smoke in 3rd....alot

[Steve Wood]

btw, why don't you show us how you made your leak detector for the intake...

[Shimy87]

soup can with valve stem I had laying in toolbox, can was 3 inch and intake coupler is 2.5 so kinda a bitch to get it inserted but worked fine.

[Steve Wood]

I don't remember if I saw someone use a section out of a bicycle tube or I had that idea...it can be a very useful tool at times...

The thing that kept bothering me is that a TE-44 turbo is capable of flowing about 850 cfm.  It takes a heckuva leak to keep it from building boost.  That kinda eliminates the average exhaust leak and it's really hard to have that kinda leak past the rings particularly if the rings are sealing well enuf to have good compression

[daveismissing]

Can we summarize at this point? leak on the intake gasket, bad coil and ? and ?

[Steve Wood]

And a bad check valve

[Shimy87]

Yup those 3. All appears in order now. Just have to hope the snow stays away til after the 18th so I can see what she runs!!

[Shimy87]

tuning question. now set at a bit under defaults for fueling ( 125 in 1/2 and 3/4) its rich at 820 with 24 LBS boost. For best time should I lean out 24 lb boost setting or increase boost to get O2's in the 780 range and then fine tune fueling with chip from there? I'm guessing with this fueling setting I could turn boost up to the 27lb range before I get to 780 O2's?

[Steve Wood]

I would turn the boost up to get it where I wanted it.  I would aim for 25-26 and if still rich, start knocking it down a couple of percent at a time for third gear around 100 mph or more if you have a stretch where you can do it without getting a ticket.  At the track, you want the fueling to give you about 750-760 at the finish line with no retard.

I know I have referred you to this from my site a few times, but I will paste it here in case you have never read it.





This is what I do, I set the fueling to 43 (TT chips) and I drive the car until it is fully warmed up and I have done some stop and go driving, then I stop and look at the O2s in gear idling.  If they are 780-800 and the car is idling well, I call it good and forget it.  Note that the O2s will change when you stop and the O2 sensor starts cooling down so your 780 might increase to 810 in a short period of time.  Don't be confused because this is a function of the stock o2 sensor not a change in fueling.

If, when I first stop, the o2s read something like 820, then I reduce the fuel pressure 1-2 psi and try it again, until my first readings upon stopping are in that 780-800 range.  Remember that the TT chips are open loop at idle so that first blm cell is not adjusting the fueling like the factory chip.  It does have some learning capability, however, so that is what I like to drive the car for a bit before beginning to play with the adjustments.

If everything is right, the O2s should be pretty stable wherever you set them and they should not be jumping around at idle due to the open loop feature.  That is why the idle is normally smoother and better.

When you come off idle, then the chip goes to closed loop and the o2s will jump around a lot more as the ecm takes charge.

In essence, you can use the fuel pressure to set up your idle and low speed blms but I only look at the idle O2s first when I stop and the sensor is good and hot.

Now, remember that the fuel pressure affects the entire fueling range so the wot fueling will be a little leaner than what Eric put into his default  if you reduced fuel pressure at idle with the HOSE OFF so you need to look at the wot fueling to see if it needs adjusting.  Normally, it will probably not be noticeable because the chip was probably a bit rich to begin with for safety's sake.   Be sure to put the hose back on the regulator before you drive it again!

Now, having done this, I go to the wide open throttle setting and start dialing it in.  This needs to be done at the top of third gear so it will approximate what you will see at the finish line.  At this point, I am leaving the timing alone (using the default in the chip) and have the boost set for whatever Eric said the chip was burned for.

If the chip was burned for 25 psi, I would not be surprised to find that the chip was giving plenty of fuel for that boost level and no timing retard was being shown on Powerlogger.  If I am leaving the boost at 25 which is generally a good level for the street when using alky, I start removing a bit of fuel-say no more than two numbers at a time and making a run after each adjustment until I see the slightest hint of timing retard.  I then add about 3% of fuel back to the wot throttle setting and call it good.  I prefer to hae some margin of error-particularly on a street car where ambient conditions can vary widely.  This is done with Position 1 in the chip.

Spraying Methanol at 100%, I would expect my oem O2s to be around 780 on the street.  When at the track, I might lower my fueling a bit and look for something around 750-760 mv but in all cases, I am not going to accept any timing retard on PowerLogger.

Once I am happy with third gear fueling at the top end, I would look at the O2s in first and second from a launch.  Again I want to remove fuel until I am on the verge of timing retard and then add 2-3% back for some margin of safety.  I would guess the O2s will be close to 750 mv but the main thing is NO TIMING RETARD.

If you push first and second too much, you will create a lot of heat in the combustion chamber and this may push third gear over the hill so be careful and don't cause detonation in third by going too far in first and second.  Tuning is a tedious business and there are no short cuts nor magic numbers..  It is all about what works on your car with its combination and the ambient conditions around it on a given day.  That is the reason I like to leave room for a margin of safety.  I like living to fight another day instead of fixing what broke because I was too aggressive.

[Shimy87]

Thanks Steve, yes I have read that many times    I mostly wondered about a good boost target, I'll set it at 25 and tune away!
 
you never know but I'm guessing the track day will have temps in the low 50's so car should run well, tires are the weak link but we have covered that issue