Max hot air boost?

[V SICKS]

With a fresh rebuild on my 84 engine and a tight stock exhaust system what is the max boost I can expect to see from this? I have no idea because I had to take it apart for rebuild before I drove it.. Was VERY sick when I bought it..also... do all turbo cams from say 79 up to 87 have the front grove in the journal? Considering the hardened cam brngs cause had bad grove in the stock ones on teardown.. THANKS. mike

 

[Jerryl]

In essence, you can go anywhere from 10-20 PSI, but not necesarily "KR free". There are way too many open ended questions to give you a good "KR free - boost number". Expect stock set-up boost level around 11-12, 93 octane.

If you list your combo and more specifically, your goal(s), there will be plenty of feedback and shared experiences.

 

[V SICKS]

Let me re-state this.. what is the max boost the turbo on this hot air car capable of putting out? Have 87 computer, will use 205 cam,balanced,bored 040,larger injectors, turbo has tag says rebuilt and is tight,looking at 2800 stall, have posi, port matched, new valves and springs, steel shim head gaskets, crank turned .010, rods resized, exhaust cracks welded and braced, THANKS ... mike

 

[forcefed3.8's]

If the turbo is stock, stick with the stock converter. I switched to a 2800 stall and lost some MPH in the 1/4. If you lock the converter, it won't be an issue, but I have never felt comfortable locking it. On pump gas (93 or 94 octane, maybe 92), you should be able to run 14psi to 15psi. On cold days, maybe 1 or 2 more. Just keep an eye on detonation and O2 mv. If you keep it from detonating, it will live a very long time. On 110 octane, you can run around 20 or 21. If you dragrace it, you can play around with the boost, but you probably won't see much of a gain passed 20psi. The turbo will make over 30, but it won't be making power. Get a good exhaust system. I ran the stock pipes with a gutted cat and 2 90° elbows in place on the muffler, and it was very quiet. These cars need to breath.

 

[Dwayne]

i've seen 35-37 lbs on a stock HA turbo.....by mistake........I would NOT reccomend doing this.......It pulled like hell in 1st and went downhill after that.....so to answer your question; the stock turbo would probably make 40 + lbs if you dare try.

 

[Bryan C.]

Anything over 20 psi on the stock turbo is inefficient and just produces more heat.

 

[coldair85GN]

The most I ever got from my stock turbo that actually helped get the car going faster was 20-22 psi..on 110 octane racing gas. The stock turbo is maxed out at about 22 or so psi if everything else is great because around 22 or so PSI the heat produced from it begins to slow it down so I always kept the boost around 18 or so. If you use alcohol injection you MIGHT be able to get gains up around 25 psi but thats pushing it.

 

[1984grandnat]

I hit 26 psi once with 93 octane and alcohol injection with the stock turbo, but honestly didn't feel any different than 18-20 psi. The alky suppressed the KR nicely, but the others are right about the performance above about 20 psi (not worth it to try with the stock turbo)...however, an aftermarket turbo may allow increased performance up to the 30-35 psi range, assuming that you can control the knock (even race fuel alone generally will not allow that kind of boost in my experience...plan on some experimentation with alcohol).

 

[MoeJr]

I think with the stock turbo you would be nice around 18 psi with alky and 93 octane