After going to hell and back with my build, the car is finally finished.

The problem is I cant boost more than 20-21 psi. My set up includes:

83mm Sleeved B18
Thermal R&D 3" (No cat)
GT3076R
Walbro 255
1000cc Injectors
E85
Turbonetics Evolution WG
Revhard log manifold

My wastegate is pretty old and on the dyno it appeared to be opening early. It had a 7 pound spring so I found some spacers and installed them into the gate to make the spring stronger. It worked perfectly, my gate now runs at 12psi. But Im still only seeing 20-21psi.

Do you think this is a gate issue, log maniflod issue or something else limiting my boost? The set up is smooth and puts down 440whp, I was just hoping for a little more. I've heard of people making plenty of power on log manifolds. What to do?

Thanks in advance

 

Sounds like that temp fix for your Gate has limitations. I mean, a 7psi spring can really only do about 17.5-18psi anyway, typically. So, get another gate with a better spring, and no more temp fixes.

 

Need bigger spring

 

Thanks. So you've seen revhard logs make more than 20psi/440whp? On a 30R...

 

Personally ive never seen anything with that manifold but typically the wastegate spring is good for double the psi that it is. So your 7psi spring should be only good to around 14-16psi but it doesnt always work out like that. So in your case 20psi is where the spring is too weak to hold that gate closed and make any more boost

 

I'll see if I can borrow a gate from someone to diagnose. What size spring should I get to run up to 30psi? Turbonetics said they'll make a custom one for me...