I currently have a GSR with JR and 6lb boost pulley. I am wanting to upgrade to 9-10 lbs.

Correct me if im wrong, but I know the stock bore is 81mm but i am unsure of which thickness head gaskets would be safe to use. I am also concerned about lowering the CR. will this lower my bottom end, or will the greater boost compensate for the loss.

Please give me some feedback. Thanks

 

bro i wouldn't run more than 6lbs unless its tuned

if you use a thicker head gasket you'll lower your compression

for example my friends gsr motor is a 10.1 compression resleeved and with still be able to run 15 lbs or boost safely...

call jackson racing for any Q's you have man

 

You don't really want to drop the compression for a supercharger. It will only make you lose the horsepower you're trying to gain with the bigger pulley.

The JRSC is blowing a lot of hot air at 9psi, so if you wanna go that route, you will need to get a good tuning computer and get it tuned at the same time.

The motor itself will be fine.

 

which comp are you familiar with. I have heard of the Hondata which is popular, however there are diff models with tons of additional features. do you know which models/features would benifit me for my setup? Thanks for the info

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LudeyKrus &raquo;</TD></TR><TR><TD CLASS="quote">You don't really want to drop the compression for a supercharger. It will only make you lose the horsepower you're trying to gain with the bigger pulley. </TD></TR></TABLE>

Anytime you have forced induction you want lower compression. More compression = more heat = less dense inlet charge = less power. Its a fine balancing act of what to have or not. yes you can have a 12:1 CR with 15psi, but your asking for disaster.

To be safe, drop the CR, get the ECU figured out, then boost.

Rich

 

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

Anytime you have forced induction you want lower compression. More compression = more heat = less dense inlet charge = less power. Its a fine balancing act of what to have or not. yes you can have a 12:1 CR with 15psi, but your asking for disaster.

To be safe, drop the CR, get the ECU figured out, then boost.

Rich</TD></TR></TABLE>

This is not true. I'm not going to give a very long drawn out explanation of dynamic compression ratios and cylinder pressures, but here's the jist of it.

When your motor is actually spinning, you want a good cylinder pressure at TDC. Dropping compression will drop this a bit. You can add a good bit of boost before it gets maxed out. Once you look at everything, though, you will realize that you don't need to drop compression most of the time. It only gives you a bit more room for error when tuning.

Droppin compression when not necessary will only make it so that you need to push more boost through the motor to make the same power.

 

Ludey, thanks for the explaination..... However, I still am not sure of your advise. Are you saying to run the additional boost with the stock gasket and keep the CR the same as long as I use some sort of management system.

Or are you saying... change the gasket to lower the CR just a little to be "more safe" and add a management system before upping the boost.

Again, can you reccomend a management system and what features I would need?

Also, do you know how far Flowery Branch is from the Woodstock/Marietta area?

 

As stated dynamic effective compression ratio is what needs to be taken into consideration.. On a 10:1 static ratio engine such as a gs-r 6psi will yield about 14:1 dynamic. At 10 psi you are running a dynamic ratio of about 16.5:1. So at 10 psi with a static ratio of about 8.5:1 you will be running about the same 14:1. Performance will more than likely be very close to the same in both applications. As for JR, the more you boost the higher the intake temperature is. Biggest pronlem with thier small displacement superchargers. I would go for a hondata headgasket and a water injection system for that and boost a safe 10 psi on a 10:1 stock motor. And run way better than the 10psi on a thicker head gasket. It will cost more but be way better.
These numbers are not necessarily acurate but are pretty close and give you an idea of what you are looking at. I'm not going to go into all that hooplah also. But this little tidbit should help. Just like LudeyKrus said dropping compression when its not necessary only means you have to boost more to yield the same results. Some applications it is necaserry to do though.