Airflow vs. PSI - Big turbo @ 24psi - car is still slow

[zdrux]

I`m currently running the AGP L2R and I think it's time to get a new turbo. I've been recently reading some threads and finding things that I couldn't believe. My car has been slow ever since the motor was built 6-8 months ago. I've done leak tests (numerous times) which turned up a few leaks here and there and they were fixed. Lastly, I changed my 1G TB to a 2G because the 1G had a leak at the throttle-cable shaft, and now the whole system holds 25psi+

Now after some reading, I see people putting down 300whp+ with much smaller turbo's than mine so I wondered what the hell was up. After some logging with DSMLink it looks like my airflow lbs/min are lower than everyone else's. People seem to get 38-40lbs of air with 18-20psi, meanwhile I cannot get more than 39lbs/min with 24psi !!!

Can anyone recommend what the hell the problem could be? Could the turbo REALLY flow this horribly bad?! I have cams 272's regrinds but I doubt that would be a problem (with degre'eing cams).

Can anyone tell me what would be limiting my airflow so low? Would getting a new turbo help in this? Something that flows ALOT better at 24psi than just 39lbs?! Does anybody else here experienced such low airflow with their setup? I`m leaning towards the AGP 50trim, or a GT30R turbo, would these change my airflow? My car feels like it's putting down MAYBE 250whp, and it just feels slow for this size of turbo (I believe it's a 57trim?)

I wouldnt mind getting some response from people with their airflow readings and the psi they were at when they got that airflow reading.

Here's a list of my mods:
6bolt swap (97 2G)
9:1 Forged Wiseco / Eagle combo
272/272 regrinds
AGP L2R Turbo
FMIC
FIC 850cc injectors
DSMLink for tuning

Thanks alot guys.

EDIT: Perhaps this would make more sense in the tuning section? Perhaps a MOD can move it there. Thanks.

 

[DSMvroom]

you have dsmlink; y not take it to the dyno for some tuning? i'll bet you'll find lots of answers working with "pros."

you don't even know what you are throwing down. You also make no mention, or have no information on a 1/4mi time. Basically you have a bunch of stuff with no knowledge, except that it is "slow."

edit: btw, 39lbs is alot. gg

 

[1993eclipseGS]

Take the car and get it dyno tuned.

 

[destruckeclipse]

His profile says it has more. I agree it's time to hit the dyno and get some real tuning done.

Bar & Plate 32x12x2.5 FMIC 850cc FIC Injectors DSMLink ACT 2600 clutch w/street disc AGP L2R BallBearing Turbo Full 3" exhaust with hi-flo cat Walbro 255 HKS VPC HKS Turbo Timer Tial external wastegate Westach EGT gauge SPI boost gauge Short throw shifter Aeromotive AFPR

 

[RedTurboEclipse]

just for your reference.. i have a stock 7 bolt.. with dsmlink, pte 50.. all supporting mods.. the most lbs/min i saw was 34.. at what dsmlink says at estimated 18 psi.. although my autometer was reading 20.. thomas @ dsmlink said might be inaccurate boost gauge.. i shouldnt worry.. if it was the other way around.. and estimated is higher than measured.. then its prob. a boost leak..

anyways this was with the stock preset based on what i told them.. (denso 660s, no cas, hacked maf) i did no adjustments

 

[4G63 For Me]

Wow, the similiarities of our situations are scary. I only hit around 39lbs of airflow at around 24 PSI (I think it drops off to around 20) and I don't have a small turbo.

I do have something on you though, a slow ass timeslip to backup my car's slowness. I ran a 13.7 @ 101MPH. I beat all the Transams and Mustangs that were there, but that is still REALLY slow. I should be in the 12's at MOST. If you ever get this problem figured out, send me a Private Message or something, and I will do likewise. Goodluck!!

 

[zdrux]

the most lbs/min i saw was 34.. at what dsmlink says at estimated 18 psi..

This seems a little bit encouraging to me, thanks for your log.

As for the other responses, much appreciated, although I`m pretty confident in my tuning abilities, the car feels somewhat the same as it did when I had my 18G at 20psi, that's why it is a little puzzling to me. Everywhere I've read about the L2R - everyone swears by it, but only on reace gas and at pressures 25psi+ which I`m not ready to run on the street.

