WTF am i doing wrong here. should be 12's

[cfisher]

Okay. Checked my base timing with a timing light and it's fine. Went and reset the ECU. Drove around for about 2 hours and got my lows tuned. Put my highs on -20, -22, -28, -32, -34, -32, -32 with throttle points at 30/80. Gotta say it pulled alot smoother and felt stronger than it ever has. Normally when I richened it up this much it ran like crap so I'm assuming it's because I reset my ECU this time. Didn't even get a chance to log it yet but I could just tell it was better. My idle sucks though. It doesn't surge but whenever I put it in neutral it drops to 500RPM's or so for about 5 sec and then bounces back up to 800 where I set it. Also pulled a CEL for o2 heater circuit malfunction. Is my o2 sensor on it's last leg and that's my problem?

 

[94awdcoupe]

Do yourself a favor before you go any further. Check your compression. How many miles are on the motor and are you still on the 7 bolt?

 

[cfisher]

I have not checked the compression but I just broke 70K on the motor and it's the stock 7 Bolt. I know, crankwalk but I really dont' think that's it.

 

[anconover]

Compression could cause a lack in power, but shouldnt mess his tuning up like it is. You said you base timing was fine? Whats fine? The smallest changes make the largest difference. My friend was doing 13.8's all day long, i advanced the timing a little, leaned it out a few % on the s-afc, dropped to low low 13's with a still poor tune.

My friend ran a 14.1@9x and that was with just a 2.5" exhaust, and a boost controller. Your tuning is way off somewhere, or ur motor is wooped.

 

[BluemeanieTSi]

if it's a 2g and his base timing "wasn't" fine.... tell him to fix it

what's your timing like when driving.

 

[BluemeanieTSi]

what were your EGT's???? If you are still under 1500F you still have more room to lean her out. With 25 psi, 94 octane and 24 degrees advance seems that you are way too rich. Try taking out some fuel and see where your timing goes. If it goes down then you will start making power. The timing advance you should tune for is roughly 15-17. I made more power with 14-16 rather than 19-20 plus timing advance. Make sure when you start leaning her out, see if the EGT's change. 1650f should be you max.

i never trusted my egt gauge since it would say 1800 at anything over 12lbs on a 14b. i know i was running rich but all i had was the translator 5% more lean was too much.

 

[td06hkiko]

if it's a 2g and his base timing "wasn't" fine.... tell him to fix it

what's your timing like when driving.

My timing at cruising is 32 deg.

 

[td06hkiko]

Okay. Checked my base timing with a timing light and it's fine. Went and reset the ECU. Drove around for about 2 hours and got my lows tuned. Put my highs on -20, -22, -28, -32, -34, -32, -32 with throttle points at 30/80. Gotta say it pulled alot smoother and felt stronger than it ever has. Normally when I richened it up this much it ran like crap so I'm assuming it's because I reset my ECU this time. Didn't even get a chance to log it yet but I could just tell it was better. My idle sucks though. It doesn't surge but whenever I put it in neutral it drops to 500RPM's or so for about 5 sec and then bounces back up to 800 where I set it. Also pulled a CEL for o2 heater circuit malfunction. Is my o2 sensor on it's last leg and that's my problem?

How much boost are you running, what are your EGT temps and timing like?

 

[4G63dsmpwr]

I'd like to know more about the accuracy of the EGT guage.

I just purchased one, and hope I didn't waste my money!

You mentioned it reading over 1800 degrees, anything over 12lbs w/the 14b?

Any info is appreciated!

 

[Mellon]

first thing I would do is a compression test becasue if you're blowing massive amounts of boost past the rings your turbos are working their ass off to keep up with whatever boost setting you're running. Overspinning the turbos gets them way out of their efficiency range and only serves to throw air hotter than the 7th layer of hell into the car which in turn sets of knock at moderate boost levels.

if the compression checks out and your intake pressure test is excellent (good isn't good enough) then I would experiment.

lower the boost to wastegate pressure
tune for 11.5 to 11.7 on pump gas and the timing should be good.. if it is add boost until you see timing take a dive. If timing dives make sure your a/f is still 11.5 to 11.7 and if it did stay there turn the boost back down until timing isn't interrupted.

 

[1LE]

Why exactly does it matter to the turbo if the boost is leaking out through a hose leak, past the rings, or just venting out the wastegate? Why would you end up with hotter air running at let's say "14psi" due to a small boost leak vs. 14psi controlled by the wastegate?

 

[Mellon]

Why exactly does it matter to the turbo if the boost is leaking out through a hose leak, past the rings, or just venting out the wastegate? Why would you end up with hotter air running at let's say "14psi" due to a small boost leak vs. 14psi controlled by the wastegate?

because your turbos are having to work harder to get up to that 14psi since some boost is escaping out a hose or rings. so your turbos might be doing the work required for 20psi just to maintain 14psi.

the wastegate doesn't open until 14psi and only then does it dump, so it's not like it's constantly leaking like a boost leak would be.

 

[1LE]

because your turbos are having to work harder to get up to that 14psi since some boost is escaping out a hose or rings. so your turbos might be doing the work required for 20psi just to maintain 14psi.

the wastegate doesn't open until 14psi and only then does it dump, so it's not like it's constantly leaking like a boost leak would be.

I still don't follow why it matters that you are at 14psi because of the wastegate venting, or a boost leak. You're still venting the same thing, just a different place.

If you have a leak AND the wastegate is set to 14psi, I can see increased lag as you were losing boost during the time at which it was spooling up, but once you hit the point at which the wastegate opens, you're dumping air out of 2 different places to achieve the same boost.

