Which(size & brand) cams are you running with your ported head?
Apr 9, 2007 | 01:55 PM
#17
The effects of certain modifications on my car were as follows:
1.) Stock head, Stock Intake, 50 trim - earliest spoolup, good initial torque, not the greatest topend
2.) Stock head, AMS VSR intake, 65mm TB, 50 trim - spools ~200 RPM later than stock intake/head, makes about the same initial torque, added anywhere from 20-30 wtq across the power band, added ~35whp @ 7000 rpm
3.) Ported head, AMS VSR intake, 65mm TB, 50 trim - spools ~200 RPM later than the stock intake/head, makes 20 ft-lbs less torque intially than the VSR intake with stock head, starts making the same power at ~5000 RPM and then ends up making 10 whp more at 7000 RPM. It's interesting to note that with this combo on my car peak torque is at 7000 RPM.
I actually did not want to go with the ported head, but the car developed 2 bad valves on the original head, so I said f*ck it. One of the few mods that I'm really not sure how I feel about. On the one hand it sucks to lose that much torque down low, but on the other hand with that much power on tap, the smaller initial 'hit' isn't such a bad thing - and when I'm road racing it, I try to never let the RPM drop below 4000-4500 anyways...
I have my idle target set to 1100 RPM. The actual idle generally varies from 900 - 1300 RPM. With the larger injectors (780cc) it's not as stable as I'd like it to be ... I think I can get it to idle 100% with some more tweaking. Right now, though it'll catch an occasional rich spike, which has a tendency to start making the idle fluctuate, which on occasion will stall the car. Also, with the larger TB, Exedy twin metallic and the larger injectors, it is very difficult to drive the car in a stop-n-go situation. I've learned how to do it, but so far everyone that has tried to drive the car has stalled it on the first try and then some.
l8r)
1.) Stock head, Stock Intake, 50 trim - earliest spoolup, good initial torque, not the greatest topend
2.) Stock head, AMS VSR intake, 65mm TB, 50 trim - spools ~200 RPM later than stock intake/head, makes about the same initial torque, added anywhere from 20-30 wtq across the power band, added ~35whp @ 7000 rpm
3.) Ported head, AMS VSR intake, 65mm TB, 50 trim - spools ~200 RPM later than the stock intake/head, makes 20 ft-lbs less torque intially than the VSR intake with stock head, starts making the same power at ~5000 RPM and then ends up making 10 whp more at 7000 RPM. It's interesting to note that with this combo on my car peak torque is at 7000 RPM.
I actually did not want to go with the ported head, but the car developed 2 bad valves on the original head, so I said f*ck it. One of the few mods that I'm really not sure how I feel about. On the one hand it sucks to lose that much torque down low, but on the other hand with that much power on tap, the smaller initial 'hit' isn't such a bad thing - and when I'm road racing it, I try to never let the RPM drop below 4000-4500 anyways...
I have my idle target set to 1100 RPM. The actual idle generally varies from 900 - 1300 RPM. With the larger injectors (780cc) it's not as stable as I'd like it to be ... I think I can get it to idle 100% with some more tweaking. Right now, though it'll catch an occasional rich spike, which has a tendency to start making the idle fluctuate, which on occasion will stall the car. Also, with the larger TB, Exedy twin metallic and the larger injectors, it is very difficult to drive the car in a stop-n-go situation. I've learned how to do it, but so far everyone that has tried to drive the car has stalled it on the first try and then some.
l8r)
Was this on pump gas? If so I would think that adding some alky would gain you back your lost tq and maybe spool. I least I hope so as my ported head 50 trim 280 set up will be on the road next week. I'm also running meth.
Apr 9, 2007 | 06:38 PM
#18
1997cc FTW!!! 
Honestly, for what I'm doing with it there is no logical reason to stick with a 2.0 ... I just like the way it sounds when it's revved out past 8500 rpm. Actually after today's dyno session at AMS, I consider the power mods to be officially finished. I finally have the powerband and torque curve that I want and I think we've worked out the last few remaining gremlins with the tune - at least for the next week or so (until the next problem pops up) ...
From a performance/longevity/driveability standpoint the 2.3 would be the better choice.
l8r)
Honestly, for what I'm doing with it there is no logical reason to stick with a 2.0 ... I just like the way it sounds when it's revved out past 8500 rpm. Actually after today's dyno session at AMS, I consider the power mods to be officially finished. I finally have the powerband and torque curve that I want and I think we've worked out the last few remaining gremlins with the tune - at least for the next week or so (until the next problem pops up) ...
From a performance/longevity/driveability standpoint the 2.3 would be the better choice.
l8r)
Last edited by Ludikraut; Apr 9, 2007 at 07:43 PM. Reason: late breaking news, lol
Apr 9, 2007 | 06:44 PM
#19
Meth will gain you quite a bit over a straight pump gas tune. You'll probably end up making between 450 and 500whp. However, (assuming an MBC, which is what I'm currently running) the difference between the spoolup and initial torque characteristics shouldn't really change. I would still expect a stock head to give you more of an initial torque peak, whereas the ported head (again assuming it is ported the same way as mine - God knows the odds on that are pretty slim) will have less of an initial torque peak.
l8r)
l8r)
Apr 10, 2007 | 06:34 AM
#20
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From: Columbus, Ohio
Apr 10, 2007 | 08:56 AM
#23
IMO, it makes little sense to go through the trouble and expense to swap in a ported head and upgraded valvetrain, only to end up running HKS cams. More power has been left on the table than gained.
Apr 10, 2007 | 09:11 AM
#24
Even with stock ECU? I plan on getting some high lift cams but only after I get an AEM. Not familier with ALL the cams out there but I've seen where people have had issues with Revolvers and stock ecu.
Apr 10, 2007 | 09:19 AM
#25
Even with the stock ECU.
Cams with a better ramp profile and more lift will deliver a significant improvement in spool and torque characteristics, and will improve power so long as the turbo is up to it.
Cams with a better ramp profile and more lift will deliver a significant improvement in spool and torque characteristics, and will improve power so long as the turbo is up to it.
Apr 10, 2007 | 10:40 AM
#26
Ted, would you care to elaborate on that? Which cams do you think could provide more punch over the HKS 280s without losing any of the topend? What kind of torque difference would you expect to see on a pump gas tune?
l8r)
l8r)
Apr 10, 2007 | 11:30 AM
#27
Ludi anything JUN offers would probably be a candidate, GSC S2's, the Tomei Cams aswell, the smaller durations of each of these cams might give up a tad bit of topend to the 280s but I doubt it, they all run a good bunch more lift I believe.
Not Ted
Scorke
Not Ted
Scorke
Apr 10, 2007 | 12:21 PM
#28
the lift should help with the horsepower number at the corresponding rpm area (corresponding to the degree position of increased lift) but would that help for extending the power curve in any one direction?
i'm thinking not and that makes me want to say be careful and consider that. you don't wanna get all this work done and just have a super high spike and taper down to similar powerlevels or not extend to where you need it (that's more relavent here) although the head work will always shift things up in rpm.
i'm thinking not and that makes me want to say be careful and consider that. you don't wanna get all this work done and just have a super high spike and taper down to similar powerlevels or not extend to where you need it (that's more relavent here) although the head work will always shift things up in rpm.
Apr 10, 2007 | 01:26 PM
#30
Duration at 1mm is what's important, as well as ramp shape, and of course a ported head's ability to make use of more lift. It just doesn't make sense to me to throw all that money after a head, and allow the cams to be the limiting factor. The HKS cams are convenience grinds for stock heads and valvetrains, and not much else. Better grinds will outperform them 10 times out of 10.