Broke A Piston Wrist Pin.

[keltalon]

Keltalon, are you using a regular 2g MAF?

3"GM I am considering switching over to speed density!

 

[We're on Boost]

I'm using a 3" GM also, but my ecu+ translates the GM signal to 2g MAF HZ. My 1g DSMchips ecu is programmed to read 2g MAF Hz.
Anyway here's what I'm thinking about - My ecu+ that does the translation has a programmed-in MAF Hz limit of 4000 Hz. Tom Collins (ecu+ creator) says this was kind of arbitrary and he could re-progam it to go much higher. I've never asked him to do that but I'm wondering if I should. Someday he might forget how! I imagine that your ECMlink logs 2g MAF Hz for you after it translates the GM MAF signal? So what I'm wondering is, in your experience as your HP level has gone up and up, how much whp would you be getting at around 4000 2g MAF Hz?

 

[keltalon]

I'm using a 3" GM also, but my ecu+ translates the GM signal to 2g MAF HZ. My 1g DSMchips ecu is programmed to read 2g MAF Hz.
Anyway here's what I'm thinking about - My ecu+ that does the translation has a programmed-in MAF Hz limit of 4000 Hz. Tom Collins (ecu+ creator) says this was kind of arbitrary and he could re-progam it to go much higher. I've never asked him to do that but I'm wondering if I should. Someday he might forget how! I imagine that your ECMlink logs 2g MAF Hz for you after it translates the GM MAF signal? So what I'm wondering is, in your experience as your HP level has gone up and up, how much whp would you be getting at around 4000 2g MAF Hz?

Good question. the 573whp I made my dsmlink was reading 2700hz I would assume that at 4000hz I would max out around 800 or so. here is a copy from the ecm page on mas limitations.

Basic MAF data

Here is some basic information for the MAF sensors used in the DSM world.
Mitsubishi MAF senors

Mitsubishi MAF sensors operate by measuring pressure, temperature and volume. The ECU takes that data and multiplies it out to calculate air mass. Air mass is then used to calculate fuel mass required to achieve a 14.7:1 A/F ratio. That fuel mass is then used (along with the ECU's idea of which injectors are installed on the car) to calculate injector pulsewidth. And then THAT is finally used to schedule the injector firing events.

But it all starts with airflow measurement. Like all devices, Mitsubishi MAF sensors were designed to operate in some pre-defined range of operating conditions. One of those, of course, is the volume of air flowing through the MAF sensor. When the true volume exceeds the measuring capacity of a Mitsubishi MAF sensor, you end up with an erratic volumetric output. The erratic output feeds into the fuel calculation described above to produce an erratic A/F mixture. And that produces erratic engine operation, typically while you're running wide open throttle!

Mitsubishi MAF sensors report volumetric data using a frequency. You can log this in ECMLink as MAFRaw. You can monitor this frequency to determine how closely you're running to the known limits of that MAF.
1G DSM MAS

A stock, unhacked 1G DSM MAS will not accurately report frequencies above 2000hz. That frequency represents roughly 180 lps (380 cfm) of volumetric airflow. At standard temperature (around 77F) and sealevel pressure, that's about 210 gm/sec (28 lb/min) of mass airflow.
2G DSM MAS

A stock, unhacked 2G DSM MAS (same as the 3000GT VR4 MAS, same as an Lancer EVO1-3 MAS) was designed to operate a bit higher. You'd expect overflow on a 2G DSM MAS around 2700hz. That frequency represents roughly 320 lps (about 680 cfm) of volumetric airflow. At standard temperature (around 77F) and sealevel pressure, that's about 375 gm/sec (50 lb/min) of mass airflow.
EVO8 MAS

A stock, unhacked EVO8 MAS (effectively the same as the 3G Eclipse MAS) was designed to operate even higher! You'd expect overflow on EVO8 MAS around 3000hz (we think…I'm not sure I've actually seen an EVO8 MAS overrun). That frequency represents roughly 420 lps (about 890 cfm) of volumetric airflow. At standard temperature (around 77F) and sealevel pressure, that's about 500 gm/sec (66 lb/min) of mass airflow.
Summary
MAS Freq limit Volumetric limit Mass limit
1G DSM 2000hz 180 lps (380 cfm) 210 gm/sec (28 lb/min)
2G DSM 2700hz 320 lps (680 cfm) 375 gm/sec (50 lb/min)
EVO8 3000hz 420 lps (890 cfm) 500 gm/sec (66 lb/min)

