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Forum namePerformance/Engine
Topic subjectALL MOTOR 12.5 Compression?
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i5&topic_id=22493
22493, ALL MOTOR 12.5 Compression?
Posted by 98Talon, May-07-02 06:19 AM
Okay... I've had my talon for a month or so now... it's time to start upgrading. Turboing seems to be the way to go.... but I don't want to follow that trend. What all would I need to do to put 12.5 to 1 compression pistons in my car. What else needs to be involved. I will have the basics done, CAI, Exhaust, UDP, and I assume some sort of ignition retard system (any suggestions). Has anyone done this on here, or will anyone give me a pricing estimate. Also... do I need to build my bottom end for this?

Adam
22494, RE: ALL MOTOR 12.5 Compression?
Posted by wakebord99, May-07-02 12:50 PM
Anything you do multiplies the HP you would gain from the higher compression, but basically, i believe you could leave everything
else stock, and just change the compression.. More fuel wouldn't hurt.



97' Eclipse RS (kinda)

Present mods:
HRC stage III turbo kit (12 psi street, 25 psi track) / HKS 2 1/2" cat back exhaust w/burnt cat / 16" wheels w/Yokohomo tires (215/40) / 420A engine w/ tooled crank, billet crower rods, and 8.5:1 JE pistons / Head ported and polished, 3 angled valve job
Power-stop brakes w/axis pads / Ebachi Pro lowering kit (1.8") / MSD DIS-2 ignition system w/turbo retard

Near Future:
Stand-alone fuel system / 550cc injectors, and fuel rail / TEC III fuel/ecu system / 17” Hart racing wheels / KYB AGX struts, w/ upgraded anti sway bars / Rear brake conversion (front to rear, Brembo in front)

Jay-
wakbrd99@aol.com
22495, RE: ALL MOTOR 12.5 Compression?
Posted by jkoston, May-07-02 04:48 PM
So if you decided to go all motor, and got 12.5 compression, would you be able to pass smog?

I think i've decided to go this way, because I don't want to deal with the smog hassle of turbo right now.
22496, RE: ALL MOTOR 12.5 Compression?
Posted by mcgyvr, May-08-02 12:35 AM
you will at least have to run the high octane gas all the time, but I would also put and aftermarket ignition with some thing to retard timing so you dont go kaboom. and to go to 12.5.1 compression you have to build the bottom end with the 12.5.1 pistons/ rings and rods at least. I would also do the top end with the lifters/rockers from the pt cruiser and get a nice bumpstick to compliment all that then wait for the new ecu to be out and run higher rev limit and you would have a nice little all motor car. then you can get a quad throttle body setup and run nice times in the 1320
22497, RE: ALL MOTOR 12.5 Compression?
Posted by babybeclipse, May-08-02 06:26 AM
You don't need to run race gas on 12.5.1 compression. But never go under 92 or 93 Octain. Their are plenty of high compression all motor monster neon on the street running on pump gas.

How many miles does you motor have? If you have low mileage I wouldn't bother with the bottom end. Build the rest of the motor/car first then once your over 100k I would upgrade.
22498, RE: ALL MOTOR 12.5 Compression?
Posted by wakebord99, May-08-02 01:07 PM
>I wouldn't bother with the bottom end.

Are you telling him he should do Ignition, fuel, exaust, etc before touching the engine.. and not telling him he should throw
12:5:1 compression pistons in an otherwise stock bottom end.

I don't think that engine would last 5,000 miles.




97' Eclipse RS (kinda)

Present mods:
HRC stage III turbo kit (12 psi street, 25 psi track) / HKS 2 1/2" cat back exhaust w/burnt cat / 16" wheels w/Yokohomo tires (215/40) / 420A engine w/ tooled crank, billet crower rods, and 8.5:1 JE pistons / Head ported and polished, 3 angled valve job
Power-stop brakes w/axis pads / Ebachi Pro lowering kit (1.8") / MSD DIS-2 ignition system w/turbo retard

Near Future:
Stand-alone fuel system / 550cc injectors, and fuel rail / TEC III fuel/ecu system / 17” Hart racing wheels / KYB AGX struts, w/ upgraded anti sway bars / Rear brake conversion (front to rear, Brembo in front)

