35R Surge / HWY Gears

[Mike1992]

2 years ago I purchased a new FP HTA GT3582R with a T3 .63 a/r housing and am having some issues with surging at full boost in 4th and 5th gear on my 95 2.0l I'm currently running about 22-24psi. The compressor housing inlet on my turbo doesn't look exactly like the one on their website either. The interior snout is shorter thrn the picture shown. What can I do in attempt to fix this surge issue? I have no issues 1st - 3rd gear anytime but only on the highway attempting to boost in 4th and 5th and not until full boost. This isn't a terribly huge issue just annyoying when I'm trying to pass someone quickly on the hwy.

Modlist
1995 TSI AWD -Ross/Eagle 6-bolt, Ported 1g Head, BC S&R, FP2 Cams, SS Valves, Mitsu MLS/ARP L19's, Fluidampr, Forrester Intake Manifold, 70mm TB, FP Intake/K&N, GM 3Bar, MAF-T 3" GM Maf, 50mm BOV, Turbonetics manifold, Tial 38mm, FP HTA GT3582R, 3" TBE, 1000cc Injectors, Walbro 255, Aeromotive Regulator, ECMLink V3, Innovate MTX-L Wideband , Dynatek ARC-2, VRSF FMIC, Prothane Mounts, Shep Trans, Evo 8 Rear Diff, Megan Coilovers etc...

 

[LandSpeed-DSM]

Bigger turbine housing. As a bonus you will make more power at the same boost level as well as extend your rev range. I wouldn't run a 35r turbine with the 82 and 86 compressors in the little .63 T3 anyway.

 

[Mike1992]

I assumed switching to a larger a/r turbine housing would help, however the increased lag may not be worth it for a dd.

 

[LandSpeed-DSM]

I think you'd be surprised. You may not feel a punch like the small housing, and it may take a few hundred rpm to hit the same boost.. But you will be faster. Its not like you're putting a larger wheel in.

If your making more power post pound of boost, the advantages will more than outweigh a perceived lag penalty.

 

[Mike1992]

Whhat kind of increase in lag would I be looking at? I currently hit 22-24 psi around 4200-4400rpm's in 3rd.

 

[LandSpeed-DSM]

Next step up is the .82 T3? If it was more than a few hundred rpm in third I would be surprised. You will make the same power at less boost.. meaning more than likely at the same power at 4300rpm in third at less boost, and more power at the same boost, just a bit later. It will be faster in spite of some lag.

 

[94awdcoupe]

are running a 4 inch inlet? you shouldnt be getting surge. I have a 63 on same turbo with not even a hint of surge. tyipcally see 30 psi at 4600 but have seen 30 psi at 4100rpm 3rd gear. had standard 35r with no surge cover on same setup. and it was undrivable from 2500rpm. surge was horrible. bought precision bullet hole cover to solve problem. but it did nothing to stop surge. then I upgraded turbo to fp to get correct cover.

 

[black_gst]

compressor surge is your turbo calling you a #### for not running enough boost , turn up the boost and you wont have compressor surge

 

[eclipsegsx1736]

2 years ago I purchased a new FP HTA GT3582R with a T3 .63 a/r housing and am having some issues with surging at full boost in 4th and 5th gear on my 95 2.0l I'm currently running about 22-24psi. The compressor housing inlet on my turbo doesn't look exactly like the one on their website either. The interior snout is shorter thrn the picture shown. What can I do in attempt to fix this surge issue? I have no issues 1st - 3rd gear anytime but only on the highway attempting to boost in 4th and 5th and not until full boost. This isn't a terribly huge issue just annyoying when I'm trying to pass someone quickly on the hwy.

Modlist
1995 TSI AWD -Ross/Eagle 6-bolt, Ported 1g Head, BC S&R, FP2 Cams, SS Valves, Mitsu MLS/ARP L19's, Fluidampr, Forrester Intake Manifold, 70mm TB, FP Intake/K&N, GM 3Bar, MAF-T 3" GM Maf, 50mm BOV, Turbonetics manifold, Tial 38mm, FP HTA GT3582R, 3" TBE, 1000cc Injectors, Walbro 255, Aeromotive Regulator, ECMLink V3, Innovate MTX-L Wideband , Dynatek ARC-2, VRSF FMIC, Prothane Mounts, Shep Trans, Evo 8 Rear Diff, Megan Coilovers etc...

