b16hybridsol

recently got into a discrepancy with some guys on a local board about this. So I'm simply looking for more opinions.

setup is a stock b16a on pump gas (sc61 i believe)



summary from my side: basically my thoughts are its to lean almost everywhere and the af curve is sloppy.

P.S. the motor burned up cyl #3 (d/b/h series leanest cylinder) while doing 5th gear pulls


the link for those of you who are interested in the full story (3pg read) I am user "h22turboteg"
click me


Modified by b16hybridsol at 11:32 PM 6/13/2006

AbitAvenger

I agree with your statements made in the posts on that forum.

It was def too choppy for me

I'm surprised nobody else saw that

LilCivic04

why would u do fifth gear pulls? i thought that was the gear you should kind of stay away from, since your in boost to long

.RTErnie

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LilCivic04 &raquo;</TD></TR><TR><TD CLASS="quote">why would u do fifth gear pulls? i thought that was the gear you should kind of stay away from, since your in boost to long</TD></TR></TABLE>

thats a myth. with a proper tune you can boost to your hearts content in 5th... with a proper tune.

real choppy afr and i would've been at least .7aft richer than the graph...not to say that the afr has been recently calibrated either...it could be off almost .5 afr in either direction...meaning he easily could've been at 13:1 @ 11 psi.

david@didrace.com

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ~RTErnie~ &raquo;</TD></TR><TR><TD CLASS="quote">
thats a myth. with a proper tune you can boost to your hearts content in 5th... with a proper tune.

real choppy afr and i would've been at least .7aft richer than the graph...not to say that the afr has been recently calibrated either...it could be off almost .5 afr in either direction...meaning he easily could've been at 13:1 @ 11 psi.</TD></TR></TABLE>

Agreed.

PrecisionH23a

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LilCivic04 &raquo;</TD></TR><TR><TD CLASS="quote">why would u do fifth gear pulls? i thought that was the gear you should kind of stay away from, since your in boost to long</TD></TR></TABLE>

By theory, you don't do a lot of 5th gear pulls on the interstate due to drag (wind resistance). Once you are doing 100+mph your engine has to work even harder to overcome air drag. I cannot remember the conversion factor off the top of my head... but I believe the drag force is quadrupled once speed is doubled. It's been a while since I've taken fluid dynamics... all you internet engineers feel free to google up the equations This drag puts increased stress on your engine. So on a dyno this '5th gear factor' doesn't really apply. Of course there are other ways to counter drag as we all know and with a proper tune and precautions you can do 5th gear pulls to your hearts content.

Also, this tune is way too lean. Going into boost he is running way too lean and afterward 6500 it could be cleaned up a bit.

nowtype

Thats choppy? Give me a freaking break. Its only slightly lean in boost. SLIGHTLY. Richening up when full boost hits for sure and a little afterwards and the vehicle would be again, slightly safer. Most will tell you that tuning AFR is not what you should do. Many articles and books will tell you to run 12-13AFR(as thats where optimal burn lies) and then tune the ignition timing from there. We run richer AFRs simply because our engines were never meant for boost and we need a higher margin for error. Honestly, that AFR curve looks damn good except for it being slightly leaner than I'd want when full boost comes.

PrecisionH23a

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nowtype &raquo;</TD></TR><TR><TD CLASS="quote">Thats choppy? Give me a freaking break. Its only slightly lean in boost. SLIGHTLY. Richening up when full boost hits for sure and a little afterwards and the vehicle would be again, slightly safer. Most will tell you that tuning AFR is not what you should do. Many articles and books will tell you to run 12-13AFR(as thats where optimal burn lies) and then tune the ignition timing from there. We run richer AFRs simply because our engines were never meant for boost and we need a higher margin for error. Honestly, that AFR curve looks damn good except for it being slightly leaner than I'd want when full boost comes.</TD></TR></TABLE>

b16hybridsol

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nowtype &raquo;</TD></TR><TR><TD CLASS="quote">Thats choppy? Give me a freaking break. Its only slightly lean in boost. SLIGHTLY. Richening up when full boost hits for sure and a little afterwards and the vehicle would be again, slightly safer. Most will tell you that tuning AFR is not what you should do. Many articles and books will tell you to run 12-13AFR(as thats where optimal burn lies) and then tune the ignition timing from there. We run richer AFRs simply because our engines were never meant for boost and we need a higher margin for error. Honestly, that AFR curve looks damn good except for it being slightly leaner than I'd want when full boost comes.</TD></TR></TABLE>

so say i pick a random point like 3psi and the car is at 13.8. thats a little more than slightly lean. you consider minimal half a point to be slightly lean? I'd understand a little more where you were coming from if this car was built or on 100 octane and up. but pump gas on a stock motor, come on


