Starting to lean out at 18psi on 93 petro...Magna

[Boosted_One]

Had her out today, made some timing adjustments, fuel tweaks etc.

 

So far 18-19 psi on 93 octane is tough to keep in the 12's on the A/F. I can get it into the 13's area but that is not enough.

 

I am going to dabble with the retard curve, but I am somewhat leary that some good octane booster and/or race petro is in need past 15psi. 15psi runs excellent on pump petro.

 

I can REALLY richen it up, but it'll still read in the 13's on the A/F gauge. I got it so rich it started to chug and still wouldn't drop into the 12's region.

 

Not that this is a surprise as 18 psi on a large 20G on 93 pump gas is asking for a lot.

 

She is DEADLY at 18psi!

 

We'll see what some more tuning will yield me.

[Quest4Power]

what size injectors are you running?

[Boosted_One]

Holley 75lb

 

Lots of room left in them.

 

It's not that I am not supplying enough fuel, it's the octane isn't high enough.

 

I still am going to try to get a little more out of it...

[TainterRacing]

what are you 8:1??? but any how I would not go much past 15psi On pump gas even with only 7:1  thats just me..

[Boosted_One]

You got it...8:1

 

I agree, I am doubtful past 15psi on pump gas is going to hack it.

 

I used to run 22 psi at times on my TBI... more boost is making it's way into the cylinders now with the MPI

[Joel]

Had her out today, made some timing adjustments, fuel tweaks etc.

 

So far 18-19 psi on 93 octane is tough to keep in the 12's on the A/F. I can get it into the 13's area but that is not enough.

 

I am going to dabble with the retard curve, but I am somewhat leary that some good octane booster and/or race petro is in need past 15psi. 15psi runs excellent on pump petro.

 

I can REALLY richen it up, but it'll still read in the 13's on the A/F gauge. I got it so rich it started to chug and still wouldn't drop into the 12's region.

 

Not that this is a surprise as 18 psi on a large 20G on 93 pump gas is asking for a lot.

 

She is DEADLY at 18psi!

 

We'll see what some more tuning will yield me.

 

Holley 75lb

 

Lots of room left in them.

 

It's not that I am not supplying enough fuel, it's the octane isn't high enough.

 

I still am going to try to get a little more out of it...

 

Mike,

 

I read your posts (as quoted above) and I'm confused.

 

Octane doesn't increase richness or the likes, just resistance to knock.

 

If you have plenty of pulse width left on those injectors (with 800cc's or so you should!), you should be able to tune it in right.

 

What engine management are you running? SDS? Make sure your maps are smooth! Hills in the map are gonna make things run odd. I haven't seen your maps, but I know this is a common mistake.

 

18psi on 93pump should definately be doable, unless its knocking.

 

What are you using to test your A/F ratio? if your using a narrow band O2 sensor, I can tell you that what your experiancing is MUCH different then the "reported" O2 readings. Narrowbands will not read accurately at all except for a narrow area (14.3-14.9:1 or so) and the farthar away it gets from that, the worse off the readings become.

 

I can tell you from personal experiance with a NB A/F gauge/o2 sensor that I have gotten 13:1 or so on the gauge and 9:1 A/F on an external wideband at a dyno.

 

 

Joel

[Dcrasta]

Hey mike sounds like you got that thing running sweet.  What are your intake temps like?  Maybe if u can get the charge a little cooler u can get a better A/F reading.  Density wise know what I mean?

 

Hugh

[Shelby]

Joel you said >>What are you using to test your A/F ratio? if your using a narrow band O2 sensor, I can tell you that what your experiancing is MUCH different then the "reported" O2 readings. Narrowbands will not read accurately at all except for a narrow area (14.3-14.9:1 or so) and the farthar away it gets from that, the worse off the readings become.

 

I can tell you from personal experiance with a NB A/F gauge/o2 sensor that I have gotten 13:1 or so on the gauge and 9:1 A/F on an external wideband at a dyno.  

 

 

Joel

 

is their any   02 sensors that we can use that will give a better reading  on the air fuel mix or whats the best one to use

[Boosted_One]

Mike,

 

I read your posts (as quoted above) and I'm confused.

