Are you guys retuning, or doing a straight comparison when changing the ACG's? I see major changes in fuel trims and AFR's due to increased/decreased EGR (I expected some change but not this much), and performance also changes due to increased/decreased ignition timing of course. I'm wondering if you guys are recalibrating airflow and retuning after every change so that you get a good baseline.

Also, I'm starting to wonder if everyone's settings are in reference to properly degreed cams, given the widely varying results. Is it possible that retarding or advancing cams for some people is really just bringing them closer to 0, rather than going away from it?

So far I've had decent results with the exhaust retarded 2-3* and intake at 0*, with no other changes. Power increased, and seemed to move just a bit higher in the RPM range.

Retarding the exhaust 2* and advancing the intake 2* seemed to improve power somewhat, and unexpectedly smoothed out my idle a little (which was pretty smooth already). AFR's were really lean initially due to the increased overlap and EGR, and required quite a bit of compensation to keep from pegging the fuel trims. I need some more experimentation with this setting.

Retarding both the exhaust and intake by 2* was surprisingly just craptastic. Power was down by around 70 HP, but a lot of this was probably due to a drop in ignition timing that I didn't compensate for. Even with more timing, I don't have a good feeling about this setting. Power may be increasing higher up in the RPM range, but I don't want to rev my stroker/stock head that high to find out.

I'm currently testing 2* advance on the exhaust, and 2* retarded on the intake...along with 4* of ignition timing advance across the board. To be honest I can't tell a whole lot of difference between this and the optimal degreed settings I was at originally. If anything, the butt dyno says it is down on power and just feels 'off". (I adjusted the ACGs to this last night and have driven around a bit, but haven't been able to get a log to study yet). I need to run it some more, do a little tuning, and see if there is any power hiding in it.

My conclusion so far is that slightly retarding just the exhaust, (and possibly adding some advance to the intake along with some retuning) will probably give the best results on my car... but to be honest I just haven't seen any "HOLY SHIT!" type of results that couldn't be achieved with some different tuning on the original degreed values.

My gut says I'll probably end up running about 3-4* retard on the exhaust and 0-1* advance on the intake...but I still have some more testing to do.

This is a great tread guys, I'm subscribed.

I've been wanting to degree my kelfords 272 as there straight up right now. Just recieved my solid lifters so now I only need a degree wheel and I'm good to go. I did how ever put down 563 whp last week in 93% humidity and uncorrected numbers with the cams straight up. There a potent cam IMO.

I've been curious on which way to advance or retard them to get the results I want, which would be little quicker spool and shift my torque curve to the left some.

All the info so far guys has been great, I'm going to start frequenting this site more, you guys are some smart fellas!!! not that I didn't think you were. Just seem to spend more time reading on link lately.

So far the best results are -2 ex/0 intake.. I might move the intake +1 to see what it does. Its defidently noticable.. I finally made it under 2.0 70-90 mph with that set up at 23psi on the stroker.. I hit 1.8xx when I was streaming.. I had captured a 1.97

viperlp01 said:

So far the best results are -2 ex/0 intake.. I might move the intake +1 to see what it does. Its defidently noticable.. I finally made it under 2.0 70-90 mph with that set up at 23psi on the stroker.. I hit 1.8xx when I was streaming.. I had captured a 1.97

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Just remember to retime your base ignition after each time you change the intake cam angle. Start advancing it. I bet you start seeing some mega air flow +'s at about +3 intake -3 ex.

After more testing, my best performance gains come at -2 exhaust and 0 intake... the same as John sees on his 2.3L, so maybe it's a stroker thing. Advancing the intake doesn't gain much; if anything it just seems to flatten out the power up top and puts my already knock-happy motor closer to the limit.

Ya I have been pulling off some nice timing advance and it feels great with those settings. I pulled another 1.8 70-90 yesterday with 23 psi on e85.. My 850s are damn near maxed out touching 89%idc..

I got my cam card with all the specs on it. What am I suppose to do with it now? How does this help to degree my cams?

gsx4g64 said:

I got my cam card with all the specs on it. What am I suppose to do with it now? How does this help to degree my cams?

