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Discussion Starter #1
Just bought a Cobb 20g for my 05 STI. It will be tuned on 91 pump gas and E85, which is what my car is running now with a turbo that shit the bed last night. Not naming names, but I definitely should have gone with a more established and affordable company. Turbo only lasted 4 months on a ridiculously conservative tune (370hp/375tq on E85 @ 20psi).

The Cobb turbo was on the low side for cost ($1200) considering my other options were in the $1800 range. I heard Tamioka builds these for Cobb as well, and not sure if that is rumor or not. I wanted a quick spooling turbo with a bit more top end than stock, and all my research pulled me in the direction of a 20g. Its gonna be stock location supported by a GrimmSpeed TMIC (which has been an awesome upgrade for sure and every bit as capable as the Process West). Never heat soak in Arizona unless your pulling over and over and over again. Anyways, just looking for some input on the 20g and how people that are running it like it. I understand power is nowhere near a rotated 30 or 35 with a FMIC, so everyone who is jumping at the bit to pull that card can hold off. I drive my friends built rotated 35 and know all about 600whp. I dont want that. This is my daily and I dont drive in a straight line a whole lot.

Also, I was really on the fence between a Blouch Dom 1.5 or 2.5 and the Cobb 20g. Asked various mechanics and my tuner and all steered me away from Blouch which caught me off guard at first. That's kind of the gold standard in alot of shops so not sure why, but they talked me out of it. Has anyone been tuned on a Cobb 20g yet? And if not, for those running other 20g turbos, especially on E85, how do you like them?
 

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The 20G will be a good and fun turbo. I have tuned a Cobb 20G/TD05/8cm and a Blouch 2.5 XT-R. My results are below, both on E85. The only gripe I have about Blouch is their customer service, in my experience has sucked balls on multiple occasions.

20G on 05 STi


2.5 XT-R on 06 WRX. Boost and timing kept relatively low as this is a stock WRX 2.5L motor that we're trying to keep alive.



The GS TMIC, from the testing I've seen I would rather run a stock TMIC. I understand the Arizona heat as I grew up there. I FMIC will heat soak there:

TMIC testing (06 STI and Grimmspeed) - NASIOC

Grimmspeed TMIC, Splitter and Y-pipe - my experience - NASIOC
 

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To the OP,

Where are you in AZ and who is your tuner? I have had many tuners tune my cars in az(Archie at PSI, Phuong from wingzperformance, Clar Tuner, IAperformance, Goodspeedlab) and you still have other tuners like Evans at estune, UMS, Dynocomp, Vivid racing and a few more, like I said I just curious.

I don't know why people streeed you away from the blouch turbo. I's take a ball bearing turbo(1.5 XTR and 2.5 XTR) over a journal turbo any day.

Do a search on my name(username) I put down 319whp/411 lb-tq mustand Dyno on my stock turbo/stock intercooler. I will be dynoing the car again in the winter and I am sure that I will pick up a few extra HP/lb-tq specially after my modified catback. PM me.
 

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Seems like everyone nowaday wants a Dominator turbo but the 20g dynos look like they have more power in them. What am I missing? Assuming the Dom XTRs spool faster, and that's what people are looking for I guess?
 

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Seems like everyone nowaday wants a Dominator turbo but the 20g dynos look like they have more power in them. What am I missing? Assuming the Dom XTRs spool faster, and that's what people are looking for I guess?
A dom 1.5 should spool slightly slower vs a 20g (depending on the size of the 20g) but make more power with equal tuning. Dyno plots from different dynos, different tuners, and under different conditions really make it hard to get an accurate comparison.

Look up TopSpeed Motorsports dom 1.5XTR vs 20g XTR comparison. The 1.5 wins in basically all categories, with spool being almost the same.
 

