RX7Club.com - Mazda RX7 Forum

RX7Club.com - Mazda RX7 Forum (https://www.rx7club.com/)
-   3rd Generation Specific (1993-2002) (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/)
-   -   My personal sequential boost thread, from broke to hopefully fixed (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/my-personal-sequential-boost-thread-broke-hopefully-fixed-988242/)

supraturbo1987 03-21-12 09:44 AM


Originally Posted by Mrmatt3465 (Post 11024880)
Trev,
It appears you've made some good progress! Even the most perfect of rx7s always seem to have hidden issues. I picked up my 93 touring with 38k on it. Upon installation of my boost gauge I discovered I was only hitting 5 psi in first and a every-now-and-then transition in second. Third had a slow transition. As I was tearing into my engine bay to replace my vacuum lines and install Azeknightz solenoid rack, I ended up replacing a lot of things! I wish I could have seen your thread a few days ago and I would have suggested testing your omp nozzles while you were there. Both of mine had failed check valves. After buttoning up including the installation of a nice 3" Pettit downpipe, I got full boost an transition in all gears. I do however now have a 13-8-10 boost pattern. I attribute the spike to the 3" downpipe. My plan to quell that spike is the dual MBC set up as suggested by I believe it was Damien. You can find the link in the FAQ. I believe dual MBCs will trump a single ebc in terms of full control over transition. I'm a set it and forget it kind of guy :).

Good luck to you!


Thanks for the info. I guess I am not aware of check valves in the omp

supraturbo1987 03-21-12 09:49 AM


Originally Posted by Mrmatt3465 (Post 11024880)
Trev,
It appears you've made some good progress! Even the most perfect of rx7s always seem to have hidden issues. I picked up my 93 touring with 38k on it. Upon installation of my boost gauge I discovered I was only hitting 5 psi in first and a every-now-and-then transition in second. Third had a slow transition. As I was tearing into my engine bay to replace my vacuum lines and install Azeknightz solenoid rack, I ended up replacing a lot of things! I wish I could have seen your thread a few days ago and I would have suggested testing your omp nozzles while you were there. Both of mine had failed check valves. After buttoning up including the installation of a nice 3" Pettit downpipe, I got full boost an transition in all gears. I do however now have a 13-8-10 boost pattern. I attribute the spike to the 3" downpipe. My plan to quell that spike is the dual MBC set up as suggested by I believe it was Damien. You can find the link in the FAQ. I believe dual MBCs will trump a single ebc in terms of full control over transition. I'm a set it and forget it kind of guy :).

Good luck to you!


Thanks for the info. I guess I am not aware of check valves in the omp nozzle lines?? I guess I will probably end up with dual mbc as well to bring the primary boost back down to 10. Still not sure why I have a 6 psi dip instead of 8. All of my rats nest solenoids tested perfect and have only 8k. Miles on them. Also, my two green turbo control solenoids on the front of the manifold tested fine as well. Too bad I just bought the new WG and Turbo PC lines with pills in them if I am going to go mbc.

Mrmatt3465 03-21-12 09:57 AM

The check valves are built into the OMP nozzles. They are in place to allow oil metering under pressurized [boost] conditions. A simple test on them is the "blow both ways" test. Even at 38k miles, both of mine had failed! It is DIRE that these check valves be operational as they are imperative to the proper metering of oil via your OMP. If the valves are failed, then under pressurized conditions the motor will simply spit the provided oil back through the breather and into your primary turbo inlet pipe. Have you noticed oily film in your intercooler piping? :) I personally replaced my nozzles as they were I believe $40 for both. However in the future, should they fail again I plan to run one of DaleClarks fancy check valves tee'd to both nozzles externally to achieve the same effect.

Back to being on topic, most people suggest that adding a downpipe will NOT attribute to any boost issues. In my case I have noticed a spike on the primary turbo and have decided to get independent MBCs for each turbo [primary and secondary]. This will provide a full control over the sequential operation.

supraturbo1987 03-21-12 01:24 PM


Originally Posted by Mrmatt3465 (Post 11025104)
The check valves are built into the OMP nozzles. They are in place to allow oil metering under pressurized [boost] conditions. A simple test on them is the "blow both ways" test. Even at 38k miles, both of mine had failed! It is DIRE that these check valves be operational as they are imperative to the proper metering of oil via your OMP. If the valves are failed, then under pressurized conditions the motor will simply spit the provided oil back through the breather and into your primary turbo inlet pipe. Have you noticed oily film in your intercooler piping? :) I personally replaced my nozzles as they were I believe $40 for both. However in the future, should they fail again I plan to run one of DaleClarks fancy check valves tee'd to both nozzles externally to achieve the same effect.

