Boost/Wastegate Adjusting

[6=8]

Hi,

Thought I would ask the experts about adjusting the boost on a stock GN with Ramchargers 93 street chip, stock everything else.

I recently added a set of Postons Headers on my 87 GN, and man did that seal things up! I am running a stock turbo, and with my 6 year old leaky ATR headers, I had tightened up the Wastegate fairly tight to compensate for the missing pressure. After getting things sealed up, I have very nice throttle responce and almost immediate Boost with even light throttle launches. Its nice to hear the turbo again!

On the down side, it now boosts way too much at anything past 1/2 throttle (Pop/KNR). Seems 15-16 PSI is a little much for my stocker. Boy the red LED lights up quick!

So, I am in the process of opening the "Puck" by adjusting the wastegate rod. So far, I can almost go WOT, but my drive around town requires more throttle than before, and boost takes longer to come up. The puck is actually held open a little now, and looks like it needs to be opened even more before I can reach true WOT.

Am I now looking at a more advanced boost control, or does this sound like a plugged cat or malfunctioning wastegate? How can I test to see if I have the wastegate vac lines connected? How to I test the wastegate actuator itself?

Any thoughts would be extremely helpful. Its been a while since I've had this much fun with the car. It amazing what a new set of headers and a set of valve springs can do for a 150,000 car! I will be reviewing some post searchs/tech archives for this problem when I get home tonight, but wanted to get some feedback on my specific problem too.

Thanks for any tips you may have!

 

[BLACK MAGIC RACING]

UPGRADE YOUR FUEL SYSTEM!!! you may not be getting enough pressure with the stock pump and wiring. Racetronix sells a good pump and hotwire kit, and Jack ships his stuff lightning quick!! This is the first thing everybody upgrades on a TR.

I may be wrong here, but i think you should be able to run a bit more than 15-16 # of boost with good 93 or more octane gas. Try disconnecting the plug that goes into your wastegate solenoid, and go for a ride. If boost stays steady at around 13 lbs and the popping stops, your vac. lines and solenoid are probably good. I've run up to 22 lbs. on a relatively stock car, with race gas and chip.

Another possibility is a bad coil pack. Get yourself a good multimeter and check each coil individually. you should get 11-13k ohms resistance on all coils.

Also, If you've never changed the cat, it may be a good idea to do so now. 15 years is a little longer lifespan than a normal cat has. if the car is going to be raced, a test pipe in place of the cat works well. a test pipe w/ dump is even better. boost gains of 2 lbs. and a much faster spool up usually result, although this is not likely the cause of your problem.

HTH

 

[6=8]

True, True!

Thanks turbo_canuck! I have been planning on fuel system upgrades (Still untouched stock injectors!), but based on my O2 readings, I may actually be a little on the rich side. BUT, I am a happy man tonight! I found the problem, it was definitly related to Boost. Too Much at anything over 1/2 throttle.

So, here are all the parts I have recently upgraded/replaced (Not counting all the little things like fuel filters, pcv, and hoses, etc:

1. Timing Chain (Way past due... missing about 7 plastic teeth in a row. Very lucky!) $45
2. Cam Sensor $125 (It was out during the chain job... I now have a Known good backup!)
3. TypeII Ign module and 45,000v coils (Another Known good backup) $220
4. Postons replacement headers $485 (Replacing the ATR SS, all 3 tubes cracked, Passenger Side)
5. Valve Springs $68
6. Ramchargers 92 street chip. $75
7. MSD 8.5mm wires (Not installed yet) $80

And after all that cash, still I could not get very far over 1/2 throttle. Even when running 100 octane fuel (4.89/gal), either too much KNR, or a loud POP! Some of the parts I listed did need replacing, some didn't, but nothing solved my problems. That is, until tonight!

7. Wastegate Orifice $4.00

Thats right... the $4.00 part has cured my boost problems! These replacement "Y" fittings and vacuum lines I have been getting about every 2 years or so have all been WRONG! The restrictor orifice in these so called "Replacement Parts" are apparently too small for stock applications with a well sealed exhaust system.

It has been a long 3 year journy back to the performance level I knew existed in my daily driver... I can only blame myself, though. I have yet to install a boost gauge. Since the factory guage only really goes to 15 psi, I never knew how far over 15 this thing was going! Had I installed one, I might have arrived at this solution a little sooner. BUT, unless I was looking for other parts, I would have never known that this little jewel existed!

I wanted to get this posted in case there are a few others "Nursing" the throttle trying to go as fast as you can without getting knock readings... try the 4.00 part! It worked for me!

Thanks for reading! I AM SO HAPPY TONIGHT!
What a car! Hey, who wants to have a beer with me!

A toast! To the engineers and assemblers (And even the managers ) involved in building these bad ass cars! Heck, at this point, I even forgive the mix of SAE and Metric hardware!!!!