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Discussion Starter #7
All stock location turbos on an STI are going to make roughly the same power, unless your playing with fire, so HP and TQ numbers aren't really my concern, i know it'll make around 300 on pump, and around 400 on corn. What i am concerned with is spool up and reliability. The spool up part led me to the 20g, and the reliability part led me to Cobb; even though this is a brand new product from them. Cobb pisses me off in many ways, but one thing they do right is test and eval the shit out of their products before they release them for sale. Kind of like APR is to VW/Audi, Cobb is to Subaru. I had been eyeing a Precision, FP Green, and Blouch before choosing Cobb and the only thing that led me to Cobb was their reputation for testing, eval, and reliability; not to mention Cobb parts dont scare people away as much when it comes time to sell the car which may be very soon. Got to get it running nice before I make that call though.
 

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Discussion Starter #8
To the OP,

Where are you in AZ and who is your tuner? I have had many tuners tune my cars in az(Archie at PSI, Phuong from wingzperformance, Clar Tuner, IAperformance, Goodspeedlab) and you still have other tuners like Evans at estune, UMS, Dynocomp, Vivid racing and a few more, like I said I just curious.

I don't know why people streeed you away from the blouch turbo. I's take a ball bearing turbo(1.5 XTR and 2.5 XTR) over a journal turbo any day.

Do a search on my name(username) I put down 319whp/411 lb-tq mustand Dyno on my stock turbo/stock intercooler. I will be dynoing the car again in the winter and I am sure that I will pick up a few extra HP/lb-tq specially after my modified catback. PM me.
I live in the west side of Phoenix, and the shop is Soulless Performance. I had a really bad experience with Goodspeed and since Clark is somewhat associated with them, i kind of wrote all of them off. I have never and probably never will pay for an Etune so all of those guys are out. I like being able to see the person when and if problems occur. Dynocomp has been very helpful and knowledgable, but at $130/hr labor i'll leave them to the Porsche and GTR crowd. Soulless is reasonable, has super helpful mechanics, and a very knowledgable tuner all in one spot. They are installing my Cobb 20g and retuning for 91 and E85 for free because they feel bad about a turbo they had sold me becoming such a disappointment. That's unheard of in the auto performance industry, and I'm far from a loyal customer.

Now on the BB vs Journal part, I dont have enough experience with either to make that call. You will find horror stories for both all over the internet. More for the BB actually since it is a much more common platform. My turbo that just died was a BB turbo, but my friends has been running strong for over 2 years now at over 30 psi. I have a feeling that they steered me away from Blouch because they don't make as much money selling Blouch as they do with other companies, but I know for a fact that Cobb doesn't discount to smallish shops ( or any shops for that matter) so that wasn't really a factor. Ive heard alot of good and alot of bad about Blouch. Their turbos perform and they have made a name for themselves in the Subaru world. But they are full of themselves; even more so than Cobb. Companies that focus primarily on turbos usually have pretty shitty customer service. FP and Blouch are about the same when it comes time to man up. They deal with alot of pissed off people, so eventually they all just become anti customer after the sale. Yet another reason I went with Cobb.

My contract is up in AZ and I will most likely be moving back to CA within a month or two. So all of the local shops out here will be a distant memory soon. It sucks going back to all the restrictions of CA, but there are so many awesome shops out there that it almost makes it worth it.
 

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The 20G will be a good and fun turbo. I have tuned a Cobb 20G/TD05/8cm and a Blouch 2.5 XT-R. My results are below, both on E85. The only gripe I have about Blouch is their customer service, in my experience has sucked balls on multiple occasions.

20G on 05 STi
Image Link


2.5 XT-R on 06 WRX. Boost and timing kept relatively low as this is a stock WRX 2.5L motor that we're trying to keep alive.
Image Link



The GS TMIC, from the testing I've seen I would rather run a stock TMIC. I understand the Arizona heat as I grew up there. I FMIC will heat soak there:

TMIC testing (06 STI and Grimmspeed) - NASIOC

Grimmspeed TMIC, Splitter and Y-pipe - my experience - NASIOC
I agree with this 100%. I have a 1.5 and love it. No E85 yet but hopefully soon. But the customer service is horrid. Mike is a straight up jerk. They offer a warranty but don't stand by it. Mine blew up on the first pull on the dyno and sent it back and he blamed me for it being bad because I installed it wrong which I didn't. He wanted to charge me 800 bucks to fix it which is half what I paid for it. Ended up paying 400 to fix it cuz he knew I was on to him. Should of been covered by him but I just wanted my car running. Long story short if you go blouch just pray that it's good. It's an awesome street turbo especially for the twisties. Just the right amount of power
 

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Discussion Starter #10
The 20G will be a good and fun turbo. I have tuned a Cobb 20G/TD05/8cm and a Blouch 2.5 XT-R. My results are below, both on E85. The only gripe I have about Blouch is their customer service, in my experience has sucked balls on multiple occasions.

