What's the main difference with things like pistons and rods?

From my tiny knowledge;
Rods:- You generally seem to get H-Beam and I-Beam type. The I-Beam seem to be rated for higher power. If I was to buy some H-Beam ones, is it worth getting the most expensive ones, or are cheaper ones up to the job? i.e. Eagle rods seem to be cheaper than Brian Crower, but are the Eagle rods worse?

Pistons:- Again, they seem to be the same, but differently priced. Wiseco seem to be cheaper than JE, and the most expensive are CP. Is it worth paying more for CP pistons over Wiseco pistons, or are they generally the same, and can handle the same power?

Compression Ratio's:
What's the difference between the ratio's, and what's the point in changing it from standard? I think standard on a newage is 8:5:1. What does this mean? And is it worth changing it? How do you change it if your rebuilding? Just thicker head gaskets?


Cheers

 

bump

 

 

Simply, you just need to have a realistic "goal" and spec accordingly, over priced components would have to justify their cost IMHO.

A higher compression ratio will give better off boost performance, but then the components needs to be strong enough to take the boost levels desired.

C.R. can be adjusted by using head gaskets of differing thickness, but the pistons are the major factor along with headwork...

All vastly over simplified of course.

dunx

 

The most suitable compression ratio has more to do with the type of fuel you are going to be running (therefore it's resistance to detonation) and to a lesser extent the amount of boost you want to run. If you are only going to be running race fuel, then you could afford to increase the compression ratio and the engine would make more power at a higher CR than it would on a lower CR. However if you try run a high compression engine on 97RON, you will probably find that you are not able to run the boost or timing that you want and will therefore actually be down on power (due to being knock limited).

I believe stock CR is 8.0:1 to 8.3:1 on most of the turbocharged EJ series engines. It would be worthwhile retaining a CR at around this level if the car is a road car.

The easiet way to change the CR of an engine being built is to use pistons which are manufactured for this purpose. If you have a look around pistons options on the RCM website, you'll get the idea.

PS: C/R on normally aspirated engines tend to be much higher due to not running boost.

 

Thanks a lot for the explainations guys.

For me then, I would need to stick to the standard C/R as I would be running a road car on V-Power.


As for components used, I understand you would spec for the build, but are CP pistons proven to be better than Wiseco pistons? Due to the price differences?
Same for H-Beam rods, due to the cost does it mean Brian Crower are the best out of the H-Beam ones?

 

Chris, try posting the piston and rod questions on 22b.

 

There are a few threads on NASIOC that explain the differences between the components, sorry dont have any links on my work computer.