Lund tune bugging me

[engineermike]

Every Lund tune I’ve seen locks the cams in one position unless you’re at idle or wot. I’ve seen other big tuners do this as well.

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[shogun32]

My main reason for switching was surging and bucking in part throttle. It never felt like I had good control over the pedal. With Wengerd's tune, it feels like I'm driving any other car if you get what I mean. The pedal feels intuitive and predictable.

which just shows Lund is complete shit. They should be ashamed of their work-product. I can't believe people settle for such crap. "You had ONE job" and it's to get the damn fueling RIGHT everywhere.

 

[shogun32]

Every Lund tune I’ve seen locks the cams in one position unless you’re at idle or wot. I’ve seen other big tuners do this as well.

lazy? I mean tuning to WOT is as 'trivial' as it comes and not a demonstration of skill.

 

[engineermike]

lazy?

Some might call it “efficient”…from a business perspective at least.

 

[GrabberBargeCaptain]

I had a FRS tuned by one of the premier 86 aftermarket tuners that i added an edelbrock supercharger to (PD-type) and it had some bucking and surging at part throttle especially in cold temps (i can't remember but it was when the car was running exclusively on either DI or IDI when it first turned on) and it was absolutely infuriating, so i feel people's pain on that. I had to constantly drive around it and ride the clutch out in certain situations and it ruined my enjoyment of the car. I was going to get it re-tuned and buttoned down but by that time, CA had made it so they fail your smog if you use non CARB tunes and i said screw this (the stock Edelbrock tune was ALSO known for bucking and surging) and sold the car to Carvana for $19K.

I think part of it was Edelbrock's shitty vacuum operated bypass valve was undersized and prone to failure. Fun car when warmed up and not driving in stop and go traffic but i don't think i'll deal with aftermarket tuning ever again

 

[Forestlump]

Every Lund tune I’ve seen locks the cams in one position unless you’re at idle or wot. I’ve seen other big tuners do this as well.

I've always wondered who puts the most effort in to cam timing, and that's the guy I'd like to use next.

You'd be the guy to speak to about this,

Is it achievable to progressively reduce valve overlap as boost increases? ie adding an effect similar to "blower cams"

When I removed cats and fitted headers/exhaust I noticed a boost drop of 1.5 psi, it's being lost down the exhaust because of NA cam specs on boost.

 

[cbrtrx]

I've always wondered who puts the most effort in to cam timing, and that's the guy I'd like to use next.

You'd be the guy to speak to about this,

Is it achievable to progressively reduce valve overlap as boost increases? ie adding an effect similar to "blower cams"

When I removed cats and fitted headers/exhaust I noticed a boost drop of 1.5 psi, it's being lost down the exhaust because of NA cam specs on boost.

Cam timing can and should be adjusted per your application. You'll notice with some centris dynos where the power flatlines up top and others it keeps pulling to you let off the throttle. I can make the stock gen 3 manifold pull past 8k rpm with the power still steadily climbing. That is all in cam timing.

 

[Pistol_91]

My car idles at 750. 900 is very high. Lund sets their drivability tables to one set of cam timing instead of blending them as load increases for better drivability/power delivery. It works, I've tried it, I don't prefer it. Feels sluggish. The timing is stagnant until your foot is far enough into it to move it to a different table where cam angles will start changing. Black smoke doesn't always mean rich. Could mean too much timing. If you're on gasoline try adding some octane booster to see if it goes away.

 

[Forestlump]

My car idles at 750. 900 is very high. Lund sets their drivability tables to one set of cam timing instead of blending them as load increases for better drivability/power delivery. It works, I've tried it, I don't prefer it. Feels sluggish. The timing is stagnant until your foot is far enough into it to move it to a different table where cam angles will start changing. Black smoke doesn't always mean rich. Could mean too much timing. If you're on gasoline try adding some octane booster to see if it goes away.

Ok, that's great cheers, il try and do some logs when I get home and try octane booster, there's something amiss, I'm just not clued up enough on the tuning/ mapping side of what's going on and I've been putting off educating myself, it's another complex subject that will take time that i dont have.

Cheers for your insight though, it does make sense.

 

[Forestlump]

Cam timing can and should be adjusted per your application. You'll notice with some centris dynos where the power flatlines up top and others it keeps pulling to you let off the throttle. I can make the stock gen 3 manifold pull past 8k rpm with the power still steadily climbing. That is all in cam timing.

This is what I'm looking for, the extra efficiency from having it set correctly rather than what's close enough.

Your right, some don't fade at all, just keep the same trajectory.

Do you fancy having a go remotely?

 

[cbrtrx]

This is what I'm looking for, the extra efficiency from having it set correctly rather than what's close enough.

Your right, some don't fade at all, just keep the same trajectory.

Do you fancy having a go remotely?

I don't offer remote tuning, only in person. I don't do one size fits all cookie cutter tunes. I do true custom tuning like it should be. Sometimes it's the little things that can make a big difference.

 

[Forestlump]

Fancy a holiday to England?

