oange ss

iTrader: (50)

exhaust is virtually leak free, there's a couple pinhole leaks in the I-pipe,but i think they're far enough down the line to not affect fueling.....i have a wideband

RedHardSupra

iTrader: (1)

click on my sig and go to the '17 tips for any car' and there are examples of header leaks and what they look like in the logs. take a look at your logs and see if they look similar. it doesn't take a big leak to bleed off a lot of compression. think about it as a baloon with a lot of air in it, it doens't take a big hole or a lot of time for the baloon to lose air quickly.

WS6FirebirdTA00

iTrader: (33)

well who on here has dyno numbers and airflow numbers? i think that would be the best way to see.

ozws6

iTrader: (25)

When my TA was stock, the car dynoed 319 rwhp @ 5600 rpm, MAF 35.0 lb/min. With my old setup in the sig, 438 rwhp @ 6300 rpm, 50.4 lb/min MAF.

For my new setup (low compression 402), I'm seeing 58 lb/min @ 6000 rpm (still naturally aspirated, sorting out which turbo kit to go with). Does this mean that I will make 525 rwhp with my new setup? I could only wish!!!! More like 425-450 rwhp since I'm at 8.4:1 for compression (planning to get back on the dyno next month).

WS6FirebirdTA00

iTrader: (33)

what rpm did you get those readings for airflow at?

also was the VE dialed in? was commanded AFR=actual afr? reason i ask is i see a lot of pe tables that correct ve error and a ve table off or maf reading off and corrected by pe will give inconsistent flowrates

ozws6

iTrader: (25)

WS6FirebirdTA00, The MAF readings were at the rwhp max (319 rwhp, 35.0 lbs/min @ 5600: 438 rwhp, 50.4 lbs/min @ 6300 rpm). The stock #'s were with the bone stock tune. The MAF readings for my 346 head/cam combo (438rwhp) were accurate based on AFR. The commanded PE AFR was within .1 to .2 of the actual (varied + and - over the RPM range). I tuned my car with HPTuners by setting the VE table without the MAF, and adjusted the MAF curve so that the commanded PE AFR was as close as possible to actual.

WS6FirebirdTA00

iTrader: (33)

cool man thanks for the info, taking into account 15% drivetrain loss that would make 439 rwhp

WS6FirebirdTA00

iTrader: (33)

btw, what was your compression ratio with the 205 heads?

ozws6

iTrader: (25)

No problem! My compression with the AFR 205cc heads was 11.0:1 (62cc). Those dyno numbers were made back in March 05 and I think I might have already been having problems with cylinder #7 (partially blew the dip stick out of the tube on the dyno). My #7 piston had the ring land broke into 3 pieces accross a 4" section. I only put about 3000 miles on the head/cam combo before the last time I had the car out back in July at the track when it began blowing out the oil dipstick tube along with oil at high rpm. Granted that was a very hard 3000 miles. When I did a compression check after I knew I had problems, 115 psi on #7, 210 psi on the other cylinders!

WS6FirebirdTA00

iTrader: (33)

well i have the same heads and at 6000 rpm i see 45.5lb/hr witha 230/232 cam.

i wonder what kidna variables are in this, one guy had the same airflow as me on his 383 but made 460 rwhp?

ozws6

iTrader: (25)

At 6000 rpm I was seeing 48 lb/min during my dyno pulls. That's about 5% greater than your #'s (45.5). Ironically I did also increase the upper part of my MAF curve about 5% vs. stock when I corrected it for the commanded PE AFR vs. actual AFR. I'm using an SLP descreened MAF.

There are alot of factors that can influence actual hp vs the MAF reading. Things such as dyno to dyno variation, dyno correction factors (colder air temps will give you a higher MAF reading with the SAE corrected hp#s), MAF type and calibration, etc...the list can go on and on.

WS6FirebirdTA00

iTrader: (33)

i need to dyno for my own compairison lol just trying to find someone around here to trust, i think we will be doing it mid march though so we will see

WS6FirebirdTA00

iTrader: (33)

well i got dead on my numbers from using rceng.com fuel calculator. assuming 12% drivetrain loss for 6 speed 10 bolt.

i made 435 rwhp, flow about 45# of air on the street at that rpm and was rich on the dyno compaired to my street runs.

67Firebird455

iTrader: (27)

I'm so confused. I just logged with EfiLive tonight and got 58.10 lb/min and avg cylair of .34, max of 1.73, and that's commanding the AFR to 11.70, what would I be looking at with the 6 speed and 4.10's?

Edit - BTW, that was with a max RPM of 5147.

WS6FirebirdTA00

iTrader: (33)

from what i have seen, max airflow equals max power at crank, or at least that is how it worked for me assuming about 12-15% loss

67Firebird455

iTrader: (27)

That's 493rwhp with 15%, seems a little high... I thought that's what it sounded like, but there are more factors in it I guess... Can an expert chime in and help?

WS6FirebirdTA00

iTrader: (33)

there is no way to get an exact number on this and there are no "experts". the slightest error in fueling tables, ve tables, maf tables ect all play a role in this. you also dont know your drivetrain loss, unless you get on the dyno and do some calculations to back it out. i am sure if you had all this in line it would be a lot more accurate. just dyno the car and see how your car stands, from then on you can get a good idea of power increase for airflow increase

67Firebird455

iTrader: (27)

Very true point my friend... Haven't lost a race yet in this area, so I guess I'm doing okay! =)

WS6FirebirdTA00

iTrader: (33)

haha, i hear ya

Blacker

iTrader: (3)

With my cammed A4, I was pulling 350g/sec at 6,200rpm which is 46.20 lbs/min. Does not seem to bad when comparing to other cars. I plan to dyno the car after installing the LS6 Intake and we see how it compares to actual rwhp.