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Regarding Nine9six's question on the amount of boost you should be seeing:
I would say that unless your gas pedal is about 1/4 way down - you won't be making any boost from the SC system.
With the charge cooler module installed you will see around 6psi max. Without the charge cooler you will see around 14psi max. Assuming stock pulley installed.
Normal driving - i.e gas pedal less than a 1/4 way down - you'll be in vac.
You should be tapped into the barb at the back of the intake manifold to read boost.
The instructions are vague at showing where all the connecting cables go for the brake booster, return oil, etc. Maybe confirm these are correct.
The install for the SC is pretty simple - sort of hard to go wrong - and is designed well - I have a feeling it might not be a problem with an air leak.
Maybe check the DME / Split Second box and wiring?
Check if you have any damaged wires for the MAF / TPS / Spark plugs / Distributor
Check the condition of your spark plugs - do we have a worn valve guide causing fowled plugs?
There was a time my engine ran rough and idled rough. Turned out to be spark plugs and worn value guides. It meant engine rebuild time.
This was my experience - hope it can give you an idea or two - I'd say your mind is clay at this point.
Hi Windydog. You should not be seeing boost at idle after the SC. There is an air operated valve that opens to prevent the SC from building boost when not needed (wastegate/bypass). There should be a vacuum line going to an actuator which mechanically moves the valve. TPC changed to location of the bypass in later generation of the SC. You may want to verify the SC bypass is open with vacuum at the actuator port. When the throttle is open (pedal to the floor), the vacuum should go away and the actuator should shut the bypass, allowing SC to build up boost pressure. If you do not have the vacuum line connected, you might also be seeing boost at idle.
Hang in there...we'll figure this out! You are going to love it when you get it running!
When pulling off my pulley today for the new 2.1" to match the Clewett pulley kit I cracked the supercharger snout shaft
ANyone know where I can get a replacement? What M90 Gen 3 supercharger is this? I called TPC and Tom basically told me he can't help and to call or send it to Magnuson to get rebuilt.... <SIGH>
Zero phone answers from Magnuson or email replies.
I purchased a new vacuum gauge to perform the test.
I hooked up the vacuum gage to the port behind the intake mainifold, after the supercharger. At idle i get 2 in of hg, and i play with the bypass valve and can get as high as 5 in of hg.
When i apply gas, the vacuum gage goes up, meaning going form 2 to somewhere in the range of 20 in of hg at the same location. This doesn't make sense since i should be producing boost and should be going to 0 at full boost.
I have no mufflers and only a catalytic converter which i purchased 2nd hand.
Question:
Is it possible that i have worn valve guides leading to the low vacuum? I never checked the vacuum prior to installing the supercharger.
Is it possible that i still have a vacuum leak.
The part that gets me is that Vacuum should decrease at the high side, after the supercharger not increase. What the heck is going on.
From my testing experience, I also found it difficult to check boost in a static situation (ie on the drive just revving the engine), may be just an instantaneous blip as the throttle was applied initially. It was only when the engine was out on the road and under load that boost was created and maintained. Can you hook the gauge up on a long hose and trail it into the car for a road test (get the wife to passenger and hold it!). Another thing I found out when I did my first road test was that if the sc pulley was too large for the Clewett setup, the engine under load was (normally) demanding more air than the sc was able to shift, therefore no boost, hence the move to the smaller pulley - but I think you've got that covered.
With all the works you've done on leaks, I doubt that you still have any vacuum leaks, or need to worry about worn valve guides being the cause. Get it out on the road. I'll bet fuelling is the main issue - do the full injector mod and be done with it
not to side track you I just thought I would show you my could air intake system. I know you talked about making something. This is the K&N setup. It's a 964 but still the 3.6L
You should definitely be seeing more than 2" vacuum at idle. If you have confirmed that the bypass valve is definitely open at idle, then my guess would be that you still have a vacuum leak somewhere. Would try the leak testing again. I will jump in my car and see what I see for vacuum for comparison.
I purchased a new vacuum gauge to perform the test.
I hooked up the vacuum gage to the port behind the intake mainifold, after the supercharger. At idle i get 2 in of hg, and i play with the bypass valve and can get as high as 5 in of hg.
When i apply gas, the vacuum gage goes up, meaning going form 2 to somewhere in the range of 20 in of hg at the same location. This doesn't make sense since i should be producing boost and should be going to 0 at full boost.
I have no mufflers and only a catalytic converter which i purchased 2nd hand.
Question:
Is it possible that i have worn valve guides leading to the low vacuum? I never checked the vacuum prior to installing the supercharger.
Is it possible that i still have a vacuum leak.
The part that gets me is that Vacuum should decrease at the high side, after the supercharger not increase. What the heck is going on.
Try taking the car out on the road and test. Doing it while the car is sitting not in gear or moving doesn't really give you the best readings.
05-16-2018, 09:49 PM