 

[engineermike]

I've always wondered who puts the most effort in to cam timing, and that's the guy I'd like to use next.

You'd be the guy to speak to about this,

Is it achievable to progressively reduce valve overlap as boost increases? ie adding an effect similar to "blower cams"

When I removed cats and fitted headers/exhaust I noticed a boost drop of 1.5 psi, it's being lost down the exhaust because of NA cam specs on boost.

There are some rules of thumb I can describe here, as I find the subject fascinating.

Idle: For idle, you generally run the intake very, but not fully retarded, and the exhaust fully advanced. This minimizes overlap and smooths the idle. Of course, ghost cams are a different story.

Cruise: Ford does a simulated Atkinson cycle at part throttle by retarding both cams to the max. This extends the power stroke and shortens the compression stroke so your expansion ratio is much greater than the compression ratio, which increases engine efficiency when that is the goal. However, there is debate as to whether or not this is most efficient when you remove IMRC. I've experimented with this and found a loss in efficiency when running stock part-throttle cam timing without IMRC, but it is very hard to measure accurately. Both Roush and Whipple still retard both cams at part throttle, but nowhere the extent as stock. The Gen1 and GT500 also don't retard them nearly as much as stock Gen2 or 3 with IMRC. And as mentioned, a least a couple of mainstream commercial tuners just lock them in one position at part throttle.

WOT: For the exhaust cam, you can pretty much just set it at 15 and leave it there. There's very little performance on the table by moving it. A lot of stock tunes, even the GT500, will advance the exhaust cam at the tip top of the rpm range and theoretically there should be a little power available but we never saw it on a dyno. For the intake cam, there is a fundamental difference between PD blowers and NA/Centrif/turbo. For PD blowers, the airflow is determined almost completely by the blower size and speed so the cam timing has little/no effect on actual airflow. You're playing a game balancing efficiency and knock. In general terms, you always fully advance the intake cam at low rpm and retard at high rpm, but you wind up not retarding nearly as much as stock. More retard might make a little more top end, but less retard actually has less tendency to knock so on pump gas could make more power. As for NA/centrif/turbo, the cam timing does affect airflow so that can easily become governing, vs knock tendency and efficiency. I can't explain why, but Ford drastically retards the intake cam on the gen3 at high rpm. They didn't do this on any other coyote, including gen1, gen2, bullitt, mach1 or gt350. I've found more power on the dyno by retarding the intake cam less than stock, and that was the case on NA, centrif, and turbo. But...I defer to @cbrtrx on optimal centrif cam timing for WOT.

With very low backpressure you are most likely getting some blow-through of the charge. However, at low boost it won't be much. I've seen this on a couple of cars usually closer to 15 psi boost, and it actually dilutes the exhaust stream with air which leads to the O2 sensors getting a false lean signal. I haven't played with it on a dyno, but there may be a little power available by advancing the exhaust cam to reduce overlap.

 

[NO1CARES]

Do you have a catch can that's plumbed back into the intake? Because a catch can will not fully eliminate all the oil being sucked back through the system and this could be what you're experiencing. Vent the crank case to the atmosphere and see if this changes anything.

Everyone is quick to blame the tune but based off what i'm seeing. You have things to do better on your part to tiddy up the tune. Have you smoke tested the whole system under pressure? I've seen tight couplers leak and if its after the maf can create tune changes.

Do this before worrying about changing tuners.

 

[Forestlump]

It is fascinating, if I had access to a Dyno and the amount of cars you see, I would be experimenting with it too.

Setting them fixed to me is a waste of useful technology.

My thoughts are the same about losing it down the exhaust due to a slightly retarded exhaust cam, it's likely why I have a slightly over rich mixture as the O2 sensors are being misleading by a false lean condition and adding more fuel?

I bet the reason Ford has advanced the exhaust timing at the top end on gt500 was to lower cat temps and less blow through and not for power. Also for the more accurate o2 readings. On a side note, It might explain why you saw a slight gain in power by running cats compared to without. Less cylinder blow through on boost, diluting the exhaust, messing with O2's and also cooling the exhaust compared to the cats which heat up the gas (changing pumping losses).

Like you say the pd setups respond less to intake cam changes, that setup has all the extra boost doing the work at low rpm and the valve is open much longer in time at the low rpm ranges, once the cylinders full, the jobs complete no matter what the valves doing.

I experienced this years ago with a Renault turbo rally car and long duration cam, once on boost, it had less effect where you timed the cam but off boost it made a big difference.

I imagine the gen 3 retarded intake cam is due to the extra rev ceiling compared to the previous gens. I suspect that the gen 3 inlet manifold starts to work better at stuffing air in to the cylinder (ram tuning) than what would be lost in compression from the intake valve being left open longer at the begining of the compression stroke. But that only works at the top end. Again what advantage that has when you FI it is probably negligible as the cylinder is already full in that situation. That is what you've seen on the Dyno too.



Cheers for sharing your valuable knowledge, It's something I've been wondering about for ages and noone's really spoken about.

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