JDM VR4 RS 4g63T Compression

[dsmayhem]

First off let me say that I have searched and searched and not found a definitive answer to this question. Secondly I don't really want to debate about JDM engines in general.

I am picking up a JDM 4G63T from a Galant VR4 RS with a big16g and yellow top injectors this week. Obviously before I buy and or drop this engine in I want to do a compression test. I have heard conflicting reports about this engines compression. Some say it has the same compression as a USDM 6bolt and others have said it has an 8.5:1. Now those are both going to yield quite different compression results. Does anyone have a definitive answer as to what I should be expecting compression wise?

While we are at it I found this in my search:

JDM VR4 RS 4g63T
Higher lift cams
lightened flywheel
3inch intake Elbow
lightened UDP
510cc injectors (yellow)
big 16g turbo
cyclone intake manifold
8.5:1 compression
6bolt block
1g big rods/crank
better clutch

Can anyone verify any of that other than the 510cc injectors and the 16g?

 

[NOSNUSE]

8.5 to 1 is the compression. As far as the block, rods and crank what year is the motor? It should come with a cyclone intake(dump it in favor of a 1g intake), the rest of that I am not to sure about but the flywheel, clutch, UDP, 3" intake elbow, but I would imagine it is the same as the standard V-R4. i know the they were rated with more horsepower but that is because of the turbo. Hope this helps you out a bit, later.

 

[dsmayhem]

Thank you for the info! I just want to make sure that when I do a compression test I know if it’s in spec or not. I was just worried because 8.5:1 would be giving me different numbers that what I was expecting. On the good side that’s almost like having 2g pistons on 1g rods so that’s hott.

 

[00 Agent]

Hey dsmayhem:

Can you post your results so we can confirm if they are indeed 8.5:1? I would like to know this for sure as well.

 

[dsmayhem]

Will do. I should be picking it up early next week so I will post then with the info.

 

[NOSNUSE]

I found this on a website about the galant vr4 rs and this is what they had to say,"One great thing with the Galant VR4 RS is its compatibility with the later model Lancer. When Mitsubishi developed the Lancer Evolution they borrowed the VR4 RS engine and driveline." Well I guess maybe I was wrong the compression ratio is 8.7 to 1 and not 8.5 to 1 so there is a slight difference sorry about that. Oh and the power output was 240hp.

 

[dsmayhem]

That would still be pretty damn cool. Yeah I really need to get that thing.

I did manage to find some more info on it...

http://f2.autospeed.com/cms/A_1853/article.html?popularArticle

Best of the VR4s
An extra-hot Evo and Evo RS version of the VR4 was manufactured for the Japanese market from about 1990 onward. We're told the Evo makes 162kW (220ps) and the Evo RS pushes a healthy 176kW (240ps) - the extra grunt coming from a bigger turbo and intercooler, an upgraded cooling system and oil cooler. A revised close-ratio gearbox was also fitted.

http://arabia.autospeed.com/cms/A_1913/article.html

http://www.turboprojects.com/galant.htm

Just info on the car really.Still nothing on compression though.

 

[NOSNUSE]

Well according to everything I have found on the motor you are buying the compression should be 8.7 to 1 because that is the stock compression on the EVO 2-3, but in the Evo 4 and up the compression went to 8.8 to 1. I am 99% sure that it is 8.7 to 1.

 

[boostedinaz]

Well DMayhem and I picked up his motor today and got somepics. Here they are.


http://members.cox.net/dmayhem/JDM/JDM 003.jpg

http://members.cox.net/dmayhem/JDM/JDM 005.jpg

http://members.cox.net/dmayhem/JDM/JDM 008.jpg

Michael


PS. We will get compression numbers once we get it hooked up to a starter.

 

[LordZed]

I'm sorry to bring this back... two years later...but did you ever get the compression numbers for this engine? I ask because I'm now running an RS motor and want to know what your's checked out at.
I sent dsmayhem a PM but it's been a week and no reply. Are the fact's about the RS's higher compression in fact true? It's a bit hard to find a lot of info on these engines.
Thanks!

 

[Mo-Bo0st]

Send a message to boostedinaz....he will be more likely to respond to you.

 

[GVR4592]

The compression in the RS is identical to the U.S. 1g cars, 7.8:1

 

[LordZed]

The compression in the RS is identical to the U.S. 1g cars, 7.8:1

I was speaking of his compression check more so than the actual ratio. But thanks! I've heard the ratio was identical as well, but was wondering what his checked out at as a used motor to compare it to mine. Just for poops and giggles.