buktseat

Does anyone know if MSD or anyone else makes a good capacitive discharge ignition booster for the LS1 truck motor? Or perhaps one for the Fbody/Corvette that I can adapt??

Lostpatrolman

iTrader: (3)

Yes, msd did make a DIS ignition that can be used on the ls1.

buktseat

Can you tell me where to find it - perhaps an internet link to a vendor that has it? Cuz I sure as hell can't find anything except for that Direct Hit thing that interferes with my headers...

jimmyblue

iTrader: (11)

With coil per plug I think you've got all the spark you
need and then some; suggest you check out the
actual performance to be gained (if you can find any
real, unprostituted tests to go by).

But being as it's a truck I bet there is plenty to gain
from tuning spark timing (and compensating for some
of the stuff that's hung on there).

Weigh whatever the "performance ignition" price is,
against HPTuners; "enough" spark at the right time
beats "more than enough" too late. While you're
at it, sell the GMAF and the HPP3 and put your stock
85mm MAF back on. Then you ought to be about
break-even on funds but capability ahead, and no
wild cards in your tune.

buktseat

You had me until the part above. Why would I want to sell anything? Not sure what you're saying there...

jimmyblue

iTrader: (11)

GMAF fakes you lean and gives you spark advance.
HPP3 gives you spark advance. Adding things up
piecemeal is messy and complicates tuning when
you can get to the "*****" directly. Plus the GMAF
is an unknown (but known lean) mixture error to
tune out while the stock MAF is already properly
calibrated and one less thing to waste tuning effort
on.

You can keep them if you want but with the ability
to tune, they both are redundant and meddlesome.

buktseat

I still don't understand what you're talking about. I mean, I hear all the words, and I know what they all mean, but it just doesn't make any sense. Are you saying that the GMAF is crap and that it was a waste of money in the first place and actually causes problems? The thing is allegedly specifically calibrated to work with cold air induction systems. And what "*****"? Who has the ability to tune? I don't... Do you? Real confused, man. Givit to me in straight English...

jimmyblue

iTrader: (11)

GMAF produces less frequency per airflow than stock
units. That's the nut of it. It has several effects due
to how the PCM works.

Less frequency interprets to less sensed mass air flow.
So the PCM shoots less fuel. This makes the mixture lean
(which on the first years of LS-1 (& related iron block)
motors, made more power at WOT because they were
a bit rich as-factory-programmed. Don't know about
your 2000 truck but the 2000 F-bodies were screwed
with a lean tune and small injectors, and they ping
like mad when you hang this kind of thing on there.

Less frequency / sensed mass air flow also results in
less calculated cylinder air charge which is the spark
table index (along with RPM). Spark advance decreases
with more cylAir. So you get more spark advance. More
ping if you aren't lucky, being as you're also leaned out.

Granatelli: "calibrated for cold air induction"
English: "Ping even worse when hot"

Sensed mass air also figures in the more complicated
"load" calculations that the transmission uses to set
main pressure (force motor). So the trans will operate
at reduced holding pressure on the clutches. May slip
or not depending on vehicle weight and engine /
converter torque profile, lots of slip is a tranny killer.

GMAF is not "crap" per se. It's a perfectly good MAF I
expect. But what's "crap" is its calibration (unless you
happen to be naturally over-rich and by just the amount
that Granatelli thinks. Not a likely bet). What's crap
is a company selling this piece as a performance improver
when it causes a whole lot of people a whole lot of grief
by messing up their tune, and then not providing them
any info on how to tune it right. People have asked &
gotten the blow-off, on that one.

***** as in, if you went for the tuning software setup
you can adjust at will the same things that are being
done for (or to) you by these add-ons, but much more
and independently. I tune my car and I've tuned a 5.3
truck as a favor, both using a $499 package that has
both scanning/logging (so you know what's going on)
and editing / flashing (so you can change the tune).
Like the Hypertech did, but about 100X the params.

The trucks have about the same diameter MAF as the
Granatelli and popping the screen is free. The only
power you get is by the false calibration's side effects
and that's a straight crap-shoot if you don't know the
vehicle's natural disposition.

Cheatin' Chad

iTrader: (3)

Add on ignition boxes aren't neccessarily useless just because we have individual coil per cylinder ignition.
There are benefits from multiple spark systems such as increased spark dwell and multiple spark at lower RPM.

This *can* improve idle quality,emissions and gas mileage.

buktseat

Okay Jimmy, NOW you're speakin' my language! Thanks for taking the time to explain all of that. So, that in mind, where and from who does one get their hands on a tuning interface that can do everything the HPP3 can and then some, for only about a hundred bucks more? And let me get this straight, cuz I'm going to try it immediately if I understand you right:

Reinstalling the factory MAF sans the screens and taking out the hypertech tuning is liable to give me more juice? It just doesn't seem possible, ya know - so I gotta make sure I'm hearing you right...

buktseat

Oh and, as it were, what makes the Delphi MAF that you have better than or different from the Stock and/or Granatelli pieces?

jimmyblue

iTrader: (11)

My Delphi MAF is likely the exact same part as came
on your truck. The F-bodies came with a smaller 75mm
and the trucks had 85mm ones. The beauty is that
you can get the MAF calibration table for it, off any
truck guy's PCM (so now it's readily available on the
Internet). GMAF is the same size, but a different
manufacturer, unscreened and with the non-stock
calibration.

So on my car it was a step up in size, that I could
get a true calibration table for, and $40 off eBay.

The key to peak power on any given setup is mixture
and spark timing. You want to know what is up with
that. The trucks have a very low spark advance and
both of these pieces (HPP3 and GMAF) probably push
you in the right direction, sparkwise; but have they
gone all the way? Over the top? Same with the GMAF
mixture effect; want to get your WOT mixture just
right. And full-fledged tuning software lets you set
every param separately - not drift a bunch of 'em at
once by feeding shaved data to the computer. Or
put 6 degrees advance across the board when you
could have used 9 up top but 5 makes midband ping.
That kind of deal.

Going back to the stocker might make you feel like
you lost some power. This can be an illusion or true
depending on what the GMAF did and what the truck
tune was like. The GMAF low- and mid-range mixture
effects are cancelled out by the closed loop fuel trim,
leaving just the extra advance; this would go back
to normal with the stock MAF. But the GMAF trims
may also be adding excess and variable WOT
enrichment. The "seat of the pants" improvement in
street driving (from advance) may or may not be
accompanied by real WOT performance improvement
if the fuel trimming from down low is pushing WOT
mixture right back to where you started.

HPTuners is the $499 software that does logging and
editing both, with a reasonable lock policy (you can
tune your truck and any other '00 5.3 truck). You do
need a laptop. Which may or may not be already in
hand.

LS1-Edit has reduced their price (at least temporarily)
and is attempting to add a logger feature to keep up;
EFILive is working on their own editor and upgraded
cable to complement their scanner tool. It's getting to be
a good time to be tuning, again.

hptuners.com
carputing.com
efilive.com

buktseat

Excellent. Hey listen man - thanks for all the info. I appreciate you taking the time!