Lower Compression


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mazdarx7

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Oct 15, 2009
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To lower compression of a 2000 Model DC2 Integra type R, Can i just replace the type r pistons with a Integra VTIR ?

They are both B18C engines, and from what i understand, all B18C have 81 * 87.2 Bore and Stroke, making the 1,797 replacement..

Can someone please let me know if it will fit, and will it significantly lower compression for small T28 turbo + 6 PSI boost max ? ( I’m thinking of compression 10 flat )
 
ya man those pistons will work...it will take your compression from 11.1 to about 10.3 if you are stuck on using OEM pistons rather than some nice forged beauties you might look into some pr4 pistons from a b18b non vtec...those wuld put you at about 9.3:1...because from 11.1 to 10.3 doesnt seem like enough difference to make it worth the trouble!!! just my $0.2 tho
 
compression isnt a bad thing with turbo's, just like all motor, more compression means more power. but it requires precise tuning and a higher octane fuel to prevent detonation..so thats why most ppl go lower compression!!
 
If your going to go through the trouble of changing pistons do it right and add some forged pistons, but if all your after is 6psi from a small turbo you can leave your compression as is as long as you have high enough octane fuel and a good tuner. You can also run a thicker headgasket.
 
Man, this place is really great, thanks for the replies, Got some follow up questions if youse have time .. Thanks

1 . (you might look into some pr4 pistons from a b18b non vtec...those wuld put you at about 9.3:1) How sure are youse that these pistons will fit? I was thinking that the con rods wont fit, ??

2 . anyone know if its possible to buy a decompression plate for a ITR ? whats better ? the D plate or changing pistons ?

3 . With the small turbo (T28) is it necessary to change the Injectors ? Or the Type R injectors are good enough ?

4 . ( as long as you have high enough octane fuel and a good tuner. ) For tuning, can the stock ECU be tuned? or definitely needs after market ECU ( Im thinking of Microtech ECU ) ,,, What % octane are we talking bout here ? i always fill up 98% , is that good enough ? or needs octane boost added ?

Thanks heaps
 
pretty sure the pr4 pistons will fit tho sum1 else might verify that for me....blinx? ur using pr4's??? right!
i would imagine slightly bigger injectors would be bennificial...probly at least some prelude 290cc inj. or some rc310's...again someone who is more involved in turbos might have more input on that....as far as tuning i would recomend hondata but thats just my opinion.... and octane all depends on what you do decide to put in there but if you stay at stock compression and boost i would talk to whover you are having tune it and see what octane they can tune for
 
Yea i have pr4 pistons in a b16 block but i still suggest real forged pistons to anybody who is doing this. Larger injectors of course, i'd say at least 450cc, but talk to your local tuner for that.

As far as a decompression plate, are you referring to a thicker head gasket? Many companies make them.
 
blinx9900 said:
Yea i have pr4 pistons in a b16 block but i still suggest real forged pistons to anybody who is doing this. Larger injectors of course, i'd say at least 450cc, but talk to your local tuner for that.

As far as a decompression plate, are you referring to a thicker head gasket? Many companies make them.
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the best website for forged pistons i could find is Race Engineering, Inc

best kit i can see for what i want to do is,

G5 PISTON:B18-81.0mm/9.8:1+RINGS (KIT) -- what do youse think?

Just so i know, when these pistons are installed, or any that will lower the comp
to 9.something , Would i actually loose power, assuming its on 150 KW at flywheel , How low do youse think it might go? ( Im thinkin max - 10 KW at the flywheel )

I took your advice and checked out Hondata ECU's i cant figure out at all what is for my car, any suggestions, on the hondata web, it was saying something about OBD1 and s100 and s200 and s300 . i have no idea what it means, that why im thinking the microtech ECU, simple and they map it for you..

Need you thoughts again. Thanks
 
mazdarx7 said:
the best website for forged pistons i could find is Race Engineering, Inc

best kit i can see for what i want to do is,

G5 PISTON:B18-81.0mm/9.8:1+RINGS (KIT) -- what do youse think?

Just so i know, when these pistons are installed, or any that will lower the comp
to 9.something , Would i actually loose power, assuming its on 150 KW at flywheel , How low do youse think it might go? ( Im thinkin max - 10 KW at the flywheel )

I took your advice and checked out Hondata ECU's i cant figure out at all what is for my car, any suggestions, on the hondata web, it was saying something about OBD1 and s100 and s200 and s300 . i have no idea what it means, that why im thinking the microtech ECU, simple and they map it for you..

Need you thoughts again. Thanks
Click to expand...

You'll need Hondata s300. Is your car a JDM one? if yes you can buy the Hondata S300J.

Your car since it is a dc2 integra type r, you have a OBD2A ecu engine harness. This means you'll need tu buy a OBD2A to OBD1 conversion harness + the Hondata ecu system :))
 
mazdarx7 said:
the best website for forged pistons i could find is Race Engineering, Inc

best kit i can see for what i want to do is,

G5 PISTON:B18-81.0mm/9.8:1+RINGS (KIT) -- what do youse think?

