Trying to Solve Fuel cut - at wits end - this one will stump you

[Boost Lee]

Hello Y.O. supra89T.
The problem here doesn't appear to be the AFM, rather a minor design flaw of this turbo.

Converting to external wastegate just may do the trick.

Guess we'll find out Tuesday.

Jeff

 

[ArmandoP]

get yourself a hks vpc and get rid of that afm PROBLEM SOLVED

hmmm, so youre suggesting I have an electronics problem even though the car boosts when the wastegate is wide open? That makes so much sense, Im surprised I hadnt thought of it. :nono: :/sarcasm:

I appreciate the help people, but please attempt to understand the problem before making suggestions. We are past the point where the electronics are a problem.


Hommer, The problem seems to be stemming from the fact that I cant get enough exhaust through the wastegate port bypassing the turbo even though its already been ported. I can tell this because it still boosts up top even with the wastegate wide open, I also know that the wastegate is opening up at 5psi when it is hooked up, yet Im still slamming into fuel cut at 14psi without any additional boost control devices.

For those who keep suggesting we get around it by getting rid of the AFM and its limitations, what do you suggest when the boost keeps climbing and Im having the same problem at 20psi? Fuelcut is the only reason my engine hasnt shat itself. Im not regulating boost to 14, thats just where fuelcut kicks in, god only knows how high the boost would climb if I got rid of fuelcut or the AFMs limitations withoutfixing the underlying problem. ALWAYS FIX THE UNDERLYNG PROBLEM BEFORE MASKING THE SYMPTOMS. RULE OF THUMB WHEN MODIFING.

Here are the options as I see them...
1. reroute the wg to recirc into the DP just in case my problem is with scavenging.
2. convert to external gate
if the problem persists then I have no idea what to do next, maybe a LARGER external wastegate?.
3. get rid of the turbonetics turbo and convert to a lipp boss series which appears to have a larger wastegate port.
4. get ahold of a lipp turbine housing and make it work with the turbonetics turbo.
5. give up on this setup and do what I should havedone from the beggining... GT40R custom mani, custom dp, big ass intercooler, FFIM and an AEM ECU.
6. swap in a 2j (cause when all else fails just get rid of the whole damn thing. hehehe)

I am open to suggestions and appreciate others' expertise, hence why I posted here, but they need to help solve the underlying boost regulation problem. Right now I have no desire to remove fuelcut as it solves nothing. Ask me again once the wastegate issue is resolved and Ill be first in line to crank that shit up and start tuning. MO POWA!

believe it or not, all of the performance parts I have installed have been a result of upgrades due to the stuff the PO screwed up before I bought the car. (intercooler pipes, headgasket, studs, downpipe, turbo is all just me trying to get this damn thing to run right before I really start modding it.) I guess this is what I get for trying to do things right.

John is as stumped as I am. Ive consulted with friends in the alltrac and MR2 world as well, and everything points to the big turbo and ddp combo. At this point Im convinced its not an electronics problem and that Im not outflowing the AFM. After all, when the wastegate is wide open from idle, I should not be boosting at all. (I found this out when I built my first turbo MKI Mr2)

Those of you have took the time to consider the problem and offered suggestions I really appreciate it. You kept me from throwing a bunch of napalm in the engine bay and tossing the car in the river. Im very grateful, the next meet I see you guys, please let me know who you are and you got atleast a couple beers on me! Im not done with this problem, just saying thanks by the way, cause I STILL want to napalm this damn car and go back to MR2s. hehehe That may change after I finally see what this chassis can do.

 

[chevyeater]

Do you have a stock turbo elbow laying around? Or anything besides the BIC DDP?

 

[ArmandoP]

Do you have a stock turbo elbow laying around? Or anything besides the BIC DDP?

Thats a damn good idea. I dont have one, but I some people who may.... Ill see if I can borrow one.

 

[Doward]

I can't possibly see the stock turbo elbow outflowing.. well, anything at all. LOL

Armando, the reason I recommend tuning, is that running 550s (or are you running 580s? no matter) you can use the maft-pro to tune some of that rich condition out - which will reduce the frequency to the TCCS, and prevent you from hitting fuel cut.

Smaller wastegates are generally able to control higher levels of boost easier, because you need less bleedoff of the exhaust to hold a higher boost level.

That said, I'd wager the external wastegate will fix your problem completely

 

[ArmandoP]

I can't possibly see the stock turbo elbow outflowing.. well, anything at all. LOL

true, but it would help eliminate the divorced downpipe as contributing to the problem... a small benefit for minimal effort.

