Good, I don't want to pull the turbos. I've been putting off a vac hose job because I don't want to open a can of worms with everything currently working so well. I have never removed the turbos and am not looking for a project so I'll stay away from porting the wastegate.

I think I will try and get an electronic boost controller just to keep things safe.

 

Great thread....I'm in a simliar situation with some occaisonal boost spikes...but, other than that the car runs great. I'll keep remembering the "if it ain't broke don't fix it" line when I want to tinker with my FD, too.

 

There really isn't anything wrong with the way your car is running, and you are perfectly safe where you are right now.

If you feel like you must do something, drilling the wastgate pill (if you have one**) would be the simplest most cost effective way to lower your boost. To do this, remove the airbox to get access to the wastegate hose. Remove the hose. Take a Phillips screwdriver of the proper length and diameter and insert it into the hose. Push the pill out the other end. The pill is made of a soft material, and will drill out very easily. Find a drill bit that is ever-so-slightly larger than the diameter of the existing hole. Drill, and replace the pill the same way you removed it. After replacing the pill, look thru the hose to make sure the hole in the pill is not blocked. THIS IS CRITICAL!!!!! If you can see the light , replace everything. Your boost should drop a little.

**If your turbos have restrictors in the nipples, you wont have any pills, and this won't work

 

If you don't ever plan on adjusting the boost, you only want to limit your current spikes; a manual boost controller will work well. EBC's are great if you want to have multiple boost settings like:

OFF - ~7 PSI (stock wastegate spring level)
LOW - 10 PSI
HIGH - 14 PSI

or something similar. If you are only trying to tune back to around 10 PSI, the manual controllers will work just fine (and save you a little money).

 

aftermarket boost control can still vary with the weather. If you really don't plan on modding the car further I just don't see a reason to get one. If you can get the right sized restricter pill in there the factory boost control system will be able to keep things pretty stable, as the factory system is fully closed loop.

 

While I agree on principle, I have not met anyone who was continually adjusting their EBC with the weather. And in my area, we see everything from 110F+ to 0F (or below).

 

It's hard to know what to do. I would really be tempted to do the restrictor pill but I just have not looked into it much. The manual controller sounds simple enough once you get it setup. Kind of wish I had a wideband a/f gauge so I knew if any of this were a concern to begin with. I think my VDO mechanical gauge is probably accurate but I question that as well.

Really glad to have all the pros giving me help.

 

Does drilling the restrictor pill just lower the boost all around or allow the oem system to manage it and keep it at 10? I'm sorry if that is an ignorant question. I am just wondering if it just generally lowers the boost would I be able to make 10 psi when it's hot outside.

I just read the FAQ post regarding restrictor pills. It didn't really make me want to dive into it. I have much to learn about the FD turbo system. I really just want to not worry about it like AdamC and Arghx are suggesting but my only concern is that it's 70 outside and I'm afraid when it's 50 I'll get into fuel cut territory. I'd rather be overly careful at this point than have to rebuild an engine.

 

http://www.autosportracetech.com/RX-7/faqs.htm#Pills

If I were you, I'd go to a hardware store and buy a few welding tips of various sizes to try, and not drill out the factory pill at all. Here's a welding tip chart: http://bikesmithdesign.com/Welding/Tips.html . It'd be faster and cheaper than installing and tuning an electronic boost controller on a car that is basically stock...


Well it depends. The more boost you are trying to run relative to the spring pressure, the less stable a boost control system tends to be as weather changes. It also depends what you are measuring boost with. It's a lot easier to notice variations in boost control when you are taking logs through something like a Power FC than when you look at slow responding digital displays or buffered mechanical gauges.

 

I would wager that if you need to log it to notice it, it's probably not really going to affect the average Joe all that much.

 

Can anybody attest to the accuracy of a mechanical boost gauge, more specifically a VDO? AdamC I think you have or had a VDO mechanical guage. Does it jive with boost readings on your powerFC?

 

On an FD with sequential twins it is a little less of a concern. High boost 4 cylinder applications with internally wastegated single turbos tend to have the most problems with spiking and fluctuation with the weather.

