While always looking for more power , I wonder what the next stage in the evolution of my SL55 should be (?). I currently have stage V Renntech upgrades consisting of pulley upgrade, larger throttle body, carbon fiber intake, ECU, and headers. Claimed hp is 605.

What is the next move for more power? Cams? Porting? Nitrous? Anyone have upgrades from stage V and lived to tell about it? What worked best?

 

Next stage is an SLR block and cams with revised air intake. You've hit the max on air flow. Not much to be gained by porting a FI vehicle. For track runs you'll need upgraded intercooler. Saw this done on an euro E55 and it was 800 hp at the flywheel. Monster car.
Jimmy

 

How does the SLR block lead to more hp? I would assume it can just handle more power than the OEM block, and that power would come from the cams and "revised air intake"?

 

You need to focus on the cooling aspect of your setup, I would increase the overall fluid capacity of the intercooler system in conjunction with an upgraded heat exchanger.

 

They added a second intercooler and a higher flow rate intercooler pump to mine after the basic stage V kit and then modified the ECU program further (I suspect more ignition timing advance). You may also be able to run more boost.

I have tried to run a few traps with RENNtech and my local installer on more power, but so far have come up empty. I was thinking that adding methanol injection under boost would increase octane and cool the intake charge substantially, thereby allowing more boost and ignition timing advance. I have also thought about switching to turbos, air-to-air intercooler(s), and adding methanol injection.

 

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