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Assuming you have adjustable cam gears:

4G63 Camshaft Degreeing

'92 TSI Complete Rebuild From Firewall Forward - Part 12

Boosted98gsx said:

I'm on FP3's. I don't have any numbers save some seat of the pants dyno guesstimates. After advancing the intake 5* and retarding the exhaust 6* there was a monumental increase in high end power. The turbo spools up a little faster, and mid range torque is also very nice. It makes driving around on 15psi with the HTA3582 about the same as 20 psi felt prior to the alteration.

Edit, and it went from sounding like OEM cams, to this..

You must be logged in to view this image or video.

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try the exact opposite for shits and gigles.. i think you'll see the high end power comes with less over lap. I had a good pull in the top but it fell short about 7200 with -4 exhaust and 0 intake (on gears) when i decreased overlpa if was much better at revving past the 8k mark willingly...more overlap spools the turbo fast and all at once but you will fall short when manifold pressure in the exhuast is higher than the intake pressure and there's no scavengine happening, just spoiliong of the new charge...

The 458hp GTO i ran last night probably would have taken me in the top before i did this to my cams, but less overlaap feels boggish in the low nd but once she revs up whoooooo..boy!!!!

calan said:

After more testing, my best performance gains come at -2 exhaust and 0 intake... the same as John sees on his 2.3L, so maybe it's a stroker thing. Advancing the intake doesn't gain much; if anything it just seems to flatten out the power up top and puts my already knock-happy motor closer to the limit.

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On my old 2.3L steel rod 9.0:1 motor with the GT4088R on HKS272's, I was degreed in at 3.5 degrees retarded on the exhaust cam, and 3 degrees advanced on the intake cam (-3.5/+3) produced the highest numbers overall at the loss of 300-400rpm vs. -2/+2 degrees which produced the highest torque band for me and earlier spoolup on Crower single valve springs.

Currently, I am running a 292-degree high-lift ~0.510" cam at the same -3.5/+3 degrees on my aluminum rod 8.2:1 stroker on the BW475 with Supertech dual HP springs.

I did alot of runs on the 272's on the dyno and these were the best numbers for me for peak HP. The 272's were just too small to maximize power on a 2.3L. Don't get me wrong; they still did 740AWHP/696TQ at 49psi with the Magnus SMIM; the other custom cams with the upgraded valve springs on the Beyond Redline SMIM made 766AWHP/712TQ at 42psi.

Was wondering if you were gonna jump in here. If anyone would know about cams on a stroker, it would be you.

Just out of curiosity, what did you readjust your base timing to when running the 3* intake advance?

Thanks Tim!

Crank pulley / AEM crank advance was 15 degrees on AEM EMS; I forgot what the crank pulley showed on the timing belt cover.

My idle timing was around 6 degrees from 500-1500rpm between 0-15in/hg on the GT4088R. Boost comp map.

My idle timing was around 15 degrees from 500-1500rpm between 0-15in/hg on the GT4088R. Hybrid Boost comp map.

Bringing it back...

Does anyone have any new numbers/results/opinions to post up?

calan said:

Bringing it back...

Does anyone have any new numbers/results/opinions to post up?

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I agree on bringing this thread back, its a great topic.

I just finish degreeing my GSC S2 cams so I just need to get motivated and drop the motor back in. Based on GSC's choices in Lobe centers imply they are aiming for less overlap than stock but the increased duration might negate some of that adjustment. I should be able to start gathering an interesting data baseline and then I will start tweaking.

Glad to see this thread back to life

I don't have any real dyno numbers to post, but with the addition of the pte6776 DBB turbo (as well as a head rebuild from a broken t-belt) i've been playing with my cams a little more. Onc ei got them zero'd out i tried playing with them in the typical manners of whcih are said to help spool and so forth but to this day i'm still seeing the best results by removing as much overlap as possible (or within reason for a DD car)

I'm still running DKS 264/272 cams, with Fidanza gears

For cam timing i've settled on my past setup with a few more degrees on each cam gear (from the zero baseline as set with dial gauges) the exhaust cam is advanced by 4* and the intake cam is retarded by 4*. Hardly any notable difference below the curve of where the car can make enough power to get out of it's way, but the mid range and top end showed massive improvements over retarding or advancing both gears together, as well as increasing overlap witch did harly anything worth mentioning (i feel this would be more helpfull fo those with small turbos looking for a little more punch right on spool up)

With the +4 exh, and -4 int. settings, I'm averagin about 15-17 in/hg at a 1000 RPM idle (ambient weather being the factor for variance) And with the A/C running the idle is still VERY stable running the higher ignition timing and still holding about 12-13in/hg of vac with a small decrease in idle speed due to the load of the compressor and the haltech not being set to compensate for the A/C being active with an idle speed of about 850 RPM according to the data logs.


