S2S Tuning Cam Development...5s-fe..Discuss!

[erioshi]

Originally Posted by Weasy2k

I hav put piggybacks on N/A vehicles before and managed as mentioned a smoother power band with an increase of 10-20whp depending on the vehicle.

You will not really be able ot adjust hte cam timing unless you manage to make an adjustable mesh gear that moves the 2nd cam.

I've actually been considering counting teeth and jumping the cams a tooth or two depending. With all the dyno work & testing that we did on my Evo, I'm pretty sure I could find a cam timing compromise that would be beneficial. Unfortunately, dyno time gets spendy and changing the cam timing on Toyotas isn't quick. And as Tom said, bigger cams would really make a difference, too. Another interesting thing to note is that it's not uncommon for HKS cand other cam companies to change the degree of the lobe centers when the engineer their cams. A small change in cam timing can really impact an engine's VE.

Thanks for the great feedback on the piggybacks guys. That seems to indicate that combining good EM with breathing changes would really help things out.

[mrturrari]

Originally Posted by erioshi

I've actually been considering counting teeth and jumping the cams a tooth or two depending. With all the dyno work & testing that we did on my Evo, I'm pretty sure I could find a cam timing compromise that would be beneficial. Unfortunately, dyno time gets spendy and changing the cam timing on Toyotas isn't quick. And as Tom said, bigger cams would really make a difference, too. Another interesting thing to note is that it's not uncommon for HKS cand other cam companies to change the degree of the lobe centers when the engineer their cams. A small change in cam timing can really impact an engine's VE.

Thanks for the great feedback on the piggybacks guys. That seems to indicate that combining good EM with breathing changes would really help things out.

The problem with jumping teeth on the internal cam gears is that each one is 10 degrees cam timing with translates to 20 degrees crank timing. I don't think you are going to be able to get a good tune from that. Cam makers change lobe centers because if they didn't then the overlap would be too large for the duration.

I think the best way to do an aggresive set of cams for the 5sfe is to have them hard welded and ground with the duration and overlap you want. Billets might also be a possiblility but I don't know about the cost. Try to get the lobe centers where you think they should be but the duration and overlap are the most important and then get a 2jzgte adjustable cam gear, have the center hole machined larger to fit the 5sfe intake cam. You won't be able to change duration but you should be able to get a pretty workable tune and be able to adjust it easily at the dyno by leaving the top timing cover off.

[erioshi]

OK - You're hitting the exact issue I figured might pop up as a problem. I haven't counted the cam gear teeth yet, but for each tooth to be 10 degrees then there should only be 36 teeth on a cam gear. I thought the cam gears looked finer than that, but as I said I haven't had a chance to count them.

I like your suggestion idea of using an adjustable gear on the belt end of the intake cam (at least that's how I interpreted it - my search for 2jzgte cam gears only turned up timing belt gears), but that still leaves the exhaust cam being non-adjustable. I would think that rather than regrinding cams, it would be less expensive to have the key-way modified on the exhaust cam if skipping a tooth isn't an option.

One other issue that will come into play when messing with cam timing on Toyota engines is that the gear driven cam is counter-rotating. Meaning that any change to the intake cam would be applied and inverted automatically on the exhaust cam - clarifying the need for a way to adjust the exhaust cam separately.

[Oteck]

unless the engine was realy under rated from factory then you won't be seing alot of gains

[mrturrari]

Originally Posted by erioshi

OK - You're hitting the exact issue I figured might pop up as a problem. I haven't counted the cam gear teeth yet, but for each tooth to be 10 degrees then there should only be 36 teeth on a cam gear. I thought the cam gears looked finer than that, but as I said I haven't had a chance to count them.

I like your suggestion idea of using an adjustable gear on the belt end of the intake cam (at least that's how I interpreted it - my search for 2jzgte cam gears only turned up timing belt gears), but that still leaves the exhaust cam being non-adjustable. I would think that rather than regrinding cams, it would be less expensive to have the key-way modified on the exhaust cam if skipping a tooth isn't an option.

One other issue that will come into play when messing with cam timing on Toyota engines is that the gear driven cam is counter-rotating. Meaning that any change to the intake cam would be applied and inverted automatically on the exhaust cam - clarifying the need for a way to adjust the exhaust cam separately.

