Somehtings I am Noticing after the Turbo?

[Keith@FP]

How do I set the TPS? and where is it?
Or is it one of those things that either works or is fualty?

The TPS is strapped on to the side of the throttle body. It has a limited range of adjustment, but I don't think you're going to be able to adjust it yourself. Weren't you having trouble with your throttle body previously?

Keith

 

[1sty]

I have to keep my idle screw at about the 1500 RPM range otherwise the idle droops to 0 rpm when coming to a stop. I had mistakenly adjusted some allen head screw with a 8mm lock nut on the throatle body thinking it was for idle. I readjusted that back to the level advised by Bill which was all the way shut, then a slight turn. This I know was his best guess which of coarse is worlde better then mine. It basicly adjusted the butterfly opeing at rest.

 

[1sty]

I still think the Idle drops becuase of the combination of the added restriction of the turbo and my mammoth Alternator.

 

[Keith@FP]

My guess would be alternator. A turbo will not cause idle droop - or if it does, it can be fixed with the bypass screw. No need to go to 1500.

It could be that your butterfly still isn't in quite the right place. If the engine doesn't think the butterfly is closed, it won't know it's at idle. This will change the way it behaves at startup and when you lift off the throttle.

Keith

 

[1sty]

I'll reset that again to totaly closed. The alternator has been in for over a year now and no idle problems came about until the turbo went on. The only other thought is there is possibly a small hole in the intercooler. I did't notice aything in my 2 inspections of it before install but Corky mentioned it was possible. I know the I/C pipes are fine since I can pull on them as hard as I can and not disconnect them.

As always ,thank you for all the help Keith.

 

[Keith@FP]

If you had a leaking I/C pipe, you'd be short on boost as well. They don't tend to leak just a little...

Keith

 

[1sty]

That was originaly my problem but since the waste gate came set to 8 PSI I didn't notice the porblem since i was boosting to 6 PSI. 3 days later i only got 2 PSI so I knew there was an issue. Once fixed the car jammed to 8 PSI in a heart beat. Plus I figures an I/S pipe would make itslef worse over time like before where as a small unwelded spot in the IC would not become different over time, at least not quickly.

 

[Keith@FP]

I'd agree with that.

Keith

 

[1sty]

What is the expected gain of ditching both cats on these cars. Doesn't seem worth it unless its like 20 hp and faster spool up.

 

[Keith@FP]

That might be a reasonable guess, actually.

Keith

 

[1sty]

WOW, I didn't think it would be that significant.
Damn now I might have to do it.

Is velocity in a turbo charged car as important as in an NA car to keep power? I know when NA you want to keep the exhuast diameter smaller to keep up the overall velocity of the gas. When turbo I assume this would still be useful for lower RPM performance even though it might sacrifice high end power.

 

[Keith@FP]

Actually, the "backpressure gives torque" thing isn't true on all engines. Normally aspirated Miatas love big exhausts - we've got the dyno tests to prove it.

On a turbo, you want as little backpressure as possible. You won't lose torque from low backpressure.

Keith

 

[LinuxRacr]

Also check your down pipe, and Manifold for leaks. One thing to check is to see if everything is tight at the BOV. I now can nail the gas, and let off, and my engine won't even get close to quitting on me.