SILVER SURFER

I know I ramble, and you kids all seem to have A.D.D. these days, so I will try and keep it simple. These cam adjustments gave me MORE POWER AND GREAT IDLE/LOW END! Much better than 0/0, 2/2, or 3/3.

Give it a try, do some actual testing, then come back and tell me if I am right or wrong.


Smogrunner,

I really don't know, could be? But I do know how you can find out

Deceit

iTrader: (6)

Oh, I know. I've heard some horrror stories of camgears losening and/or failing, so I wanted to make sure that wasn't going to happen again . I'm probably going to end up with the Unorthodox, or Vishnu.

Eric, you never cease to amaze me with your information, thanks again.

robertrinaustin

iTrader: (5)

You must not have read his post. He makes more power with better idle and low end torque. Sounds like the best of both worlds, better than stock idle and improved performance.


Edit. Sorry, Eric already responded similarly.

MalibuJack

iTrader: (5)

I'd love to see some dyno graphs.. This is the second time I've been "advised" of this type of timing, I am most certainly going to try it.

It does make perfect sense with the idle, the split in timing reduces the cam overlap by about 3 degrees, definitely would be enough to shore up the idle a bit. It will also shift the power band down a few hundred RPM into an area where the torque curve falls into a range where most of our driving happens. Additionally the HKS Cams continue to make power well into the higher RPM as long as you can continue to get air and fuel into the engine, so its a very small sacrifice at high RPM (Where most of us would probably never benefit from anyway)

Shahul X

iTrader: (3)

very cool info.... 1st people said no cam gears, now everyone says to use cam gears guess it doesnt hurt to have them...especially if this is true info (which I have no doubt it is)....

You say I need to add a little more fuel.... would a regular AFC be sufficient?

-Shahul

MalibuJack

iTrader: (5)

If you are running upgraded injectors, you probably would have to adjust very little.. I've never used the s-AFC to adjust idle (0-1000 rpm) since the ECU runs closed loop after its warm.. you may find that it may idle a little poorer than normal until after the car warms up and goes into closed loop.. it should "learn" to add a little fuel at that point, but I'm not certain. Since he's running a standalone, he does need to make that adjustment manually.

The good news is when the car is running open loop at idle, you can adjust fuel slightly with the s-afc. Just not sure how much of an improvement you'll get. Just remember its the LO-TH point since your adjusting for 0% tps and you can adjust that across the board if needed.

SILVER SURFER

I also disscussed this topic in a different thread, since more people are seeing this one...

I have a friend with a road dyno, we are planning to do more test and tune with that, get it dialed in better on the street, then I will go to the chassis dyno for some numbers. I will keep you guys updated and I look forward to seeing how this works out for others.

When I did my initial 40-100MPH testing it was late evening 55-60 degrees, 7.08 - 7.3 seconds. I did a few pulls during the day (around 70 degrees) my best 40-100 was 7.5-7.8. Just shows you how even minor temperature changes affect power, especially when your running the turbo near it's limit. (This was with around 1.4 bar, 93 oct)

I did these 40-100MPH acceleration tests when the car was almost stock (exhaust and BC), I was seeing high to mid 9's. I also found it was a lot faster starting in second gear and doing the 2-3-4 gear change. With my current state of tune I found just using 3rd 4th gear was just as quick as the 2-3-4 method.
If you want to try it, here is my test method:

Find a relatively flat SAFE stretch of open desolate road, (no side streets or urban areas please.

Get a good stop watch, start around 20MPH and punch it, when you see 40MPH hit the watch start button, at 100 hit it again. It's not a 100 percent accurate but I was surprised at how consistent my results were. Run both directions to rule out wind and road irregularitys, and keep in mind that enviromental conditions (temp, humidity, barometric pressure) can make huge differences in your numbers.

This little test was started by Limey and his dad, there is a good thread on it buried in the Drag racing forum. It was a pretty good thread until I and a couple others hijacked it arguing about dynos .

umiami80

iTrader: (1)

Ok are these you WHP numbers with your timing improvement? Also which type of Dyno was used? Just trying to compair apples to apples here.