20G on 05 STi
Image Link


2.5 XT-R on 06 WRX. Boost and timing kept relatively low as this is a stock WRX 2.5L motor that we're trying to keep alive.
Image Link



The GS TMIC, from the testing I've seen I would rather run a stock TMIC. I understand the Arizona heat as I grew up there. I FMIC will heat soak there:

TMIC testing (06 STI and Grimmspeed) - NASIOC

Grimmspeed TMIC, Splitter and Y-pipe - my experience - NASIOC
Theres a real mixed bag of info and reviews on the Grimmspeed top mount. Moto IQ tested it and loved it. A few individuals have claimed it killed power and or is useless. What i know is that when it was installed and my car was dyno tuned at over 100 degrees it did not cause any loss in power over 10 pulls. At the time my tuner was using a tiny shop fan to cool the engine bay as well, so the intercooler was definitely having to put in some work. Never had the chance to test the stock top mount to the same standard, but something tells me it would've been a different story. Testing intercoolers can be a very tricky endevour. I think Moto IQ went about it better than just about anyone else did in their garage though. As far as the guy who lost 30 hp or whatever, his car probably needed some more troubleshooting or he received a bad intercooler. If the Grimmspeed was a crap product, i would have found out by now.
 

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I haven't tested it personally, but the first review posted was done by AirBoy. If you've done any research on tuning, you'll see that he's a pretty respected dude when it comes to this stuff (I use his spreadsheets). The second was done by a shop in Colorado who is also a personal friend (and a racer) and he knows what he's doing with a Subaru (also a Cobb ProTuner)... So, not a garage. Grimmspeed was not happy with him. Also, I believe another tuner buddy of mine wasn't too impressed and only ran it on a certain RSTi due to the ridiculously low cost they gave it to him for to test with. With that said, without testing back to back with a stock intercooler, there's really no way you're going to know and I'm guessing you don't want to know. :)

I do know Crawlerado couldn't get that intercooler to cool down, once heat soaked, with those thick cast end tanks. This is one of the reasons I had ETS build me one of the hand made TMIC's it didn't carry near the heft of cast ends.


Both the graphs I posted were using ETS TMIC's. The WRX, back when I tuned him on a VF39, was running the ETS TMIC in this video @2:12. If my MAF ends up not being large enough for my new turbo, I am going to switch to SD and put a temp sensor in the TMIC and get some data.

 

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Discussion Starter #12 (Edited)
3 cobb 20g turbos were tuned over the past week and I am pretty excited for Monday to say the least. A stock 07 WRX put down over 350 at the wheels on 91 octane at 18psi. Full boost for all 3 was reached around 3700 rpm. My car will be one of two at the shop to be tuned on ethanol, so I'm expecting low to mid 400 hp and tq based on the 91 octane numbers; especially considering that the car was a bone stock WRX and my car is a pretty heavily modded STI.

On the GS top mount, if and when i ever notice it is a weak point in my build it will be history real fast. The only thing keeping me from an ETS front mount are my jdm fogs. I had almost bought one initially but held off. Until then I'm giving them the benefit of the doubt. I will note that mine is a bare silver model, not the fancy anti heat black coated one. Maybe that black coating is causing more harm than good. I spent an hour wrapping mine in DEI gold and maybe thats helping. Dont think that I'm supporting grimmspeed in any way either. I could give a rats ass if they went under tomorrow. I spent $600 on the top mount which is pennies compared to the rest of the parts in that car, so if i have to spend another $1500 for a product that performs better I would in a split second. For the moment though I dont have a reason to.

