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Old 09-29-2009, 12:20 PM   #26
Bizko1288
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Quote:
Originally Posted by NSFW View Post
Can anyone out there who is running blow-through post a datalog that shows how much IAT moves around? It would be interesting to see how far apart the extremes are, though I'm not sure how to guesstimate the actual rate of change vs. the rate of change reported by the IAT sensor.
Bump for this info?
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Old 10-05-2009, 11:19 PM   #27
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I have blow thru on my car it was bugger to get to idle at first. However when I did my swap I changed too many things all at once so i have struggled with tuning a blow thru, modded injectors, bigger turbo, and fMIC, tumbler deletes all at once. It is a work in progress.


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Old 12-09-2009, 10:17 PM   #28
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bump anymore info on this subject?
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Old 12-10-2009, 06:51 AM   #29
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I've been working with OS blow-thru and it's been much better for me than draw thru. In my experience, the car runs smoother with much less learned afr corrections. I've had no problems what so ever with it.

I think those that do have trouble with it just forget to delete the PCV valve and have an air leak in that location not knowing it.
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Old 12-23-2009, 10:52 AM   #30
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My blow thru tuned just fine. Tuners don't like them because they are lazy. Most tuners have base maps for draw through and have very little tuning to do on typical setups.

It's a little harder initially but once you get the curve the way you want it it's stupid easy to make changes. My tuner took a little while initially but once he got the curve flattened and tweaked we started making very fast progress.
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Old 12-27-2009, 10:15 AM   #31
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well thats good to hear thanks guys
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Old 12-27-2009, 02:27 PM   #32
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Is anyone running a GT30-sized turbo with blow-through and a 3" MAF housing?

I'm going to switch to blow-through for my ATP 3076, I have 3" and 3.5" tubing available, and I don't want to go with 3.5" if 3" will suffice.

Thanks!
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Old 12-27-2009, 04:04 PM   #33
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I'm running a 70mm (smaller than 3") blow thru on my GT35R. My MAF maxed out but I'm on the 2.0L ECU which cannot read as high as the 2.5L ECU's can.
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Old 12-27-2009, 04:21 PM   #34
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The older ECUs have a limit on the airflow they'll understand (I think it's 300 g/s or something like that) but the thing that interests me the most is whether the MAF voltage maxed out in your setup. Do you have any data logs that show the MAF voltage?

How did your tuner get around the MAF being maxed out? It's common to just redo the MAF sensor scaling so that the ECU only "sees" half of the actual airflow, and then rescale the injectors so the ECU only "requests" half as much as they actually flow, so you end up with proper AFRs in the end. If your tuner took that approach and got your car working well with a sub-3" blow-through then I may just stick with a 3" tube...

I get the impression there have been different sensors used in different years though - does yours look like this? [click here]

Thanks!
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Old 12-27-2009, 05:50 PM   #35
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Quote:
Originally Posted by NSFW View Post
The older ECUs have a limit on the airflow they'll understand (I think it's 300 g/s or something like that) but the thing that interests me the most is whether the MAF voltage maxed out in your setup. Do you have any data logs that show the MAF voltage?

How did your tuner get around the MAF being maxed out? It's common to just redo the MAF sensor scaling so that the ECU only "sees" half of the actual airflow, and then rescale the injectors so the ECU only "requests" half as much as they actually flow, so you end up with proper AFRs in the end. If your tuner took that approach and got your car working well with a sub-3" blow-through then I may just stick with a 3" tube...

I get the impression there have been different sensors used in different years though - does yours look like this? [click here]

And yes mine looks like that. The older ECUs could only see like 300 g/s where the 2.5L Ecu's can see 500 g/s.

Thanks!

My MAF was rescaled. I have more headroom but not a whole lot more. I'm boosting 22 psi on my hybrid and making 424 hp on a Mustang dyno. Tq is 415. Timing is super conservative at 16 at redline on methanol injection. Spring time we are bumping up everything. We wanted to keep it conservative since the new motor only had 500 miles on it.
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Old 01-01-2010, 07:57 PM   #36
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Keep in mind that the charge tends to carry oil particles and/or fumes from the turbo compressor or vent breather (depending of your setup). In order to keep an accurate reading you will have to clean your MAF at least once a month, if not once a week. Also, oil will permanently stain the red hot element after a while so you will have to replace it eventually.
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Old 01-01-2010, 08:49 PM   #37
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Quote:
Originally Posted by jardamuth View Post
Keep in mind that the charge tends to carry oil particles and/or fumes from the turbo compressor or vent breather (depending of your setup). In order to keep an accurate reading you will have to clean your MAF at least once a month, if not once a week. Also, oil will permanently stain the red hot element after a while so you will have to replace it eventually.
Are you running a blow-through MAF, or do you know someone who is?

This is the first I've heard of short-lived sensors like that.
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Old 01-01-2010, 10:12 PM   #38
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I haven't go blow-thru on a subaru but I did it on several car such as Suzukis, LS1 engines etc.

