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Old 06-08-2006, 09:51 PM   #1
STI8U
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Here is my setup:

MY06 STI Spec C Type RA (EJ207)
2.2L Stroker (2123cc)
HKS GT2835 twin scroll bolt-on turbo
800cc injectors
280L/h fuel pump
Autronic ECU
Water/Meth Injection
Power Enterprise V-Mount Intercooler
etc..
etc..

The car is a daily driver with casual track work...not a drag strip car.

Speaking with Kelford (who are local as I live in NZ ), they recommend one of two configurations:

1. 272/264 @ 0.010, 232/222 @ 0.050, .403/.377 lift, intake/exhaust
2. 264/264 @ 0.010, 222/222 @ 0.050, .377/.377 lift, intake/exhaust

They reckon option 1 will give maybe 10-15 more HP ATW, at the sacrifice of shifting the power band 300RPM or so...Option 1 is apparently very popular in the US with the 2.5L engine, but obviously I will have lesser displacement so I need to be careful.

My inclination is towards option 2, but after some thoughts/comments from others...
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Old 06-09-2006, 12:59 AM   #2
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....'built motor' forum FTW
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Old 06-09-2006, 04:33 AM   #3
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Moved to Built Motor...
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Old 06-09-2006, 04:56 AM   #4
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do those kelfords support AVCS?
btw, what stroker did you use to retain high rev limit?
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Old 06-09-2006, 05:45 AM   #5
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Yes they support AVCS - stroker kit is Tomei, uses a forged, palsonite treated crankshaft with 79mm stroke (vs 75mm stock stroke)...

These kits don't seem to lose any revability - this is a dyno graph of virtually what my setup will be, just using HKS stroker kit and running a higher CR (8.5:1 vs 8.2:1 for my setup)....as you can see the peak power is held from 6000RPM to 7500RPM, with my stock turbo setup power drops pretty quickly after 6500RPM...

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Old 06-10-2006, 05:30 AM   #6
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yeah what?
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Old 06-10-2006, 03:57 PM   #7
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Gor the the option 1. upgrade springs and retainers. I think this will help the top end alot. But you do have a small turbo.

Clark
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Old 06-10-2006, 07:46 PM   #8
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Quote:
Originally Posted by AZScoobie
Gor the the option 1. upgrade springs and retainers. I think this will help the top end alot. But you do have a small turbo.

Clark
Yeah, I agree with Clark here on the 272 duration cams. So, why such a small turbo on upgraded cams?
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Old 06-10-2006, 11:57 PM   #9
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The GT2835 IMO is not too small for my setup (remember, 2123cc not 2.5L)...385WHP as shown in the above dyno plot is more than enough for me, I'd be happy with 370WHP, given I'm currently making almost 300WHP on the stock turbo.

I've plotted on a GT2871R compressor map (closest thing to a GT2835) and the turbo can hold 1.6bar to redline no problems...the extra 129cc over the stock 1994cc will help make the turbo a little less laggy.

I'm not after a drag car, I'm after a daily driver that does some casual track work...so a balance between torque and power is required...

Hence why I favour the 264/264 cams...I'm worried 272/264 cams will make the car a bit laggy...
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Old 06-11-2006, 12:31 AM   #10
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Quote:
Originally Posted by STI8U
The GT2835 IMO is not too small for my setup (remember, 2123cc not 2.5L)...385WHP as shown in the above dyno plot is more than enough for me, I'd be happy with 370WHP, given I'm currently making almost 300WHP on the stock turbo.

I've plotted on a GT2871R compressor map (closest thing to a GT2835) and the turbo can hold 1.6bar to redline no problems...the extra 129cc over the stock 1994cc will help make the turbo a little less laggy.

I'm not after a drag car, I'm after a daily driver that does some casual track work...so a balance between torque and power is required...

Hence why I favour the 264/264 cams...I'm worried 272/264 cams will make the car a bit laggy...
You have an 8k redline, why not use it? Cams are going to shift your curve to the right, no matter how you look it it. So in essence, they are going to make the car laggier. However, I see you with the ability to exceed whatever you're going to be able to get out of that turbo and still satisfy your goals, which is why I questioned the choice. I ran a Garrett T28 on my 1.8T Audi A4 and it spooled it decently, so I felt I posed a good question, and you answered with a good response, so I hope your turbo choice yeilds you excellent power with great response for a DD and occasional track day!