When running one of these MAF sensors anywhere near these limits, use ECMLink's MAFClamp function. Read the help files and forums for more information. By using this function properly, you can effectively remove the upper airflow limitation of these MAF sensors. Even so, it's highly recommended that the 1G DSM MAF not be used simply because its limit is too low to produce reliable MAFClamp operation when running substantially more airflow than the sensor was designed to meter.
GM MAF sensors

The two most common GM MAF sensors used on our DSMs are the 3” and 3.5”, part numbers 25180303 and 25179711, respectively. These sensors operate fundamentally different than the Mitsubishi MAF sensors. The GM MAF sensors work by measuring mass airflow directly. They do not need temperature and baro data because they're not measuring volume. They are reporting air mass directly as a frequency.

The biggest problem, IMO, with these MAF sensors is that this frequency to mass mapping is non-linear. So as airflow increases, it takes less and less change in frequency to present a larger and larger change in air mass. This makes the system very sensitive to fluctuations in frequency output from the sensor.

Neither a MAF Translator nor the ECMLink V3 GM MAF cable allow you to see the raw GM MAF sensor frequency directly. The MAF Translator provides a translation to stock DSM-like frequencies, while the ECMLink V3 GM MAF cable provides a simpler translation that produces raw frequencies that are quite different (but that the ECMLink V3 ECU code knows how to handle). So it's best to avoid talking about limiting-frequencies when discussing a GM MAF sensor when used on a DSM and rather just talk about air-mass metering capability.

Also, the GM MAF sensors, like any MAF sensor, are sensitive to anything that causes the airflow through the sensor to be unevenly distributed across the entire area of the sensor opening. It's very common to see smaller diameter piping leading to or from a GM MAF sensor cause the sensor to produce a higher airflow reading than that actual mass of air flowing through the sensor. Because the metering capability of the sensor is dictated by the maximum airflow reading it can report, having it report a value that is artificially high reduces the metering capability of the system.

That said, you can expect a 3” GM MAF to easily measure (report) 600 gm/sec (80 lb/min) well before any “limit” is reached. The 3.5” would probably measure over 700 gm/sec (92 lb/min)! The problem is that we have very little data to back any of this up. But the bigger problem, again, is that well before you reach these limits, the frequency to airflow mapping will simply become too sensitive to be usable. The result is a very choppy airflow signal to the ECU and many of the same problems mentioned above with MAF overrun on a Mitsubishi MAF. It's just for a different reason.

So with that in mind, we typically recommend that ECMLink users enable the MAF Clamp function with running a GM MAF. Enable it around, say, a MAFRaw reading of 2700-3000hz (that might vary a bit depending on whether you are using a MAF Translator or an ECMLink V3 GM MAF cable) so that the MAF signal is effectively ignored above that frequency anyway and it won't matter what's going on with the signal. This also effectively removes any metering limit that might have existed"

 

[We're on Boost]

Good question. the 573whp I made my dsmlink was reading 2700hz 2G DSM MAS ...

The biggest problem, IMO, with these MAF sensors is that this frequency to mass mapping is non-linear. So as airflow increases, it takes less and less change in frequency to present a larger and larger change in air mass.

Ok that's good news. Sounds like 4000 of them little Hz critters is more than I'll ever need. I'm glad that Jeff Oberholzer suggested to me to convert the 1g ecu over to reading 2g MAF Hz.

I had been linearly extrapolating from where I'm at now, and thinking that 4000 Hz might not get me to 500 whp. Guess that is way off! So the idea that this is actually non-linear was news to me. Thanks for all the good info!

On the subject of the even distribution of airflow through the GM MAF, I guess I could ask you another question about your setup there: Is your GM MAF in blow through? If so, are you using a 2.5" diameter intercooler pipe that flares out to 3.125" just before the MAF?

 

[keltalon]

Ok that's good news.
Is your GM MAF in blow through? If so, are you using a 2.5" diameter intercooler pipe that flares out to 3.125" just before the MAF?

Yes its in blow through mode flaring out from a 2.5 intercooler pipe to the 3 1/4 gm mas just before and returning to 2.5 pipe after the sensor.

 

[jmartinez1228]

Same setup I had as well, actually have my 3" gm mass w/ couplers for sale if anyone is interested.

