I have been doing some research online, mostly between the fatboy SZ55 and the Perrin gt30r setups. Most people's opinions seem to be biased towards the setup they own. However, this is the collective knowledge I have gathered through popular opinion: For the the same spool, a rotated setup will make more power up top. Anyone had experience running all these turbos at some time? Installing the rotated mount kits is much more of a pain than the stock mount kits. What makes this such a pain to install? Moving coolant lines? Its easier to go back to stock with a stock mount kit. This might be necessary if the turbo needs servicing for any reason. The longevity of the ball bearings in the GT turbos vs the thrust bearing in the Deadbolt turbos. Have any of you rotated people had problems with maintainence for your turbo? This is all that comes to mind right now. Please post up your opinions/experience on these and other matters that you feel should also be considered. I'll post more questions as they come up. Please post only if you have information relative to the knowledge being developed in this thread.
Don't forget about the T3/T04e(s) that vendors like Ultimate Racing sell. I **believe** they use the thrust bearing. I think they can even build you one with a better bearing if you so wanted. Also, you can switch out the hotside of the rotated turbo. Not gonna happen with a stock-mount w/o sending it off (retuning required for either turbo) Also, while reading that the Perrin kit may be a little difficult to install, I've read nothing bad about the UR kits. Sorry, seems like a lot of **think**'ing in this post. Please remove if needed.
good info ped... i edited my original post to make it applicable to general rotated mount vs the stock mount turbos... i dont want to be restricted by manufacturer with the rotated mounts...
Matt’s Theory on Rotated vs. Stock location turbos Here are a few things you have to consider about stock location vs. rotated. 1. Wastegate Style A. Internal Obviously with an internal gate you are limited to what size opening you can have. They tend to be harder to control and don’t work well on large turbos. Internal gates are no usually found on rotated kits because most people that are going rotated are also going to a large turbo that internal gates are not found on. B. External External gates are larger and easier to control than an internal gate. They are really you’re only option when approaching the 500whp range. 2. Exhaust Housings This could get very long I will Try and keep it simple, I will get more detailed when I explain my personal setup at the bottom. A. Stock mount With a stock mount turbo the exhaust housing tends to get squished so that it fits into place nicely on the back side of the motor. When you squish the exhaust housing you limit flow and you also limit which turbine wheels you can use in it. B. Rotated mount Rotated mounts allow you to use a standard turbo so now you are not limiting the size or shape of the exhaust housing, large twin scroll turbos are now an option that you would never have with a stock mount. 1. Garrett Garrett limits you to .63 and .82 exhaust housings 2. Precision Precision lets you use a .48, .63, and .82 3. Compressor Housings I will also go more in-depth with this subject when I get into my personal setup. A. Stock Mount Just like the exhaust housings these also suffer in the stock locations, the housing gets squished and you can’t fit the really good compressor wheels in there. If you are staying 20G and smaller then this isn’t a problem. B. Rotated Mount No problem fitting big housings, so in turn there is a problem fitting a big compressor wheel. 1. Garrett Garrett uses anti surge housings on their GT series turbos 2. Precision(aftermarket) Precision you can order the turbo with or without the anti surge housing. You can also order different size compressor covers. (More on this in my setup) 4. Turbo Size Again with a stock location turbo you are limited on size, with a rotated you are not. 5. Inlet Size This is another place where you are limited by the stock location, you can only fit an inlet under the manifold that is so big, with the rotated mount you can go as big as you like. Stock location turbos The good thing about a stock location turbo is that it fits in the stock location, which means minimal fabrication work and a bolt on installation. Honestly if you’re not going bigger than a 20g or a Green then I can’t think of any reason to go rotated. Stock location turbos have no problem getting to the 400-450hp mark. Rotated Mount I like the rotated mount because it opens up a lot of options you can do anything from a TD04 size turbo to a 4788. You have now opened up the inlet so that the turbo can breathe; it doesn’t have to work as hard to make the same power so it should last longer. My personal setup My setup consists of the Perrin Up and Down pipe and the Perrin inlet (about to change to a MSPT). The turbo itself is the trick part of the setup because no one else is currently running it that I know of. It is a Precision GT30R (3076) with a T04S cover (no anti surge) and a .48 hot side. I hit full boost at 3600 rpms and the car pulls strong all the way to redline. If you are building a street car or a road race\autocross car then I would highly recommend this setup. We should have it on the dyno this week to confirm the numbers but I suspect that it’s making very close to 400hp on pump gas and I can assure you that Scott was very conservative with the tune. The car has run 1 hours sessions at Roebling Road and CMP and has never even had the slightest hint of knock. I can’t even begin to explain how much fun it is to drive. Matt (If you have questions fire away) Oh one last thing the anti surge housings on the gt30r are a huge waste of time and you’re spool will suffer, mine has never surged even with the small hot side on it.