Modified by b16hybridsol at 9:24 AM 6/16/2006

yee SERIOUS

iTrader: (1)

from what i've read on HT (from being a detective and all) is that a slightily leaner afr can output more power. BUT from what i've learned from efi101 is that a slightily richer afr will promote the longetivity of the motor. so if we build cars for race, we can have whatever afr we want. if we want that "race car" to be daily driven, but you better richen up the afr a bit.

personally, if i was a tuner, i'd richen it up just so the customer doesn't blow. but **** happens right?

from that graph, i think sometimes we worry about how the power curve is more than the afr. truth is, if the curve is going up and it's afr is safe, move on to the next part.


Modified by undercoverdc2 at 10:16 PM 6/14/2006

LilCivic04

oh ok, thanks for clearing it up for me

b16hybridsol

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by undercoverdc2 &raquo;</TD></TR><TR><TD CLASS="quote">from what i've read on HT (from being a detective and all) is that a slightily leaner afr can output more power. BUT from what i've learned from efi101 is that a slightily richer afr will promote the longetivity of the motor. so if we build cars for race, we can have whatever afr we want. if we want that "race car" to be daily driven, but you better richen up the afr a bit.

personally, if i was a tuner, i'd richen it up just so the customer doesn't blow. but **** happens right?

from that graph, i think sometimes we worry about how the power curve is more than the afr. truth is, if the curve is going up and it's afr is safe, move on to the next part.

</TD></TR></TABLE>

all facts given though, it was a stock motor so it should have been played safer, and as i stated the motor melt cyl #3 so in all actuallity it was to lean flat out ... I was trying not to throw out names so if you could please delete that it would be appreciated.


Modified by b16hybridsol at 3:28 PM 6/14/2006

yee SERIOUS

iTrader: (1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16hybridsol &raquo;</TD></TR><TR><TD CLASS="quote">

all facts given though, it was a stock motor so it should have been played safer, and as i stated the motor melt cyl #3 so in all actuallity it was to lean flat out ... I was trying not to throw out names so if you could please delete that it would be appreciated.</TD></TR></TABLE>

i edited the post. just edit it out of the quote you did of me

b16hybridsol

ha opps... thanks

wantboost

iTrader: (2)

i think that curve sucks... no other way to put it

b16hybridsol

.dave

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PrecisionH23a &raquo;</TD></TR><TR><TD CLASS="quote">By theory, you don't do a lot of 5th gear pulls on the interstate due to drag (wind resistance). Once you are doing 100+mph your engine has to work even harder to overcome air drag. I cannot remember the conversion factor off the top of my head... but I believe the drag force is quadrupled once speed is doubled. It's been a while since I've taken fluid dynamics... all you internet engineers feel free to google up the equations This drag puts increased stress on your engine. So on a dyno this '5th gear factor' doesn't really apply. Of course there are other ways to counter drag as we all know and with a proper tune and precautions you can do 5th gear pulls to your hearts content.

Also, this tune is way too lean. Going into boost he is running way too lean and afterward 6500 it could be cleaned up a bit.</TD></TR></TABLE>

The 'v' in the equation for drag is squared, so yeah doubling your velocity and keeping everything else constant quadruples the drag force.

95c1v1cs1

Ok, ok, ok... I tuned the car. It was a terrible tune. It was so lean, yada, yada, yada. People like you kill me.

Andrew is a good friend of mine. This Pull was just to see what the turbo kit was capable of doing and was not recommended to run out on the street. If he did decide to do so, I told him I didn't know how long it would last. I explained this to Andrew before the car left. We did this pull only once for testing purposes and/or a glory pass and I realized it was a tad lean. Another 3% Fuel was added after the pull but another dyno pull was not made.

The car was meant to run on 8-9psi on the Street. 11psi on the Track WITH a RACE GAS mix or straight race gas.

A MBC was put on the car, multiple heavy load freeway pulls were made, and Pump gas was used. Thats a recipe for diseaster in my books and won't last long. Once again I recommended putting race gas in if he runs this at the track at 11psi. Out on the street is to uncontrolled and anything could happen.

