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-   -   Lean, why? (https://www.miataturbo.net/prefabbed-turbo-kits-3/lean-why-33464/)

Laur3ns 04-02-2009 04:17 AM

Lean, why?
 
2 Attachment(s)
So, I'm sort of lean in boost. So either
1) My new 3" flows so much better, I just need more fuel
2) My fuel system is dying
3) Something else?

Things changes so far:
- 3" full exchaust with new CAT.
- EBC ripped and MBC in
- new wastegate actuator (more psi)

So?

I did a small VE analyse and this came out:
(OLD vs NEW)

Laur3ns 04-02-2009 04:18 AM

Notice how 183kPa@3400 has increased from 83 to 95 already. And the analyzer was just at the normal setting. What's going on?

Savington 04-02-2009 04:28 AM

I've seen a car leaned out a full half point going from a stock exhaust to an Enthuza 3". If you bumped the boost at the same time, a retune is probably in the cards.

ThePass 04-02-2009 04:31 AM

Well, first of all if you changed the setup, it's perfectly normal to need to retune.
When I went from my 2" cat/2.25" exhaust to the current 3" exhaust I had to retune the whole table for the new setup.

Also consider, if you changed the boost, you may be in fuel cells now at max boost that you were not in earlier - these cells may not be tuned because you weren't hitting them before thus not tuning them. You need to tune them.
The larger exhaust means faster spool. This means that you get higher in the fuel table earlier - again, an area of the VE table you weren't hitting before, so new cells that have yet to be tuned.

If you change anything that alters the behavior of the air pump that is your motor, you will need to re-tune the fuel to have correct AFRs.

-Ryan

ThePass 04-02-2009 04:33 AM


Originally Posted by Spookyfish (Post 389823)
Notice how 183kPa@3400 has increased from 83 to 95 already. And the analyzer was just at the normal setting. What's going on?

You needed a ton more fuel there. It's pretty straight forward.

Laur3ns 04-02-2009 04:53 AM

1 Attachment(s)
So how lean? Did some logging:

Laur3ns 04-02-2009 05:01 AM

Re-tune already planned for mid-April.

full half point
A full half? 1.5 or .5?

Max boost has not increased, around 1 bar/15psi still - just more stable thanks to MBC and the new can. But I am probably higher up in the VE table sooner. I will keep a low until it's tuned.

Should I have them check fuel pressure just to be safe or something? What should they check around 90 PSI at baro if I remember?

ThePass 04-02-2009 05:39 AM

Don't quote me on this but I thought stock fuel press was in the 40's not 90 unless you are running a FPR on top of those 550's.

Laur3ns 04-02-2009 05:48 AM


Originally Posted by ThePass (Post 389833)
Don't quote me on this but I thought stock fuel press was in the 40's not 90 unless you are running a FPR on top of those 550's.

No I'm not running one anymore. Need someone to chime in here.

Braineack 04-02-2009 09:41 AM

stock pressure is 35psi at idle and around 48psi at atmospheric unless you have a 99+


more power equal requires more fuel, if you added a 3" exhaust and raised your boost you are making more torque and need more fuel to support it. looks like you went to 15:1 when you hit 180kPa (11psi) so like, add fuel.

Laur3ns 04-02-2009 09:54 AM


15:1 when you hit 180kPa (11psi) so like, add fuel
Yea I noticed... will do some VE analyzer runs

Braineack 04-02-2009 10:05 AM

i would start by adding 10-15 points on everything in the 156-180-212-230 rows, let MLV remove fuel as needed.

hustler 04-02-2009 10:10 AM

why is your shit lean? Because Jesus cries when you look at men and touch yourself. Make sure you have MS and MLV configured for the correct WBO2. I've fucked that up before.

Laur3ns 04-02-2009 11:46 AM

I'm MLV-ing my ass off and the AFRs are getting back in shape. I added a heap up top and having MLV shave it off. Thanks for all the feedback.

magnamx-5 04-03-2009 01:09 AM

for future reference if you start abit past where u think u should be and shave down u run into the perfect ratio with alot more safety :D

Laur3ns 04-04-2009 05:10 PM

2 Attachment(s)
So, MLV has done it's job, the car is in much better shape. Now that I've added alot more fuel (and air) I am curious as to what the rwhp and torque is going to be...

Note that I am running wastegate actuator only. I removed my MBC because with the new actuator i was doing 1,2bar. With the can only I am running 1 bar exactly and spoolup is excellent: 1 bar @ 3500rpm with 50% TPS :)

Savington 04-06-2009 05:48 AM

12.0 is lean. 13.0 at 100kpa, 12.0 at 128kpa, 11.5 or richer above that. No exceptions. I am tuned to see low 11s at 11psi at redline.

Laur3ns 04-06-2009 12:53 PM

2 Attachment(s)
Good point, I've changed my target table to this and will retune:

Laur3ns 04-11-2009 03:23 PM

Refabbed the air inlet plumming (new filter, MAF removed, cleanup). Then I notice the vacuum hose from the OEM FPR to the solenoid thing near the TB is lose. Reconnected and zip tied.... then Im lean <100kpa and rich above. Sounds plausible?

Spend the entire evening retuning and Im done now.

Toddcod 04-12-2009 08:42 AM


Originally Posted by hustler (Post 389899)
why is your shit lean? Because Jesus cries when you look at men and touch yourself.

That isn't funny, and crude. Anyway.......

When you comming to town? I haven't seen the beast yet.


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