I dont drive my car, mainly becasue i have a issue that i havent cared to fix. My boost is supposed to be about 9-11 psi. Im seeing about 15-17+. I dont know where it maxs at bacause i let off. I am a turbo noob, but im getting really good at replacing head gaskets Its a little frustrating to see all you guys making good numbers and able to make full passes at the strip and mine has to be babied and cant even go WOT for fear of blowing it again.Im also thinking of ditching my carb soon and going with a Powerjection3 or FAST set up.Wheni first contacted Tial, they said to use a 60MM now its 44mm??? Any ideas?

My email to Tial
I have a 38MM wastegate/50MM BOV on my 65 Mustang with a 349 and 70MM turbo. I wanted to run about 9-11 psi. When it was dynoed, I was seeing about 11-12 psi, so it was tuned for that. I have been having issues where the boost is seeing about 15-17 psi, it has been this way for a couple of years. I have contacted several dealers and they all say a 38MM is fine for this application and that's what they sell on similar combos. Many of the racers also use this same size. What is causing my spike? My turbo kit builder has since stop using your product because 3 engine with the same part have the same issues from excessive boost. I have what looks to be a small blue blue spring which should be the 8.9 psi spring. Is this part defective or what is wrong with this combination.

their responce:
Hello,

A 38mm is far from fine on that application, you would need at least a V44 to control boost that low. I'm not sure where they are getting the idea that a gate designed for running very high boost levels/medium boost levels on smaller engines could control 9psi on a 350, it's just not possible. The only way I can see this working is if you were using a pair of very small turbos with twin 38mm gates.



Regards,

Jake

TiAL

 

if it was because the wastegate is too small, then you would see it kreep. I think that is to small in my opinion. Check everything first. If you put the vacume line on the wronge end it will just go up and never stop. also find out what spring you have inside of it so you now where it is suppost to open.

 

I was having the same issue with 2 different 38mm Wg's. I wanted boost around 12lbs. and it was going past 20lbs. I put a XO2 60mm on the car, and everything has been fine since!

 

The spring inside is a small blue, which according to their site is 8.9 psi. Its not creeping it shoots right to 15+. The car has been the same since it was put together so nothing has been changed or rerouted.

I dont have a problem replaceing it, i just want to make sure thats the problem.

 

its to small for that motor.

 

I run dual 38's on my 352 just because I want to run low boost sometimes and didn't want any problems.. I have 5psi springs and it will hold 5-6psi all the way to 8000rpm. On the kit I am using they didn't put the WG in the best spot. If it was placed properly than it should hold 9psi IMO.

Where is your WG placed? Can you post a picture? Did you remove the WG and inspect it to make sure the value is opening and opening all the way? When I installed my 2nd WG a TINY piece of weld went on the WG valve stem. It kept the WG from opening anymore than 1/4 of the travel. How is your vac line to the WG sourced? Is the vac line damaged at all?

 

Here's a shot the w/g placement.The vac line it from a fitting in the manifold under the carb going to the BOV also.Lines have no cracks or leaks as far as i can tell.

 

That WG placement is part if not all of your problem IMO. That 180* pipe leading to it is no good. I would install that WG on that pipe just as it comes out of the larger pipe, taking the 180* pipe out completely. That would give the WG a nice straight shot of exhaust.

Another thing you can try is taking the WG off completey and see if/how much boost you get. I would still move the WG though.

 

I agree the 180 is no good... and IMO you would be better off with a 60mm WG If you want to run low boost #s with that cubic inch and a 70mm turbo...

 

Thnaks guys.

Heres what i dont understand.People on here do use a 38MM without problems correct?Is mine just a placement issue or is there more to it?

 

I have a 5.0 w/ edelbrock performer heads and a holley systemax intake with a 66mm turbo and I use a tial 35mm and can hold a steady 5psi boost. My WG dumps to atmosphere so that prob helps a little. It looks like yours dumps to atmosphere too is that correct? Your placement is great but the 180* turn has to kill the flow. It would be interesting to remove it like said before and see if it makes any boost. It seems like it shouldn't but ya never know. If it makes a significant amount that would prob indicate that the 180* is your prob.

 

Yes, mine dumps to atmosphere also. Now im curios if this will fix my situation. Im not running a buch of boost, i just wanted about 9-11 psi and be able to floor this thing and see what heppens

 

Take the WG off completely and try it. Of course proceed with caution as to watch the boost and your A/F. Also make sure that the exhaust gas coming out of the pipe will not burn anything. That WG setup is no good. Lose the 180* pipe and I think you will be surprised.

 

your placement is a big no no . you want the exhaust to hit the gate strait as possible. i would suggest a 44mm with a properly placed gate would surfice. most with 38mm gates can get a little creep even on 302's. 44mm would be just fine with what your after, but you have to move it. hell i mounted mine(38mm) directly on the crossover pointing down and held rock steady with a 11:1 built 306. you need to move the gate(.) no if and or buts man. move the gate and see if it works. put in a 6psi spring and see what happens it will likely hold steady with it getting pressure pushing it open.

 

There no problem with its actual placement. It's at the end of a bend, where it heads straight into the WG tube without interference, doesn't have to make a turn to go into the gate, and it vents both sides. The wg placement is dictated by a severe lack of room, hence the 180. Now I've got several cars that are in the same place, at the end of a bend venting only one side. It was straight tubing on these, and it worked fine. Including a 349 that held a steady 9psi. I don't know why it changed, or what happened. But this car, mine and the 349 all jumped in boost. Mine went from 12 to 14 psi. The other 349 went from 9-15 psi. And this one here dynoed and ran on the street with about 11.5 psi. One day I get a text that it's going over that, and still haven't figured it out. I don't know if the ethanol went up here in the fuel or WTF happened. But around the same time they all went up in boost. And I don't mean they started to creep. You hit the gas and it goes straight there. Mine was 14 on the brake.

 

I was waiting for you to chime in

Im just looking for a fix, any fix so i can drive this thing like its supposed to be driven

After this i'll figure out the carb issue if its still lean and then decide on fuel injection

 

It won't go lean as soon as it doesn't over boost. Ever put that hobb switch on there so it would cut ign for over boost ? Just gonna have to get a bigger gate. Not sure if Rich will get by with the new bigger turbo or not.

 

well the car hasnt moved for the past month.The headgaskets have been holding even seeing the 16/17 psi for a split second, so now i'm moving onto the the boost issue.Never did the hobb switch, my foot is the switch.Sometimes it works and sometimes it doesnt

 

Have you tried a weaker wastegate spring?

 

If it's carbed or EFI it will lean out if it's only tuned for 12 and goes to 17. Can still call me about the 40mm if you want. I text you back about it and never heard back from ya. Or we put a big knock off on it.