Jay-
wakbrd99@aol.com
22499, RE: ALL MOTOR 12.5 Compression?
Posted by 98Talon, May-08-02 03:05 PM
My motor has 88,000 miles on it as it sits in my driveway right now... damn straight it's getting a built bottom end. What am I looking at pricing wise for EVERYTHING?

adam
22500, RE: ALL MOTOR 12.5 Compression?
Posted by HadesOmega, May-08-02 08:30 PM
Oh so turbos are trendy eh? It's simply the cheapest most effective way to creat more horsepower in your car. Don't bring NOS into this also cuz it's not reliable. I thought like that b4 OoOooO I want a built all motor eclipse cuz there ain't too many of them out there. But I came to my senses and realized all motor cost too much and performance isn't worth it. It's ok if you got money I guess...

If there were a supercharger would you get it, I have yet to see a supercharged eclipse in person...
22501, RE: ALL MOTOR 12.5 Compression?
Posted by babybeclipse, May-08-02 11:14 PM
Hell, that would probably cost more than ALL-MOTOR! If someone made a kit, I would go for it. But, custom everything. I don't think so.

I'm not out to make any speed records I just want to see how well this car can do All-Motor.
22502, RE: ALL MOTOR 12.5 Compression?
Posted by 98Talon, May-09-02 12:38 AM
I don't expect to be smoking turboed 420A's with this car.... I'll have a new one in a year at which point this one is going to become most likely my girlfriends car. I just want something different than a turbo, my next car (RX7) will be turbo... so I want this one normally aspirated. Anyway... I have nothing against turbocharging, my last car was turbo (89 porsche 944 turbo) and I ADORED it. I just thought it'd be fun to try and pull 225-240 horsepower out of an all motor 420A and retain drivability, that's all.

Adam
22503, RE: ALL MOTOR 12.5 Compression?
Posted by babybeclipse, May-09-02 05:55 AM
Ditto :)

Who has actually done (12.5 compression) mod so far?
22504, RE: ALL MOTOR 12.5 Compression?
Posted by Michael_97RS, May-09-02 06:19 AM
12.5:1 is fully streetable in a 420A. There are plenty of Neons running 12.5:1 compression. It's the route I plan on going. The higher compression will adds to the power all your bolts on will produce compaired to on stock compression. Adding roughly 3-4% for each C.R. point raised.

Ideally to make the most power with 12.5:1 you would want all the bolt ons, fully ported and polished intake manifold along with a bored TB. Full exhaust; header, high flow cat and cat-back. a beafier upper end would be good. Upgrade tp PT Cruiser lifters and rockers. I would recommend some work with cams, wether it be cam gears so you can increase overlap on the stock grinds or going with aftermarket cams would really help. A good grind of cams can produce a nice lope at idle that could cause the car to want to die at low speed lift throttle situations.

At the more axtreme end, where I am headed, eventually... You want head work, P&P, and gasket matched. upgraded valves and valve springs, wilder cams, stand alone fuel management, and a new intake manifold/dual, even quad TB set up. To take all motor to the end will be expensive, and for the power produced most likely not as efficient as slapping on a stage 2 turbo. But the power bands is different and motor characteristics are different, so I would hope to be pulling somethign comparable to a stage 2 turbo at the end. I would expect low 14, and be damn happy with 13's.

Una salus victus.
It's not about being invincible, it's about being ready; for anything.



Michael J. Kulaga
e-mail: Michael_97RS@2gntDSM.zzn.com aol IM: MJKulga
http://highlander.dsmpower.com/

All motor in the making.

Injen CAI, 55mm TB, Hooker 4-1 Stepped Header, GS-T Muffler, AFX UDP, S-AFC, 8.5mm Magnecor Wires, Crane Fireball HI-6DI2, SS Clutch Line, NRG Susp. Motor Mount Ins., FU/RU/RL STBs, TSW Blade 17x7.5, Bridgestone Potenza RE730 215/45ZR-17. Front KVR Cross-Drilled Rotors & Carbon Fiber Pads

To Be Installed: P&P Intake Manifold 1/2, P&P Milled Head, Rear Disc Brakes, Rear KVR Cross Drilled Rotors & Carbon Fiber Kevlar Pads, SS Brake Lines