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View Full Version : Disappointing results after upgrades-HELP!


spyrs69
05-30-2005, 11:32 PM
Here is what I started with:
87 GN, 57K miles all stock even filter.
New upgrades include:
new vacuum hoses
Duttweiler neck
K&N cold air
ported throttle body
50 lb. injectors with chip (93 octane/17 psi/for 50 lb. injectors) unk brand
Billet adjustable regulator
new pcv and Fram fuel filter
Walboro 340
hot wire kit
TE-44 turbo
ATR dual 2.5" S.S. exhaust-no converter
160 degree t-stat
ATR 3" mandrel bent down pipe with new wastegate control (garret type)
New plugs and wires
Screens pulled from MAS


The car starts right up and idles well with 17" of vacuum overall runs well. From a start and to W.O.T. the car is a bit flat with not much torque/power. When the turbo spools up, it starts to go well as the boost increases (set at 17-18 psi). When it shifts into 2nd and 3rd gear, it goes pretty well but it just doesn't hit hard like I thought it would. The 275/40R17 Nittos don't break loose at all. After all this work, I am disappointed in the car's performance. Is there something I am missing?
I installed an autometer fuel gauge onto the fuel rail using the autometer 4' braided and I do not get a fuel pressure reading. I have tried (2) different gauges and still no fuel PSI reading.
Also, should I adjust the boost with a needle and seat or should I only use the adjustable rod, having the computer to control the boost rates?

Any help would be greatly appreciated.

Keller
05-31-2005, 12:42 AM
Put the screens back in the MAF. Being out will only hurt the idle and not help WOT flow measurably.

Do you have any sort of scan tool? Knock buzzer? Anything?

Sounds like you've bought a LOT of parts, and I haven't heard one tool for diagnosis being used.

Use the rod for adjusting boost. Let the computer control things, as it can back it off when knock is detected. You do have the stock wastegate solenoid connected, right?

Your fuel pressure gauge may require removal of the valve in the end of the fuel rail in order to work. This requires a valve stem removal tool. Removing it will cause fuel to come out under pressure. Be careful and have a rag handy. Best to disconnect the fuel pump and run the car briefly (it will only run for a second) to relieve some pressure first.

My guess is that the car is tuned very rich. You have more than enough injector for that turbo. You need to be able to adjust the fuel, and not crank up boost. Can't get over ~15 PSI on pump gas safely. More with alcohol/propane injection or race fuel.

spyrs69
05-31-2005, 02:54 AM
Do you have any sort of scan tool? Knock buzzer? Anything?
I intend to get a knock sensor very soon. Can a shop test the air/fuel ratio?

Sounds like you've bought a LOT of parts, and I haven't heard one tool for diagnosis being used.

Use the rod for adjusting boost. Let the computer control things, as it can back it off when knock is detected. You do have the stock wastegate solenoid connected, right?
I do have the stock wastegate solenoid currently bypassed with a T and a needle valve to control. I will go back to the factory wastegate solenoid so the computer can control boost.

Keller
05-31-2005, 03:08 AM
A shop with a OTC, SnapOn, or similar scan tool could test the car. However, with what you will pay them to drive YOUR car around at speed, (wide open is where it matters, right?) and they may not be willing to do it (you may not be willing to have them do it either), you could probably buy the necessary software or device.

TurboLink software, DirectScan software, an OTC scanner, or a ScanMaster should be the first "go fast" goodie for these cars. Can't tell the players without a program, as they say. The ability to diagnose and tune the car will make every other part more effective.

spyrs69
05-31-2005, 04:19 AM
What PSI do you think I should run the fuel pressure at?
I am also going to run more boost via and IC sprayer and possibly water or alcohol injection in the near future. Thanks

kenmosher
05-31-2005, 09:42 AM
Good starting place for fuel pressure is 43 psi (with the vacuum line off).

If you are going to use alky injection, then a good scan tool is even more important ... without it, you are poking at it with a stick in the dark. Another good tuning tool is a wideband O2 kit ... something like the Innovative WB, FJO or PLX Devices kits.

spyrs69
06-15-2005, 12:40 AM
I did some testing on the nearly new wastegate, which I received from a friend. The wastegate does not begin to open until around 21 lbs. of pressure. I believe I have a high pressure wastegate actuator which is non-functional at my intended boost level of 16-17 lbs.
Now I can spend $100 on the standard boost level actuator or I can run some toluene or go with the alcohol injection system.
:confused: [B]Will the wastegate valve being closed via the rod (with the wastegate retarding boost) lead to lower rpm=higher boost levels vs. having the rod adjusted valve being opened slightly more and depending less on the wastegate to regulate boost? (both situations with a final boost level at WOT being equal)

kenmosher
06-15-2005, 09:49 AM
Wastegate closed = higher boost, faster spool

The ideal wastegate stays closed until the setpoint for maximum boost is reached and then it opens.

In reality, they tend to open before max boost.

spyrs69
06-16-2005, 02:57 AM
Thanks a lot for the help. I will advise......