I'm seeing ignition timing of 17 - 19* across all load cells at the idle range, those being 10* at zero RPM, then 17* at all load cells in the 500 RPM range, and 19* on all cells at 1000RPM. From there i ramp up and begin the curve as follows

1500 RPM at max vacum (although i don't attain the full vac) is about 24*, again on all cells, and by 2000 RPM i have 24* at 0 vac and 0 boost, with timing being 26* at -30 in/hg and tapering to 8* at full boost (as if this turbo could maek any boost at 2k RPM ) and linear riding to 36* at -30 in/hg, remaining at 24* at 0 vac/0 boost.

the higher ignitiopn timing at idle and just off idle makes for a VERY smooth idle as well as great response to a blip of the pedal when preparing to leave a light or stop sign in DD style situations

Also since i'm running speed density i have no way to express my airlfow in the common terms associated with the DSMlink guys, but by measuring AFR's plotted against RPM and injector pulse width the decrease in overlap still shows the widest overall gains (basically what i'm doing is aiming for a constant AFR and seeing wheather or not i need more or less fuel to maintane the targe AFR)

I'm hoping to sell this turbo and pick up an HX-35 and some bigger injectors so that i can schedule some dyno time for the final setup and at that point i will play with the cam timing leaving all other factors alone and see what the rollers have to say in comparison to my math from the logs and general impressions from seat of the pants testing.

Bringing this back to life with my results.......

I'm currently running a 2.3L with Delta k272 cams(mods in profile up to date). I've been playing around with the cam gear settings lately. I haven't been to the dyno but have been keeping track with 70-90mph times. The best settings I've had so far have been with 3* retard on the exhaust and 3* advance on the intake, 1.35 seconds. In comparison, 5* advance exhaust and 5* retard intake netted a 1.70 second 70-90mph run. Boost seems to come in quicker with less overlap, but comes in harder with more. All pulls were done with the same WOT tune and 5* btdc ignition timing. Next I might try out 3* retard exhaust and 0* intake.

I thought it was a cool thread to join in intil halfway through I noticed the date.

On my 14b setup I have the car pretty dialed in that any gear change would affect my et and mph a lot. I'm running crowers 264/272 cams and have been planning to at least degree the cams to see where they sit. Then start messing with them and see what happens. I know I need all my power between 4500-7000.

I've played with cam gears a lot over the last 6 years. Mostly on FP4R cams. For top end performance like I'm generally after on the race car, retarding both cams some amount helps. One small change last year picked up from 168 to 171 mph. On the other side of the spectrum, Thursday with the Mighty Max (also FP4Rs), which is a 3 speed auto, stroker, with a 50 trim, retarding the exhaust a bit and advancing the intake a bit improved spool up dramatically (gears were previously on the race car with settings for top end power, and I never changed it all these years). Similar to the settings I used to use to spool the race car in 2008 but not as far. It went from ~5 second from WOT to my 3750 rpm 2 step and ~9 psi boost, to ~2.5 seconds to the 2 step and 14 psi in another 1.5 seconds. There is also some ECU trickery involved to get those boost numbers. Track testing later this week will show if there is a loss in performance. It's also worth mentioning that when compressor limited, a "worse" cam gear setting may not show up as a appreciable loss in performance, but as higher boost for the same airflow. I've seen some really bizzarre shit in this regard, especially on my old 2005 EVO with cams that were ground way off center.

Something worth mentioning along with cam gear settings is back pressure. Exhaust:intake pressure changes things noticeably, but I'm not expert enough to give any good advice there. Just be aware of it in your testing if you change setups often and look for certain trends. If you run the same setup regularly you can ignore it and just tune the cam gears for best performance.

Some people like to set the cam gears to factory specs with the cam card, but I've never bothered to do that. After doing that, I feel the very next thing you should be doing is going to the track and finding what settings give you the performance you're after, so why not skip the middle man and get right to it.