Just so i know, when these pistons are installed, or any that will lower the comp
to 9.something , Would i actually loose power, assuming its on 150 KW at flywheel , How low do youse think it might go? ( Im thinkin max - 10 KW at the flywheel )

I took your advice and checked out Hondata ECU's i cant figure out at all what is for my car, any suggestions, on the hondata web, it was saying something about OBD1 and s100 and s200 and s300 . i have no idea what it means, that why im thinking the microtech ECU, simple and they map it for you..

Need you thoughts again. Thanks
Click to expand...

For engine management get one that you and your tuner are comfortable with, if people in your area tune microtech then get that :nice:

Lowering compression does lower power but your going to have a turbo so don't worry about that, if you can find pistons that will get you around 9.2-9.6 that would be great, 9.8 is a bit high for some tuners BUT if your tuner feels comfortable tuning a 9.8 CR turbo setup then go for it!
 
blinx9900 said:
For engine management get one that you and your tuner are comfortable with, if people in your area tune microtech then get that :nice:

Lowering compression does lower power but your going to have a turbo so don't worry about that, if you can find pistons that will get you around 9.2-9.6 that would be great, 9.8 is a bit high for some tuners BUT if your tuner feels comfortable tuning a 9.8 CR turbo setup then go for it!
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Ok .. Just to get started, what i think has to be done, to turbo it and not have problems, until i change all the other parts slowly is this..

ITR turbo kit

T04E TURBO CHARGER
T3 Flange to Manifold
5 Bolt Downpipe Flange
3" Inlet Diameter & 2" Outlet Diameter

UNIVERSAL TURBO INTERCOOLER
27x7x2.5
2.5" outlet and inlet
150 to 130 Degree Temperature Drop

INTERCOOLER PIPING KIT

MANIFOLD FOR B-SERIES ENGINE
Made of High Grade Stainless Steel
Uses T3 Turbos and 35MM/38MM Wastegate Flanges
All nuts and bolts included
Direct Bolt on

38MM WASTEGATE
Utilized 35MM/38MM Flanges
V-Band top allows for quick changing of springs
Designed to release gas efficiently
Better Control of Turbo

VOLTAGE STABILIZER KIT
Increase Horse Power And Improve Audio Sound Quality
Improve Ignition Flow
Strengthen Starting Power

BOV BLOW-OFF VALVE
FLANGE PIPE
FUEL PRESSURE REGULATOR
TURBO BOOST CONTROLLER
OIL CATCH TANK
TURBO TIMMER
OIL DRAIN KIT
OIL FEED KIT

( for the time being, Clutch and injectors stock )

Pistons + conrods + Piston Rings to lower to 9.2 or 9.6 compression ..

Microtech ECU + Dyno tune..

Im thinking that is all thats required to run on 6 PSI .. ( before i was going to get a T28, is the T04E too big on 6 PSI or okay ? )

Please let me know if there is anything i have missed out that is definitly necessary..Or just your thoughts and ideas.. Thanks heaps

( What i mean by other parts is : changing the engine mounts, CV joints, strengthen first & second gear in gear box, Heavy duty clutch, change head gasket, etc... )
 
What brand of turbo, manifold, wastegate, blow off valve will you using>
 
blinx9900 said:
What brand of turbo, manifold, wastegate, blow off valve will you using>
Click to expand...

Turbosmart Australia Pty Ltd - Blow Off Valves

Turbosmart Ultra-Gate - 38mm Wastegate

Garrett T3/T04E Ball Bearing Turbo

Greddy Manifold

So what you think, as a whole?

Thanks
 
mazdarx7 said:
Turbosmart Australia Pty Ltd - Blow Off Valves

Turbosmart Ultra-Gate - 38mm Wastegate

Garrett T3/T04E Ball Bearing Turbo

Greddy Manifold

So what you think, as a whole?

Thanks
Click to expand...

Most Greddy manifolds are T28 flanged, how are you planning to fit the t3/t04e on there? Any reason you have chosen the t3/t04e? Have you looked at Garrett's GT series of turbo's? they are much better.
 
im actually getting the turbo & manifold & dump pipe from a AUS performance company that deals with garrett & Greddy etc... they just gave me a good deal on the lot,, they had the turbo in stock so gave me a really good deal on that..( was from a old project, never completed )

But what do you think about the idea as a whole ? do you think with the good tune, pistons it should run all good on 6 PSI and driving the car good ?
 
you should be able to run a lot more than 6psi with forged pistons and a good tune, more like 16psi...
 
Im abit worried about the pistons, is there any internal engine differance between the B18C7 ( Australian Model ) and B18C5 ( US Model ) ?

as in, if i get a B18C5 forged piston, at 81 mm bore and it says it will lower compression to 9.1 ... Is it possible that they might not fit on my B18C7 ?
 
All B series vtec are 81mm bore, but b18c5 pistons are high compression pistons, they will not lower your compression. Why don't you get a set of forged pistons?
 
blinx9900 said:
All B series vtec are 81mm bore, but b18c5 pistons are high compression pistons, they will not lower your compression. Why don't you get a set of forged pistons?
Click to expand...

nah , i am getting forged pistons , but there from america and i assumed all pistons sold there are for b18c5 engines..

it actually only says B18C for the piston .. so its probaly all good..
 
Your wrong sir. USDM b18c engine is actually B18c1 aka GSR engine AKA UKDM B18c4 engine. You can buy pistons for any motor in America, not just b18c5.
 
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