Armando, the reason I recommend tuning, is that running 550s (or are you running 580s? no matter) you can use the maft-pro to tune some of that rich condition out - which will reduce the frequency to the TCCS, and prevent you from hitting fuel cut.

580's according to the markings. I had not considered this. makes sense. Would make a strong case for why I should have installed a maft pro when I first looked at them 8 months ago or so. still, fromt he feel of it, Im convinced that if I raised fuelcut, this thing wouldnt stop building boost till redline, and who knows how high it would go by then. :/

Smaller wastegates are generally able to control higher levels of boost easier, because you need less bleedoff of the exhaust to hold a higher boost level.

I would say that properly sized wastegates etc... no? a horribly undersized wastegate would lead to overboosting problems that worsen as RPM increase, right? just my understanding of what is a complicated issue. I could be wrong, its been known to happen from time to time.

That said, I'd wager the external wastegate will fix your problem completely

I agree. and if that dont work, John says theres a plan B which hes being pretty quiet about. LOL

 

[Doward]

Which, knowing him, will rock your world You may want Plan B anyway

Just to ensure you understand correctly - if you were currently running 10:1 AFR, hitting FC @ 14psi, tuning back to say 11.5:1 AFR would most likely push your FC up to around 16-17psi. Tuning will not eliminate your FC (unless you clamp the output frequency which UNDER NO CIRCUMSTANCES WOULD I RECOMMEND) - only raise it up.

My thought was simply would it raise it above the level you are currently building boost to?

Either way, you're in good hands with MDC

 

[Facime]

I agree. and if that dont work, John says theres a plan B which hes being pretty quiet about. LOL

Heh, I wonder what that could be

The tuning propoistion is the same thing I suggested a few pages back. But I think it going to turn out to be a good thing you didnt just give up and go that route. It seems you have a "hardware" problem, and you never solve a hardware problem with "software".

Any chance you could post up some pictures of aformentioned wastegate? I would like to see this housing in question.

 

[ArmandoP]

My thought was simply would it raise it above the level you are currently building boost to?

Either way, you're in good hands with MDC

well, If Im reading the comp map right, which is a big if.... infiniboost would be damn close to 30psi... bad. fun, but only for a split second Im sure. LOL

Yeah, Im thinking I may intentionally sabotage the wastegate idea... he mentioned something about P trim. That makes Mando happy.

 

[ArmandoP]

Heh, I wonder what that could be

The tuning propoistion is the same thing I suggested a few pages back. But I think it going to turn out to be a good thing you didnt just give up and go that route. It seems you have a "hardware" problem, and you never solve a hardware problem with "software".

Any chance you could post up some pictures of aformentioned wastegate? I would like to see this housing in question.

Ill take some decent pics on tuesday. My cameraphone sucks.
oh, and agreed 100%.

 

[Doward]

I'd have a hard time calling it a hardware problem. If the wastegate couldn't control boost below 18psi, for instance, I wouldn't call that a hardware 'problem' - just poorly matched hardware to the end user's needs. Just semantics here, lol

Any chance of leaking what Jon's got up his sleeve?

 

[ArmandoP]

I'd have a hard time calling it a hardware problem. If the wastegate couldn't control boost below 18psi, for instance, I wouldn't call that a hardware 'problem' - just poorly matched hardware to the end user's needs. Just semantics here, lol

Any chance of leaking what Jon's got up his sleeve?

no leaks coming from me...

let me ask you this. How likely is it that this thing WILL control boost starting at 18psi or so? If I could run 15-20psi and tune it properly Id be happy. My concern is that it will not stop building boost at 18psi. I think this because it slams into 14psi. Im starting to see your point about a smaller wastegate now.

 

[Doward]

The way I see it, you're at a point where you WILL benefit from fuel management.

Going the MAFT-pro route will allow you to simply check that. Honestly though, if you've got Jon nearby, you'd be CRAZY not to let him take a look at it! I was only throwing that out as a suggestion.

Personally, I'd have Jon go over it all first, and correlate with him regarding what you should do.

 

[Adjuster]

My experience with the bolt on T4 based turbo from ITS, with the Turbonetics sourced hot side housing was mixed.

ON the stock 7MGTE it worked rather well. Raised the point where the exhaust flow was choaked off above the stock RPM range, so no more flat power over about 5500rpm..