I have no doubts in my mind that car would have ran 50+ Quarter Mile passes @ 11psi WITH a Race Gas Mix. No doubts. I have many cars already doing it that has lasted many years.

To each his own.

Corey Parrish
Slowmotion Motorsports
614-372-0304

Soccerking3000

he really shouldnt need race gas for only 11 psi, hell i ran 20 psi on 94 octane in my d-series...

b16hybridsol

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95c1v1cs1 &raquo;</TD></TR><TR><TD CLASS="quote">Ok, ok, ok... I tuned the car. It was a terrible tune. It was so lean, yada, yada, yada. People like you kill me.

Andrew is a good friend of mine. This Pull was just to see what the turbo kit was capable of doing and was not recommended to run out on the street. If he did decide to do so, I told him I didn't know how long it would last. I explained this to Andrew before the car left. We did this pull only once for testing purposes and/or a glory pass and I realized it was a tad lean. Another 3% Fuel was added after the pull but another dyno pull was not made.

The car was meant to run on 8-9psi on the Street. 11psi on the Track WITH a RACE GAS mix or straight race gas.

A MBC was put on the car, multiple heavy load freeway pulls were made, and Pump gas was used. Thats a recipe for diseaster in my books and won't last long. Once again I recommended putting race gas in if he runs this at the track at 11psi. Out on the street is to uncontrolled and anything could happen.

I have no doubts in my mind that car would have ran 50+ Quarter Mile passes @ 11psi WITH a Race Gas Mix. No doubts. I have many cars already doing it that has lasted many years.

To each his own.

Corey Parrish
Slowmotion Motorsports
614-372-0304</TD></TR></TABLE>

right on, that was the explaination i was looking for

jDMJeRk

I hate reading threads about how someones fuel curve is "choppy" or is all over the place. We recently had a customer post his dyno on the web for a turbo system that we put on his car, and he got a lot of negative responses about his a/f. I just wanted to note something when people are looking at the a/f graphs online. I've noticed just about EVERY dyno has the a/f table scaled down so small that ANYTHING looks smooth. I ran over to the dyno and pulled up some old dyno's as an example:


Pretty nice a/f huh?



Same dyno, just changed the size of the table...

Now back to the post... As far as your choppy fuel line, I wouldn't worry about it much. Yes it does look a bit lean, but another thing to think about is the location of the o2. We weld bungs into the downpipes about 1'-2' from the turbo and put the o2 in there vs using a sniffer. If you think you have an accurate reading, I would richin it up a bit under boost

Anyhow....

jDMJeRk

On the graphs... also think about mph vs engine speed...

EDIT AGAIN: And the smoothing

b16hybridsol

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jDMJeRk &raquo;</TD></TR><TR><TD CLASS="quote">I hate reading threads about how someones fuel curve is "choppy" or is all over the place. We recently had a customer post his dyno on the web for a turbo system that we put on his car, and he got a lot of negative responses about his a/f. I just wanted to note something when people are looking at the a/f graphs online. I've noticed just about EVERY dyno has the a/f table scaled down so small that ANYTHING looks smooth. I ran over to the dyno and pulled up some old dyno's as an example:


Pretty nice a/f huh?



Same dyno, just changed the size of the table...

Now back to the post... As far as your choppy fuel line, i wouldn't worry about it much. Yes it does look a bit lean, but another thing to think about is the location of the reader. We weld bungs into the downpipes about 1'-2' from the turbo.

Anyhow.... </TD></TR></TABLE>

by the choppy thing i was really talking about a couple dips in it not really the line as a whole. Regaurdless, this thread has been cleared up by the tuner.

david@didrace.com

A motor should not be seeing 14:1 A/F at 2 psi of boost using gasoline. Simple as that.

I've always let off on a full-throttle dyno pass if a boosted motor isn't seeing 12.5:1 A/F (gas) the second it hits boost. I also keep an eye on the A/F throughout the whole run and let off at any point if the A/F goes lean (above 12.5:1 A/F (gas)).

I thinks it's pretty shitty to do a WOT pull, hit boost, run lean and still do a full pull up to redline. It's totally unprofessional and pointless, unless the owner/operator of the dyno feels no responsibility for intentionally damaging a customer's motor.