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Old 10-19-2009, 03:22 PM   #1
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Default It's about time for my build thread

I'm building a new motor and going to upgrade a bunch of other stuff at the same time, so I figure this is a good place to put it. I'm looking for 250-275whp for a DD and occasional track car with the option to ditch my Greddy or upgrade it for 300+whp.

What I have now:
'90 Miata
megasquirt I
-fan control
-EBC valve
-idle
360cc RX-7 injectors
ETD Racing exhaust manifold
MAF delete - 2.5" intake pipe and K&N airfilter
99 5sp tranny
4.1:1 TI Torsen Diff
front racing beat swaybar
PLX wideband
Harddog Hardcore roll bar
2003 front sport big brakes and rotors
knock off rewind rims
Fuzion ZRi tires
turbo PCV
Hard top
ss clutch line
MMR motor mounts
TSIs
Toyota COPs
depower steering (quick mod method)
MOMO seats
Greddy turbo
intercooler v-mount, piping 2" hot, 2.5" cold
Tokiko shocks with racing beat springs (crappy)
2.25" straight through exhaust, resonator and hollow cat
momo steering wheel

What is in boxes:
coolant re-route (m-tuned)
gasket set
water pump
timing belt kit
ARP head studs - 218-4701
ARP main bolts - 218-5401
freeze plug 30.05mm
new 1.6 motor - disassembled
brake proportioning valve
ss drain
new greddy turbo
steering plugs
DO WI Stage 2 kit

Still to buy:
tires
head gasket - Cometic
bearing set - ACL race?
oil pump (with Boundary gears)
1mm oversized valves, springs, guides
pistons and rings
beefier clutch
550cc injectors
ss brake lines
MS-II CPU
36-1 crank trigger

On the list, but probably coming later:
6pt 3" harnesses with camlock
better BOV
radiator - mishimoto
oil relocation
oil cooler
lopro lights
downpipe
bigger exhaust
suspension - koni race, FCM tophats

Right now, I'm still undecided on pistons and I've been trying to figure out if the valves are going to require different cams to be useful or if I can run the same length stems. I'm trying to keep the car drivable with decent gas mileage, so I don't want really low compression. I think I'd like to have 9:1 with a 1mm overbore.

I want to upgrade my MS-I standalone to MS-II with sequential spark and maybe injection as well as get a trigger wheel to smooth things out and not have to worry about the crappy CAS input. Closed-loop boost and idle will be nice too.

Head will be ported and polished and possibly decked (is there a way to check that without expensive tools?) since the motor had a blown head gasket. Block will be bored and honed and crank possibly balanced. Pistons will be coated.

While I have the motor out, I'm going to completely depower my steering rack the FM way.

Pictures to come.
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Old 10-19-2009, 03:24 PM   #2
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Joe Perez will come help you if you PM him your address and phone number.
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Old 10-19-2009, 04:00 PM   #3
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CR and MPG are not mutually inclusive.
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Old 10-19-2009, 05:08 PM   #4
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Joe Perez will come help you if you PM him your address and phone number.
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Old 10-19-2009, 05:10 PM   #5
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CR and MPG are not mutually inclusive.
No, but requiring more air in the combustion chamber requires more fuel as well, so a higher CR piston will require less fuel, unless I changed the stroke as well, which I'm not.

Correct me if I'm wrong (this is me learning on my own), but changing the CR of a piston only increases or decreases the volume of the chamber. The length of the stroke is not changed, so by decreasing the volume, you increase the compression.

L*pi*r^2 is a simplified formula for the volume. I know I'm increasing r already with the overbore, so if I want to lower the effects, I would want a higher compression piston which would decrease L (well, not decrease most likely, but have less increase than a lower compression piston).

pi*r^2 won't change, so I can say that difference in the volume from the bottom of the stroke to the top is L1A-L2A (a constant - stroke length) where A is pi*r^2. The CR would then be L1/L2:1. L1 and L2 change at the same rate due to the height (yeah, it's more complicated than that, I know, but I'm simplifying) of the piston. For simplicity, I'll use numbers for a 9:1 ratio - 18 and 2. So L is 2 at the top of the stroke and L is 18 at the bottom 18/2 = 9. If we decrease the height of the piston by 1, we get 19/3 = 6.333. If we increase by 1, we get 17/1 = 17. If we plug those numbers back into the original formula, we can see how much volume that adds, which means more air and more fuel. Unless I do something like EGR or somehow substitute air with something else, I'll either increase vacuum causing loss of power or increase air causing loss of fuel.

Now, there are plenty of other variables like how much energy it takes to move a forged rod and piston vs. stock, how efficient the flow design is and probably a million other things I can't even comprehend yet, but in general is not CR a big factor for MPG and low end power for a piston?

By the way, your recent build thread was extremely helpful to me. Thanks for the info on the ebay gasket kit and such. I was curious what thickness head gasket you used, too. If I have to deck my head and/or block, should I get a thicker one to compensate?

