Opinions on which turbo to buy? or setup to reach my goals?

I did enough innovation with the Z... I think at this point I will go with what's proven. Now to decide on motor build... I hear the 2.35L motors are retarded fast but I want something somewhat practical lol maybe rev to 8k

 

You pretty much have two options when it comes to the block with us. Our SS1 which uses factory rod and crank, with coated CP pistons. That motor is something we sell probably 10 of a month and is very tried and true! Good for 450-500whp all day.

The second chose is our RR1 motor which is fully race born and bread. That motor is basically build to hold 600-650. We had one of those in Lucy our TA car..ran it for a full season, then pulled it out and put it in a customers car.....its still running flawlessly to this day. Those motors are stout and some of the best in the industry ( in my opinion anyway)

The heads on the Subaru really don't like RPM. Anything over 7500 is usually a waist of time on a 2.5, but it can be done. Cams, PNP, Springs, Retainers and such is needed for that.

Hope this helps.

~Cicio

 

The 2.35L is what I'm running in my car and while its a super strong motor its overkill for most setups.

 

I would have to say that the GTX series is far from proven. Interesting post from Perrin's testing:

Originally Posted by PERRINJeff View Post
With speculation of this turbo acting like a GT3582R, why DIDN'T it make tons more power, well I think that is a simple answer. While the GTX3076R flows like a GT35R, the GT35R has a much larger exhaust wheel and there for has much less back pressure as well as more potential to flow more air. So while the GTX3076R compressor wheel flows enough for tons of power, the GT35R turbine wheel needs to be in place to push past the 500WHP mark.

Here is the thread. Pretty good read.

http://forums.nasioc.com/forums/showthread.php?t=2110277

And another thread that popped up discussing the differences between the two platforms GTX vs EFR

http://forums.nasioc.com/forums/showthread.php?t=2131346

 

While the compressor wheel design of the GTX may not be proven the rest of the turbo certainly is. Beyond that his goals could be obtained by using the tried and true standard GT30 or 35R. The ball bearing design of the Garrett Turbos is proven it works well and rarely fails.

While the new EFR line intrigues me Ill let them get a year under their belt before I even consider jumping on board with those.

I personally have had enough of being a test mule for turbo companies.

 

I agree to some extent, although the gtx compressor seems quite capable the old turbine seems to be what is holding it back.

Initial testing and comparisons of the EFR8374 seem to show it outflowing and outspooling the gt35r. I am quite interested to see more from the EFR7670 as it seems that it might be a great option for people looking for street performance. With the gamma-ti turbine wheel, monster ball bearing cartridge, billet compressor wheel and completely redesigned 42 mm internal gate it should be a real street terror.

Even the old journal bearing Borg Warner turbos performed equal to or better than their Garret ball bearing counterparts. I can't imagine these new EFR ball bearing turbos will be any different.

 

fwiw.... perrin tested the new gt35r with the old outdated (t31) .63ar turbine housing. That is a horrible comparison, as the new aero packages need the newer turbine housings to work. I am with Matt on this one, I too will have to wait and see what the EFR turbo's do. In all my experience high boost BW turbo's fall apart pretty quick, atleast the older stuff did.

 

At Scott and Doug's recommendation, I bought the GT35R dual ball bearing turbo from Tial with Tial's SS v-band .63 exhaust housing.

That turbo was the tits......it spooled just as fast as my old 18g on the 2.0L yet made gobs more power. Hit 21-22 psi by 3800 rpms on a cheap budget built 2.5L.

IMO you can't beat that standard dual ball bearing Garrett for what it could do....the street manners on it were very impressive. Yet that 'little' housing cracked an impressive 10.3 in the 1/4 on slicks.

 

I would have to disagree on the BW stuff falling apart at high boost. Many of their applications were used on OEM applications that were used on diesel vehicles that went from 0 to 50 psi over and over again all day every day. Think of a delivery vehicle or garbage truck making many many stops every day. The turbos all have to pass OEM manufacturer tests before being released that many companies like Tial are able to ignore in the performance market.

These new EFR were designed specifically for gasoline performance applications. In fact the twinscroll turbine housing made for the new EFR were sent back to the caster because they were not up to standards. This has resulted in a delay of the release and probably cost BW some lost sales, but they wanted all products to meet their standards.

You guys should check out the Cosworth EFR torture test they performed. It is posted on youtube and is pretty crazy.

 

I understand your point but I know quite a few DSM owners (6 right off the top of my head) with Bullseye BW turbos they have crapped out on them after 15-20K miles. They were boosting 28-35 psi iirc.

 

It has come to light in the past year that Bullseye was making some of their own components. Most notably the compressor wheels and housings. Their billet stuff is supposed to be decent though.

 

Not trying to start a fight but that would be like blaming Garrett if a FP HTA 35R fell apart.