 

Octane doesn't increase richness or the likes, just resistance to knock.

 

If you have plenty of pulse width left on those injectors (with 800cc's or so you should!), you should be able to tune it in right.

 

What engine management are you running? SDS? Make sure your maps are smooth! Hills in the map are gonna make things run odd. I haven't seen your maps, but I know this is a common mistake.

 

18psi on 93pump should definately be doable, unless its knocking.

 

What are you using to test your A/F ratio? if your using a narrow band O2 sensor, I can tell you that what your experiancing is MUCH different then the "reported" O2 readings. Narrowbands will not read accurately at all except for a narrow area (14.3-14.9:1 or so) and the farthar away it gets from that, the worse off the readings become.

 

I can tell you from personal experiance with a NB A/F gauge/o2 sensor that I have gotten 13:1 or so on the gauge and 9:1 A/F on an external wideband at a dyno.

 

 

Joel

 

I am running the SDS 4E. My fuel maps and MAP values are very linear.

 

I run a 20G with a Garret compressor trim that flows 735cfms with a TDO6H exhaust wheel.  18psi is a lot to try to get out of a 93 octane reformulated ethanol blend.

 

I can literally get the car to chug from runing it rich but the motor still wants to sit in the 13's area and was lightly pinging.

 

Intake air temps with the FUSO IC are holding very good numbers, never higher than 10 degrees above ambient temps.

 

I still am playing with it but with 8:1 compression and the turbo flowing 735+ cfms I am not so sure about getting higher boost without retarding timing too much without the aid of higher octane fuel.

 

Yes, using a run of the mill 3 wire O2.

[Joel]

I am running the SDS 4E. My fuel maps and MAP values are very linear.

 

I run a 20G with a Garret compressor trim that flows 735cfms with a TDO6H exhaust wheel.  18psi is a lot to try to get out of a 93 octane reformulated ethanol blend.

 

I can literally get the car to chug from runing it rich but the motor still wants to sit in the 13's area and was lightly pinging.

 

Intake air temps with the FUSO IC are holding very good numbers, never higher than 10 degrees above ambient temps.

 

I still am playing with it but with 8:1 compression and the turbo flowing 735+ cfms I am not so sure about getting higher boost without retarding timing too much without the aid of higher octane fuel.

 

Yes, using a run of the mill 3 wire O2.

 

You cannot get a good estimate at all on what your A/F ratio is with a Narrow band O2.

 

Your better off with an EGT, going to a dyno and finding out which side of the EGTs your on.

 

If you can get her to chug, you're hitting the 9-10:1 area. You'll want to run that much fuel (between 10.5-11:1) if you on 24+psi of boost, but not before then. Fuel wash is no good of coarse.

 

My suggestion to you would be to get that thing on a wideband before continuing. If you have an EGT gauge, use it. EGT's should not exceed 1450 or so on pump with an aluminum head. On leaded gas (104+ MON) you could get to the 1600-1640F mark. Beware of the cold EGTs when you know better. That means your gonna blow it if you don't get off it.

 

Those A/F gauges are useless for any kind of tuning at all, unless you want to tune for Stioch, which means your to lean for your application. If you see Red LEDS on that thing with 18psi, you've probably already toasted the motor.

 

I know Widebands are expensive, but thats not gonna help the fact that narrow bands don't help one tune real well. The Nb o2's will get you running, but for all out power an EGT will do you more justice.

 

I would suggest perhaps a knock light, such as a KnockLink by Link or an MSD knock meter. I would not use it to tune with period (thats tuning to the absolute threshold, which is bad on a street car), but rather use that as a warning system... If you see it turn into a pretty Xmas tree, get off it and figure out whats wrong.

 

I figured your maps were pretty linear, as your running awefully good 15psi and under, but you never know No offense intended. You're much farther along on your car than I am on mine, I think its wonderful how well your doing!

 

How far does your Retard go? I would not go below 8BTDC, your EGT's will likely skyrocket, and things will start to get real warm below that.

 

At 18psi if you revved to 6000RPM, your motor will consume only 577CFM. That would be on a 16G, 20G, 25G, To4e and so on.