That's a complicated question... every gauge has to be referenced to an instrument, and that instrument is referenced to ambient atmospheric pressure. So it all depends what you are measuring it against. The default calibration for the stock MAP sensor on the Power FC usually reads low.

 

Drilling the pill lowers boost. Simple as that. This assumes you have restrictor pills. Its easy to do, costs nothing, and won't clutter your stock interior with something you don't want (EBC). Drill the pill. If you are not satisfied, you can always get a boost controller later. Just don't drill the pill very much. Too much, and you may not even make 10 psi.

My VDO boost gauge shows exactly the same as my pfc.

 

I have the same 12psi boost. All I have is an HKS downpipe. I ported my wastegate so I'm not worried. Even my airbox is all stock.

 

Did porting your wastegate do anything for you? Pretty sure boost creep is not a problem for either of us since we're both using the stock airbox and stock muffler and main cat.

 

I added downpipe and ported my wastegate when I put in a new engine. Before things were all stock with a 10-8-10 boost pattern. While my engine was out, I asked the experts on this web page about preventive maintenance. bdfd_3s said that I should port my wastegate for peace of mind. So I did. Still don't know while my boost is around 12psi. Just makes me feel better knowing the wastegate is larger to keep the boost under control.

 

Why are you comfortable running 12 psi? According to many on this site you are right on the edge of engine trouble if your ecu is stock. That is what this whole thread is about.

 

Just want to make sure I got the right hoes & pill...

My 1/16" bit went through it and removed a tiny bit of material. I thought that was a little strange because the original hols is supposed to be .062" right? So the 1/16" bit should have slid in without any drilling necessary. I might drill it with a 5/64" but that comes out to .08" and I'm not sure if that is too big.


If this looks right please let me know. If I need to get a drill bit in between .06 and .08 I can do that. I don't think the 1/16" bit really did anything at all but it did make a few tiny dust shavings.

 

1/16th is .0625. Not much bigger than the original hole. The pill material is very soft. I would run the same bit a couple more times just to smooth it out, then reinstall it. You should see your boost drop slightly, which is what you wanted

A maximum of 11 psi should be ideal.

 

Thanks Adam. I would love to end up at 11 psi. Do you think a difference of .0005" will accomplish anything? It just seems like such a small amount. 5/64" is definitely way to big.

Here is a drill bit chart in case somebody else goes down this road.

1/16 .0625
52 ... .0635
51 ... .0670
50 ... .0700
49 ... .0730
48 ... .0760
5/64 .0781

http://www.thedirtforum.com/conversions.htm

I'd like to try a #52 or #51. I'll post my results.

 

Run it thru the hole several times until the bit doesn't fit so tightly. That should do it.

 

Drilled the restrictor pill with a #51 .067" drill bit. Took the car for a highway spin, here are the results. I was somewhat limited on how fast I could drive. I couldn't really check boost on the secondary turbo in 4th or 5th.

On primary turbo in 2nd and 3rd it boosts to 12. In 4th and 5th WOT at about 60-70 mph I still get 12 psi. I think that would still be on the primary in those gears at that speed.

I did a 3rd gear run from 40mph to 120mph. Boost was 12-8-10 but tapered off to 8.5 or 9 max at 6000-7000 rpm. Drilling the pill seems to have worked for secondary turbo boost that is too high. I think I may have drilled it out a little too big.

Does the restrictor pill not effect boost on the primary turbo? Bottom line at this point is that I'm still hitting 12 psi easy on the primary in 1st through 3rd. I don't know what primary boost would be in 4th or 5th since I can't drive that fast.

 

Agreed, and if you go with a simple ball & spring check valve with adjustable spring tension vs the simple adjustable valve that most manual boost controllers (MBC) consist of, it'll allow the turbos to spool up faster. And if you're too lazy to make your own, you can always get one already made.

 

12 psi on the primary won't hurt anything because the stock fuel system will plenty of fuel at low rpm. On a stock car, boost will tend to drop off a little at high rpm in higher gears. Sounds like your problem is solved.

BTW, you cant go 120 mph in 3rd gear

 

The primary has its own actuator (precontrol actuator) with its own solenoid and pill. The secondary boost tapers off a little bit up top from the factory. Your secondary boost sounds fine to me. Just about every factory turbo car tapers boost a little bit near redline.