Cam tuning for boost: two tries
 

I've got some adjustable cam gears (fidanza group buy for $180!) installed and I was going to take the opportunity at the dyno day Saturday to mess with them. FE is very similar to the B hla cams and common procedure is retarding the intake and advancing the exhaust. Primary goal is to see if I can improve hp past 5500.

Looking for suggestions on how to approach it- like:
run 1 - baseline
run 2 - advance exhaust 2*, retard intake 2*
run 3 - make changes based on run 2 result

more advance?
should I only touch one cam at a time?

I realize this is a dyno day and not a tuning day, but this is a simple change that should produce a result and want to take advantage of my $45. ;)

http://i158.photobucket.com/albums/t...FEcamgear3.jpg

Knock the intake cam to full retard and see what happens. My motor ran pretty well (albeit with reduced overall timing required) at over 30 degrees of intake retard.

Hard to get it dialed in in only 3 runs. Do a baseline run, then maybe 5* one cam at a time. Next go 5* more, and if it goes down, step back the timing to less than the initial 5*, Maybe 2.5 area. Or go back and forth between the cams a few degrees at a time. I dont know, Im tired. Gears look good though.

anyone have data on lowering boost threshold with cam timing?

a couple of references I found on m.net re: cam tuning

Just looking to improve to do something on each run. I will do final cam timing when I go to tune with the new intake manifold.

Pat started a thread somewhere on cam timing but it fizzled. I think hustler was the only one to comment. :dunno: I don't think anybody here has really messed with it, but I think there's cheap power there.

If they weren't so expensive I might try it out. I have a few hours reserved on the eddy dyno in a few weeks and I only need about 30-minutes of work and I'm done (<4500rpm load runs).

on a side note:
I love the eddy control dyno. Its great to make the car do exactly what you want, over and over and over. Find your problem area, slay it.

one cam at a time!

I see it as you need four runs to find the baselines.

Intake advanced with exhaust retarded
Intake retarded with exhaust advanced
Intake advanced oh hell, like a truth table. both cams in both states.

But I do know from playing with VVT if you want top end, retard the intake 15 crank degrees and if you want low end (sub tq peak), advance it 6 crank degrees. from what "zero" on your car.. I have NO idea :)

I guess you gotta pick your goal. top end or area under curve?

http://www.motorsport-developments.c...AF245_tech.pdf
http://www.motorsport-developments.c...AF246.tech.pdf

reading now...

This mustang dyno has eddy... but I don't want to spend the dough on tuning until I've got my manifold done/installed.

What's expensive for adj cam gears? I thought mine were cheap...

I want to reduce my massive torque drop from peak, over the next 2200rpm. I want a y8s hp curve. ;)

Retard the intake cam at least 6 cam degrees from the start, and go from there. That moves valve closing from late 40's * ABDC to low 60's, which is a lot better. 40's are for economy cars, high performance engines low 60's is the new norm, upper 60's is what you'd find on say a hybussa. You'll loose a spec of bottom end/gain some economy and it will help top end a ton. You could retard intake cam timing more and get more power, but you may loose a little down low. To me, I'll give up some low end for some top end. If I wanted torque like a diesel I'd drive a diesel.

I wouldn't mess with the exhaust cam timing much. Advancing it is a bad idea IMO. It does reduce overlap and perhaps some have noted gains from advancing it on turbo motors, but in reality, that's doing it wrong. Better you would retard the intake cam enough to get overlap down close to zill and keep the exhaust cam timing the way it is. If anything you want less duration on the exhaust cam such that the valve stays closed longer during the power stroke longer so you get more PdV work and then it closes right around TDC of the exhaust stroke as to minimize overlap and reduce the amount of residual gases that will mix with the incoming charge. Advance it and you loose some PdV, retard it you get more overlap and more residual gasses to reduce power and help it detonate.

Now I shall say it: Swapping the cams around may be better for a turbo engine as the intake cam has less duration and lift and the exhaust cam has more lift and duration. IMO swapping them and playing with cam gears may be the winning combination.

Yeah, tech discussion here sucks. We'd rather talk about civics that look like BMW's.

At this point just about anything is expensive. I've done so many $200 here, $500 there, oh fuck it...$2k on suspension, oh great...a hard-top for my other miata, 2 sets of 6ULs there, big dildo here, new George Michael real-doll...I'm over the shit adding up.

I don't really want to blow another $180 on something I know very little about when it comes to dyno tuning...but the time is free i suppose.

I wished I had a real baseline before hitting the dyno. I'll be on a mustang vs. a dj and on an mbc vs. my tuned ebc. Oh, and new muffler. But I get your point, no need for a baseline since the current cam timing is a "known" disadvantage for performance/boost.

I don't think tech lacks here, it's just that most talk about what they know for the most part. Nobody here has messed with cam timing via adjustable gears (or opted to talk about it if they did). Best reference I had here was Y8s vvt info. Which is related.

What spurred me to spend the cash on these (besides the deal) was that I couldn't find a single instance where somebody didn't make big gains (relative to cost) when applied to an NA car that was then boosted. It's also an easy upgrade- cash, install and tune.

I think one point applicable to hustler's situation is getting more power per boost. If you got the same power at 1psi less, would it be worth the cost? Personally I think your engine will last w/o question at moderate power.

which one? red or blue...

http://y8spec.com/dyno/vvt_range.jpg

as Pat mentioned, start with 6 degrees CAM retard. That's what RED is roughly.

The real crime in my set-up is the ignorant tuner (mr. hustler).

Pats, advancing the exhaust cam helps low rpm spoolup.

mx5cup, you can do cam timing experiments on the street, and examing AFR's. If it goes leaner, the engine is breathing better.

Red fo sho.

I felt the same way, but when I got the dyno and saw the numbers and what it took to make improvements, I felt better. Wasting your life on reading turbo stuffs on the interwebz can have benefits. :giggle:

is that 30 degrees more overlap or less overlap?

Spoolup or power? Both? Maybe not?

Sav had his intake cam retarded 2 teeth IIRC. So that would put the intake valve event happening later, reducing overlap. Probably didn't have any overlap 2 teeth off. :giggle:

Less - that seems like a huge amount to still have the car run ok outside of beating on it.

I've done a lot of tuning on the street, but at this point in my life it's more convenient to schedule tuning time and go to a dyno. I get the biggest return for time spent.

I think what I'll do is start with the intake cam at -6. Then make another run with more retard. And on the final run I might try an exhaust cam advance for the log. I wished I could log egts - I'll try and remember to watch the gauge. I'll get somebody to drive the car while I log.

I'm thinking I might go out and do 4th gear log tonight with the MBC as a reference point for the adjustments.