Is their difference between the two engines cams and if so dose anyone have the specs for them (lift, duration, ect.).

If there is a difference, what is the part numbers for the 350 cams and has anyone with a 250 done a swap over.

I’ve done a lot of Cam swaps on just about every car I have owned and I was wondering if this would be a easy “Hot Cam” set up for the 250.

Thanks, Neil

 

I doubt anyone has tried it, but I would be so very surprised if it would work well (or even at all). I would expect that the differences would be way too significant.

 

I don’t see why it wouldn’t work, their is really not that much of a difference between the two engines. From what I have read the 350 is just a bored and stroked version of the 250s engine and I doubt the 350 is making the extra power it has just out of the extra displacement. I haven’t been able to find any info on the cams but I am willing to bet that they are "bigger", and it should be a simple swap out and a computer reprogram to adjust for valve timing.

 

There are more differences than just displacement. The fuel injection is also completely different. The 350 has a combination of direct injection and port injection while the 250 just has port injection. I don't know how that would change the cam profiles, but I suspect that would be a significant change to the heads. The computer reprogram would also be a HUGE biach since nobody has been able to hack Toyota's encryption.

 

250 only has direct injection not port!

 

Wow! That's a shocker!

 

Well thats good to know about the fuel system and computer, but what about the specs of the cams them selvs? If the 350 cams wont fit what about haveing a custom grinde made? There are alot of cam companys out there that will make anything you want if you give them the numbers. Just an idea.

 

Here's everything Toyota will tell you about the 2GR and 4GR:



As you can see, there isn't much to work with here. It's very unlikely stuffing different cams in the engine will result in much. It might be more valuable to swap both cams and cam drive components since VVTi is going to attempt to thwart any change you make because the ECM is keenly aware when you've changed cams.

Should you choose this path, don't assume it will be all good. In all likelihood, it will not be good at all.

 

The ecu won't know the cam ramp, lift, phase or duration has been affected from any change. The only measurement it has to go off is the corellation of the Cam and Crank sensor pulses. The Cam is controlled via VVT control and it uses a PID control loop comparison between target and actual.

If your cam does in fact increase flow the MAF will deliver the increased flow signal to the ECU and it will make its necessary adjustments to compensate for fuel trim and ignition timing. Since the stock timing has been optimized for stock, switching out the cam and changing the MAF signal could very well also change the timing so you could either loose power or possible have excessive timing and develop knock. The OEM knock sensors should compensate and safe gaurd to prevent damage but case remains that power loss in lower RPMs is more than likely gonna happen.

That senario about would only be true as long as the ecu doesn't detect any misfires from increased overlap. If it does it will revert to significantly reduced timing to reduce chance of engine damage and would send one in the path of remorse.

After seeing the ports on the 4GR engines I would hardly think the cams would be any larger than the ones that fit into the 2GR engines.

-Joe

 

What would you like to bet the cams are identical and only the sprockets are different to allow the phasing to be different (note the duration of both engines is the same, but the lobe centers are 3 degrees different on the intake and 7 degrees on the exhaust.)