95GSXracer said:

Some people like to set the cam gears to factory specs with the cam card, but I've never bothered to do that. After doing that, I feel the very next thing you should be doing is going to the track and finding what settings give you the performance you're after, so why not skip the middle man and get right to it.

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Because some not so high quality cams could be off by as much as 5-8* from factory. Imagine how long it would take you to find the sweet spot at the dyno or track.

I've experimented a little with cam gears on a stock engine with stock cams and a gtx76. The best result I've gotten was retarding both cams, which sucks because now my car is totally out of fuel pump.

One thing that's confusing is whether or not everyone is using these settings FROM their cams respective degreeing recommended by the cam card or just from zero on their gears. For instance let's say I dial my cams in to their card and it turns out to be retarded 4 on both. Would I try everyone's settings from retarded 4 or from zero? I apologize if I missed something.

I'm with Kevin, I just install the cams straight up with the gears zeroed and adjust from there. No point in degreeing with the cam card if you're going to adjust anyways.

YZFR1 said:

Because some not so high quality cams could be off by as much as 5-8* from factory. Imagine how long it would take you to find the sweet spot at the dyno or track.

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I've had cams that were over 20 degrees off, so you've failed to impress me. But that's a valid point. If you suspect your cams could be off significantly, by all means figure that out first. But for the majority of high quality and trustworthy cams, I still feel it's a waste of time if you intend to fine tune them anyway.

Jake, that's a good question, and I doubt you missed the answer to it. I think you can expect any given values to be from zero on the gears, since despite the number of people that recommend degreeing cams, so few people actually do it (and even fewer do it right IMO). But I would make the point that the absolute value is useless to people anyway. Don't worry about using the exact same settings as someone else. Look for trends and start adjusting in that direction to see what happens, based on what you're trying to achieve. You'll notice in my post that I didn't give any numbers, only direction and perhaps a vague indication of magnitude. Every car is different, and God forbid I suggest someone adjust their cam 4 degrees in some direction and that bends a valve for them. It's up to each person to determine what is safe for his setup.

I did start to degree my crower 64416s (264/272s), but only to see where they where at in comparison to the cam card. Right now they've been set to zero. I only got a little info on the intake cam and it started showing that I needed to retard the cam like 3degrees. Since I'm on a short and low power band I figured retarding the gears might gimme a negative affect.

I would like to play around with lobe separation and of a small sweep to see what's gonna work. If I know how far off the card I am I should be able to pick a better cam that would yield positive results.

95GSXracer said:

I've had cams that were over 20 degrees off, so you've failed to impress me. But that's a valid point. If you suspect your cams could be off significantly, by all means figure that out first. But for the majority of high quality and trustworthy cams, I still feel it's a waste of time if you intend to fine tune them anyway.

Jake, that's a good question, and I doubt you missed the answer to it. I think you can expect any given values to be from zero on the gears, since despite the number of people that recommend degreeing cams, so few people actually do it (and even fewer do it right IMO). But I would make the point that the absolute value is useless to people anyway. Don't worry about using the exact same settings as someone else. Look for trends and start adjusting in that direction to see what happens, based on what you're trying to achieve. You'll notice in my post that I didn't give any numbers, only direction and perhaps a vague indication of magnitude. Every car is different, and God forbid I suggest someone adjust their cam 4 degrees in some direction and that bends a valve for them. It's up to each person to determine what is safe for his setup.

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I feel like it's something everyone should establish before they post online also. It's hard to determine what trends do what in the thread due to the fact that no one talks about their baseline. For all we know they can be going from crazy overlap to where the cams are actually supposed to be. Imagine that they perform better when they're set up closer to how the factory says to do it. Not to bash anyone, as I just degreed mine to the card and called it a day, but it would be nice to know where each set of cams likes to move and how sensitive they are.

I don't really disagree, but I still feel like it just comes down to testing it. Even if you knew exactly how the changes worked for half a dozen cars, yours is still likely to be different. I was able to sweep both cams (probably 6-8 different combinations) in a couple hours at a track rental and dropped my 16g time from a 10.6x to a 10.31. No matter where my cams were when I started, I would have still ended up at whatever settings got me that 10.31.

It's also possible that I'm only thinking of this from a drag racing/ET perspective, which I'm often guilty of.