I have an EXTREMELY smooth powerband with my 272's and a flash.


At 3500 RPMS< my numbers are identical to yours, amazingly to the exact point. 150WHP and 250 torque, I have no cam gears nor any adjustment.


At 4000 RPMS the story changes a lil on my Evo, power shoots to 250WHP and torque shoots to 334.10, and also my peak. Your torque and WHP seem to be off a lil, I understand the differences but I feel that if our WHP and torque were dead right before max boost and then shoot up to 2 dif points, there is something to look at.

My car was Dyned and tuned at Turbo Trixx, do they and Alamo use the same Dyno?


MY max WHP is at 7300 RPMS and 324.06 and it is a very smooth climb up from 3500.


Also my torque curve follows yours pretty close, so It could be just a Dyno variation and nothing else but a Dif dyno reading a dif car on a dif day. But then I see no added benefit of adding Cam gears and adjusting the cams other then a better idle. I also do not understand that if you reduce the timing, won't that reduce the power as well?


BTW I wiill try to post a pick of my Dyno sheet tomorrow....

SILVER SURFER

No, if you actually took the time to read my entire post you would know that, (it's written right above the graph). This graph is showing stock cams compared to right after installing the 272 cams, without any additional tunning for the new cams.

AWD Dyno jet 248c/224


I agree, are your numbers SAE corrected? Or is that actual WHP done on a cold day? It was 78 degrees when this test was done, and I am running a CAT. I have found that not only do you make considerably more power in cooler weather and no cat, but the turbo spools faster and carries boost much better at high RPM, especially when it's cold.
If my guess regarding your test conditions is correct, (and I think it is), our power levels were a lot closer than they first appear.
Again this graph is before I started playing with the cam gears.

I haven't gotten to the dyno yet, but my butt dyno and acceleration testing show a significant power increase, and the low end/idle are freakin awsome.

No not exactly, cam timming is not like ignition timing, where more is always better for power. Cam timming is all relative to your engine cycle (intake - compression - power - exhaust). It gets very complicated with many variables and I won't pretend to completely understand all of the dynamics of this system. But here is what I have gathered so far (this is my first piston engine project, so corrections are welcome).
Keep in mind that right after the exhaust stroke, the intake stroke happens. So retarding the exhaust cam and/or advancing the intake cam will increase overlap. Overlap at idle and low RPM is no bueno, it either winds up contaminating the intake stroke mixture and/or some of the intake mixture ends up going out the exhaust. Either way the mixture in the chamber ends up lean, even though your wide bands says everything is fine, this is why you need to add fuel at idle with increased overlap.
Apparently during the exhaust stroke the engine never gets rid of all of hot spent exhaust gases. At high RPM's your intake/exhaust stroke time durations become much shorter, so increasing your cam durations and overlap, combined with the higher air velocities, you can get rid of more of the hot exhaust gases making more room for the cooler intake air fuel mixture, thereby making more power.
If you have a lot of exhaust back pressure, after a certain point this does not work so well. The increased overlap winds up contaminating your intake mixture with hot exhaust gases, actually causing a power loss and increasing the possibility of detonation.
So retarding the exhaust cam and/or advancing the intake cam will increase overlap, and likewise the opposite is true for reducing overlap. Remember that all of this cam timming is relative to the piston stroke position and cam profiles. From what I have seen, advancing the intake into the exhaust stroke does not work well, retarding exhaust cam slightly into the intake stroke seems to work best for increasing overlap.
With lots of back pressure (like from the stock turbo), increasing you overlap does not seem to buy you anything (except reduce low rpm torque and crappy idle), and at a certain point could actually be detrimental to power generation and reliability.

Adjustable cam gears allow you to fine tune your overlap to make the best power with least amount of low RPM/idle degradation for your particular configuration. If you use a well designed adjustable gear, (and remember to properly tighten the locking bolts), the chances of them "flying apart" are slim to none.

This is just a hobby for me, I am not a engine builder or tunner, so excuse me if some of the termonology or theory is slightly off. But the test results have and will speak for themselves.

