I had the chambers rewelded to increase quench area, it was calculated that my cr was 11.6ish. When I bought the heads he didn?t tell me if they worked on the chambers so that?s why I say its calculated.
I agree with you on that, if you have a high CR detonation isn't much of a problem if you run big cams either. Only once or twice did I ever hear pinging, but I think it was cheap gas. Plus we only get 91 octane here in CA.
Vadim told me that he made a ton of HP working on the lower, not necessarily making it bigger, just better. Originally he made 220hp on the engine, and then he said that just working on the LIM he picked up 10hp. I believe him.
Before I worked on my LIM I was pulling in a consistent 28-29lbs air/min. After I made the screws flush and decreased shaft area I was pulling in 30-1Lbs air/min. I think he did the same but he wouldn't tell me
I would have used a DH UIM but I couldn't justify the price since I also would have had to upgrade to 24# injectors. I actually had the injectors, it just finding someone who could acutally work on the ECU and retune it. Most of the shops that I called around said that they could do it for about $500-600 plus the cost of renting a dyno
Originally posted by DemonSVT:
What compression ratio was/is your 3L running at?
Longer duration thrives on higher CR (and vice versa)
I'm sure that played a large part in how effective they were!
Also I bet with a real UIM your HP figures would have skyrocketed. Running large 35mm valves with those tiny SH UIM ports.
Why would a larger lower suddenly make a big difference when the upper is the piece already restricting the airflow? (I.E. If the lower is already larger then the upper. How does making the lower larger help if the upper stays the same? It's (LIM) not suddenly getting any more airflow.)
IMO the 5HP jump was mainly (3+) from the DH upper alone. The extra EH on the heads probably made up the last 1 or 2HP. The lower likely didn't account for much; if anything.
