DIY Turbo Discussion greddy on a 1.8? homebrew kit?
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Low boost built motor?

 
Old 06-05-2008, 05:42 PM
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Default Low boost built motor?

Instead of boosting the **** out of my stock motor...could it be beneficial to build a 1.8 with turbo pistons and lightweight rods, have everything balanced, get some headwork done...basically make my engine more efficient (better flow, less restriction), but for a low boost application (6-8psi)? What engine upgrades are there or what can I do internally to my engine to make or free up more horsepower? I feel a stock miata engine is underpowered, what makes this engine that way? What restrictions are there that can be removed?
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Old 06-05-2008, 05:52 PM
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with a low boost motor, I'd raise the compression and do major headwork.
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Old 06-05-2008, 05:54 PM
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Originally Posted by thirdgen View Post
I feel a stock miata engine is underpowered, what makes this engine that way?


Low displacement, non-honda heads, too much gay.

If you remove the gay you should realize a 33.3% power increase.
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Old 06-05-2008, 06:03 PM
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Low boost sounds cool. But if you are spending the money to build your motor. And spending the BANK on a turbo.
Why not have crazy power? Either way; High compression low boost or low compression high boost. It still takes away from the dependability. That is compared to stock.

Now if you have parts available cheap, or setting in the floor doing nothing. And you need a plan to make it work, that is different story. Just my .02 cents
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Old 06-05-2008, 06:17 PM
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Originally Posted by Braineack View Post
with a low boost motor, I'd raise the compression and do major headwork.
What kind of headwork can be done on the 99 motor for more power?
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Old 06-05-2008, 06:19 PM
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everything....
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Old 06-05-2008, 06:21 PM
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Originally Posted by Braineack View Post
everything....
I don't know anything about that kind of work. Care to elaborate or shall I google? =P

Like valve job and port + polish?
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Old 06-05-2008, 06:22 PM
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cams, valves, springs, porting, deshrouding, gears, blending, etc etc etc.
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Old 06-05-2008, 06:22 PM
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Start with what you have money for, and then define your specific goals based on that budget.
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Old 06-05-2008, 06:24 PM
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Originally Posted by compy View Post
What kind of headwork can be done on the 99 motor for more power?
Hehe...

Alot is the answer. If you're unfamiliar search the forum for some threads on this subject.

On my 99 head I did some MAJOR unshrouding (not your typical unshrouding job), undercut valves, blended the bowls into the chambers and throat, reduced the short side radius, pollished the combustion chambers, removed any casting marks from the intake ports, and pollished the exhaust ports. When finished the car got so much more air that it was slower when I floored it because the stock ECU wasn't adding near enough fuel. Car would buck, backfire, and fall on its face. After Megasquirt it was ALOT quicker than stock.
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Old 06-05-2008, 06:27 PM
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Will do. Sounds like doing that kind of work can make a big difference. I'm sure it is not very cheap either. Sounds like a combination of engine work along with a turbo could make some nice power.
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Old 06-05-2008, 06:34 PM
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If you are at low boost why would you bother doing anything to the motor, it just doesn't make sense. Spend the money on some proper managing and turn up the boost, once you want even more power, then build the motor and you have a beast, so start saving for a 6 speed etc. You get the point.
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Old 06-05-2008, 07:12 PM
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I built a motor to make 250whp with a ton of headroom because I want to put 100k miles on it, drive 4-hours to the racetrack, drive it for 2 hours on the track and crush gt3rs's, then know I'm going to make it home.

I probably would have been ok on a stock motor and a gt2560, but I had the money and wanted to do it once and be done with it.
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Old 06-05-2008, 07:15 PM
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i built a motor to make 250rwhp without any headroom. i boosted my stock 1.6L.
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Old 06-05-2008, 07:28 PM
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Originally Posted by Braineack View Post
i built a motor to make 250rwhp without any headroom. I boosted my stock 1.6L.
1. How many miles do you get out of motors boosted like that?
2. Do you have alot of oil seal problems?
3. Why can't the pony speak?......................Cause he is a little horse!....
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Old 06-05-2008, 07:33 PM
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So back to my question...What can be done to the stock motor to make power, besides high comp pistons. I want details. A stock 1.8 has what, 140hp at the flywheel? I want like 175, on a low compression motor, stock computer...is this possible?
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Old 06-05-2008, 07:36 PM
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there are plenty +200rwhp 1.6Ls. it's not difficult.

I boosted my last motor for 2 years, almost to the day...maybe 10k. It had horrible oil consumption from day one. unknown mileage JDM import. It bit the dust when i started boosted +15psi and running aggressive spark on a +90 day.

this new motor was $200 score. engine overheated, sat around for years at a shop. simply slapped a head on the block and went boosting again. I have 0 oil consumption and make around 250rwhp at 12-13psi.
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Old 06-05-2008, 07:37 PM
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stock computer, low compression pistons? why?!

the pistons alone will kill your power output, especially on the stock ecu.....you're silly.
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Old 06-05-2008, 07:39 PM
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I have a built engine, and I was thinking about a low boost setup, ben and I were discussing it the other day.

My engine:

ETD Rods
10:1 compression
99 head w/big valves
MSPNP..etc...
a bunch of other small tweaks...

We were thinking a large-ish turbo... perhaps a GT28RS at 4-6 PSI, hell possibly non intercooled. Off boost response should be great with the higher compression and better head, and would probably make <200 hp. For all-out efficency I could run the S4 tubular manifold and maybee the BEGI intake, but that would be taking it too far I think.

throw on a WI system and then you can crank up the boost for the track.
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Old 06-05-2008, 07:43 PM
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Originally Posted by thirdgen View Post
So back to my question...What can be done to the stock motor to make power, besides high comp pistons. I want details. A stock 1.8 has what, 140hp at the flywheel? I want like 175, on a low compression motor, stock computer...is this possible?
Lowering compression and keeping a stock computer wont make it easy to get much more power. I dont know if that could be done.
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