163rwhp... But kinda bummed... Huge lean spike!!! - Miata Turbo Forum - Boost cars, acquire cats.

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Old 05-12-2007, 09:09 PM   #1
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Default 163rwhp... But kinda bummed... Huge lean spike!!!

Well... In the name of research it have tried to take little baby steps with my turbo. Adding a few minor adjustments along the way to see what small increments will get you, instead of making one big leap. I can tell you that I am learning stuff and I haven't destroyed anything, but it can get frustrating at times and today was one of those times. Anyway... on to the story.

Here is a link to my first venture to the dyno right after the install:

https://www.miataturbo.net/forums/showthread.php?t=4317

Here are the specs on the particulars:

Originally Installed:
Greddy kit [With the 12:1 disk]
Custom intake
Custom [Jim*] RX-7 intercooler

Installed after the initial "after turbo" dyno runs:
Bipes [Pulling 4* at 3k-4k and 1* per 65* of temp]
Olderguy's O2 Clamp with the original "factory" settings
NGK 7E plugs
VooDoo Manual boost controller

Here's the problem:

The car ran great initially, but I was encountering a little pinging on hot days so I went ahead and installed the Bipes and set it as shown above. In the last few weeks I have installed the plugs, clamp and MBC. The car still runs great and I am still getting no pinging. During the dyno run we got a lean spike all the way up to 17.9 right at about same time that the car is hitting max boost. But it only last for like a second and then richens up as the boost tapers off. [Sorry... I was so brain dead thinking about the lean spike that I forgot to get the dyno files, but I hope to have them on Monday to post and we can analyze them.] Conversely I am also getting a big boost spike that seems to go up to about 10 or 12.

First off I am going to check the dang MBC. I must have it tightened up too much... Sheeze. It is obviously causing the spike in boost and then it drops off dramatically because the Greddy waste gate actuator is so weak. [I need to quit goofing around and get a boost gauge and a real wide band.]

Secondly, I am going to go ahead and install the Walbro 190 hp and the 1.8 injectors. [I was stupid to not have already done this, but I thought that the simple addition of the O2 clamp alone would have smoothed out the fuel for only the little amount of boost that I wanted to increase.]

Thirdly, I am going to either buy a pack of disks for the vortech or either install a MBC on the vacuum line running to the FPR so I can adjust it on the fly.

Fourthly, It's kind of weird that I am getting no pinging with that lean spike.

Fifthly, I am going to quite drinking so much when I work on my car.

Frankly... I can't see where the the O2 clamp is doing anything for me. I think I have it installed correctly. I ran a "T" off of the vacuum line feeding the Vortech. Ran the line through the little hole in the firewall behind the washer bottle. Ran it into the pressure switch. Capped the other side off. Wired the signal from the O2 sensor to the "NC2" plug on the pressure switch. Wired the "CO1" plug back to the ECU, and wired the white wire from the O2 clamp to the "NO3" plug on the pressure switch. I know I have the other stuff wired up right and the LED is on. Maybe if I get the other issued ironed out everything will start to fall in place and the benefit of the O2 clamp will become more evident. Right now the A/F ratio looks like a roller coaster ride.

I thought I was doing so good getting everything installed and running so good, but now I feel like a total dumb *** trying to get the boost right, the A/F right and the whole thing tuned correctly.

Comments, advice, suggestions? [I promise that you won't hurt my feelings or self esteem. ]
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Old 05-12-2007, 09:41 PM   #2
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The O2 clamp helps only when you are in closed loop boost(below 4000rpm). The lean spike you describe and where you describe it(when hitting max boost) sound like your pump has reached it's limit. What boost level were you trying to run? What injectors?
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Old 05-12-2007, 09:56 PM   #3
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Quote:
Originally Posted by olderguy View Post
The O2 clamp helps only when you are in closed loop boost(below 4000rpm). The lean spike you describe and where you describe it(when hitting max boost) sound like your pump has reached it's limit. What boost level were you trying to run? What injectors?
Yeah... I agree. I didn't realize until I went back to the dyno that the lean spike was occurring later in the RPM range. The injectors are stock as is the pump. But they won't be after tomorrow. You are probably right about the pump maxing out. At this point I was only wanting to run about 7-8 psi.
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Old 05-12-2007, 10:12 PM   #4
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1.8 Injectors are borderline 8psi with the 12:1 disc and a decent OEM pump.

1.6 Injectors should not be pushed beyond 6~7psi
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Old 05-12-2007, 10:20 PM   #5
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Originally Posted by olderguy View Post
1.8 Injectors are borderline 8psi with the 12:1 disc and a decent OEM pump.

1.6 Injectors should not be pushed beyond 6~7psi
"Secondly, I am going to go ahead and install the Walbro 190 hp and the 1.8 injectors..."

I assume though, if I do this without installing the 8:1 or 7:1 disk in the vortech that I will then be too rich... Right?
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Old 05-12-2007, 10:47 PM   #6
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no you could pretension the afm or run the MBC in line with the FPR to delay the reaction producing the same results, as a recalibrated FPR. it is worth a shot.
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Old 05-13-2007, 04:54 AM   #7
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Quote:
Originally Posted by 92Black&Tan View Post
"Secondly, I am going to go ahead and install the Walbro 190 hp and the 1.8 injectors..."

I assume though, if I do this without installing the 8:1 or 7:1 disk in the vortech that I will then be too rich... Right?
Correct assumption, unless you do as magna says and stay at LOW boost(5~6). The 12:1 will put you over 100psi at 8 lbs of boost.
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Old 05-13-2007, 06:40 PM   #8
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Originally Posted by magnamx-5 View Post
no you could pretension the afm or run the MBC in line with the FPR to delay the reaction producing the same results, as a recalibrated FPR. it is worth a shot.
You know... I wonder if you would have to use an MBC in the vacuum line feeding the RRFPR. Why couldn't yo use a simple brass needle valve. I mean all you are trying to do is regulate the pressure feeding the RRFPR. I have such a small brass valve in the garage sourced from ACE hardware. Does it need to have a ball and a bleeder?
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Old 05-13-2007, 06:42 PM   #9
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search button is your friend. idea was proposed by yours trully and tested by braineack.
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