Built motor with all those high dollar parts years of planning and no EBC? No need for that heavy spring in the 1st place if you are using EBC. Something in a 7-9lb spring should be plenty with EBC and the power levels you are shooting for.

By the way. With my lack of any real knowledge that was my ass talking just now.

My only add in on that is... use the highest spring you are willing to have as your "low" boost. It just makes everything a little easier in the system. Allows you to use a MBC for higher boost later if you are unhappy with EBC results too.

I'm running a 10.x spring on my stock 1.6l.

Personal opinion though.

Split - Thanks for the save. I didn't think it made sense for him to be using a 12-14lb spring when he isn't running that high. You said it much better. Spring should be equal to your low boost settings. Well said.

unless you have some butterz flow going on.

My 6psi spring (with a ported wastegate outlet) creeps me up to 12psi currently.

http://www.boostedmiata.com/dynos/wastegate_spool.jpg

the ebc is not hooked up yet because the motor has a whopping 140 miles on it. I want a 3psi spring so I can go ultra-low boost with baby throttle inputs. Think "4th gear, closing radius, off-camber, over a crest" or turn 4 at hallett. I didn't request a spring that heavy. I ran a 3psi spring with a profec b on my last turbo car and it was flawless.

If your car turns out anything like mine you are going to be shocked at how driveable it is with all that power. I was afraid it would be too on/off or would have that turbo lag kick like my Saab had. It really is very linear and easy to control.

There is some controversy regarding engine break in out there. There is the baby it for 1k vs. the hammer it right off the bat crowd. Both sides can point to plenty of support data. I'm leaning a little toward the hammer it crowd. I wouldn't put full boost into it but I wouldn't be afraid of 6-8psi, unless your engine builder/guru/sensei told you otherwise.

the car is seeing 7psi after 5k rpm...I'm just not ready to hang it in the red at 14psi in 4th gear yet. I wanted good ring seal, so it saw a very small amount of boost and lots of vacuum on break-in...then enough boost at 5psi to go through a tank of fuel in 120 miles. lol I want to put 1000 miles on it before the track or dyno.

He he he. Big injectors and boost sure don't help the mileage do they?
I'm not much different freeway cruising but around town it's pretty bad. At the track it's unreal. Only good for 3 - 20 minute sessions. Gotta gas up again for the later sessions!

Driving fast sucks gas. I get 6mpg on track. 16mpg around town. 28-30 on the highway at 70mph.

Once that motor has about 100 miles of solid break-in (high vacuum, a little boost, varying revs) it's good to go. You think race motors get 1000 miles of break-in?