Lost boost?

hey guys, looking for some thoughts. I changed my supercharger belt today with another trd one, the old one was worrying me at 70k miles of use.... anyways, i also changed out the plugs for new ones. After test driving the truck i noticed i was only getting about 6.5 psi of boost with the urd supergrip pully. I can usually hit 7.5-8.0 so this is bothersome. I checked for a gasket leak but was unable to detect one with soapy water. I also thought that in order to be leaking 1psi+ at that volumetric flow rate, it would need to be far more than a bad gasket. My only thought is that the new belt may be slipping a tiny bit?

Any thoughts are worth considering.

 

Did you pull the charger yo install the plugs, or no?

Try vacuum capping your bypass valve. Do a test drive, and see if you boost goes back to normal.

If not, it might be the belt of the tensioner.

 

I did pull the charger off. There was slight damage to the manifold gasket which I tried to repair, but I'm going to pick up a new one tonight and put it in and see if that helps (which I doubt, but it will make me feel good inside.). I will also try the bypass valve trick tonight if I can. I was playing with it when I took the SC off.....cause that's what us kids do. Is it possible I damaged it? It didn't seem to move/spring very smoothly when I was messing with it.

So yeah something is wrong because I was getting 8psi the day before and now less.

 

Which seal? The cap, or charger to lower plenum?

Correct in the assumption that the bypass valve should move freely. Not saying that it is the part at fault, but it does go out. Helped a few members with that same method above, prove that their valve was bleeding off when it should have been completely closed. @memario1214 comes to mind first.

 

The gasket I just replaced is the plenum gasket. Hope that does something. I tried blocking off the bypass valve and it still only rose to 6.5 psi. And felt weak while I was doing it so that was odd.

 

So it doe cycle, but I can hear and kinda feel the spring creaking and groaning as it cycles. I will try it here shortly after dinner and see if I made it better or worse.

 

Yeah thats what mine sounds like. Also i did that with the hoses, and they are in the correct place.

I just did a test run and still 6.5 psi. As far as noise goes it doesnt seem like its winding up as much as it usually does either, like its not getting that full rpm im used to.

Wonder if its the tensioner allowing the belt to slip? I dont know of any good way of checking this. Its not making any noise.

I find this all odd that it happens right after i do a belt and plug change.

 

Was the belt the same brand as before?

 

I do not recall, I called up toyota and had them order me a replacement. The old belt was the same one they themselves put on 70k earlier. I will have to check tomorrow to see what either one said. I think the new one says ac delco?

Im debating on what to do next. order a new belt? Buy a new tensioner? I don't even know where to find a tensioner. May have to go through magnasun.

 

Here is the part number:
PTR29-35074. Easy to find a replacement if needed.

 

Excellent, thanks for the part number, i was looking everywhere for it and kept getting the tensioners for the 1st gen tacoma.

Because of cost order, im going to start by ordering a new belt. A gates micro-v. Maybe that will make some difference for a lot less money.

I just want my truck to feel like it used to, its killing me inside.

 

Turn up the boost while you're at it.

 

I gotta get back to the 8psi I had first before I go searching for more. Also I'm at the point in my life where I cant really justify any more performance adders on the truck (building a house). If URD had finally come out with the UCON for the later years I would have done it, but now its too late.

Also,.....so i'm going to try a belt conditioner first.....see if that has any effect. When I pick that up, I will have them order the gates belt. Hoping this fixes it. I don't want to spend the $230 on the tensioner.....especially if that also doesn't fix it lol.

 

So, I tried some belt conditioner. Did not help. In fact now it seems less at 6psi.

New belt? (Other than the new belt that is on there)

 

Just an update, I put the old belt with 70k on it back on and im up to 6.8 psi. So im thinkng its a combination belt and tensioner. Ill be ordering both soon.

Also.....anyone else see the claims on urds facebook about the ucon for 09+? Aparently next week its out.

 

That will be good. Good for a lot of people.

 

Sounds like you've narrowed it down.

 

I think I have. This is the most interaction ive had directly with the charger since i bought it, so i have learned a lot. And now I've realized how simple a setup these things actually are. There are litereally only like 5 reasons/places to loose boost. Most are easy to checkd cheap.....except the tensioner.

If i get it back to snuff after the tensioner and belt change ill be sure to post back here to help others in the future.

Also, loving the other thread about the radiator and spal fans @Torspd , I want them for the (what appears to be) extra space and the gained back power from the crank.