There may not be exaclty 36 teeth but it is close. http://warp.scl.utah.edu/mr2/91-93cams2.jpg

Yes you would adjust the cams using the timing belt cam gear of the intake cam. Here are some pictures of the 5s and 2jz pulleys:

http://warp.scl.utah.edu/mr2/CamGears.jpg
http://warp.scl.utah.edu/mr2/CamGears2.jpg

You could machine out the keyway on the intake cam so it would be able to move but you would also need a way to secure it when you adjusted it. There is very little room on either side of the gears because of the design of the head so any bolts would have to be recessed. Because it is pressed on and the key keeps it from turning you would need to secure both the inside and outside where they meet. I wouldn't say it is impossible but it will be complex and difficult to fit in the space and still be strong enough to hold.

The inverse nature of the cams will not make them adjust opposite from each other. Because the exhaust cam rotates the other way and is made to do that any advance on the intake will also advance the exhaust the same amount.

[erioshi]

Thanks for the pics, the teeth are definitely more coarse than I was remembering. I would still like to see a count though, lol. I am also interested in the number of teeth on the timing gear pulley.

I wasn't thinking of trying to make the intake cam gear adjustable, just moving the key-way over a few degrees and filling in behind it. A solution (just for testing) might be to open up the key-way and then use shims to center the gear where you wanted it. Once testing was finished, then I could have a set of permanent cam gears altered to my specs.

You are right about the gears mechanically advancing and retarding at the same rate. The real issue will be the complexity of that relationship for testing. Changing the ATDC value of the exhaust cam will currently alter the BTDC value by the same amount. That means some fancy footwork if you want to move both cams to entirely different settings.

[mrturrari]

Interesting idea... the shim idea might work. If it were the right shape you could make it stay in there without any kind of fasener. It would be a real pain to change it but I think it's possible.

[erioshi]

Originally Posted by mrturrari

Interesting idea... the shim idea might work. If it were the right shape you could make it stay in there without any kind of fastener. It would be a real pain to change it but I think it's possible.

Exactly - And the fasteners used to keep the cam gears in place could also help keep the shims in place during testing.

[Weasy2k]

This is the whole reason i started this thread to discuss options. Reason being is that I am in the works of getting a dyno here and will be buying a car (beater) with a 5s in it to preform all these tests on the motor. WItht his dyno it opens up the door to making TONS of cam ideas that me and the cam grinder have.
You will see a whole new range of cams coming out soon as I continue to develop toyota cams with him.

One key thing is to get 5s cams and get them ground to a degree that i specify and throwing them in and on a dyno. Gte lots of spare sets and play.
Once i figure out the best combo I will then do a group buy on them and make billets (they are NOT cheap). The buy in on billets is HUGE and its tough to just go out there and buy some.

[mrturrari]

Originally Posted by erioshi

Thanks for the pics, the teeth are definitely more coarse than I was remembering. I would still like to see a count though, lol. I am also interested in the number of teeth on the timing gear pulley.

Got home from vacation and counted them and the internal cams gears have 40 teeth each with makes them 9 degrees on the cam and 18 on the crank. The timing belt pulley has 48 teeth which makes it 7.5 degrees and 15 at the crank.

[Mister2.2]

Glad to see you over here helping out mrturrari.

[erioshi]

Originally Posted by mrturrari

Got home from vacation and counted them and the internal cams gears have 40 teeth each with makes them 9 degrees on the cam and 18 on the crank. The timing belt pulley has 48 teeth which makes it 7.5 degrees and 15 at the crank.

Good info, and you are right, that would be a bit much to just skip a tooth with.

Do Toyota timing gears change thier orientation slightly when you flip them? Several other manufacturers allow the gear to flipped for 1/2 tooth cam gear adjustments.

If this were the case, then you could manage 3.75 degree intake cam change and match that with either the same, or 1 tooth retarded exhaust cam timing. That combination would probably be worth testing.

[TRD-CEO]

I am having a base run done on the dyno wednesday. I'm having a header and exhaust put on and then going back to the dyno. I found a performance shop here that only charges $50 a run. I'll let you know the differences. The also make custom products and said if I could get them a 5SFE head they'd love to work on a new cam for it. They have a CNC machine on site. I also mentioned to him about the fact that I had heard about spring rates not being able to handle the higher horses and he said they design and make them also. If you can find a way to get an extra 5sfe head to Charlotte, NC I can get it to him. How many people would be interested in the cam if made? I am going to see him on Wednesday and could pass the info along to see what they might charge if I can get a group order together. I don't know all the technical things you guys know, but I got the money to get the work done. Hahahahhahaha. Let me know if any of you are interested and I'll talk to him Wednesday