I bet someone has one laying around.. Hell, I might even have one.

Well, again , this is a subject of MUCH speculation. Some have found that 12 Degrees of split is a good conservative number but I have since dropped down to 8 degrees of split across the board. Many have dropped the split to about 8-10 degrees and found 50-75 HP. I figured since I have an AI system, I can afford to run a little less conservative.

I couldnt really tell you what the stock map does, I always just assumed it remained at 15 degrees, but I am probably wrong..

AS far as AFRs are concerned, I always feel the car go sluggish when i dip below 10:5. Thats a LOT of fuel!

 

yes I know! I just wanna be safe until my boost problem is fixed. I have never seen a car go from 8lbs of boost to 18lbs in 1000 rpms in 4th gear. It is scary.

I am pretty happy with my tune being a solid 12.1:1 at 1-3lbs and 11.5:1 at 3-9. It just seems that the stock fuel map curves so exponetially that it runs pig pig rich when you just add percentages to the map. I need to drop down the 15lbs range and linearize it.

but for now 0-9lbs is cool with me and then after that I dump inthe fuel to keep my motor alive, but i am not even driving it untill its fixed.

 

You're messing with a stand-alone and running into overboost problems???
Oh gawd...


-Ted

 

haha, the tune was 90% there in the summer months. And I am not "messing" I know what I am doing with tuning, its just my first rotary.

but yeah the combo of adjusting fuel and not having consistant boost makes for a......well....interesting time! ahha. Hey if it blows...who cares. 1k later I have a nice new motor. I have been wanting to street port it anyways.

 

I just read your post in the Haltech section...

If you're using the too-much-fuel trick to keep the boost from shooting up, and it's still going it...you might have a not-enough fuel problem???

Can you monitor fuel pressure to make sure you're not dropping fuel pressure?


-Ted

 

I do not have a fuel pressure gauge at the moment. I just ordered a new fuel filter and am looking for a new/used wastegate to install.

The secondaries are the gsl-e or whatever injectors the 680's but the AFR are in the low 10's at 16lbs and duty cycle is in the 75% range so I hope it isnt a fuel issue.

Maybe I will grab a cheapo FPR at the parts store to see whats up, but if I have good baseline/idle Fuel pressure, how do I know if it is dropping off when I am reving?

BTW I have a new Walboro pump as well.

 

If AFRs are safe, and the IDCs arent bad, then it hardly seems like a fuel starvation problem.

 

Typically, we jack up the right side bars just to combat any possibility of boost spiking.

If you're getting around 75% duty cycle, you're really awfully close to the fuel injector locking open.
85% is the consensus on safe duty cycle.
So, I bet the fuel injectors are just running out of headroom even though you're trying to keep the turbo from overboosting - this explains why you can't just jack the fuel up to keep the boost from overshooting...


-Ted

 

" ported wastegate" is quite a large generalization. Tell us exactly what you have done. Enlarging the hole alone is only 1/3 of the correct way to control boost. Runner path, door travel, etc play a larger role.

Just because you're wideband says X afr doesn't mean you're not running out of fuel. Food for thought; most widebands sample rate is between 50-70 times a second. Not fast enough to see every combustion event. The serious guys I know have 2-3 widebands per exhaust port. As said before what is your fuel pressure? Unfortuneatly most cheap system are very inaccurate, you'll need an accurate pressure transducer to pickup your exact fuel rail pressure. The racepak systems I'm used to working on, have quite a variance in fuel pressure( 30 + changes in under .9 seconds esp under high Gs; ie launch)

It also sounds like your wastegate bushing is worn out, quite typical. Its really only going to hurt your boosthresold. Quick fix is put a spring on it, one side to the arm, one connected to the wastegate actuator.

Quite common to overboost in colder climates. Intake air is more dense; equals more volume in combustion chamber. Inturn creates more load and combustion pressure; more exhaust energy to drive the turbine. Quite a problem when you have a seriously undersized turbine, turbine a/r and wastegate. You really need dual 38mms to control that turbo.

Hopefully this mindless booze enfilled rambling has helped, lol..
I'd like to add a lot more but im done for now....

 

I was under the impression a wastegate was a spring, diaphram, and a piston/actuator. I did not know there where bushings.

I want to go to a BNR stage 3 but all this boost creep is making me wanna go external wastegate instead.

I have ported wastegate opening and runner path. did not do the door thing. Mind you at 60-70 degrees the car was rock solid at 7lbs with this port job.

This is def a mechanical problem.

and ReTed...how could I max out the 680's on a a stock turbo?? I wish I would have just bought 720's but these seemed to do the trick for now. When I shoot for 375whp I am thinking of selling the 680's and going 720/1600.

 

You claim 680 secondaries?
That's only ~12% increase of fuel capacity.
If you're running on the rich side (which you are), maxing your fuel injectors is easily possible with the stock turbo.

The stock turbo maxes out the stock 4 x 550's at 12 - 14psi no problem.


-Ted

 

well my goal was 12-14 psi with 550/680 to be safe I will sell these when I go big turbo

then the 720/1600 should cover the t04 375 whp goal. While I am at it if I go external wastegate, what is a good turbo to hit 350-375 on 93 octane with good midrange/ decent spool. I dont feel like $ for ball bearing.

Where can I get a wastegate for now?

 

Correct me if I am wrong, but the innovate LC-1 can achieve a 500hz sample rate.

Where is everyone coming up with this dual 38 nonesense? My single 46 isnt having ANY problems compensating for the change in air density..

 

j-rat you ever find an old map from your stock turbo days??

I would love to look at your timing split and timing maps.

I want to do a 5 split at boost transition and raise it up to reach 12 split at 1 bar then after that follow the stock map. The stock map splits at 5 and then at 1 bar is around 15 split.