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Old 09-13-2007, 08:21 PM   #1
rustyzipper
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Default 9:1 compression on 2.35 : Is alky/meth/water needed?

I am doing a 2.35.

But I want to run a compression ratio of 9:1, so I can run a smaller turbo and have better out of boost power. Probably some other good reasons I am not aware about.

Question: I have read in MULTIPLE 2.35 builds where they say run alky/meth/h2o for heat/det , but is it necessary?

Why? Is this a good idea?

This is a moderate build for a DD with a goal of 375-400whp pump.

Possible turbo is GT52.
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Old 09-13-2007, 09:06 PM   #2
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Quote:
Originally Posted by rustyzipper View Post
so I can run a smaller turbo ......
Possible turbo is GT52.

Tad of a contradiction?
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Old 09-13-2007, 09:16 PM   #3
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I was told that 9:1 is a bit much for 93 pump gas on my built 2.0L on the boost I'm running now(~22-23psi). So I opted to 'gasket-up'.
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Old 09-13-2007, 09:25 PM   #4
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what kind of turbos are you looking at that make the GT52 a smaller turbo?
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Old 09-13-2007, 10:21 PM   #5
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<---thats what im wondering. i thought the gt52 was huge.


~Josh~
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Old 09-13-2007, 11:34 PM   #6
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It's only big for stock location.....
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Old 09-14-2007, 08:05 AM   #7
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If I had a built 2.35, I'd run a 35R in a heartbeat. Therefore a GT52 is a bit smallish
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Old 09-14-2007, 11:01 AM   #8
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30r would be quite nice on a 2.35 for street driving and reaching your goals...through some big cams in it though as your torque curve is going to fall off badly.
I'd run alky/water/meth...whatever you want to call it
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Old 09-14-2007, 11:58 AM   #9
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Some GT52 ref threads

http://forums.nasioc.com/forums/show....php?t=1344184

http://forums.nasioc.com/forums/show....php?t=1331469

Do some researching on meth though. If I am not mistaken, it seems that there have been some issues arising because of it...that may simply be due to tuning though.
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Old 09-14-2007, 12:00 PM   #10
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Quote:
Originally Posted by cooter View Post
If I had a built 2.35, I'd run a 35R in a heartbeat. Therefore a GT52 is a bit smallish
That is what I was thinking as well.
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Old 09-14-2007, 12:28 PM   #11
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9 to 1 is not too much on pump gas. Just make sure you pick a good tuner.

Matt
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Old 09-14-2007, 03:27 PM   #12
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for the power level that you want, there are smaller turbo's than the 35R that will get you between 375-400whp. especially with an injection kit.

if your thinking about a 35R and water/alk/meth injection, then you're talking about a bit more power and possible lag.
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Old 09-14-2007, 06:03 PM   #13
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Quote:
Originally Posted by kharris4 View Post
for the power level that you want, there are smaller turbo's than the 35R that will get you between 375-400whp. especially with an injection kit.

if your thinking about a 35R and water/alk/meth injection, then you're talking about a bit more power and possible lag.

I was thinking of GT52, and injection if I needed it.



Here is what I was thinking of :

2.35 block, 9:1 compression
GT52 turbo
Injection of some kind(if needed)
pnp heads
264 cams ,springs,etc
Tranny and clutch supports mods

This will be a street driven , occasional 1/4 mile car.

I was thinking with the added strength of the 2.35 that I could bump the compression to help spool , while not limiting me on boost amount. I figure that I would be able to use the revy nature of the block to have a wide powerband and to take advantage of the GT52's flow characteristics. I would use the head work and cams so that the power wont fall off, as well as, converting it to EWG.The injection for safety and heat.

I like the GT52 as a whole turbo. And I was thinking that would be the best of both worlds. Either a 3071 or a 20G .... well here is both. I like that they state that it would have 20lbs by ~3600-3800 rpm. And that it is NOT rotated. However , this might be an over kill. But this is why I am doing this research.
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Old 09-14-2007, 07:26 PM   #14
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sounds like a pretty nice motor. are you going Axis?

myself and a few others on here are running the GT52. evryone seems to like it. there are, however, advantages to going to a 30R. you could easily move to a larger turbo without changing any pipes.

i probably would have went rotated had i not already owned pretty much everything but the turbo. i hope that this isn't taking your thread too far off track.
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Old 09-15-2007, 07:01 PM   #15
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Quote:
Originally Posted by kharris4 View Post
sounds like a pretty nice motor. are you going Axis?

myself and a few others on here are running the GT52. evryone seems to like it. there are, however, advantages to going to a 30R. you could easily move to a larger turbo without changing any pipes.

i probably would have went rotated had i not already owned pretty much everything but the turbo. i hope that this isn't taking your thread too far off track.

