Embarrassed at the track..Boost problem

[BLACK MAGIC RACING]

I just came back from the track, where i was COMPLETELY embarrassed by a best E.T of 15.05 @ 89mph. The reason is as follows: I had my chip in (thrasher 92) but couldnt get past 1/2 throttle before the boost would jump up to around 15 lbs, and the car would sputter and backfire violently, sending the kr soaring to around 10-15 deg. and it seemed that after going down about 5 turns on the adj. gate, nothing was changing. So, i switched back to the stock chip, where i was able to get the boost up to 10 1/2 lbs before it started happening again. going any higher would get the same results as my thrasher, hence the 15.05 runs. fuel pressure was the reccommended 45 lbs on the thrasher, and 42 lbs on the stock chip. Running 94 0ctane pump gas, with additive. What could possibly be wrong? bad waste gate solenoid? PLEASE HELP!! CIVICS WERE PASSING ME FOR GOD's SAKES!!!

 

[TRBON8R]

Canuck,

First of all, don't panic. I had a similar severe boost control problem not that long ago. What I might suspect first is a bad wastegate solenoid. Don't assume that the solenoid is good just because it is new or has low miles. I had one that crapped out after only 3,000 miles.

To see if it might be the solenoid, first unplug the wastegate solenoid and take the car for a drive. When you boost the car and give it full throttle there is a baseline setting in the hardware that should give you around 13 psi boost. You will notice that the "Check Engine" light will come on since the computer will notice that the boost solenoid is not functioning. If you can floor the car and your boost control remains rock solid at around 13 psi you have most likely found your problem. The solenoid is bad. Hope this helps.

 

[John Larkin]

Sounds more like fuel pressure didn't rise with boost. I hope you have a gauge that can be placed in view while driving to check this out.

 

[squeeze87]

Bad coilpack??

 

[UNGN]

It's probably not a bad wastegate solenoid, if the motor is "crapping out" at 10.5 psi.

It could be a bad fuel pressure regulator or the vacuum hose to the FP regulator is loose or screwed up in some way. A long shot is your FP gage is bad. Very small chance of this, but it has happened.

It could be electrical: bad coil pack, spark plug gap at .050", bad wires, bad MAF, etc.

Don't get too discouraged. The first time I took mine to the track the swaybar was broken and I reused the tank to body fuel line when I replaced the pump (it cracked and at high pressure it was spraying gas all over the place)

The wheel hopping "2.4 best" 60fts were bad and the gas drips mercifully ended my night of running mid to high 9's in the 1/8th (low 15s). The great thing was that in a few week, all the people that gloated about beating me on my first night with my T-type, wouldn't race me anymore. strange.

 

[TurboDave]

As ungn pointed out, it's definately NOT a boost problem, since the car started acting up way down at 10# of boost. You should easilly be able to run 15# of boost with no troubles.

Most likely suspects would be fuel delivery problems or coil pack/module problems.

 

[BLACK MAGIC RACING]

The problem WAS in fact the coil pack, one coil was reading 44.5k , one reading 10.5, and the last one gave a 20.7K ohm reading. Thanks again for all the help guys!! new time: 14:30 with a cracked driver side header (almost no boost at launch) @98.77MPH

 

[Rayk]

Glad you found your problem. With your basic recipe your times should dip well into the 13s at 101-103 MPH. Here are a couple of things that may help you achieve that:

Lock the converter in 2nd gear
raise the boost to 16-17 PSI in 3rd gear
Lower the pressure in your ET streets to 18-19 PSI
Launch the car with 5+ PSI boost if you can hold that much.

Good luck,

 

[TurboDave]

Originally posted by Rayk
Glad you found your problem. With your basic recipe your times should dip well into the 13s at 101-103 MPH. Here are a couple of things that may help you achieve that:

Lock the converter in 2nd gear
raise the boost to 16-17 PSI in 3rd gear
Lower the pressure in your ET streets to 18-19 PSI
Launch the car with 5+ PSI boost if you can hold that much.

Good luck,

Pretty good recomendations, but I'd like to "add" to them.

first one: I never recommend locking the converter in second not without a transmission modified to handle the incredible strain during the 2-3 shift with it locked.

Second one will require good gas of course.

Third one" that's a good starting place for ET Streets... you will eventually end up lower than that of course for max traction.

fourth one: well, yes, as much as you can hold

 

[Rayk]

Originally posted by TurboDave
Pretty good recomendations, but I'd like to "add" to them.

first one: I never recommend locking the converter in second not without a transmission modified to handle the incredible strain during the 2-3 shift with it locked.

Second one will require good gas of course.

Third one" that's a good starting place for ET Streets... you will eventually end up lower than that of course for max traction.

fourth one: well, yes, as much as you can hold

As long as we're refining or adding to recommendations, I'd like to refine them a bit further:

First one: With a basic recipe stocker I "always" recommend locking the converter in second gear at the drag strip. While it does put additional strain on the converter clutches & tranny my experience has shown that the unit will hold up. Keep in mind that my experience has been with basic recipe stockers running in the low 12s. I've had four of them. My current WE4 has a GM Mr Goodwrench rebuild in it with over 45,000 miles and over 100 runs and it's still going strong. It doesn't even have a shift kit! Now, as you add aditional horsepower, that's a different story. But his car is a stocker.

Second one: I'm not sure what is meant by "good gas" but his Thrasher 92 should allow him to run 16 to 17 PSI boost with any kind of 92-93 octane pump gas. Thrashers are pretty low timing chips and may allow even more boost than that in a well tuned T/R.

 

[UNGN]

I'm glad you found the problem.

Fixing the Cracked header should now be the #1 priority.

Always fix the things you KNOW are wrong first before you do any other things to increase performance. It provides baseline so you can see the efects the other mods have on your cars performance. Problems like a cracked header will effect the ability for other modification that you may do to work properly. If you tune for max performance with a cracked header, you may have to start from scratch again on your tuning once the header is repaired.