 

Your static compression ratio is around 16.5... so you would be correct in the assumption that perhaps 18psi is a tad much on pump. But, considering that fact, you've gotten rather far up there before requiring a "tad" higher octane.

 

Joel

 

Joel

[Boosted_One]

This tuning I am doing is only the prelimery to the dyno. So I am getting it close and go from there once on the rollers.

 

My A/F gauge looks like this:

 

http://www.westach.com/images/showcase/2C5-56-Air_Fuel_Ratio.jpg

 

It is quite more the tuning tool than the standard LED type.

 

I was quite impressed last year when comparing my dyno runs A/F and the A/F gauge I use. The NB A/F gauge was not far out of the ballpark to the dyno info.

 

The amount of retard I can do is up to 20 degrees on the SDS.

 

I also use a knock sensor on the SDS.

 

I do have an EGT but the probe is kaput.

 

I originally told myself no more than stock boost till the dyno, and now I am running 15psi. LOL!

 

How did you come upon the motor wil only consume 577 cfms? If that were the case a 20G would do the same thing as a super16G...just curious

 

BTW...at 15 psi the 75lb injectors are at 62% duty cycle...glad I went with the 75lb.

[Joel]

I still would get real cautious with the NB A/F gauge... Nice looking gauge, but I think the NB O2 sensor doesn't do it justice!

 

As far as the CFM an engine takes in, the Turbo does NOT dictate that, against popular belief.

 

The VERY thing that makes a motor consume more air than it could normally aspirated is boost (duh, right?). We often loose sight of that when purchasing big turbos.

 

Take a stock motor, 2.6L, ~2600ccs, ~157Cuid (probably more like 158). My statement to you I did quick math at 150Cuid (rough conversion).

 

Ok, to figure out CFM, you do some math at 100% efficiency (cause thats all the data I have).

 

As a motor spins, on a 4 cycle engine, only half the cylinders will take in air per RPM as dictated by the cam (4 cycles are completed in 720 crank degrees). So, 158/2 = 79

 

Now we need to know frequency, how many times this occurs per unit of time (RPM), which if we RAP out to 6000RPM, we will do 79*6000(rpm) = 474,000, now convert to cubic inches 474,000/1728, you get 274.305~ ( we will round to 274).

 

Thats normally aspirated... meaning at 100% efficiency (which is not likely), you will take in 274cfm.

 

To figure out how much consumption you will have after you have applied boost, you need to multiply that number by the boost ratio.

 

Boost ratio = (boost)+14.7/14.7, in your case 18. 18+14.7/14.7 = 2.224pr

(You add 14.7 to your 18psi because this is NOT relative pressure, we are dealing with absolute, if you are at 1 mile up like me, to get exacts, you would need to know what atmospheric pressure is).

 

Now, Take 274*2.224 = 609CFM. Theres your number. Remember the reason why this "works" is that this is based on what happens at atmospheric. HOWEVER, You WILL not get this number in even the best scenerios... this is 100% efficiency. You numbers will be more dictated by your cam, how well your head flows, and the like. You will likely be UNDER this number some.

 

This prompted me to make a Web script calculator (took me about an hour to perfect somewhat).  

 

GOTO: Http://www.tristarion.com/boostcalc.php

 

Joel

[Joel]

Anyone play with that calculator?

 

Joel

[kev]

Yeah I was.  Pretty cool I might say.  So running at 15 psi is over 200% better than N/A.  That is great!!  

 

kev

[Joel]

Be warned (as stated above) that those numbers are at 100% efficiency. I would say that you would MAX OUT at 80% efficiency on the stock intake/head w/ an exhaust system on it.

 

Joel

[JoshA]

Also remember that the volumetric efficiency will be at it's peak right around the torque peak of the engine.  And we've seen how quickly these things fall on their face after 4000 RPMS.  So it is unlikely that you will push much more than 500 CFM at 6000 RPM(18psi).  It's really hard to say for sure without better VE information.  But generally a long stroke, 2-valve motor like this is going to be pretty poor at moving air at high RPMS.

 

I know that this is an old thread, but I was searching for some stuff and figured that I'd add my take.