Beside, electronics are pretty much the same so it doesn't really matter. I'm not saying that their life will be shortened, but rather that they'll lose accuracy over time.
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Old 01-02-2010, 09:47 AM   #39
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I wish cobb would come out with SD maps and tuning support for 16 bit ecu's
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Old 01-02-2010, 10:34 AM   #40
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I wish cobb would come out with SD maps and tuning support for 16 bit ecu's
Not gonna happen from what Cobb told me. And OS has SD for the 16 bit ECU's.
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Old 01-02-2010, 12:13 PM   #41
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Quote:
Originally Posted by Bad Noodle View Post
As far as rich dips go with fmics.... I've been trying to tune mine out for months, but eventually gave up. After 167 map revisions, I just accented it as part of the characteristics of the setup.

Theoretically, placing the maf post IC in the airstream would actually cut down on temp variation. The air going into your TB shouldn't be hotter than 130F and you get that on the intake with heatsoak pretty easily on some days.

Besides rescaling the maf, there might be some other things that might need to be changed. I haven't looked through RR, but I would assume you need to keep an eye on any tables that have temperature along the axis. Like TD temp corrections.

I've heard that all some people did was scale the maf and everything was good to go. My guess is that tuners don't like blow through because they have less experience with it and there is more for the customer to messup on the install if it's a diy job.
The volume of a FMIC and its tubing is considerably larger than the TMIC. It takes longer to fill that volume at the same level of pressure. The ECU isn't programmed to support the new delay. It has metered the air but the FMIC hasn't acually reached full boost. So the full is dumped early.
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Old 01-02-2010, 12:48 PM   #42
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The volume of a FMIC and its tubing is considerably larger than the TMIC. It takes longer to fill that volume at the same level of pressure. The ECU isn't programmed to support the new delay. It has metered the air but the FMIC hasn't acually reached full boost. So the full is dumped early.
But going blow thru after the Intercooler would solve that wouldn't it?
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Old 01-02-2010, 03:13 PM   #43
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But going blow thru after the Intercooler would solve that wouldn't it?
I hope so, because the whole reason I'm going blow-through is to solve that problem.
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Old 01-03-2010, 03:05 AM   #44
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I hope so, because the whole reason I'm going blow-through is to solve that problem.
I have a blow-thru setup and do not experience the rich dip.
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Old 01-03-2010, 03:37 AM   #45
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Cool, good to know. I have some questions, if you don't mind...
What turbo?
What diameter is the tubing at the MAF sensor?
How many grams per second is your MAF reading? And how many volts?

I'm trying to figure whether I need 3" or 3.5" tubing.

Thanks!
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Old 01-03-2010, 10:37 AM   #46
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Quote:
Originally Posted by CoolRex View Post
Not gonna happen from what Cobb told me. And OS has SD for the 16 bit ECU's.
Why not? I feel like OS is kind of primitive compared to the many features that AP has, and Cobbs software seams much easier to use. Is there any way to use a sort of hybrid setup of AP and OS?
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Old 01-03-2010, 01:40 PM   #47
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Why not? I feel like OS is kind of primitive compared to the many features that AP has, and Cobbs software seams much easier to use. Is there any way to use a sort of hybrid setup of AP and OS?
They haven't released it for the STi yet. It's still in beta. Too much development and time involved and the 16Bit ecu no longer exists in newer cars.
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Old 01-04-2010, 06:13 PM   #48
chuckdez
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Quote:
Originally Posted by NSFW View Post
Cool, good to know. I have some questions, if you don't mind...
What turbo?
What diameter is the tubing at the MAF sensor?
How many grams per second is your MAF reading? And how many volts?

I'm trying to figure whether I need 3" or 3.5" tubing.

Thanks!
I'm still running the VF39. Planning on a FPGreen HTA or ATP GT35R.

I forgot the dimensions of the Perrin tube.

Here is my MAF scaling, the most I've pulled is 320 g/s or so @ 11.0 AFR.
Code:
0.94	0.98	1.02	1.05	1.09	1.13	1.17	1.21	1.25	1.29	1.33	1.37	1.41	1.48	1.56	1.64	1.72	1.80	1.88	1.95	2.03	2.11	2.19	2.27	2.34	2.42	2.54	2.66	2.77	2.89	3.01	3.13	3.24	3.36	3.48	3.59	3.71	3.83	3.95	4.06	4.18	4.30	4.41	4.49	4.57	4.61	4.65	4.69	4.73	4.77	4.80	4.84	4.88	4.92
2.78	3.16	3.42	3.82	4.21	4.61	5.05	5.56	5.94	6.49	6.98	7.55	8.16	9.83	11.71	13.70	15.75	18.24	21.01	24.27	26.24	30.48	34.17	38.39	43.99	47.32	56.64	61.92	72.01	82.74	94.32	106.83	120.41	135.15	151.16	168.48	187.06	207.32	229.49	254.45	281.01	308.22	336.10	355.13	375.87	386.85	398.07	410.03	422.88	436.79	448.10	463.61	479.59	495.43
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Old 02-15-2010, 03:03 PM   #49
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I built a 72~ or so mm MAF draw through tube for my ATP 30r.. and it pegged out with the stock TMIC. That was with 28-30 psi with around zero degrees air.

In the summer with 60-70 degree intake temps it wouldn't go past 4.88 volts; I bet it's even worse now that I have a HUGE front mount. I'll be moving the MAF flange to a bigger tube (3.25 inch??) blow through here today when I borrow my buddys tig welder.. and we'll see what happens.
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Old 02-15-2010, 03:28 PM   #50
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Blow thru was very inconsistant on my car. Draw thru not only made more power but stayed consistant.
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