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Joe Perez will come help you if you PM him your address and phone number.
Where does Joe live? He's the man when it comes to MS from what I've read. I wanted to talk to him about the crank trigger.

EDIT: Ah, that was a joke...ugh
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Old 10-19-2009, 05:39 PM   #6
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The difference in air volume is so utterly minute that it simply does not matter. IIRC, the CC volume is anywhere from 8cc for a high compression motor to 10cc for a low compression motor. Your 1840cc motor has a swept volume of 460cc per cylinder or so. 2%.

Higher compression motors get better mileage because they are more efficient, to the tune of 4% per point of compression, which lets you run less throttle pedal (and therefore less map pressure), which reduces the amount of fuel you have to spray.


edit: whoop, sanity check. A 10cc chamber with 460cc of swept volume would result in a 47:1 compression motor. By my math, the 9:1 motors have a chamber volume of around 57-58cc. The 8.5 guys raise that to around 60ccs.

Last edited by Savington; 10-20-2009 at 11:06 AM.
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Old 10-19-2009, 06:05 PM   #7
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The difference in air volume is so utterly minute that it simply does not matter. IIRC, the CC volume is anywhere from 8cc for a high compression motor to 10cc for a low compression motor. Your 1840cc motor has a swept volume of 460cc per cylinder or so. 2%.

Higher compression motors get better mileage because they are more efficient, to the tune of 4% per point of compression, which lets you run less throttle pedal (and therefore less map pressure), which reduces the amount of fuel you have to spray.
Thanks for the info. I know I read about fuel atomizing better under higher compression. I didn't realize the difference in volume was so small, though. I never did the calculations with real numbers.

I have a 1.6, but I'd assume the % is pretty close to the 1.8. Anyway, my original statement that higher CR is better for MPG still stands. I don't want to be like hustler and only get 22mpg. I make a lot of long trips to FL and don't want to have to stop twice to fill up every time.
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Old 10-19-2009, 06:08 PM   #8
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Your mpg will be ONLY proportional to the amount of time you spend in boost. Anything else is nearly inconsequential.
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Old 10-19-2009, 11:03 PM   #9
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Where does Joe live? He's the man when it comes to MS from what I've read. I wanted to talk to him about the crank trigger.

EDIT: Ah, that was a joke...ugh
You made me watch Billy Madison.
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Old 10-19-2009, 11:09 PM   #10
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Old 10-20-2009, 12:44 AM   #11
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in for pics of joe being held at gun point by tricker... will pay handsomely in laughs
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Old 10-20-2009, 01:38 AM   #12
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in for pics of joe being held at gun point by tricker... will pay handsomely in laughs
omg you live.
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Old 10-20-2009, 01:53 AM   #13
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I may be wrong on this but i dont think so, by increasing bore dont you actually increase compression? by forcing more air into the same combustion chamber. <edit> after further review i think i may have misunderstood what you were saying.
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Old 12-01-2009, 02:29 PM   #14
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Tell me if this sounds reasonable:

hot tank block, bore, deck, port/polish, +1mm valves, polish/balance crank - $1200

That sounds about right to me, but I know nothing about costs of that stuff.
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Old 01-18-2010, 12:50 PM   #15
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I wanted to update this thread since I have a lot of stuff and within the next month or so, I should have all the machine work done to the engine, but for some reason I don't have an edit button.

So, here's my updated list:

Motor will have new everything except maybe valve guides, Supertech +1mm valves, Supertech single springs with titanium seats, 0.040" Wiseco 9:1 pistons, rings, M-tuned rods, full boundary engineering oil pump, FM flywheel and ACT extreme clutch/pp, M-tuned coolant re-route and front water neck removed, if it works out the way I hope it'll have a 36-1 crank trigger wheel with VR sensor that all looks stock, and Integral cams later on.

Water injection will be individual runner and probably 1GPH nozzles in each, but may go down to .75GPH depending on how others do with their setups. It will be controlled by the DO at first and possibly MS2 later. I'm planning on using the washer reservoir to hold the water/meth for street and have a second tank refilling that something like what Joe Perez did, but a little different. That way I can remove the tank when just cruising around if I need the storage.

The MS2 has PWM idle with upconverter board, peak and hold injection for Evo8 550cc injectors, table switching connected to a switch in the cabin and to the float switch in the washer reservoir for failsafe (don't want to use water all the time on street, I can deal with less power and flip the switch when I want to **** someone off that their car is slow). It has baro correction incase I ever want to use it, EBC, fan control, and knocksensems.

Some other stuff includes CXRacing radiator with slim fans and shroud, ss brake lines, flush HID headlights with carbon fiber buckets, Momo Start seats with Joe O's brackets that are awesome, depowered (the FM way) steering rack, urethane bushings, Bridgestone RE-11s, and a bunch of other stuff I'll probably get later on.
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