Pettit Super Charger Owners
03-09-2008, 12:25 AM
#1426
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What do you mean? You mean MAF numbers?
To go to a flash, you should remove the idle bleed hose so that everything is going through the TB.
The MAF tube that Pettit is shipping is a complete piece of junk.
Besides the fact that it is 7% over-size, the taper is too close to the MAF and the inlet, being so soon after the filter, really screws up the flow.
That said, recalibrating the MAF signal to the PCM was a task, but I managed it. The idle ranges (flow under ~8 g/sec max) needed their own, different slope from most of the rest of the response curve.
Basically, what is normally a nice, smooth arc turns into a bit of a hula dance.
But it works.
To go to a flash, you should remove the idle bleed hose so that everything is going through the TB.
The MAF tube that Pettit is shipping is a complete piece of junk.
Besides the fact that it is 7% over-size, the taper is too close to the MAF and the inlet, being so soon after the filter, really screws up the flow.
That said, recalibrating the MAF signal to the PCM was a task, but I managed it. The idle ranges (flow under ~8 g/sec max) needed their own, different slope from most of the rest of the response curve.
Basically, what is normally a nice, smooth arc turns into a bit of a hula dance.
But it works.
We measured 3.405" diameter on the MAF housing I've got. We averaged 3 measurements with a caliper I had in my garage thats accurate to the mil (milli-inch). MM said the stock MAF tube is 3.375 (3 3/8 "). The areas of both work out as such:
stock 3.375" diameter -- A = pi * r^2 -- 8.94618 in^2
my MAF 3.405" diameter -- 9.10593 in^2
percent accurate against stock: (9.10593 - 8.94618) / 8.94618:
1.78%
Sorry Jeff if I misinformed you about the 7%-- Indeed I was the one with the calculater that night so it was probably my error.
Also, during my install at 7stock, Cam/Moon said my housing was a prototype that they had manually machined. I don't think everybody here has my MAF housing exactly, but I think 1.78% will easily auto-correct with STFT/LTFT?
Indeed there is something very strange about the MAF flow at idle, but I watched as Jeff eventually got it tuned perfect -- 1100-1200 RPM rock-solid idle. The test drive showed none of the quirks of the Int-X loaner I have: inconsistant idle, APV valve "clicking" on/off at idle, and the non-linear surge of torque around 3-4k at partial throttle. It would seem as if the Cobb tools allowed Jeff to tune for the Pettit S/C in a single evening which IMHO is very impressive and a testament to both Jeff and Cobb!
The AP unit itself is very cool with its LCD screen -- I especially liked the realtime digital gauge modes (AFR/IAT/ECT/STFT/MAF readings)
03-09-2008, 12:33 AM
#1427
What do you mean? You mean MAF numbers?
To go to a flash, you should remove the idle bleed hose so that everything is going through the TB.
The MAF tube that Pettit is shipping is a complete piece of junk.
Besides the fact that it is 7% over-size, the taper is too close to the MAF and the inlet, being so soon after the filter, really screws up the flow.
That said, recalibrating the MAF signal to the PCM was a task, but I managed it. The idle ranges (flow under ~8 g/sec max) needed their own, different slope from most of the rest of the response curve.
Basically, what is normally a nice, smooth arc turns into a bit of a hula dance.
But it works.
To go to a flash, you should remove the idle bleed hose so that everything is going through the TB.
The MAF tube that Pettit is shipping is a complete piece of junk.
Besides the fact that it is 7% over-size, the taper is too close to the MAF and the inlet, being so soon after the filter, really screws up the flow.
That said, recalibrating the MAF signal to the PCM was a task, but I managed it. The idle ranges (flow under ~8 g/sec max) needed their own, different slope from most of the rest of the response curve.
Basically, what is normally a nice, smooth arc turns into a bit of a hula dance.
But it works.
Cheers,
Hymee.
03-09-2008, 01:16 AM
#1428
However, the engine will flow an awful lot of air before the TB becomes a real restriction as it stands.
The DBW system is limited to a duty cycle considerably less than 100%. I'd be interested in seeing what the actual opening angle is at max DC.
I suppose I could just hook one up out of the air loop and look at it whilst someone stood on the pedal, but that would be way too easy.