I ported the crap out of the hot side housing. Both on the manifold side, and the down pipe side.. Also opened up the wastegate hole, and smoothed the radious for that hole as well.

On 550's, and the Lexus airflow meter with a drop in K&N and modified air box, it made 420rwhp at 18psi, and rarely hit fuel cut, but was not very responsive to running more boost anyway.. (I tried both a manual pressure regulator based control, and the E-01 from Greddy, and neither really ever did a good job of allowing me to raise the boost..)

In the end, simply shimming the gate, or adjusting the rod tension turned out to be the best options for the stock CT, and later the bolt on T4.

When I built the stroker 3.24L motor, the bolt on T4 acted like a stock CT with very fast spool, and wicked FC, especially when it was cold. (Too much Hz rate increase at too low RPM from what I can figure/read/learn about this from guys like JetJock and Doward.) Also it would FC if I floored it in say 4th or 5th gear at 70mph.. Instant fuel cut when the turbo spooled up instantly at that speed.. Again, rpm is about 3500 in 5th at 70, or slightly less, and the spool on this smaller turbo was very quick. (It had a dual ball bearing CHRA, and you could blow on the compressor, and make it spin easy... there was so little drag..)

I determined the following if you want to stay on the stock TCCS/ECU and run a well designed/adapted piggy back. (The Eman is not your best choice, I've been there, and done that, and it's OK, but not stellar.) The Maft Pro is the best thing next to a full stand alone, and from what I've read/researched, it can handle what I need it to do. (At least, that's the plan.)

My theory is to run larger injectors, and turn down the Hz signal to compensate.. Raising the FC level, but then use the Maft Pro to monitor, and adjust the timing changes as well...

I also changed to a higher flowing turbo and manifold with external waste gate that should handle everything I'd need for awhile power wise.

The 780cc injectors should lower the Hz rate so it will not FC at lower RPM when the turbo spools up and pushes boost, and the turbo this time around is a simple Master Power T-70 with the 69.5mm compressor wheel, P-trim exducer and .63 AR hot side housing... (Ported of course for more flow, but it should still spool up quite fast.. Especially with a 9:1 3.24L 7MGTE blowing through it.)

If this Maft Pro/TCCS setup does not work, and I can't tune out the FC, then I'm either going to sell the car, part it out and sell everything off, or bite the bullet, and get a stand alone from Motec or some other option for complete control of the engine/fuel/ignition situation.

In the meantime, I'm having too much fun riding the FZ1 to bother with it at all.

 

[GrimJack]

Before doing anything bloody big and expensive, I'd try these:
- Port the wastegate hole in the DDP a bunch
- Switch to a DP with a single big opening, instead of a separate wastegate pipe.

I'm thinking that the turbo backsection has already been ported enough to flow the gas needed to avoid boost spike... but the DDP has not. Both of mine are heavily ported.

If this doesn't solve it, I'd say that the 62-1 flows so much more than the 60-1 that you just cannot avoid boost spikes with the DDP.

 

[Quin]

From what I understand the whole shebang has already been ported. I'm gonna let him borrow my non-DDP and see if that takes care of it.

 

[ArmandoP]

Heres a tip off as to plan B...

ATP-STL-009 (SS) Steel Straight Pipe - 4.00" - 2 foot section 1
ATP-STL-021 (SS) Stainless Steel 90 Degree Elbow - 4.00" OD 3
CLC-CLA-014 V-Band Clamp - 4.00" 2
ATP-FLS-086 V-Band and 4" Machined Flange and clamp Set 1
ATP-FLS-004 Steel - External Wastegate Drilled Flange 2
TBN-GSK-001 External Wastegate Gasket 1
ATP-STL-027 Stainless Steel 1.5" Diameter 45 Degree 1
Shipping: UPS Next Day Air Saver:

apparently john has the rest fo the stuff to make the mystery plan work. hehehe.

 

[MDCmotorsports]

If mystery plan B goes ahead, Armando will be able to pop 450hp easy.

Hopefully not pop rods. :-(

 

[ArmandoP]

If mystery plan B goes ahead, Armando will be able to pop 450hp easy.

Hopefully not pop rods. :-(

Theres a reason Ive been running with no boost controller.

 

[jonstew]

Theres a reason Ive been running with no boost controller.

This coming from a man who told me "they're always fastest just before they die!" wth a long and storied history of blown motors to prove it. If you get that car running right I give it 2 months before you are trying to convince AAA you are me so you can get the car towed for free. :biglaugh: