Why Cars with Lots of Mods go Slow, Injectors/AFC, Misc

Some Misc ramblings... Gonna be long..

First.. For those who find it useful, here's what I remember from back when
I installed my 16G...

When I installed it, I had the following mods: full 3" exhaust, upper I/C,
1G BOV, air filter, in-tank fuel pump upgrade, front-mount I/C, boost
controller, and an EGT.  Other than the front mount, this is probably
similar to where many of you were at when you put your 16G on.

I don't know if the front mount would raise or lower EGT's, but what I do
know is that once we put the 16G on, I could not keep the EGT's low enough.
 The setup was worthless to me until I upgraded the injectors and got an
AFC..  That was one of the first of many late-nighters I owe to RRE- we got
back after seeing the nasty EGT's and slapped in an AFC and injectors.  I
bit the bullet and threw it on the credit card.  My rationale is this:
Look, if you are gonna buy something sooner or later, buy it sooner!  Then
you get all the extra enjoyment of having that item for a longer period of
time.  You're just gonna buy it eventually anyways.  Within reason, of
course.. If it's so expensive that you can't pay it off in 6+ months then I
guess interest would become an issue.  But I digress..

With 550's and AFC, the car pulled stronger and the EGT's were *closer* to
where I wanted them to be, but, I was hitting fuel cut unfortunately so I
couldn't use the AFC as I wanted to (I wanted to richen things up in the
higher RPM's but that caused the cut).  So I went to 720's instead of
550's.  This was one way of solving the problem.  Now I had to lean the AFC
settings out more to compensate for the bigger injectors, and fuel cut was
no longer an issue.  Problem solved.  The problem was later re-solved
another way, which was to get a TMO ECU upgrade that eliminates fuel cut.
I recommend it to everyone who has an ECU that will support it.  If not,
there's always 720's.  One or the other will work for everyone.

With no other mods I started running high 12's in poor conditions (muddy
day at Carlsbad).  Then at Pomona I was at mid 12's.  100 octane unleaded
when I raced, pump gas otherwise.  Never touched the leaded stuff.  Cams
and 118 dropped me to 12.1's, arguably even faster than that since towards
the end we installed too aggressive of a clutch and I couldn't launch
anywhere near as well as I did at 12.4/12.5.

Oh yeah.. On the street I ran 19-20+ psi on pump gas, no problems.  Maybe
even a bit more.  When I recently upgraded boost gauges, I found that I had
to turn down the PRofec to get to "20 psi" on the street with the new and
supposedly more accurate gauge.  I suppose I coulda been running 22+ before
then.  BUT of course I do not recommend this, it just happened to work well
on my setup as far as I know!  Do as I say, not as I do :).  Who knows the
condition of my engine now?

Moral of this story?  1) the importance of the AFC and injectors.  That was
the turning point for me hitting 12's and having a car that ran 'safely'
re: EGT's.  2) Regarding the talk about spending all the money & not going
much faster.. You guys are close to having a great combo.. You're at the
brink but you're going to need to go a little further to really reap the
rewards.  Don't stop right as you've spent 90% of the money you need to
spend to get there..

Additional advice: Those w/ 16G's who aren't running fast need to really
look hard at the combination that's on your car.  There are guys with 1G's,
stock turbos, and very few mods in the mid 13's (John M & Scott T).  And
there are several of us both on and off the list who ran high, mid, and low
12's all on the 16G without too many more mods.  EVERY part choice you make
counts!  Are you running a cat?  (How about you Steve H?).  If so, you
could be killing your performance and causing mass backpressure.  If you
aren't sure you believe this, try running with it and without it on the
track and see if there's a difference.  Do you have a good performance
downpipe?  Are you sure your BOV is set up correctly and won't bleed boost
off?  Or that the BOV isn't too tight and not blowing air off enough?  Do
you have a free flowing cat-back exhaust, preferably 3"?  What kind of
boost controller are you using, a bleeder or one which keeps the wastegate
truly 100% shut until close to max boost?  If a plain bleeder, you've
potentially lost a tenth or two (or more?) as well as a feeling of
responsiveness from your turbo.  And let's not even get started about how
you drive at the track!  I remember giving JR a pointer on shifting and the
next run he dropped 2 or 3 tenths off, and woulda dropped even more if his
tranny wasn't giving him fits.  This is an even tougher job for you
FWD'ers, I do not envy you at all!

If you've bought a lot of parts, the things I just mentioned are very
important.  Taking the time to go through your combo and purge yourself of
weak links is the difference between the 14 second cars and the mid 13 and
faster crowd.  I'm trying not to sound like I'm harping, but I probably
invested the same or less than many of you, but by going slow and making
sure I had the right combo I reaped a lot of rewards.  It's no co-incidence
that Billy and I ended up with similar times and a very similar mod list.
We found the parts that worked.

Ok, one more piece of advice for those at the 16G level.. There ARE mods
left to you which cost less than some of your more expensive mods to date
and which will help a lot.  Proven: cam upgrades.  A good grind will not
only give you more power, you'll be amazed to see your EGT's drop by some
30+ degrees Celsius.  And they give you a more "consistent" feel of power
when driving around on the street or freeway.  I can't testify for 1G'ers,
and I DO NOT know if a cam setup has really been proven for the average 1G
car.  But for 2g'ers, get the grind I got from Ronnie, through either RRE
or Ronnie.  (Mine is different than Billy's- all the power with a pretty
darn good idle.  Billy's = all the power + a wicked idle.  Take your pick).

For those who think they should be faster than they're currently running
given their mods, maybe you should post the ENTIRE list of mods on your car
for some of us to comment on.  Make it to the point so it's easy to read
and respond to.  Just the facts.  Don't forget year & model & the brands of
the parts.  Ie:

95 AWD
K&N FIPK
RRE Upper I/C
35G SuperZ Disco Turbo

Hope all this helps someone.

G'nite,
Marc

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