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Old 09-18-2010, 12:08 AM   #26
kcpaz
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Quote:
Originally Posted by Kostamojen View Post
If I were you, I'd look into some of the factory JDM twin-scroll turbos for your application (vf37, etc.)


Note: I'm not a turbo guy, I don't keep up with the turbo related stuff. So my opinions are possibly out of date.
I agree with you. No need for anything exotic or expensive. VF36 or 37 on a 2.5 gets my vote.
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Old 09-18-2010, 12:15 AM   #27
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One question I have is related to superchargers. Has anyone done successful supercharged 2.5 that makes over 300 WHP? I'd trade off ultimate top end for good 3000 to 7000 rpm powerband
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Old 09-18-2010, 12:22 AM   #28
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somebody mentioned a company that offers a supercharger kit in my Boxster thread. If I weren't on my phone right now, I would post the link...
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Old 09-18-2010, 01:30 AM   #29
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Hmmm...what about a supercharge JDM 2.0L v7?

-Britain
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Old 09-18-2010, 11:03 AM   #30
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How about a high compression jdm 2.0 build? Not super high, but a little higher than normal compression on a boosted motor will provide for a lot better throttle response. You not needing or wanting gobs of power, this could easily be built and be totally reliable. Having power ASAP would be a lot better for your purposes. High Compression turbo motors are fun. I knew a few people with High Compression Sr20's back in the day when I had my swapped 240, and I always wanted to do it to mine. They were just so "quick". Turbo lag was non-existant and response was nucking-futs. I can only imagine what it would be like to have my sti building full boost 600-900 rpm sooner; and with your car's super low weight, the response would be astonishing
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Old 09-18-2010, 01:30 PM   #31
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^^ That is the route I would be taking if I were building for XP and not FP. Probably not a EJ20 though. Supercharging would be another viable option, but it's alot of development work for a relatively unknown amount of return.

Jay
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Old 09-18-2010, 02:17 PM   #32
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Quote:
Originally Posted by Grantsfo View Post
One question I have is related to superchargers. Has anyone done successful supercharged 2.5 that makes over 300 WHP? I'd trade off ultimate top end for good 3000 to 7000 rpm powerband
Grant,
We should talk. You still got my email?
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Old 09-19-2010, 03:54 AM   #33
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Ok, I am going to go JDM STI 2.0L EJ20.

On that thought, should I go v7 or v8? As I understand it, the V7 has forged pistons, but the V8 has better flowing heads, higher redline, and better crank. Also the V8 has higher compression.

I also need to determine which turbo will work best for my application. I don't mind running a custom turbo and I would like an external wastegate. Is it worth doing twin-scroll? The header design I have in mind will be less than 18" from the exhaust port to the turbo and will be equal lenght.

From the turbo, I will go directly into an air-water intercooler and then directly into the intake (flipped). There will be very little bends and very look piping.

I am also considering using the same Leaded 110 Octane Race fuel that I am currently using. Either that or E85, which ever work best.

-Britain
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Old 09-19-2010, 10:41 AM   #34
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i started typing a responce this then came across this thread
http://forums.nasioc.com/forums/showthread.php?t=93659

people making 1.8 bar at 3100 on a v8+vf37 in a stock location

the guys in this forum are really good at putting weird things where they don't necessarily belong but tuning advice will be all over the place

call mr bailey and ask the fuel/turbo/engine question
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Old 09-23-2010, 04:43 AM   #35
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1) You need AVCS. Period. AVCS rules under 4k, where you'll be a lot.
2) You can run higher compression than stock, and likely want to if running E85
3) You want a 79mm crank for your desired powerband (the crank in the EJ25x). THe 2.0L rod:stroke ratio is designed around high RPM. The 2.5L rod:stroke ratio is MUCH better with torque, even if paired with the smaller bore. I would not design an engine for your purpose around the 75mm crank on the 2.0L or 2.2L engine. The 79mm crank matches your desires much better.

I think the ideal options would be:
2.0L block + 2.5L crank + custom ~10:1 pistons to get the height right + JDM AVCS heads (~2125cc)
2.5L longblock split it and put in ~10:1 pistons (~2460cc)

Turbo size has already been mentioned. vf34, 16G, maybe 16GEvoIII max.


