I had originally purchased a 109 hyd roller & got stuck with a 112 cam.The car has a Ta61,heads,BG Intercooler,50lbs,5 disc Vigilante etc,etc.Comp Cams said advance it 4 deg & it will fly.I'm skeptical that this will produce the desired "total rpm effect" of the 109.Looks like a mid range/top end trade off for improved bottom end response.It also smells of power losses due to premature exhaust valve opening.Does anyone have any experince with this or similar cam & advancing 4 deg?I think this cam is a generic grind & I got a generic cam grinder answer.Any feedback would be great . Thanks
112 deg Lobe Ctr Split Hyd Roller
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Could probably give a better answer if more is known about the cam specs? Not sure what is meant by "total RPM effect".
A 112 lobe sep. does not sound like it will make a lot of difference depending on the grind. Am going to try out a 112 on a 224/224 Comp grind tonight for the first time. Should give lower cylinder pressure which can allow higher boost w/o detonation. Will see?
Know of a few others that prefer the 112-114 lobe sep in their turbo motors.
A 112 lobe sep. does not sound like it will make a lot of difference depending on the grind. Am going to try out a 112 on a 224/224 Comp grind tonight for the first time. Should give lower cylinder pressure which can allow higher boost w/o detonation. Will see?
Know of a few others that prefer the 112-114 lobe sep in their turbo motors.
Yeah need to know more about the size of cam. Just my $0.02, but I have cyl press traces showing that the exh probably needs help blowing down on a high flow turbo v6, and widening the lobe sep does just that, gets the exh open earlier for a given icl. There should be no downside to that. As for advancing it, that will make a noticeable difference in bottom end on the turbo v6 IME. We've tried it several times now on various combos and it does the same thing each time, namely comes up better and feels a bit more responsive. The tradeoff is probably that you close the int earlier which is not good for top end. It all depends on what your intended rev range is and your converter and all.
FWIW I had a 224/224/110 solid roller in my 274"/GN1's street v6 for starters. Installed well advanced at about 104 icl. With a T76/.81 4 bolt q trim it made 30+ psi boost. It came up very well and was very responsive. Idled at about 17 in Hg, so obviously favorable to the low end. Ran very well, but the combo dictates more rev range, needs to go to about 7200 rpm. Of course if you're only going to rev to say 6200-6300 or so then a 224 range stick is probably plenty.
Fast fwd to recently, put in a new 242/242/114 solid roller, installed on a 110 icl. Along with some much stronger pushrods. This cam gets the intake open in nearly the same place as before, but hangs the int open some 15+ deg longer. Also gets the exh open some 15+ deg earlier, yet still closed by ~ TDC.
Results so far, it went ~ 4 mph faster than before in the 1/8th mile on the 1st pass, through a closed single 3" exh, at 4 psi LESS boost I might add
Now the same turbo only makes 26 psi max. Target for now is 120 mph in the 1/8th and she's getting close already Uncorking the exh and launching harder than a 0 boost, just roll it out 1.65 60' would put it there. The upside to the easy launches has been that the original stock rearend still looks ~ new inside after 15 yrs. No spline twist or damage, no anything. We changed posi clutch disks last week and just put it all back together for now.
Idles at about 12 in Hg, yet drives and idles fine IMO, considering the weekend warrior-type perf level and all. A 242 is maybe larg'ish in the turbo Buick scene I guess, but probably not so big really in the grand scheme of things. Not all radical like I feared it might be. Also still comes up great, the converter stalls to about 3700 and seems to be a great match for the combo. I like it, and obviously the engine does too Note that I also use a little nawzzz assist in 2nd and 3rd gears.
Hope that helps somehow (?). JME and MO.
TurboTR
FWIW I had a 224/224/110 solid roller in my 274"/GN1's street v6 for starters. Installed well advanced at about 104 icl. With a T76/.81 4 bolt q trim it made 30+ psi boost. It came up very well and was very responsive. Idled at about 17 in Hg, so obviously favorable to the low end. Ran very well, but the combo dictates more rev range, needs to go to about 7200 rpm. Of course if you're only going to rev to say 6200-6300 or so then a 224 range stick is probably plenty.
Fast fwd to recently, put in a new 242/242/114 solid roller, installed on a 110 icl. Along with some much stronger pushrods. This cam gets the intake open in nearly the same place as before, but hangs the int open some 15+ deg longer. Also gets the exh open some 15+ deg earlier, yet still closed by ~ TDC.
Results so far, it went ~ 4 mph faster than before in the 1/8th mile on the 1st pass, through a closed single 3" exh, at 4 psi LESS boost I might add
Now the same turbo only makes 26 psi max. Target for now is 120 mph in the 1/8th and she's getting close already Uncorking the exh and launching harder than a 0 boost, just roll it out 1.65 60' would put it there. The upside to the easy launches has been that the original stock rearend still looks ~ new inside after 15 yrs. No spline twist or damage, no anything. We changed posi clutch disks last week and just put it all back together for now.Idles at about 12 in Hg, yet drives and idles fine IMO, considering the weekend warrior-type perf level and all. A 242 is maybe larg'ish in the turbo Buick scene I guess, but probably not so big really in the grand scheme of things. Not all radical like I feared it might be. Also still comes up great, the converter stalls to about 3700 and seems to be a great match for the combo. I like it, and obviously the engine does too
Note that I also use a little nawzzz assist in 2nd and 3rd gears.Hope that helps somehow (?). JME and MO.
