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DIY Turbo Discussion greddy on a 1.8? homebrew kit?

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Old 09-11-2011, 03:02 PM   #21
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Originally Posted by 1slowna View Post
Or the 323gtx pistons which are 7.8:1
Heh it would be like the old school 911s.. 30 lb/ft torque until 5k rpm then from there on you cant hold it straight.
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Old 09-11-2011, 10:04 PM   #22
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Heh it would be like the old school 911s.. 30 lb/ft torque until 5k rpm then from there on you cant hold it straight.
my b6t was like that.... i milled the head so i was at a whopping 7.9:1 on 19psi... goes from gutless to burning out with no happy medium
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Old 09-12-2011, 02:52 AM   #23
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Til I **** on you and you finally stepped it up to a 1.8
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Old 09-12-2011, 03:37 AM   #24
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Some say lower compression helps with durability. I feel like it just robs torque and less torque increases durability.
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Old 09-12-2011, 04:12 AM   #25
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Originally Posted by fastivab6tg25mr View Post
my b6t was like that.... i milled the head so i was at a whopping 7.9:1 on 19psi... goes from gutless to burning out with no happy medium
Wouldn't milling the head raise compression?
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Old 09-12-2011, 06:47 PM   #26
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Originally Posted by 1slowna View Post
Some say lower compression helps with durability. I feel like it just robs torque and less torque increases durability.
I feel like we need a time machine so the new members can go back 18 months and relive the forum discussions where it was proven that dropping compression to 8.5:1 increases torque across the powerband by allowing significantly more timing advance.

Low compression = big timing advance = big power and low EGTs = durable
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Old 09-12-2011, 06:53 PM   #27
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*assuming pump gas.
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Old 09-12-2011, 07:12 PM   #28
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Mmmm I love learning. You guys are the ****.
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Old 09-13-2011, 10:37 PM   #29
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adding my vented block picture

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Pretty sure there's not meant to be a hole here...-254165_10150280187665505_635150504_9501294_1678824_n.jpg  
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Old 09-13-2011, 10:59 PM   #30
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Quote:
Originally Posted by 1slowna View Post
I feel like it just robs torque and less torque increases durability.
And what is the connection between torque and hp?

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Originally Posted by tasty danish View Post
Wouldn't milling the head raise compression?
No milling the head lowers it, over boring the pistons on the other hand raises it.
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Old 09-13-2011, 11:07 PM   #31
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I'm not good at this game, what EXACTLY are we looking at right there?
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a vagina
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Old 09-14-2011, 12:02 AM   #32
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Milling the head reduces the size of the combustion chamber and increases the compression ratio. What makes anyone think otherwise? It is how people have increased compression ratios since before Fords were flat head v8s. I've done it to increase the compression ratio on several engines I have built over the years.

What is going on here? Am I accidentally on m.net or something?
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Old 09-14-2011, 12:03 AM   #33
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adding my vented block picture

Now THAT'S A HOLE! Holy crap! I'm surprised it didn't bend the frame! Or kill some kittens!
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Old 09-14-2011, 12:18 AM   #34
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Quote:
Originally Posted by sixshooter View Post
Milling the head reduces the size of the combustion chamber and increases the compression ratio. What makes anyone think otherwise?

For the ease of the example.

Piston has 9cc and 1cc space in the head.

So it takes 10ccs (piston + space in head) and squeezes them into 1cc. 10:1

Same piston bigger head.

9cc piston 2cc head.

So thats 11cc and squeezed into a 2cc head. Whats 11 squeezed into a 2cc space?


5.5:1

5.5:1 is LOWER compression ratio than 10:1.


Overboring pistons on the other hand RISES compression.

Over bore the same piston to 10cc so thats 11cc total (overbored piston + regular head) squeezed into 1cc space.

11:1 ratio.


Err wait you mean shave off the head...
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Old 09-14-2011, 12:27 AM   #35
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Quote:
Originally Posted by triple88a View Post
And what is the connection between torque and hp?


No milling the head lowers it, over boring the pistons on the other hand raises it.
Yes just like you said.
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Old 09-14-2011, 12:39 AM   #36
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Quote:
Originally Posted by triple88a View Post
Err wait you mean shave off the head...
Yes, also known by the rest of the world as milling the head.

Typically you grind in the chambers to cc the head. Taking out more than a couple cc's is considered rather extreme and thus the amount it changes the compression is not a large factor.

Your piston argument is moot because you aren't going to shove the same piston in a larger hole, and the requisite new piston will have its own design and thus effective compression ratio.

Or you could just be trolling in which case I'm a ******* moron for taking the bait.
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Old 09-14-2011, 05:05 AM   #37
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Now THAT'S A HOLE! Holy crap! I'm surprised it didn't bend the frame! Or kill some kittens!
I've always been curious if anyone here has shot a rod through a body panel, hood, etc. It adds insult to injury and I would be at least 15 kinds of mad.
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Old 09-14-2011, 06:34 AM   #38
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Savington, how much experience have you had playing with compression on E85 now?

Im in full agreement over the 8.5:1 = timing=torque, but one wonders if with e85 the new 8.5:1 becomes 10:1....11:1?

Dann
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Old 09-14-2011, 10:48 AM   #39
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Quote:
Originally Posted by Savington View Post
I feel like we need a time machine so the new members can go back 18 months and relive the forum discussions where it was proven that dropping compression to 8.5:1 increases torque across the powerband by allowing significantly more timing advance.

Low compression = big timing advance = big power and low EGTs = durable
I feel like I need a time machine to catch up on all the threads and actual discussions like this... not being around for almost 3 years = WAY behind on the currently known info = lots of catching up to do.

any particular threads of interest?
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Old 09-14-2011, 10:56 AM   #40
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Just blew mine up. I was putting down around 280. You're lucky you got that out of it!
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