I'd like to squeeze a little more power out of my 97's sad little LS1 without breaking the bank and killing milage. Until recently i thought that 1.8 roller rockers weren't an option becaue of valve cover clearance.

I'm also giving thought to an LS6 intake manifold to match the rest of the intake setup.

I currently have the following:

Intake: vararam V2B2, smoth coupler, de-screened MAF sensor, ported throttle body
Exhaust: SSAC headers, Perf Curve cats, WCC x pipe, Borla stingers
Custom dyno tune by HPE.

Questions:
1) does a 1.8 roller rocker conversion yield a noticable gain (assuming re-tune)
2) what brands do you reccomend?
3) does a 1.8 RR swap require any supporting modifications?

 

Tried a search? I found half a dozen posts on this.........

 

1.8 rockers gain roughly 9hp at the wheels... you will need to swap valve springs to handle the lift (it probably couldn't hurt changing your springs anyway.)

Comp 918's look identical to stock with slightly thicker wire. They are cheap too, running about $189 new or you can find them even cheaper in the sale section. Lots of guys take them off cnc heads to swap on dual springs, so you get new stuff at a fair discount. They are good up to .600 lift...

If you add 1.8 rockers to your car you will gain roughly .30 thousands of lift to you cam specs. That will put you near .530 lift at the valve.

The downside, is that many aftermarket cams are ground with aggressive ramps and most makers state not to use 1.8 rockers (look on TSP's website for an example) So you'll have to put 1.7's back on if you swap a cam later, however you'll have already done the valvesprings.


There are many makers of rockers in both 1.7 and 1.8 ratio.... the cheapest being Harland Sharpe They are anodized orange, with a beefy design, some think you would risk valve float due to extra weight at the valve tip compared to stock, but at your rpm level and lift I wouldn't worry about that.

I had 1.8's once.... and it was a fun project... but in the end wasn't enough... then came different cams (sold the rockers) then twin turbos and more....

 

I put Yella Terra 1.8s in my Z which has similar mods to your coupe. I would recommend changing to PAC springs for the extra lift and some Comp Hi-Tech pushrods while you're there. As the above post mentioned, you will only gain a few horse power but the under the curve torque will noticably increase. And, you'll have a valve train that you can trust.

 

That's exactly what i'm looking for. What part of the torque curve sees the most improvement or is it pretty much even across the board?

 

My two dyno sheets show that the initial torque was up about 10 to 12 pounds at 2,800 rpms, then tapers to equal around 4,800, and steadly increases again to an additional 8 to 10 pounds by 6,300. (I'd scan these for you but my scanners not working) It's not all that much gain, but it is noticable (just barely) when I track the car.

 

I have Jesel 1:8's and a Comp Cam with about .575 lift. Had to grind some clearance in the valve covers , but, no biggy.

 

I would recommend the Yella Terra Ultralite's. I have seen nothing but great results from them and they are indeed "ultra light"

 

I think mine might show more improvement as i'm going from the early style LS1 manifold to the LS6 style one.

 

The manifold change alone will probably help as much or more than the 1.8s.

 

That's the plan. Plus they won't break the bank either.

 

The yella terras are great rockers, They are our biggest seller and we don't get complaints on them

 

yes...but do you get:



What $$ are they running these days?

 

About $7 American.

 

arnt those made from ground up Kudzu ?

 

HELP ME HELP ME

 

I went with the CRANE 1.8 rockers along with the CRANE cam to match. Its a great combo.