328 compression euro/us

Haven't come across anything myself in the F literature that contradicts them being 9.2:1 for US and 9.8:1 for standard (euro), and have seen those specs given in enough places to have some confidence in them:

euro 328 OM 376/86: standard = 9.8:1

euro 328 OM 513/88: standard = 9.8:1

Suisse 328 OM 434/87: CH = 9.2:1

US 328 OM 396/85 = none given

US 328 OM 535/88 = none given

308QV/328 WSM 550/89 page B44: standard = 9.8:1, USA = 9.2:1, , CH version = 9.2:1

Technical Specifications/Publication List/Recall Campaign/Service Bulletin Index 328GTB/328GTS page B5 in Tech Specs: US version = 9.2:1

and the 328 SPC shows the US and CH versions use the same piston, and it is different from the standard piston (so that fits the pattern).

Can you identify the "conflicting info"?

 

I can't recall ever coming across lift data for 328 cams (so don't really know if it's the same or different for each version, but would guess that it's the same), and the cam event data in those same prior references has more errors/confusion, but, using the 308QV/328 WSM as "correct", gives that on the US version the exhaust cam was retarded by 4 deg compared to the standard version.

Also, the wiring schematics in the OMs for the ignitions imply that the US and standard version use different ignition maps (but I have no specifics on the actual differences).

 

The delta on the compression ratio had nothing to do with NOx emission levels. The reason lower compression was used in US versions is because of the lower octane rating in US fuel relative to Europe at the time.

 

Bluemels book has quite a bit of incorrect information particularly on US cars. It is too bad it is being used as the bible. I accept his production figures because no better source is available as yet. Reading his book is what made me decide to work on my own. A better source of V8 information needs to be generated.


328s all had the same cams. There were differences in FI systems, compression, cam timing and as stated the Microplexs were designed with many advance curves for different markets. The end result was from the best to the lowest output motors not a great deal of difference. Less than the claimed HP figures would suggest.

 

In regards to the convex wheels and non ABS,Australian delivered later cars had this set up.I think the main difference between the two cars is the weight though.If Bluemels book is considered correct,it states that the difference between the two version makes the US cars heavier by 350 lbs for the GTB and 357 lbs for the GTS cars

 

No 328 in any market had hydraulic clutches.

That myth got started because the factory had a misprint in the parts book. Table 34 of the October 88 parts book shows the brake hydraulic system and the bottom of the page says "Clutch Hydraulic System".

That is what happens when an author gets his knowledge from other books rather than venturing out into the world and getting information first hand. It also happens when he is so cluless about cars he cannot tell a picture of a brake system from a picture of a clutch system.

 

Mike, you're absolutely right. To run on lower octane gasoline you can either retard the timing, or, lower the compression ratio. Ferrari chose to lower the compression ratio somewhat. I believe the advance curves were the same for euro v. US spec but others here may know better than I.

There's a lot of chemistry and physics to the science of addressing "knock" or pre-detonation - it's not just compression ratio. It also has to do with chamber design and avoidance of concentrated hot spots among other things. So, there's no universal rules about what the limts are but generally, to get anywhere near 10:1 you need very good cooling of the chamber, good flow design w/o hot spots (often caused by smaller radius corners or lack of proximity to cooling passages), higher octane gas, and moderate advance curves. Knock sensors generally just retard timing and that's certainly helpful on a spot basis but the net of it is less hp/tq when you need/want it. Twin plugs is helpful and there are some basic twin plug designs that do just fine with 10:1 on US gas.

 

Are these CR's real or academical?

Look at the 308 2-valve engines, and how far the piston is at TDC from the deck. Does the same apply to the 328?

 

And then there are 11:1 motors that do just fine on US gas like the 355 and 360. Their detonation sensors almost never come in to play and then only in rather unusual situations. Good chamber design, good fuel and spark control are the keys.

 

??

They are calculated just like every other motor. Pretty much covers real and academic.

What difference does it make?

 

It can make quite a difference.

In the cae of the 2V engines, I don't believe that the 'unswept' part of the cylinder is accounted for in the equasion, which would then leave the actual CR a good bit lower than the calculated CR.
This is just a gut feel, I'd have to do actual measurements, but I don't have any (unskimmed) cylinder heads and pistons lying around.

 

I think your gut feel needs a serious tune up. Its actually more than a feeling.