As the topics says,
Which one is better? why?
I gotta buy a new motor, and before I do I'll like to see which one is better.
-I know the jdm gsr has more HP and higher compression, but would it work good with the super charger?

Thanks,

 

the jdm gsr has 180 hp and its compression is higher and is also more expensiver then the usdm but they are almost identical, so i say you save the money and buy the usdm motor

 

USDM GSR 10 1 compression
JDM 10 6 compression

now USDM GSR motors can have high mileage ,(depends what year motor you get )
the JDM motors mostly are going to have less than 40 k and most good engine importers do compression tests to there motors ,
i want to get another b18c USDM and get it reffed , i heard jdm motors can pass with a few things
the thing i like about the JDM motors you take the head off for porting and upgraded valvesprings and u slap a mugen or spoon headgasket and u are running almost 11 1 comprssion without slapping pistons on with the jdm b18c

 

first off, there is no such thing as a JDM GSR motor, they don't make GSR's in japan, they do however have b18c1 which cames from models such as the sir, si, sir-g, etc.

the JDM motor is actually CHEAPER than USDM motors since usdm motors are more rare and there's a hugh supply or jdm motors, usdm motors have the ability to be legal if you get the BAR sticker. the JDM motor however is higher compression therefore more power.

 

dumb question probably...but does the jdm b18c motor pass all the reguations and stuff req. by us law or what?

 

just smog issues.. I'm sure there are ways around it. there are plenty of people that have JDM motors in their daily drivers

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by VTECorona &raquo;</TD></TR><TR><TD CLASS="quote">just smog issues.. I'm sure there are ways around it. there are plenty of people that have JDM motors in their daily drivers</TD></TR></TABLE>

yeah, but do they live in California?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MugenGTR &raquo;</TD></TR><TR><TD CLASS="quote">first off, there is no such thing as a JDM GSR motor, they don't make GSR's in japan, they do however have b18c1 which cames from models such as the sir, si, sir-g, etc.</TD></TR></TABLE>

Second off, there's no such thing as a JDM B18C1. The JDM motors don't have number suffixes. The Si-VTEC/ SiR/ SiR-G has B18C.

 

to answer your question simply: go with the lower compression usdm w/supercharger.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Gatecrasher19AF &raquo;</TD></TR><TR><TD CLASS="quote">

Second off, there's no such thing as a JDM B18C1. The JDM motors don't have number suffixes. The Si-VTEC/ SiR/ SiR-G has B18C. </TD></TR></TABLE>

good call.

 

what i dont understand if the jdm gsr motor is 10.8 what pistons is it running? p73?which is an itr piston.
i havent seen any jdm supplier sell jdm gsr pistons unless they are using the itr ones in the jdm gsr. beats me.

Carlo

 

They are JDM GSR pistons. Reason nobody sells them is because there's no point in upping compression .5. Your better off just getting the JDM ITR pistons. Not positive on part number, I think its still P-72 maybe with a different extension on the end. Either way its not really important. If your boosting get the USDM GSR motor because it has slightly lower compression. If your swapping pistons, get which ever motor is cheaper and more readily available.

 

USDM is legal, JDM is usually not smog legal...but u can always get someone who doesnt care as long as your smog numbers are good

 

I'm trying to get better numbers at the track,
I'm not really concern about the smog inspection thing...

 

Higher Compression=Better track times. You don't have to have lower compression to run boost of any kind. Like all those turbo idiots who drop their compression just because everyone else does. It is just a myth. The only reason you should be lowering your compression is because it is easier to tune and you can run more boost, but it really just evens out cause a built motor can handle more boost anyway. I wouldn't go w/the JDM just because it won't pass emmissions plus you live in Cali where they're strict as hell. I say go with whichever motor is cheaper. And the only motor in Japan is the B18c, no #'s. Just sir/ sir-g/ etc. How many psi is the supercharger running?

 

i say just get the motor that is in better coindition(milage) and is cheaper. either way i say its your call.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Havokmkr &raquo;</TD></TR><TR><TD CLASS="quote">Higher Compression=Better track times. You don't have to have lower compression to run boost of any kind. Like all those turbo idiots who drop their compression just because everyone else does. It is just a myth. The only reason you should be lowering your compression is because it is easier to tune and you can run more boost, but it really just evens out cause a built motor can handle more boost anyway. I wouldn't go w/the JDM just because it won't pass emmissions plus you live in Cali where they're strict as hell. I say go with whichever motor is cheaper. And the only motor in Japan is the B18c, no #'s. Just sir/ sir-g/ etc. How many psi is the supercharger running?</TD></TR></TABLE>

thank you, I hate seeing people who say lower compression is better. The higher the compression, the more hp per psi of boost you get. Thats why GS-R's make the same power at 7psi that LS's do at higher psi.

-Andrew

 

I would go with whichever is cheaper as well, with a slight preference towards the JDM motor due to the higher compression.

10.6:1 is an awesome CR for a JRSC'd setup if tuned properly. If you plan on doing it right and dont plan on cutting too many corners, go for the JDM motor, as you'll see more power with the charger down the road. High compression and JRSCs go well together, as you want the most power per PSI since your maximum boost level is limited due to the blowers innefficiency at high RPMs. If the car is tuned properly, raising compression is a good way to make power. I PMd you back as well

 

jdm motors are cheaper th en usdm. sinc eits alot easier to make it smog legal.. i say get a jdm motor get a thicker head gasket then supercharge it....you can still make the jdm motor pass smog in california ive made many cars pass smog with jdm motors.. just have to comply with the smog requirments...

 

JDM.
thats they way i went on my old car. make sure you get a lsd with it too, cause they were a factory option.
i loved that motor......

 

Dont get a thicker HG...you want the compression.

 

The JDM B18C for the SiR-G's attains the same 10.6:1 CR of the USDM B18C5 b/c the combustion chamber volume is smaller and the SiR-G pistons have a piston compression height slightly lower than the P73-A0 pistons used in the B18C5 motor.

The piston code for the SiR-G B18C is P72-00.

The P72-A0 pistons are used in teh GS-R USDM B18C1 motor. Those are flat-top pistons. Zero compression height.

If anybody wants to see comparisons, we've got a set of P72-A0's and P72-00's laying around. I just have to find them.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Gatecrasher19AF &raquo;</TD></TR><TR><TD CLASS="quote">

Second off, there's no such thing as a JDM B18C1. The JDM motors don't have number suffixes. The Si-VTEC/ SiR/ SiR-G has B18C. </TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MugenGTR &raquo;</TD></TR><TR><TD CLASS="quote">first off, there is no such thing as a JDM GSR motor, they don't make GSR's in japan, they do however have b18c1 which cames from models such as the sir, si, sir-g, etc.

the JDM motor is actually CHEAPER than USDM motors since usdm motors are more rare and there's a hugh supply or jdm motors, usdm motors have the ability to be legal if you get the BAR sticker. the JDM motor however is higher compression therefore more power. </TD></TR></TABLE>

Why do you have to bust *****, you both knew what he meant.

 

But will a JDM B18C run correctly on a USDM P72 ECU. I have a JDM Si-VTEC and have been told by numerous chip/ecu sellers that chips for USDM P72s wont work in my JDM P72 as the USDM B18C1 has an extra sensor that the JDM B18C doesnt have and therefore a USDM P72 will throw a code when it doesnt get a reading from that sensor...heard EVAP sensor mentioned but i'm not 100% sure

 

If ur not concerned about smog legality then get the JDM motor.