TurboTR
Cam Details
Comp Cam 206/206 hyd roller,.496/.496 gross lift,112deg lobe ctr split.The car will be an occasional strip warrior,with an occasional high 10 sec goal,with reality setting in at the mid to low 11 sec level.I'm not convinced that the lobe ctr split is correct for what I'm trying to do.I think a 4 deg cam advance is a bandaid to cover the fact that the vendor bought a bunch of 112's instead of 109's.The customers ordered 109's.I can believe that bumping the boost up may cover the early exh valve event,but I question how the higher turbo air temp out to a stock location BG intercooler helps air density?...just shooting off my mouth
Comp Cam 206/206 hyd roller,.496/.496 gross lift,112deg lobe ctr split.The car will be an occasional strip warrior,with an occasional high 10 sec goal,with reality setting in at the mid to low 11 sec level.I'm not convinced that the lobe ctr split is correct for what I'm trying to do.I think a 4 deg cam advance is a bandaid to cover the fact that the vendor bought a bunch of 112's instead of 109's.The customers ordered 109's.I can believe that bumping the boost up may cover the early exh valve event,but I question how the higher turbo air temp out to a stock location BG intercooler helps air density?...just shooting off my mouth
Re: Cam Details
Not sure the best way to word this, but higher pressure almost always outweighs higher temperature for increasing the charge density.
Even on a nonIC car, increasing the boost pressure will increase the charge density, even with the increased charge temperature. Even if you assume the compression efficiency is dropping, you have to have a pretty big drop to see the charge density fall at a higher pressure.
Toss in the moderating effect of an IC (any IC, even if it is undersized), and you'll find that 99% of the time higher boost = higher charge density.
About your cam, why does the 112 LSA give you the willies over a 109 LSA? I was under the impression (and maybe I'm confused on the point) that maybe a wider LSA was a good thing for a turbo engine, reduced overlap being a plus?
John
Not sure the best way to word this, but higher pressure almost always outweighs higher temperature for increasing the charge density.
Even on a nonIC car, increasing the boost pressure will increase the charge density, even with the increased charge temperature. Even if you assume the compression efficiency is dropping, you have to have a pretty big drop to see the charge density fall at a higher pressure.
Toss in the moderating effect of an IC (any IC, even if it is undersized), and you'll find that 99% of the time higher boost = higher charge density.
About your cam, why does the 112 LSA give you the willies over a 109 LSA? I was under the impression (and maybe I'm confused on the point) that maybe a wider LSA was a good thing for a turbo engine, reduced overlap being a plus?
John
112 LSA
I'm trying to get a perspective for whether or not a 112 Lsa cam with the previously described hardware is as good a fit as a 109 Lsa cam.The car is basically a street car.The original cam that I wanted was 206/206,.446 gross lift,& 109 Lsa billet roller.I think there are are too many things to be considered in a complex discussion with this subject matter.I'm sure that my introduction of the topic did not point the discussion in the desired direction.
I'm trying to get a perspective for whether or not a 112 Lsa cam with the previously described hardware is as good a fit as a 109 Lsa cam.The car is basically a street car.The original cam that I wanted was 206/206,.446 gross lift,& 109 Lsa billet roller.I think there are are too many things to be considered in a complex discussion with this subject matter.I'm sure that my introduction of the topic did not point the discussion in the desired direction.
Well a 206 is tiny really, almost a stocker. IMO a wider lobe sep is probably better, though maybe not just for reducing overlap since the small 206 has low overlap to begin with really. It's probably better at wot to open the exh valve a bit earlier. I'd run it. Your task then is to decide what icl to put it on. Depends on your converter and combo and all. If it needs help coming up and you don't plan to spin it very high them maybe some advance, like a 106 icl. If it comes up ok already them maybe want to try and emphasize some top range so like a 110 icl. Just some thoughts. With a 3 keyway timing gear set you'll have the options, plus offset keys are also available.
Or maybe I'm just confused with what you're saying here, what is the lobe sep of this cam, 112, or?
TurboTR
Or maybe I'm just confused with what you're saying here, what is the lobe sep of this cam, 112, or?
TurboTR
112 LSA cam
The cam is 112 LSA.The turbo comes up slow with this cam,so if forced to use this cam,it will require about a 108 icl.This still strikes me like a bandaid since the 206/206 has steep ramps & little overlap.This is a street car that will see some passes hopefully in the low elevens & maybe even a high 10.It has a Vigilante 5 disc (3200 rpm stall 5psi) & a Bowling Green stock location intercooler.Also has a Ta61 & head work.I think the cam won't help the cars response on the street which is the major concern.
The cam is 112 LSA.The turbo comes up slow with this cam,so if forced to use this cam,it will require about a 108 icl.This still strikes me like a bandaid since the 206/206 has steep ramps & little overlap.This is a street car that will see some passes hopefully in the low elevens & maybe even a high 10.It has a Vigilante 5 disc (3200 rpm stall 5psi) & a Bowling Green stock location intercooler.Also has a Ta61 & head work.I think the cam won't help the cars response on the street which is the major concern.
REDS HOT AIR
Buick Tweaker
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I too agree that if your looking for more streetability and resonce out of the cam advace It a few degrees and see the responce improvement you get.
I have found comp cams to be very lazy down low if you set them up as the cam card recomends and find then alot more responsive advanced.
I have found comp cams to be very lazy down low if you set them up as the cam card recomends and find then alot more responsive advanced.
