Microtech S4 N/A with LT10s - Odd High RPM Vacuum readings
#1
S4 N/A with LT10s - Odd High RPM Vacuum readings
Hey everyone,
I have an '86 GXL that I put an LT10s into, and finally was able to take it to be tuned on the dyno today. All went well, save for some really odd vacuum readings high in the RPM range. As you can see on the Dyno graph, the curve was nice and steady then suddenly went all over the place and the pressure readings from the microtech went up and down wildly:
Now, I've taken the BAC out and I'm drawing the microtech vacuum line straight from that location. Here is what I was thinking: As the pressure readings are out of whack, is it that this location is inefficient to draw vacuum from at high RPM? Where is a good place to attach the line to on an S4 N/A intake? Or is the S4 intake simply not efficient past "X" RPM? Or am I way off base with all of this?
Kind of an odd thing....
Any thoughts?
I have an '86 GXL that I put an LT10s into, and finally was able to take it to be tuned on the dyno today. All went well, save for some really odd vacuum readings high in the RPM range. As you can see on the Dyno graph, the curve was nice and steady then suddenly went all over the place and the pressure readings from the microtech went up and down wildly:
Now, I've taken the BAC out and I'm drawing the microtech vacuum line straight from that location. Here is what I was thinking: As the pressure readings are out of whack, is it that this location is inefficient to draw vacuum from at high RPM? Where is a good place to attach the line to on an S4 N/A intake? Or is the S4 intake simply not efficient past "X" RPM? Or am I way off base with all of this?
Kind of an odd thing....
Any thoughts?
#2
Engine, Not Motor
iTrader: (1)
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,789
Likes: 0
Received 108 Likes
on
91 Posts
It looks like you may be experiencing noise. How is the system grounded? Is the CAS connected with the shielded cable that came with the Microtech harness and what condition is the connector?
Pulling vacuum from the dynamic chamber may not be the best place. Try taking it from the same place as the stock pressure sensor.
Pulling vacuum from the dynamic chamber may not be the best place. Try taking it from the same place as the stock pressure sensor.
#4
It looks like you may be experiencing noise. How is the system grounded? Is the CAS connected with the shielded cable that came with the Microtech harness and what condition is the connector?
Pulling vacuum from the dynamic chamber may not be the best place. Try taking it from the same place as the stock pressure sensor.
Pulling vacuum from the dynamic chamber may not be the best place. Try taking it from the same place as the stock pressure sensor.
Where is the stock Vacuun pickup point?
Thanks for the help guys!
#6
When you say that the inlet system has become a restriction - what do you mean by the "inlet system"? The nipple that the tube is plugged into, the actual filter that's sucking in air, or the whole intake?
Thanks!
Trending Topics
#8
Engine, Not Motor
iTrader: (1)
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,789
Likes: 0
Received 108 Likes
on
91 Posts
The 2nd gen also has a small pill in the boost sensor line, probably for this purpose as well.
The dynamic chamber is designed to exploit pressure waves from the opposing ports and intake reversion. Personally I would not pull vacuum from that point as it will be very turbulent (and run into about 2 PSI of "boost" at high RPMs).
As mentioned, a pill in the line will help greatly.
The dynamic chamber is designed to exploit pressure waves from the opposing ports and intake reversion. Personally I would not pull vacuum from that point as it will be very turbulent (and run into about 2 PSI of "boost" at high RPMs).
As mentioned, a pill in the line will help greatly.
Thread
Thread Starter
Forum
Replies
Last Post
jetlude
Single Turbo RX-7's
4
08-18-15 04:53 PM