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Discussion Starter · #1 ·
I'm going through the online stores looking for some replacement cams and I think I want to get a larger than stock to make a bit more power, problem is I'm not sure whats worth buying and what to pass up. I'm currently looking at an Isky racing cam with a Duration of 300/300, and a Lift of .465/.465, or a Crane Cam with a Duration of 262/272, and a Lift of .416/.430.
And even if I purchase one, i'm honestly not sure how to set the cams position and tune it. I'd like for more horsepower than torque, for highway driving.

Can anyone help me out?
 

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Well, a quick Googling brought up this thread: http://www.mr2.com/forums/threads/27427-Cam-upgrade

...although there aren't that many numbers (if any). But links to companies that supply cams for our engines. If anybody would know, it's the MR2 guys.

There was a thread just a couple weeks ago that somebody linked that had a few more companies linked.

Off the top of my head, I would check the lobe separation angle (LSA, do some research if you want to learn) on the stock cams and get something with a higher LSA. Dynamic compression ratio should go up (a very very crude way to think of it is, as LSA goes up, DCR approaches SCR with diminishing returns), which will boost high-end power especially on boosted engines, might smooth out idle, at the expense of low-end torque/power and fuel economy. You usually see this in touring cars with multiple options for the same engine: both V8s, one will have a higher LSA so you can cruise easy and have passing power at high speeds all day, vs the other option which will improve city driveability. AKA, NOT, say, a BMW 8-series comparing the V8 to the V12. A good example would be an L37 HO Northstar vs an LD8 Northstar (bringing this up because I...like Northstars. Excellent example though). The LD8 is nicer around town, works fine with a 3.11 final drive, because it is torquier but it will fall flat above a certain RPM. The L37 is paired with a 3.71 diff ratio so it can better move the 4700-lb cars it usually powers since it doesn't make as much torque at the low end. It has a wider LSA (I forget the degree difference, have it written down somewhere), which makes it smoother at idle and gives it a flatter torque curve with better power output - you start feeling it at 3500 RPM under WOT. It feels like VTEC (note that I'm talking about an engine with no VVT here).

That's just one of the things to look at if you really want to understand what's going on. Or just buy a cam that a lot of people recommend, and drop it in, make whatever adjustments they figured out over the years, yada yada yada. Stand on the shoulders of giants and whatnot.
 

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First, you didn't mention which engine you have.

Installing cams on either 5S or 1MZ engine is more complicated than most other engines due to shim over bucket design. It requires you to measure clearances and set them by swapping shims of correct thickness, and ordering/obtaining any sizes you may need. Much more involved than engines where you simply have adjustment bolts.

Next comes tuning. Stock ECU is NOT tunable. You'll need an aftermarket piggyback or standalone altogether. Otherwise, you're just relying on stick ECU to adjust fuel trims based on O2 sensor output. It;ll work, but you'll never realize the full potential of whatever cams you get. Another point to consider is that the stock ECU runs stupid rich above 5k rpm and the engine starts loosing power because of that. Safety design, if you will. Since most HP gains come from higher RPMs, you'll have to deal with this (again, piggyback or standalone).

I got my cams from Colt Cams up in Canada. They're regrinds, and cost me about $400 with all shipping. Great guys to deal with. If you're serious and understand all the rest that's involved, you can call them up and they can make a recommendation based on what your goals are. Few people on the internet will be able to tell you more about cams than an actual shop than makes them.
 

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Discussion Starter · #4 ·
First, you didn't mention which engine you have.

Installing cams on either 5S or 1MZ engine is more complicated than most other engines due to shim over bucket design. It requires you to measure clearances and set them by swapping shims of correct thickness, and ordering/obtaining any sizes you may need. Much more involved than engines where you simply have adjustment bolts.

Next comes tuning. Stock ECU is NOT tunable. You'll need an aftermarket piggyback or standalone altogether. Otherwise, you're just relying on stick ECU to adjust fuel trims based on O2 sensor output. It;ll work, but you'll never realize the full potential of whatever cams you get. Another point to consider is that the stock ECU runs stupid rich above 5k rpm and the engine starts loosing power because of that. Safety design, if you will. Since most HP gains come from higher RPMs, you'll have to deal with this (again, piggyback or standalone).

I got my cams from Colt Cams up in Canada. They're regrinds, and cost me about $400 with all shipping. Great guys to deal with. If you're serious and understand all the rest that's involved, you can call them up and they can make a recommendation based on what your goals are. Few people on the internet will be able to tell you more about cams than an actual shop than makes them.
5S-fe. I think I might get a piggyback, unless a standalone is easier to program? I know a guy that writes professional tunes so I can always ask him.
And, well... should I just get the buckets reshimmed? Seems like that might be easier, too...
 

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5S-fe. I think I might get a piggyback, unless a standalone is easier to program? I know a guy that writes professional tunes so I can always ask him.
And, well... should I just get the buckets reshimmed? Seems like that might be easier, too...
There is plenty of information on piggy back vs standalone out there, but if money is no object and you don't have to deal with emissions crap in the state you're registered in, a standalone gives you more options and can be easier to tune.

As for buckets, not much easier, really, as you need to measure the clearance and all the buckets anyway, and do the math. Some of the shims you have might be good for other valves, and they tend not to wear much. Of course, if you can foot the bill, get the newer 1ZZ shimless buckets (one piece bucket in different sizes, no shims).
 
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