We measured 3.405" diameter on the MAF housing I've got. We averaged 3 measurements with a caliper I had in my garage thats accurate to the mil (milli-inch). MM said the stock MAF tube is 3.375 (3 3/8 "). The areas of both work out as such:
stock 3.375" diameter -- A = pi * r^2 -- 8.94618 in^2
my MAF 3.405" diameter -- 9.10593 in^2
percent accurate against stock: (9.10593 - 8.94618) / 8.94618:
1.78%
Sorry Jeff if I misinformed you about the 7%-- Indeed I was the one with the calculater that night so it was probably my error.
stock 3.375" diameter -- A = pi * r^2 -- 8.94618 in^2
my MAF 3.405" diameter -- 9.10593 in^2
percent accurate against stock: (9.10593 - 8.94618) / 8.94618:
1.78%
Sorry Jeff if I misinformed you about the 7%-- Indeed I was the one with the calculater that night so it was probably my error.
The tube they are shipping now looks exactly the same.
03-09-2008, 04:53 AM
#1429
The DBW system is limited to a duty cycle considerably less than 100%. I'd be interested in seeing what the actual opening angle is at max DC.
I suppose I could just hook one up out of the air loop and look at it whilst someone stood on the pedal, but that would be way too easy.
I suppose I could just hook one up out of the air loop and look at it whilst someone stood on the pedal, but that would be way too easy.
)I should have video'ed it when I was experimenting with the DBW a few weeks back.
Cheers,
Hymee.
Last edited by Hymee; 03-09-2008 at 04:54 AM. Reason: I'm incapably of spelling correctness
03-09-2008, 07:38 AM
#1430
Can someone with an aftermarket O2 sensor log both the aftermarket and the factory O2 readings at the same time for a comparison? It might be helpful for those thinking of doing an aftermarket installation to see how the two stack up.
03-09-2008, 08:16 AM
#1431
That doesn't mean that 100% = 90°, though.
They are pretty spot on from 12:1 up to 19:1. At either end, the OE sensor wanders out to .2 or so max before it taps out at 11:1 and 20:1.
03-09-2008, 08:47 PM
#1432
Thanks for the clear up Hymee and thanks Jeff for the info. i was thinking just that.
Just for info--i dont have an idle air bleed any longer--everything is through the maf. I have the pettit flash and that has the their maf pipe calibration along with it(duh).
I was wondering about the short distance from the intake side to the maf and air distortion. Cam advised NOT to run a screen. i am thinking about using the racing beat filter with their horn mated onto the Pettit pipe, but i want to be careful about deviating from the way the tune is set. In your opinion would that be of some help?
thanks again and good work guys.
olddragger
Just for info--i dont have an idle air bleed any longer--everything is through the maf.
I have the pettit flash and that has the their maf pipe calibration along with it(duh). I was wondering about the short distance from the intake side to the maf and air distortion. Cam advised NOT to run a screen. i am thinking about using the racing beat filter with their horn mated onto the Pettit pipe, but i want to be careful about deviating from the way the tune is set. In your opinion would that be of some help?
thanks again and good work guys.
olddragger
03-10-2008, 04:52 AM
#1434
Jeff,
Thank you for your opinion. Now-
Opinions are nice, but can someone log some data and post it so that others can form their own opion as to how close an aftermarket sensor is to the stock one?
Last edited by lolachampcar; 03-10-2008 at 05:02 AM.
03-10-2008, 05:23 AM
#1435
I don't have any documented evidence, I should be able to find some as I have plenty of Motec logging from Wildcards blown RX-8. But I do remember "Grandad" telling me when I did the very first prototype of a scan tool that they were that close it didn't matter. He had a Motec Lambda sendor and controller in my car, and I had the prototype software running, and we also had the old "Ric Shaw" piggy back plugged in as we took a trip the the MazFix dyno. And there we stuck the dyno dynamics lamba sensor up the other tail pipe. So we had 3 going at the time. Kicking myself now for now "recording" it for prosperity. That was way back in very early 2004.
But yes, some empirical results would be great to see.
Cheers,
Hymee.
But yes, some empirical results would be great to see.
Cheers,
Hymee.
Last edited by Hymee; 03-10-2008 at 05:26 AM.
03-10-2008, 08:36 AM
#1436
Jeff--no such hose now. The only thing coming out of the maf pipe is the vacumm for the omp and jet air. The hose I believe you are referring too is now directly and only attached to the purge valve. Not much action there.
