Very slow to boost, to much lag

[72nismo]

So here I go with, yet, another problem and question. Just for reference, here is my setup:

KA-t370cc Inj.JWT TuneBaby Turbo w/ stock actuator(not sure size but its ancient--personally ive owned it 10+ yrs.)ITB's 92 camsOk, so here is the problem:

Currently my boost is set at 10 psi and I have an 11.2-11.5 AFR at wide open throttle. When I boost the car, it takes a long time to reach full boost. The boost gauge moves more like a tach. 1st gear I get up to about 2-4 lbs boost - 5500 rpm apprx, 2nd it slowly climbs to about 8 lbs and in 3 and up it slowly climbs to 10 lbs and max's out there. In the past, it always seemed like the boost would climb much faster. So my question is....do u think i need a new turbo, an actuator, etc.??? I dont even really know where to start in order to diagnose the problem.Last question is about the cams 92 / 95 will there be a difference in p/u?? What you think?

[72nismo]

Nobody has any suggestions??????

[eazye2000]

Are you using a blow-through setup? Maybe a gasket issue on the manifold/turbo/exhaust? I have no idea. Only suggestions I have. Maybe piping leak? Does it 'act' like it's running at 2psi at the 2psi? Does it pull harder at the 8psi? Maybe your boost gauge is effed' up or something? I dunno. Just throwing some stuff out there.

[DevilMB3017]

IIRC '92 cams will have a more aggressive valve lift.

As for the boost issue, maybe your wastegate acuator is opening too much? I'm sorry I don't know much about internally gated turbos...

[72nismo]

Not a blow through.

[2FourTee]

Check for leaks everywhere. If there are no leaks, have the turbo and wastegate inspected by a turbo rebuild shop.

[WDRacing]

Disconnect the wastegate actuator and take her for a quick spin. See if boost jumps up real quick, but be leary since your actuator is disconnected. If boost skyrocketes really fast then you have a wastegate issue.

Have you checked the turbo for leaks and play? If not do so.

WD

[72nismo]

Ok. Now if I remember one time the clip that holds the actuator in place came off as i was taking it for a spin and i had no boost though does that sound right? FYI I have a internal actuator.


Modified by 72nismo at 10:18 AM 9/8/2008

[WDRacing]

The turbo should have an actuator, a rod that goes to flapper chingus and the flapper chingus itself. If the rod comes off or gets disconnected the flapper will just stay open and no boost will build...or very little.

Got pics?

[72nismo]

Here is a picture of the turbo. Not a great pic. ]

[WDRacing]

Whats it off of, RB20?

Anyway, you should have NO lag with that thing and it's the exact wastegate setup as I described already.

WD

[neverlift]

sounds like a wastegate or pre turbo leak to me, my car would run fine but only make a little boost, and more in every gear I would go up, just as you described, I thought the old *** actuator was dying on me....

long story short.... all my exhaust was exiting pre turbo, out my external w/g block off...

check for pre turbine exhaust leaks or a charge pipe that not tight,maybe coupler is split(happens often imo, me ,my buddy hawk, others)

hope it gets solved man

[72nismo]

I got that turbo of an FJ20T back in the day.When we blew that engine I kept the turbo for my KA set up.At 1st turbo pulled fine. I will check for leaks.

[WDRacing]

Damn, you don't here people saying FJ20 to often. Were you stationed in Japan or something?

[neverlift]

Damn, you don't here people saying FJ20 to often. Were you stationed in Japan or something?

[DevilMB3017]

I got that turbo of an FJ20T back in the day.When we blew that engine I kept the turbo for my KA set up.At 1st turbo pulled fine. I will check for leaks.

I'm sorry to hear your blew an FJ20T. That's one of the most badass looking motors I've ever seen. Kudos for turboing a KA with that bad boy.

It sounds like a turbo specific problem to me, not boost leak/exhaust leak, considering the age now as well...

[72nismo]

No not stationed in Japan. Back in the day you could buy the engines at your local imported used engine shops. Im talking in the early 90's. That was a badass engine. I would say it is the father of the SR20.

[72nismo]

Yeah you are probably right that is what I keep saying too the age of the turbo.

[72nismo]

Neverlift to my surprise yesterday i finally figured it out I had "all my exhaust was exiting pre turbo, out my external w/g block off..." like you suspected. car seems to be running strong again. Thanks

[WDRacing]

Awsome, glad it was an easy fix

[neverlift]

Neverlift to my surprise yesterday i finally figured it out I had "all my exhaust was exiting pre turbo, out my external w/g block off..." like you suspected. car seems to be running strong again. Thanks

oh I knew already mayn, my car was syck fast on 5psi, then all the sudden I need to start adjusting my w/g arm.... wtf, pulled my first block off plate to see it in a C shape. Now I have a 1/4" steel plate on that *****, 45 trim spooled at 2k whhhhhiiiiiiiirrrrrrrr/phhhhsssst/whistle/POP/smoke cloud/ repeat

glad to help, once in a blue moon I am right/close.

may not be open d/p like myself, but I noticed the sound as a major change, bov sounded weak,couldnt hear my wastegate slap shut,no more spool noise , now it smokes from eating that coupler

[72nismo]

Thanks again guys..

Now i have to deal with wifes G35 problem..