Guest ZmeFly Posted November 15, 2003 Share Posted November 15, 2003 Just touching on a subject that has or seems to be discussed with the NA guys but not the turbo guys. Its about switching the cam position from the number 3 to the number one position. From what Ive read switching on the NA motor to the number one position gives a higher top end and more noticeable power in the higher rpm range. What would this do for a turbo motor?? Would it help just as well or would it not? Anyone ever try experimenting the the different cam positions on a turbo motor to see what happenes? Just a thought for a little more "free" power. Any comments or thoughts are appreciated Quote Link to comment Share on other sites More sharing options...
Guest Nic-Rebel450CA Posted November 15, 2003 Share Posted November 15, 2003 If you could show a link for the N/A thread you are referring to, I could read about that and explain how that would benefit or hinder a turbo car based on turbo operating principles. Quote Link to comment Share on other sites More sharing options...
Guest ZmeFly Posted November 15, 2003 Share Posted November 15, 2003 heres the link Cam Sproket Adjustment Thanks for some feedback Quote Link to comment Share on other sites More sharing options...
Guest Nic-Rebel450CA Posted November 15, 2003 Share Posted November 15, 2003 Sorry, I am still lost. Not sure I understand what the different positions are. I am assuming that this has some effect on when the valves open, but I am not sure what the 1 and 3 translate to. If 1 is better for bottom end and 3 is better for top end then my educated guess would be that 1 makes the valves open sooner and close sooner and 3 makes the valves opens later and close later. If this is the case, then a turbo motor should benefit in the same way, and may be able to take more of an advantage as turbo setups typically run around the top end of the RPM range. Wherever you set it, make sure you set the valve lash accordingly. Valve lash makes a big difference on performance. Quote Link to comment Share on other sites More sharing options...
Clifton Posted November 15, 2003 Share Posted November 15, 2003 Retarding the cam timing gives more top end, advancing more bottom end. The 2 and 3 holes advance it more, good if your chain has 200k on it. I run mine on 1. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted November 15, 2003 Share Posted November 15, 2003 Yeah it's a big deal with N/A guys. I would run my old built up N/A on the #3 because I wanted as much low end torque as possible, to combat the loss of torque in that same range that switching to a hotter cam caused. For better quarter times you would want it on the #1 position, which Norm the 12 sec SU dude tested and found the #1 to perform much better, and said it was well worth the loss of low end torque. Considering I do a lot more low rpm street driving I prefer the low end... I'm actually glad you posted this question though it does seem to be something no one really considers for turbo cars.... I know mine is set on the #2 right now... wonder if I should change it... Quote Link to comment Share on other sites More sharing options...
Clifton Posted November 15, 2003 Share Posted November 15, 2003 On a turbo car you have plenty of torque once you get into boost. I like having my power band up into the higher rpm range were the HP is and were I tend to be when I need it. Quote Link to comment Share on other sites More sharing options...
Guest ZmeFly Posted November 15, 2003 Share Posted November 15, 2003 Im wondering if it will help on a turbo as it does on an NA motor. Very interested in finding out if anyone has ever done this with turbo. Just makes you wonder if you should change. I hope someone has done it and can report the good or bad of it. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 15, 2003 Share Posted November 15, 2003 Why don't you just try it and let the rest of us know. It's not that hard, just use a wedge on the timing chain and it should be a 1 hour job or less... Jon Quote Link to comment Share on other sites More sharing options...
Guest d9 Posted November 15, 2003 Share Posted November 15, 2003 Very interesting, I'm not sure I understand what is going on still but I'll give it a look and try to figure it out. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted November 16, 2003 Share Posted November 16, 2003 I think, if you moved it to the #3 (the low end torquey setting) you'd probably notice a difference in off boost respons. If you were to go the other way, to the #1, since a turbo pulls so hard up at those RPMS anyways I dont know if you'd feel much difference... maybe the motor wouldn't run out of breath so soon? My turbo really doesn't feel like it's got much oomph above 5000rpm, putting it on the #1 would probably help that. Dont know why but I'd rather not do that anyways... with my N/A it was always fun to rev the heck out of it, but I have really never felt so inclined with the Turbo... only once or twice have I even had it up to 6k. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted November 16, 2003 Share Posted November 16, 2003 the cylinder pressure increase as the cam advance right? would it not become more detonation prone? I like leaving the cam straight up because I don't want any bad side effect. like the exhaust valves opening too early or too late. SOHC is a double edge sword. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted November 16, 2003 Share Posted November 16, 2003 SOHC is a double edge sword. Yes it is And yes I think it does increase the cylinder pressure... I only think that because I seem to remember thinking it also increased the #'s when I did a before and after compression test on my N/A motor. So then the #1 setting would be the least detonation prone? On a turbo motor that changes everything .... Quote Link to comment Share on other sites More sharing options...
