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JFairman JFairman is offline
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Join Date: Jul 2006
Location: S. Florida
Posts: 7,224
I'm not sure about this because I removed the air pump from my car right after i bought it when I did a valve adjustment. You have to remove the 2 vacuum operated diverter valves, a little air cleaner, and some hoses just to remove the upper valve covers anyway.

There are 2 vacuum solenoids mounted on a bracket side by side on an '86-'89 USA turbo and they are wired together in parallel from what I remember and I think they share their ground wires with the ignition coil ground wire.

One of these vacuum solenoids blocks vacuum from reaching the vacuum retard side of the vacuum pot on the distributor for the first couple minutes after a cold start so the ignition timing advances and idle speed raises about 300 rpms.
At the same time the other vacuum solenoid sends vacuum to the 2 air pump diverter valve so air is injected into the air injection nozzles in the exhaust ports to help burn whats left of the rich cold start mixture where it is still very hot.

When the K-jet ECU under the driver seat stops sending 12 volts to the 2 - 3 way vacuum solenoids after about 2 minutes the one on the right lets intake manifold vacuum go to the vacuum retard pot which retards ignition timing at idle to about 0 degrees or TDC which lowers the idle speed and increases exhaust temperature so the catalytic converter runs hotter and lowers emissions. At the same time the other vacuum solenoid also looses the 12 volts and it triggers the 2 air pump diverter valves to stop sending air to the exhaust ports and divert or send it into the catalytic converter instead where it will add oxygen to heat up the already hot catalytic converter so it burns up the hydrocarbons and unburned rich mixture while you are driving after the 2 minute warm up period... lowering emissions so they could sell these cars in the USA again.

I just do not see how that is going to give you 5 horsepower. I can only see this emissions system adding weight to the wrong end of the car and taking away a little horsepower while adding a little drag to the driver side camshaft to drive the air pump all the time and maybe adding alittle more wear to one side of the intermediate shaft bearing in the process.

My thoughts on the origonal question:
1. Stock 3.3 USA motor with cat, quiet muffler, and good flowing OEM later style exhaust sytem/heat exchangers is 282HP.
2. Take off the cat while leaving the stock muffler and you have about 300HP.
3. Put on a straight thru glass pack type muffler at least 2.75" ID, with 3"ID being better and you'll get about another 15HP.

So with nothing else changed from stock, my guess to the origonal question is about 315HP.
Old 01-13-2010, 12:00 PM
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