That's exactly what I thought, but I've had detonation in this car before. That detonation event was accompanied with loss of power and that unmistakable sound that says this is gonna hurt. This was more of a metallic rattling sound. Strange.

 

what AFR's are you running in boost?

 

in 3rd gear it's 12-13, in the higher gears it appears to be 11-12. I have yet to go over about 6.5k rpm since the CAI install.

Here's a short example I recently made (low boost): http://ircimages.com/afr.wmv

 

I have way more power with the current setup than I did before the CAI and 10 afr's - it's insane at 11 psi and just half throttle, but I am not going to be comfortable till the AFR is somewhere between 10.5 to 11.2.

 

here is something to shoot for then.
11.5 = Approximate rich best torque at WOT
12.2 = Safe best power at WOT
13.3 = Approximate lean best torque

 

dont chase a/f's too much. Remember the 'other things".
I advise now with everyone that has FI to get a water meth system. cheap insurance.
olddragger

 

I'd be happy with 11 across the entire rev range, with a dip at 5.5k to 10.5 afr.

I don't think I have much need for a meth system.

 

i would go with 12.2, that way you have a little room to go either way if you need.


meth system? overkill

if you are worried about intake charge cooling, just upgrade the I/C

 

i'd love to replace my intercooler (Not that I really need to upgrade, but it's warm in FL in the summers and cooler is better). I just don't want to guess and have something that doesn't fit. And now I need to make sure any replacement doesn't go behind the low impact bumper cause my CAI is routed behind it.

 

i can read up on it for you. i have a turbo installation and tuning book that should have the proper sizes.

 

Well I got the AP. I know MM is away for the next few days, so should I load the base Cobb Map and see how things go? I don't even know what I'm looking for. Just so you guys know I have the MS CAI, MS exhuast, and RP supercat. I'm not to worried about fuel mileage, I just want to get the most out of my car as possible.

 

Mu ha ha..... I knew I would get this thread going again.

Hell, I get home from work and there is big o'l disscussion.

I've always thought of insulating the MAF pipe. Thats last on my list.

I pretty close to doing that now. Not many other things I can do for NA.
I still have a few tricks.

 

I guess I don't need to tell you those are N/A numbers.

 

Msql and Celronx, I have been seeing the samething with N/A

I think the explaination is throttle position and load.

Those are slightly changing because your foot is moving, I know I'm pedal to the metal so how can that happen.

I haven't studied it enough with the data logs to see if the A/F is changing due to slight postion differance in the throttle.

If the throttle remains the same and the A/F bounces then perhaps the load is changing due to wind resistance.


Back on the MAF issue, if velocity is effecting the MAF more than pressure, what about the position of the sensor? The question is:

Is the velocity decrease and sensor loaction enough to overide the pressure increase using a largertube size with FI applications.

I think the answer to this question is Yes.

 

I tend to be gullible when it comes to Wikipedia, since I don't know much. Now I'm really confused. So my initial hunch to side w/ dannobre is the current "correct" consensus?

Anyway, sorry to add to the topic diversion.

I'm hoping to contribute, if I can, to this thread after I receive the product.

 

Too.... much..... reading! HAHA.

Short version = Dan is MORE right than the stagnant pressure folks; but both of you are somewhat right; however the pressure changes you are talking about are very very very very small.

For example - when we flow 150 PSI through 300' of 3/8 ID diameter hose; we get 135 PSI to the divers (roughly) at 8 SCFM. When we need to flow the same 135 PSI to a diver through a 1/4 hose; we have to push 300 PSI. So flow velocity and total capable volume play WAY more of a roll than extra pressure from a larger tube.

In addition; if the MAF were that sensitive to changes in size; then a blow through setup would immediately peg once you entered boost.

 

haha, stagnant pressure sucks...


So, why does the Pettit system create such large maf readings? Something to do with temperature?

 

bernoulli stuff, the whole airfoil thing.

the top of the wing is "longer" so the air travels over it faster. Higher velocity = lower pressure. the bottom of the wing is "shorter" so air travels over it more slowly. Lower velocity = higher pressure. This generates lift...

It's kind of an abstract thing. Another example is blowing over the top of something, it creates a lower pressure and can suck liquid through the orifice. If you have an air compressor, a thin piece of tubing/needle (like to inflate a football), and a jar of water it's easy to do. Take the needle and put it in the jar of water, spray air over the needle and it will make a nice atomized mist. This form of atomizer is also found in perfume bottles...

 

eh, i guess, but that's really really different haha.

 

It's all about what we do/use I do a lot of flow calculations in rebreather diving applications....where screw ups are deadly. Luckily I haven't screwed up bad enough yet....

 

heat seeking missile...




You're approaching this too "structuredly", first you open your mind to accept the new idea, then build structure around it.

 

I dunno what to say, the atomizer experiment helped me understand it kinda.

I still don't fully understand what exactly is happening, only that it does and it definitely doesn't have many good analogies to describe it...

 

They had schools when you were young . Yeah I guess Aristotle did give classes

 

When you take an advanced fluid dynamics class, you learn Bernouli is given too much credit and the Kutta-Joukowski Theorem involving circulation around an airfloil is what really produces lift and the dP predicted by Bernouli can not make a modern airplane fly.

 

I hate to interupt the flow of this thread but I got the AP. I know MM is away for the next few days, in the meantime should I load the base Cobb Map and see how things go? I don't even know what I'm looking for. Just so you guys know I have the MS CAI, MS exhuast, and RP supercat.