Anyone else try this yet? I would really like some feedback.

I look forward to seeing it.

Kind regards,

Eric

Fas4dr

iTrader: (23)

Well I just got back from testing the car out with these settings and I have to say is wow!

The car purrs like a kitten at idle to the point that I almost forgot that I have cams in the car.

On the test drive I had my palm logging Rpm, timing, and airflow. I compared these logs with some logs I made about 3 days ago with the cams set at -3/-3. Timing advance was alot smoother with the new settings and I noticed on the wideband that at high rpm's, the car was a little leaner than before.

I did lose almost 2lbs/min in airflow but I have to say that the other night of logging it was about 30 degrees cooler so I am sure it had some effect on airflow.

I am definately keeping the cams at this setting as long as I have the stock turbo.

Thanks Silver Surfer for taking the time to test.

Oh by the way, the car is running a SAFCII w/stock maf.

mhgsx

iTrader: (6)

When you were trying the different cam positions, did you find that you needed to fine tune the fuel at idle?

Shahul X

iTrader: (3)

FAS4dr .... your using an SAFC? (im using the 1st one).... need to invest in a UTEC soon, but anyhow...

Im interested in doing this same thing...can you let m know what mods you have an your SAFC settings with the cams? are you adding fuel down low, have a upgraded set of injectors, fuel pump etc.... THANKS!

-shahul

Aby@MIL.SPEC

iTrader: (161)

How much power can be gained by going to the 272 intake instead of the 264 intake cam? I have seen the ams cam compare & the 272's made more on top & less down low. +/- 8-10hp with the power cross over @ 5,500.

However, I dont recall seeing what the cams are timed too?!

Has anyone seen this type of compare done on an evo?

Silver surfer, have you driven a car with the 264 / 272 combo vs your 272's?

I am getting my cams next week & I was planning on the 264/272 combo.

But now???

Fas4dr

iTrader: (23)

I have an upgraded fuel pump, Ams front mount, Unorthodox intercooler pipes, 3" turbo back, manual boost controller, 272's, and Fidanza cam gears. The last things I added was the cams and fuel pump. Before this I had the afc zeroed out. With the pump and cams I had to lean things out to about -10 up top to get an 11.8 a/f ratio. Low throttle is still all at zero and High throttle I start to lean things out at 4Krpm to 8Krpm.

Your best bet is to invest in the tuner or another type of wideband when you go with the utec to compliment its datalogging capabilities.

SILVER SURFER

I think this is going to be repated often in this thread
Thanks for for the feed back and essentially validating my results.

I found the knock count was so low with these cam settings, that I later added another full degree of timming across the board. And it still had less knock and pulled even harder.

I also noticed it ran a little leaner, with the same fuel and airflow. I attributed it to a more efficient combustion?


30 degrees will make a significant change in airflow, that's why people hit fuel cut in the cooler winter months. My testing was done over a relatively small temp change, trust me airflow definiately improves.

I also found a huge improvement with these settings, but keep in mind, this was kind of just a down and dirty quick calibration/testing session. With more time and precise instrumented testing gear, I am pretty sure these settings can be improved even further, stay tunned! There were also a few other combinations that I did not have time to try, I also did not try doing finer adlustments to say 1/4 or 1/2 degrees.

From what I can tell the benefits are just literaly everywhere, after driving it around for a couple of days I am really impressed with the spool up/torque hit, it may actually be better than the stock cams! And it just dose not seem to let up at all. I won't know for sure untill I get on the dyno, it happens so fast but I swear it's spooling well below 3500 RPM now in third gear! Did you notice this as well? Besides the idle and low end, do you think your car faster?

I don't know, I have only driven one with straight 264's, they also give a nice power gain, but it would seem that the 272's have more potential. After this experience, I cannot see any real benefit too the 264's, unless of course you don't want to get cam gears.
I will get more quantifiable data, as I am sure others will also over the next couple of weeks. Maybe wait and see how it develops but at the momment it looks very promising.

I know there are a bunch of you out there with cams and gears, grab your allen and 17MM wrench and start tweaking.