Axis is what I was planning. Or I have a very very good local builder that I might give it to, depends on another motor he just finished up on from another member here.

I dont think that I really would like anymore power than the GT52 can do. I know , I know , everyone says that, but I would like to finally move on to the GN project I have been wanting to do.
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Old 09-16-2007, 09:37 PM   #16
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New possible addition to the build.

I might come by a set of 2.5RS SOHC heads soon. I heard that these flow really well. Would this be a beneficial buy? Pro's vs Con's?

If I were to go with them, of course, I would go with a standalone.
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Old 09-16-2007, 09:56 PM   #17
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cons compared to EJ205 heads...if changing go to sti heads...either that or work on yours via cams or porting and valves or all of the above
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Old 09-16-2007, 11:28 PM   #18
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ok, thanks, Homemade.
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Old 09-18-2007, 06:18 PM   #19
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I run 20 psi on a EJ257 9.3 compression with the GT35R compressor. It's tuning baby!!
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Old 09-19-2007, 12:03 PM   #20
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I run 20 psi on a EJ257 9.3 compression with the GT35R compressor. It's tuning baby!!
No man, that's gambling. Pulling a ton of timing out so that you can run more boost 'will work' but it's generally not the right way to go about it. It's more of a band-aid situation. I won't even run 20psi on 8.5:1 compression most of the time with "proper" timing assuming you're talking about 93 octane.
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Old 09-19-2007, 12:22 PM   #21
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No man, that's gambling. Pulling a ton of timing out so that you can run more boost 'will work' but it's generally not the right way to go about it. It's more of a band-aid situation. I won't even run 20psi on 8.5:1 compression most of the time with "proper" timing assuming you're talking about 93 octane.
well mark if you are saying to run timing instead you might be gambling too
really there is an ideal ignition point for a given rod, crank, bore, pressure and temperature in a given cylinder...it just comes down to finding it...
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Old 09-19-2007, 12:40 PM   #22
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You run timing because spark advance is how an engine operates, you know that. I'm saying at a given octane, there's a specific boost level and timing number for an engine. Generally you'll see 8.5:1 engines in the 17-19psi range on 93 octane. Timing depends on the cylinder head, bore and other factors.

9:1 engines you'd generally see 15-17psi.

9.3 I wouldn't run any where near 20psi...if for nothing else because pump gas can vary from tank to tank. Octane is resistance to knock, backing out timing because you want to run high boost is a band aid. There are tons and tons of people that do it (a lot of 'tuners' do it), I'm just saying I would much rather be conservative and put the right amount of boost in an engine for the compression and octane I'm running.

Just like I wouldn't run 20psi on VP Import, I wouldn't run 20psi on 93 with 9.3:1. If you don't have a problem with 20psi on 9.3:1 what would you run on an SRT-4 with 8.1:1 IIRC? 26psi? 28psi? You guys are braver than I am.
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Old 09-19-2007, 02:57 PM   #23
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Quote:
Originally Posted by Mark@RealStreet View Post
...I won't even run 20psi on 8.5:1 compression most of the time with "proper" timing assuming you're talking about 93 octane.
Interesting. That's a pretty conservative street tune boost, depending on timing, fuel and hotside choice. FWIW, that is exceeded every day here, and the engines are holding up with zero problems. What ballpark timing do you look for at peak Ve and at redline?
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Old 09-19-2007, 03:16 PM   #24
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my 2.5 hybrid at 9:1 was tuned to run at 18psi on street gas(TX93oct) with an 18g
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Old 09-19-2007, 03:34 PM   #25
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Quote:
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my 2.5 hybrid at 9:1 was tuned to run at 18psi on street gas(TX93oct) with an 18g
which you do know isn't even in the sweet spot on that particular turbo.
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