No Boost at Launch?

[Outpost]

The past few times we've taken our 87 T (see sig) to the track we've been unable to build any boost at the launch. The car pulls well from about the middle of first gear, but leaves the line very lazily. On Saturday at Bristol, the car ran a 13.20 @ 109 with a 2.2 60'. At the GS Nats earlier this year, we were able to 60' around 1.80 even with the tires spinning.
FP is around 44 psi, and all the scanmaster numbers look good. Any ideas?

 

[scottyb]

In the order I'd check first:
Lazy/stuck wastegate puck - or actuator.
Exhaust leak
Rich (doubt that one)
Leaky intercooler/piping.
No change to converter, right?

 

[strikeeagle]

Converter...

 

[JayLashua]

I don't think a TE 44 will spool good with the stock converter, that's probably yer problem, takes a while to get it going right? but if you kept power braking it for a good 15 seconds it'd finally spool up and then it'd roast the tires, right? upgrade the converter!

 

[Ormand]

Converter?

Did I misread the signature? Thought there was a nine-inch converter. Nine inches should be more than enough! I would think that the puck in the THDP would be a likely place to start.

 

[strikeeagle]

Converter...

 

[Outpost]

The converter is a 9" lock-up unit. It is the same converter that worked perfectly at the Nats.

 

[BLACK6PACK]

Red Armstrong chip?

 

[forzfed]

Originally posted by JayLashua
I don't think a TE 44 will spool good with the stock converter, that's probably yer problem, takes a while to get it going right? but if you kept power braking it for a good 15 seconds it'd finally spool up and then it'd roast the tires, right? upgrade the converter!

I must disagree strongly with you on that comment. With my D5, I pulled a 1.62 sixty foot and was on my way to 1.5x when my axle snapped. According to Direct Scan, the difference in spool was 200rpm compared to the stock turbo.

 

[strikeeagle]

Ummmmmm, it grenaded???

 

[Outpost]

The car uses Joe Lubrant chips, 009 injectors, and (for the last six months) the TE44 turbo from our '86. This combination worked perfectly on our '86, and all the scanmaster data is within the acceptable ranges.
If something in the tune-up was off badly enough to prevent the car from building boost at the line, shouldn't the scanmaster show something? Can a converter fail and lose its ability to stall at its original engine speed?

 

[JayLashua]

lol I swear i didnt see custom converter in there the first time!! ;P

nevermind my ignorance then ;o

 

[JayLashua]

Also, hmm, do you have any exhaust leaks? that could affect spool up , cracked headers/whatnot

 

[strikeeagle]

Ask Bruce (aka WE4) in the Transmission Talk area for symptoms of a converter failure...

Alls I know is, my GN with a TE52 and a stock D5 did 12.0's at 118+, with 2+ 60's, so I'm of the opinion that a bad or, in my case, mismatched converter is the root of all evil...

Good luck.

 

[GrndNatnl]

I have that same problem. Only mine is because my brakes arent strong enough, and my trans is pretty fresh. Being so tight, it tends to torque through the brakes and either spin, or drag my front tires across the line. Next trick: S-10 brake cyls, maybe soft compound shoes, and a decent line lock.

 

[UNGN]

This is where a scan tool like turbolink or direct scan is worth their money.

What RPM will the car stall too? If the converter doesn't reach ATLEAST 2200 RPM, its the converter.

If the Converter reachs 2400 RPM and the turbo doesn't spool, its an exhaust leak, misaligned puck or you are too rich.

What is your max boost set at?

 

[Outpost]

The car reached 17 lbs of boost. Boost builds fairly quickly once the car is under way. I will attempt to verify the stall speed using the scanmaster (we haven't added a tach to the car).

 

[UNGN]

When running low boost, a car can be very rich on the bottom and not want to spool (and the wastegate may be opening slightly). If you got the octane and the converter checks out, turn up the boost to 20 psi and try that.

 

[87gnturbosix]

I'm using a D5 with a PT-51 and when I have the boost turned down to 17psi i can only build about one pound of boost on the line. With the boost turned up to around 20 psi I can easily build boost on the line.

 

[Outpost]

Thanks for the input, guys. We'll shorten the wastegate rod a bit at a time and test and see if the situation improves. The car used to be a tire-fryer and my wife is anxious to get that back.

This website is the best.