2.1L vs. 2.5L comparisons:
http://forums.nasioc.com/forums/show....php?t=2051473
http://www.gruppe-s.com/stuff/21Stage2SB.jpg

These are larger turbos, and the 2.1L in these do not have AVCS, which is worth 2-300 RPM in spool. These are nice comparisons because they are both same turbo on the same dyno. The Motion one isn't exact same config, but the older Gruppe-S one is (but with a MUCH larger turbo than you're going to want to use).

E85 road dynos of turbos the size you're looking at:
2.0L: http://forums.nasioc.com/forums/show....php?t=2058626
2.5L: http://forums.nasioc.com/forums/show....php?t=2007990

Tuning house Dyno charts don't work well for looking at spool area. They load VERY differently than the road. Some do alright, but most do not. Look at where the road dynos are making 200 torque, as these will be more accurate for looking at that area of the curve:
2.0L ~2900
2.5L ~2600
A 2.1L will be in-between. Higher compression will push this number lower. Also, tuners don't really like to start pulls at 1500 RPM or anything, so sometimes this can lead to inaccurate torque numbers at very low RPMs.

Another thing to keep in mind is that these are all AWD with probably 20+% driveline losses. You'll be more than 205 torque to the wheels at decently low RPM on any of these engines. You'll definitely be better off than your 205 torque engine, but I'd assume you'll be lower torque at VERY low RPMs. Don't know how often your south of 2k, or the exact shape of your old engine's torque curve, but there's no replacement for displacement at the extremely low end unless you want to talk a TD04 on a 2.5L. Those will hit 200+ torque immediately, but they are topped by 5k. You can't get around turbo cars having smaller torque-bands than N/A cars. However peak torque of 350 instead of 200 probably makes up for it.

TD04 on 2.0L and 2.5L for reference:
http://forums.nasioc.com/forums/show....php?t=1998355

The 2.5L will likely be cheaper, as the easiest way to get all the parts for 2.1L will be a JDM swap, then split and replace pistons & crank. You would get twinscroll if you get a v8. The v8 twinscroll header is quite good.

JDM vf37 dynos (pump gas):
http://img13.imageshack.us/i/kotir.jpg/
http://img535.imageshack.us/img535/4774/scoobystas.jpg

Imagine those with E85 and the torque curve shifted left a bit from the longer 79mm stroke. I really think that's your ideal (Subaru based) motor for the XP classing. 2.5L is a cheaper fallback but clearly superior for the flat weight racing.

Last edited by Concillian; 09-23-2010 at 11:34 AM.
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Old 09-23-2010, 12:41 PM   #36
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Thank you Concillian...by far the most informative post I have read anywhere on this forum regarding what I am looking for.

I have decided to source a JDM v8 Spec-C and will run it with either E85 or Sonoco 110octane leaded (which is what I am currently running). I will be running a very short equal lenght twin scroll header and air-water intercooler. Should be a good combination.

I like the 2.1L option, and will keep that in mind down the road if I desire more torque down low.

I will document the build on here once I get started.

-Britain
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Old 09-27-2010, 02:31 AM   #37
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Quote:
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I have been lurking on here for some time now to gather information, parts, research, etc. I figured it was finally time to introduce myself and the direction that I am taking. I would also like to get some opinions from people here.

I run a Porsche 914/6 with a 2.7L 6-cylinder motor. The car currently weighs 1700lbs and has 205hp/205ft-lbs at the wheels. It runs full race slicks front and rear, has a custom 2-speed transmission, and used 110 octane race fuel. Here is the car:



Now, the reason I am here. I am currently looking to sell my 2.7L 6-cylinder Porsche motor and convert the car to a Subaru powerplant. There are several reasons to do this: cost, power, less weight, new technology, fuel injection, etc.

There are several 914's that have been converted to Subaru power, however I want/need to build one that is a dedicated AX car. Therefore, I need to decide the motor configuration that would suit the application the best. Remember, I am not looking for all out HP, I need good torque and good throttle response. The car does not weigh very much and I have less than 10% drivetrain loss.

