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Compression Ratio??

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Old 04-08-2013, 11:16 PM
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Fluidplay
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Doug - don't read in to my "Not a bad Thing" comment. It wasn't a celebration by any means of woohoo, look what i got!! Just surprised that with the current configuration could support much more than i thought, that's all.

..and yes, the turbo has the smaller #8 housing. This turbo hit boost at 3800 with a good tune.
Old 04-08-2013, 11:57 PM
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Paulyy
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my $0.02..

325 rwhp is a good reliable amount of power.

If it was up to me, i'd go for the 8.1:1 CR and you probably wont need to go more then 15 psi of boost, probably less.

I wouldn't be stressing over it.
Old 04-09-2013, 12:40 AM
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All that work your doing I'd save some $$ and get rods with the build.
Old 04-09-2013, 12:49 AM
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blown 944
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I'll second the rods comment.

IMO for your stated goal, I would use the higher compression.

If it is track only ,the current turbo might work either way.

If you're thinking about big HP later, I'd go with the lower compression. You will have a much larger safety margin
Old 04-09-2013, 01:45 AM
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333pg333
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+3. Dennis with your power goals those 7's are too low. To make use of that sort of compression you'd want to be boosting to 25-30psi which entails more mods to the motor than you're listing.
Old 04-09-2013, 08:12 AM
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67King
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Originally Posted by 333pg333
+3. Dennis with your power goals those 7's are too low. To make use of that sort of compression you'd want to be boosting to 25-30psi which entails more mods to the motor than you're listing.
That's pretty much it in a nutshell.

In other news........I would revisit my approach if I were you. I'd never develop a goal around a turbo that I have, I'd pick a turbo based off of a goal that I have. Opinions vary on this, but mine is to always go with the smaller turbo that will support your goals.

Also, side note, but Wossner now makes a standard 944 piston, they are no longer all custom jobs. So if you stick with a stock compression ratio, it'll be a lot less expensive than a custom one.
Old 04-09-2013, 08:45 AM
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333pg333
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Sorry for being forgetful Dennis but what size motor are you going for again?
Old 04-09-2013, 11:43 AM
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Fluidplay
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Originally Posted by 333pg333
Sorry for being forgetful Dennis but what size motor are you going for again?
Patrick - 2.5 , pistons 101
Old 04-09-2013, 05:22 PM
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333pg333
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I've got a nice little GT3076 .63 sitting in the garage not doing anything. Was a great turbo for the 2.5L motor. It's not bolt on but it's there if you'd like it. I'll do you a good price.
Old 04-09-2013, 10:42 PM
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Fluidplay
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Patrick, appreciate the offer...I'm going to take a breath and weigh my options. I've been pushing to get this thing back together for this season since funds and parts become available. I missed the entire season last year going through a bunch of BS and was really looking forward to getting back in car....with my foot on the gas....the pistons pumping...and feeling the kick of boost it will happen....DAMN IT!!
Old 04-09-2013, 11:02 PM
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333pg333
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Know the feeling X 1000!!! It's there if you want it. :-)
Old 04-10-2013, 03:18 PM
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Have located a new set of pistons with 8:1 CR...the build continues.
Old 04-10-2013, 05:09 PM
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Sounds better.
Old 04-11-2013, 12:13 AM
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yeah, I really want to thank everyone for their input positive or negatively...it all helps in putting things into perspective...I'm looking forward to getting it all back together and enjoying why I bought the car in the first place...having fun!!
Old 04-12-2013, 03:10 PM
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Patrick, appreciate the offer...I'm going to take a breath and weigh my options. I've been pushing to get this thing back together for this season since funds and parts become available. I missed the entire season last year going through a bunch of BS and was really looking forward to getting back in car....with my foot on the gas....the pistons pumping...and feeling the kick of boost it will happen....DAMN IT!!

Hmmm!!

I know a little about this build as the person helping you is a very good friend of mine. I wouldn't exactly call it ""BS"" Dennis. From what I have been told you haven't exactly gotten poor over this build and received alot of trick parts for ????

As for the CR number, you are picking fly sh'' out of pepper. Have you discussed this with who's helping you build this engine?? If you havent I would do that first. He knows his stuff!! Asking here and not listening to who's helping you is an insult in my book.

BTW, I'm assuning the CR has been measured while building the engine. I would bet there isn't an engine on this forum that is actually the stated CR number. Stock engines are never 8. More like 7.5 when measured.



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