Got a '99 S-truck w/LN2, lookin' to get a long-tube header for it soon (Hopefully) to help pump-up the low-end torque. Saw the LDA/LSA for the '92-'97 & '98-'05 cams, figure with the header helping to scavenge the gases that the wider separation of of a '96-'97 cam would be the way to go to maximize the cylinder pressure in my search to improve efficiency. Any help?
Go beyond the "bolt-on".
I'd experiment with the intake manifold before messing with the exhaust side or cams.
2002 Cavalier 2200 5spd
Solid Snake wrote:I'd experiment with the intake manifold before messing with the exhaust side or cams.
Interesting suggestion... But how (For cheap!)? The only other intake commonly available is the one used on the J-car, and that has shorter runners.
Go beyond the "bolt-on".
A MP62?
A steped header may help, but what kind of LSA is it dealing with? ext port valume? intake?
lots of things go in to this.
Chris
'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08
Are the S-10 and J-body cams the same? If the S-10 produces a better torque curve it could be a nice JY upgrade. Has anyone looked into it?
The Outlaw
98 Pontiac Sunfire (Christine)
2200 5spd
Red with Black racing stripes.
Don't let the punks get to you. If they can't say anything helpful its because they probably
have VERY LITTLE IF ANY MECHANICAL SKILLS . Talking crap is just their way of hiding that
fact. They figure the more crap they say the less likley anyone will know how dumb they are.
the outlaw wrote:Are the S-10 and J-body cams the same? If the S-10 produces a better torque curve it could be a nice JY upgrade. Has anyone looked into it?
As far as my research has shown me, the only real difference between the S-truck & J-car trim LN2s is the intake & exhaust manifolds... And the coolant inlets & outlets. So, no difference in cam there.
I've thought of a stepped header, and thought of having one made that incorporates all special li'l "tricks" I've seen used in header design (Tri-Y, merge-style collectors, anti-reversion cones...). But no one's willing to go that far to make a header for an app they're unfamiliar with (Odd, I know...).
My best bet is one that was made as a prototype by CIA (Not
the CIA) that uses 1-3/8" x 22" primaries. It really helps bump-up low-end torque, but looking at the LSA between the pre-'98 & post-'97 cams, I can see a large amount of cylinder-pressure costing overlap. Now, I know that overlap helps pull fresh charge into the cylinder while the exhaust system (Header or manifold) is scavenging the spent, but I can't help think that maybe if the intake's already sonically tuned as good as it'll get for a realistically seen on-the-street RPM-range that if a header with nice,
long tubes, combined with a increased LSA cam will really help punch-up the low-end... Then I can just reprogram the shift-points to be a li'l sooner, maybe add an overdrive tailshaft w/ bigger FDR, to take advantage of the increase in low-end torque had by increased cylinder pressure (And a cleaner charge to boot!) and really improve fuel-efficiency of my truck without resorting to band-aid add-ons like "tailgate net" (Sorry Mythbusters, but I need a hard one daily... Uh, you know what I mean.).
Go beyond the "bolt-on".
Just checked them on autozone and yes the cams are the same. So that sucks.
The Outlaw
98 Pontiac Sunfire (Christine)
2200 5spd
Red with Black racing stripes.
Don't let the punks get to you. If they can't say anything helpful its because they probably
have VERY LITTLE IF ANY MECHANICAL SKILLS . Talking crap is just their way of hiding that
fact. They figure the more crap they say the less likley anyone will know how dumb they are.
Still using 4:10 rear gears? Not a good ending for a low end cam. Simple trick is to adjust cam timing to bias torque peak in direction of most frequent rpm use. Also, watch overlap numbers. Not whole story, for sure. Ramp rates are a big part of the game. Check efficiency ratings for older and newer engines... very close.
I'm following the plan I gave you years ago. Lower final drive plus boost. We'll see how it turns out.
-->Slow
I hear ya, Slow... Gonna keep it in mind. Thanks & good-luck with your efforts.
BTW: You wanna talk efficiency numbers? The '99 gets 20.5mpg on average & the '94 gets 23.5... Trucks are built (Including minor changes I made (Plugs, wires...)) the same way, and the older one does better? Without SMPI & knock-sensor? Someone, please... Help me figure that out!!
Go beyond the "bolt-on".