Now, here is the kicker. All the SCCA rules for AX are built around displacement which in turn dictates the minimum weight. I know that a EJ257 2.5L motor would be an awesome choice and is actually the one that I am leaning towards. However, what can I do with a JDM 2.0L V7? The smaller displacement would allow me to run lighter, but can I get what I am looking for out of that motor?

Little background. I have talked with Tim Bailey at Cobb Tuning Surgeline in Portland. He will be doing the final tuning once I have the conversion completed. I actually have already bought his Hydra ECU and E85 injectors/fuel rails for use on my car. In addition, I will be running an air-water intercooler set-up and custom ball-bearing turbo. I want the power to come in around 3000RPM and the motor to redline at 7300RPM (same as my car currently which will keep my same gear ratio's).

I am very interested to hear your opinions,
-Britain
Looks good mate, however the clearance may be an issue - hopefully not.
I have sent through the specs so give us a call on 0242 60 7977 or email alex@hyperflow.com.au once you get that other work complete and measure up the space.

Regards
Alex
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Old 09-27-2010, 02:42 AM   #38
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Will do. I need to get my current engine sold and will purchase a JDM v8 Spec-C. After i get it in the car, I will be able to determine the ground clearance.

-Britain
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Old 09-27-2010, 02:44 AM   #39
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Will do. I need to get my current engine sold and will purchase a JDM v8 Spec-C. After i get it in the car, I will be able to determine the ground clearance.

-Britain
Nice one, look forward to hearing from you - and to see some more photos.

Regards
Alex
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Old 10-05-2010, 02:59 PM   #40
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Any more developments? I'm looking at a couple options including putting a blower on the Porsche motor but man Subi just seems so much more straight forward! I have more and more people warning me away from turbo for AX so I really want to see how this turbo setup on 914 AX works out.
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Old 10-05-2010, 04:21 PM   #41
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Grant,

If you are so worried about the turbo lag (IMO you shouldn't be), why not look into a Subie 6 cylinder. The EZ motors are light, compact, and make good power. Or, for even less money, the EG33 makes good low end torque, and used engines can be had for as cheap as $500. If I were going to use a blower on anything, it would be a Subie 6, not an M96. Just a thought. Also, The Subie 6's and 4's are interchangeable as far as engine mounting and adapter plates so if you wanted to try a 4 cylinder turbo first and see how it goes, and then later decide to change to the 6, it would be a bolt-in affair.
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Old 10-05-2010, 04:24 PM   #42
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On a completely unrelated note, Britain has yet to confirm me as a friend on Facebook. ...........
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Old 10-05-2010, 06:21 PM   #43
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Grant,

If you are so worried about the turbo lag (IMO you shouldn't be), why not look into a Subie 6 cylinder. The EZ motors are light, compact, and make good power. Or, for even less money, the EG33 makes good low end torque, and used engines can be had for as cheap as $500. If I were going to use a blower on anything, it would be a Subie 6, not an M96. Just a thought. Also, The Subie 6's and 4's are interchangeable as far as engine mounting and adapter plates so if you wanted to try a 4 cylinder turbo first and see how it goes, and then later decide to change to the 6, it would be a bolt-in affair.
Well if your conversion mount works out and I can get help with building and installing a 4 cyclinder supercharged subie I will likely go that route. I do have some fabrication and machine shop resources now that I may be able to use.
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Old 10-05-2010, 08:19 PM   #44
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Well if your conversion mount works out and I can get help with building and installing a 4 cyclinder supercharged subie I will likely go that route. I do have some fabrication and machine shop resources now that I may be able to use.
So you got my email? I wasn't sure since I hadn't heard anything.
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Old 10-07-2010, 06:15 PM   #45
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On a completely unrelated note, Britain has yet to confirm me as a friend on Facebook. ...........

Sorry about that, I get a lot of friend requests on FB and I have no idea who they are. You are added now. On a related note, be sure to add Where2Race to your list of pages.

-Britain
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Old 12-03-2010, 01:54 PM   #46
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Ok...time to update this thread and share some of the work I have been doing. The Subaru conversion in my AX car is in full swing. I have been working on it about a month now and have made significant progress. My goal is to have it running on the dyno by end of Jan. That will give me time to clean it up and complete some of the cosmetic items before the season starts.

