Alternating Roller Rocker Ratios
Joined: Nov 2001
Posts: 10,023
Likes: 6
From: LT1 land...the "409" of the 90s!
It LIKES .608 lift and picked up TQ through the entire range. I've done tons of R&D on this and the LT1 loves exhaust. I picked up over a tenth and 2 mph going from 1.6s to 1.7s. BUT, now that Comp Cams makes 1.8 rockers that fit the LT1, the playing field will be changed again.
I know plenty of guys that run GM847s on stock bottom end LT1s and that's ~.595 on the exhaust end. With 1.8s on a stock cam the lift will be .536/.551so no worries on the piston-to-valve clearance. That's awesome and only have to remove the valve covers to do it and not spend an entire weekend in the garage.
I know plenty of guys that run GM847s on stock bottom end LT1s and that's ~.595 on the exhaust end. With 1.8s on a stock cam the lift will be .536/.551so no worries on the piston-to-valve clearance. That's awesome and only have to remove the valve covers to do it and not spend an entire weekend in the garage.
^ Or you could have just gotten a cam ground that way to begin with. I agree with who ever said it before. Alternating rocker ratios is simply a tuning tool or a patch for a previous mistake.
If it adds power in itself, then how is it ONLY a tuning tool? Obviously if it makes you lose power or retain the same then it's pointless, but if you found it to work would you take them out? I wouldn't.
They actually do this same thing in the 3800 Series II motors... the N/A ones.
They actually do this same thing in the 3800 Series II motors... the N/A ones.
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Verdad Gallardo Joined: Nov 2001
Posts: 10,023
Likes: 6
From: LT1 land...the "409" of the 90s!
When I can I have it cut into the shaft along with the correct ICL.
NASCAR is running 2.0-2.3 ratio's. they don not have to move the lifter as far in the bore
NASCAR is running 2.0-2.3 ratio's. they don not have to move the lifter as far in the bore
Yeah, if I wasn't running bolt ons only. So, a custom grind cam is out of the
question. Alternating rockers is a method to obtain more horsepower, especially for us bolt on guys who are looking for every .0002 horsepower we can find.
Exactly. I believe in getting every single hp I can out of the car. Going bolt ons is easy on the budget, allows you to do alot of R&D, and keeps the car easily streetable. It feels good to run above average ETs and know that it didn't cost you a fortune.
Has anyone tried installing alternating roller rockers with 2 different ratios on their LT1? Meaning like
1.6s on intake and 1.5s on exhaust or
1.5s on intake and 1.6s on exhaust or
1.7s on intake and 1.6s on exhaust or
1.6s on intake and 1.7s on exhaust
Well, you get the idea. If anyone has tried this please post gains or loses in power, ET, etc. Thanks
1.6s on intake and 1.5s on exhaust or
1.5s on intake and 1.6s on exhaust or
1.7s on intake and 1.6s on exhaust or
1.6s on intake and 1.7s on exhaust
Well, you get the idea. If anyone has tried this please post gains or loses in power, ET, etc. Thanks
I've done tons of R&D on this and the LT1 loves exhaust. I picked up over a tenth and 2 mph going from 1.6s to 1.7s. BUT, now that Comp Cams makes 1.8 rockers that fit the LT1, the playing field will be changed again.
I know plenty of guys that run GM847s on stock bottom end LT1s and that's ~.595 on the exhaust end. With 1.8s on a stock cam the lift will be .536/.551so no worries on the piston-to-valve clearance. That's awesome and only have to remove the valve covers to do it and not spend an entire weekend in the garage.
I know plenty of guys that run GM847s on stock bottom end LT1s and that's ~.595 on the exhaust end. With 1.8s on a stock cam the lift will be .536/.551so no worries on the piston-to-valve clearance. That's awesome and only have to remove the valve covers to do it and not spend an entire weekend in the garage.
how much is too much? the higher the ratio the higher the stress on the valve train right? what do you guys think an LT1 can handle w/o running into longevity problems? I realize every lil bit helps if your going the bolt-on only route but im getting cammed soon so basically what ratio should I draw the line at? dang nascar uses some giant RR's but their engines get rebuilt on a regular basis.
Got any video footage of it idling? With that staggering you will have a .515 intake lift and the exhuast remains at .520, so .515/.520 on a 112. That's tighter LSA than a hot cam, but less lift, and different duration. Good choice.
Im considering it. It has to be worth something if you change the springs and run the 1.7 or possibly even the 1.8's the only question I have is changing pushrod length. .536/.551 with the 1.8 does sound good to me no need for changing the cam and getting into the lift area I would like to be in. So and opinions?
Im considering it. It has to be worth something if you change the springs and run the 1.7 or possibly even the 1.8's the only question I have is changing pushrod length. .536/.551 with the 1.8 does sound good to me no need for changing the cam and getting into the lift area I would like to be in. So and opinions?