I was looking at the parts catalog for the crossfire and came across a couple of intresting things. It lists the na compression at 10:1 and the SC compression at 9:1 . And I have also noticed that some of you SRT6 guys running larger crank pulleys are running about 22psi of boost. That seems extremely high for a car that has 9:1 compression ratio to start with.
So, what I was wondering is if any of you SRT guys have done a compression check and if so what were the results.
I'm going to do a compression check on my na as soon as i get the gauge from my brother.

The whole purpose is to verify the acual compression ratio on the two engines. I have a feeling that they are going to be identical. The short block part # 05114264aa has both egx(na) and egz(sc) listed as its application. Which means the limited and srt have the same short block. And I know they have the same heads so where is the difference in compression coming from?

 

According to the on-line parts manuals (Chrysler and MB) The 3.2L engine shares the same block, heads and valves - but that's about it - part numbers are different for the pistons - rods, camshafts, crankshaft...

The cylinder bore may be the same but I would guess that the piston domes, piston stroke, valves etc.. provide the difference in compression ratios.

Even if you could just "bolt on" a factory SC on the NA Crossfire - you won't have the same engine.

 

the NA will read higher compression due to higher CR obliviously, but the srt6 will give a lower reading on your gauge, yetthe cylinder pressure durring high load is way higher than the NA due to the higher atmospheric pressure being fed to it when the SC clutch is activated.

what's the point of this thread?

 

One thing you guys are missing is that when you order the short block it comes with the crank, rods, and pistons assembled at the factory. Its probably just a typo or error that it lists the short block for both applications. But , it could be that the bottom end is identical in both motors. The difference between the compression ratios could be a thicker head gasket. I'm sure I'll find out soon.

I'm just trying to find out as much info as possible before I start tearing my motor down. If its pistons I need to change or the crank and rods etc.... I will be going for an 8:1 compression ratio.

I've read so many threads where the members on this forum post negative replies about how this won't work, get a SRT, etc.... ( I'm not implying that any post so far have been negative). If you are one of those people please don't reply to my post. I couldn't care less about my warranty, gas mileage, driveability, and whatever other quips you have about not modifying the xfire. And no, I'm not here to sell anything to anyone. Any information I gather I will gladly share with any of you.

 

I don't trust the part numbers. If you change the stroke and not the bore you won't have 3.2 liters of displacement. I don't want the same motor. I want a better motor.

 

Hey Montana Crossfire, are you ever gonna leave the circus and get off the crack?

 

Are you hearing yourself?
the answer is NO!

 

If you are building a motor for any kind of boost the compression must be lowered to withhold the extra pressure (for higher boost applications.....lesser amts can be run on a stock engine). if it is true that the part #'s for the block are the same and the pistons/rods/etc. are different that should sound completely correct. And 9:1 compression sounds just fine for boost. I built my honda......STOCK BLOCK with SRP pistons, eagle Hbeam rods. comp dropped to 9:1 and running 21 psi of boost (can run more w/ different MAP sensor), putting 300whp on a SINGLE cam. Weight w/ me in it. 2150lbs....VERY FUN!

 

Engine Block Part Numbers Are Different For N/a And Supercharged Engines The Price Is A Whole Lot Different Block For A S/c 10,670.00 N/a 3,670.00 So Yes They Are In Two Very Different Categories.....

 

Hi I had asked about a comparision between engines and the specs for both are listed in the post.
https://www.crossfireforum.org/forum...ad.php?t=22544

 

The most random post ever.

 

After reading the above mentioned post I found that the compression reads 100 psi for the Limited and SRT6. If this was true, than they would have identical compression ratios.