I think I`ll be buying a 50trim anyway, as it seems to be "the thing" for dsm's as far as pump gas goes. My turbo doesn't hit 24psi untill about 4.7k or 4.7k in 3rd gear, so it's a little slow-spooling because of it's compressor size, this could probably be another thing adding to my "slow car" idealism.

And like destruckeclipse said, yes - my car/motor is pretty much built all around, I only listed the mods that I thought would be relevant to this problem at hand.

 

[staticbrainwash]

what about exhaust work, which ill assume you've done.

not to mention any head work or intake manny. those 2 spots can really bottle neck flow.

 

[zdrux]

what about exhaust work, which ill assume you've done.

not to mention any head work or intake manny. those 2 spots can really bottle neck flow.

The head is a stock unported 1G head, but I doubt this is the limiting factor here. The exhaust is a 3" with a high-flo cat, BUT I've got a stock ported 2G O2 housing which is the only thing that could *possibly* cause some flow restrictions. I can see the o2 housing increasing lag, but once it gets to 24psi, it should be moving alot of air.

The only reason for this, is I see the turbo really sucks at these low(er) psi levels. When the turbo is set at 16 - 18 - 20psi, there really is a SMALL differtence in power, but once you set the boost to 24psi, it really starts hauling, which leads me to believe this is where its just starting to flow some good numbers, unlike a 20G or a 50trim which flow much better at lower psi. Someone correct me if I`m wrong

 

[gixrman]

Have you tried to see pressure drop along your system? i.e. whats your psi at your compressor outlet? After intercooler? at the TB? Your turbo may be working really hard to push air thats going nowhere.

 

[4wd-Eclipse]

zdrux have you tried to post your problem in DSMLink forums? if NOT you should do it and attached some logs with it

 

[Mellon]

what are you sucking the air in through?

small MAS/MAF/AirFilter?

wondering if it's an inlet restriction

 

[RedTurboEclipse]

Yes, you might also want to post your issue in the DSMLink members only forum..

You can find my log there as well.

 

[CanadianTSi]

Considering your spooling 1000 rpms later than you should be I think you've got some problems, either a bad tune, a bad turbo, or a bad motor. How is your compression BTW??

 

[EclipseOwner95]

I'm running dsmlink with a SCM50 and all the supporting mods and FP2 cams and I see about 44-45lb/min on it. In order for it to show the correct lb/min you have to have several parameters setup up correctly which I can't name off the top of my head, my friend has the same setup as mine and dsmlink was showing 60lb/min of airflow because some of the parameters were off, have it tuned, should fix all your problems.

 

[zdrux]

I'm running dsmlink with a SCM50 and all the supporting mods and FP2 cams and I see about 44-45lb/min on it. In order for it to show the correct lb/min you have to have several parameters setup up correctly which I can't name off the top of my head, my friend has the same setup as mine and dsmlink was showing 60lb/min of airflow because some of the parameters were off, have it tuned, should fix all your problems.

There's no "paramaters" to set in DSMLink besides the car weight, FWD/AWD, wheel-size, and something else, and all these are used only for DSMLink's "HP Calculation". Why would someone put it a field that changes your airflow reading?! That's absolutely opposite of what DSMLink is supposed to do.

I`m running a stock untouched 2G MAS with your typical 3" cone filter. Past that, I really don't know why you are pulling in so much air vs. me with a similiar setup? Do you have anything that's considerably different than my setup, just so I can compare?

Also, after pressure testing the system, the bleed-off rate I think is about 1psi per 2-3seconds, I don't think this is too much? It seems pretty normal to me.

 

[EclipseOwner95]

Not actual " parameters " but theres what like corrected air flow, maf switch over, and all off that has affect on the lb/min reading, theres a way to set it, you get on the graph, and have 3 parameters logged, and there all supposed to be about dead on.

 

[nanokpsi]

Not actual " parameters " but theres what like corrected air flow, maf switch over, and all off that has affect on the lb/min reading, theres a way to set it, you get on the graph, and have 3 parameters logged, and there all supposed to be about dead on.

The only thing that will have an effect on airflow is if you alter the stock airflow tables. If you are running a stock mass, there is no need to mess with any of those anyways, especially if you are flowing less than 47 lb/min.

Typically, a 1g set up will flow about 40lb/min at 20psi with cams. The biggest impact on airflow otherwise is going to be your intake temps. What are the intake temps in the logs were you are seeing this airflow? Other than that I will might have to put some impact on the regrinds just becasue there isn't anything else to put it on. Maybe the o2 housing and cat will hurt it a little as well.

