When are cams too aggressive for a setup?
Dec 18, 2008, 08:45 PM
#1
When are cams too aggressive for a setup?
The reason I bring this up is I'm running some fairly aggressive cams, FP4R's, on my IX with stock turbo and saw no dramatic increase in performance. My idle quality and low-speed drivability has suffered and I'm just not sure I'm seeing the gains to make it worth it. My friend noticed the exact same thing except he went for the Kelford 272's on his comparably built IX. My spool and powerband did not change much with the addition of the cams. Is is possible that I could see greater gains AND increased idle/drivability quality with a less aggressive cam such as one of Kelfords milder offerings or GSC S1's or are cams just not that worthwhile on stock turbo IX's? I am working on maxing out the stock IX turbo but this is my daily-driver that see s a lot of stop/go driving every day. Thanks guys!
Specs for the FP4R's can be found here: http://store.forcedperformance.net/m...=Lancer-Engine
Specs for the FP4R's can be found here: http://store.forcedperformance.net/m...=Lancer-Engine
Last edited by Kracka; Dec 18, 2008 at 08:58 PM.
Dec 18, 2008, 09:16 PM
#2
Neither the FP4Rs nor Kelford 272s are overly radical profiles based upon the advertised valve events. However, realize that the AMS cam test involves an engine that has a CNC ported head, large turbo, and other upgrades, all running very efficiently and able to make good use of increased lift and longer duration. This is a bit of a departure from a stock EVO IX, and that will be reflected in the real-world results.
With judicious tuning of MIVEC and the fueling and ignition maps, a fairly stock IX should see decent performance benefits from the aforementioned cams with minimal compromise in driveability. The results probably won't be as dramatic as the AMS test (what everyone has stuck in their heads), but a marked improvement should be attainable.
With judicious tuning of MIVEC and the fueling and ignition maps, a fairly stock IX should see decent performance benefits from the aforementioned cams with minimal compromise in driveability. The results probably won't be as dramatic as the AMS test (what everyone has stuck in their heads), but a marked improvement should be attainable.
Dec 18, 2008, 09:26 PM
#3
I wont suggest cams on a IX smaller than the Kelford C cam (the ones you mentioned) or GSC S2s. The FP4Rs have powered some really fast stock turbo cars (search for the user "Fathouse").
However coming to terms with the original question overcamming any car is possible. Its all relative to headflow as Ted pointed out. I would suggest spending some time with the MIVEC, making sure you dont have any boost leaks, all the normal stuff. Its about combination and follow through...you'll get it
However coming to terms with the original question overcamming any car is possible. Its all relative to headflow as Ted pointed out. I would suggest spending some time with the MIVEC, making sure you dont have any boost leaks, all the normal stuff. Its about combination and follow through...you'll get it
Dec 19, 2008, 04:43 AM
#4
Thanks for the insight thus far guys!
I'm toying with 3 options right now:
1. Leave the FP4R's in.
2. Swap the stock cams back in.
3. Replace FP4R's with a less aggressive cam.
I did a boost leak check after I installed my FMIC (about a month ago) and all was well. The cams were installed back in September so they are not a recent mod. My car is still definitely making good power, it just didn't show any gains with the addition of cams. My stock FMIC seemed to be heat-soaking pretty badly so maybe with the addition of the larger FMIC (Perrin) the gains will become more apparent as I'm able to flow more air in a more efficient manner. Regarding the AMS cam shootout, since that was performed on a VIII with built engine and large turbo I never used it as much of a reference other than it being apparent which cam manufacturers make a quality product and which do not.
I'm toying with 3 options right now:
1. Leave the FP4R's in.
2. Swap the stock cams back in.
3. Replace FP4R's with a less aggressive cam.
I did a boost leak check after I installed my FMIC (about a month ago) and all was well. The cams were installed back in September so they are not a recent mod. My car is still definitely making good power, it just didn't show any gains with the addition of cams. My stock FMIC seemed to be heat-soaking pretty badly so maybe with the addition of the larger FMIC (Perrin) the gains will become more apparent as I'm able to flow more air in a more efficient manner. Regarding the AMS cam shootout, since that was performed on a VIII with built engine and large turbo I never used it as much of a reference other than it being apparent which cam manufacturers make a quality product and which do not.
Last edited by Kracka; Dec 19, 2008 at 04:46 AM.
Dec 19, 2008, 06:14 AM
#5
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Did you install a set of springs when you put the cams in? Second how much tuning has been done..
The 4r's on paper look pretty good, its a larger cam than our S1 and a touch smaller than our S2. I would more than likely say it has to be on an upgraded springs.. Over time the stock springs will get some fatigue in them and just can’t handle an upgrade cam... Running to light of a valve spring can have two effects on power, one you can have a valve that wont stay closed all the way or bounce on the seat; especially at higher boost. Two you can get a lot of phantom knock which will pull timing... Valve springs are pretty key with the aggression of some higher horsepower cams and making power.
As far as to aggressive of a cam, you can have many ill effects.. I don't really have the time to write a novel about it but yes you can go to aggressive in many different ways. The most important thing to worry about is RPM range, flow of the head, Engine displacement, and turbo size and efficiency, and matching a cam to a spring...
The 4r's on paper look pretty good, its a larger cam than our S1 and a touch smaller than our S2. I would more than likely say it has to be on an upgraded springs.. Over time the stock springs will get some fatigue in them and just can’t handle an upgrade cam... Running to light of a valve spring can have two effects on power, one you can have a valve that wont stay closed all the way or bounce on the seat; especially at higher boost. Two you can get a lot of phantom knock which will pull timing... Valve springs are pretty key with the aggression of some higher horsepower cams and making power.
