TB Hole size - MS4 Cam, IAC maxxed out
10-11-2007, 12:05 AM
#1
On The Tree
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TB Hole size - MS4 Cam, IAC maxxed out I measured the stock hole to be a 5/32" diameter size. I tired the method of adjustin the set screw, and it appears as if I'm out of range of the reset. I was able to move it maybe 4-5 degrees, then the TPS failed to reset to 0.0 after that. On cold starts my IAC is maxxed out. After its all warmed up its back down to 65 steps.
Area wise I looked at a few options.
Stock 5/32" hole area is: 0.01917 sq inches.
If I used the next size up in my box, which is 11/64", and drilled the stock hole larger I compared the areas. The new area would be 0.003201 sq inches. That is an increase of 21%, which seems too much.
I was thinking maybe an increase of 10-15% area to start with. To obtain this, I figured it would be necessary to drill a seperate hole, and leave the stock one alone.
If I drill a 1/16" hole seperately, I get an increase of 16% total area. Granted this isn't considering the differences due to effective area, but it gives me an idea.
What does everyone else think?
Thanks,
Kevin
Area wise I looked at a few options.
Stock 5/32" hole area is: 0.01917 sq inches.
If I used the next size up in my box, which is 11/64", and drilled the stock hole larger I compared the areas. The new area would be 0.003201 sq inches. That is an increase of 21%, which seems too much.
I was thinking maybe an increase of 10-15% area to start with. To obtain this, I figured it would be necessary to drill a seperate hole, and leave the stock one alone.
If I drill a 1/16" hole seperately, I get an increase of 16% total area. Granted this isn't considering the differences due to effective area, but it gives me an idea.
What does everyone else think?
Thanks,
Kevin
10-11-2007, 06:31 AM
#3
Staging Lane
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From what I hear you can go up to 1/4" hole. I'm guessing you are having some idle problems. I hear a lot of guys saying they get this cam to idle great, so you might do some research on tuning some other things, spark advance, adaptive idle routines, etc.
04-29-2008, 04:36 AM
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There is no need to ever drill the TB blade. Get the TB blade pitch and desired airflow tables (along with fuel spark etc) set correctly and a MS4 and MS3 will idle quite nicely around 750 RPM.
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04-29-2008, 06:25 AM
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If your on limited funds send your pcm for a mail order tune to TSP i guarantee it will run fine when u get it back. If you want to just make it to a dyno shop an easy fix ive seen is just take the tube off the bottom of the intake manifold thats part of the pcv. You will have a huge vacuum leak there but it will run and idle to get u where u need to go. Theres a video on youtube if you find one that says ms4 chop compilation that will show what im talking about.
, the reason it probably wont idle down past 900 is the big hole in the TB blade 