When are cams too aggressive for a setup?
I helped install both of these sets of cams, and was there when the they were on the dyno for final tuning. I think one important element that has been left out is the FMIC. Both of these cars went to cams before upgrading their FMIC from the stock unit. It seemed insane to me that neither of them made any more power than before but when out for test drives, they 'seemed' to feel stronger on the street. On the dyno, both cars seemed to knock up top, preventing them from running much timing and thus more power. I'm not the tuner, but that is what I saw.
Furthermore, both of these cars now have upgraded to Perrin FMICs and to me, now seem to have a good combo and should get back on the dyno for further tuning/testing. Both cars (from what I hear) have been tweaked on the street to run more boost or more timing up top and both are knock free in doing so.
Furthermore, both of these cars now have upgraded to Perrin FMICs and to me, now seem to have a good combo and should get back on the dyno for further tuning/testing. Both cars (from what I hear) have been tweaked on the street to run more boost or more timing up top and both are knock free in doing so.
316whp on a dyno dynamics with no correction factor in sight leads me to believe there are tuning issues, experience aside. What does a stock Evo IX make on this dyno, was the correction factor on before AND after, either time, was it set the same if it was on? Is this shootout mode?
If you can get it too me, I'd like to take a look at the map. If you have logs even better. I can personally vouch for any of these cams being a vast improvement. I can tell from the dyno pull and the amount of power it drops as fast as it does that valvesprings or severe boost taper are really starting to make issues at the rpm it should be making the most power.
Aaron
If you can get it too me, I'd like to take a look at the map. If you have logs even better. I can personally vouch for any of these cams being a vast improvement. I can tell from the dyno pull and the amount of power it drops as fast as it does that valvesprings or severe boost taper are really starting to make issues at the rpm it should be making the most power.
Aaron
No correction factors used on this dyno, a stock IX makes around 220whp on this dyno. No shootout mode. The tuning issue was with knock up top, the cars simply would not run the amount of timing needed to make decent power.
Dropping power up top on the stock turbo seems to be the norm on Dyno Dynamics with the stock turbo. Not sure if it loads the car differently up there or what, but boost taper or not it's fairly common from what I see out there (at DB and other sources on the net).
One interesting point was when boost was left up to eliminate taper on Kracka's car (using GM BCS) but timing was way low, and it was down on power. Shane turned the boost down up top, and put in more timing. The car made the same amount of power. Now, with Kracka's new FMIC, we have the left the timing be and turned the boost back up without any additional knock.
Dropping power up top on the stock turbo seems to be the norm on Dyno Dynamics with the stock turbo. Not sure if it loads the car differently up there or what, but boost taper or not it's fairly common from what I see out there (at DB and other sources on the net).
One interesting point was when boost was left up to eliminate taper on Kracka's car (using GM BCS) but timing was way low, and it was down on power. Shane turned the boost down up top, and put in more timing. The car made the same amount of power. Now, with Kracka's new FMIC, we have the left the timing be and turned the boost back up without any additional knock.
Last edited by scheides; Dec 19, 2008 at 08:48 AM.
No correction factors used on this dyno, a stock IX makes around 220whp on this dyno. No shootout mode. The tuning issue was with knock up top, the cars simply would not run the amount of timing needed to make decent power.
Dropping power up top on the stock turbo seems to be the norm on Dyno Dynamics with the stock turbo. Not sure if it loads the car differently up there or what, but boost taper or not it's fairly common from what I see out there (at DB and other sources on the net).
One interesting point was when boost was left up to eliminate taper on Kracka's car (using GM BCS) but timing was way low, and it was down on power. Shane turned the boost down up top, and put in more timing. The car made the same amount of power. Now, with Kracka's new FMIC, we have the left the timing be and turned the boost back up without any additional knock.
Dropping power up top on the stock turbo seems to be the norm on Dyno Dynamics with the stock turbo. Not sure if it loads the car differently up there or what, but boost taper or not it's fairly common from what I see out there (at DB and other sources on the net).
One interesting point was when boost was left up to eliminate taper on Kracka's car (using GM BCS) but timing was way low, and it was down on power. Shane turned the boost down up top, and put in more timing. The car made the same amount of power. Now, with Kracka's new FMIC, we have the left the timing be and turned the boost back up without any additional knock.
Both also have SS o2 housings and ported exhaust manifolds. The power is impressive, but the fact of the matter is that w/o the cams and FMIC and GM BCS, Kracka's car made a solid 310whp on the same dyno. On his car 'low boost' up top I believe it tapered to ~19psi. On high, it holds 22-23 at 7000rpms (if I remember right).
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.
All those issues you are having are consistent w/ injectors that haven't been scaled correctly and have incorrect voltage latencies. What size/type injectors are you running?
So you need to change cam chacteristcs, why not try cam gears and set them for more low end..IE, + intake cam degrees and + ex cam degrees... this will move the power band. Unless your floating valves and you will know- springs wont change anything. yes you can overcam a car, motor etc...havent seen or heard that with the k272 yet.., my thoughts have laways been that with a cam that big that you would bleed off alot of low end...most dont seem to mind it though..
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From: Mitchigan
evo cam test
if someone didn't post it already
https://www.evolutionm.net/forums/ev...-cam-test.html
if someone didn't post it alreadyhttps://www.evolutionm.net/forums/ev...-cam-test.html