On the Pettit maf pipe--, the latest pipe from them looks pretty good to me. Maf mount is tight and it is smaller than RB's pipe and most importantly that is the pipe that the flash is tuned with. I agree. I also would like to have a longer course of air before the maf picks it up but we are spaced challaged. Some data logging would still be good considering car to car differences also. Within the month I hope to get a good collection of data with the logger.
olddragger
On the Pettit maf pipe--, the latest pipe from them looks pretty good to me. Maf mount is tight and it is smaller than RB's pipe and most importantly that is the pipe that the flash is tuned with. I agree. I also would like to have a longer course of air before the maf picks it up but we are spaced challaged. Some data logging would still be good considering car to car differences also. Within the month I hope to get a good collection of data with the logger.
olddragger
03-10-2008, 09:13 AM
#1437
Since the purpose of equalizing screens is to replicate a longer MAF tube, I wonder why Cam noted to not use a screen? Especially since the MAF sensors are already hyper-sensitive.....
03-11-2008, 05:54 AM
#1440
No matter how smart I may or may not think I am, I do not expect others to take my opinion as fact just because I post a lot, run my mouth and say "it is so". I try to provide data so others can form their own opinion. I've also been around long enough to have been wrong on many an occasion so I know I do not know everything.
For instance, if I were to say that I did such and such to a turbo installation and got so and so results, I'd post the data and say "I think this is what is going on, anyone have a different opinion?". I'd probably post the file too so others could give it a try but I think I know how you feel about that.
03-11-2008, 06:01 AM
#1441
I don't have any documented evidence, I should be able to find some as I have plenty of Motec logging from Wildcards blown RX-8. But I do remember "Grandad" telling me when I did the very first prototype of a scan tool that they were that close it didn't matter. He had a Motec Lambda sendor and controller in my car, and I had the prototype software running, and we also had the old "Ric Shaw" piggy back plugged in as we took a trip the the MazFix dyno. And there we stuck the dyno dynamics lamba sensor up the other tail pipe. So we had 3 going at the time. Kicking myself now for now "recording" it for prosperity. That was way back in very early 2004.
But yes, some empirical results would be great to see.
Cheers,
Hymee.
But yes, some empirical results would be great to see.
Cheers,
Hymee.
I know you are buried busy. If you get a free minute to post the data I think it would be helpful. I trust the factory sensor but there may be others out there that want to see some proof before they trust it to do their own tuning.
Thanks, Lola
03-11-2008, 06:17 AM
#1442
I've got heaps of MoTeC logging. I've got lots of CSV logs of sCANalyser Live. Some of them might even be from Wildcard's car when we had the MoTeC bung in it as well. But I think I would have a very difficult time finding it all, and then correlating it. It would be quicker for me to do some fresh logging with what I have, and borrow a MoTeC from Grandad. But I don't want to put a bung in my pipe at the moment, so it will have to be up the tail pipe. And then someone will argue with that...
What I need to do is look at the "calibration" curve with sCANalyser Live V2, cause I can log the Lambda as well as the volts (current?) as reported to the PCM.
Cheers,
Hymee.
What I need to do is look at the "calibration" curve with sCANalyser Live V2, cause I can log the Lambda as well as the volts (current?) as reported to the PCM.
Cheers,
Hymee.
03-11-2008, 06:32 AM
#1443
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would using an AEM CAI help with this particular situation?
03-11-2008, 09:55 AM
#1445
Jeff knows a lot more about the details of one CAI/intake pipe dimension versus another than I do. We were talking about comparisons between the AEM/MazdaSpeed and K+N the other day but I can't remember what we discussed.
Perhaps he'll chime in and re-explain it.
03-11-2008, 12:00 PM
#1446
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Jeff knows a lot more about the details of one CAI/intake pipe dimension versus another than I do. We were talking about comparisons between the AEM/MazdaSpeed and K+N the other day but I can't remember what we discussed. Perhaps he'll chime in and re-explain it.
Perhaps he'll chime in and re-explain it.
03-11-2008, 06:55 PM
#1447
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im thinking.....and by all means correct me if im wrong.....
the AEM CAI is much longer and actually goes into the nose...
therefore, would the air thats going in be much more stable as it reaches the MAF sensor?
the AEM CAI is much longer and actually goes into the nose...
therefore, would the air thats going in be much more stable as it reaches the MAF sensor?
03-11-2008, 07:37 PM
#1450
I'm not sure if the vehicle that I just worked with had a screen or not.
Since the idle is so high on the Pettit application, the accuracy of the low-end flow isn't as important.
I'd suggest it, but getting the MAF tube out to a proper length is going to be more important.
Since the idle is so high on the Pettit application, the accuracy of the low-end flow isn't as important.
I'd suggest it, but getting the MAF tube out to a proper length is going to be more important.