How much relief to I need to be able to turn up the IP moderately without making a lot of smoke? I'm currently running 7x10 SAC injectors. Pretty peppy, but don't like the smoke. Have a set of stock injectors in hand.
Current setup:
Banks oiled air filter
60 mm compressor
stock turbine
PacBrake
3" Banks Exhaust

Timing is bumped 1/8". I plan to go back to 1.25mm and put in the M&H dynamic timing spacer and a 3200 governor spring.

I'm thinking I'd like an aero exhaust muffler. I'm not interested in excessive noise or smoke, but I pull a fairly heavy double from time to time.

 

according to tst they got over 350 hp safely thru 3-1/2" im running 4" and went thru fender skirt to outboard frame, to allow a 36 gallon auxillary tank. diamond eye is popular at a reasonable price, the muffler shops have mandrel pre-bends for custom applications and usually come out cheaper yet, I did mine for less than 200. with a 4" 3 chamber muffler, then added a 1k exh-brake to celebrate all the money I saved....

 

A 4" diamond eye setup and ditch the oiled air filter

A exhaust won't do hardly anything for black smoke though, you need more air. Going to a better air filter will help but ultimately you need a bigger turbo. Better intercooler, etc would help a bit but of you have black smoke after turbo spool up, you don't have enough air

 

As I recall, you have a built automatic transmission? That makes things a little different, but my first question is, where do you need more power/less smoke? At 75 on the highway, or accelerating from 25 mph? Or, in other words, are you really looking for more peak horsepower, or more torque rise?

 

Tranny has Goerend low stall converter in it, so grunt is important. I have torque to burn with the sac injectors, and also dark colored trailers.

Plan is to go back to stock and start over. Timing at stock, M&H T1 dynamic timing mod, and new stock injectors. Compressor is already upgraded to 60 mm. Spool up isn't that important, especially with an automatic, as you don't back off the throttle to shift. Likewise, the stock fuel pin, maybe rotated some, should be adequate.

Don't like the Banks (K & N) air filter. Is there a decent filter that fits the standard housing, maybe after going nuts on it with a hole saw? Or what's a good BHAF setup?

As I'm going at it, I think I'll sub a piece of straight pipe for the muffler. If it helps, I'll put in an Aero 3030XL muffler.

Want to trade a little torque for clean, as long as it doesn't get ridiculously wimpy.

 

bump

 

I run the stock filter with about 6-8 2" holes in the filter housing.

I have my pump tuned to reach ~1300EGT when pulling 9K up a hill (40psi boost, stock injectors, same timing setup as you will be running). I feel i have plenty of power so you should be fine.

 

You have an inter-cooler? If so, stock ?

 

yes, yes.

 

Does your turbo have a wastegate? My 89 didn't have one and the boost was pretty tame. I shopped around and found parts for a later model turbo with a wastegate then I got a boost regulator gadget to be able to turn it up to about 40# boost. No more smoke.

However you may find that smoke isn't that bad a thing. It takes fuel to make boost so a little smoke when you romp on it is normal. Once the turbo boost gets up to speed the smoke will leave. You can have to much boost also which robs power. A little extra boost helps keep the turbo temps under control.

It's tricky getting the right settings between boost and fuel but that's where the fun is...

Edwin

 

Maybe I'm just being slow, but I still don't completely understand your current problems.

Reducing restrictions in the air filter & exhaust will not do much to reduce smoke below 2200 rpm or so, although it can help reduce turbo lag. I keep thinking that you might be concerned with excessive smoke under mid speed (say 1500 -- 2100rpm) acceleration. If that is the situation timing, AFC adjustments, and of course your SAC injectors are the big contributors.

In my opinion, the "stock pot" style air filter to house a BHAF is the best solution. I have never found the right "pot" to start with, so I just run a BHAF under a plastic drip guard. This lowered my exhaust temps over the K&N, by over 100 degrees, but I am sure the intake air is warmer than it could be. And the filter minder barely registers before its time to replace the filter (unfortunately I installed it with the BHAF).

So far as exhaust goes, I put a 4" down-pipe back exhaust on 12 years ago -- it helped with temperatures, but I'm not sure it had any effect on smoke. I think it is fair to say that the 3200rpm governor spring will demand a freer flowing exhaust, but I expect that is going to come from exhaust temps, not as smoke control.

And, of course, there is always soot unless you have a dpf . . .

 

Of course, that's why step #1 will be to change out the SAC's, and adjusting the timing so I can start the fire in the bowl, which should limit the bad idle haze I've had with both stock and SAC injectors. Dynamic timing mod should keep it singing properly up to about 3 grand.

Good Info. I suspected my air filter was part of the problem.

More good info. With the PacBrake, changing the down pipe gets complicated, involving custom fitment and welding. 4" the rest of the way is not so bad to do.

Thanks for the input.

 

Play with the smoke screw and star wheel. You likely don't need the extra initial fuel with injectors that big.