17 replies to this topic

[kr0nic]

Hi Guys Have just been told when i went to get my car tuned that the dump pipe off the primary turbo (VF32 ? ) had been made to big and was overspooling for the last 5 months doing damage to my primary turbo! fork! What do you guys advise me to do ? I guess ill be looking at buying a replacement VF32 as there isnt any other turbo thats better then this one is there ? And to fix this dump pipe issue should i get MRT dump pipes ? The guy who told me my current dumps were no good works for MRT and wouldnt tell me what size the dump should be..... Anyone know what price id be looking at to get a new dump from the primary put on ? I assume i could get JUST the dump from the primary and not have to get a new dump for the secondary as well ? (very little knowledge of dumps on my part here) If i was to get a new dump they should be able to put a flange on the end and attach it to the rest of my current exhaust system yes ? Im spewing so bad about this! I was expecting to get my car back as a new machine freshly tuned and instead i get back the same old car just knowinig the turbos forked!! GRRR !!!! VERY tempted to sell the B4 and buy a WRX grr

[XXB4XX]

Calm down champ, More thank likely, what they are telling you is here-say, as long as it still sounds good and boosts, don't worry. What size is the dump pipe? the maximum I recommend for the B4 is 2.5 inch off both the turbo's. Mine worked and still does work with that setup, no issues.

[cracka]

fark dude i just sold my modded turbo's. if yours really is stuffed i'll see if he wants to sell his stock one when he's ready to put mine on. #1 is the turbo actually stuffed #2 are your dumps custom , what size is the primary dump , have heard issues with 3", but only from MRT ? #3 a good exhaust shop could always change pipe size. my zorst from mrt simply unbolted from the primary, either way, doable.

[kr0nic]

Oh phew, well im a bit happier after hearing this, to ME the turbo sounds fine, theres a slight 'vibration' if you will when i back off from low rpm eg 2.5k but nothing major at all. Its got 2.5" dumps off both turbos, so you guys reckon its not that big of a deal ? I will get a quote to change the primary dump down to 2 1"4 . Id relly rather not get a new turbo....... Its a full custom system, 2.5" dumps into 3" thanks guys

[hawks_123]

Don't change your zorst just yet. Look around and get another primary turbo as spare. If that turbo goes then change it and think about changing the dumps. Used turbos are not really that expensive, probably as much as it would cost to get your zorst fixed.

[cracka]

now i'm confused, mrt sell 2.5' ptimary and 3' off the secondary

[kr0nic]

now i'm confused, mrt sell 2.5' ptimary and 3' off the secondary

Mmmm can anyone else confirm this ?

I got the car back just now, talked with Adam at RPM Automotive he is gonna get a guy he knows with a MRT turbo back exhaust to come in and measure his dumps. I am worried that if the turb goes i cud bugger the engine........ i know its a low chance that it will be the intake impeller that goes but with my luck lol.......

So ill take the car back down in a week or two if it is true that my primary dump needs to be smaller and get it replaced. THEN hopefully it will get on the fricken dyno!

[buzzda]

Mmmm can anyone else confirm this ?

I got the car back just now, talked with Adam at RPM Automotive he is gonna get a guy he knows with a MRT turbo back exhaust to come in and measure his dumps. I am worried that if the turb goes i cud bugger the engine........ i know its a low chance that it will be the intake impeller that goes but with my luck lol.......

So ill take the car back down in a week or two if it is true that my primary dump needs to be smaller and get it replaced. THEN hopefully it will get on the fricken dyno!

"cracka" had MRT dumps on his

wouldn't be too worried bout the turbo stuffin the engine if it goes as any bits still have to make it thr the IC.

[cracka]

might have something to do with the rest of your zorst and back pressure as i just sold my MRT dump pipes which had 2.5" primary and 3" secondary
one of the best dumps i ever come across but had to sell one of my kids to afford.

actually,,, thay look the fuggen same to me.

[XXB4XX]

3 on the secondary is ok-ish.. But I didn't risk it and went 2.5 on both..