 

[keltalon]

<iframe width="480" height="360" src="http://www.youtube.com/embed/dWjTERuyh5w" frameborder="0" allowfullscreen></iframe>Okay I guys ups came today a dropped off some more goodies. I purchased some more items from Brian crower this week. First off both items are newly designed and I must say they must be making some money these days because the quality that they are putting into their stuff is unbelievable wow. They have a new set of cam gears that is what I have been looking for. They are doweled for evo use as well as 1g 2g use. I am more impressed with the fact that they are now using arp locking bolts. Another thing is they now are putting top dead center alignment marks on the gears no more guessing. I am pleased with the purchase. Here are some pictures.

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[keltalon]

Now as for the cams. I was going to start my car off with the bc272s I am now going to install these new stage 4 came from bc. The new stage 4 have a less lift and more duration than the old 288 cams. The new cam have some of the exact same specs as he kelford 280s they are now 284 280 should prove to be better for valve train. Here are some pictures.

 

[keltalon]

Camcard

 

[keltalon]

Cam gears and cams installed held with jay racing timing tool

 

[1glaserfwd]

What was the price on those cam gears? They look amazing!!

 

[keltalon]

Well it look like the thread has turned into a build journal

 

[keltalon]

here are the cam both cam cards for comparison between the old and new stage four cams.

 

[jmartinez1228]

Reggae in the backround
So relaxing and brings back the good old days for me.

 

[keltalon]

Reggae in the backround
So relaxing and brings back the good old days for me.

Man what you know about that

 

[jmartinez1228]

Man what you know about that

Puerto roc who grew up in the north end of hartford, ct my friend. Which is predominantly afro american + jamaicans. P. Tosh, steel pulse, the police (white reggae group ) and of course the great one bob marley. Records my uncle used to play. Like I said man it was good times growing up. It will never be like that again.

 

[keltalon]

Puerto roc who grew up in the north end of hartford, ct my friend. Which is predominantly afro american + jamaicans. P. Tosh, steel pulse, the police (white reggae group ) and of course the great one bob marley. Records my uncle used to play. Like I said man it was good times growing up. It will never be like that again.

Wow! Well my pops is from the island.

 

[jmartinez1228]

Wow! Well my pops is from the island.

Well of course you got me beat my wife laughs at me when I talk to a jamaican because she can never understand what they say.

Anyways those BC camgears look good. I just got a set of hks 272s and was looking for some fidanza or hks cam gears. These might just have to take their place.

 

[hotrodssnova]

4 bolts, holding things in time? are the center parts pretty beefy?....By beefy, I mean thick. that is a big engineering change to toss out a couple of bolts. do they weigh less or more? man, sorry for the questions, seems important.... say an 8000 rpm blast and have to push the clutch in to stop, that extra mass could shift some stuff around.....change timing(bolts move), more mass means more stress on belt, possibly crank gear keyway?
just askin your opinion

 

[keltalon]

4 bolts, holding things in time? are the center parts pretty beefy?....By beefy, I mean thick. that is a big engineering change to toss out a couple of bolts. do they weigh less or more? man, sorry for the questions, seems important.... say an 8000 rpm blast and have to push the clutch in to stop, that extra mass could shift some stuff around.....change timing(bolts move), more mass means more stress on belt, possibly crank gear keyway?
just askin your opinion

yeah they are very beefy. I locked them down today they snugged pretty well. I will put them on the gram scale tomorrow and post exact weight. they for sure are lighter than stock gears. I will weigh all three tomorrow. I don't mind about the questions its all good. LOl

 

[keltalon]

Okay I polished my compressor housing this morning took about an hour. Pictures are in steps I will post a video later.

 

[keltalon]

Another shot

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[dragonov_elite]

I have always wanted to try a Comp turbo out but they just do not seem to have anything with a Twin scroll T3 foot print.

Cam gears look good. I own the AEM gears and your gears look a bit more beefy than the AEM gears. Glad to see they finally changed the degree marks on them.

 

[keltalon]

I have always wanted to try a Comp turbo out but they just do not seem to have anything with a Twin scroll T3 foot print.

Cam gears look good. I own the AEM gears and your gears look a bit more beefy than the AEM gears. Glad to see they finally changed the degree marks on them.

Have you call them about a custom setup. They have sooo much more stuff that's not even mention or seen on their website. Ask to speak to justin he is the turbo Guru!

 

[keltalon]

4 bolts, holding things in time? are the center parts pretty beefy?....By beefy, I mean thick. that is a big engineering change to toss out a couple of bolts. do they weigh less or more? man, sorry for the questions, seems important.... say an 8000 rpm blast and have to push the clutch in to stop, that extra mass could shift some stuff around.....change timing(bolts move), more mass means more stress on belt, possibly crank gear keyway?
just askin your opinion

Here you go


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