag. Dynamic
balance and re-entering the water after hitting some chop come to
mind.

Lifespeed

350 Magnum EFI (TBI) Performance Improvements
 

On Fri, 30 Jan 2004 08:02:41 -0500, "NetSock"
wrote:

....
I don't think what you call "semi-displacement" hulls are any more dangerous
than other hulls at a given speed.


Compared to what? A supercharged jon boat? Put me in a V at 60+
please.

I've been 82 mph in a blown Malibu, and it was quite stable...in fact, it
felt very secure.


I'd love to see GPS proof of that.

...
This is exactly what high-performance boaters try to minimize...wetted
surface. Maybe that's why my buddies Malibu seemed so "solid"...it had a
good plant in the water, however, that engine would easily break 100 in a
"trimable" hull.


He should have added a set of Bennett tabs.

350 Magnum EFI (TBI) Performance Improvements
 

"lifespeed" wrote in message
m...
I've been 82 mph in a blown Malibu, and it was quite stable...in fact,
it
felt very secure.

A nose-down attitude has more implications than just drag. Dynamic
balance and re-entering the water after hitting some chop come to
mind.


along with bow steer which is not good at idle speed, and is VERY bad at
high speed. I'd like to see video of a Malibu doing 82 mph. That speed
and that hull/design/evrything do not compute.

350 Magnum EFI (TBI) Performance Improvements
 

"no one" wrote in message
...
Geoff, show me the evidence O2 sensors are primarily for cat performance.
If you've ever seen a fi system go into a bad full rich open loop state,
you'll see the cat is REAL efficient. Like white hot efficient.

Not a conventional three-way catalyst. Once it goes rich and all the stored
oxygen is gone it loads up with carbon really fast and it cools off. In
fact, excess fuel is used to for catalyst protection when it gets too hot.
I didn't read the posted link but hopefully it included little story on the
oxygen-bucket theory. Sometime in the near future (post-Super Bowl) I'll
find the catalyst efficiency vs. lambda charts online and post a link - TWC
efficiency diverges quickly from stoichiometry.

350 Magnum EFI (TBI) Performance Improvements
 

"Tom Ruta" wrote in message
...
On Fri, 30 Jan 2004 08:02:41 -0500, "NetSock"
wrote:

...
I don't think what you call "semi-displacement" hulls are any more
dangerous
than other hulls at a given speed.


Compared to what? A supercharged jon boat? Put me in a V at 60+
please.

Compared to other vees.

I've been 82 mph in a blown Malibu, and it was quite stable...in fact, it
felt very secure.


I'd love to see GPS proof of that.

It was in fact on a GPSR.

Most passes were about 74-78 mph (2 average men aboard), but as fuel
lightened the load, we had one good pass with the wind on glass, of 82.

This is exactly what high-performance boaters try to minimize...wetted
surface. Maybe that's why my buddies Malibu seemed so "solid"...it had a
good plant in the water, however, that engine would easily break 100 in a
"trimable" hull.


He should have added a set of Bennett tabs.

I cant see how tabs can help a fixed-prop inboard. And I'm 90% sure the
Malibu Corvette had a "ride plate"...not adjustable tabs.


--

It's just about going fast...that's all...

http://home.insight.rr.com/cgreen/

350 Magnum EFI (TBI) Performance Improvements
 

On Mon, 2 Feb 2004 08:13:16 -0500, "NetSock"
wrote:
....
It was in fact on a GPSR.

OK.

Most passes were about 74-78 mph (2 average men aboard), but as fuel
lightened the load, we had one good pass with the wind on glass, of 82.


Ah... downhill with the current... got it. 74 is a darn sight away
from 82. And it is interesting that less gas would give a higher
speed since the loss of weight in the rear would drive the nose down.

....
I cant see how tabs can help a fixed-prop inboard. And I'm 90% sure the
Malibu Corvette had a "ride plate"...not adjustable tabs.


Trim tab, "ride plate", Hydrogate, (you work for Tige or Correct Craft
or something? That is marketing speak!), whatever - a moveable plate
at the stern that alters the wetted surface.

350 Magnum EFI (TBI) Performance Improvements
 

"Tom Ruta" wrote in message
...

Ah... downhill with the current... got it. 74 is a darn sight away
from 82.

It was a very large reservoir...no current. And there are many more
variables such as, weight, temperature, chop, wind, humidity, barometer,
etc.

It is not uncommon to have a "spread" of 10% on top end with a blown V8,
throughout the day because of these variables.

And it is interesting that less gas would give a higher
speed since the loss of weight in the rear would drive the nose down.

Apparently not. :)

Trim tab, "ride plate", Hydrogate, (you work for Tige or Correct Craft
or something? That is marketing speak!), whatever - a moveable plate
at the stern that alters the wetted surface.

Tom, the Malibu Corvette does not have a "moveable plate at the stern that
alters the wetted surface".

The ride "plate", is fixed, and does not extend pass the rear of the
transom. The purpose is most likely for strength.

Again, I see no reason (performance gain) for adding adjustable trim tabs to
a fixed prop inboard, other than to compensate for uneven (right to left)
loading.

--

It's just about going fast...that's all...

http://home.insight.rr.com/cgreen/

350 Magnum EFI (TBI) Performance Improvements
 

"Geoff" wrote in message
gy.com...

"no one" wrote in message
...
Not a conventional three-way catalyst. Once it goes rich and all the
stored
oxygen is gone it loads up with carbon really fast and it cools off. In
fact, excess fuel is used to for catalyst protection when it gets too hot.
I didn't read the posted link but hopefully it included little story on
the
oxygen-bucket theory. Sometime in the near future (post-Super Bowl) I'll
find the catalyst efficiency vs. lambda charts online and post a link -
TWC
efficiency diverges quickly from stoichiometry.


I found what I was looking for if anyone is still interested -
http://www.autoshop101.com/forms/h64.pdf, the top of page 4 shows the plots
of HC, CO, and NOx efficiencies versus air-fuel ratio.

350 Magnum EFI (TBI) Performance Improvements
 

"Geoff" wrote in message igy.com...
snip

I found what I was looking for if anyone is still interested -
http://www.autoshop101.com/forms/h64.pdf, the top of page 4 shows the plots
of HC, CO, and NOx efficiencies versus air-fuel ratio.

That is the same document I posted above. Thanks for the more direct
link. Here then is the direct link to the Toyota document for oxygen
sensors.

http://www.autoshop101.com/forms/h37.pdf

The first line is:

"The ECM uses an oxygen sensor to ensure the air/ratio is correct for
the catalytic converter."

I hope the "evidence" is good enough.

350 Magnum EFI (TBI) Performance Improvements
 

"Doug Meredith" wrote in message ...

along with bow steer which is not good at idle speed, and is VERY bad at
high speed. I'd like to see video of a Malibu doing 82 mph. That speed
and that hull/design/evrything do not compute.

Absolutely. I had some mild bow steer at high speeds on my old
Schiada when I let off the throttle too quick (long story, since
fixed) at 85 - 90 mph. It was *not* a good feeling.

Lifespeed

350 Magnum EFI (TBI) Performance Improvements
 

"NetSock" wrote in message ...
Tom, the Malibu Corvette does not have a "moveable plate at the stern that
alters the wetted surface".

The ride "plate", is fixed, and does not extend pass the rear of the
transom. The purpose is most likely for strength.

The purpose is to avoid issues of blasting the gelcoat off the bottom
with propwash. Any powerful V-drive has the keel after the prop
plated with stainless for this reason.

Lifespeed