Edit: Mike beat me to it

Also, BW Turbos are very reliable when they come from BW. What do you think are in the turbo charged VAG cars?

 

Looks like we need a separate turbo thread? So that Bullitt's thread can stay on track...


All interesting information tho.

 

I didn't know Bullseye made some of their own parts.

 

They have always made their own turbine housings. Many of the BW turbos were not available in a t3 housing and I believe that is where they started. They then branched out to some of the wheels.
But I believe all of this is good related information to help this (and future) customers make a more informed decision. Neither turbo has had a ton of results yet. Both look like they could be promising. Again we should have some results of our own on the smaller EFR6758 at the end of the month. Pretty exciting stuff. Seeing the EFR in person really let's you see the quality and design work that went into them.

 

Awesome guys!!! This is the type of discussion I was looking for.

 

I am not a fan boi of any turbo brand including the PTE that is on my car.

My friends at APR swear by the Garrett GT and GTX series turbo. The GTX looks very promising.

I have seen the BW EFR turbo and it looks extremely nice and innovative. Down to the internal WG ports. Again, the guys at APR are very excited about this line of turbos as well.

I guess only time will tell. I just wish someone with a Subaru would hurry up and put one on their car.......oh wait

 

Soon as I get my transmission done I am planning on it! But bigger than most will use on the street

 

Edit....ish

I just realized you are talking about the 2.5 block with the 2.0 crank, thats a whole different setup than what I'm running. I'm not totally sold on those yet. Thats a very long conversation though.

 

Not totally sold on those either. They seem like an interesting combination, but I think for the street you are still better off with a well built 2.5 liter motor or even the 2.7 liter stroker motor and get a good bit more low end grunt along with quicker spool up.

 

2.6L all day every day.. The destroked 2.5L is cool idea on paper, but in real life we have seen no earth shattering reason to do it.

As for the OP original question, I have tuned so many different turbo combinations on suby's here at the shop.

But as of lately there are only two that we feel are actually worth while. The blouch 20G-XT with 10cm housing, and our TopSpeed GT35r Rotated kit with the tial .63 housing. Every single other turbo I have tuned or we have tested always seemed to give up in some areas for little gains. These two hands down are our favorites. Great powerbands, and both are awesome to daily drive on subaru's.

That being said the new GTX3076 is supposed to spool faster then the GT35r and make the same power. So we will be testing it soon here at the shop, but will hold off on any recommendations till then.

Here is a dyno comparison of the Blouch 20g-xt vs our rotated gt35r kit. On the dyno the spool up difference is minimal, but on the street the 20g has quicker boost response of course.

 

Does that 20g have a fmic? What kind of race gas/meth numbers would you see with if?

 

tmic

 

08+ STI OEM TMIC right?

 

How much slower of a response would you have seen with a fmic on it? Maybe a few hundred RPM?

 

Very Very little with a properly sized front mount.

 

What would you consider a properly sized front mount for the 20g?

 

Nothing bigger than a Perrin. Smaller than that would actually be better.

Something with a core capable of supporting 500whp is all that you really need, as well as properly sized piping.

 

Some really good discussion on this thread as well. Some dyno graphs, some comparisons. But lots of good discussion.

http://forums.nasioc.com/forums/showthread.php?p=33267406#post33267406

 

So Doug what would I be gaining from a stroker on this motor? I mean your talking only adding .2L on this platform. Are you sleeving the block at that point or still playing with the crank? Would I be able to gain a 8000rpm red line? How would this affect the turbo selection? I would guess that we would go to a 35R or 40R? What performance gains would we get vs. price?

Thanks,

Mike

 

Mike by addind displacement you can run a larger framed turbo, and still have nice street manners. Though overall power production will remain closely similar to a std 2.5L

8k rpm can be done, but requires the right package to work and make power there.

 

Do not waist your money on a stroker kit, if you want to get a real gain for that kind of money I would sleeve it and have 102mm pistons made (Ross is a very good piston). Stock crank will work perfect, set of forged rods and have a competent shop port your heads as well as several other ins and outs. That would handle anything you throw at it once again provided the tune is right.

As far as the turbo is concerned, don't waist your time on a stock mount anything, go rotated that is the only way you will be happy. Borg turbos are one of the most reliable turbochargers available as well as Garrett, anytime you get outside companies modifying OE components, you WILL have problems. I am currently building two systems using the EFR series turbos, I will let you and everyone else know how they work. For my reccomendation, I would go Borg all the way. By the way, all of our kits use Borgs but I have built a ton of kits using Precision, Garrett, and Holeset the borgs seem to always out perform.

 

^^^^I would have to respectfully disagree with Borg turbos out performing other turbos on Subarus. But I disagree even more with the 102mm pistons.

I think Doug is going to post a response to this so theres no reason for me to.

 

I'm curious as to how the new 2.5L is going to play out performance wise. Small bore long rod might be the answer afterall...

