What is it that makes the JDM cars rev higher than our UK cars. Back in the day we used to use cams to get our old Ford motors to rev higher than standard but i see cams are not so big in the Scooby tuning circles (well not average tuning anyway).

Do the JDM cars have much different cams to ours?

 

the cams are different, but also as crank is better then the engine is safer at higher rpm, the rev limit is set in the ecu, presume you could raise it on a uk engine but as the crank is weaker/not nitrided or crossdrilled wouldn't last as long, but this is my own opinion from tuning other cars.

 

You would think if my car can take 400bhp on the standard crank it would be able to rev a bit higher without damaging anything. There is just sooooo much to learn about these cars.

 

It's not down to the crank, as many of the model years share the same crank for WRX and STi models. - I've run a stock GC8 crank (not nitrided or cross drilled, but in a built motor) to over 8500rpm

The heads are different. - Classic UK turbo and WRX (inc Newage) 1997> have overbucket shims.
STi models 1997>2000 have underbucket shims and 2001> Sti has shimless buckets, and both have stronger valvesprings than the WRX equivalent.

 

Just put it down to far eastern madness and go have a cuppa.

Essentially JDM cars are set up and equiped to be rev monsters but we Europeans prefer mid range torque and quick response to the throttle. Plus all of our cars are de-equiped in case the Yen goes pear shaped or the price of oil goes up.

J.

 

Almost everything rotating in the JDM cars is lighter and/or stonger then the EU/UK counterpart.
Also the heads are different, as to actually make useable power higher up int he rev range.

 

And also the difference in rod/stroke ratio and oversquare engine design of the JDM 2.0 as compared to the UK 2.5.

 

Indeed a factor.
I was basing my statement on 2 litre cars tbh, but the ratio of the 2.5 is not helping that engine in the high rev department.

 

so whats the different between the newage jdm and uk engines?

 

jdm newage still runs 2.0 even till current model hatch is still twinscroll

 

Correct, the UK/EU get the 2.5, the JDM market keeps the higher revving 2.0.
Also, comparing the JDM 2.0 to our old 2.0, the JDM ones had,amongs other things different valves, cams,springs, pistons and (sometimes) rods and cilinderblock, so basically
they are 2 diffent engines and almost the only thing they had in common was the displacement, the rest is like apples and oranges.

 

so like our newage engines are good for 450bhp.. jdm ones are good for more?

 

Probably the same powerwise, but the JDM engine imho would take this kind of abuse for longer.
However don't expect any stock engine to support a 450bhp for a very long time.
Maybe a trailer queen, or a dragcar used once every 2 weeks, but as a daily driver (and using the power daily) 450bhp is to much for any stock Subaru engine IMHO.

 

MY01/02 engines are similar to the MY02-MY05 UK engines, the MY03 onwards twin scroll units are very different.

Tony

 

Not true!

My Spec C's built 2.5 engine rev'd as well as the previous JDM 2ltr engine did. Running OE crank but forged rods and pistons.... same stroke as OE 2.5 build. Engine rev'd freely to the 8200rpm rev limit I had with appropriately uprated/spec'd valvetrain.