What lb/min are you flowing on pump & bigger turbos

[diambo4life]

The highest I have logged was 52-53lb/min (ported head + smim.) That was on race at 30psi on a nice cool day in the spring.

I trapped 126-127mph with 43-44lb/min at 27psi with some 22-23* timing in Feb. (stock head/stock 1G intake) The most I ever logged with the stock setup was around 47.

I am yet to make logs ever since the tempts went below 90*.

 

[Coup D E'Tat]

Totally forgot about the blow-thru guys.

Mike, were those airflow numbers on a calibrated MAF?

 

[90blacktsiawd]

What turbo are you running again Mike? fp3065? I would have thought the airflow would be higher than that at that kind of boost.

 

[tstkl]

I think he might have simply been joking at his small turbo, but I might be wrong. Either way, a boost leak after the mas will cause lower airflow numbers. The only thing that changes is when it is showing a lower number. With the stock system, if you have a boost leak in your upper intercooler pipe, you will see lower airflow numbers whenever you are out of boost and the motor is using vac to suck in the air it needs to run. This will cause it to run lean at these points. Just because up top when your boosting the airflow numbers are larger than normal, doesn't mean they are always such. This is why you can't tune properly with a boost leak. The airflow changes with rpm,tps, and boost, and an unpredictable rate. you might flow 300 hz at 5k rpms at -5 hg/in (the leak causes the number to be lower than normal due to the vac), as well as at 3k rpms with 3 lbs of boost (the airflow number is inflated by the leak here). Both examples have a condition of 300 hz being read, but neither of them is actually flowing 300 hz, nor are they flowing the same incorrect number. If the leak ALWAYS caused the number to be inflated or smaller than what it should be at a predictable rate, something as simple as an safc or a maft would solve your problem easily. Too bad this is not the case and boost leaks are spawns of the devil himself.


and just for the record, I now have BACK TO BACK proof (aka I just did it again today). A dsm, with a gm maf mounted on the uicp, with no pipe connecting the turbocharger to the throttle body (in my case I didn't have my licp, or my intercooler on) can run PERFECTLY FINE. Boost leaks before the maf do not cause drivability issuse, they simply cause the car to run slower than what it should be running at.

 

[Coup D E'Tat]

Yea, that's why I asked. At that boost level, 18* advance, and pump gas, I see ~50 lbs/min on an SC61, so his 3065 shouldn't be much different.

 

[NOSLO2PT0]

Yea, that's why I asked. At that boost level, 18* advance, and pump gas, I see ~50 lbs/min on an SC61, so his 3065 shouldn't be much different.

What kind of track times/whp you see with that? I can't imagine how you guys get away with that much timing on pump gas. I can't run more than 13-14* on 93 octane. You guys running 7.8:1 motors?

 

[diambo4life]

Totally forgot about the blow-thru guys.

Mike, were those airflow numbers on a calibrated MAF?

I guess..not very well callibrated depending on the time of the year. Sometimes it's dead on and sometimes it's way off. I just dont want to do it since I will not be able to compare logs I made a year ago. Although..I like assuming it's 4lb/min lower than what it should really be but honestly I dont care - as long as the car runs good at the track. Personally, I use the numbers relatively. For example...I know the car picked up 4-6lb/min from switching to a smim + ported head @ 30psi.

 

[diambo4life]

What turbo are you running again Mike? fp3065? I would have thought the airflow would be higher than that at that kind of boost.

Probably is quite abit higher. I know when I had the 2G MAS on there it read much higher but that was a long time ago....to me anyway. 65 it is. Should be going back to the track next month hopefully and making some 30psi+ runs. Better trap 130mph+ or I will drive it into a lake.

My car consistently picks up 30mph (or more) from the 1/8th. Very good top end. I am yet to trap over 97-98mph in the 1/8th though for some reason. Hope extra boost and some nice cold air puts it there.

 

[Coup D E'Tat]

Mike 2,

car hasn't seen the track or dyno yet. As some of you know, I keep blowing apart my VPE end tanks, and my new, much thicker, tanks are almost done. I was trying to wait until they were finished (so I wouldn't have to be worried about being stranded,) but I have a date with the dyno on Saturday, so I'm going to have to hope they hold together

Car should see the track within a few weeks. My tanks should be done within a week or two.

Edit : Yea, 7.8:1, stock '90 block.

 

[Kevin Jewer]

There are countless posts on the DSMlink forums that back up the airflow numbers. For example, dozens of different cars that all max out an EVO 16g at exactly 42 lbs/min, etc. I'm starting to gain a whole new appreciation for how well our MASs (or calibrated MAFTs) work now that I'm tuning the AEM on the EVO.

There are other ways to verify airflow numbers. Since we measure airflow in mass/time, and we can convert fuel flow from volume/time to mass/time if we know the specific gravity, a wideband O2 sensor can validate the numbers.

 

[donmagicjuan]

Boy, and I thought I liked math.

You have an excellent point though, Kevin. Sounds like something to do when I'm bored.

