lol yea I was looking to go to dragon race, but then i waited two weeks for them to schedule me, then 2 weeks went by and the brakes in the dyno broke, then they forgot to schedule me again. It was pretty retarded at the time...when this cam install is finished, i will mos def be contacting your buddy Chris

 

He's up in Michigan permanantly now, so he probably wont be able to do it.

 

I've got the exact cam your talking about, the 224/236 at 114 lsa in a 355. It is great and I am very happy with it. It idles right at 14 in Hg without any tuning yet. My idle has roughened up a little bit since installing the supercharger, I need to relocate the bypass valve somewhere else, the outlet to the bypass valve is too close to the MAF (it is where vortech puts it in their kit, on the intake pipe between the aftercooler and t-body). This cam is designed for superchargers with very little overlap (mine has only 2 deg of overlap). The 114 will give you a better idle than a 112, so keep that in mind also. IMO, your going to loose more boost thru a normally aspirated cam due to the increased overlap a N/A motor needs.

 

The 224/230-112 that I recommend has the same amount of overlap as the 224/236-114.

 

Okay, we'll that's good. But, what about the 6 extra degrees on the exhaust side, wouldn't that be more beneficial for a supercharger? especially with stock heads

 

How much overlap will the 224/236 on a 116lsa have?

 

Not necessarily. Keep in mind that, even though there is more mass in the cylinder you have to expell, you also have more cylinder pressure, or motive force, to help push the exhaust out.

Also, the compression ratio of a naturally aspirated engine is around 11/1, while the expansion ratio of a naturally aspirated engine remains the same, at 11/1. The compression ratio of a supercharged engine is closer to 17/1 (2/1 in the compressor then 8.5/1 in the cylinder), but the expansion ratio is only 8.5/1. With the supercharged engine, you don't expand the high pressure gasses as much as even a naturally aspirated engine would, so you lose alot of energy through the exhaust port. The advantage of a turbocharger is that you can expand it once again through the turbine and re-coup some of these losses.

Delaying exhaust valve opening by 6 degrees extends the power stroke a touch so that you don't lose so much energy out the exhaust valve.

Also, a few years back, there was an 355 LT1 car with a Procharger D1 (I think) at 18 psi with ported stock heads. He pulled 148 mph in the quarter with a 224/230-112 cam at 3600 lb. That's impressive even by today's standards.

Mike

 

wow 148 is smokin...that sounds close to the setup i will run...so no boost is lost due to the 112 lsa? I thought the 114 is better for retaining boost pressure...

 

224/230-112 has the same amount of overlap (when the boost of lost) as the ever popular 224/236-114.

Also, boost loss during overlap isn't as big of a deal as everyone thinks it is. If anything, a little fresh air blowing though the chamber will help clean out any remaining exhaust gas. When the books state that superchargers need wide LSA's, they're talking about 112 - 115, as opposed to the 102 - 106 that work best in naturally aspirated engines.

Mike

 

i just got off of the phone with a few performace shops...EPP recommended the 224/230 112 lsa like mike said....combination motorsports reccommended a 227/239 114 lsa...and dragon race engineering said that the 224/236 has too much difference in the intake and exhaust duration and that reversion is common..dragon race engineering seemed to think that neither the 224/230 112 lsa and the 224/236 114lsa would be ideal for me, and he recommended a custom ground cam...a 228/232 - 115 lsa or a 226/232 - 115 lsa. i told all of the them that i plan to forge the internals in the future and run ported stock heads/ 15-18 psi and these were the recommendations.

 

I wonder if DRE was looking at altitude when they speced that cam.

 

i would hope so....i told him that I am in Colorado Springs...are they are pretty reputable around here? I talked to Pete there and he seems to know a lot, i just dont know which cam to choose...i wish picking a cam was as easy as picking out a CAI. LOL

 

I always find these blower cam threads interesting.

To me the cam recomendations that you have aren't the best but I don't spill the beans on that much.

You can put more compression (both SCR and DCR) in your motor up there, so that's something I would look into.

Bret

 

OK, you're confusing me Mike. I hope I didn't take your quotes out of context.

 

The first quote discusses the opening side of the exhaust lobe (EVO), while the second discusses the closing side of the exhaust (EVC) during overlap. My point was that a little less duration on the exhaust will help, and putting it on a 112 won't be too much overlap.