FD 13B-REW BASIC MODS:

Aspect Turbo Kit;
Garrett GT3582R T3 1.06 AR turbine on a short runner exhaust header.
Compressor upgraded to Force Performance HTA billot 82mm making it a FP HTA GT3582R Ball Bearing Turbocharger. Done in 2014.

RX-7 store SS MP.
Racing Beat cat back.
Stock intake ports and medium exhaust ports. Intake ports are port matched and internally enlarged and polished.
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BASIC PROBLEM with Tial F46 wastegate. 14 years old.
Blitz Dual- SBC Spec R boost controller. 20 years old.

Gain was 30. This was used for all 4 boost setting. It would very slightly over boost to give maximum spool up.

Ratios for boost levels control were:
20 -> 12 psi.
29 -> 14 psi.
37 -> 16 psi.
47 -> 18.3 psi.

The Blitz keeps boost confined to its singular P row in the PFC control tables. It is very linear.
This unit has feedback control that works even when the weather changes from summer to winter. It does not need seasonal changes.

Lately I noticed boost was behaving differently while I was re-tuning 18.3 psi. I am going from water/meth injection back to only water injection and to a richer 10.8 AFR.
With the 47 ratio, it is initially over-boosting to about 20 psi causing the Blitz over-boost control to reduce the ratio by 3. After all this settled down boost would flat line around 19 psi.
I moved the ratio down from 47 to 44 and reduced the gain down to 15.
This caused the flat-line boost to drop to around 18.5 psi, but the initial over-boosting still happens. I then log runs using gains of 5, 10, 15.
Over boosting has reduced but very little.

I logged 16 psi and it over boosted to 17 (never did this before) but kept 16 psi across the rpms.

Thus the ratio control of boost level is working but gain control over spool up is barely working. I did check the plumbing for the WG and EBC and it is all OK.
So the problem is either the EBC or it solenoids, or the WG diaphragm is leaking, or all three?


What is the normal lifetime for a WG?

 

What does it do when you turn off boost control and run off the spring?

 

I did not do that as it would require removing connectors which are not easy to get to. The solenoid pack is under the anti lock brake controller and the EBC unit is in the dash. I can do this test this weekend.

I did try a gain of 1 and it still over boosted as before.

 

I have a switch on the dash to cut power to the boost solenoid. Works to cut boost in heavy traffic, and as a test.

 

HI Chuck,

nice to see you still posting. Club members, Chuck is easily in the top 5 members of this board in terms of adding value and helping others... as well as one smart guy.

(don't know him personally, he's probably beats his dog) just kidding.

"problem is either the EBC or it solenoids, or the WG diaphragm is leaking, or all three?"

of course you are correct but most probable is something going on w the WG. most of the other components are electronic.

"What is the normal lifetime for a WG?"

first off, wastegates function in a hellish enviornment. the valve stem is being assaulted by 1700 F with carbon thrown in. then there is the silicone diaphragm whose lifespan directly relates to how close it is to the exhaust tubes.

since it appears that your biggest problem is a spike at boost onset and then it tapers off a bit my bet is a (small) mechanical issue w your WG.

if this is the case, you should still have the problem if you, as Viccor suggests, turn off the Blitz

 

After thinking about it last night and how the WG seals both sides of the diaphragm. The side port is the one to most likely to leak as the valve stem has to slide up and down
through a piece of metal just like a piston. This is the place of most wear which would cause a pressure leak. This leak would require more pressure to overcome the leak and to finally
start opening the valve to reduce boost pressure. The top port is used to regulate the maximum pressure by pushing back against the valve opening. That is why the boost will finally
stabilize at the desired pressure.

If my theory is accurate, testing with only spring pressure should result with a higher than normal boost.

I will do this test this weekend and will get back with you all.

 

If you're implying the valve side of the diaphragm is airtight and pressure only bleeds off when wear occurs in the guide or the valve stem, that's not the case. Brand new WGs bleed off a lot of air in the clearance between the stem and the guide.

 

Maybe, maybe not? Testing will tell. The Tial F46 has an "O"ring seal on the top of the valve stem that seals between it and the bottom of that area.

 

This morning I logged a third gear run from 2000-6000 rpm with an air temp of 39C with the EBC turned off.
The WG spring is 10.153 psi.
Results are normal for running off the WG spring only.
3600 rpm - 9.6 psi
4800 rpm - 10.6 psi
5200 rpm - 10.9 psi
5600 rpm - 10.9 psi
6000 rpm - 11.0 psi

Thus the WG is working normally off the spring only as it did not over boost.

 

It would seem unlikely that the actual electronics would be the problem.

How does your boost controller sense boost pressure? Could there be a leak or restriction?

What about the boost control solenoid?

About a year ago we had issues and it worked OK with the boost control switched off. I first found the MAC boost control solenoid was crudded up on the inside. I swapped it out and alleviated the over-boosting.

I have to add though, the issue came back the next time we were at the track, and it turned out the set screws that hold the wastegate valve to the diaphragm had come loose.