38-39lb/min is over 300WHp if it is tuned well, and that is with pump gas. Tuned with c16 at that airflow level and it should be around 340-350whp.

 

[zdrux]

Hmm, I will do a log and see what the intake air temp is. Also just to throw it in, if I advance my CAS just a touch higher than where it should be, I get intake explosions.

Not ignition explosion out the intake, but the air rushes back out and always blows off a vacuum hose off of the intake manifold, so I can't even advance my timing a little higher if I wanted to. This leads me to believe that my regrinds have some valve overlap, where the intake cam is closing later than it should, allowing alot of air to escape before the intake valve is fully closed, blowing my lines off. Has anybody else experienced this, or heard of this happening?

 

[zdrux]

Ok I went out and did some more driving this evening. After looking at my logs, things looked a little fishy. For example if I advance my CAS a bit, the timing would actually max out at about 12 degrees all the way to redline, made the car feel like sh!t. Another thing, was when I would retard timing in dsmlink, my fule at that RPM actually got leaner.. so ofcourse I said "What in the ..."

So I went out and flipped my CAS 180 degrees, and to my surprise the timing curve was actually streight for once, not jaggy like someone's lifeline. My fuel was actually all there and not running lean with 850cc's like I was before.

But the best part is, I managed to pull in about 36-37lbs of air with only 20-21psi !! From this I will only assume the CAS was put in wrong at the time of the build. I *DID* try flipping it around before, but I think I was simply un-tuned for it to really make any difference so I put it back (the wrong way).

Now, this alone doesn't solve my dillema of why people can 40lbs at 20psi, but it certainly is a step forward. For all those watching this thread and having similiar problems, it's definately something you can try and see if it helps you too a bit.

 

[diambo4life]

Now, this alone doesn't solve my dillema of why people can 40lbs at 20psi,

You do not have cams! You are not going to see 40lbs/min at 20psi without them, and I didn't hear a wideband being mentioned anywhere? How do you tune without one?

 

[zdrux]

I have 272's HKS re-grinds non-degreed. I`m only using DSMLink on the street to tune, I might be off by maybe 50horses if I were to go to the dyno, but I`m only looking to solve this problem and not squeeze every last bit out of my car and so far I`m making progress.

Keep in mind, my tuning began at about 105F weather (thats about 40C for us in Canada here). The actual weather outside was about 77-86F, but I`m guessing the intake temp(s) are a bit higher because of the under-the-hood element. The temps got considerably lower as the night progressed, and my results got higher. The car pulled harder and harder the later it got.

 

[unior]

Wow, the similiarities of our situations are scary. I only hit around 39lbs of airflow at around 24 PSI (I think it drops off to around 20) and I don't have a small turbo.

I do have something on you though, a slow ass timeslip to backup my car's slowness. I ran a 13.7 @ 101MPH. I beat all the Transams and Mustangs that were there, but that is still REALLY slow. I should be in the 12's at MOST. If you ever get this problem figured out, send me a Private Message or something, and I will do likewise. Goodluck!!

wow i ran better times with $40 in mods

 

[4G63 For Me]

wow i ran better times with $40 in mods

Yeah, I ran some bad times. But 13.7 up here isn't the same as 13.7 down where you are. To put it in perspective a bit more, there was a Viper there running 13's as well.

Assuming you ran the 13.6 with the current mods in your profile...

"ported 2g exhaust manifold, ported 7cm turbine housing, ported 2g o2 housing, hacked maf, act 2600 street"

Let me know where I can get an ACT 2600 for $40.

 

[unior]

Yeah, I ran some bad times. But 13.7 up here isn't the same as 13.7 down where you are. To put it in perspective a bit more, there was a Viper there running 13's as well.

Assuming you ran the 13.6 with the current mods in your profile...

"ported 2g exhaust manifold, ported 7cm turbine housing, ported 2g o2 housing, hacked maf, act 2600 street"

Let me know where I can get an ACT 2600 for $40.

Nah the only mods at the time was a ported 2g ex mani, everything else was free, stock clutch, stock o2, stock 6cm turbine housing, maf was hacked, exhaust dropped, vacuum line pinched to get me more boost - no idea how much boost since i wasn't running a boost gauge

i will give you the elevation i raced at ~300' above sea level