 

[Kevin Jewer]

I had a spreadsheet on my site that I have proven to within a fraction of a unit for AFR, FP, Airflow, IDC, etc. I took it down due to poeple passing it off as thier own. Takes all of the work out of it. It didn't take boredom to get me to figure it all out and make up the spreadsheet, it took a blown motor under conditions that all the "internet experts" said a 255 pump should be good for. Ended my career with the 2g before its time, but probably one of the meaningful and helpful post-mortems I've ever done.

 

[Black95TSIawd]

32lbs/min at 18psi on my b16g.

Correction!

35lbs/min at 19.5psi.

 

[Lurker]

I got 46.33 lbs/min at 19psi on my 2.3L stroker and PTE GT3251e turbo.
I am running non-hacked 2G MAF with the proper 2G MAF correction table in the ECU.

Lbs/min number was calculated just like 90awdtalon mentioned: log both the g/rev and RPM parameters, and multiply them together to get lbs/min.

 

[DSM90AWD]

Fiddy trim 45.5 lbs/min @ 21.5psi (mods in profile)

Turned up da wick on the fiddy to 23.5psi and am seeing 49-49.5lbs/min at 7.7K+

Still 11:1 AFRs, 16* max timing and 93octane WAWA (10% Ethanol Blend) and no knock to speak of. Guess my 7.8:1 stock pistons help some.

I'm sure a 2.3/2.4 would get more airflow, but has anyone seen more on a 2.0L with a 50-trim. Trying to gauge if it's time to move up as right now I'm solidly off the map

 

[andymoraitis]

I used Kevin's calculator (wow that thing is accurate) and ran the 50 trim to the point at which it runs out of fuel on 650's and starts to knock on an 11.5:1 tune (47.5 lbs/min) at around 27 psi. I think you see more airflow than I do at lower boost simply because of the SMIM and the fact that I'm running a stock 2G head and intake with a 2G TB. I'll be installing a 1G TB in a couple of weeks and I'll see what that does, but at 25 psi, she's running close to 45 lbs/min and pulling very well with a max shift point of 7200. I'll bet the aggressive nature of the intake cam advance is holding it back a wee bit as well.

A 30 psi run drops me straight into MAF overrun and clutch slipping territory, but it feels amazing. Time for a 2600, cam gears and some methanol.

 

[Kevin Jewer]

Turned up da wick on the fiddy to 23.5psi and am seeing 49-49.5lbs/min at 7.7K+

Still 11:1 AFRs, 16* max timing and 93octane WAWA (10% Ethanol Blend) and no knock to speak of. Guess my 7.8:1 stock pistons help some.

I'm sure a 2.3/2.4 would get more airflow, but has anyone seen more on a 2.0L with a 50-trim. Trying to gauge if it's time to move up as right now I'm solidly off the map

A 50 trim is going to max out right at 50 lbs/min on a good airflow sensor (non-calibrated maf trans####ers need not apply). Increasing the displacement will not increase the airflow, it will just lower the boost you achieve that airflow at.

 

[VETDRMS]

33lbs/min on my Evo III at 16lbs of boost.

 

[90blacktsiawd]

After fixing a few leaks i got 41.8 @ 22 psi. I'm jealous os dsm90awd

 

[sbcxtreme]

This thread is making me sick! I am only seeing 40lbs/min out of my pte bb57trim with fp2s! 24-25psi with water injection*washer fluid*. 22* peak timing. hmm, back to work with dsmlink i guess.

 

[ikickuintheball]

I've seen 43-44.5lb/min with my 50-trim with 22-23psi. I haven't logged 25psi yet (well I've tuned but hit F11 and forgot to save my logs).

Edit: did a pull today with 25psi and saw 46.9lb/min at 7.2k rpm.

 

[Kevin Jewer]

This thread is making me sick! I am only seeing 40lbs/min out of my pte bb57trim with fp2s! 24-25psi with water injection*washer fluid*. 22* peak timing. hmm, back to work with dsmlink i guess.

This is not unusual for not having cams. With cams you would expect to see 40 lbs/min at 20 psi, and ~47-48 at 25 psi, on a 2 liter. Without cams it takes 3-5 psi more boost to achieve those numbers.

 

[fwdeclipse]

This is not unusual for not having cams. With cams you would expect to see 40 lbs/min at 20 psi, and ~47-48 at 25 psi, on a 2 liter. Without cams it takes 3-5 psi more boost to achieve those numbers.

He has cams that is why he is pissed.

 

[Kevin Jewer]

Shit, I read that too fast and thought that the box the cams were in was for something else. I'm a loser. So that is officially ####ed. I would look for airflow metering inaccuracies, bad cam timing, etc. I would also be interested to know what it flows at 20 psi, and 15 psi (if it's possible to go that low).

 

[koho2731]

44.62lbs/min P&P 57 trim @ 23psi on 93 the rest of the mods in my profile. The airflow #'s are off due to hacked MAS and SAFC II. This is on a stock 2G 7 bolt.