Also remember that Dynojet numbers are inflated/read higher than everything else. The Greddy T518Z is an 18G with TD05 wheel and 8cm^2 exhaust housing, which has potential for great power on your setup with good spool. Since you do have that 8k redline, an extra few hundred rpm before your curve shoots up is fine. GT30R guys can spool up pre 5k on this motor not stroked, and have 3k of big power to boot. Think of how a better mated turbo for your bigger than stock displacement and 8k redline would perform, I bet a lot of guys on here would kill to have that, myself included.
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Old 06-11-2006, 01:44 AM   #11
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272's, that still isnt that radical of a camshaft. i have 2 friends that runs 280's on their DD's
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Old 06-11-2006, 02:25 AM   #12
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you'd be fine with the 272/264 combo. it's a good comprimise... your setup sounds sick, bet it'll be a sweet road car. enjoy that motor, it's a jewel.
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Old 06-11-2006, 03:00 AM   #13
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Cool, thanks for the opinions - my tuner told me everyone in the US would say go 272/264 I want decent torque from no higher than 4000RPM onwards, looking at the dyno graph on HKS 264 cams, I'm guessing that still will happen with 272/264 cams (although Kelford 264 cams > HKS 264 cams)

With 272/264, do you go need to upgrade your valves and/or valve springs? I've been told the valve springs should be upgraded to stop them binding but I'm not sure whether this is just an upsell...

Yeah I realize about Dynojets but at least the clutch power looks pretty accurate at 430PS (only +40PS over horsepower at hubs)...

Last edited by STI8U; 06-11-2006 at 03:09 AM.
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Old 06-11-2006, 07:56 AM   #14
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Go with the Jun 272 cams with the valve springs and titanium retainers, the more hardcore tuners would also tell you to lose the avcs and get an adjustable cam sprocket. My uncle did this and gained more than 40whp.
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Old 06-16-2006, 12:03 PM   #15
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^^ Yea but who sells an adj. cam gear for subarus? I bet it's expensive.
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Old 06-16-2006, 12:09 PM   #16
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Quote:
Originally Posted by jtanoyo1
Go with the Jun 272 cams with the valve springs and titanium retainers, the more hardcore tuners would also tell you to lose the avcs and get an adjustable cam sprocket. My uncle did this and gained more than 40whp.
Why would the most hardcore tuners tell you to lose AVCS? I don't understand how you can say that at ALL. Think about people who go with a Hydra, most have some serious setups, and Hydra can control AVCS. Why you ask? Because AVCS is an asset, tuned correctly it can improve spool and low-end power. Did your uncle do this on a Subaru or a different car? I've never heard of it before.
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Old 06-16-2006, 12:26 PM   #17
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Quote:
Originally Posted by jtanoyo1
Go with the Jun 272 cams with the valve springs and titanium retainers, the more hardcore tuners would also tell you to lose the avcs and get an adjustable cam sprocket. My uncle did this and gained more than 40whp.
AVCS is an on the fly adjustable cam gear. Why would you get rid of it?
I can see adding adjustable exhaust gears.

TMS
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Old 06-16-2006, 12:50 PM   #18
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Some people lose avcs because the cost of avcs cams can get up there. Other than that, I don't know why anyone would do it. I think Phil at Element is a pretty serious tuner, and he's advised me to keep the avcs if possible.

I honestly don't know a bunch of guys running upgraded avcs cams. I would chirp at bboy. He's been tuning his AVCS cams on his Hydra for a few months.
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Old 06-16-2006, 02:14 PM   #19
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The reason why people ditch AVCS is two reasons. 1. Jun auto does not make AVCS compatible cams. 2. The AVCS system can only advance the cam timing. You cant retard timing. This means you cant tune for top end power. For an engine that revs out very high, adjustability can mean alot of power up top.

Several companies make the adjustable wheels. Jun is one.

Clark
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Old 06-16-2006, 02:54 PM   #20
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Clark,

I don't know too much about tuning but I thought advancing timing as you got higher into the RPMs helped to make more power? Also, why ditch AVCS because one company doesn't make cams for it?
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Old 06-16-2006, 03:24 PM   #21
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EJ motors will make more top end power with the cams at 0. Any advance kills top end power. The is alot of power to be had with retarding the Exhaust cams. Without running adjustable cam gears its real hard to make power up at 7k+

Clark
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Old 06-16-2006, 03:32 PM   #22
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Thanks for the info Clark, it's not what I expected from what I've been reading on here. Is advancing timing at lower RPMs beneficial?
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Old 06-16-2006, 03:39 PM   #23
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We are talking about intake cam timing here.. Yes. Advancing the intake cam helps bottom end and midrange power. The problem is that its not a simple adjustment. When you adjust this you change the dynamic compression of the motor. Now you must retun the IG timing and the AFR. What we can do is retard the exhaust cam which would help alot. Some of the newer Subaru engines do have avcs on the exhaust cam as well. In an ideal world we could go back and forth over the centerline of the cam. For now the only way is to use adjustable gears.

Clark
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Old 06-16-2006, 03:51 PM   #24
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So who else but Jun makes adj. cam gears?
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Old 06-16-2006, 03:53 PM   #25
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OBX, they are cheap, they look good, and havent heard any negatives.
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