wang4u

iTrader: (3)

The car is a Evo 5 conversion with Evo 5 motor swap. FP Black, tuned. PTE1200cc and Wally 400lph. Tial bov on SD. E85.

The fluttering/bucking is happening between 3800-4200rpm in any gear, partial throttle. Occasionally it will be happen from 1st-3rd at full throttle. It has always happened in 4th and 5th gear. Heres the odd part... beyond 4200ish rpm, it pulls very hard, all the way to redline, any gear. When the flutter/buck is happening, afrs are all over the place. Predominately more rich than lean.

I had a couple ideas and a few new ones. First the Tial was sharing a vacuum source with the MAP sensor (Evo 7 intake manifold doesnt have provisions for MAP). That has since been changed to single source for each, and running 1/4" braided hose to each.

Second, building a COP system and tightening the gap. Currently running .022 with BPR7ES plugs. the IX plugs made no difference. The COP made no difference either, maybe a smoother idle.

Third, nothing wrong in the tune. She drives well under 3800, and above 4200. We have played with the closed/open loop crossover points as well as WGDC. Neither has worked. If driven hard from the start, I dont experience any flutter/bucking as the rpms are always above 5k after each shift.

Fourth, the Tial came supplied with a 11lb spring. I inspected it very well and didnt notice any tears/holes in the diaphragm. I ordered a 8lb spring with no luck. If anything it was a little worse. Leads me to believe maybe I need an even stronger spring? The valve seems to operate lovely and is quick to respond while under boost beyond 4200rpm.

Lastly, the fuel pump isnt hardwired yet. We ran out of fuel above 500whp, but have since brought it back down to a reasonable IDC. I dont understand how this could affect a small portion of the rev range, esp when over 4200 there is no fuel issues.

One thing I need to try is swap ECUs. Maybe the problem is stemming from the ecu hence the other mechanical stuff has had no effect.

Anyone have any insight?

AdamAndEvo

My vote is the bov. Its got to be opening to soon. Mine does it also. Partial throttle, high load. Like say im cruising at 40 in 4th up a hill ( i dont do this. But for example sake.) if i let off the gas to light it flutters and stutters bad. But if i drop a gear and get it. It blows off fine. I put on a turbo xs rfl ( sounds terrible). But it was free. And allows you to stack washers under the soring untill it holds right where u want. Is there room in the teal?

wang4u

iTrader: (3)

It doesnt happen when I left off, it happens while holding partial throttle, high load. And likewise, if on the gas above 4200 it holds just fine. According to Tial and tons others, the spring only is for the vacuum at idle. So off their chart, Im seeing around -9 to -10hg of vacuum. Their chart says to use the 8lb spring, but that spring is clearly too light. I believe its possible to stack some washers inside. I will have to give it a try. In the future might just buy an adjustable bov to avoid this problem. Funny thing is on my old DSM, I had a Tial with 10lb spring. Zero issues. It had a bigger turbo and made much more hp.

slowsrt4:(

iTrader: (13)

change the spring in your bov to the correct spring, you match the spring based off of where your car is at in vaccum at idle

wang4u

iTrader: (3)

Its not the spring.

Aby@MIL.SPEC

iTrader: (161)

so if you do a 3rd gear pull @ wot, you will generate a boost plot vs rpm & based on what you say during a hard pull, all is good. ok

can you log the boost level / trace when this fluttering occurs?

i have a 2.4L on a hta grn, for me & my set-up, i can generate boost flutter between 2600-2800 rpm, this flutter is @ ~18-20 psi, in my 3-5th gear, slowly rolling on the gas when on the fwy.....

during a 3rd gear pull, iirc, i make ~9-14 psi during a pull 2600-2800 rpm

so i called that 3rd gear pull my boost limit & my wgdc is minimal above that boost level for that given rpm = no flutter during low rpm / low throttle when fwy merging, etc....

i hope that tuning method can help you.... if i want more power, i give it more throttle!

what w/g actuator are you running?

How many turns of preload do you have on the w/g actuator?

wang4u

iTrader: (3)

Yes Aby, in general, when WOT from say 2500 to redline, in 1st through 3rd, it pulls just fine. No flutter. Its when in 4th/5th or partial throttle in any gear does it flutter. Flutter only happens around 3800 to 4200rpm. No other rpm. Regardless of throttle input.

I havent had a great deal of time to log the issue. I need to this coming week for my tuner as well. I will post the log so you can take a look as well. From what my gauge says (not MAP boost) it happens between 19-22 psi. I will pass this info along to my tuner.

I ordered the Black with FP's 25psi actuator. I did not further preload the wastegate as I assume FP has already done that. One thing to note is when I first got the car, it had a Evo 8 turbo on it. It did exactly the same thing as its doing now. A year ago I thought it was the tune. Clearly thats not the case (or doesnt seem like it).

The likely culprit still remains to be the bov. My thought is that since Im running a Evo 7 intake manifold, maybe the manifold barb (on the front of the IM) is too small/clogged to quickly control the bov. Weird is that once at full boost beyond 4200ish rpm, it pulls very hard without any hiccups. That would suggest no boost leaks (and none that we could find), no leaks through the intercooler, and bov is holding boost just fine. We also checked the turbo. There is zero shaft play and it spins like butter.

Im still scratching my head on what this might be. A log should help pinpoint the issue further. I will get on that this week. Thanks for your input Aby

Samir Feroze

I am experiencing this exact same issue. After a gear change and as I get back on the throttle (partial or WOT), I hear a flutter (wrrrhhhhh, pulsating) and boost stops building. Then as the rpm climbs, it pulls strongly all the way to redline. Did you ever solve this issue?

2006EvoIXer

iTrader: (1)

Do you have the anti-surge cover?

http://www.forcedperformance.net/mer...e=Lancer-Turbo

If it's bucking, it sounds like your turbo is cavitating.

samir8

No, I do not. I appreciate the link to the product, but how would I know which one would fit my turbo (if it would fit at all). The turbo I have is made by JP Turbo and is sized between an FP Red and FP Black.

2006EvoIXer

iTrader: (1)

Contact JP and FP to see if they have anything that will fit. I'm not familiar with JP. I bought FP HTA71 for $700 and it came with their anti-surge. Call them both and find out all your options. GL

hokiruu

iTrader: (19)

Reviving this thread. Would any of you recommend the QR or QRJ for a 71HTA on E85?
My IX DV leaked at 30psi on the VIII 9.8, not I am going 71HTA and lower boost, so hopefully It won't be an issue anymore, but I am prepared to use something besides the IX DV if necessary and have been considering the QR or QRJ.

Project_Broke

iTrader: (2)

Go Speed Density and run a Tial Q 50. Buttery smooth and holds all the boost.

The QR would most likely be just fine, same construction really.

hokiruu

iTrader: (19)

Thanks for the reply. I am partial to recirculated DVs in any case, I ended up ordering a QRJ. I have been interested in Speed Density for a long time but my past tuners were not particularly interested in adding it for my previous setups. Maybe now.

LetsGetThisDone

iTrader: (1)

Q and QR are the same valve. On just has a home attachment to recirc it.

The QRJ is going to not be every great on the 71hta.

You should always go speed density.