problem with over boost, fluctuating...

[bluehair]

where do i start? first off new owner of this car 86 designer t-type. 50 lb. injectors, new stock turbo, walbro fuel pump and hot wire kit, new valvesprings.....it had a turbotweak chip in it when i bought it but previous owner said it was a race chip...well it was up around 22-23lbs of boost when i got it, i have sense got it down to around 18lbs and thats as far as my acuator rod will let me go..??? it would be nice to have it down around 15-16 because of 93 octane is all thats in it now. but this was back around a few months ago when it was around 50-60 degrees here in KY. well i ordered a new TT chip for street, 16-17 lbs of boost, 93 octane...put it in today and took it out around town for awhile and its creeping up around 20ish now...im like what the? on a street chip? 93 octane? uh nooo... so its about 23 degrees here now. does weather make that big of a difference in boost levels? when i kick down on it from a roll or so it will go up to about 18 and then creep up to around 20...and i let off of fear of headgaskets in my lap. so i have replace all my vacuum lines, etc.. and that helped when i first got the car a couple of months ago. is there anything else to check? or replace? is my actuator rod too short maybe? because im out of adjustment and its at or was at 18lbs...

i did however put my chip back in it that came with the car and it still did the 20lbs creeping back and forth on boost...so its not my new chip. is there something going on here im not aware of? why wont it go down to 15 or so...???

 

[scottyb]

Yes, I have to adjust my boost based on temperature. The cold weather does seem to make a pound or 2 more boost.

It's likely you have a heavy duty wastegate actuator. they have a minimum of ~18 lbs. If you want to go lower, get a stock style adjustable actuator.

 

[bluehair]

the one i have l found a picture of in an old kirban book, so it looked to be from there? dunno... im going to modify it then so i can turn it down some more to 15ish anyways...

 

[TurboMonte 2]

I think running a HD WG controller (stronger spring, slower to cut-back boost, etc.) will continue to give you some overboost problems--even if you "modify"...

These were meant to run/ control boost at higher levels (in the 20's) than standard 15-17# on 93 oct. Just get a std adj WG controller. Factory stock ones were not adjustable, but typically controlled @ 13# +/- ...

 

[bluehair]

is there an easy way to tell by looking at it if its a heavy duty one or not?

 

[TurboMonte 2]

Well, now, you're over my head--as I've never seen a HD one

 

[bluehair]

no one else have this issue? is there really a HD actuator? and why?

 

[scottyb]

HD actuators have stronger springs, and generally hold to 18 lbs vs the stock ~12 lbs. One of the older methods of adjusting boost was to thread the actuator rod, and pre-load the actuator. The stocker can get you to ~20 lbs before becoming unreliable, so those who ran/run more boost all the time would get an HD. If you street drive and need to keep it at 15-17 with pump gas, then you can't use an HD actuator.

 

[bluehair]

makes sense. thats what i was going to do is use a couple of nuts with a coupler nut and thread the rod farther that away i have more adjustment..you don't think i can get 15-16 lbs doing this with the HD spring? or just not very reliable..of course im one of the lucky ones that can run 18-19lbs of boost without knock on 93 octane so that helps, but now that its cold its up around 20 and im not to crazy about that...just have to keep my foot out of it i guess until race gas gets here.

 

[scottyb]

IF it's truly an HD actuator, then the lowest you can get is whatever the spring makes (18). If it's extended to the point where you don't have to pull it to slip it over the WG arm, then you will get a boost level ~= to the spring in the actuator (plus any additional provided by the solenoid system). Extending it further will just make the wastegate be open all the time and you get no boost or very little.

Have you already legthened the rod as far as it will go? Do you still have to pull on it to slide it onto the arm?

 

[bluehair]

its almost like the rod is too short as it is. if i had a measurement to take for reference and check it i would but i dunno what the length is supposed to be. yes i have to pull on it pretty hard to get it to slip over the stem.

 

[scottyb]

its almost like the rod is too short as it is. if i had a measurement to take for reference and check it i would but i dunno what the length is supposed to be. yes i have to pull on it pretty hard to get it to slip over the stem.

Then that's the problem. Take off the nut and zip down to Ace hardware and get a longer one. Basically you should have to pull it less than 1/8 of an inch to get it on the arm.