So, I think the set screws had started to come out and the solenoid wasn't able to keep up. Replacing the solenoid allowed the system to compensate until the underlying issue got worse.

 

How does your boost controller sense boost pressure? Could there be a leak or restriction?
It has a built in map sensor and I did check the hoses and connections. It did use a restrictor but I remove it with no changes logged.
I had installed the restrictor because the map sensor original over reacted a little.

What about the boost control solenoid?
I plan to take it out and clean the valves. A friend with the same brand of EBC is going to give me his exact same solenoid for my testing.

This last week in Houston has had high 90's air temps with high humidity so it is miserable to work on the car in my non A/C garage.

 

Took out and apart the dual solenoid unit. It tested to have a slight flow problem.
After cleaning and testing, it seemed to flow like a newer low mileage unit that a friend loaned me.
Testing today: it did work better but is still initially over boosted too much for my liking. Recovery was better.
I will run one more test with a lower gain later this week.

This Blitz Dual - SBC Type R was made back in 1999 for the cars at the time.
Maybe its logic can not handle the new quicker responding turbos on a rotary engine.

 

What has changed? If it was able to control boost before, why wouldn't it now?

If you are having to change your settings from where they were to maintain the same boost, then you are probably compensating for something.

I'd say to make sure your over boost safety settings are appropriate, and keep a close eye on it .

If there is something else wrong.

It will get worse.

 

I had always used a high gain to slightly over boost (about .5 psi) to increase spool up.
As boost increased, less ratio was required to make more boost.

From an earlier post:
Ratios for boost levels control were:
20 -> 12 psi.
29 -> 14 psi.
37 -> 16 psi.
47 -> 18.3 psi.

The three lower settings are still working to control boost but they are over boosting initially..
My 47 ratio for 18.3 psi started giving me high 19+ psi .This also made the over boost protection turn on as it is set at 19 psi.
I have turned the gain down to 5 from 30 and the ratio down to 44. It is still initially over boosting to 19 psi with a final boost in the mid 18s.

Originally the 2 boost pressure sources for the WG and EBC were both taken from before the TB and after the IC. I changed the WG side port
to the turbo out last week. This makes it sense a higher pressure than the top which comes from the solenoid.
The IC does cause a boost drop on turbo output.

Originally I was running 425 cc/min 50/50 water-meth with a 1.4 gal/hr jet into the turbo and 5 gal/hr jet into the IC outlet at 18.3 psi boost and 11 AFR.
The changes were to 100% water at 425 cc/min, with a 2.8 gal/hr into the turbo and the 5 gal/hr into the IC outlet with an 10.8 AFR.

Started tuning and with each run boost control got worse and worse.

All has been checked/verified except the EBC unit itself.
Going to ask my friend to also loan me his newer Blitz EBC.

 

I'm questioning why you aren't doing this on a standalone at this point. It would give you a lot more data to overlay and identify issues faster.

There are more control strategies with drivability to help spool faster and also make the car more drivable.

 

The ECU is an Apexi PFC.
The EBC is a Blitz D-SBC with a R type solenoid.

So: what is your question/concern?

 

Ancient technology. It's not bad, there are simply better ways to do things these days that won't break the bank.

 

So basically whenever you run into an issue, even if its ecu or boost control unrelated, change the system to the latest and greatest..

 

No, you should tear it all out, check vacuum and boost lines, and restore the system to the best of your abilities first. Once that's gone through all of this should be fixed.

A smarter way to control boost, water/meth, or anything auxiliary to a basic setup is when it's integrated directly to the ECU that's controlling the engine and the sensors are able to communicate between each other to compensate.

 

”Tear everything out” is the method by which a person uses when they lack the ability or knowledge to troubleshoot.

 

In this case I would recommend tearing out the old boost controller and going with ecu controlled boost. Also, rebuild the wastegate.

No reason to mess around with the old stuff. It's done it's job if you've had it for that long.

 

Going by millennial logic: Being that the FD is so old school and outdated, I should go out and buy a Porsche!
Now I just need to sell off some retirement investments which most millennial do not have.

Ha Ha, humanity sucks!

 

I don't think anyone is saying that. You are having boost control issues. Today, there is little reason to use a stand alone boost controller. The one from 1999 you have only exists because common/affordable ecu's from that time period didn't have the functionality they have today. There are also lots of instructions now for how to control boost effectively with a PFC.

I'm no millennial, I used to think boost controllers were the coolest things (had a Greddy project b, and an HKS controller too. "Fuzzy Logic" and adjustable gain for the win haha. Over the last 5 years, there is no longer a need for a completely separate system.

 

If you're located near me, or one of my friends, I can send help. TwinChargedRx7 and myself are on the same thought process here and while it may seem like we are tearing you down, it's not the intention. The idea being that integration has it's values since everything is fully communicating to each other. Older stuff works, yes, but you're trying to diagnose something that likely has 20+yr old fittings, lines, etc at best. Tear it out and restore it. It's gotta be something simple.

 

Finished installing another Blitz EBC (different model) with low mileage that uses the same dual solenoid pack.
It was a gift from a friend.
Problem fixed!