And yes I know they offer custom piping options to retain fog lights with a fmic and no I dont want to spend the extra money for them. When and if I want to make some real power, the fogs will go bye bye.
 

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Discussion Starter #14 (Edited)
How much does a stock STI put down on that dyno?
Im not sure, but my E85 tuned STI made 370hp/375 tq @ 20psi on the same exact dyno. They ran a stock GTR and stock Corvette ZO6 and the numbers were very close to what was expected. Its a dyno dynamics dyno by the way. Unfortunately they have never had a stock STI to test on it. Even the new STIs that show up have something or other already modified.

That WRX made more power than the STI he tuned, and the STI had a few mods as well. So maybe the 2.0 makes more power than the 2.5 with that Cobb 20g, either that or the dyno was off. Im gonna talk with them about it on Monday, just noticed the numbers on a text from one of the guys at the shop. Theres a possibility that they got the car mixed up. They've tuned 5 Cobb 20g since they came out, and theres two more waiting til Monday so it could have been a mix up. The numbers definitely seem high for what it is.
 

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Discussion Starter #17
On the stock turbo? lol
Unfortunately not. Stock turbo cars consistently made more power than my Cavalli stage 2, which was a 54lb/min turbo by the way. My turbo had a slight oil burning issue from day one though and considering it crapped out after 4 months, it was obviously a bad apple. My turbo also wouldnt get into boost until almost 5000 rpm. It felt alot stronger than 370 ish hp and tq though when it was in boost, but thats besides the story. I was warned by many many people not to go the route I did, but I didn't listen and bought it anyways. Live and learn. The 20g is tried and true, and while there are other turbos that make slightly more power, how many of them have the warranty and reputation that Cobb does? I personally think the 20g is one of the most under-rated turbos for the EJ257. Yimisport and many other shops have made unusually high power with them boosting under 4000 rpm. It's the right sized turbo for the EJ motors. Subies like em just as much as DSM do. In my far from professional opinion the 20g is the best stock location street turbo, and the 35 is the best rotated turbo for these engines. The smaller td05 wheel and 8cm are a good combo, despite what many people believe.
 

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Discussion Starter #19 (Edited)
Wait, stock turbo cars made more than 370? That sounds like a verrrryyyyy happy dyno!
Its very common on E85, check proven power bragging on Nasioc. VF turbos make decent power, they just lack top end. Now that I think about it, VF series turbos make very similar power to 20g, Dom 1.5, etc but the power curve falls off alot harder than a 20g or bigger aftermarket turbo, and the torque just isn't near as strong. Peak HP number wise though, they are pretty close. I'd never have a VF pushed past 20 psi though, and even that would make me weary; 18psi max realistically. Now with a 20g or Dom 1.5/2.5 I wouldnt worry one bit boosting near 25 psi; although forged pistons would be done at that point. I'm guessing my Cobb 20g will be tuned at around 20-22 psi on E85, and about 18 psi on 91 pump since I am on a stock motor; a very healthy stock motor I might add. (knocking on wood)

Sorry been editing the hell out of this. Your rotated 30 on E was the original direction I wanted to go. The 3071 I drove was really nice, but it was on pump gas. I didn't have the funds to go rotated at the time though, so here I am. The 30 series turbos are definitely another badass option tossed in there with the stock location 20g and rotated 3576.
 

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Its very common on E85, check proven power bragging on Nasioc. VF turbos make decent power, they just lack top end. Now that I think about it, VF series turbos make very similar power to 20g, Dom 1.5, etc but the power curve falls off alot harder than a 20g or bigger aftermarket turbo, and the torque just isn't near as strong. Peak HP number wise though, they are pretty close. I'd never have a VF pushed past 20 psi though, and even that would make me weary; 18psi max realistically. Now with a 20g or Dom 1.5/2.5 I wouldnt worry one bit boosting near 25 psi

Oh god. How does less torque, less boost, less everything come out even pretty close. I can say from experience, they aren't. Not really worth the reply :(
 
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