Smog air pump removal and midpipe
 

After my air pump seized and failed, I removed it and did the drive pulley and belt change. I also replaced the cat converter with a Bonez resonated mid-pipe. To guard against the chance of max boost creep, I installed a GReddy pop-off valve (14 psi) on the hard pipe just before the GReddy elbow. I was expecting some change in performance, but the turbo spool-up, throttle response and increase in torque are all much better than expected. I have not yet done any (measured) acceleration runs or put it on the dyno again, but the car feels 10-15% faster. Has anyone else done the air pump-mid-pipe switch and had similar results?

You'll definitely gain some power due to removing a huge restriction in your exhaust system, not to mention your boost has probably went up as well. Keep an eye on the boost and make sure that pop off valve is doing it's job ;)

air pump and cat removal
 

Goodfella- yeah the boost creep was a major concern. I asked Brian at Rotorsports, who did the engine and set the fuel maps on the Apexi PFC, about porting the waste gate and his opinion was that was not needed if the PFC was working OK. I added the pop-off valve to allow me to sleep better, since I am on my third engine. I calibrated it to relieve pressure at 13 psi. I am still trying to jury-rig my pressure testing system to calibrate the popoff valve with my boost gage and the electronic boost sensor all on one test to make sure they are all within 0.5 psi

hey, great info... so what pulley did you guys use (or recommend) after removing the smog/air pump? and what about the ACV hookup? leave it disconnected or plugged? I'm thinking about doing this setup when I get a PFC and HKS EVC ... just want to know what to look out for.

update:

instead of the typical aftermarket under drive pulley set that "could" lead to potential engine bearing damage because it doesn't fit right, what idler pulley is recommend??

Any difference between that and this kit? http://www.pettitracing.com/rx7/index_performance.htm

petit is $30 cheaper.

Are you talking about a regular blow-off valve?

I dont believe he is. It is a saftey device that works exactly as it's name implys. To help keep his engine from blowing up due to boost creep, presumeably because he has not ported his wastegate.


John

That what I thought he was saying but when I google greddy pop off vavle, it just shows Blow-off valves, so I'm a little confused.

To my knowledge, Pettit doesn't sell an Idler pulley for airpump removal. They do sell a Billet Pulley to replace the Power Steering Idler pulley.

I think this is it

http://www.racingworks.com/greddy_relief.htm


John

I can't link directly to the product, so here's copy/paste:

Air Pump Eliminator/Delete Kit RX7 FD - (Silver)
Eliminate your stock air pump and free up some wasted horse power! Most stock air pumps are now approximately 15 years old and are no longer working properly. Please specify if you have a stock main pulley or power pulley this will determine which belt size you need. Fit’s all 93-95 Mazda RX7 FD models.
Price: $149.00

http://www.pettitracing.com/rx7/imag...irpumpelim.jpg

That's not an idler pulley kit. That's just a billet version of the Greddy airpump kit.

https://www.rx7club.com/showthread.p...ghlight=pulley
https://www.rx7club.com/showthread.p...ghlight=pulley
https://www.rx7club.com/showthread.p...t=idler+pulley

^ Awesome info !!! More to read!!

and I just found this old group buy which is closed, but anyone who got one of these say how well its working?

https://www.rx7club.com/group-buy-center-69/tweakit-racing-air-pump-deletion-idler-pulley-kits-882388/

I swear, I need to stop working so much and spend more time reading the forum... I hate missing stuff like this.

I guess most people got the single turbo setup, Im still running twins though.