great writeup matt... thanks so basically what i gather is that if you are going with BIG power (500+ whp) then rotated is the way to go since you are not limiting the airflow with housings, wheels and inlets... this is clearly seen with the 35r clearly outperforming the 65 lb wheel offering from DB or FP... it is also pretty clear to me that when going with something with a 49lb wheel or smaller (20g, SZ49, Green) you do not require the additional flow that comes from a rotated setup... hence it justifies saving the extra money and sticking with a stock mount turbo but what about 55lb wheel turbos... i guess they fall in a grey area since they are bigger than 49 and smaller than 65... most of the research i have done says that a rotated 30r will outspool as well as out power an sz55... however some people have shown plots that don't agree with this... maybe its different cars/different dynos/different weather, etc. so the comparison may not be fair... personally, i dont see myself going bigger than an sz55 or a gt30r... why do u think a rotated 30r would be able to outspool and outpower an sz55? from my simple understanding of turbos, bigger wheels and housings = more power and more lag... so the improved spool should come from either (1) the bigger inlet or (2) dual ball bearing design... is my reasoning correct?
In the case of the SZ55 vs. GT30R the bigger housing of the GT30R should be more efficient thus giving you a cooler intake charge and allowing you're ecu to run more timing. I am willing to bet that my 30R setup will out power and out spool the SZ55 Setups that Scott has tuned. Maybe Scott will chime in on this one and he can post up some sz55 charts, Ill see if we can put mine on the dyno this week and get some actual numbers. This is the right setup for me, but my car gets beat on, at the road course a lot. The last two events Scott and I have both been signed up for the car has been out in back to back sessions on a pretty much constant basis, it has not even shown so much as a single knock event, I contribute this to a couple of things, first Scot's tune is awesome and the turbo setup could not be better for the track(personal opinion). The Ball Bearings and the Inlet help for sure any time you can make it easier for the turbo to breath, spin, or exhale then it should be more efficient. I'm glad you guys like the write up, I'm going to try and do more but I've been really busy lately. Matt
2 corrections. It's my understanding that ball bearing turbo's will outlast bushing turbo's. Also, a Garrett can run with a 1.06 hotside too. (Dan's setup) I went with the rotated because so many people with the 20g/green went rotated later on. Just skip that step to save $$$. BTW, the 30r spools much better now that it's fully broken in.
Very informative guys! Can anyone sort out the confusion about the longevity of the bearing styles?? Also Matt, what is a MSPT?? Im kinda curious about the performance differences between an external gate to atmosphere (Ultimate Racing style) and a recirculated external gate (Perrin style) ??
I figured so. There was a sick external gated 35r sti at the dealer today and the gate is just too loud for my tastes (though it does sound insane!). I would have to have it route back into the downpipe. It scared the crap outta my mom when it popped open, lol!
