Any of you guys use the 98 Cobra cams with a centri?
- Thread starter SIZEMOREMK
- Start date
RacerX
New England Marauder Member
This is an old setup I had. Stock vs. 98 Cobra intake cams (straight up, not advanced) and a NAZ PSRI. Low end dropped, but, power band was extended quite a bit. Reinstalled the long runner intake (after Todd's recommendation) and got my low end back without sacrificing top end gains. If I had advanced these, there would have been slightly better improvements.
SIZEMOREMK
Junior Member
Man, I'm so confused...
Several places I have seen said that the LCs were 114 for intake and exhaust for both the the 03/04 and 96/98??
I seen your recommendation for installing these 108/110 and thought maybe that was advancing the intake 6* and exhaust 4*...
As for the big cost, what other than the cost of 2 more intake cams is required? Assuming adjustable cams gears and crank sprockets would be used already?
Or are you saying that the gains from using the intakes as exhasut cams would not be woth the cost of the 2 extra intake cams?
Thank ya sir! I appreciate the guidance!
SIZEMOREMK
Junior Member
Just to be clear here, what I'm after is not 1/4 times or peak HP, the interest is in more low-mid for better throttle response and seat of the pants gain when the mood strikes. I rarely get to the track, and when I do its only 1/8th mile.
In the past, I had a 3.8 V6 SC Thunderchicken that I did some pretty extensive work to, aftermarket upgraded eaton M90 @12+ psi, alky inj, cam, head work to include bigger valves and port work, and a AOD with wide ratio gearset, very mild non-locking converter, and stock 3.27 gears. This car had more down low and mid than my Marauder does and it was a V6; of course the Marauder makes alot more up top.
I bought my Marauder with the centri, not realizing how drastic the difference is between a centri and roots blowers; knew there would be a difference, but not so much. My prefrence if money were no object would be a twin-screw blower. That is not in the cards at this time, plus I'm not sure I would want to try a whipple or kenne bell on my bottom end (an MMR 600). I'm not interested in an eaton, I've had them and too much heat for daily driving. Next big project on down the road will be big block or whipple, might even be in a different car?
So without the PD option in the near term, I am trying to figure out how to get some more torque and better mid-range throttle response so I don't have to rev all the way up to get pushed back it the seat.
I would probably give up 20 or so peak HP for significant increase in area under the torque curve before 4500K RPM or so.
As for spinning the blower faster, I was thinking if could shape the power curve to hit harder eariler and peak closer to 5800ish RPM, I could pulley the blower as fast specs allow for a 5800Kish shift and call it a day, don't really care about the PSI. I imagine the PSI will drop a few lbs if the cams allow some more air in anyways.
So what I am after is info on whether these 98 cams in whatever combination would support such a goal.
Actually, this post by NA SVT on an other form shows the change in shape I am after, I'm curious how this would apply to a cenri car?
http://www.svtperformance.com/forum...3-04-heads&p=12636362&viewfull=1#post12636362
Thanks guys!
In the past, I had a 3.8 V6 SC Thunderchicken that I did some pretty extensive work to, aftermarket upgraded eaton M90 @12+ psi, alky inj, cam, head work to include bigger valves and port work, and a AOD with wide ratio gearset, very mild non-locking converter, and stock 3.27 gears. This car had more down low and mid than my Marauder does and it was a V6; of course the Marauder makes alot more up top.
I bought my Marauder with the centri, not realizing how drastic the difference is between a centri and roots blowers; knew there would be a difference, but not so much. My prefrence if money were no object would be a twin-screw blower. That is not in the cards at this time, plus I'm not sure I would want to try a whipple or kenne bell on my bottom end (an MMR 600). I'm not interested in an eaton, I've had them and too much heat for daily driving. Next big project on down the road will be big block or whipple, might even be in a different car?
So without the PD option in the near term, I am trying to figure out how to get some more torque and better mid-range throttle response so I don't have to rev all the way up to get pushed back it the seat.
I would probably give up 20 or so peak HP for significant increase in area under the torque curve before 4500K RPM or so.
As for spinning the blower faster, I was thinking if could shape the power curve to hit harder eariler and peak closer to 5800ish RPM, I could pulley the blower as fast specs allow for a 5800Kish shift and call it a day, don't really care about the PSI. I imagine the PSI will drop a few lbs if the cams allow some more air in anyways.
So what I am after is info on whether these 98 cams in whatever combination would support such a goal.