As far as to aggressive of a cam, you can have many ill effects.. I don't really have the time to write a novel about it but yes you can go to aggressive in many different ways. The most important thing to worry about is RPM range, flow of the head, Engine displacement, and turbo size and efficiency, and matching a cam to a spring...
Dec 19, 2008, 06:44 AM
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As far as to aggressive of a cam, you can have many ill effects.. I don't really have the time to write a novel about it but yes you can go to aggressive in many different ways. The most important thing to worry about is RPM range, flow of the head, Engine displacement, and turbo size and efficiency, and matching a cam to a spring...
Dec 19, 2008, 07:05 AM
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I'm the friend Kracka mentions with the Kelfords...
So far the cams have been a huge disappointment. Kracka and I both were tuned for the addition of injectors and cams on the same day by the same person and we made within 1 hp and 3 tq of each other. As Kracka mentioned our cars are very similarly modified with the only real difference being the brand of a few of our parts.
Kracka's numbers and power curve were nearly identical to his pre-cam and injector numbers effectively meaning that the cams provided no real increase in power (peak and under the curve) for him and most likely did not add anything for me (I had not been dyno'd or tuned prior).
What the cams did for me was add starting issues when the coolant temp is at 130° F +/- 20° F, idling issues, phantom knock at throttle tip-in when between 3,000 and 3,500 RPM, low speed drivability issues, and recently my AFR's at idle have been bouncing between 19.0:1 and 13.0:1—nearly stalling at the lean end and revving up above 1,000 RPM on the rich end.
The question in my mind is; why aren’t we making any power on the cams? Is it not possible to do so on these cams with a stock turbo and stock head? Are they ‘too aggressive’ for our relatively mild set-ups?
At this point, I’d rather switch back to stock cams than spend the money on new valve springs considering this could only potentially be an issue.
Are we missing something?
For reference, some dyno graphs. After these we pulled some timing out of the upper load/RPM ranges due to knock I was seeing on the street but not on the dyno and I made just over 350 hp/tq on a Dynojet. Since installing a FMIC we added the timing back in and have not seen any knock.
So far the cams have been a huge disappointment. Kracka and I both were tuned for the addition of injectors and cams on the same day by the same person and we made within 1 hp and 3 tq of each other. As Kracka mentioned our cars are very similarly modified with the only real difference being the brand of a few of our parts.
Kracka's numbers and power curve were nearly identical to his pre-cam and injector numbers effectively meaning that the cams provided no real increase in power (peak and under the curve) for him and most likely did not add anything for me (I had not been dyno'd or tuned prior).
What the cams did for me was add starting issues when the coolant temp is at 130° F +/- 20° F, idling issues, phantom knock at throttle tip-in when between 3,000 and 3,500 RPM, low speed drivability issues, and recently my AFR's at idle have been bouncing between 19.0:1 and 13.0:1—nearly stalling at the lean end and revving up above 1,000 RPM on the rich end.
The question in my mind is; why aren’t we making any power on the cams? Is it not possible to do so on these cams with a stock turbo and stock head? Are they ‘too aggressive’ for our relatively mild set-ups?
At this point, I’d rather switch back to stock cams than spend the money on new valve springs considering this could only potentially be an issue.
Are we missing something?
For reference, some dyno graphs. After these we pulled some timing out of the upper load/RPM ranges due to knock I was seeing on the street but not on the dyno and I made just over 350 hp/tq on a Dynojet. Since installing a FMIC we added the timing back in and have not seen any knock.
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Dec 19, 2008, 07:24 AM
#9
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Shane from DB Performance in Rogers MN (www.dbptuning.com).
He's been tuning 4G63's for years and is quite experienced with MIVEC.
He's been tuning 4G63's for years and is quite experienced with MIVEC.
Dec 19, 2008, 07:26 AM
#10
I'm not saying that is the sole cause of your ills, but the factory springs are inadequate for these cams.
Dec 19, 2008, 07:37 AM
#12
Forced Performance claims the FP4R's are safe to rev out to 8k RPM with the stock valve springs which is why I did not upgrade springs. Kelford also told me directly that upgraded valve springs are not required for the IX 272's revving to the stock limiter which is why Zac (hellomynameis) did not upgrade.
Dec 19, 2008, 07:40 AM
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That being said, my strong HP taper in the upper RPM's could very well be caused by the issues Greg brought up. The car felt like it wanted more timing up there but it just wouldn't take it without knocking. Kracka's car has a better power curve in the upper RPM's but he's also able to hold more boost up top with his GM BCS...I'm just running a Joe P manual boost controller but will be switching to GM BCS within the next few months.
Dec 19, 2008, 08:14 AM
#14
Zac, my car made the most power tapering boost down similar to how yours was so I don't feel my ability to hold power better has to do with boost. After over-laying my dyno charts, with the addition of cams and GM BCS, my spool was no sooner or later than with stock cams and a MBC and power held up top was nearly identical. With the recent addition of the FMIC I'm hoping I'll be able to make even more power up top since I can run higher boost on the same timing (or run the same tapering boost with more timing).
Last edited by Kracka; Dec 19, 2008 at 08:17 AM.
Dec 19, 2008, 08:19 AM
#15
Quote from FP's website:
"The grind [referring to IX 4R cams] can be safely operated beyond the stock redline to 8krpm with the stock springs in place"
This is seriously one of the reasons I went for these cams because I wanted it to be a simple, reliable, bolt-on affair.
"The grind [referring to IX 4R cams] can be safely operated beyond the stock redline to 8krpm with the stock springs in place"
This is seriously one of the reasons I went for these cams because I wanted it to be a simple, reliable, bolt-on affair.
Last edited by Kracka; Dec 19, 2008 at 08:40 AM.