Back to being on topic, most people suggest that adding a downpipe will NOT attribute to any boost issues. In my case I have noticed a spike on the primary turbo and have decided to get independent MBCs for each turbo [primary and secondary]. This will provide a full control over the sequential operation.


I don't have it in me to tear this apart again right now to check those omp nozzles, but will soon. I am going to just do the MBC that Damian did and go that route. I may try the home depot method, an if that doesn't work well, I will get what he described.

Trev

DaleClark 03-21-12 03:53 PM

Glad to hear you have boost!

With too much on the primary turbo you may have something going on with your factory boost control. I assume you have the pills in the lines, they're installed right and not plugged or anything, lines are tight with no air leaks? Also, make sure the plugs going to the boost control solenoids aren't swapped, it's easy to do and does weird stuff.

Of course, a manual or electronic boost controller will get around all those problems :).

Dale

supraturbo1987 03-21-12 05:54 PM


Originally Posted by DaleClark (Post 11025526)
Glad to hear you have boost!

With too much on the primary turbo you may have something going on with your factory boost control. I assume you have the pills in the lines, they're installed right and not plugged or anything, lines are tight with no air leaks? Also, make sure the plugs going to the boost control solenoids aren't swapped, it's easy to do and does weird stuff.

Of course, a manual or electronic boost controller will get around all those problems :).

Dale

Dale,

The two boost lines that have the pills are brand spankin' new. I have them installed so that the pill is closer to the turbo compressor housing on each line. I am certain my turbo control solenoids are plugged in perfect. I really think that the DP is having something to do with it...

All lines are secure and triple checked.

Trev

Mrmatt3465 03-21-12 05:58 PM

Surprisingly enough you won't need to tear into you UIM to test your omp nozzles :) On your primary TIP (turbo inlet pipe) there are two nipples, one of which is the breather side of your OMP nozzles! If you follow your vacuum diagram you can find it. If you can blow through the hose and not suck through it, you're in good shape :) if not, add a check valve to that line and you'll be golden. On the note of omp lubrication, premixing is always a good idea.

Matt

supraturbo1987 03-21-12 08:29 PM


Originally Posted by Mrmatt3465 (Post 11025663)
Surprisingly enough you won't need to tear into you UIM to test your omp nozzles :) On your primary TIP (turbo inlet pipe) there are two nipples, one of which is the breather side of your OMP nozzles! If you follow your vacuum diagram you can find it. If you can blow through the hose and not suck through it, you're in good shape :) if not, add a check valve to that line and you'll be golden. On the note of omp lubrication, premixing is always a good idea.

Matt

Great info Matt! Thank you! I will stay awayfrom premix for new just for the smell reasons and the fact my wife wants to drive with me and she is not a fan of that lawn mower smell :)

adam c 03-22-12 09:14 AM

Trev,

A manual boost controller on your wastegate line should allow you to lower your boost to where you want it. Adding a controller to the prespool line complicates things dramatically. I would leave the prespool line alone (experience speaking).

A 3rd gear pull (rather than 2nd) is normally a better way yo test your boost. 2nd gear happens so fast that the control system doesn't get a chance to take over as well as 3rd gear. I would test in 3rd before doing anything.

supraturbo1987 03-22-12 09:37 AM


Originally Posted by adam c (Post 11026426)
Trev,

A manual boost controller on your wastegate line should allow you to lower your boost to where you want it. Adding a controller to the prespool line complicates things dramatically. I would leave the prespool line alone (experience speaking).

A 3rd gear pull (rather than 2nd) is normally a better way yo test your boost. 2nd gear happens so fast that the control system doesn't get a chance to take over as well as 3rd gear. I would test in 3rd before doing anything.

Adam,

Thanks for the advice, I appreciate it. I did forget to mention that I did do some third gear pulls and achieved the same results as IIRC. I will try again today though an see my results. Taking a look at Damian's thread on the Hallman MBC, he put a controller on both and seemed to be able to dial it in nicely. Are you thinking just leave the PC factory line with the pill in it connected, then just use the Hallman for the WG and start there? I could see that being a good plan, save me a little $$$ for a second MBC. If it works, then I know I don't need to proceed further.

Trev

adam c 03-22-12 02:36 PM


Originally Posted by supraturbo1987 (Post 11026450)
...... Are you thinking just leave the PC factory line with the pill in it connected, then just use the Hallman for the WG and start there? ......

Yes

supraturbo1987 03-22-12 03:18 PM


Originally Posted by adam c (Post 11026835)
Yes

Real good, kind of my thought as well. Thanks!


All times are GMT -5. The time now is 04:08 PM.


© 2024 MH Sub I, LLC dba Internet Brands