 

Thought I would share one of the few 2.35l graphs I have seen. It is a Garret GT35R on a 2.35 liter. Maxwell Power built and tuned I believe.

 

Mike you are the link master.... just about every other post of yours is a link to something somebody else has done.

That 2.35.. doesn't start making power till 6krpms and then has 3k rpms of power band. Not sure if I see the point, cool I guess if you want to be different. However for a daily driven car that would not be much fun.

Matt is correct... I had made a large post of why the stock crank with 102mm bore doesn't work well on a Subaru but deleted it. I know the first race motor I built was built that way.

If your interested we can chat when you swing by the shop, I would be more then happy to chat with you about it.

 

There is a reason why subaru is dropping piston size and adding stroke, but what do they know.

I never understood the hype in the subaru world with the ultra short stroke's. Take the Evo for example, factory stoke is 88mm compared to the sti's 79mm. The EJ motor doesn't need more bore less stroke, it needs the exact opposite kudos to fuji for correcting it on the Gen3 motors.

 

Not a motor we have had any desire to build to be honest. So I have no direct experience with this motor and I wanted to try to help the OP find some results from one of these motors.

But I am sure you could post up some results from a 2.35 liter Subaru motor that you have built and tuned?

 

Here is a 20g vs one of our S256 kits that we built and tuned on a WRX hybrid motor on pump gas 93 octane. The 20g was tuned by another shop here in Atlanta. I am not sure which one. You can see before 4000 rpms the 20g has it but after that the rotated kit just pulls away all the way to redline. And remember that was on pump gas for the small Borg Warner. The WRX also has stock WRX cams and heads, so power dies off pretty good after 5500. S256 rotated was done in 3rd. I believe the 20g was done in 4th which is what the customer requested. Both cars had 6 speeds.



Edit: Looked back, the 20g was only on pump gas, not pump and meth. So pretty good comparison of 20g vs a 30Rish sized rotated Borg Warner turbo kit 2.5 liter.

 

Here is that same turbo set up on a stock Sti with 180,000 miles. Again we built the rotated kit and tuned the car. You can see it held power better till redline. I tuned this car quite conservatively with very little timing and air fuels on the rich side. All of these graphs are 3rd gear on 6 speeds.

 

Theres a couple of different ways to arrive at 2.35 liters for those that don't know.

One way (Maxwell Powers Way) is to put a 2.0 crank in a 2.5 liter block with custom rods and pistons. You can rev this motor pretty high since the stroke is short.

The other way (The way my current motor is setup) Is a 2.2 Closed deck Block with a 2.5 crank and Wiseco Stroker pistons with STI Rods. With proper oiling mods you can rev this pretty high as well, you also get the benifit of having thicker cylinder liners and a closed deck. A few guys have made 800hp without sleeving these motors.

 

2.2 based motor is much cooler than a destroked 2.5 in my opinion.

 

Here is an interesting little turbo. It is a stock location 3076R on 100 octane on a 2006 Sti with a topmount intercooler and an external wastegate. This is an "Airboy" dyno of the car in 4th gear.

 

Very interesting Guys!

Basically here is what I will be going for.

GTX3076R or GTX3582R or Similar sized rotated turbo kit.

Built block and built heads...

My Goal: reach max boost early as possible and maintain power to 8k rpm.

I believe going to a larger displacement will help me run a larger turbo but possibly at the cost of not reaching the 8k rpm goal and possibly the quick spool time goal depending on turbo size.

Going Smaller displacement will not meet the goals I am looking for. Shifting the spool time way to the right on the graph. The Tach on the Car only goes to 8k and rev'ing to 9k+ even though novel like my old s2000 is just not practical for me. This is a car that will be making long trips and daily city use. So bad gas mileage and an ineffective lower end torque will not get me what I am wanting out of this system.

I think what its going to come down to is finding the right combination of turbo size and displacement. I am not going for the highest HP possible but for the most power under the curve... Like I mentioned before I would like to be in the 400-450awhp range. Which ever setup will get me there within my parameters is going to be the kit/shop I go with.

 

In all honesty if you are just looking for 400-450 on pump the GTX3076R is the turbo for you. Super fast spool yet makes the power of a GT35R. Listen to Doug....he's tuned more turbo setups and platforms than anyone on this board.....shoot he's tuned more Subaru setups than everyone on this board combined.

 

I had no problems with my lights and 180 custom did them out of NY but I found some local talent and she is REALLY good!!!! I have her contact information and I need to give her a call to work out the details. She also does CF wrap work and some buddies of mine have a guy who makes CF parts for them. I am going to try and hook up with these guys and see if I can help get us some CF parts people may want.

 

Coolbimmer that is were you are very wrong.

 

I said Subaru.

Doug's tuned more than Siegel and Siegel hasn't been on here (or replied at least) for quite a while

But don't see the point of your reply anyways. It means just as much as mine which isn't much.