Would a twinscroll setup be a more economical setup to a rotated? Better spool.....assuming you had a GT30R sized turbo that was twinscroll it would flow better than the rotated mount correct? All you would need is a exhaust manifold and uppipe and new turbo right? I r teh n00b
First Ball Bearing turbos last longer Second MSPT is Metric Subaru Performance Tuning, they have an intake that relocates the Maf into the fender well. Third I dont know that there is a lot of diffrence in the two style you mentioned, we actually disconnected my waste gate from the downpipe while at the track this weekend and it didnt really have any effect on the tune. Matt
The same basic rules apply to twinscroll setups, (in relation to squished housings). You can get normal turbos in twinscroll as well as stock location turbos. I'm sure that you are going to see a lot of twinscroll style turbos coming ont the market this year.
Would I be somewhat correct in saying a twin scroll turbo is like having twin-sequential turbos combined into one turbo in that there is a small and a large section of the exhaust housing??? Just trying to see if I understand the concept.
Twin scroll tubos have two holes in the exhaust housing and they each feed a diffrent part of the wheel, one of them is generally feeds to a smaller hole that creates a higher velocity charge, hence spooling the turbo faster, or atleast thats my understanding. Matt
here's a plot javid posted on nasioc in this thread: http://forums.nasioc.com/forums/showthread.php?p=13658129 this plot overlays javid's sz60 plot (red) on a rotated gt30r plot (blue)... both running meth at 28psi... the gt30r barely outspools the sz60 and makes less power through most of the band... the sz55 should noticably outspool the sz60 due to the smaller wheel and hence make less top end... so it isnt clear to me how the same 30r would be able to outspool as well as overpower the sz55 i don't have details on the specific 30r used... also it would be nice to see these plots starting around 2k... dunno if thats possible on a dynojet though
At 28psi, wouldnt the 30r be somewhat outside of its efficiency range? While the sz60, being larger, is more efficient at higher boost levels?? Just a guess...
Looks like that 30 R is probally reaching full boost in the 4200-4400rpm range, where mine makes it in the 3600rpm range, its amazing what you can do with proper housing selection and some good avcs tuning. Once again I hope we can get the car on the dyno this week and get some numbers so we can stop guessing. Matt
Well, considering the cost differences between the sz60 setup and the gt30r, do you feel like difference is worthwhile?
considering that i have a lot of parts already (dp, up, super16g that can be upgraded to an sz55), the sz55 route will be significantly cheaper than the rotated 30r... for someone considering the sz60 for an otherwise stock car, i think it would be better to go with the rotated setup sz55 is deadbolt's largest offering that can use the stock inlet and doesn't require TGV deletes
the ones i've seen like on the vf37 have equal sized holes. on a normal exhaust header you have both the exhaust "pulses" combining at the uppipe into one stream. twin scroll connects both ends of the header directly to the inlet on the turbo. since each pulse directly hits the turbo wheel without getting turbulence from the other side, it spools up more efficiently and thus quicker(400-500rpm)
I belive the entry holes on the turbo are the same size but one necks down smaller than the other as it gets closer to the turbine, but I may be wrong. Matt
The differences are worthwhile to me, however its hard to say if they are worthwhile for most people. If you are already stage 2 then its probably hard to justify, if you aren't stage 2 then its really not that much more expensive, Ill do the break down for the rotated setup Turbo $1000-$1200 Uppipe and Down-pipe and Gaskets and oil lines $600 Waste-gate $400 Inlet Pipe $300 (this comes with an adapter for the intercooler piping) Fuel Injectors $400 Total $2900 Stock Setup SZ55 $2150 Uppipe $200 Down-pipe $300 Fuel Injectors $400 Inlet Pipe $300 TGV Deletes ? Total $3350+ possible tgv deletes Wow I had no idea that the SZ60 and Sz55 were that expensive, in that case there is no way I personally would go with a stock location setup. Matt
I would run the rotated turbo hands down. The SZ series turbos are great turbo's, but will not come close to the effiecency of a rotated turbo. Not only do the rotated turbos make more power but they can do it with less boost and less exhaust back pressure. Less exhaust back pressure means you can run more timing due to less unburnt gasses entering the combustion process. In the long run a rotated turbo is going to put less strain on the motor and offers more option for upgrading or changing the way the turbo spools... not something you can do with a stock location turbo. As far as I see it there is no cost advantage of runing a stock location turbo now that Ultimate Racing has their T3/T04e turbo kit. We sell that rotated kit for $2450. It comes with an intake, uppipe, wastegate, downpipe, turbo, oil lines, big maf, etc... for the price you cannot beat it. Hell to buy a stock location downpipe, inlet hose, intake, and a turbo... would cost around 2800
Not really.... the only thing is you need to let the GT turbos idle for a bit longer since they take forever to slow down. Not sure if you have ever watched a GT turbo, but after you shut off the car they will sometimes spin for two minutes before stopping. I would say if you treat it right there are no issues... but that goes for any turbo.
