Tuning?

SlowWhite · 01-15-2006

Ok just went for a ride and noticed something on my logs. Even at 30psi my lbs/min still are at 53lbs/min. So what's up? that's the same lbs/min I was seeing at 22psi.

But when I first started out on 23psi I noticed my lbs/min were 55lbs/min?

**Shane@DBPerformance** · 01-15-2006

Maybe you maxed the MAS?

niterydr · 01-15-2006

I would also bet you were pinning the MAS. How many Hertz of airflow are you seeing? I think the 2g one can read up to 2800hz ? I'll have to go look it up.

**1ViciousGSX** · 01-15-2006

GM MAFT it.

**scheides** · 01-15-2006

Yup, time for a MAF, unless you wanna do MAP w/ EMS.

SlowWhite · 01-15-2006

That's sucks. For now till I move back I'll probably just keep pushing it on Pump Gas. And then go to MAF or EMS later.

Hopefully I'll be able to get a little bit better of a tune going should still be able to make more power even if I won't be able to up the boost to where I wanted it.

**Shane@DBPerformance** · 01-15-2006

You could start hacking the 2G MAF and using the MAF compensation table in DSMLink or just clamp the MAF and start using the VE table in DSMLink.

**Goat Blower** · 01-15-2006

You need a PMS.

SlowWhite · 01-16-2006

Well Not sure exactly if this was the problem but today I took the car to work, and everywhere that entailed. and no matter what I did the stuttering never stopped.

Well right as I was on my way home about 1/2 block from my driveway I got on it to pass a car and My downpipe coupler fell off. Not sure if that was the problem the entire time but I did lower my boost back down to 25psi which I'd been running on pump gas for ever. And still had the same problems. Plus I was noticing that my boost was coming on later.

I found the coupler (went home and jumped in the concorde with Jenny) and it only had minor scratch's on it from bouncing down the road at 45mph. I got lucky it bounced into the divider. so it didn't get run over.

Anyrated I'll start to put logs up hopefully later tonight for you guys to review.

The most boost I was hitting was 32psi and it was always fine till about 6000RPMS (which is just about when the boost was coming on really strong (typically I'm at full boost/spool by 5800rpms)

**1ViciousGSX** · 01-16-2006

You probalby just found your air flow problem.

SlowWhite · 01-16-2006

I"m hoping that's the case, they are having another Midnight madness again at Moroso this Friday. 6-2am. Temps in the evenings have been in the low 40's high 30's(during the day it's been in the low 70's) lately so hopefully it'll be a nice cool night. (and I'm going to compete in the brackets that way I get in line with the full out drag/rail cars so the track will hopefully be extra sticky.

**Shane@DBPerformance** · 01-16-2006

Do you have a wideband on it? If it isn't "seeing" anymore airflow at 30psi than it is at 23psi, then it isn't going to add fuel for all that extra boost.

SlowWhite · 01-16-2006

I'll review the logs but I don't think it ever got above 55lbs/min. Typically at 25psi I normally see 53lbs.min And all day that is about what I was seeing, But I rarely got to do a pull over 6200rpms it would start to buck and sputter, so I always backed off the gas. Accouple times I got to about 7000rpms but it was getting pretty bad. I'll have the downpipe back together shortly and then I'll take it back out to see if anything changed.

Honestly I'm really leaning towards the downpipe being my problem (at least at this point) I was running 25psi on pump gas before with no problems at 53lbs/min. Even when I started running race gas at the same PSI I wasn't having this problem. This was my first time taking the car out since I reinstalled my turbo/exhaust manifold with new gaskets. Obviously did not get the clamp on 100%

TheBlizzard · 01-16-2006

How is the downpipe going to cause bucking and sputtering at that high of RPM? Sounds to me like you have other issues Brian, like running lean.

EclipseGST · 01-16-2006

Well going by him saying he lost a coupler, I think he might be talking about the lower intercooler pipe? Just a thought, I dont know.

TheBlizzard · 01-17-2006

I thought he meant his V band clamp came loose on his downpipe.

SlowWhite · 01-17-2006

It was the V-clamp to the downpipe. My 02 sensor is connected to the downpipe not the o2 housing. But then again for the most part the downpipe was connected so it still should have been running fine.

I don't see why things all of a sudden changed, Last time at the track I was running 116oct still running 25-26psi. (cause I thought the EGT's where supposed to go down with race gas) Anyrate The car was running totally fine. I was running 12.0-12.1@116.9mph but pulling 1.9-2.0 60's. Anyrate On the last run I'd upped the boost to 28psi and on that run my turbo-exhaust manifold bolts came loose and I blew the gasket. (was running fine for 1and2 gear, went out in 3rd)

Since then I unbolted the turbo and took off the exhaust manifold that way I could install the 4th bolt for the turbo-exhaust manifold. (prior I was only running 3 bolts which I'm pretty sure is why the other bolts kept coming loose)

Anyrate After that I installed the 18.5lb radiator cap, and the sealed Coolant overflow, blew the alternator fuse, and had to replace my battery.

That's all I changed. I'll take the car out to Bee-Line Hwy hopefully tonight to do some tuning. And we'll see if the downpipe changed anything. I'm hoping that the downpipe being off slightly was causing the 02 sensor to mis-read the air.

But like I said I've turned the boost back down to 25psi which has been trouble free since I installed the motor, and I'll re-load my settings from when I ran my 11.7 and start from there. (Before I go though I'll do a boost leak test to see if my coupler is leaking (the one from the turbo to the FMIC has been giving me problems for sometime so that might be apart of it)

TheBlizzard · 01-17-2006

I forgot you O2 sensor was in your downpipe and not the O2 housing. I guess it could have been the problem, but unless it was totally just hanging there and not connected at all it should have been giving a reading even if it was leaking. I guess see how it acts tonight and go from there.

SlowWhite · 01-17-2006

I did a boost leak test and nothing, except the usual place (SMI came with a small pin sized hole in one of the welds on the #1 runner)

Anyrate It's supposed to rain so we'll see what happens. Worste case senario I go back to pump gas with out ever getting to do a run on Race gas and higher PSI.

I'll be racing on Friday assuming the sputtering is gone. I also have to check the spark plugs. They are brand new with less then 25 miles on them but still.

tim · 01-17-2006

Quote:

Originally Posted by TheBlizzard

I forgot you O2 sensor was in your downpipe and not the O2 housing. I guess it could have been the problem, but unless it was totally just hanging there and not connected at all it should have been giving a reading even if it was leaking. I guess see how it acts tonight and go from there.

Even a slight leak before the O2 sensor would cause a false reading. All that air flowing by would be sucking more in from the outside. I had a similar problem on a completely different vehicle where the there was a leak before the O2 sensor and it caused some very poor driveability. I am not saying that is is for sure the problem but even the slightest exhaust leak before the O2 sensor can and probably will cause problems.