I guess, in summary, I don't see why dumping it out the wastegate is "less work" than dumping it out anywhere else. Either way, I'd think the turbo is spinning and compressing (working) at a rate determined by it's design and the speed/density of the exhaust flow. Obviously, if the pressure is higher, thermodynamics dictates that the temp will increase with the compression, but if the pressure is bleeding off, why is bleeding at the wastegate better than anywhere else? Pressure is not maintained in one place and not another as it leaks unless you have a massive restriction anyways. I'm missing something obvious here (I don't know much about the practical side/application on the car, but I've had some physics (just enough to be dangerous though)).

 

[Mellon]

the difference is that the wastegate stays shut until 14psi is reached so there's no leak until then.

on the other hand if you have a leaking hose while your turbo is trying to get up to 14psi before the wastegate comes into play it's going to take longer to do it and more turbo rpm to compensate for that lost boost and therefore more heat and possibly knock. The worse the leaks the worse the outcome.

is that any clearer?

 

[1LE]

Well, yes/no. Boost builds pretty quick anyways, so unless you completely blew a hose off I don't see that it'd have much impact. And then, you'd just never have any pressure, the turbo would basically be freewheeling at high rpm?

I'm just kinda curious as I had an episode a couple years ago where my BISS departed the car at high velocity while I was about 1/2 way down the local 1320. I normally run either 14psi (EVC on) or 8.5psi (EVC off). With the BISS missing (give a nice hole in the TB), I was getting right about 11.5psi. I took a couple passes with it missing (why not, I was already there) The times I ran were right what I would have expected for that boost level if I had dialed it in with the EVC. If the air was hot/I lost timing/etc, it wasn't enough to actually have an effect on my times/EGT. That's basically how this got started. I started to wonder why it matters where the air is leaking out. Just never ran into a thread where anyone was talking about it before...

 

[hostile]

Well, yes/no. Boost builds pretty quick anyways, so unless you completely blew a hose off I don't see that it'd have much impact. And then, you'd just never have any pressure, the turbo would basically be freewheeling at high rpm?

I'm just kinda curious as I had an episode a couple years ago where my BISS departed the car at high velocity while I was about 1/2 way down the local 1320. I normally run either 14psi (EVC on) or 8.5psi (EVC off). With the BISS missing (give a nice hole in the TB), I was getting right about 11.5psi. I took a couple passes with it missing (why not, I was already there) The times I ran were right what I would have expected for that boost level if I had dialed it in with the EVC. If the air was hot/I lost timing/etc, it wasn't enough to actually have an effect on my times/EGT. That's basically how this got started. I started to wonder why it matters where the air is leaking out. Just never ran into a thread where anyone was talking about it before...

Venting exhuast is different from venting boost. They are not the same thing, that is why wastegates arent on the intercooler pipes.

Either way if you were only running low boost anyways it shouldnt matter.

Once the boost is up in the mid 20's you might max out some of the smaller turbos sooner.

 

[Bohrn]

try this analogy.

You have a large bucket and a small mixing bowl. Your task is to fill the bucket with the mixing bowl. The trough that has all the water in it is 3 or 4 feet away from the bucket. Now, with the bucket good, you are able to fill it without breaking a sweat, just steady work. You are efficient and able to keep going all day.

now drill a hole in the bowl. Now you will have to move quicker to keep more water going in than is going out. Takes 3 or 4 more trips to the trough to fill it up.

Now drill 3 or 4 more holes. You can still do it, but you have to work your ass off and can't keep up after a while. Your system is now inefficient and you are all hot and grumpy.

Some people will combat this with getting a bigger bowl,(20g) or even a pail(gt-14), and this will work, but there is still gonna be leakage, and even that big turbo will have to work harder than it needs to.

 

[Mellon]

right and I'm speaking from first hand experience.. I noticed that I was having to set my boost higher and higher to reach my target boost and while doing that the knock was getting worse so I had to pull more and more timing until it finally dawned on me.. I have a problem here.

I did a intake pressure test and it leaked out pretty quick.. I could hear air escaping around the plenum area but couldn't find it. With a stethascope (good lord the spelling on that one??) to my horror it sounded like it was in the block area

I did a compression test and sure enough I had 150psi (155 is stock on TT stealths) on all cylinders except for #4, it had 30psi broken rings on that one.

honed the cylinders, new oem pistons and rings and now I don't have to set the boost nearly as high on my ebc to hit my target and I'm able to run quite a few more degrees of timing without knock again.

 

[Mellon]

bump for update.. what's the latest?

 

[sweet97]

If the motor has no knock is there a max limit to the timing that is beneficial? I somehow had gotten the impression that high timing at WOT and high rpm's was not good.. Mark

 

[Mellon]

yes, adding a bit of timing will improve performance but taking it too far will hurt performance.. where that line is on a dsm I don't know.

 

[sweet97]

Can some of the guys list there max tining at WOTand upper RPM's? I cold raise the boost but I am at 20 psi now on 92 octane with the 50trm. Mark

 

[AL92]

I ran my 50 trim and got a 14.3 at 100mph with a 2.24 60ft.This was run on my tazzo vpc but its very accurate have run it at the track.It was 2.5 mph higher than actual track mph though.Still thats pretty slow I thought for a 50 trim but was at around 10psi.I have big problem as stock clutch slips bad past 10psi and can't run higher than 12psi or so on stock intercooler.
So it might be tuning partly but it also might be your clutch.A slipping clutch will kill mph and et.And make good 60fts impossible.
Also I might have bad compression now as am all of a sudden blowing lots of smoke at idle.Have to check that out also.

 

[td06hkiko]

Can some of the guys list there max tining at WOTand upper RPM's? I cold raise the boost but I am at 20 psi now on 92 octane with the 50trm. Mark

18 deg's timing is good. anything higher is better for race gas.

 

[awdsm drft]

Problem is the afc. Sell it. I've had enough of tuning that car.