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Yes, that makes sense, but the high lift might actually reduce low-end torque, I think, especially on the exhausts. You could experiment with mixing ratios. A lower lift ratio on the exhausts can increase port velocity and aid the intake more on the overlap. Even on the intakes, the high lift reduces intake charge velocity, so you don't get as much cylinder filling at low piston speeds. Luckily it's easy to play with the rockers once the engine is installed. Maybe you can find the combo that gives you what you want by experimenting and roadtesting.

The higher lift ratios also alter the effective valve opening duration somewhat. I ran mockup tests on several cams with 1.1 and 1.25 rockers, and generally the higher ratio makes the valve stay above .050" a bit longer on each end, but the results weren't as consistent as I expected them to be. Best to put a degree wheel on and a dial indicator on a valve and see what the different ratios actually do with the cam you want to use.

It's funny how the 2253 has a shorter advertised but longer .050" duration than the 2254. That means the ramps are a bit quicker. I din't snap to that when I was ordering my cam, or I might have tried that one instead.

Did you say you're using T4 rockers? Do they fit the T1 shafts? I'm curious because some T4's had a 1.3 rocker.

So you have 8.3 DCR? What altitude are you at? Does it need premium octane?

FYI Webcam will custom grind any spec you want if you guys want to really play.

I am at 3000 feet elevation. I am currently using premium in my 2.1 litre with the W110. I just feel better using it. The DCR in my current engine is 7.6 but I will target a DCR of about 8.0 in my 2.4.

I assumed I had T4 rockers because they apparently came from a 2 litre air cooled bus engine from the years 80 to 83. Maybe the rockers in the T4 sedans had the extra lift. I did check the lift at the valves when I rebuilt the engine and everything checked out. They do fit the T1 shaft.

I will consider your idea about mixing ratios The port velocity thing makes sense.

wellington:
thanks for the info. I will check it out.

Hi guys Sorry to interupt

I have actually posted a Q about using T4 rockers it WBX and I read you mentioned you got T4 rockers Coz I beliefe out of 2 sets T4 you can make them work on the WBX Is it possible to give me some info PLS are the ratio better of the T4 rockers than the WBX

Thanks
Pierre

milesahead, you know you lose 0.2 DCR per 1000' ASL, so you would deduct 0.6 from your calculated DCR for your normal altitude of 3000'. That means your real DCR is about 7.0, which means you would probably not have detonation even on regular octane, or midgrade at the worst (provided that's sold in Canada). Lacking a knock sensor, though, high-test does provide that margin of safety, and these days the price difference is relatively unimportant (when you're paying $3, who cares about saving a dime anymore?).

I'm knocking off a whole 1.0 for 5000', which is lower than I commonly drive. I live at 6400'.