How are you controlling boost? It's a bit of a bandaid, but you can do RPM based boost control in higher gears with V3 to prevent surge. I had this same problem tuning a 2.3 Galant VR4 but it was a DSM HTA3582R with the bolt-on housing, so I'd almost expect it since the turbine housing is quite small for such a high power potential turbo.

compressor surge is your turbo calling you a #### for not running enough boost , turn up the boost and you wont have compressor surge

Higher boost at the same RPM (airflow) will only make the problem worse:

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[donniekak]

compressor surge is your turbo calling you a #### for not running enough boost , turn up the boost and you wont have compressor surge

That's not the issue. Please read up on how turbocharger compressors work. It's surging from having to high pressure ratio (boost) and not enough flow. This is operating the compressor to the left of the surge line on the map.

This is usually caused by to small of a turbine, or turbine housing. If the turbo spools to soon the engine won't flow enough air to keep the turbo to the right of the surge line.

 

[eclipsegsx1736]

That's not the issue. Please read up on how turbocharger compressors work. It's surging from having to high pressure ratio (boost) and not enough flow. This is operating the compressor to the left of the surge line on the map.

This is usually caused by to small of a turbine, or turbine housing. If the turbo spools to soon the engine won't flow enough air to keep the turbo to the right of the surge line.

Yup! Exactly.

As a side note to the OP, I used to have this with my old 2.3L/GT3076R bolt-on housing setup when running over 25 psi in 5th gear low RPM. Interestingly enough, it suddenly got way worse one night, and I eventually discovered a rather massive boost leak (ripped coupler). When I replaced the coupler, it went away (or at least back to how it was). Thinking about it, it's odd that this would increase compressor surge effect, as I'd think having a boost leak would effectively increase the airflow exiting the turbo. Nevertheless, it's worth mentioning.

 

[Mike1992]

I'm running V3 lite with an old Maf-t setup and run wastegate pressure 22-24 psi off a Tial 38mm thats manifold mounted. 4" intake pipe that runs in where the stock sidemount is located. I should have the ability to run more boost on my injectors if need be. I'll also run a BLT very soon. Thanks for the suggestions

 

[Archer Fabrications]

Your not afraid of blowing shit up with a 5th gear pull on a 35r? Your a brave man.

Thats alllootttt of engine load.

 

[LandSpeed-DSM]

I'm running V3 lite with an old Maf-t setup and run wastegate pressure 22-24 psi off a Tial 38mm thats manifold mounted. 4" intake pipe that runs in where the stock sidemount is located. I should have the ability to run more boost on my injectors if need be. I'll also run a BLT very soon. Thanks for the suggestions

Again.. more boost will make it worse.

More effective surge porting on the compressor cover would help, but that is a band-aid fix.

The real solution is a larger turbine housing

Or increasing your engine's demand flow (VE) in the region you are running into surge and shift your engine demand to the right of the surge line in reference to the compressor map..

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Those demand lines are not for a 2.0L, but its the same idea. more boost will push you further off the map.


Whether that is done through a different intake manifold or adjusting cam timing.

 

[Michael@FP]

I think I responded to this already in e-mail but first off all you need to confirm that what you're experiencing is actually surge. Most people have never really experienced compressor surge especially on 4G63's and usually they are misdiagnosed.

Compressor surge feels like boost/fuel cut and the car will momentarily drop power and it a real severe case can actually cause the car to buck violently. It's also rare in a turbo this size to see surge at WOT in any gear unless you're hitting it flat open at <2000RPM which in that case, use another gear. If you're hearing a "chopping" or "fluttering" sound that is not compressor surge and you likely have an issue with your boost controller, bov, or wastegate.

In the off chance it is actually surge, then Landspeed is correct the right answer is to increase the size of your turbine housing. It's either that or increase the efficiency of the motor in the RPM range that you're seeing the surge, unless of course you're trying to make it surge, then well stop doing that.

-Michael

 

[Michael@FP]

compressor surge is your turbo calling you a #### for not running enough boost , turn up the boost and you wont have compressor surge

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I hope

 

[Mike1992]

Thanks for the reply. I don't know what to call it, I'd say the sound is coming from my BOV. Its like a chopping noise as you had sad. Its an old style Tial 50mm with a fairly soft spring. Maybe I need to put a stiffer spring in it? Wastegate is a Tial 38mm with 2 springs inside to acheive my boost level without a boost controller.