Guest ZmeFly Posted November 16, 2003 Share Posted November 16, 2003 Getting the minds together and talking, it is true as you advance the cam it does increase cylinder pressure. Hmm, so as bastaad said, then it would or at least theoretically become less prone to detonation if the cam were retarded to the number one position. Thats food for thought. I wonder if any of our higher hp turbo guys will chime in on this. Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted November 16, 2003 Share Posted November 16, 2003 I personally think that it depends on you driving style and what you do with the car. For the street and everyday driving the bottom end torque is nice. At the track some more top end is what you would want. I have no dought that all of use have some trouble getting of the line. I've never played with to see what would havppen but, I think that the key to getting these cars to run good on the higher end of the tack is in the turbo and the computer programming. No dought that a cam adjustment or larger cam would help out. My setup engine is very close to stock and I run mine to 6300 when I go to the track and it pulls hard all the way. I remember that when I went to a larger turbo from the stock unit that the top end really opened up. I still ran out of power at 5800 to 6000 but, it was much better. Another thing about a differnt turbo is that it can be matched better to how you drive the car. Anyone play with thier timing. I set mine at 24* and that has seemed to be a good # for the turbo cars that I've had. That setting gives good off boost response and good top end. Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted November 16, 2003 Share Posted November 16, 2003 One other thing that I want to add is that a good 3" manderal bent exhaust will really help in every catagory. I did a new downpipe all the way back to the area right before the exhaust starts to go up over the rear end several months ago and that made a huge differnce. This was connected to an old 3" press bent setup that I had made yeras ago. Just the other day I did the rest of the exhaust and and again I got some gains but, not as much as before. In total I spent about 20 hours and about 100 to 150 bucks on materials not including the welder and all the other crap to be able to make that kind of stuff. The 3" manderal bent exhaust will help in both top end and low end. Right now I'm not running any muffler and it's alittle loud but, not to bad. It's kinda fun you can hear the turbo spooling up faster and much more louder since the materials are different than the stock cast iron stuff which abosrbed some much of the sound. Quote Link to comment Share on other sites More sharing options...
Guest Cusp Posted November 16, 2003 Share Posted November 16, 2003 I would imagine that any opportunity to reduce detonation is basically the same as giving more headroom for boost. If said turbo car can squeeze in a pound or two more boost by setting the cam to #1 position, that will yield more gains than going to #2 or 3 will and leaving boost alone. This is under the assumption that you have abandoned stock boost levels. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted November 16, 2003 Share Posted November 16, 2003 24 is about where my initial is set too. At 20 deg, it would stumble like crazy and th epower never really climb on the dyno. Quote Link to comment Share on other sites More sharing options...
jeffp Posted November 20, 2003 Share Posted November 20, 2003 I had my cam retarded 4 degerrs or so. But I did not take the time to degree the cam, so it was closer to 6 degrees (crankshaft degrees) The car ran well, but I did notice the real power range, at least where it wanted the most fuel and tried to go lean was at the 5-5500 rpm range. Then I put the car on the dyno and sure enough it wasthe best torque in that range. So this time I had the car apart, I decided to degree the cam and bring it strait up where it was ground to. Now I am noticing a lean condition in the 2-2500 range, and in the 6-7K range. I haven't pushed the car to hard, and am running stock boost, well 8psi and the car does well there. I haven't put my broadband O2 sensor to verify the mixture, but I am quite sure it is going lean. So today, I called and setup an appointment to put the car on the dyno and have it retuned to run at the strait up setting. I am guessing, and educated guess at that, that the power band has moved past the 5500 range and into the 6K range, fine by me. I need this data to fine trune the next grind I am going to run. My goal is to get peek hp and torque into the 6-7k range, in other words WOT. But I am still undecided on that point. You remember what the car did when I gave you a ride right James? Not bad at all, but I have some things I am working on for another build for a specific application, and I am going to need the power in the higher rpm range to get maximum topend from the setup. The thing that is not to fun about changing the cam timing for me, and for you is that you will have to play around with the AFM to get the mixture correct for the changes, and it is questionable if you can get the tuning correct with the stock system. What I would do if I were you, is buy a degree wheel setup from Summit, and start with the cam set to factory specs. Then you can advance or retard the cam timing and decide what you like best. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted November 20, 2003 Share Posted November 20, 2003 Ahh, that's what I don't like about speed-density standalone FI systems. Change anything, and it's time to retune. Of course JeffP is still running a JWT? What's up with that? The ECU should just measure the air and meter the fuel..? Quote Link to comment Share on other sites More sharing options...
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