No Boost till 3K???

[Putter]

ball on maifold side and spring on wastegate correct.

I'm not sure that the wastegate is original to the van. It seems very hard to pull the wastegate arm away from the canister. Could it be too short, or the wastegate spring too strong to set the boost level low?

Checked timing, and it looks like the previous owner installed a new belt but didn't line the cam correctly. I got it all lined up and timed at 12^ , it seemed to vibrate more at idle and ran a little stronger. Still no boost till 2700 though! Looks like I might have to rebuild the exhaust.

[Putter]

when you say no boost tilll 2700 do you mean like none in top gear or not peak in top gear, cause the higher the gear you are in, the sooner you can build boost (its a function of load primarily)

By no boost, I mean from idle there is no significant boost building until 2700. At 3k there's about 5psi, from there boost builds respectively with rpm till cut out. I seem to have a problem with lag, and overspooling. I'll recheck timing when I wake up, any more ideas are greatly appreciated.

[ltrain]

So when or I mean at what rpm does a mitsu start boost at.

Quote:

Originally Posted by ltrain So when or I mean at what rpm does a mitsu start boost at.

2700rpm.

On another note, I disconnected the wastegate line, and now no boost till 2700 and 15+psi at 4k. Spools much quicker even at 1/2 throttle I get the 15psi before 4k. If the wastegate flapper is not fully closed(say the arm is a little too long) could this cause the slow build till the little mistu can outflow the wastegate being open?

Plugged the wastegate directly to the intake. Still no boost till 2700 holds 5psi for a second, then creeps steady to cut off.

Unhooked the wastegate arm from flapper, same results as last post.

[Putter]

A mitsu turbo on a 2.5 with opened up exhaust it should be inevitable to have severe boost creep whereas the turbin and wastegate cannot flow enough to drop turbin pressures to keep from overboosting. I myself have never played with a mitsu but i have seen other very small turbins produce the same results in similar setups. Make sure your wastegate is fully closing is about all i can say without actually being there to see the car and diag it. Are you sure you have a mitsu turbo and not a garret?

Yeah, it's a mitsu I pulled it myself at the local junk heap. My original turbo was seized, couldn't find a garret for the life of me. So it was either the mitsu or nothing.
I'm not as concerned with the creep as much as the severe lag. I'll restrict the exhaust to help with the creep. I rechecked the timing and it looks like the distibutor, might have been off one tooth as well. Just getting it back together now, only have to adjust belt tension, recheck, rotate engine two rotations by hand, recheck, start it up and set distributor timing. I hope this finally works. Can one tooth make that big of a difference?

[turbovanman]

You either have a plugged exhaust if the cat is still in there, can't tell if you left it in. Or another possibility, you might have a TBI torque converter which has a lower stall and won't let the engine build boost properly.

Do this, put it in drive, put on the e-brake, left foot on brake and floor your gas pedal. About what rpm does it make boost and whats the maximum rpm you can get. NOTE, don't do this for longer than say 20 secs or you will overheat your transmission oil badly then you will have other issues, lol!

If you have a turbo converter, it should hit around 3500 rpm. If its a tbi, around 2000 ish rpm. You should get boost after a couple seconds of WOT.

No cat. I've already done the check on the boost like you describe. I'm pretty sure it's a turbo converter, I can get about 7-10psi wot at ~3500. I think the exhaust is too free flowing for the Mitsu(causing the creep).

[turbovanman]

Your not complaining of creep, your complaining of no boost down low. From what you describe, sounds like your setup is normal as everything checks out. Lag is a part of our TD's, Mine has some but you learn to live with it by using the gear shift, lol!

From reading this THREAD I had hoped to be able to see boost response the way they talk about it.