Slow spool up

[shannonlujan]

New to the SVO and the T3 so bare with me.

I've been used to my fast spooling IHI in my Mazda MX-6 GT, floor it,blink, and then boom full boost before 2800 rpm. In my SVO it seems I can't even get full boost until almost redline in 2nd gear. Someone told me I should be getting all 15 psi by 3000ish with the T3. My buddy's TC gets full boost around 3000ish with the stock IHI. Is the T3 that much slower than these IHI's or is something wrong you think?

[jayG]

My T3/T4 spools up pretty quick so I dunno what it could be exactly but I'll throw out a response anyway. Are you still using the stock boost control valve or an adjustable one? Also check the inlet tube( the tube thats between the VAM & the turbo, its a/b 3" in diameter) for stiffness. If its not real stiff it could be collapsing under acceleration and may effect spool up?. But its probably not the problem if the car does not stumble at WOT but it maybe worth the effort to check. If it feels soft just put a piece of 3" exhuast pipe in it. It could also be a bad turbo gasket, maybe not getting a good seal on the manifold. Just some things to check. One thing I've learn a/b these cars is that its not always the obvious when trouble shooting. Good luck...jG

[SVOeric]

is your cat clogged ?

I

[shannonlujan]

Jay: I'll check that VAM hose. I just recently changed all the vac hoses to the stock BCS and wastegate cause of an overboost problem. I have also noticed a slight decrease in boost ( according to stock gauge, could be gauge too???) here lately. I guess I need to get a MBC and boost gauge next week to help me diagnose problems. About the turbo gasket, the car has allegedly only 85k on it with an alleged recent motor rebuild, plus I can't hear any exhaust leaks but, i'll check into it.

SVOeric: There has been some obvious exhaust work done, I'm not sure if the cat. con. has been replaced but this COULD be it.


Thanks guys, I'll check these things out.

[turbizzy]

clogged cat

Shannon, i think your cat or something in your exhaust is definately clogged and its only a matter of time before it completely blocks off your exhaust. I don't really think its your gauge either, innacurate as it is, its still ballpark withing a few psi i think. Same symptoms happened on my 85 and on my buddy's 85.

Try jacking up the passenger front side of the car and with a 5/8"(?) deep socket and 2 long extensions remove the downpipe flange nuts and disconnect your downpipe. Next secure it somehow so that it doesn't just scrape along the street but leave it off the turbo. Then go for a test drive, won't really be too anoying but a little loud. Im suuure you won't be disapointed. Report back.

[shannonlujan]

I'll look into that as well turbizzy. I hope those bolts haven't welded themselves together from the heat. I don't have access to air tools.

[Gyrhead]

Heat em up.. or else

If you have access to a torch (MAPP, Oxy/Acetylene, or propane/oxy), heat the studs and nuts up well with a small flame. Once they're glowing cherry (or close), they'll come off without air. Otherwise, I suspect you'll be stripping nuts or breaking studs. If you don't have access to a torch set-up, you can try that Mopar Heat Control Valve Solvent Just ask at any Mopar dealership.. It's in the blue and black spray cans. It's the best rust penetrant I've ever found. Let it soak in well and consider re-applying.

Paul

[shannonlujan]

I'll try to get a torch or the Heat Control Valve Solvent. I hate stripping and breaking bolts/nuts/studs. Thanks for the advice.

It's coming off this tuesday after class, I'll keep yall posted.

PS: It's more than likely not the manifold gasket because the manifold was replaced with an aftermarket header so obviously it can't be THAT old.

[SVOeric]

if they used a 'paper' gasket, it could certainly be the gasket ---

on these engines, you don't use a gasket on the head to ex-manafold, unless it is one of the copper gaskets, and that's not really recomended, unless you can't get it to seal any other way

[shannonlujan]

Would I not hear the exhaust gas leaving the manifold? This was a common problem on my previous turbo car and most people immediatley recognized the sound of exhaust prematurely evacuating!:p

[SVOeric]

depends on where and how it's leaking, but yea, there is a good chance you could hear it.

[shannonlujan]

Well I didnt have the patience or tools to pull off the downpipe so I unbolted the exhaust right after the Converter and am in the prcoess of..."unclogging" it lol. Its being a real PITA though cause I don't have a drill, just a rod to ram in it. I almost have all of it out the exhaust note and throttle response has increased dramatically just from removing some of the asbestos combs. When I'm done I hope I'll be getting normal spool up and boost levels.

[shannonlujan]

Ok, it took me all day to gut it. I had to keep banging and crushing that crap with a bar and then drive it some to blow it out and then rinse and repeat. I still didn't get ALL the way through it cause it started getting dark. The more I took out the louder the turbine got (insanely loud, much louder than my buddies tbird and my mx6) so I knew I was doing good.

After I bolted the rest of the exhaust up it sounded just like it did before but maybe a lil deeper and after several test runs I determined that the boost is still rising very slowly. I'm getting 12 psi (via stock gauge) at approx. 5200 RPM in 2nd gear. On, "unleaded" mode I'm getting a hair more than 6psi.

I checked the VAM hose and it seems very sturdy.

I don't hear any leaks near the header and the K&N drop is clean enough. Could the BCS be causing these problems? I doubt it would cause low boost even on unleaded mode cause its not even used...

I'm stumped. I'm gonna order some 3 inch pipes next week and hope for the best unless yall have any ideas.

PS: I didnt get the Mopar spray. PB Blaster worked great.

[svobrown]

Could be the waste gate is hung. can you tell if the arm is free to move or is in the right spot. I am looking at mine now and the arm is almost straight with the flang of the turbo.

Mine is adjustable and can be moved with some air pressure on the vac line to the acuratore.
Better stuck open than close.
Ask me how I know.

[shannonlujan]

I'm goin to try some other things first before I test the actuator. If I have room I'ma see if I can pump it up with an air compressor or something and see if it has full range of movement. I doubt this is the problem but it could be.

It will be a major inconvenience if it is.