For the engine, I went with a 2005 JDM STi v8 Spec-C. I sourced it from JDM Racing Motors out of Canada. It appears that it previously had an aftermarket ECU (probably a Hydra) and for some reason was converted to spark plugs using the same coil packs.

Here is the engine as it arrived:





First thing I did was strip it down to the longblock and start cleaning things up.



It is mated to the original Porsche 914 transmission with an adapter plate from Outfront Motorsports. Because I now have the Porsche bolt pattern, I could use my Porsche engine stand yoke...Bonus!


Last edited by Britain; 10-23-2012 at 02:00 PM.
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Old 12-03-2010, 01:58 PM   #47
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Here is a nice view...factory ported heads.



Ok, back to work...

I mounted a Outfront Motorsports alternator relocation kit to flip the alternator to the side. I also flipped the intake manifold as this is how it will fit into the car.



Now for the moment of truth...will it fit...more specifically, will it fit like I want it to. Here is the first stab into the chassis.



Last edited by Britain; 10-23-2012 at 02:00 PM.
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Old 12-03-2010, 02:17 PM   #48
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First thing I did was cut out the 914/6 bulkhead engine mount in front of the engine...you will see why I did this in just a bit. You can also see the nice stainless steel fuel lines that I installed here.



Back to the engine block. The JDM Spec-C came with an external oil cooler. This engine also had an additional sandwich plate for oil temp sensor. This stack was way too long and would put the oil filter at the lowest point of the car.



This is how long the oil filter mount bolt was to accommodate this length. I have since ordered and fitted a oil filter mount bolt from an N/A engine and it eliminate all the extra lenght so now I just have the oil filter mounted directly to the block.


Last edited by Britain; 10-23-2012 at 02:00 PM.
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Old 12-03-2010, 02:26 PM   #49
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I purchased the Synic Motorsports header which is equal lenght, but not exactly for a twin-scroll set-up.



With the header installed on the engine, you can see the engine mounts that I am utilizing for the conversion. They are actually for a Vanagon conversion, but with a little modification they fit just fine.



Back to the header...the first order of business was chopping off the pipes right after the merge collectors...getting closer to a twin-scroll set-up.



The only problem was that when I cut off the pipes, I was faced with a failed attempt at properly building a header. The merge collectors were not the highest quality that I have seen.



Little bit of time with the die grinder and they look much more acceptable now...and I bet the flow better.



Ok, now with the header mounted you can see my thinking on the positioning of the turbo.



With the engine back in the car and everyone suspended with straps, you can see how the turbo will fit just perfectly in the factory recessed firewall location.



To get the turbo in the correct orientation, I had to re-clock the compressor side. To do this, I took off the small retaining bolts/clips, applied a little heat and some motivation from a mallet and it popped right off.


Last edited by Britain; 10-23-2012 at 02:01 PM.
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Old 12-03-2010, 02:37 PM   #50
Britain
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Now that I have an idea where the turbo will fit and how the headers route around the engine, I could fab up the engine mount bar. The bar attaches to the Vanagon mount that I showed earlier and extends to the frame rails. At the frame rails, there are rubber bushings. Here is the engine suspended in the car for the first time.



Now I just have to connect the dots between the exhaust ports and the turbo...



Here is the turbo hard mounted to the engine mount bar. I had two threaded bungs machined that the turbos mounts to.





I found it difficult to source JDM uppipe and downpipe flanges for my use, therefore I just had them waterjet at a place down the street. I am running external wastegates so the internal wastegate port was blocked off. They turned out fantastic and if anyone needs a pair, just let me know and I can get them cut for you.



Using left over piping that I had cut off the header, I fab'ed up the connecting pieces for the header to the turbo.



Here it is mounted in the car...everything fits like a glove.



With the turbo mounted in this location, the gravity drain has no where to go to get back to the oil pan. I was very restricted on space, so I had to fab up a custom drain pipe using the oil coolant hard lines off the engine.



It is all downhill back to the oil pan...just barely.


Last edited by Britain; 10-23-2012 at 02:01 PM.
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