Something else about the twin-scroll setup is that it's supposed to be "better" because it maximizes the exhaust pulses from each cylinder, rather than blending them all 4 together it splits the 4 into 2. Not sure how this helps seeing as most Suby's have unequal length ex. manifolds anyway, but it's something I remember reading in a turbo book somewhere.
about the completeness of the perrin kits: i see they come with stainless steel up pipe and down pipe, Tial 44 wastegate, a complete intake system, oil and water lines, and the desired turbo... the pictures look like they have a recirc hose so the stock BPV should work for pump gas applications (<22psi)... so for an otherwise stock car, if one were to buy the perrin kit, then the only additional components needed would be FMIC, injectors and EM (maybe AVC-R)? am i missing something? are any other expensive parts/services needed to get the setup running right?
You can actually order the perrin kit two ways, you can order it complete(all of it even the turbo) or you can order the setup kit with consist of the upipe, downpipe, all the lines and the gaskets. Then you can also order the intake separate. Scott says he just saw the ultimate racing kit and it is also very nice. This is what I would order Perrin Setup kit ( upipe, downpipe, oil lines, and gaskets) MSPT Intake kit (relocate filter and maf into fender well, I believe this comes with the maf housing made in, so no need for a big maf) Precision Turbo (This is where it gets tricky) (I run a GT30R(3076) with a TO4S cover and a .48 back side) I would say this is the minimum required to get you to 400hp on pump Modified injectors 740-800cc Tial 44mm waste gate(make sure that you put double lock nuts on this when you put it on, they will vibrate loose if you don't. Cobb Access Port, 5 different maps, no need for a boost controller, you just switch maps if you want more boost. That's pretty much it. If the car came with this setup from the factory no one would ever complain about lag, Ill be happy to take anyone for a ride that wants to check it out. If you want this setup just call SS and ask him for the Slowwrx Kit.
i i were to go this route, then if i go with the precision turbo or a simple perrin supplied gt30r, then swapping to a 35r is i so desire would simply mean to take the turbo off and put the new turbo on (and tuning obviously) now if i wanna run a twin scroll setup, would i have to replace only the turbo and uppipe and retain all the other parts?
To run a true twin scroll turbo on the subaru, you would have to change the complete exhaust manifold to a divided one that seperates the exhaust pulses as they enter the turbo. By only changing the up pipe you will not achieve this as the exhaust pulses would all merge together and then have to be split up again going into the turbo. A true twin scroll setup would be a 4-2 and would never merge together untill going through the turbine housing. If its not a true divided header setup the twin scroll turbo is useless, and adds nothing.
to answer youre first question, yes you can just switch back and forth between a 30 and 35, I'm not sure who is making a rotated twinscroll setup as of right now, I think I read somewhere that aps and UR are both working on one, I personally have never been a fan of aps, it seems to me that they have screwed up more turbos than they have got right. Matt
If someone will design a 30R twinscroll kit that works I will be all over it, although I'm not sure how much more power band I can use, but quicker spool sure wouldnt hurt my feelings. Matt
what about intercooler fitment with the perrin kits? would it fit with a TMIC? If i decide to go with a FMIC, could i buy an APS dr525 (or any other FMIC kit that is designed to fit with the stock mount turbo) and expect it to fit? or would i need additional piping?