Valve Train noise

[John Hess]

The curve remains pretty much the same with attendant increases across 
the board (remember, you haven't changed the dominant characteristic 
of where maximum torque will be build, the runner length).  There are 
increases all along the curve that can be felt in the seat of your 
pants.  As for "butchering" your $300 MAF sensor, I would not 
recommend it.  Modify, yes...butcher, no!

As for the bench flow numbers not giving one a rise...Note that any 
improvements in air flow amount to "free" horsepower.  The more air 
one can move with the same amount of energy, the more gas can be 
mixed, thus more power.

Bye the way, I live in central Texas, where it is not at all unusual 
for the temperature to be in the hundreds for days or weeks at a time 
in the summer.  I have been running a modified MAF for 4 years, now, 
along with the modified filter housing, a K&N filter, CB Performance 
56mm throttle body (with air foil), ported plenum and base, SLP 
siamesed runners, Performance Distributor distributor, coil, Live 
Wires and electronics, Air Flow Research heads (2.02 valves, 190cc 
ports), Competition Cams Roller rockers, roller lifters ('89 block), 
Lingenfelter headers,   Random Catalytic converter, and Borla 
Cat-back.  Not all of this was done at once (I started with the K&N 
and Air Foil and modified the intake system piece by piece), so I can 
tell you that each of the changes produced measurable results, more at 
the top end than at the bottom, but that is pretty much to be 
expected.

As for a non-MAF engine producing more horsepower;  yes, it will (one 
less piece of air resistance).  Note that you will also have to remap 
the chip and modify the wiring harness to accomodate the changes, 
though.

----------
From:  George M. Dailey[SMTP:gmd at tecinfo.com]
Sent:  Monday, January 20, 1997 10:32 AM
To:  diy_efi at coulomb.eng.ohio-state.edu
Subject:  RE: Valve Train noise

What do the torque curves look like after doing these mods? Since the 
TPI
system is designed to give the maximum tuned effect at a certian 
point, what
do you really gain?  Bench flow numbers don't give me a rise. Some 
TPI
system don't even use a MAF. Do they have a _significant_ power 
advantage
over the MAF equiped tpi? Convince me to butcher my $300 MAF.

Thanks man
GMD

At 09:25 AM 1/20/97 -0600, you wrote:
>I would rather not quote my source;  however, if one looks at the 
flow
>characteristics of the stock TPI one finds that it flows 
approximately
>435 CFM.  Making slight mods as follows causes significant changes to 
>this.
>Cut the screens off the MAF increases the flow to 512 CFM
>Install a throttle body air foil increases the flow further to about 
>530 CFM (Still not in the realm of what one would consider for even a 
>moderate performance 350).
>Opening up the filter cover and putting a K&N filter in gets us into 
>the 560 CFM range.
>Modifying the MAF (Cutting and polishing the heat sink inside) gets 
us
>up to about 585
>As you can see, there is room for much improvement without ever
>getting out of the air intake.
>
>The MAF, itself flows about 529 CFM stock.  Taking the screens out
>gets it up to over 700 CFM.  Modifying the heat sink and cleaning up 
>the inside gets it up to about 750 CFM.
>
>Note that all this data is corrected to 20.4 inches of water (What
>Holley rates their carburetors at).
>
>Since this is a "dry" flow system (no fuel in the air stream), the
>equivalent to a carbureted engine is about 650 CFM.  NOW we are in 
the
>realm of a solid 350.  Further improvements may now be realized by
>mods to the throttle body, plenum, runners, and base.
>
>
>----------
>From:  Scot Sealander[SMTP:Sealand at clarityconnect.com]
>Sent:  Saturday, January 18, 1997 7:47 PM
>To:  diy_efi at coulomb.eng.ohio-state.edu
>Subject:  Re: Valve Train noise
>
>John Hess wrote:
>
>> The original TPI was designed for the 305 engine
>> and is woefully inadequate for even a mildly built 350.
>
>Do you have a source for this?  How do you know it was designed for
>the 305,
>and not the 350?
>
>
>> To state that these parts are fraudulent or that the people
>> who sell them are liars is irresponsible and/or stupid..
>
>Maybe not.  Just what does that "air foil" do anyway... ;-)  As far 
as
>aftermarket PROMs, the three I have looked at did not do much.  Delay 
>TCC lock
>up by several mph, maybe reduce the ESC attack rate (makes sure of 
the
>need
>for 93 octane!)  Change fan turn on temp.... One completely zero'd
>every EGR
>location..... Basically no ignition or fuel changes.  Not a lot for
>the 150
>bucks or so they charge!  That is close to fraudulent in my book, and 
>points
>out that GM tunes them pretty well from the factory.
>
>I am sure that some of the aftermarket is great stuff, but the
>consumer must
>understand what he is buying.  The TPI is a great low/mid RPM intake 
>system,
>and that may not be clear to all consumers.  So if you make changes 
to
>your
>350 that increase airflow requirements at higher RPMs, the TPI will
>not work
>well for you.
>
>Scot Sealander    Sealand at clarityconnect.com
>
>
>
>
>