4G63 Powerband

[93AWDTalon1]

I've been looking at different dyno sheets lately. And there is something I have noticed the 4g63 motor looks to have much flater powerbands than other 2.0L engines like honda's power is always very peaky. And even when they both rev to 9k the dsm powerband is smoother. I was wondering what it is about our motors that make them have these flat powerbands?

 

[thegreatms]

are both the motors you are looking at turbo? because a stock turbo motor will often have a flatter hp curve, because the turbo raise the hp in the mid range. (With a larger turbo this goes out the door)

 

[psychlow]

I've been looking at different dyno sheets lately. And there is something I have noticed the 4g63 motor looks to have much flater powerbands than other 2.0L engines like honda's power is always very peaky. And even when they both rev to 9k the dsm powerband is smoother. I was wondering what it is about our motors that make them have these flat powerbands?

What dyno charts were you looking at?

Engine design can have some to do with this, but for the most part it's all in the parts you put on the engine. For example, if you have huge cams and a huge turbo, it's going to be much more 'peaky' than a stock-cammed, medium sized-turbo car. It also depends on how much max boost pressure the engine is pushing and how much turbo lag you're getting - if you're running 30PSI but can only get 20PSI by 4500RPM, that'll make the power curve peak as well. If you're running a 16G at 22PSI and can fully spool it by 3600RPM, that'll flatten it out.

The engine design can matter slightly - for example, the WRX boxer engine naturally has a flatter torque curve than a 4G63 for the most part (which is why Suby uses it for a car that gets its roots from rally racing.) But that could always be altered when changing items like intake manifolds, turbos, cams, head porting, exhaust, etc.

 

[pickens]

Engine design (RR ratios, port profiles, cam timing, etc.) play a HUGE part in shaping the torque curve. 4G63 have flat POWER bands because the torque falls off quite rapidly which is really not what you want. The torque curve is what you want to be flat which is directly related to the volumetric efficiency of the motor across the RPM band.

 

[xbeck]

i have a PT SCM61 and HKS 272 combo, and my dyno graph doesn't flatten out at all. i still have the stock rev limit, but make my top power right before it cuts out.