Actually, this post by NA SVT on an other form shows the change in shape I am after, I'm curious how this would apply to a cenri car?
http://www.svtperformance.com/forum...3-04-heads&p=12636362&viewfull=1#post12636362
Thanks guys!
sailsmen
Supporting Member
From an old post;
"Timeslipe data from a Vortec and Trilogy. Same gears, tires, exhaust, TC, Eaton 12.5psi and Vortec 10psi. Can you pick which is which?
1.704 5.089 7.942 85.53 10.438 12.554 106.67
1.741 5.096 7.924 86.4 10.399 12.501 107.33
1.702 5.046 7.886 85.7 10.383 12.511 105.89
1.691 5.025 7.852 86.34 10.328 12.426 107.56
1.745 5.096 7.883 87.13 10.329 12.391 109.4
1.748 5.114 7.907 86.9 10.358 12.427 109.03
1.72 5.047 7.822 88.15 10.272 12.333 109.52
1.716 5.019 7.79 87.37 10.237 12.3 109.38
1.744 5.098 7.894 86.79 10.355 12.431 108.69
1.69 5.221 8.051 86.58 10.514 12.921 108.65
Stock Trilogy 388RWHP/369RWTQ
Stock + the Trilogy and + the Vortec both ran 12.9-13.3 depending on temps. As far as the Trilogy providing more low end Torque the 60' times show no descernable difference.
Can you tell which is which? The kits are so close in any given race it will come down to the driver every time.
I cannot tell which is my Cent and which is the Eaton. What this proves it that from a dead stop by the 60' there is no measurable difference. Maybe there is a difference for the first 20'?"
ps I owned a Thunderbird S/C, great car.
"Timeslipe data from a Vortec and Trilogy. Same gears, tires, exhaust, TC, Eaton 12.5psi and Vortec 10psi. Can you pick which is which?
1.704 5.089 7.942 85.53 10.438 12.554 106.67
1.741 5.096 7.924 86.4 10.399 12.501 107.33
1.702 5.046 7.886 85.7 10.383 12.511 105.89
1.691 5.025 7.852 86.34 10.328 12.426 107.56
1.745 5.096 7.883 87.13 10.329 12.391 109.4
1.748 5.114 7.907 86.9 10.358 12.427 109.03
1.72 5.047 7.822 88.15 10.272 12.333 109.52
1.716 5.019 7.79 87.37 10.237 12.3 109.38
1.744 5.098 7.894 86.79 10.355 12.431 108.69
1.69 5.221 8.051 86.58 10.514 12.921 108.65
Stock Trilogy 388RWHP/369RWTQ
Stock + the Trilogy and + the Vortec both ran 12.9-13.3 depending on temps. As far as the Trilogy providing more low end Torque the 60' times show no descernable difference.
Can you tell which is which? The kits are so close in any given race it will come down to the driver every time.
I cannot tell which is my Cent and which is the Eaton. What this proves it that from a dead stop by the 60' there is no measurable difference. Maybe there is a difference for the first 20'?"
ps I owned a Thunderbird S/C, great car.
RacerX
New England Marauder Member
Being assembly line built, the exact lobe centers, separation angles etc. are going to be different on every single mod engine by X degrees. Even bank to bank. You can install the 98 intakes "straight up", without degreeing. This isn't the right way to do it if you want the full performance gain out of them. You need to get Cloyes adjustable cam gears and then degree everything. I doubt you can use intakes in place of the exhaust cams. I'm pretty sure that would cause major PTV issues. Not to mention, getting exhaust out of the cylinder isn't the issue. Filling the cylinder with more air and fuel is.
SIZEMOREMK
Junior Member
I do not see why the intake cams on the exhaust side would not work if properly degreed?
I'm not sure which adjustable cams to use, I've seen where the cloyes are popular, and the modular performance ones might also be gooduns?
If I end up messing with the cams, they will indeed get the appropriate adjustable gears/sprockets in order to degree and/or advance them properly.
It is my understanding that some cams had keyways and some didn't depending on year? I've not been in the 4.6 before, so I'm not sure of all of the details quite yet; I'm not sure if having the key will matter or not witht he adjustable gears and such.
But i do see where the crower cam above looks to be the same cams for intake/exh and both specs are pretty close to using two 98 cobra intakes.
Edited: I went ahead and called Crower, they did indicate that the intake and exhast cams were the same cams.
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