[Billsy]

lol, overspool the turbo, hahahaha Bu**shit sounds like MRT trying to sell you their crap. how much boost are you running, if you say 18+psi on the primary then thats the issue, you cant over spin the turbo unless your pushing it too hard and like all things the harder you push the turbo the shorter its life will be, the dump size plays little part in the way these operate. the difference that makes a TT dump special is the flange, weather its got bell mouth, divorced wastegate or just a plain flat plate (like the above and what stock are like) ive pushed and pushed the stock turbos as far as they can possibly go and all ive had happen is the oil seal on the compressor side starts to leak into the cooler pipe under boost. the turbo may be worn but the dumps have nothing to do with it. its how its been treated, the oil its been fed and how its been driven.

[XXB4XX]

To all new members, When the man himself replies to your thread, you might as well close it. Billsy, Subaru and mrt would love to get there hands in you, prob not in a good way though!!

[twinturbosubaru]

Haha, yeh good reply Have to agree though, I ran 1.2 bar on my Gen2 for 6 years and never had issues, the dumps are simply going to let them flow better and whatever boost you are running is going to be the ONLY determining factor for lifespan. If the turbo goes, it's not going to blow up, it's going to wear out, seals will go, bearings will seize, but it won't blow up, not unless you have some rare catastrophic failure of some stupid magnitude, I concur with Billsy that somebody is trying to sell you turbos, sure it may be worn, but seat of pants and boost gauge will tell you if it is buggered or not. BTW, 2.5 and 2.5 for the dumps is good, actually 2" and 2.5" on secondary is better for back pressure and overall result on a engine with minor mods, you can't flow more air than that which comes through from a 2.5"/2.5" setup from a B4 engine anyway so by increasing pipe sizes more only reduces back flow unless you restrict it back further, and if you are going to do that why have big dumps ! Regards Paul

[XXB4XX]

Yep Paul, spot on too.. I went the 2.5 - 2.5 even though people were telling me to go 3.0 on the secondary, but it would also be pointless due to the sheer tiny-ness of the turbos.. if the B4 had a Garrett T76 as a secondary, then a 3inch dump would make sense.

[tinhow]

Mrt told me the same thing that changing the primary dump will cause overspoolin. Whenever you pull down your primary I would recommend increasing the hole in the banjo bolt a little more. This will aid in more oil reachin the turbo hence better coolin. I did this to my primary as well as porting the turbine entry. Another mod you can do is put a TD04 on the secondary, this setup should work better with the 2.5 dumps.

[kr0nic]

Appreciate the the help fellas, especially Billsy & Paul! & Cracka for that pic I will be getting the dump pipes taken off next week and the primary turbo 'felt' for damage (do much hassle taking it out completly....) If it seems ok i will discuss options with my mechanic about what can be done to reduce this so called 'overboost' Its pretty annoying that MRT pretty much refused to tune the car because of this 'issue' ..... One other question , iv noticed the car will sometimes boost up to 17 or so PSI when the second turbo is in full flight but other times it will only go to 12-13 ... Is this likely to be a ECU issue ? When MRT test drove the car they said it was quite a bit quicker then any other B4 without a tune they had ever driven... could this be because for some reason my car is boosting up to quite high PSI levels sometimes ? eg 18 PSI flat chat in 2nd or 3rd gear ? Thanks Guys!

[ams]

Mine only makes 11-12 with no tune.

[twinturbosubaru]

Is that high boost sustained or just a spike ?? Bigger dumps and less back pressure will see higher spikes in your boost, but your boost controller should bring it back down to respectable levels in a reasonable period of time, a second or 2. Another issue with B4's is that because the secondary has no wastegate if you are running really high boost and the wastegate on the primary can't flow enough gas to get rid of it then you can get overboosting, porting the wastegate on the primary can address this. The only real way to stop overspinning, which is not an issue unless you run a reasonable amount more boost than stock, is you can get hybrid turbos which address the issue, to be honest I'm not 100% sure about the B4, but I know on the Gen2 Legacy you can fit the compressor core and housing from a secondary onto the exhaust housing of the original primary which means you get the same response as before but get better boost without wringing the nuts off the turbo to get it. MTQ do a conversion for this, so maybe worth a call to them to ask, they have offices in each state from memory. It has to be done professionally though as the housing needs to be machined. This could be a viable option which will give you the performance you want without the longevity issues as long as you keep it sensible. For what it's worth I wouldn't send my worst enemy to mrt, I've heard too many bad stories about them and ecu tunes. Regards Paul