Zombie

iTrader: (2)

Did some more tuning last night and at 8psi the car feels really fast for such low boost. I noticed the timing (still controled by stock ecu) was only reading 12-14 degrees at WOT so I upped it to 20-23 degrees lol... you might say the difference was noticable. I haven't run a wastegate spring lower than 14 psi for almost 2 years now and haven't had the ability to tune those areas well because of how fast it transitions through them. Boost comes on faster now as well much to the dismay of my tires. I think in our current weather I could crack into the 10s at 8psi.

These kind of results are making me wish I would have gone to SD sooner. I've only got one fuel pump turned on at the moment as well so it's probably just about maxxed out. I need to wire in the hobbs switch for the 2nd pump so it kicks on under boost. I noticed my duty cycle was 55% at 6000 rpms with 96lb/hr injectors so fuel pressure is probably dropping.

cablebandit

iTrader: (37)

its the timing....at that low of boost on a l/c shortblock you can run stock timing almost

Zombie

iTrader: (2)

I know the timing is where the power is coming from, i'm just suprised at how strong it feels on such low boost. I was missing out on part throttle power and faster spooling because I wasn't able to tune these areas like I can now.

Speed density is definately worth it.

cablebandit

iTrader: (37)

oh. now i agree with that...its nice to have the a/f correct for 0-xx boost instead of just 0 OR xx boost

Pro Stock John

iTrader: (34)

Well you also changed the timing, so you would need to say "car feels fast with SD and ~stock timing."


/dr.pedantic

70Stang

iTrader: (2)

I found that it felt 'crisper' with the SD compared to the MAF.

Phil99vette

iTrader: (11)

It feels crisper because the A/F comes in quicker. On a SD car it instantly goes where it needs while a MAF car you can see a 500-1500rpm lag to the right A/F.

Schantin

iTrader: (6)

If you're talking switching to 2 or 3-bar SD, yep I definetly agree. 1-bar I had a big dead area at part throttle and low gear (1st and 2nd) under boost to compensate for the higher loads in higher gears. The 2-bar conversion allowed me to tune "under the curve" for part-boost conditions, and yes, that definetly reduced lag times and made the car "feel" much faster.

Might have to look at the timing on mine.....as I'm running a conservative puss 16 degrees at WOT. I'll be dyno-tuning the car sometime in the next 3-4 months....will post my $0.02 on timing then

hellbents10

iTrader: (10)

SD is where its at.

engineermike

Mine definitely spools up quicker with a 2 bar tune over a MAF tune. The problem with my MAF tune is that I had it tuned very rich when the MAF max'd out, so as the boost went up, it would go through a rich spot before the air would catch up with the fuel flow.

Now, I have it tuned to where the A/F is running around 14.5 at part throttle. You hit the gas, and it goes to 13. As the turbo spools, it goes to 12.5. At full boost, it's around 11.

Mike