ahmadhasib

Hello guys! I've recently purchased a 1994 RX-7. I've tried to do some research on the issue I'm having but could not find a detailed answer.

I read on a few threads that boost levels would fluctuate from 10psi to 8, and back to 10 on a stock RX-7. I did not find at what RPM these fluctuations would be happening.

When I am in 3rd gear, I stomp on the gas starting at 1,800 rpm. Here is wgat happens:

3,200 rpm- VERY quick jumps from 0psi to 12psi.
Can also feel a very strong pull at pressure rises.

3,300 to 4,500 rpm- Settles down to 10psi and stays at that till 4500 rpm.

4,500-5,000 rpm - gradually drops from 10psi to 4psi

5,000-6,000 rpm- drops from 4 psi to 0-1psi.

6,000-8,500rpm. Sticks at 0-1psi.

I'm not even sure where to begin looking at what or where the issue can be.

Is this considered normal and correct pressure drops as the RPM increases for a stock RX-7?

Only modifications I know about is Greddy down pipe, Greddy catback exhaust, and K&N drop on filter in stock box.

ahmadhasib

Update: I found the issue. There was a vacuum line where one end was connected to the intake manifold and the other end not connected to anything. I found an open nipple underneath the intake box (looks like it was connected to the air side of the turbo sitting closer to the firewall). When I plugged it in, the car is now holding boost past 4,500 rpm.

Sgtblue

iTrader: (16)

Glad you found the issue. For future reference and a place to start learning about the sequential system, here are a couple links from the 3rd. Generation Section FAQ sticky.......
http://www.autosportracetech.com/RX-...erOverview.htm
https://www.rx7club.com/3rd-generati...tified-841821/

As a new owner that FAQ sticky is a great place to start reading........