 

I'd be curious if anybody could convince me that this is incorrect before I go and buy a turbo sized according to these estimations.  Right now, I'm leaning towards a TO4E-46 trim compressor.  http://www.majesticturbo.com/20574-46.html

 

My calculations put max airflow in lbs/min to be less than 40 @ 120 degrees, 6000rpm, 18psi.

[MarioG]

Don't forget the fuel pump!  At one point I was has having fuel supply issues despite having large injectors.  After testing the pump I was shocked to find that it couldn't even supply the amount that the injectors could at 45 psi, let alone under boost.  I have since switched to the SX pump, which looks like a cannon and is pretty noisy but will definately fulfill your needs.

Later,

Mario.

[Boosted_One]

The SX pump huh? Hmm any links to it?

 

What pump did you have in it? I got that 125psi "CNM" pump.

[heefner]

Mike if thats all you have, it might not be enough.  I got my pump with the old package 3 (turbo, cam, valvesprings, fuel pump...).  My car will lean out at anything above 10psi and 3500rpms with just the cnm upgraded pump. I ran into a leaning out problem this summer and it turns out that the relay for my inline fule pump wasn't getting a good ground.  It was only running on the CNM pump.  

[MarioG]

I was running TEP's "400hp" Bosch pump.  The manufacturer's link for the SX pump is:

 

 

http://www.essexind.com/sx_page2.htm

 

Do a search on yahoo for venders if your interested in buying one.

Later,

Mario.

[Heron]

;D As I said, nothing like having the experts with us!!!!! ;D

Men I wish I had half of that knowledge!!!! ;D

Regards,

Heron

[jinx]

Interesting tuning info

 

DSMs use a fast acting EGT probe; http://www.teamrip.com/

 

so Mike, you found the westach A/F reading pretty close to the wideband ? That should keep you in the ballpark at least

 

here's some wideband info. Guys local to each other may split cost.

http://www.techedge.com.au/ control box, display, and cables ~ US$270

Uses 92-95 Honda Civic VX O2 reads 0-5 volts, available Napaonline $139 for the L1H1

guys at www.diy-efi.org originally developed circuitry for free use and apparently these guys copied it to offer a kit

 

knock sensor tuning works great for DSMs but I guess with standalone, you can't datalog and watch for the "counts" or see when the ecu "smells" trouble and starts to retard timing

 

All that CFM math stuff gives me a headache, so I spend more time picking apart "real world" results. Yes you can have a turbo too small that can't keep up with the demands of the motor in the upper rpms. Many sucessful combinations just concentrate on eliminating restrictions with solid tuning. You see DSMs run 12s with 14b and nissan sr20det do it with oe T25s... then you see guys with bigger turbos run slower. You often see folks jumping on the ball-bearing turbo bandwagon and barely put up better numbers than their old 16g or 20g... then comes a next barrage of mods as if they're scambling to convince themselves, the turbo was the "right" move

 

Anybody run the MSD "500hp" pump ?  I'll drop my tank and modify it for an in-tank GN, or DSM, or... before I put in a noisy inline. Can't deal with that

[Boosted_One]

Jinx

 

 

My opinion about narrow band are quite different. While I was dynoing the actual wideband O@ from the dyno was reading quite differently than my narrow band. In fact the narrow band is so far off that I would deem it as completely useless!

 

I am going to go with a wideband O2 and toss the narrow band. It's not accurate enough to tune correctly.  :-/

 

I do have knock sensing on the SDS. It'll throw up a K in the timing window indicating knock, but no datalogging.

 

My next approach will be a wideband O2 along with the EGT gauge.

 

20G is geting pulled.... will be mounting a T04B and header next.

[JoshA]

Jinx

 

My opinion about narrow band are quite different. While I was dynoing the actual wideband O@ from the dyno was reading quite differently than my narrow band. In fact the narrow band is so far off that I would deem it as completely useless!

 

I agree, narrow band O2 sensors are pretty much useless.  Wideband and EGT is the only way to get tuned properly.

[chiplee]

Mike I was really wondering how you were getting it to sputter at 13.  I didn't know for sure that that was so strange 'till I saw my car pull smoothly with A/F at 9.  It didn't stutter till it' got almost to 8.  Some day I'll do the same thing and just break down and get a wbo2 sensor but for now I'm happy.