ok, here we are.

I took the insurance off the Tercel because now I want it to be a wintercross car, ONLY, so now its time for a little more power than 60 hp.

check http://enormouslysideways.net/cams.html please and let me know what you think for cam:

I want max power, screw drivability, I have a Weber 32/36, getting the head shaved as much as i can, pocket porting it, making my own tubular exhaust manifold and much stronger valve springs. I don't care if I move everything up in the rev range, as long as I don't have to rev past 7-8 grand too much, I'll be happy.

Thanks.

- R

OK, to assist myself, I have tried a Desktop Dyno program...

check out http://calgaryvolvoclub.com/Dyno2000.zip

extract and save somewhere, run the Dyno2000.exe and check out the contents of tercel!.dyn




Thanks.

- R

The problem with Desktop Dyno is that it doesn't take cam lobe shape into account. Look at the 278 degree cam and the 284 degree cam - seat to seat they're only 6 degrees different, but at .050" they're 32 degrees different! The 284 has MUCH more low-lift duration than the 278, even though the overall duration and lift numbers are close to one another.

The port flow can determine RPM range that a cam works best in as well. My mini had a 288 degree camshaft with .388" lift (itty bitty valves, so lifting more didn't help the flow) and it was a perfectly docile 2500-6500 RPM engine that had a nice lope at idle. Okay, it was closer to 13:1 compression ratio...

Which brings up another point - your dynamic compression ratio will be affected by your choice in cams, and at 9.5:1 you don't have alot of compression to give up. The 260 would probably be happy and the 278 might still work, but I'd bet the 284 would be pretty gutless and peaky. The 260-70f is pretty close in duration to the cam that's in Ian's and my cars, and neither of them have more than about 9.5:1, but they're also pretty rumpy. However, that cam has a 106 degree LSA, compared to our 112, and that's a big difference in the amount of overlap, which dictates your idle and low RPM power. (Tight LSA gives a narrow/strong torque curve, while a wide LSA gives a broader/softer curve.)

If your valves flow poorly you can get more air thru them by giving them a longer low-lift lobe, but if they flow well that will give you a really lazy bottom end. The cam and heads really work together, if you see what I'm saying, and without knowledge of one it's hard to choose the other.

Do the Toyota boys know anything better? What about the cam grinder - what are their recommendations? They usually know best, and should be happy to help you choose the right cam for your engine.

Unfortunately, nobody knows anything about the 3AC, and the like, three people who know anything about the 4AC (the big brother) all don't want to share their secrets (paradiseracing.com for example).

Schneider cams is the grinder, its a one man operation, guy is swamped, answers his emails at 11pm our time (and he's on the east coast) - and I know for a fact he bought the dimensions to these cams from like HKS or someone, he just makes 'em... knows very little about em.

And yes, as you can see in the screenshot, I don't have very large valves either, and absolutely nothing flows very well in my engine.

Also, yes compression at 9.5:1 is after I get the head shaved ... its only 9:1 stock i believe.

- R

Also picked up this little nugget:

Stock cam - .197" intake & exhaust cam lift 191 degree intake & exhaust duration.

OH MY GAAARSCH

Well if HKS designed all those cams, there should be some info or old sales literature, or something, no?

And if that original cam is 191 degrees seat-to-seat and .197" VALVE lift, well heck, ANY of those aftermarket cams will make a huge improvement.

What's this about a 4AC? Will it fit?

I agree with Matt 100%, also realize that engine displacment also have a large effect on cam profile, the larger the displacement the more radical a cam you can use. So a cam with spec's similar to what Matt and I have in the 5.0L would be extremely agressiv on the 3AC.

Lift, make sure you check your valve to piston clearences, no idea how much lift you can use with with stock pistons and your head design.

Raz, as Matt said look at the HKS site and try to compare engines with similar displacements and configurations (1300-1600cc, 8 valve engines, 9.5:1) and see what people are using.

People are using a ~280 degree cam on their 4ACs, and yes, the 4AC is a direct bolt in, just use your old flywheel, starter, intake manifold and head if you want, head is the exact same.

The plan is if the 3AC bottom end breaks, then its 4AC time, there's always a few at pick your part.

And yes, the stock cam is insanely weak, its like.. like someone just shoved a stick in there and glued some ridges on it.

- R